bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from c-MYC Drives Breast Cancer Metastasis to the Brain, but Promotes Synthetic Lethality with TRAIL
Authors: Lee Ho Yeon , Cha Junghwa , Kim Seon Kyu , Park Jun Hyung , Song Ki Hoon , Kim Pilnam , Kim Mi-Young
Published: March 2024

Abstract
Brain metastasis in breast cancer is particularly deadly, but effective treatments remain out of reach due to insufficient information about the mechanisms underlying brain metastasis and the potential vulnerabilities of brain-metastatic breast cancer cells. Here, human breast cancer cells and their brain-metastatic derivatives (BrMs) were used to investigate synthetic lethal interactions in BrMs. First, it was demonstrated that c-MYC activity is increased in BrMs and is required for their brain-metastatic ability in a mouse xenograft model. Specifically, c-MYC enhanced brain metastasis by facilitating the following processes within the brain microenvironment: (i) invasive growth of BrMs, (ii) macrophage infiltration, and (iii) GAP junction formation between BrMs and astrocytes by upregulating connexin 43 (GJA1/Cx43). Furthermore, RNA-sequencing (RNA-seq) analysis uncovered a set of c-MYC–regulated genes whose expression is associated with higher risk for brain metastasis in breast cancer patients. Paradoxically, however, increased c-MYC activity in BrMs rendered them more susceptible to TRAIL (TNF-related apoptosis-inducing ligand)–induced apoptosis. In summary, these data not only reveal the brain metastasis-promoting role of c-MYC and a subsequent synthetic lethality with TRAIL, but also delineate the underlying mechanism. This suggests TRAIL-based approaches as potential therapeutic options for brain-metastatic breast cancer.
Implications:
This study discovers a paradoxical role of c-MYC in promoting metastasis to the brain and in rendering brain-metastatic cells more susceptible to TRAIL, which suggests the existence of an Achilles' heel, thus providing a new therapeutic opportunity for breast cancer patients.
Data from Epigenetic Targeting of Adipocytes Inhibits High-Grade Serous Ovarian Cancer Cell Migration and Invasion
Authors: Tang Jessica , Pulliam Nicholas , Özeş Ali , Buechlein Aaron , Ding Ning , Keer Harold , Rusch Doug , O'Hagan Heather , Stack M. Sharon , Nephew Kenneth P.
Published: March 2024

Abstract
Ovarian cancer (OC) cells frequently metastasize to the omentum, and adipocytes play a significant role in ovarian tumor progression. Therapeutic interventions targeting aberrant DNA methylation in ovarian tumors have shown promise in the clinic, but the effects of epigenetic therapy on the tumor microenvironment are understudied. Here, we examined the effect of adipocytes on OC cell behavior in culture and impact of targeting DNA methylation in adipocytes on OC metastasis. The presence of adipocytes increased OC cell migration and invasion, and proximal and direct coculture of adipocytes increased OC proliferation alone or after treatment with carboplatin. Treatment of adipocytes with hypomethylating agent guadecitabine decreased migration and invasion of OC cells toward adipocytes. Subcellular protein fractionation of adipocytes treated with guadecitabine revealed decreased DNA methyltransferase 1 (DNMT1) levels even in the presence of DNA synthesis inhibitor, aphidicolin. Methyl-Capture- and RNA-sequencing analysis of guadecitabine-treated adipocytes revealed derepression of tumor-suppressor genes and epithelial–mesenchymal transition inhibitors. SUSD2, a secreted tumor suppressor downregulated by promoter CpG island methylation in adipocytes, was upregulated after guadecitabine treatment, and recombinant SUSD2 decreased OC cell migration and invasion. Integrated analysis of the methylomic and transcriptomic data identified pathways associated with inhibition of matrix metalloproteases and fatty acid α-oxidation, suggesting a possible mechanism of how epigenetic therapy of adipocytes decreases metastasis. In conclusion, the effect of DNMT inhibitor on fully differentiated adipocytes suggests that hypomethylating agents may affect the tumor microenvironment to decrease cancer cell metastasis.

Implications: Epigenetic targeting of tumor microenvironment can affect metastatic behavior of ovarian cancer cells. Mol Cancer Res; 16(8); 1226–40. ©2018 AACR.
Data from Lipid Uptake Is an Androgen-Enhanced Lipid Supply Pathway Associated with Prostate Cancer Disease Progression and Bone Metastasis
Authors: Tousignant Kaylyn D. , Rockstroh Anja , Taherian Fard Atefeh , Lehman Melanie L. , Wang Chenwei , McPherson Stephen J. , Philp Lisa K. , Bartonicek Nenad , Dinger Marcel E. , Nelson Colleen C. , Sadowski Martin C.
Published: March 2024

