bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from BRCA1 through Its E3 Ligase Activity Regulates the Transcription Factor Oct1 and Carbohydrate Metabolism
Authors: Vázquez-Arreguín Karina , Maddox Jessica , Kang Jinsuk , Park Dongju , Cano Reuben R. , Factor Rachel E. , Ludwig Thomas , Tantin Dean
Published: April 2023

Abstract
The tumor suppressor BRCA1 regulates the DNA damage response (DDR) and other processes that remain incompletely defined. Among these, BRCA1 heterodimerizes with BARD1 to ubiquitylate targets via its N-terminal E3 ligase activity. Here, it is demonstrated that BRCA1 promotes oxidative metabolism by degrading Oct1 (POU2F1), a transcription factor with proglycolytic and tumorigenic effects. BRCA1 E3 ubiquitin ligase mutation skews cells toward a glycolytic metabolic profile while elevating Oct1 protein. CRISPR-mediated Oct1 deletion reverts the glycolytic phenotype. RNA sequencing (RNAseq) confirms deregulation of metabolic genes downstream of Oct1. BRCA1 mediates Oct1 ubiquitylation and degradation, and mutation of two ubiquitylated Oct1 lysines insulates the protein against BRCA1-mediated destabilization. Oct1 deletion in MCF-7 breast cancer cells does not perturb growth in standard culture, but inhibits growth in soft agar and xenograft assays. In primary breast cancer clinical specimens, Oct1 protein levels correlate positively with tumor aggressiveness and inversely with BRCA1. These results identify BRCA1 as an Oct1 ubiquitin ligase that catalyzes Oct1 degradation to promote oxidative metabolism and restrict tumorigenicity. Mol Cancer Res; 16(3); 439–52. ©2018 AACR.
Data from Cholesterol Esterification Inhibition Suppresses Prostate Cancer Metastasis by Impairing the Wnt/β-catenin Pathway
Authors: Lee Hyeon Jeong , Li Jie , Vickman Renee E. , Li Junjie , Liu Rui , Durkes Abigail C. , Elzey Bennett D. , Yue Shuhua , Liu Xiaoqi , Ratliff Timothy L. , Cheng Ji-Xin
Published: April 2023

Abstract
Dysregulation of cholesterol is a common characteristic of human cancers including prostate cancer. This study observed an aberrant accumulation of cholesteryl ester in metastatic lesions using Raman spectroscopic analysis of lipid droplets in human prostate cancer patient tissues. Inhibition of cholesterol esterification in prostate cancer cells significantly suppresses the development and growth of metastatic cancer lesions in both orthotopic and intracardiac injection mouse models. Gene expression profiling reveals that cholesteryl ester depletion suppresses the metastatic potential through upregulation of multiple regulators that negatively impact metastasis. In addition, Wnt/β-catenin, a vital pathway for metastasis, is downregulated upon cholesteryl ester depletion. Mechanistically, inhibition of cholesterol esterification significantly blocks secretion of Wnt3a through reduction of monounsaturated fatty acid levels, which limits Wnt3a acylation. These results collectively validate cholesterol esterification as a novel metabolic target for treating metastatic prostate cancer. Mol Cancer Res; 16(6); 974–85. ©2018 AACR.
Data from Loss of TP63 Promotes the Metastasis of Head and Neck Squamous Cell Carcinoma by Activating MAPK and STAT3 Signaling
Authors: Lakshmanachetty Senthilnath , Balaiya Velmurugan , High Whitney A. , Koster Maranke I.
Published: April 2023

Abstract
TP63 is frequently amplified or overexpressed in primary head and neck squamous cell carcinomas (HNSCC). Nevertheless, the role of TP63 in the initiation and progression of HNSCCs is not known. Using archival HNSCC tissue sections, we found that TP63 expression is often downregulated in late-stage human HNSCCs. To establish a causal link between TP63 loss and HNSCC tumorigenesis, we developed a genetically engineered mouse model in which Trp63 (the mouse homolog of human TP63) was ablated from head and neck epithelia. Upon exposure of the mice to a chemical carcinogen, we found that Trp63 ablation accelerated HNSCC initiation and progression. To determine whether these findings are relevant for human HNSCCs, we generated TP63 knockdown HNSCC cell lines. These cells were implanted into the tongue of athymic nude mice to generate orthotopic xenografts. We found that loss of TP63 promoted HNSCC progression and metastasis. Furthermore, we determined that tumor metastasis is dependent on MAPK activation in TP63 knockdown HNSCCs. The significance of these findings is underscored by our finding that pharmacologic inhibition of MAPK activity by trametinib drastically impaired HNSCC metastasis mediated by TP63 loss. In conclusion, our data provide novel mechanistic insights into the role of TP63 loss in HNSCC initiation and progression, and provide a rationale for the development of new therapeutic approaches specifically targeting TP63-dependent tumor pathways.
Implications:
Our findings uncover a novel functional role for TP63 loss in HNSCC metastasis and identify MAPK signaling as a potential therapeutic target for treating HNSCCs with low TP63 expression.
Data from Loss of Uracil DNA Glycosylase Selectively Resensitizes p53-Mutant and -Deficient Cells to 5-FdU
Authors: Yan Yan , Qing Yulan , Pink John J. , Gerson Stanton L.
Published: April 2023

Abstract
Thymidylate synthase (TS) inhibitors including fluoropyrimidines [e.g., 5-Fluorouracil (5-FU) and 5-Fluorodeoxyuridine (5-FdU, floxuridine)] and antifolates (e.g., pemetrexed) are widely used against solid tumors. Previously, we reported that shRNA-mediated knockdown (KD) of uracil DNA glycosylase (UDG) sensitized cancer cells to 5-FdU. Because p53 has also been shown as a critical determinant of the sensitivity to TS inhibitors, we further interrogated 5-FdU cytotoxicity after UDG depletion with regard to p53 status. By analyzing a panel of human cancer cells with known p53 status, it was determined that p53-mutated or -deficient cells are highly resistant to 5-FdU. UDG depletion resensitizes 5-FdU in p53-mutant and -deficient cells, whereas p53 wild-type (WT) cells are not affected under similar conditions. Utilizing paired HCT116 p53 WT and p53 knockout (KO) cells, it was shown that loss of p53 improves cell survival after 5-FdU, and UDG depletion only significantly sensitizes p53 KO cells. This sensitization can also be recapitulated by UDG depletion in cells with p53 KD by shRNAs. In addition, sensitization is also observed with pemetrexed in p53 KO cells, but not with 5-FU, most likely due to RNA incorporation. Importantly, in p53 WT cells, the apoptosis pathway induced by 5-FdU is activated independent of UDG status. However, in p53 KO cells, apoptosis is compromised in UDG-expressing cells, but dramatically elevated in UDG-depleted cells. Collectively, these results provide evidence that loss of UDG catalyzes significant cell death signals only in cancer cells mutant or deficient in p53.

