bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Genetic and Pharmacologic Evidence That mTOR Targeting Outweighs mTORC1 Inhibition as an Antimyeloma Strategy
Authors: Chen Xi , Díaz-Rodríguez Elena , Ocio Enrique M. , Paiva Bruno , Mortensen Deborah S. , Lopez-Girona Antonia , Chopra Rajesh , Miguel Jesús San , Pandiella Atanasio
Published: April 2023

Abstract
The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that regulates cell growth, proliferation, metabolism, and cell survival, and plays those roles by forming two functionally distinct multiprotein complexes: mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). Deregulation of the mTOR pathway has been found in different cancers, including multiple myeloma. Agents acting on mTORC1, such as rapamycin and derivatives, are being explored as antitumoral strategies. However, whether targeting mTOR would be a more effective antimyeloma strategy than exclusively acting on the mTORC1 branch remains to be established. In this report, we explored the activation status of mTOR routes in malignant plasma cells, and analyzed the contribution of mTOR and its two signaling branches to the proliferation of myeloma cells. Gene expression profiling demonstrated deregulation of mTOR pathway–related genes in myeloma plasma cells from patients. Activation of the mTOR pathway in myelomatous plasma cells was corroborated by flow cytometric analyses. RNA interference (RNAi) experiments indicated that mTORC1 predominated over mTORC2 in the control of myeloma cell proliferation. However, mTOR knockdown had a superior antiproliferative effect than acting only on mTORC1 or mTORC2. Pharmacologic studies corroborated that the neutralization of mTOR has a stronger antimyeloma effect than the individual inhibition of mTORC1 or mTORC2. Together, our data support the clinical development of agents that widely target mTOR, instead of agents, such as rapamycin or its derivatives, that solely act on mTORC1. Mol Cancer Ther; 13(2); 504–16. ©2014 AACR.
Data from MM-141, an IGF-IR– and ErbB3-Directed Bispecific Antibody, Overcomes Network Adaptations That Limit Activity of IGF-IR Inhibitors
Authors: Fitzgerald Jonathan B. , Johnson Bryan W. , Baum Jason , Adams Sharlene , Iadevaia Sergio , Tang Jian , Rimkunas Victoria , Xu Lihui , Kohli Neeraj , Rennard Rachel , Razlog Maja , Jiao Yang , Harms Brian D. , Olivier Kenneth J. , Schoeberl Birgit , Nielsen Ulrik B. , Lugovskoy Alexey A.
Published: April 2023

Abstract
Although inhibition of the insulin-like growth factor (IGF) signaling pathway was expected to eliminate a key resistance mechanism for EGF receptor (EGFR)-driven cancers, the effectiveness of IGF-I receptor (IGF-IR) inhibitors in clinical trials has been limited. A multiplicity of survival mechanisms are available to cancer cells. Both IGF-IR and the ErbB3 receptor activate the PI3K/AKT/mTOR axis, but ErbB3 has only recently been pursued as a therapeutic target. We show that coactivation of the ErbB3 pathway is prevalent in a majority of cell lines responsive to IGF ligands and antagonizes IGF-IR–mediated growth inhibition. Blockade of the redundant IGF-IR and ErbB3 survival pathways and downstream resistance mechanisms was achieved with MM-141, a tetravalent bispecific antibody antagonist of IGF-IR and ErbB3. MM-141 potency was superior to monospecific and combination antibody therapies and was insensitive to variation in the ratio of IGF-IR and ErbB3 receptors. MM-141 enhanced the biologic impact of receptor inhibition in vivo as a monotherapy and in combination with the mTOR inhibitor everolimus, gemcitabine, or docetaxel, through blockade of IGF-IR and ErbB3 signaling and prevention of PI3K/AKT/mTOR network adaptation. Mol Cancer Ther; 13(2); 410–25. ©2013 AACR.
Data from Identification of Transmembrane Protein 98 as a Novel Chemoresistance-Conferring Gene in Hepatocellular Carcinoma
Authors: Ng Kevin Tak-Pan , Lo Chung Mau , Guo Dong Yong , Qi Xiang , Li Chang Xian , Geng Wei , Liu Xiao Bing , Ling Chang Chun , Ma Yuen Yuen , Yeung Wai Ho , Shao Yan , Poon Ronnie Tung-Ping , Fan Sheung Tat , Man Kwan
Published: April 2023

Abstract
Chemoresistance is one of the major obstacles in systemic chemotherapy and targeted therapy for patients with advanced hepatocellular carcinoma. To identify novel chemoresistance-associated targets in hepatocellular carcinoma, chemoresistant hepatocellular carcinoma cell lines were established. By comparing the global gene expression profiles between chemoresistant and chemosensitive cell lines, eight novel chemoresistance-associated genes were identified to be significantly associated with the commonly augmented chemoresistance of hepatocellular carcinoma cells. One upregulated candidate named transmembrane protein 98 (TMEM98) was found to be overexpressed in 80 of 118 (67.80%) of patients with hepatocellular carcinoma. TMEM98 mRNA in tumor tissues was significantly higher than nontumor tissues of patients with hepatocellular carcinoma (P < 0.0001). Upregulation of TMEM98 was significantly correlated with advanced tumor stage (P = 0.048), high incidence of early tumor recurrence (P = 0.005), poor overall survival (P = 0.029), and poor disease-free survival (P = 0.011) of patients with hepatocellular carcinoma after hepatectomy. Importantly, upregulation of TMEM98 mRNA in patients with hepatocellular carcinoma who received transarterial chemoembolization (TACE) treatment was significantly higher than in patients without TACE treatment (P = 0.046). Moreover, patients with poor response to TACE treatment had higher degree of TMEM98 upregulation than the responsive patients. In vitro and in vivo studies showed that suppression of TMEM98 in chemoresistant hepatocellular carcinoma cells restored their chemosensitivity, while forced overexpression of TMEM98 enhanced their chemoresistance. The mechanism of TMEM98 in conferring chemoresistance of hepatocellular carcinoma might be possibly through activation of the AKT pathway and deactivation of p53. In conclusion, we identified a panel of novel common chemoresistance-associated genes and demonstrated that TMEM98 is a chemoresistance-conferring gene in hepatocellular carcinoma. Mol Cancer Ther; 13(5); 1285–97. ©2014 AACR.
Data from PUMA Induction by FoxO3a Mediates the Anticancer Activities of the Broad-Range Kinase Inhibitor UCN-01
Authors: Dudgeon Crissy , Wang Peng , Sun Xiameng , Peng Rui , Sun Quanhong , Yu Jian , Zhang Lin
Published: April 2023