Abstract
De novo lipogenesis is a well-described androgen receptor (AR)–regulated metabolic pathway that supports prostate cancer tumor growth by providing fuel, membrane material, and steroid hormone precursor. In contrast, our current understanding of lipid supply from uptake of exogenous lipids and its regulation by AR is limited, and exogenous lipids may play a much more significant role in prostate cancer and disease progression than previously thought. By applying advanced automated quantitative fluorescence microscopy, we provide the most comprehensive functional analysis of lipid uptake in cancer cells to date and demonstrate that treatment of AR-positive prostate cancer cell lines with androgens results in significantly increased cellular uptake of fatty acids, cholesterol, and low-density lipoprotein particles. Consistent with a direct, regulatory role of AR in this process, androgen-enhanced lipid uptake can be blocked by the AR-antagonist enzalutamide, but is independent of proliferation and cell-cycle progression. This work for the first time comprehensively delineates the lipid transporter landscape in prostate cancer cell lines and patient samples by analysis of transcriptomics and proteomics data, including the plasma membrane proteome. We show that androgen exposure or deprivation regulates the expression of multiple lipid transporters in prostate cancer cell lines and tumor xenografts and that mRNA and protein expression of lipid transporters is enhanced in bone metastatic disease when compared with primary, localized prostate cancer. Our findings provide a strong rationale to investigate lipid uptake as a therapeutic cotarget in the fight against advanced prostate cancer in combination with inhibitors of lipogenesis to delay disease progression and metastasis.
Implications:
Prostate cancer exhibits metabolic plasticity in acquiring lipids from uptake and lipogenesis at different disease stages, indicating potential therapeutic benefit by cotargeting lipid supply.
Data from HILPDA Regulates Lipid Metabolism, Lipid Droplet Abundance, and Response to Microenvironmental Stress in Solid Tumors
Authors: VandeKopple Matthew J. , Wu Jinghai , Auer Erich N. , Giaccia Amato J. , Denko Nicholas C. , Papandreou Ioanna
Published: March 2024

Abstract
Accumulation of lipid droplets has been observed in an increasing range of tumors. However, the molecular determinants of this phenotype and the impact of the tumor microenvironment on lipid droplet dynamics are not well defined. The hypoxia-inducible and lipid droplet associated protein HILPDA is known to regulate lipid storage and physiologic responses to feeding conditions in mice, and was recently shown to promote hypoxic lipid droplet formation through inhibition of the rate-limiting lipase adipose triglyceride lipase (ATGL). Here, we identify fatty acid loading and nutrient deprivation–induced autophagy as stimuli of HILPDA-dependent lipid droplet growth. Using mouse embryonic fibroblasts and human tumor cells, we found that genetic ablation of HILPDA compromised hypoxia–fatty acid– and starvation-induced lipid droplet formation and triglyceride storage. Nutrient deprivation upregulated HILPDA protein posttranscriptionally by a mechanism requiring autophagic flux and lipid droplet turnover, independent of HIF1 transactivation. Mechanistically, loss of HILPDA led to elevated lipolysis, which could be corrected by inhibition of ATGL. Lipidomic analysis revealed not only quantitative but also qualitative differences in the glycerolipid and phospholipid profile of HILPDA wild-type and knockout cells, indicating additional HILPDA functions affecting lipid metabolism. Deletion studies of HILPDA mutants identified the N-terminal hydrophobic domain as sufficient for targeting to lipid droplets and restoration of triglyceride storage. In vivo, HILPDA-ablated cells showed decreased intratumoral triglyceride levels and impaired xenograft tumor growth associated with elevated levels of apoptosis.
Implications:
Tumor microenvironmental stresses induce changes in lipid droplet dynamics via HILPDA. Regulation of triglyceride hydrolysis is crucial for cell homeostasis and tumor growth.
Data from Outcome-Related Differences in Gene Expression Profiles of High-Grade Serous Ovarian Cancers Following Neoadjuvant Chemotherapy
Authors: Octeau David , Kessous Roy , Klein Kathleen , Kogan Liron , Pelmus Manuella , Ferenczy Alex , Greenwood Celia M.T. , Van Kempen Leon C. , Salvador Shannon , Lau Susie , Tonin Patricia N. , Yasmeen Amber , Gotlieb Walter H.
Published: March 2024

Abstract
Large-scale genomic studies have detailed the molecular landscape of tumors from patients with high-grade serous ovarian cancers (HGSC) who underwent primary debulking surgery and correlated the identified subgroups to survival. In recent years, there is increased use of neoadjuvant chemotherapy (NACT) for patients with HGSC and while abundant data exist for patients who underwent primary debulking, little data are available on the cancer cells remaining after NACT that could lead to recurrences. We aimed to analyze gene expression profiles of NACT-treated HGSC tumor samples, and correlate them to treatment response and outcome. Tumor samples were collected from patients with stage III or IV HGSC (NACT cohort, N = 57) at the time of surgery and diagnosis (biopsy samples N = 8). Tumor content was validated by histologic examination and bioinformatics. Gene expression analysis was performed using a tailored NanoString-based assay, while sequencing was performed using MiSeq. A cross-validated survival classifier revealed patient clusters with either a “Better” or “Worse” prognostic outcome. The association with overall survival remained significant after controlling for clinical variables, and differential gene expression, gene set enrichment analyses, and the appropriate survival models were used to assess the associations between alterations in gene expression in cancer cells remaining after NACT and outcome. Pathway-based analysis of the differentially expressed genes revealed comparatively high levels of cell cycle and DNA repair gene expression in the poor outcome group.
Implications:
Our work suggests mRNA expression patterns in key genes following NACT may reflect response to treatment and outcome in patient with HGSC.
Data from ALK Fusion Partners Impact Response to ALK Inhibition: Differential Effects on Sensitivity, Cellular Phenotypes, and Biochemical Properties
Authors: Childress Merrida A. , Himmelberg Stephen M. , Chen Huiqin , Deng Wanleng , Davies Michael A. , Lovly Christine M.
Published: March 2024