Implications: This study reveals that UDG depletion restores sensitivity to TS inhibitors and has chemotherapeutic potential in the context of mutant or deficient p53. Mol Cancer Res; 16(2); 212–21. ©2017 AACR.
Data from SOX9/FXYD3/Src Axis Is Critical for ER+ Breast Cancer Stem Cell Function
Authors: Xue Yue , Lai Lihua , Lian Wenwen , Tu Xintao , Zhou Jiaojiao , Dong Ping , Su Dan , Wang Xiaojia , Cao Xuetao , Chen Yiding , Wang Qingqing
Published: April 2023

Abstract
The presence of cancer stem cells (CSC), which possess the ability of self-renewal and cancer initiation, is correlated with poor prognosis and drug resistance of breast cancer patients. But the molecular regulatory networks for maintenance of CSC function still remain unclear. Here, we identified that an estrogen-inducible gene FXYD3, whose expression is significantly upregulated in ER+ breast CSCs, is a critical player for regulating ER+ breast CSC function. FXYD3 amplification is crucial in mediating tamoxifen resistance in ER+ breast cancer cells. Interestingly, we also find that stem cell–related transcription factor SOX9 directly promotes FXYD3 expression, and FXYD3 is indispensable for SOX9 nucleus localization, thus forming a positive regulatory feedback loop for FXYD3 amplification and function. In terms of mechanism, FXYD3 interacts with Src and ERα to form an activated complex and triggers Src to transduce nongenomic estrogen signaling for facilitating ER+ breast CSCs. Collectively, these results establish a critical role for SOX9/FXYD3/Src axis in boosting nongenomic estrogen signaling and SOX9 nucleus entry, which is required for maintenance of ER+ breast CSCs and endocrine resistance. Targeting FXYD3-mediated pathway might be a promising therapeutic strategy for hormone therapy–refractory ER+ breast cancer.
Implications:
SOX9/FXYD3/Src axis is critical for promoting CSC function and tamoxifen resistance in ER+ breast cancer.
Data from Polycomb-like Protein 3 Induces Proliferation and Drug Resistance in Multiple Myeloma and Is Regulated by miRNA-15a
Authors: Yu Tengteng , Du Chenxing , Ma Xiaoke , Sui Weiwei , Yu Zhen , Liu Lanting , Zhao Lei , Li Zhongqing , Xu Jie , Wei Xiaojing , Zhou Wen , Deng Shuhui , Zou Dehui , An Gang , Tai Yu-Tzu , Tricot Guido , Anderson Kenneth C. , Qiu Lugui , Zhan Fenghuang , Hao Mu
Published: April 2023

Abstract
Multiple myeloma remains incurable due to the persistence of a minor population of multiple myeloma cells that exhibit drug resistance, which leads to relapsed and/or refractory multiple myeloma. Elucidating the mechanism underlying drug resistance and developing an effective treatment are critical for clinical management of multiple myeloma. Here we showed that promoting expression of the gene for polycomb-like protein 3 (PHF19) induced multiple myeloma cell growth and multidrug resistance in vitro and in vivo. PHF19 was overexpressed in high-risk and drug-resistant primary cells from patients. High levels of PHF19 were correlated with inferior survival of patients with multiple myeloma, in the Total Therapy 2 cohort and in the Intergroup Francophone du Myeloma (IFM) cohort. Enhancing PHF19 expression levels increased Bcl-xL, Mcl-1, and HIF-1a expression in multiple myeloma cells. PHF19 also bound directly with EZH2 and promoted the phosphorylation of EZH2 through PDK1/AKT signaling. miR-15a is a small noncoding RNA that targeted the 3′UTR of PHF19. We found that downregulation of miR-15a led to high levels of PHF19 in multiple myeloma cells. These findings revealed that PHF19 served a crucial role in multiple myeloma proliferation and drug resistance and suggested that the miR-15a/PHF19/EZH2 pathway made a pivotal contribution to multiple myeloma pathogenesis, offering a promising approach to multiple myeloma treatment.
Implications:
Our findings identify that PHF19 mediates EZH2 phosphorylation as a mechanism of myeloma cell drug resistance, providing a rationale to explore therapeutic potential of targeting PHF19 in relapsed or refractory patients with multiple myeloma.
Data from The Th9 Axis Reduces the Oxidative Stress and Promotes the Survival of Malignant T Cells in Cutaneous T-Cell Lymphoma Patients
Authors: Kumar Sushant , Dhamija Bhavuk , Marathe Soumitra , Ghosh Sarbari , Dwivedi Alka , Karulkar Atharva , Sharma Neha , Sengar Manju , Sridhar Epari , Bonda Avinash , Thorat Jayashree , Tembhare Prashant , Shet Tanuja , Gujral Sumeet , Bagal Bhausaheb , Laskar Siddhartha , Jain Hasmukh , Purwar Rahul
Published: April 2023