Abstract
Most targeted anticancer drugs are inhibitors of kinases that are aberrantly activated in cancer cells. However, the mechanisms by which kinase inhibitors suppress tumor growth remain unclear. In this study, we found that UCN-01, a staurosporine analogue and broad-range kinase inhibitor used in clinical trials, inhibits colon cancer cell growth by inducing apoptosis via PUMA, a BH3-only Bcl-2 family member and a p53 target. PUMA expression was markedly elevated in a p53-independent fashion following UCN-01 treatment. The induction of PUMA by UCN-01 was mediated by direct binding of FoxO3a to the PUMA promoter following inhibition of AKT signaling. Deficiency in PUMA abrogated UCN-01–induced apoptosis, caspase activation, and mitochondrial dysfunction, and rendered UCN-01 resistance in a clonogenic assay, whereas elevated PUMA expression or a BH3 mimetic sensitized UCN-01 induced apoptosis. Chemosensitization by UCN-01 seemed to involve simultaneous PUMA induction through both p53-dependent and p53-independent mechanisms. Furthermore, deficiency in PUMA suppressed the antitumor effects of UCN-01 in a xenograft model, concurrent with reduced apoptosis and caspase activation in vivo. These results suggest that PUMA-mediated apoptosis is pivotal for the anticancer activities of UCN-01, and possibly other clinically used kinase inhibitor drugs, and that PUMA manipulation may be useful for improving their anticancer activities. Mol Cancer Ther; 9(11); 2893–902. ©2010 AACR.
Data from Doxycycline as an Inhibitor of the Epithelial-to-Mesenchymal Transition and Vasculogenic Mimicry in Hepatocellular Carcinoma
Authors: Meng Jie , Sun Baocun , Zhao Xiulan , Zhang Danfang , Zhao Xueming , Gu Qiang , Dong Xueyi , Zhao Nan , Liu Peimei , Liu Yanrong
Published: April 2023

Abstract
This study was conducted to examine the effects of doxycycline on the survival time and proliferation of hepatocellular carcinoma (HCC) in vivo and on the biologic functions of HCC in vitro. This study was also designed to evaluate the effects of doxycycline on epithelial-to-mesenchymal transition (EMT)– and vasculogenic mimicry (VM)–related protein expression and on matrix metalloproteinase (MMP) and DNA methyltransferase (DNMT) activity in vitro. Human MHCC97H cells were injected into BALB/c mice, which were divided into treatment and control groups. Doxycycline treatment prolonged the mouse survival time and partly suppressed the growth of engrafted HCC tumor cells, with an inhibition rate of 43.39%. Higher amounts of VM and endothelium-dependent vessels were found in the control group than the treatment group. IHC indicated that epithelial (E)-cadherin expression was increased in the doxycycline-treated mice compared with the control group. In in vitro experiments, doxycycline promoted HCC cell adhesion but inhibited HCC cell viability, proliferation, migration, and invasion. Western blot analysis, semiquantitative RT-PCR, qRT-PCR, and immunofluorescence demonstrated that doxycycline inhibited the degradation of the epithelial marker E-cadherin and downregulated the expression levels of EMT promoters, the mesenchymal marker vimentin, and the VM-associated marker vascular endothelial (VE)-cadherin. Furthermore, the activities of MMPs and DNMTs were examined in different groups via gelatin zymography and a DNMT activity assay kit. A methylation-specific PCR was performed to assess the promoter methylation of CDH1 (the gene encoding E-cadherin). Doxycycline prolonged the mouse survival time by inhibiting EMT progression and VM formation. Mol Cancer Ther; 13(12); 3107–22. ©2014 AACR.
Data from Overlapping Functions of ABC Transporters in Topotecan Disposition as Determined in Gene Knockout Mouse Models
Authors: Tiwari Amit K. , Zhang Rong , Gallo James M.
Published: April 2023

Abstract
It is established that efflux transporters of the ATP-binding cassette (ABC) superfamily can affect the pharmacokinetics of drugs through mechanisms pertaining to drug absorption, elimination, and distribution. To characterize the role of multiple transporters in topotecan's pharmacokinetics, total (lactone+carboxylate) and lactone forms were measured by liquid chromatography/tandem mass spectrometry (LC/MS-MS) in plasma, bile, urine, and feces following intravenous administration at doses of 1 and 4 mg/kg to eight mouse strains: C57BL/6 [wild-type (WT)], Abcb1−/−, Abcc2−/−, Abcc4−/−, Abcg2−/−, Abcc2;Abcb1−/−, Abcc2;Abcg2−/−, and Abcc4;Abcg2−/−. Compared with WT mice and at both dose levels, the plasma areas under the curve for topotecan lactone were not significantly different in the Abcc2−/−, Abcc4−/−, and Abcb1−/− strains, whereas significant differences were found in Abcg2−/−, Abcc2;Abcb1−/− (only at the high dose), Abcc4;Abcg2−/−, and Abcc2;Abcg2−/− mice and ranged from 2.1- to 3.3-fold higher. Consistent with these changes, the fecal and biliary excretion of topotecan was reduced, whereas renal elimination was elevated in Abcg2−/−-based strains. Similarly, the Abcc2;Abcb1−/− strain also had elevated renal elimination and reduced fecal excretion of topotecan lactone. This was more pronounced at the 4 mg/kg dose level, suggesting possible saturation of Abcg2. The Abcc4 transporter was found not to be a major determinant of topotecan pharmacokinetics. It is concluded that Abcg2 has the most significant effect on topotecan elimination, whereas both Abcb1 and Abcc2 have overlapping functions with Abcg2. As such it is relevant to examine how polymorphisms in these transporters influence topotecan activity in patients and whether coadministration of transport modulators could positively affect efficacy without increasing toxicity. Mol Cancer Ther; 12(7); 1343–55. ©2013 AACR.
Data from ATF4 Gene Network Mediates Cellular Response to the Anticancer PAD Inhibitor YW3-56 in Triple-Negative Breast Cancer Cells
Authors: Wang Shu , Chen Xiangyun Amy , Hu Jing , Jiang Jian-kang , Li Yunfei , Chan-Salis Ka Yim , Gu Ying , Chen Gong , Thomas Craig , Pugh B. Franklin , Wang Yanming
Published: April 2023