Abstract
Oncogenic tyrosine kinase fusions involving the anaplastic lymphoma kinase (ALK) are detected in numerous tumor types. Although more than 30 distinct 5′ fusion partner genes have been reported, treatment of ALK-rearranged cancers is decided without regard to which 5′ partner is present. There is little data addressing how the 5′ partner affects the biology of the fusion or responsiveness to ALK tyrosine kinase inhibitors (TKI). On the basis of the hypothesis that the 5′ partner influences the intrinsic properties of the fusion protein, cellular functions that impact oncogenic potential, and sensitivity to ALK TKIs, clonal 3T3 cell lines stably expressing seven different ALK fusion variants were generated. Biochemical and cellular assays were used to assess the efficacy of various ALK TKIs in clinical use, transformative phenotypes, and biochemical properties of each fusion. All seven ALK fusions induced focus formation and colonies in soft agar, albeit to varying degrees. IC50s were calculated for different ALK TKIs (crizotinib, ensartinib, alectinib, lorlatinib) and consistent differences (5–10 fold) in drug sensitivity were noted across the seven ALK fusions tested. Finally, biochemical analyses revealed negative correlations between kinase activity and protein stability. These results demonstrate that the 5′ fusion partner plays an important biological role that affects sensitivity to ALK TKIs.

Implications: This study shows that the 5′ ALK fusion partner influences ALK TKI drug sensitivity. As many other kinase fusions are found in numerous cancers, often with overlapping fusion partners, these studies have ramifications for other kinase-driven malignancies. Mol Cancer Res; 16(11); 1724–36. ©2018 AACR.
Data from A LHFPL3-AS1/miR-580-3p/STAT3 Feedback Loop Promotes the Malignancy in Melanoma via Activation of JAK2/STAT3 Signaling
Authors: Peng Qian , Liu Linbo , Pei Hui , Zhang Jianwen , Chen Minjing , Zhai Xiaomei
Published: March 2024

Abstract
Melanoma is one of the severe skin cancers, accounting for three fourths of all deaths caused by skin cancers and gathering attention from researchers. Previous studies have elucidated that long noncoding RNAs (lncRNA) engage actively in tissue physiology and disease development, especially in tumorigenesis. LncRNA LHFPL3 antisense RNA 1 (LHFPL3-AS1) has rarely been mentioned in researches regarding cancers; therefore, the underlying role and function of LHFPL3-AS1 in melanoma arouse our interest. Data from our work suggested that LHFPL3-AS1 expression was markedly elevated in melanoma tissues and cells. Of note, patients with melanoma with high level of LHFPL3-AS1 were burdened with unfavorable prognosis. Functionally, it has been revealed that LHFPL3-AS1 exerted pro-growth, pro-invasion, and pro-EMT functions in melanoma. Mechanistically, it was figured out that LHFPL3-AS1 could be transcriptionally activated by STAT3. In turn, LHFPL3-AS1 served as a sponge of miR-580-3p to augment STAT3 expression, resulting in activated JAK2/STAT3 signaling pathway in melanoma.
Implications:
Our study revealed a novel positive feedback loop LHFPL3-AS1/miR-580-3p/STAT3 in melanoma, which might contribute to finding potential therapeutic targets for melanoma.
Data from Growth-Inhibitory Activity of Bone Morphogenetic Protein 4 in Human Glioblastoma Cell Lines Is Heterogeneous and Dependent on Reduced SOX2 Expression
Authors: Dalmo Erika , Johansson Patrik , Niklasson Mia , Gustavsson Ida , Nelander Sven , Westermark Bengt
Published: March 2024