Abstract
Immune dysfunction is critical in pathogenesis of cutaneous T-cell lymphoma (CTCL). Few studies have reported abnormal cytokine profile and dysregulated T-cell functions during the onset and progression of certain types of lymphoma. However, the presence of IL9-producing Th9 cells and their role in tumor cell metabolism and survival remain unexplored. With this clinical study, we performed multidimensional blood endotyping of CTCL patients before and after standard photo/chemotherapy and revealed distinct immune hallmarks of the disease. Importantly, there was a higher frequency of “skin homing” Th9 cells in CTCL patients with early (T1 and T2) and advanced-stage disease (T3 and T4). However, advanced-stage CTCL patients had severely impaired frequency of skin-homing Th1 and Th17 cells, indicating attenuated immunity. Treatment of CTCL patients with standard photo/chemotherapy decreased the skin-homing Th9 cells and increased the Th1 and Th17 cells. Interestingly, T cells of CTCL patients express IL9 receptor (IL9R), and there was negligible IL9R expression on T cells of healthy donors. Mechanistically, IL9/IL9R interaction on CD3+ T cells of CTCL patients and Jurkat cells reduced oxidative stress, lactic acidosis, and apoptosis and ultimately increased their survival. In conclusion, coexpression of IL9 and IL9R on T cells in CTCL patients indicates the autocrine-positive feedback loop of Th9 axis in promoting the survival of malignant T cells by reducing the oxidative stress.
Implications:
The critical role of Th9 axis in CTCL pathogenesis indicates that strategies targeting Th9 cells might harbor significant potential in developing robust CTCL therapy.
Data from Targeted Inactivation of HDAC2 Restores p16INK4a Activity and Exerts Antitumor Effects on Human Gastric Cancer
Authors: Kim Jeong Kyu , Noh Ji Heon , Eun Jung Woo , Jung Kwang Hwa , Bae Hyun Jin , Shen Qingyu , Kim Min Gyu , Chang Young Gyoon , Kim Seung-Jin , Park Won Sang , Lee Jung Young , Borlak Jürgen , Nam Suk Woo
Published: April 2023

Abstract
Aberrant regulation of histone deacetylase 2 (HDAC2) was reported for gastric cancers. However, responsive cancer genes in disease onset and progression are less understood. HDAC2 expression was studied by quantitative RT-PCR and Western blotting. The functional consequences of HDAC2 knockdown on cell-cycle regulation, programmed cell death, and gene target identification was investigated by flow cytometry, Western blotting, electron microscopy, anchorage-independent colony formation, and cell migration assay and by whole-genome microarray. Therapeutic efficacy of HDAC2 knockdown was determined in nude mice with small hairpin expressing human gastric cancer cells. Epigenetic regulation of p16INK4a was studied by methylation-specific PCR and chromatin-IP to evidence HDAC2 or acetylated-histone-H4 binding at gene specific promoter sequences. HDAC2 gene and protein expression was significantly upregulated in different histopathologic grades of human gastric cancers and cancer cell lines. HDAC2 inactivation significantly reduced cell motility, cell invasion, clonal expansion, and tumor growth. HDAC2 knockdown-induced G1–S cell cycle arrest and restored activity of p16INK4a and the proapoptotic factors. This treatment caused PARP cleavage and hypophosphorylation of the Rb-protein, repressed cyclinD1, CDK4, and Bcl-2 expression and induced autophagic phenotype, that is, LC3B-II conversion. Some gastric tumors and cancer cells displayed p16INK4a promoter hypermethylation but treatment with 5-aza-deoxycitidine restored activity. With others the methylation status was unchanged. Here, chromatin-IP evidenced HDAC2 binding. Nonetheless, expression of p16INK4a was restored by HDAC2 knockdown with notable histone-H4-acetylation, as determined by chromatin-IP. Thus, p16INK4a is regulated by HDAC2. HDAC2 is a bona fide target for novel molecular therapies in gastric cancers. Mol Cancer Res; 11(1); 62–73. ©2012 AACR.
Data from Ku80-Targeted pH-Sensitive Peptide–PNA Conjugates Are Tumor Selective and Sensitize Cancer Cells to Ionizing Radiation
Authors: Kaplan Alanna R. , Pham Ha , Liu Yanfeng , Oyaghire Stanley , Bahal Raman , Engelman Donald M. , Glazer Peter M.
Published: April 2023

Abstract
The development of therapeutic agents that specifically target cancer cells while sparing healthy tissue could be used to enhance the efficacy of cancer therapy without increasing its toxicity. Specific targeting of cancer cells can be achieved through the use of pH-low insertion peptides (pHLIP), which take advantage of the acidity of the tumor microenvironment to deliver cargoes selectively to tumor cells. We developed a pHLIP–peptide nucleic acid (PNA) conjugate as an antisense reagent to reduce expression of the otherwise undruggable DNA double-strand break repair factor, KU80, and thereby radiosensitize tumor cells. Increased antisense activity of the pHLIP–PNA conjugate was achieved by partial mini-PEG sidechain substitution of the PNA at the gamma position, designated pHLIP-αKu80(γ). We evaluated selective effects of pHLIP-αKu80(γ) in cancer cells in acidic culture conditions as well as in two subcutaneous mouse tumor models. Fluorescently labeled pHLIP-αKu80(γ) delivers specifically to acidic cancer cells and accumulates preferentially in tumors when injected i.v. in mice. Furthermore, pHLIP-αKu80(γ) selectively reduced KU80 expression in cells under acidic conditions and in tumors in vivo. When pHLIP-αKu80(γ) was administered to mice prior to local tumor irradiation, tumor growth was substantially reduced compared with radiation treatment alone. Furthermore, there was no evidence of acute toxicity associated with pHLIP-αKu80(γ) administration to the mice. These results establish pHLIP-αKu80(γ) as a tumor-selective radiosensitizing agent.
Implications:
This study describes a novel agent, pHLIP-αKu80(γ), which combines PNA antisense and pHLIP technologies to selectively reduce the expression of the DNA repair factor KU80 in tumors and confer tumor-selective radiosensitization.
Data from mda-7/IL-24 Expression Inhibits Breast Cancer through Upregulation of Growth Arrest-Specific Gene 3 (gas3) and Disruption of β1 Integrin Function
Authors: Li You-Jun , Liu Guodong , Li Yanmei , Vecchiarelli-Federico Laura M. , Liu Jeff C. , Zacksenhaus Eldad , Shan Sze W. , Yang Burton B. , Li Qi , Dash Rupesh , Fisher Paul B. , Archer Michael C. , Ben-David Yaacov
Published: April 2023