Abstract
We previously reported that a pan-PAD inhibitor, YW3-56, activates p53 target genes to inhibit cancer growth. However, the p53-independent anticancer activity and molecular mechanisms of YW3-56 remain largely elusive. Here, gene expression analyses found that ATF4 target genes involved in endoplasmic reticulum (ER) stress response were activated by YW3-56. Depletion of ATF4 greatly attenuated YW3-56–mediated activation of the mTORC1 regulatory genes SESN2 and DDIT4. Using the ChIP-exo method, high-resolution genomic binding sites of ATF4 and CEBPB responsive to YW3-56 treatment were generated. In human breast cancer cells, YW3-56–mediated cell death features mitochondria depletion and autophagy perturbation. Moreover, YW3-56 treatment effectively inhibits the growth of triple-negative breast cancer xenograft tumors in nude mice. Taken together, we unveiled the anticancer mechanisms and therapeutic potentials of the pan-PAD inhibitor YW3-56. Mol Cancer Ther; 14(4); 877–88. ©2015 AACR.
Data from Cambogin Induces Caspase-Independent Apoptosis through the ROS/JNK Pathway and Epigenetic Regulation in Breast Cancer Cells
Authors: Shen Kaikai , Xie Jianling , Wang Hua , Zhang Hong , Yu Mengyuan , Lu Fangfang , Tan Hongsheng , Xu Hongxi
Published: April 2023

Abstract
Cambogin is a polycyclic polyprenylated acylphoroglucinol (PPAP) from the Garcinia genus, which has been used traditionally for cancer treatment across Southeastern Asia. In this study, we found that cambogin inhibited breast cancer cell proliferation and induced cell apoptosis in vitro. Cambogin induced the activation of the caspase-independent mitochondrial apoptotic pathway, as indicated by an increase in the ratio of Bax/Bcl-2 and the nuclear translocation of apoptosis inducing factor (AIF). Two-dimensional gel electrophoresis and mass spectrometry revealed that the expression of proteins involving in the radical oxygen species (ROS) pathway was among the most affected upon cambogin treatment. Cambogin enhanced cellular ROS production, and induced the activation of the ASK1–MKK4/MKK7–JNK/SAPK signaling pathway. Pretreatment with ROS scavenger N-acetylcysteine (NAC), an antioxidant, or the JNK inhibitor SP600125 was able to restore cell viability in the presence of cambogin. Importantly, cambogin treatment led to the activation of activating transcription factor-2 (ATF-2) and the trimethylation of histone H3K9 in the activator protein 1 (AP-1) binding region of the Bcl-2 gene promoter. Finally, cambogin exhibited a potential antitumor effect in MCF-7 breast cancer xenografts without apparent toxicity. Taken in conjunction, the present study indicates that cambogin can induce breast adenocarcinoma cell apoptosis and therefore represents therapeutic potential for cancer treatment. Mol Cancer Ther; 14(7); 1738–49. ©2015 AACR.
Data from Berberine Induces Senescence of Human Glioblastoma Cells by Downregulating the EGFR–MEK–ERK Signaling Pathway
Authors: Liu Qiao , Xu Xiuhua , Zhao Minnan , Wei Zhao , Li Xi , Zhang Xiyu , Liu Zhaojian , Gong Yaoqin , Shao Changshun
Published: April 2023

Abstract
Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor and has a poor prognosis. We, here, report a potent antitumor effect of berberine, an isoquinoline alkaloid, on GBM. Berberine was found to have an IC50 that is much lower than temozolomide in vitro in U87, U251, and U118 glioblastoma cells. Although previous studies showed that berberine primarily exerts its anticancer effect by inducing cell-cycle arrest, apoptosis, and autophagy, we observed that the antitumor effect of berberine on glioblastoma cells was primarily achieved through induction of cellular senescence. In glioblastoma cells treated with berberine, the level of epidermal growth factor receptor (EGFR) was greatly reduced. Examination of the activities of the kinases downstream of EGFR revealed that the RAF–MEK–ERK signaling pathway was remarkably inhibited, whereas AKT phosphorylation was not altered. Pharmacologic inhibition or RNA interference of EGFR similarly induced cellular senescence of glioblastoma cells. Furthermore, the cellular senescence induced by berberine could be rescued by introduction of a constitutive active MKK. Berberine also potently inhibited the growth of tumor xenografts, which was accompanied by downregulation of EGFR and induction of senescence. Our findings thus revealed a new route by which berberine exerts its anticancer activity. Because EGFR is commonly upregulated in glioblastoma, the demonstration of effective inhibition of EGFR by berberine points to the possibility of using berberine in the treatment of patients with glioblastoma. Mol Cancer Ther; 14(2); 355–63. ©2014 AACR.
Data from Preclinical Pharmacokinetics, Tolerability, and Pharmacodynamics of Metuzumab, a Novel CD147 Human–Mouse Chimeric and Glycoengineered Antibody
Authors: Zhang Zheng , Zhang Yang , Sun Qian , Feng Fei , Huhe Muren , Mi Li , Chen Zhinan
Published: April 2023