Abstract
Glioblastoma multiforme continues to have a dismal prognosis. Even though detailed information on the genetic aberrations in cell signaling and cell-cycle checkpoint control is available, no effective targeted treatment has been developed. Despite the advanced molecular defects, glioblastoma cells may have remnants of normal growth-inhibitory pathways, such as the bone morphogenetic protein (BMP) signaling pathway. We have evaluated the growth-inhibitory effect of BMP4 across a broad spectrum of patient samples, using a panel of 40 human glioblastoma initiating cell (GIC) cultures. A wide range of responsiveness was observed. BMP4 sensitivity was positively correlated with a proneural mRNA expression profile, high SOX2 activity, and BMP4-dependent upregulation of genes associated with inhibition of the MAPK pathway, as demonstrated by gene set enrichment analysis. BMP4 response in sensitive cells was mediated by the canonical BMP receptor pathway involving SMAD1/5/9 phosphorylation and SMAD4 expression. SOX2 was consistently downregulated in BMP4-treated cells. Forced expression of SOX2 attenuated the BMP4 sensitivity including a reduced upregulation of MAPK-inhibitory genes, implying a functional relationship between SOX2 downregulation and sensitivity. The results show an extensive heterogeneity in BMP4 responsiveness among GICs and identify a BMP4-sensitive subgroup, in which SOX2 is a mediator of the response.
Implications:
Development of agonists targeting the BMP signaling pathway in glioblastoma is an attractive avenue toward a better treatment. Our study may help find biomarkers that predict the outcome of such treatment and enable stratification of patients.
Data from Kinetics of Nuclear Uptake and Site-Specific DNA Cleavage during CRISPR-Directed Gene Editing in Solid Tumor Cells
Authors: Banas Kelly , Rivera-Torres Natalia , Bialk Pawel , Yoo Byung-Chun , Kmiec Eric B.
Published: March 2024

Abstract
Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)–directed gene editing is approaching clinical implementation in cancer. Thus, it is imperative to define the molecular framework upon which safe and efficacious therapeutic strategies can be built. Two important reaction parameters include the biological time frame within which the CRISPR/Cas complex enters the nucleus and executes gene editing, and the method of discrimination that the CRISPR/Cas complex utilizes to target tumor cell, but not normal cell, genomes. We are developing CRISPR-directed gene editing for the treatment of non–small cell lung carcinoma focusing on disabling Nuclear Factor Erythroid 2-Related Factor-Like (NRF2), a transcription factor that regulates chemoresistance and whose genetic disruption would enhance chemosensitivity. In this report, we define the time frame of cellular events that surround the initialization of CRISPR-directed gene editing as a function of the nuclear penetration and the execution of NRF2 gene disruption. We also identify a unique protospacer adjacent motif that facilitates site-specific cleavage of the NRF2 gene present only in tumor genomes.
Implications:
Our results begin to set a scientifically meritorious foundation for the exploitation of CRISPR-directed gene editing as an augmentative therapy for lung cancer and other solid tumors.
Visual Overview:
http://mcr.aacrjournals.org/content/molcanres/18/6/891/F1.large.jpg.
Data from HSF1-Mediated Control of Cellular Energy Metabolism and mTORC1 Activation Drive Acute T-Cell Lymphoblastic Leukemia Progression
Authors: Eroglu Binnur , Pang Junfeng , Jin Xiongjie , Xi Caixia , Moskophidis Demetrius , Mivechi Nahid F.
Published: March 2024

Abstract
Deregulated oncogenic signaling linked to PI3K/AKT and mTORC1 pathway activation is a hallmark of human T-cell acute leukemia (T-ALL) pathogenesis and contributes to leukemic cell resistance and adverse prognosis. Notably, although the multiagent chemotherapy of leukemia leads to a high rate of complete remission, options for salvage therapy for relapsed/refractory disease are limited due to the serious side effects of augmenting cytotoxic chemotherapy. We report that ablation of HSF1, a key transcriptional regulator of the chaperone response and cellular bioenergetics, from mouse T-ALL tumors driven by PTEN loss or human T-ALL cell lines, has significant therapeutic effects in reducing tumor burden and sensitizing malignant cell death. From a mechanistic perspective, the enhanced sensitivity of T-ALLs to HSF1 depletion resides in the reduced MAPK–ERK signaling and metabolic and ATP-producing capacity of malignant cells lacking HSF1 activity. Impaired mitochondrial ATP production and decreased intracellular amino acid content in HSF1-deficient T-ALL cells trigger an energy-saving adaptive response featured by attenuation of the mTORC1 activity, which is coregulated by ATP, and its downstream target proteins (p70S6K and 4E-BP). This leads to protein translation attenuation that diminishes oncogenic signals and malignant cell growth. Collectively, these metabolic alterations in the absence of HSF1 activity reveal cancer cell liabilities and have a profound negative impact on T-ALL progression.
Implications:
Targeting HSF1 and HSF1-dependent cancer-specific anabolic and protein homeostasis programs has a significant therapeutic potential for T-ALL and may prevent progression of relapsed/refractory disease.
Data from Augmented HR Repair Mediates Acquired Temozolomide Resistance in Glioblastoma
Authors: Gil del Alcazar Carlos Rodrigo , Todorova Pavlina Krasimirova , Habib Amyn A. , Mukherjee Bipasha , Burma Sandeep
Published: March 2024