Abstract
Melanoma differentiation-associated gene (MDA)-7)/interleukin (IL)-24, a member of the IL-10 family of cytokines, inhibits growth of various human cancer cells, yet the underlying mechanism is largely unknown. Here, we report that mda-7/IL-24 efficiently suppresses the development of rat mammary tumors in vivo. Microarray analysis for genes differentially expressed in rat mammary tumor cells overexpressing MDA-7/IL-24 compared with those that do not express this cytokine identified growth arrest-specific gene-3 (gas3) as a target for mda-7/IL-24. Upregulation of gas3 by mda-7/IL-24 was STAT3 dependent. Induction of gas3 inhibited attachment and proliferation of tumor cells in vitro and in vivo by inhibiting the interaction of β1 integrin with fibronectin. A mutated GAS3, which is unable to bind β1 integrin, was also unable to inhibit fibronectin-mediated attachment and cell growth both in adherent and suspension cultures, suggesting that GAS3 exerts its effects through interaction with and regulation of β1 integrin. Thus, mda-7/IL-24 inhibits breast cancer growth, at least in part, through upregulation of GAS3 and disruption of β1 integrin function. Importantly, the expression of the mda-7/IL-24 receptor, IL-20R1, is highly correlated with GAS3 expression in human breast cancer (P = 1.02 × 10−9), and the incidence of metastases is significantly reduced in patients with HER2+ breast cancer expressing high-levels of IL-20R1. Together, our results identify a novel MDA-7/IL-24-GAS3-β1integrin–fibronectin signaling pathway that suppresses breast cancer growth and can be targeted for therapy. Mol Cancer Res; 11(6); 593–603. ©2013 AACR.
Data from SOX9 Is Essential for Triple-Negative Breast Cancer Cell Survival and Metastasis
Authors: Ma Yanxia , Shepherd Jonathan , Zhao Dekuang , Bollu Lakshmi Reddy , Tahaney William M. , Hill Jamal , Zhang Yun , Mazumdar Abhijit , Brown Powel H.
Published: April 2023

Abstract
Triple-negative breast cancer (TNBC) has the worst prognosis of all breast cancers, and lacks effective targeted treatment strategies. Previously, we identified 33 transcription factors highly expressed in TNBC. Here, we focused on six sex determining region Y-related HMG-box (SOX) transcription factors (SOX4, 6, 8, 9, 10, and 11) highly expressed in TNBCs. Our siRNA screening assay demonstrated that SOX9 knockdown suppressed TNBC cell growth and invasion in vitro. Thus, we hypothesized that SOX9 is an important regulator of breast cancer survival and metastasis, and demonstrated that knockout of SOX9 reduced breast tumor growth and lung metastasis in vivo. In addition, we found that loss of SOX9 induced profound apoptosis, with only a slight impairment of G1 to S progression within the cell cycle, and that SOX9 directly regulates genes controlling apoptosis. On the basis of published CHIP-seq data, we demonstrated that SOX9 binds to the promoter of apoptosis-regulating genes (tnfrsf1b, fadd, tnfrsf10a, tnfrsf10b, and ripk1), and represses their expression. SOX9 knockdown upregulates these genes, consistent with the induction of apoptosis. Analysis of available CHIP-seq data showed that SOX9 binds to the promoters of several epithelial–mesenchymal transition (EMT)- and metastasis-regulating genes. Using CHIP assays, we demonstrated that SOX9 directly binds the promoters of genes involved in EMT (vim, cldn1, ctnnb1, and zeb1) and that SOX9 knockdown suppresses the expression of these genes.
Implications:
Our studies identified the SOX9 protein as a “master regulator” of breast cancer cell survival and metastasis, and provide preclinical rationale to develop SOX9 inhibitors for the treatment of women with metastatic triple-negative breast cancer.
Data from Inhibition of Akt Potentiates 2-DG–Induced Apoptosis via Downregulation of UPR in Acute Lymphoblastic Leukemia
Authors: DeSalvo Joanna , Kuznetsov Jeffim N. , Du Jianfeng , Leclerc Gilles M. , Leclerc Guy J. , Lampidis Theodore J. , Barredo Julio C.
Published: April 2023

Abstract
The ability to pair the regulation of metabolism and cellular energetics with oncogenes and tumor suppressor genes provides cancer cells with a growth and survival advantage over normal cells. We investigated the mechanism of cell death induced by 2-deoxy-d-glucose (2-DG), a sugar analog with dual activity of inhibiting glycolysis and N-linked glycosylation, in acute lymphoblastic leukemia (ALL). We found that, unlike most other cancer phenotypes in which 2-DG only inhibits cell proliferation under normoxic conditions, ALL lymphoblasts undergo apoptosis. Bp-ALL cell lines and primary cells exhibited sensitivity to 2-DG, whereas T-ALL cells were relatively resistant, revealing phenotypic differences within ALL subtypes. Cotreatment with d-mannose, a sugar essential for N-linked glycosylation, rescues 2-DG–treated ALL cells, indicating that inhibition of N-linked glycosylation and induction of ER stress and the unfolded protein response (UPR) is the predominant mechanism of 2-DG's cytotoxicity in ALL. 2-DG–treated ALL cells exhibit upregulation of P-AMPK, P-Akt, and induction of ER stress/UPR markers (IRE1α, GRP78, P-eIF2α, and CHOP), which correlate with PARP cleavage and apoptosis. In addition, we find that pharmacologic and genetic Akt inhibition upregulates P-AMPK, downregulates UPR, and sensitizes ALL cells to remarkably low doses of 2-DG (0.5 mmol/L), inducing 85% cell death and overcoming the relative resistance of T-ALL. In contrast, AMPK knockdown rescues ALL cells by upregulating the prosurvival UPR signaling. Therefore, 2-DG induces ALL cell death under normoxia by inducing ER stress, and AKT and AMPK, traditionally thought to operate predominantly on the glycolytic pathway, differentially regulate UPR activity to determine cell death or survival. Mol Cancer Res; 10(7); 969–78. ©2012 AACR.
Data from Thrombin Regulates the Metastatic Potential of Human Rhabdomyosarcoma Cells: Distinct Role of PAR1 and PAR3 Signaling
Authors: Wysoczynski Marcin , Liu Rui , Kucia Magda , Drukala Justyna , Ratajczak Mariusz Z.
Published: April 2023