Abstract
Metuzumab is an affinity-optimized and nonfucosylated anti-CD147 human–mouse chimeric IgG1 monoclonal antibody with enhanced antibody-dependent cellular cytotoxicity (ADCC). The purpose of this study was to characterize the pharmacokinetics, safety, and antitumor activities of metuzumab in mouse, rat, and monkey. The ADCC activity was assessed by a lactate dehydrogenase release assay. The pharmacokinetics of metuzumab were determined in Sprague–Dawley rats and in cynomolgus monkeys. Single- and repeat-dose toxicology studies of the i.v. administration of high-dose metuzumab were conducted in cynomolgus monkeys. Mice bearing human tumor xenografts were used to evaluate the antitumor efficacy of metuzumab. The ADCC potency of metuzumab was enhanced compared with the nonglycoengineered parental antibody. Metuzumab also effectively inhibited tumor growth in A549 and NCI-H520 xenograft models. In the monkey model, the total clearance of metuzumab decreased with increasing dose. The nonspecific clearance in monkeys was estimated to be 0.53 to 0.92 mL/h/kg. In single- and repeat-dose toxicology studies in cynomolgus monkeys, metuzumab did not induce any distinct or novel adverse findings and was well tolerated at all tested doses. These preclinical safety data facilitated the initiation of an ongoing clinical trial of metuzumab for the treatment of non–small cell lung cancer (NSCLC) in China. Mol Cancer Ther; 14(1); 162–73. ©2014 AACR.
Data from Selective Inhibition of SIN3 Corepressor with Avermectins as a Novel Therapeutic Strategy in Triple-Negative Breast Cancer
Authors: Kwon Yeon-Jin , Petrie Kevin , Leibovitch Boris A. , Zeng Lei , Mezei Mihaly , Howell Louise , Gil Veronica , Christova Rossitza , Bansal Nidhi , Yang Shuai , Sharma Rajal , Ariztia Edgardo V. , Frankum Jessica , Brough Rachel , Sbirkov Yordan , Ashworth Alan , Lord Christopher J. , Zelent Arthur , Farias Eduardo , Zhou Ming-Ming , Waxman Samuel
Published: April 2023

Abstract
Triple-negative breast cancers (TNBC) lacking estrogen, progesterone, and HER2 receptors account for 10% to 20% of breast cancer and are indicative of poor prognosis. The development of effective treatment strategies therefore represents a pressing unmet clinical need. We previously identified a molecularly targeted approach to target aberrant epigenetics of TNBC using a peptide corresponding to the SIN3 interaction domain (SID) of MAD. SID peptide selectively blocked binding of SID-containing proteins to the paired α-helix (PAH2) domain of SIN3, resulting in epigenetic and transcriptional modulation of genes associated with epithelial–mesenchymal transition (EMT). To find small molecule inhibitor (SMI) mimetics of SID peptide, we performed an in silico screen for PAH2 domain–binding compounds. This led to the identification of the avermectin macrocyclic lactone derivatives selamectin and ivermectin (Mectizan) as candidate compounds. Both selamectin and ivermectin phenocopied the effects of SID peptide to block SIN3–PAH2 interaction with MAD, induce expression of CDH1 and ESR1, and restore tamoxifen sensitivity in MDA-MB-231 human and MMTV-Myc mouse TNBC cells in vitro. Treatment with selamectin or ivermectin led to transcriptional modulation of genes associated with EMT and maintenance of a cancer stem cell phenotype in TNBC cells. This resulted in impairment of clonogenic self-renewal in vitro and inhibition of tumor growth and metastasis in vivo. Underlining the potential of avermectins in TNBC, pathway analysis revealed that selamectin also modulated the expression of therapeutically targetable genes. Consistent with this, an unbiased drug screen in TNBC cells identified selamectin-induced sensitization to a number of drugs, including those targeting modulated genes. Mol Cancer Ther; 14(8); 1824–36. ©2015 AACR.
Data from Inhibition of Isoprenylcysteine Carboxylmethyltransferase Induces Cell-Cycle Arrest and Apoptosis through p21 and p21-Regulated BNIP3 Induction in Pancreatic Cancer
Authors: Manu Kanjoormana Aryan , Chai Tin Fan , Teh Jing Tsong , Zhu Wan Long , Casey Patrick J. , Wang Mei
Published: April 2023

Abstract
Pancreatic cancer remains one of the most difficult to treat human cancers despite recent advances in targeted therapy. Inhibition of isoprenylcysteine carboxylmethyltransferase (ICMT), an enzyme that posttranslationally modifies a group of proteins including several small GTPases, suppresses proliferation of some human cancer cells. However, the efficacy of ICMT inhibition on human pancreatic cancer has not been evaluated. In this study, we have evaluated a panel of human pancreatic cancer cell lines and identified those that are sensitive to ICMT inhibition. In these cells, ICMT suppression inhibited proliferation and induced apoptosis. This responsiveness to ICMT inhibition was confirmed in in vivo xenograft tumor mouse models using both a small-molecule inhibitor and shRNA-targeting ICMT. Mechanistically, we found that, in sensitive pancreatic cancer cells, ICMT inhibition induced mitochondrial respiratory deficiency and cellular energy depletion, leading to significant upregulation of p21. Furthermore, we characterized the role of p21 as a regulator and coordinator of cell signaling that responds to cell energy depletion. Apoptosis, but not autophagy, that is induced via p21-activated BNIP3 expression accounts for the efficacy of ICMT inhibition in sensitive pancreatic cancer cells in both in vitro and in vivo models. In contrast, cells resistant to ICMT inhibition demonstrated no mitochondria dysfunction or p21 signaling changes under ICMT suppression. These findings not only identify pancreatic cancers as potential therapeutic targets for ICMT suppression but also provide an avenue for identifying those subtypes that would be most responsive to agents targeting this critical enzyme. Mol Cancer Ther; 16(5); 914–23. ©2017 AACR.
Data from AC0010, an Irreversible EGFR Inhibitor Selectively Targeting Mutated EGFR and Overcoming T790M-Induced Resistance in Animal Models and Lung Cancer Patients
Authors: Xu Xiao , Mao Long , Xu Wanhong , Tang Wei , Zhang Xiaoying , Xi Biao , Xu Rongda , Fang Xin , Liu Jia , Fang Ce , Zhao Li , Wang Xiaobo , Jiang Ji , Hu Pei , Zhao Hongyun , Zhang Li
Published: April 2023