Abstract
Glioblastoma (GBM) is the most common and aggressive primary brain tumor in adults and is universally fatal. The DNA alkylating agent temozolomide is part of the standard-of-care for GBM. However, these tumors eventually develop therapy-driven resistance and inevitably recur. While loss of mismatch repair (MMR) and re-expression of MGMT have been shown to underlie chemoresistance in a fraction of GBMs, resistance mechanisms operating in the remaining GBMs are not well understood. To better understand the molecular basis for therapy-driven temozolomide resistance, mice bearing orthotopic GBM xenografts were subjected to protracted temozolomide treatment, and cell lines were generated from the primary (untreated) and recurrent (temozolomide-treated) tumors. As expected, the cells derived from primary tumors were sensitive to temozolomide, whereas the cells from the recurrent tumors were significantly resistant to the drug. Importantly, the acquired resistance to temozolomide in the recurrent lines was not driven by re-expression of MGMT or loss of MMR but was due to accelerated repair of temozolomide-induced DNA double-strand breaks (DSB). Temozolomide induces DNA replication–associated DSBs that are primarily repaired by the homologous recombination (HR) pathway. Augmented HR appears to underpin temozolomide resistance in the recurrent lines, as these cells were cross-resistant to other agents that induced replication-associated DSBs, exhibited faster resolution of damage-induced Rad51 foci, and displayed higher levels of sister chromatid exchanges (SCE). Furthermore, in light of recent studies demonstrating that CDK1 and CDK2 promote HR, it was found that CDK1/2 inhibitors countered the heightened HR in recurrent tumors and sensitized these therapy-resistant tumor cells to temozolomide.

Implications: Augmented HR repair is a novel mechanism underlying acquired temozolomide resistance in GBM, and this raises the possibility of improving the therapeutic response to temozolomide by targeting HR with small-molecule inhibitors of CDK1/2. Mol Cancer Res; 14(10); 928–40. ©2016 AACR.
Data from A Protein Interaction between β-Catenin and Dnmt1 Regulates Wnt Signaling and DNA Methylation in Colorectal Cancer Cells
Authors: Song Jing , Du Zhanwen , Ravasz Mate , Dong Bohan , Wang Zhenghe , Ewing Rob M.
Published: March 2024

Abstract
Aberrant activation of the Wnt signaling pathway is an important step in the initiation and progression of tumor development in diverse cancers. The central effector of canonical Wnt signaling, β-catenin (CTNNB1), is a multifunctional protein, and has been extensively studied with respect to its roles in cell–cell adhesion and in regulation of Wnt-driven transcription. Here, a novel mass spectrometry–based proteomics technique in colorectal cancer cells expressing stabilized β-catenin, was used to identify a protein–protein interaction between β-catenin and DNA methyltransferase I (Dnmt1) protein, the primary regulator of DNA methylation patterns in mammalian cells. Dnmt1 and β-catenin strongly colocalized in the nuclei of colorectal cancer cells, and the interaction is mediated by the central domain of the Dnmt1 protein. Dnmt1 protein abundance is dependent upon the levels of β-catenin, and is increased in cells expressing stabilized mutant β-catenin. Conversely, the Dnmt1 regulates the levels of nuclear β-catenin and β-catenin/TCF–driven transcription. In addition, lysine-specific demethylase 1 (LSD1/KDM1A), a regulator of DNMT1 stability, was identified as a component of the Dnmt1–β-catenin protein complex and perturbation of the Dnmt1–β-catenin interaction altered DNA methylation. In summary, a functional protein–protein interaction was identified between two critically important oncoproteins, in turn revealing a link between Wnt signaling and downstream nuclear functions mediated by Dnmt1.

Implications: Two critical oncoproteins, Dnmt1 and β-catenin, mutually regulate one each other's levels and activities in colorectal cancer cells. Mol Cancer Res; 13(6); 969–81. ©2015 AACR.
Data from Telomere DNA Damage Signaling Regulates Prostate Cancer Tumorigenesis
Authors: Wu Jianchun , Crowe David L.
Published: March 2024

Abstract
Telomere shortening has been demonstrated in benign prostatic hypertrophy (BPH), which is associated with prostate epithelial cell senescence. Telomere shortening is the most frequently observed genetic alteration in prostatic intraepithelial neoplasia, and is associated with poor clinical outcomes in prostate cancer. Gene expression database analysis revealed decreased TRF2 expression during malignant progression of the prostate gland. We reasoned that reduced TRF2 expression in prostate epithelium, by activating the telomere DNA damage response, would allow us to model both benign and malignant prostate disease. Prostate glands with reduced epithelial TRF2 expression developed age- and p53-dependent hypertrophy, senescence, ductal dilation, and smooth muscle hyperplasia similar to human BPH. Prostate tumors with reduced TRF2 expression were classified as high-grade androgen receptor–negative adenocarcinomas, which exhibited decreased latency, increased proliferation, and distant metastases. Prostate cancer stem cells with reduced TRF2 expression were highly tumorigenic and maintained telomeres both by telomerase and alternative lengthening (ALT). Telomerase inhibition in prostate glands with reduced TRF2 expression produced significant reduction in prostate tumor incidence by halting progression at intraepithelial neoplasia (PIN). These lesions were highly differentiated, exhibited low proliferation index, and high apoptotic cell fraction. Prostate tumors with reduced TRF2 expression and telomerase inhibition failed to metastasize and did not exhibit ALT.
Implications:
Our results demonstrate that the telomere DNA damage response regulates BPH, PIN, and prostate cancer and may be therapeutically manipulated to prevent prostate cancer progression.
Data from Hypoxia Provokes Base Excision Repair Changes and a Repair-Deficient, Mutator Phenotype in Colorectal Cancer Cells
Authors: Chan Norman , Ali Mohsin , McCallum Gordon P. , Kumareswaran Ramya , Koritzinsky Marianne , Wouters Bradly G. , Wells Peter G. , Gallinger Steven , Bristow Robert G.
Published: March 2024