Abstract
We observed that human rhabdomyosarcoma (RMS) cells highly express a tissue factor that promotes thrombin formation, which indirectly and directly affects RMS progression. First, we found that thrombin activates platelets to generate microvesicles (PMV), which transfer to RMS cells' α2β3 integrin and increase their adhesiveness to endothelial cells. Accordingly, RMS cells covered with PMVs showed higher metastatic potential after i.v. injection into immunodeficient mice. Furthermore, PMVs activate mitogen-activated protein kinase (MAPK)p42/44 and AKT to chemoattract RMS cells. We also found that RMS cells express functional protease-activated receptor-1 (PAR1) and PAR3 and respond to thrombin stimulation by MAPKp42/44 and MAPKp38 phosphorylation. To our surprise, thrombin did not affect RMS proliferation or survival; it inhibited the chemotactic and adhesive properties of RMS cells. However, when PAR1-specific agonist thrombin receptor–activating peptide 6 was used, which does not activate PAR3, selective PAR1 stimulation enhanced RMS proliferation. To learn more on the role of PAR1 and PAR3 antagonism in RMS proliferation and metastasis, we knocked down both receptors by using a short hairpin RNA strategy. We found that although thrombin does not affect growth of PAR1−/− cells, it stimulated the proliferation of PAR3−/− cells. More importantly, PAR3−/− cells, in contrast to PAR1−/− ones, formed larger tumors in immunodeficient mice. We conclude that thrombin is a novel underappreciated modulator of RMS metastasis and that we have identified a novel role for PAR3 in thrombin signaling. Mol Cancer Res; 8(5); 677–90. ©2010 AACR.
Data from Aurora-A Overexpression in Mouse Liver Causes p53-Dependent Premitotic Arrest during Liver Regeneration
Authors: Li Chao-Chin , Chu Hui-Yi , Yang Chu-Wen , Chou Chen-Kung , Tsai Ting-Fen
Published: April 2023

Abstract
Aurora-A, a serine-threonine kinase, is frequently overexpressed in human cancers, including hepatocellular carcinoma. To study the phenotypic effects of Aurora-A overexpression on liver regeneration and tumorigenesis, we generated transgenic mice overexpressing human Aurora-A in the liver. The overexpression of Aurora-A after hepatectomy caused an earlier entry into S phase, a sustaining of DNA synthesis, and premitotic arrest in the regenerating liver. These regenerating transgenic livers show a relative increase in binuclear hepatocytes compared with regenerating wild-type livers; in addition, multipolar segregation and trinucleation could be observed only in the transgenic hepatocytes after hepatectomy. These results together suggest that defects accumulated after first round of the hepatocyte cell cycle and that there was a failure to some degree of cytokinesis. Interestingly, the p53-dependent checkpoint was activated by these abnormalities, indicating that p53 plays a crucial role during liver regeneration. Indeed, the premitotic arrest and abnormal cell death, mainly necrosis, caused by Aurora-A overexpression were genetically rescued by p53 knockout. However, trinucleation of hepatocytes remained in the regenerating livers of the transgenic mice with a p53 knockout background, indicating that the abnormal mitotic segregation and cytokinesis failure were p53 independent. Moreover, overexpression of Aurora-A in transgenic liver led to a low incidence (3.8%) of hepatic tumor formation after a long latency period. This transgenic mouse model provides a useful system that allows the study of the physiologic effects of Aurora-A on liver regeneration and the genetic pathways of Aurora-A–mediated tumorigenesis in liver.
Data from Aldehyde Dehydrogenase Discriminates the CD133 Liver Cancer Stem Cell Populations
Authors: Ma Stephanie , Chan Kwok Wah , Lee Terence Kin-Wah , Tang Kwan Ho , Wo Jana Yim-Hung , Zheng Bo-Jian , Guan Xin-Yuan
Published: April 2023

Abstract
Recent efforts in our study of cancer stem cells (CSC) in hepatocellular carcinoma (HCC) have led to the identification of CD133 as a prominent HCC CSC marker. Findings were based on experiments done on cell lines and xenograft tumors where expression of CD133 was detected at levels as high as 65%. Based on the CSC theory, CSCs are believed to represent only a minority number of the tumor mass. This is indicative that our previously characterized CD133+ HCC CSC population is still heterogeneous, consisting of perhaps subsets of cells with differing tumorigenic potential. We hypothesized that it is possible to further enrich the CSC population by means of additional differentially expressed markers. Using a two-dimensional PAGE approach, we compared protein profiles between CD133+ and CD133− subpopulations isolated from Huh7 and PLC8024 and identified aldehyde dehydrogenase 1A1 as one of the proteins that are preferentially expressed in the CD133+ subfraction. Analysis of the expression of several different ALDH isoforms and ALDH enzymatic activity in liver cell lines found ALDH to be positively correlated with CD133 expression. Dual-color flow cytometry analysis found the majority of ALDH+ to be CD133+, yet not all CD133+ HCC cells were ALDH+. Subsequent studies on purified subpopulations found CD133+ALDH+ cells to be significantly more tumorigenic than their CD133−ALDH+ or CD133−ALDH− counterparts, both in vitro and in vivo. These data, combined with those from our previous work, reveal the existence of a hierarchical organization in HCC bearing tumorigenic potential in the order of CD133+ALDH+ > CD133+ALDH− > CD133−ALDH−. ALDH, expressed along CD133, can more specifically characterize the tumorigenic liver CSC population. (Mol Cancer Res 2008;6(7):1146–53)
Data from Tie2 in Tumor Endothelial Signaling and Survival: Implications for Antiangiogenic Therapy
Authors: Tsai Jeff H. , Lee William M.F.
Published: April 2023