Abstract
AC0010 is a pyrrolopyrimidine-based irreversible EGFR inhibitor, structurally distinct from previously reported pyrimidine-based irreversible EGFR inhibitors, such as osimertinib and rociletinib. AC0010 selectively inhibits EGFR-active and T790M mutations with up to 298-fold increase in potency compared with wild-type EGFR. In a xenograft model, oral administration of AC0010 at a daily dose of 500 mg/kg resulted in complete remission of tumors with EGFR-active and T790M mutations for over 143 days with no weight loss. Three major metabolites of AC0010 were tested and showed no wild-type EGFR inhibition or off-target effects, such as inhibition of IGF-1R. AC0010 is safe in non–small cell lung cancer (NSCLC) patients at a dose range between 50 and 550 mg once per day, and no hyperglycemia or other severe adverse effects were detected, such as grade 3 QT prolongation. The objective responses were observed in NSCLC patients with EGFR T790M mutation. Mol Cancer Ther; 15(11); 2586–97. ©2016 AACR.
Data from Acquired Resistance to BET-PROTACs (Proteolysis-Targeting Chimeras) Caused by Genomic Alterations in Core Components of E3 Ligase Complexes
Authors: Zhang Lu , Riley-Gillis Bridget , Vijay Priyanka , Shen Yu
Published: April 2023

Abstract
Proteolysis-targeting chimeras (PROTAC) are bifunctional molecules that hijack endogenous E3 ubiquitin ligases to induce ubiquitination and subsequent degradation of protein of interest. Recently, it has been shown that PROTACs with robust in vitro and in vivo activities and, in some cases, drug-like pharmaceutical properties can be generated using small-molecule ligands for the E3 ligases VHL and CRBN. These findings stoked tremendous enthusiasm on using PROTACs for therapeutics development. Innate and acquired drug resistance often underlies therapeutic failures, particularly for cancer therapy. With the PROTAC technology progressing rapidly toward therapeutic applications, it would be important to understand whether and how resistance to these novel agents may emerge. Using BET-PROTACs as a model system, we demonstrate that resistance to both VHL- and CRBN-based PROTACs can occur in cancer cells following chronic treatment. However, unlike what was often observed for many targeted therapeutics, resistance to BET-PROTACs did not result from secondary mutations that affect compound binding to the target. In contrast, acquired resistance to both VHL- and CRBN-based BET-PROTACs was primarily caused by genomic alterations that compromise core components of the relevant E3 ligase complexes.
Data from SHP2 Inhibition Overcomes RTK-Mediated Pathway Reactivation in KRAS-Mutant Tumors Treated with MEK Inhibitors
Authors: Lu Hengyu , Liu Chen , Velazquez Roberto , Wang Hongyun , Dunkl Lukas Manuel , Kazic-Legueux Malika , Haberkorn Anne , Billy Eric , Manchado Eusebio , Brachmann Saskia M. , Moody Susan E. , Engelman Jeffrey A. , Hammerman Peter S. , Caponigro Giordano , Mohseni Morvarid , Hao Huai-Xiang
Published: April 2023

Abstract
FGFR1 was recently shown to be activated as part of a compensatory response to prolonged treatment with the MEK inhibitor trametinib in several KRAS-mutant lung and pancreatic cancer cell lines. We hypothesize that other receptor tyrosine kinases (RTK) are also feedback-activated in this context. Herein, we profile a large panel of KRAS-mutant cancer cell lines for the contribution of RTKs to the feedback activation of phospho-MEK following MEK inhibition, using an SHP2 inhibitor (SHP099) that blocks RAS activation mediated by multiple RTKs. We find that RTK-driven feedback activation widely exists in KRAS-mutant cancer cells, to a less extent in those harboring the G13D variant, and involves several RTKs, including EGFR, FGFR, and MET. We further demonstrate that this pathway feedback activation is mediated through mutant KRAS, at least for the G12C, G12D, and G12V variants, and wild-type KRAS can also contribute significantly to the feedback activation. Finally, SHP099 and MEK inhibitors exhibit combination benefits inhibiting KRAS-mutant cancer cell proliferation in vitro and in vivo. These findings provide a rationale for exploration of combining SHP2 and MAPK pathway inhibitors for treating KRAS-mutant cancers in the clinic.
Data from Morin Inhibits Proliferation and Induces Apoptosis by Modulating the miR-188-5p/PTEN/AKT Regulatory Pathway in CML Cells
Authors: Nie Zi-Yuan , Yang Lin , Liu Xiao-Jun , Yang Zhan , Yang Gao-Shan , Zhou Jing , Qin Yan , Yu Jing , Jiang Ling-Ling , Wen Jin-Kun , Luo Jian-Min
Published: April 2023

Abstract
Increased activity of the PI3K/AKT/mTOR pathway has been observed in chronic myeloid leukemia (CML). Morin, a kind of flavonoid, exhibits a significant anticancer activity by suppressing the PI3K/AKT signaling pathway. However, the effect of morin on CML and its underlying mechanisms is poorly understood. Here, we found that morin dose dependently inhibited the proliferation of CML cell lines K562 and KCL22 and induced their apoptosis, with a significant increase in cell apoptosis upon exposure of cells to 50 μmol/L morin. Moreover, morin significantly reduced CML xenograft growth in nude mice. Mechanically, morin attenuated phosphorylated AKT level by upregulating PTEN expression, thus leading to the inhibition of AKT signaling. Knockdown of PTEN by its siRNA completely abrogated morin-induced cell apoptosis, indicating that PTEN mediates the inductive effect of morin on CML cell apoptosis. More importantly, we found that miR-188-5p was significantly upregulated in CML patients and CML cell lines. Treating CML cells with morin markedly downregulated the miR-188-5p expression level. Further, we demonstrated that miR-188-5p repressed PTEN expression by directly targeting its 3′-UTR. miR-188-5p downregulation induced by morin enhanced CML cell apoptosis by relieving miR-188-5p repression of PTEN expression. In summary, morin exerts significant anticancer efficacy in CML by regulating the miR-188-5p/PTEN axis and thus repressing the PI3K/AKT signaling.
Data from Targeting AKT with Oridonin Inhibits Growth of Esophageal Squamous Cell Carcinoma In Vitro and Patient-Derived Xenografts In Vivo
Authors: Song Mengqiu , Liu Xuejiao , Liu Kangdong , Zhao Ran , Huang Hai , Shi Yuanyuan , Zhang Man , Zhou Silei , Xie Hua , Chen Hanyong , Li Yin , Zheng Yan , Wu Qiong , Liu Fangfang , Li Enmin , Bode Ann M. , Dong Zigang , Lee Mee-Hyun
Published: April 2023