Abstract
Regions of acute and chronic hypoxia exist within solid tumors and can lead to increased rates of mutagenesis and/or altered DNA damage and repair protein expression. Base excision repair (BER) is responsible for resolving small, non–helix-distorting lesions from the genome that potentially cause mutations by mispairing or promoting DNA breaks during replication. Germline and somatic mutations in BER genes, such as MutY Homolog (MUTYH/MYH) and DNA-directed polymerase (POLB), are associated with increased risk of colorectal cancer. However, very little is known about the expression and function of BER proteins under hypoxic stress. Using conditions of chronic hypoxia, decreased expression of BER proteins was observed because of a mechanism involving suppressed BER protein synthesis in multiple colorectal cancer cell lines. Functional BER was impaired as determined by MYH- and 8-oxoguanine (OGG1)–specific glycosylase assays. A formamidopyrimidine-DNA glycosylase (Fpg) Comet assay revealed elevated residual DNA base damage in hypoxic cells 24 hours after H2O2 treatment as compared with normoxic controls. Similarly, high-performance liquid chromatography analysis demonstrated that 8-oxo-2′-deoxyguanosine lesions were elevated in hypoxic cells 3 and 24 hours after potassium bromate (KBrO3) treatment when compared with aerobic cells. Correspondingly, decreased clonogenic survival was observed following exposure to the DNA base damaging agents H2O2 and MMS, but not to the microtubule interfering agent paclitaxel. Thus, a persistent downregulation of BER components by the microenvironment modifies and facilitates a mutator phenotype, driving genetic instability and cancer progression.

Implications: Aberrant BER is a contributing factor for the observed genetic instability in hypoxic tumor cells. Mol Cancer Res; 12(10); 1407–15. ©2014 AACR.
Data from SIX1 Oncoprotein as a Biomarker in a Model of Hormonal Carcinogenesis and in Human Endometrial Cancer
Authors: Suen Alisa A. , Jefferson Wendy N. , Wood Charles E. , Padilla-Banks Elizabeth , Bae-Jump Victoria L. , Williams Carmen J.
Published: March 2024

Abstract
The oncofetal protein sine oculis-related homeobox 1 (SIX1) is a developmental transcription factor associated with carcinogenesis in several human cancer types but has not been investigated in human endometrial cancer. In a model of hormonal carcinogenesis, mice neonatally exposed to the soy phytoestrogen genistein (GEN) or the synthetic estrogen diethylstilbestrol (DES) develop endometrial cancer as adults. Previously, we demonstrated that SIX1 becomes aberrantly expressed in the uteri of these mice. Here, we used this mouse model to investigate the role of SIX1 expression in endometrial carcinoma development and used human tissue microarrays to explore the utility of SIX1 as a biomarker in human endometrial cancer. In mice neonatally exposed to GEN or DES, the Six1 transcript level increased dramatically over time in uteri at 6, 12, and 18 months of age and was associated with development of endometrial carcinoma. SIX1 protein localized within abnormal basal cells and all atypical hyperplastic and neoplastic lesions. These findings indicate that developmental estrogenic chemical exposure induces persistent endometrial SIX1 expression that is strongly associated with abnormal cell differentiation and cancer development. In human endometrial tissue specimens, SIX1 was not present in normal endometrium but was expressed in a subset of endometrial cancers in patients who were also more likely to have late-stage disease. These findings identify SIX1 as a disease biomarker in a model of hormonal carcinogenesis and suggest that SIX1 plays a role in endometrial cancer development in both mice and women.