Abstract
Signaling through the Tie2 receptor on endothelial cells has been shown to play an important role in normal and pathologic vascular development. We generated K1735 murine melanoma tumor cells that inducibly express soluble Tie2 receptor (Tie2Ex) to study the effects of inhibiting Tie2 signaling on tumor vasculature. Tie2Ex induction rapidly decreased AKT activation but not extracellular signal-regulated kinase (ERK) activation in tumor endothelial cells as detected by immunostaining. This was accompanied by an increase in endothelial cell TUNEL staining but no change in Ki-67 expression. Together with a decrease in the percentage of perfused vessels, this suggested that tumor vessel regression and impaired vascular function rather than angiogenesis inhibition was responsible for the delay in tumor growth following Tie2Ex treatment. However, Tie2Ex failed to inhibit the growth of larger, more established K1735 tumors. These tumors were additionally treated with sorafenib, a multikinase inhibitor that inhibits tumor endothelial cell ERK activation but not AKT activation. Combining Tie2Ex and sorafenib decreased both endothelial cell AKT and ERK activation, decreased endothelial cell survival and proliferation, and significantly inhibited growth of the more established tumors. These studies indicate that activity of specific signaling pathways and prosurvival effects are brought about by Tie2 activation in tumor endothelial cells, and knowledge of the effects of Tie2 inhibition can lead to development of more effective therapeutic regimens for inhibiting tumor neovascularization. (Mol Cancer Res 2009;7(3):300–10)
Data from Atypical Protein Kinase Cι (PKCι) Promotes Metastasis of Esophageal Squamous Cell Carcinoma by Enhancing Resistance to Anoikis via PKCι-SKP2-AKT Pathway
Authors: Liu Shu-Guang , Wang Bo-Shi , Jiang Yan-Yi , Zhang Tong-Tong , Shi Zhi-Zhou , Yang Yang , Yang Yi-Ling , Wang Xiao-Chun , Lin De-Chen , Zhang Yu , Yang Hai , Cai Yan , Zhan Qi-Min , Wang Ming-Rong
Published: April 2023

Abstract
Protein kinase Cι (PKCι) is an atypical PKC isoform and participates in multiple aspects of the transformed phenotype in human cancer cells. We previously reported that frequent amplification and overexpression of PKCι were correlated with lymph node metastasis in primary esophageal squamous cell carcinomas (ESCC). In the present study, short interfering RNA–mediated silencing of PKCι revealed that this enzyme was required for cell migration, invasion, and resistance to anoikis. In vivo experiments showed that PKCι suppression decreased tumor growth in esophageal cancer xenografts and lung metastases in nude mice. At the molecular level, knockdown of PKCι in suspended ESCC cells caused a decrease in S-phase kinase-associated protein 2 (SKP2) that had been reported to promote resistance to anoikis via the PI3K/AKT pathway. AKT phosphorylation was abolished after PKCι suppression, but AKT activation could be refreshed by PKCι upregulation, suggesting that PKCι enhanced cell resistance to anoikis via the PKCι-SKP2-PI3K/AKT pathway. Addition of the proteasome inhibitor MG132 prevented the decrease of SKP2 in PKCι silenced cells, and polyubiquitin-SKP2 was elevated after PKCι depletion, showing that PKCι might regulate the expression of SKP2 through the ubiquitin-proteasome pathway in suspended cells. Furthermore, overexpression of SKP2 in PKCι-downregulated cells restored cell resistance to anoikis. Most importantly, PKCι expression significantly correlated with SKP2 in 133 ESCC tissues (P = 0.031). Taken together, our data show that PKCι promotes tumorigenicity and metastasis of human esophageal cancer and that SKP2 is a candidate downstream effector of PKCι signaling in ESCC. Mol Cancer Res; 9(4); 390–402. ©2011 AACR.
Data from The β1-Integrin–Dependent Function of RECK in Physiologic and Tumor Angiogenesis
Authors: Miki Takao , Shamma Awad , Kitajima Shunsuke , Takegami Yujiro , Noda Makoto , Nakashima Yasuaki , Watanabe Ken-ichiro , Takahashi Chiaki
Published: April 2023

Abstract
Vascular endothelial cells produce considerable amounts of matrix metalloproteinases (MMP), including MMP-2, MMP-9, and membrane type 1 (MT1)–MMP. However, little is known about the regulatory mechanisms of these protease activities exhibited during vascular development. A glycosylphosphatidylinositol-anchored glycoprotein, reversion-inducing cysteine-rich protein with Kazal motifs (RECK), has been shown to attenuate MMP-2 maturation by directly interacting with MT1-MMP. Here, we show that an angiogenic factor angiopoietin-1 induces RECK expression in human umbilical vein endothelial cells (HUVEC), and RECK depletion in these cells results in defective vascular tube formation and cellular senescence. We further observed that RECK depletion downregulates β1-integrin activation, which was associated with decreased autophosphorylation of focal adhesion kinase and increased expression of a cyclin-dependent kinase inhibitor p21CIP1. In agreement, significant downregulation of β1-integrin activity was observed in vascular endothelial cells in Reck−/− mouse embryos. In HUVECs, specific inhibition of MMP-2 significantly antagonized the effect of RECK depletion on β1-integrin signaling, cell proliferation, and tube elongation. Furthermore, we observed that hypervascular tumor-derived cell lines can induce high RECK expression in convoluted vascular endothelial cells, and this in turn supports tumor growth. Targeting RECK specifically in tumor-associated vascular endothelial cells resulted in tumor regression. Therefore, we propose that RECK in tumor vascular endothelial cells can be an interesting target of cancer treatment via abortion of tumor angiogenesis. Mol Cancer Res; 8(5); 665–76. ©2010 AACR.
Data from K-Ras Promotes Angiogenesis Mediated by Immortalized Human Pancreatic Epithelial Cells through Mitogen-Activated Protein Kinase Signaling Pathways
Authors: Matsuo Yoichi , Campbell Paul M. , Brekken Rolf A. , Sung Bokyung , Ouellette Michel M. , Fleming Jason B. , Aggarwal Bharat B. , Der Channing J. , Guha Sushovan
Published: April 2023