Abstract
Overexpression or activation of AKT is very well known to control cell growth, survival, and gene expression in solid tumors. Oridonin, an inflammatory medical and diterpenoid compound isolated from Rabdosia rubescens, has exhibited various pharmacologic and physiologic properties, including antitumor, antibacterial, and anti-inflammatory effects. In this study, we demonstrated that oridonin is an inhibitor of AKT and suppresses proliferation of esophageal squamous cell carcinoma (ESCC) in vitro and in vivo. The role of AKT in ESCC was studied using immuno-histochemical analysis of a tumor microarray, the effect of AKT knockdown on cell growth, and treatment of cells with MK-2206, an AKT inhibitor. Oridonin blocked AKT kinase activity and interacted with the ATP-binding pocket of AKT. It inhibited growth of KYSE70, KYSE410, and KYSE450 esophageal cancer cells in a time- and concentration-dependent manner. Oridonin induced arrest of cells in the G2–M cell-cycle phase, stimulated apoptosis, and increased expression of apoptotic biomarkers, including cleaved PARP, caspase-3, caspase-7, and Bims in ESCC cell lines. Mechanistically, we found that oridonin diminished the phosphorylation and activation of AKT signaling. Furthermore, a combination of oridonin and 5-fluorouracil or cisplatin (clinical chemotherapeutic agents) enhanced the inhibition of ESCC cell growth. The effects of oridonin were verified in patient-derived xenograft tumors expressing high levels of AKT. In summary, our results indicate that oridonin acts as an AKT inhibitor to suppress the growth of ESCC by attenuating AKT signaling. Mol Cancer Ther; 17(7); 1540–53. ©2018 AACR.
Data from Reduction of Muscle-Invasive Tumors by Photodynamic Therapy with Tetrahydroporphyrin-Tetratosylat in an Orthotopic Rat Bladder Cancer Model
Authors: Berndt-Paetz Mandy , Schulze Philipp , Stenglein Philipp C. , Weimann Annett , Wang Qiang , Horn Lars-Christian , Riyad Yasser M. , Griebel Jan , Hermann Ralf , Glasow Annegret , Stolzenburg Jens-Uwe , Neuhaus Jochen
Published: April 2023

Abstract
Photodynamic therapy (PDT) is a promising option for minimal-invasive treatment of bladder cancer. Efficacy of PDT in muscle-invasive urothelial cancer is still hampered by low tissue penetration of most photosensitizers due to short excitation wavelength. The novel light reactive agent tetrahydroporphyrin-tetratosylat (THPTS) is excitable at near-infrared (760 nm), allowing tissue penetration of up to 15 mm. Here, we established an orthotopic rat bladder cancer model and examined the effects of THPTS-PDT on tumor growth in vivo, and analyzed molecular mechanisms in vitro. We examined pharmacokinetics and subcellular localization, and evoked cell death mode in cultured rat urothelial carcinoma cells (AY-27). We used female F344 Fischer rats for in vivo studies. Ten rats each were used for THPTS-PDT and light-only control. Bladders were evaluated by macroscopy and histology. Temperature-dependent THPTS uptake resulted in endosomal/lysosomal localization. PDT (0–50 μmol/L THPTS; 10 J/cm2) induced early onset of apoptosis leading to dose-dependent cytotoxicity in AY-27 cells. Single-time transurethral THPTS-PDT (100 μmol/L THPTS; 10 J/cm2) in F344 rats led to significant reduction of muscle-invasive tumor number (2/10 vs. 7/10 in controls) and total tumor volume (60% reduction) 2 weeks after PDT, while sparing healthy tissue. Here, we report for the first time effective tumor growth control by PDT in vivo. THPTS is a promising new photosensitizer with the advantage of higher therapeutic depth and the potential of high-selective therapy in muscle-invasive urothelial cancer. This approach possibly allows minimal-invasive bladder preserving treatment of bladder cancer without systemic side effects.
Data from MiRNA-203 Reduces Nasopharyngeal Carcinoma Radioresistance by Targeting IL8/AKT Signaling
Authors: Qu Jia-Quan , Yi Hong-Mei , Ye Xu , Zhu Jin-Feng , Yi Hong , Li Li-Na , Xiao Ta , Yuan Li , Li Jiao-Yang , Wang Yuan-Yuan , Feng Juan , He Qiu-Yan , Lu Shan-Shan , Xiao Zhi-Qiang
Published: April 2023

Abstract
Radioresistance poses a major challenge in nasopharyngeal carcinoma (NPC) treatment, but little is known about how miRNA (miR) regulates this phenomenon. In this study, we investigated the function and mechanism of miR-203 in NPC radioresistance, one of downregulated miRs in the radioresistant NPC cells identified by our previous microarray analysis. We observed that miR-203 was frequently downregulated in the radioresistant NPC tissues compared with radiosensitive NPC tissues, and its decrement significantly correlated with NPC radioresistance and poor patient survival, and was an independent predictor for reduced patient survival. In vitro radioresponse assays showed that miR-203 mimic markedly decreased NPC cell radioresistance. In a mouse model, therapeutic administration of miR-203 agomir dramatically sensitized NPC xenografts to irradiation. Mechanistically, we confirmed that IL8 was a direct target of miR-203, and found that reduced miR-203 promoted NPC cell radioresistance by activating IL8/AKT signaling. Moreover, the levels of IL8 and phospho-AKT were significantly increased in the radioresistant NPC tissues compared with radiosensitive NPC tissues, and negatively associated with miR-203 level. Our data demonstrate that miR-203 is a critical determinant of NPC radioresponse, and its decrement enhances NPC radioresistance through targeting IL8/AKT signaling, highlighting the therapeutic potential of the miR-203/IL8/AKT signaling axis in NPC radiosensitization. Mol Cancer Ther; 14(11); 2653–64. ©2015 AACR.
Data from Acquired Resistance to EGFR TKIs Mediated by TGFβ1/Integrin β3 Signaling in EGFR-Mutant Lung Cancer
Authors: Wang Caiyun , Wang Tao , Lv Dacheng , Li Ling , Yue Jinnan , Chen Hong-Zhuan , Xu Lu
Published: April 2023