Implications: The SIX1 oncoprotein is aberrantly expressed in the endometrium following developmental exposure to estrogenic chemicals, correlates with uterine cancer, and is a biomarker in human endometrial cancers. Mol Cancer Res; 14(9); 849–58. ©2016 AACR.
Data from Targeting NAD+ Biosynthesis Overcomes Panobinostat and Bortezomib-Induced Malignant Glioma Resistance
Authors: Jane Esther P. , Premkumar Daniel R. , Thambireddy Swetha , Golbourn Brian , Agnihotri Sameer , Bertrand Kelsey C. , Mack Stephen C. , Myers Max I. , Chattopadhyay Ansuman , Taylor D. Lansing , Schurdak Mark E. , Stern Andrew M. , Pollack Ian F.
Published: March 2024

Abstract
To improve therapeutic responses in patients with glioma, new combination therapies that exploit a mechanistic understanding of the inevitable emergence of drug resistance are needed. Intratumoral heterogeneity enables a low barrier to resistance in individual patients with glioma. We reasoned that targeting two or more fundamental processes that gliomas are particularly dependent upon could result in pleiotropic effects that would reduce the diversity of resistant subpopulations allowing convergence to a more robust therapeutic strategy. In contrast to the cytostatic responses observed with each drug alone, the combination of the histone deacetylase inhibitor panobinostat and the proteasome inhibitor bortezomib synergistically induced apoptosis of adult and pediatric glioma cell lines at clinically achievable doses. Resistance that developed was examined using RNA-sequencing and pharmacologic screening of resistant versus drug-naïve cells. Quinolinic acid phosphoribosyltransferase (QPRT), the rate-determining enzyme for de novo synthesis of NAD+ from tryptophan, exhibited particularly high differential gene expression in resistant U87 cells and protein expression in all resistant lines tested. Reducing QPRT expression reversed resistance, suggesting that QPRT is a selective and targetable dependency for the panobinostat–bortezomib resistance phenotype. Pharmacologic inhibition of either NAD+ biosynthesis or processes such as DNA repair that consume NAD+ or their simultaneous inhibition with drug combinations, specifically enhanced apoptosis in treatment-resistant cells. Concomitantly, de novo vulnerabilities to known drugs were observed.
Implications:
These data provide new insights into mechanisms of treatment resistance in gliomas, hold promise for targeting recurrent disease, and provide a potential strategy for further exploration of next-generation inhibitors.
Data from ZBTB7A Suppresses Melanoma Metastasis by Transcriptionally Repressing MCAM
Authors: Liu Xue-Song , Genet Matthew D. , Haines Jenna E. , Mehanna Elie K. , Wu Shaowei , Chen Hung-I Harry , Chen Yidong , Qureshi Abrar A. , Han Jiali , Chen Xiang , Fisher David E. , Pandolfi Pier Paolo , Yuan Zhi-Min
Published: March 2024

Abstract
The excessive metastatic propensity of melanoma makes it the most deadly form of skin cancer, yet the underlying mechanism of metastasis remains elusive. Here, mining of cancer genome datasets discovered a frequent loss of chromosome 19p13.3 and associated downregulation of the zinc finger transcription factor ZBTB7A in metastatic melanoma. Functional assessment of ZBTB7A-regulated genes identified MCAM, which encodes an adhesion protein key to melanoma metastasis. Using an integrated approach, it is demonstrated that ZBTB7A directly binds to the promoter and transcriptionally represses the expression of MCAM, establishing ZBTB7A as a bona fide transcriptional repressor of MCAM. Consistently, downregulation of ZBTB7A results in marked upregulation of MCAM and enhanced melanoma cell invasion and metastasis. An inverse correlation of ZBTB7A and MCAM expression in association with melanoma metastasis is further validated with data from analysis of human melanoma specimens.

Implications: Together, these results uncover a previously unrecognized role of ZBTB7A in negative regulation of melanoma metastasis and have important clinical implications. Mol Cancer Res; 13(8); 1206–17. ©2015 AACR.
Data from The YAP-Interacting Phosphatase SHP2 Can Regulate Transcriptional Coactivity and Modulate Sensitivity to Chemotherapy in Cholangiocarcinoma
Authors: Buckarma EeeLN H. , Werneburg Nathan W. , Conboy Caitlin B. , Kabashima Ayano , O'Brien Daniel R. , Wang Chen , Ilyas Sumera I. , Smoot Rory L.
Published: March 2024

Abstract
The Hippo pathway effector Yes-associated protein (YAP) is localized to the nucleus and transcriptionally active in a number of tumor types, including a majority of human cholangiocarcinomas. YAP activity has been linked to chemotherapy resistance and has been shown to rescue KRAS and BRAF inhibition in RAS/RAF-driven cancers; however, the underlying mechanisms of YAP-mediated chemoresistance have yet to be elucidated. Herein, we report that the tyrosine phosphatase SHP2 directly regulates the activity of YAP by dephosphorylating pYAPY357 even in the setting of RAS/RAF mutations, and that diminished SHP2 phosphatase activity is associated with chemoresistance in cholangiocarcinomas. A screen for YAP-interacting tyrosine phosphatases identified SHP2, and characterization of cholangiocarcinomas cell lines demonstrated an inverse relationship between SHP2 levels and pYAPY357. Human sequencing data demonstrated lower SHP2 levels in cholangiocarcinomas tumors as compared with normal liver. Cell lines with low SHP2 expression and higher levels of pYAPY357 were resistant to gemcitabine and cisplatin. In cholangiocarcinomas cells with high levels of SHP2, pharmacologic inhibition or genetic deletion of SHP2 increased YAPY357 phosphorylation and expression of YAP target genes, including the antiapoptotic regulator MCL1, imparting resistance to gemcitabine and cisplatin. In vivo evaluation of chemotherapy sensitivity demonstrated significant resistance in xenografts with genetic deletion of SHP2, which could be overcome by utilizing an MCL1 inhibitor.
Implications:
These findings demonstrate a role for SHP2 in regulating YAP activity and chemosensitivity, and suggest that decreased phosphatase activity may be a mechanism of chemoresistance in cholangiocarcinoma via a MCL1-mediated mechanism.
Data from Cholesterol Sulfonation Enzyme, SULT2B1b, Modulates AR and Cell Growth Properties in Prostate Cancer
Authors: Vickman Renee E. , Crist Scott A. , Kerian Kevin , Eberlin Livia , Cooks R. Graham , Burcham Grant N. , Buhman Kimberly K. , Hu Chang-Deng , Mesecar Andrew D. , Cheng Liang , Ratliff Timothy L.
Published: March 2024