Abstract
Activating point mutations in the K-Ras oncogene are among the most common genetic alterations in pancreatic cancer, occurring early in the progression of the disease. However, the function of mutant K-Ras activity in tumor angiogenesis remains poorly understood. Using human pancreatic duct epithelial (HPDE) and K-Ras4BG12V–transformed HPDE (HPDE-KRas) cells, we show that activated K-Ras significantly enhanced the production of angiogenic factors including CXC chemokines and vascular endothelial growth factor (VEGF). Western blot analysis revealed that K-Ras activation promoted the phosphorylation of Raf/mitogen-activated protein kinase kinase-1/2 (MEK1/2) and expression of c-Jun. MEK1/2 inhibitors, U0126 and PD98059, significantly inhibited the secretion of both CXC chemokines and VEGF, whereas the c-Jun NH2-terminal kinase inhibitor SP600125 abrogated only CXC chemokine production. To further elucidate the biological functions of oncogenic K-Ras in promoting angiogenesis, we did in vitro invasion and tube formation assays using human umbilical vein endothelial cells (HUVEC). HUVEC cocultured with HPDE-KRas showed significantly enhanced invasiveness and tube formation as compared with either control (without coculture) or coculture with HPDE. Moreover, SB225002 (a CXCR2 inhibitor) and 2C3 (an anti-VEGF monoclonal antibody) either alone or in a cooperative manner significantly reduced the degree of both Ras-dependent HUVEC invasiveness and tube formation. Similar results were obtained using another pair of immortalized human pancreatic duct–derived cells, E6/E7/st and its oncogenic K-Ras variant, E6/E7/Ras/st. Taken together, our results suggest that angiogenesis is initiated by paracrine epithelial secretion of CXC chemokines and VEGF downstream of activated oncogenic K-Ras, and that this vascular maturation is in part dependent on MEK1/2 and c-Jun signaling. (Mol Cancer Res 2009;7(6):799–808)
Data from IKKβ Overexpression Leads to Pathologic Lesions in Stratified Epithelia and Exocrine Glands and to Tumoral Transformation of Oral Epithelia
Authors: Page Angustias , Cascallana José L. , Casanova M. Llanos , Navarro Manuel , Alameda Josefa P. , Pérez Paloma , Bravo Ana , Ramírez Angel
Published: April 2023

Abstract
Alterations in nuclear factor kappaB (NFκB) signaling have been related with several diseases and importantly also with cancer. Different animal models with increased or diminished NFκB signaling have shown that NFκB subunits and their regulators are relevant to the pathophysiology of different organs and tissues. In particular, both the deletion of the regulatory subunit β of the kinase of the inhibitor of NFκB (IKKβ) and its overexpression in epidermis lead to the development of skin inflammatory diseases not associated with tumoral lesions. In this work, we have studied the consequences of IKKβ overexpression in other organs and tissues. We found that elevated IKKβ levels led to altered development and functionality of exocrine glands (i.e., mammary glands) in transgenic female mice. In oral epithelia, increased IKKβ expression produced lichenoid inflammation with abundant granulocytes, macrophages, and B cells, among other inflammatory cells. This inflammatory phenotype was associated with high incidence of tumoral lesions in oral epithelia, contrary to what was found in skin. Moreover, IKKβ also increased the malignant progression of both spontaneous and experimentally induced oral tumors. These results highlight the importance of IKKβ in epithelial and glandular homeostasis as well as in oral tumorigenesis and open the possibility that IKKβ activity might be implicated in the development of oral cancer in humans. Mol Cancer Res; 9(10); 1329–38. ©2011 AACR.
Data from Caveolin-1 Promotes Autoregulatory, Akt-Mediated Induction of Cancer-Promoting Growth Factors in Prostate Cancer Cells
Authors: Li Likun , Ren Chengzhen , Yang Guang , Goltsov Alexei A. , Tabata Ken-ichi , Thompson Timothy C.
Published: April 2023

Abstract
Caveolin-1 (cav-1) and the cancer-promoting growth factors vascular endothelial growth factor (VEGF), transforming growth factor β1 (TGF-β1), and fibroblast growth factor 2 (FGF2) are often found to be upregulated in advanced prostate cancer and other malignancies. However, the relationship between cav-1 overexpression and growth factor upregulation remains unclear. This report presents, to our knowledge, the first evidence that in prostate cancer cells, a positive autoregulatory feedback loop is established in which VEGF, TGF-β1, and FGF2 upregulate cav-1, and cav-1 expression, in turn, leads to increased levels of VEGF, TGF-β1, and FGF2 mRNA and protein, resulting in enhanced invasive activities of prostate cancer cells, i.e., migration and motility. Our results further show that cav-1–enhanced mRNA stability is a major mechanism underlying the upregulation of these cancer-promoting growth factors, and that PI3-K-Akt signaling is required for forming this positive autoregulatory feedback loop.(Mol Cancer Res 2009;7(11):1781–91)
Data from Oncogenic Activating Mutations Are Associated with Local Copy Gain
Authors: Modrek Barmak , Ge Lin , Pandita Ajay , Lin Eva , Mohan Sankar , Yue Peng , Guerrero Steve , Lin William M. , Pham Thinh , Modrusan Zora , Seshagiri Somasekar , Stern Howard M. , Waring Paul , Garraway Levi A. , Chant John , Stokoe David , Cavet Guy
Published: April 2023

Abstract
Although activating mutations and gains in copy number are key mechanisms for oncogene activation, the relationship between the two is not well understood. In this study, we focused on KRAS copy gains and mutations in non–small cell lung cancer. We found that KRAS copy gains occur more frequently in tumors with KRAS activating mutations and are associated with large increases in KRAS expression. These copy gains tend to be more focal in tumors with activating mutations than in those with wild-type KRAS. Fluorescence in situ hybridization analysis revealed that some tumors have homogeneous low-level gains of the KRAS locus, whereas others have high-level amplification of KRAS, often in only a fraction of tumor cells. Associations between activating mutation and copy gains were also observed for other oncogenes (EGFR in non–small cell lung cancer, BRAF and NRAS in melanoma). Activating mutations were associated with copy gains only at the mutated oncogene locus but not other oncogene loci. However, KRAS activating mutations in colorectal cancer were not associated with copy gains. Future work is warranted to clarify the relationship among the different mechanisms of oncogene activation. (Mol Cancer Res 2009;7(8):1244–52)
Data from miRNA-223 Promotes Gastric Cancer Invasion and Metastasis by Targeting Tumor Suppressor EPB41L3
Authors: Li Xiaohua , Zhang Ying , Zhang Hongwei , Liu Xiaonan , Gong Taiqian , Li Mengbin , Sun Li , Ji Gang , Shi Yongquan , Han Zheyi , Han Shuang , Nie Yongzhang , Chen Xiong , Zhao Qinchuan , Ding Jie , Wu Kaichun , Daiming Fan
Published: April 2023