Abstract
Investigation of novel molecular mechanisms is essential to develop strategies to overcome acquired resistance to EGFR tyrosine kinase inhibitors (TKI). Integrin has been demonstrated as a regulator of cancer progression. The aim of this study was to identify which specific integrins are involved and regulated in acquired resistance to EGFR TKIs in EGFR-mutant lung cancer. The expression levels of integrin subunits were examined in EGFR-mutant lung cancer cells and xenograft tumors with acquired resistance to EGFR TKIs. Manipulation of integrin β3 was performed to explore whether integrin β3 overexpression was associated with TKI resistance, anoikis resistance, EMT, and cancer stemness in resistant lung cancer. To explore the mechanism, TGFβ1 level was examined, and TGFβ1 inhibitor was then used. Integrin β3 was dramatically and consistently overexpressed in acquired gefitinib- or osimertinib-resistant lung cancer in vitro and in vivo. Integrin β3 was also involved in the progression of lung adenocarcinoma. Antagonizing integrin β3 increased the TKI sensitivity and delayed the occurrence of TKI resistance in vitro and in vivo, as well as suppressed proliferation, anoikis resistance, and EMT phenotype in lung cancer cells. Overexpression of integrin β3 was also associated with the enhanced cancer stemness that was acquired in the development of resistance and suppressed by antagonizing integrin β3. Mechanistically, integrin β3 was induced by increased TGFβ1 levels in acquired TKI-resistant lung cancer. Our study identified the TGFβ1/integrin β3 axis as a promising target for combination therapy to delay or overcome acquired resistance to EGFR TKIs in EGFR-mutant lung cancer.
Data from Mechanisms of Acquired Resistance to Trastuzumab Emtansine in Breast Cancer Cells
Authors: Li Guangmin , Guo Jun , Shen Ben-Quan , Yadav Daniela Bumbaca , Sliwkowski Mark X. , Crocker Lisa M. , Lacap Jennifer A. , Phillips Gail D. Lewis
Published: April 2023

Abstract
The receptor tyrosine kinase HER2 is overexpressed in approximately 20% of breast cancer, and its amplification is associated with reduced survival. Trastuzumab emtansine (Kadcyla, T-DM1), an antibody–drug conjugate that is comprised of trastuzumab covalently linked to the antimitotic agent DM1 through a stable linker, was designed to selectively deliver DM1 to HER2-overexpressing tumor cells. T-DM1 is approved for the treatment of patients with HER2-positive metastatic breast cancer following progression on trastuzumab and a taxane. Despite the improvement in clinical outcome, many patients who initially respond to T-DM1 treatment eventually develop progressive disease. The mechanisms that contribute to T-DM1 resistance are not fully understood. To this end, we developed T-DM1–resistant in vitro models to examine the mechanisms of acquired T-DM1 resistance. We demonstrate that decreased HER2 and upregulation of MDR1 contribute to T-DM1 resistance in KPL-4 T-DM1–resistant cells. In contrast, both loss of SLC46A3 and PTEN deficiency play a role in conferring resistance in BT-474M1 T-DM1–resistant cells. Our data suggest that these two cell lines acquire resistance through distinct mechanisms. Furthermore, we show that the KPL-4 T-DM1 resistance can be overcome by treatment with an inhibitor of MDR1, whereas a PI3K inhibitor can rescue PTEN loss–induced resistance in T-DM1–resistant BT-474M1 cells. Our results provide a rationale for developing therapeutic strategies to enhance T-DM1 clinical efficacy by combining T-DM1 and other inhibitors that target signaling transduction or resistance pathways. Mol Cancer Ther; 17(7); 1441–53. ©2018 AACR.
Data from Single-Molecule Supercoil Relaxation Assay as a Screening Tool to Determine the Mechanism and Efficacy of Human Topoisomerase IB Inhibitors
Authors: Seol Yeonee , Zhang Hongliang , Agama Keli , Lorence Nicholas , Pommier Yves , Neuman Keir C.
Published: April 2023

Abstract
Human nuclear type IB topoisomerase (Top1) inhibitors are widely used and powerful anticancer agents. In this study, we introduce and validate a single-molecule supercoil relaxation assay as a molecular pharmacology tool for characterizing therapeutically relevant Top1 inhibitors. Using this assay, we determined the effects on Top1 supercoil relaxation activity of four Top1 inhibitors; three clinically relevant: camptothecin, LMP-400, LMP-776 (both indenoisoquinoline derivatives), and one natural product in preclinical development, lamellarin-D. Our results demonstrate that Top1 inhibitors have two distinct effects on Top1 activity: a decrease in supercoil relaxation rate and an increase in religation inhibition. The type and magnitude of the inhibition mode depend both on the specific inhibitor and on the topology of the DNA substrate. In general, the efficacy of inhibition is significantly higher with supercoiled than with relaxed DNA substrates. Comparing single-molecule inhibition with cell growth inhibition (IC50) measurements showed a correlation between the binding time of the Top1 inhibitors and their cytotoxic efficacy, independent of the mode of inhibition. This study demonstrates that the single-molecule supercoil relaxation assay is a sensitive method to elucidate the detailed mechanisms of Top1 inhibitors and is relevant for the cellular efficacy of Top1 inhibitors. Mol Cancer Ther; 14(11); 2552–9. ©2015 AACR.
Data from 17-Hydroxy Wortmannin Restores TRAIL's Response by Ameliorating Increased Beclin 1 Level and Autophagy Function in TRAIL-Resistant Colon Cancer Cells
Authors: Dai Sheng , Yang Shu , Hu Xin , Sun Wei , Tawa Gregory , Zhu Wenge , Schimmer Aaron D. , He Chao , Fang Bingliang , Zhu Hongbo , Zheng Wei
Published: April 2023