Abstract
Traditional research modes aim to find cancer-specific single therapeutic target. Recently, emerging evidence suggested that some micro-RNAs (miRNA) can function as oncogenes or tumor suppressors. miRNAs are single-stranded, small noncoding RNA genes that can regulate hundreds of downstream target genes. In this study, we evaluated the miRNA expression patterns in gastric carcinoma and the specific role of miR-223 in gastric cancer metastasis. miRNA expression signature was first analyzed by real-time PCR on 10 paired gastric carcinomas and confirmed in another 20 paired gastric carcinoma tissues. With the 2-fold expression difference as a cutoff level, we identified 22 differential expressed mature miRNAs. Sixteen miRNAs were upregulated in gastric carcinoma, including miR-223, miR-21, miR-23b, miR-222, miR-25, miR-23a, miR-221, miR-107, miR-103, miR-99a, miR-100, miR-125b, miR-92, miR-146a, miR-214 and miR-191, and six miRNAs were downregulated in gastric carcinoma, including let-7a, miR-126, miR-210, miR-181b, miR-197, and miR-30aa-5p. After examining these miRNAs in several human gastric originated cell lines, we found that miR-223 is overexpressed only in metastatic gastric cancer cells and stimulated nonmetastatic gastric cancer cells migration and invasion. Mechanistically, miR-223, induced by the transcription factor Twist, posttranscriptionally downregulates EPB41L3 expression by directly targeting its 3′-untranslated regions. Significantly, overexpression of miR-223 in primary gastric carcinomas is associated with poor metastasis-free survival. These findings indicate a new regulatory mode, namely, specific miRNA, which is activated by its upstream transcription factor, could suppress its direct targets and lead to tumor invasion and metastasis. Mol Cancer Res; 9(7); 824–33. ©2011 AACR.
Data from CXCR4 Promotes Oral Squamous Cell Carcinoma Migration and Invasion through Inducing Expression of MMP-9 and MMP-13 via the ERK Signaling Pathway
Authors: Yu Tao , Wu Yingying , Helman Joseph I. , Wen Yuming , Wang Changmei , Li Longjiang
Published: April 2023

Abstract
The increased migration and invasion of oral squamous cell carcinoma cells are key events in the development of metastasis to the lymph nodes and distant organs. Although the chemokine receptor CXCR4 and its ligand, stromal cell–derived factor-1α, have been found to play an important role in tumor invasion, its precise role and potential underlying mechanisms remain largely unknown. In this study, we showed that knockdown of CXCR4 significantly decreased Tca8113 cells migration and invasion, accompanied with the reduction of MMP-9 and MMP-13 expression. Inhibition of ligand binding to CXCR4 by a specific antagonist TN14003, also led to reduced cancer cell migration and invasion. Because the degradation of the extracellular matrix and the basement membrane by proteases, such as matrix metalloproteinases (MMP) is critical for migration and invasion of cancer cells, we investigated the expression of several MMPs and found that the expression of functional MMP-9 and MMP-13 was selectively decreased in CXCR4 knockdown cells. More importantly, decreased cell migration and invasion of CXCR4 knockdown cells were completely rescued by exogenous expression of MMP-9 or MMP-13, indicating that the two MMPs are downstream targets of CXCR4-mediated signaling. Furthermore, we found the level of phosphorylated extracellular signal-regulated kinase (ERK) was significantly decreased in CXCR4-silenced cells, suggesting that ERK may be a potential mediator of CXCR4-regulated MMP-9 and MMP-13 expression in Tca8113 cells. Taken together, our results strongly suggest the underlying mechanism of CXCR4 promoting Tca8113 migration and invasion by regulating MMP-9 and MMP-13 expression perhaps via activation of the ERK signaling pathway. Mol Cancer Res; 9(2); 161–72. ©2011 AACR.
Data from Down-Regulation of 3-Phosphoinositide–Dependent Protein Kinase-1 Levels Inhibits Migration and Experimental Metastasis of Human Breast Cancer Cells
Authors: Liu Ying , Wang Jingna , Wu Min , Wan Wuzhou , Sun Ronghua , Yang De , Sun Xiangjun , Ma Dalong , Ying Guoguang , Zhang Ning
Published: April 2023

Abstract
High expression of 3-phosphoinositide–dependent protein kinase-1 (PDK1) has been detected in various invasive cancers. In the current study, we investigated its role in cancer cell migration and experimental metastasis. Down-regulation of PDK1 expression by small interference RNA markedly inhibited spontaneous migration and epidermal growth factor (EGF)–induced chemotaxis of human breast cancer cells. The defects were rescued by expressing wild-type PDK1. PDK1-depleted cells showed impaired EGF-induced actin polymerization and adhesion, probably due to a decrease in phosphorylation of LIM kinase/cofilin and integrin β1. Confocal microscopy revealed that EGF induced cotranslocation of PDK1 with Akt and protein kinase Cζ (PKCζ), regulators of LIM kinase, and integrin β1. Furthermore, PDK1 depletion dampened EGF-induced phosphorylation and translocation of Akt and PKCζ, suggesting that Akt and PKCζ functioned downstream of PDK1 in the chemotactic signaling pathway. In severe combined immunodeficiency mice, PDK1-depleted human breast cancer cells formed more slowly growing tumors and were defective in extravasation to mouse lungs after i.v. injection. Our results indicate that PDK1 plays an important role in regulating the malignant behavior of breast cancer cells, including their motility, through activation of Akt and PKCζ. Thus, PDK1, which increases its expression in cancer cells, can be used as a target for the development of novel therapies. (Mol Cancer Res 2009;7(6):944–54)