Abstract
Targeting of extrinsic apoptosis pathway by TNF-related apoptosis-inducing ligand (TRAIL) is an attractive approach for cancer therapy. However, two TRAIL drug candidates failed in clinical trials due to lack of efficacy. We identified 17-hydroxy wortmannin (17-HW) in a drug repurposing screen that resensitized TRAIL's response in the resistant colon cancer cells. The deficiency of caspase-8 in drug-resistant cells along with defects in apoptotic cell death was corrected by 17-HW, an inhibitor of PIK3C3-beclin 1 (BECN1) complex and autophagy activity. Further study found that BECN1 significantly increased in the TRAIL-resistant cells, resulting in increased autophagosome formation and enhanced autophagy flux. The extracellular domain (ECD) of BECN1 directly bound to the caspase-8 catalytic subunit (p10), leading to sequestration of caspase-8 in the autophagosome and its subsequent degradation. Inhibition of BECN1 restored the caspase-8 level and TRAIL's apoptotic response in the resistant colon cancer cells. An analysis of 120 colon cancer patient tissues revealed a correlation of a subgroup of patients (30.8%, 37/120) who have high BECN1 level and low caspase-8 level with a poor survival rate. Our study demonstrates that the increased BECN1 accompanied by enhanced autophagy activity is responsible for the TRAIL resistance, and a combination of TRAIL with a PIK3C3-BECN1 inhibitor is a promising therapeutic approach for the treatment of colon cancer.
Data from Dual Inhibition of Hedgehog and c-Met Pathways for Pancreatic Cancer Treatment
Authors: Rucki Agnieszka A. , Xiao Qian , Muth Stephen , Chen Jianlin , Che Xu , Kleponis Jennifer , Sharma Rajni , Anders Robert A. , Jaffee Elizabeth M. , Zheng Lei
Published: April 2023

Abstract
Pancreatic ductal adenocarcinoma (PDAC) is one of the most chemotherapy- and radiotherapy-resistant tumors. The c-Met and Hedgehog (Hh) pathways have been shown previously by our group to be key regulatory pathways in the primary tumor growth and metastases formation. Targeting both the HGF/c-Met and Hh pathways has shown promising results in preclinical studies; however, the benefits were not readily translated into clinical trials with PDAC patients. In this study, utilizing mouse models of PDAC, we showed that inhibition of either HGF/c-Met or Hh pathways sensitize the PDAC tumors to gemcitabine, resulting in decreased primary tumor volume as well as significant reduction of metastatic tumor burden. However, prolonged treatment of single HGF/c-Met or Hh inhibitor leads to resistance to these single inhibitors, likely because the single c-Met treatment leads to enhanced expression of Shh, and vice versa. Targeting both the HGF/c-Met and Hh pathways simultaneously overcame the resistance to the single-inhibitor treatment and led to a more potent antitumor effect in combination with the chemotherapy treatment. Mol Cancer Ther; 16(11); 2399–409. ©2017 AACR.
Data from Sulindac Modulates the Response of Proficient MMR Colorectal Cancer to Anti–PD-L1 Immunotherapy
Authors: Yi Bin , Cheng Hao , Wyczechowska Dorota , Yu Qingzhao , Li Li , Ochoa Augusto C. , Riker Adam I. , Xi Yaguang
Published: April 2023

Abstract
Immune-checkpoint inhibitor (ICI) therapy has been widely used to treat different human cancers, particularly advanced solid tumors. However, clinical studies have reported that ICI immunotherapy benefits only ∼15% of patients with colorectal cancer, specifically those with tumors characterized by microsatellite instability (MSI), a molecular marker of defective DNA mismatch repair (dMMR). For the majority of patients with colorectal cancer who carry proficient MMR (pMMR), ICIs have shown little clinical benefit. In this study, we examined the efficacy of sulindac to enhance the response of pMMR colorectal cancer to anti–PD-L1 immunotherapy. We utilized a CT26 syngeneic mouse tumor model to compare the inhibitory effects of PD-L1 antibody (Ab), sulindac, and their combination on pMMR colorectal cancer tumor growth. We found that mice treated with combination therapy showed a significant reduction in tumor volume, along with increased infiltration of CD8+ T lymphocytes in the tumor tissues. We also demonstrated that sulindac could downregulate PD-L1 by blocking NF-κB signaling, which in turn led to a decrease in exosomal PD-L1. Notably, PD-L1 Ab can be bound and consumed by exosomal PD-L1 in the blood circulation. Therefore, in combination therapy, sulindac downregulating PD-L1 leads to increased availability of PD-L1 Ab, which potentially improves the overall efficacy of anti–PD-L1 therapy. We also show that low-dose sulindac does not appear to have a systemic inhibitory effect on prostaglandin E2 (PGE2). In conclusion, our findings provide unique insights into the mechanism of action and efficacy for sulindac as an immunomodulatory agent in combination with anti–PD-L1 therapy for the treatment of pMMR colorectal cancer.
Data from Metabolic Profiling in Formalin-Fixed and Paraffin-Embedded Prostate Cancer Tissues
Authors: Cacciatore Stefano , Zadra Giorgia , Bango Clyde , Penney Kathryn L. , Tyekucheva Svitlana , Yanes Oscar , Loda Massimo
Published: April 2023

Abstract
Metabolite profiling has significantly contributed to a deeper understanding of the biochemical metabolic networks and pathways in cancer cells. Metabolomics-based biomarker discovery would greatly benefit from the ability to interrogate retrospective annotated clinical specimens archived as formalin-fixed, paraffin-embedded (FFPE) material. Mass spectrometry–based metabolomic analysis was performed in matched frozen and FFPE human prostate cancers as well as isogenic prostate cancer cell lines. A total of 352 and 460 metabolites were profiled in human tissues and cell lines, respectively. Classes and physical–chemical characteristics of the metabolites preserved in FFPE material were characterized and related to their preservation or loss following fixation and embedding. Metabolite classes were differentially preserved in archival FFPE tissues, regardless of the age of the block, compared with matched frozen specimen, ranging from maximal preservation of fatty acids (78%) to loss of the majority of peptides and steroids. Generally, FFPE samples showed a decrease of metabolites with functional groups, such as carboxamide. As an adjunct technique, metabolic profiles were also obtained in situ from FFPE tissue sections where metabolites were extracted in a manner that preserves tissue architecture. Despite the fact that selected metabolites were not retained after processing, global metabolic profiles obtained from FFPE can be used to predict biologic states and study biologic pathways. These results pave the way for metabolomics-based biomarker discovery/validation utilizing retrospective and clinically annotated FFPE collections.

Implications: Metabolic profiles can be performed in archival tissue and may be used to complement other profiling methods such as gene expression for biomarker discovery or pathway analysis in the assessment of biologic states. Mol Cancer Res; 15(4); 439–47. ©2017 AACR.