Abstract
Cholesterol accumulates in prostate lesions and has been linked to prostate cancer incidence and progression. However, how accumulated cholesterol contributes to prostate cancer development and progression is not completely understood. Cholesterol sulfate (CS), the primary sulfonation product of cholesterol sulfotransferase (SULT2B1b), accumulates in human prostate adenocarcinoma and precancerous prostatic intraepithelial neoplasia (PIN) lesions compared with normal regions of the same tissue sample. Given the enhanced accumulation of CS in these lesions, it was hypothesized that SULT2B1b-mediated production of CS provides a growth advantage to these cells. To address this, prostate cancer cells with RNAi-mediated knockdown (KD) of SULT2B1b were used to assess the impact on cell growth and survival. SULT2B1b is expressed and functional in a variety of prostate cells, and the data demonstrate that SULT2B1b KD, in LNCaP and other androgen-responsive (VCaP and C4-2) cells, results in decreased cell growth/viability and induces cell death. SULT2B1b KD also decreases androgen receptor (AR) activity and expression at mRNA and protein levels. While AR overexpression has no impact on SULT2B1b KD-mediated cell death, the addition of exogenous androgen is able to partially rescue the growth inhibition induced by SULT2B1b KD in LNCaP cells. These results suggest that SULT2B1b positively regulates the AR either through alterations in ligand availability or by interaction with critical coregulators that influence AR activity.

Implications: These findings provide evidence that SULT2B1b is a novel regulator of AR activity and cell growth in prostate cancer and should be further investigated for therapeutic potential. Mol Cancer Res; 14(9); 776–86. ©2016 AACR.
Data from Iron Regulatory Protein 2 Exerts its Oncogenic Activities by Suppressing TAp63 Expression
Authors: Zhang Yanhong , Feng Xiuli , Zhang Jin , Chen Xinbin
Published: March 2024

Abstract
Iron regulatory protein 2 (IRP2) is a key regulator of iron homeostasis and is found to be altered in several types of human cancer. However, how IRP2 contributes to tumorigenesis remains to be elucidated. In this study, we sought to investigate the role of IRP2 in tumorigenesis and found that IRP2 promotes cell growth by repressing TAp63, a member of p53 tumor suppressor family. Specifically, we found that IRP2 overexpression decreased, whereas IRP2 deficiency increased, TAp63 expression. We also showed that the repression of TAp63 by IRP2 was independent of tumor suppressor p53. To uncover the molecular basis, we found that IRP2 stabilized TAp63 mRNA by binding to an iron response element in the 3′UTR of p63 mRNA. To determine the biological significance of this regulation, we showed that IRP2 facilitates cell proliferation, at least in part, via repressing TAp63 expression. Moreover, we found that IRP2 deficiency markedly alleviated cellular senescence in TAp63-deficient mouse embryo fibroblasts. Together, we have uncovered a novel regulation of TAp63 by IRP2 and our data suggest that IRP2 exerts its oncogenic activities at least in part by repressing TAp63 expression.
Implications:
We have revealed a novel regulation of TAp63 by IRP2 and our data suggest that IRP2 exerts its oncogenic activities, at least in part, by repressing TAp63 expression.
Data from Targeting TSLP-Induced Tyrosine Kinase Signaling Pathways in CRLF2-Rearranged Ph-like ALL
Authors: Sia Keith C.S. , Zhong Ling , Mayoh Chelsea , Norris Murray D. , Haber Michelle , Marshall Glenn M. , Raftery Mark J. , Lock Richard B.
Published: March 2024

Abstract
Philadelphia (Ph)-like acute lymphoblastic leukemia (ALL) is characterized by aberrant activation of signaling pathways and high risk of relapse. Approximately 50% of Ph-like ALL cases overexpress cytokine receptor-like factor 2 (CRLF2) associated with gene rearrangement. Activated by its ligand thymic stromal lymphopoietin (TSLP), CRLF2 signaling is critical for the development, proliferation, and survival of normal lymphocytes. To examine activation of tyrosine kinases regulated by TSLP/CRLF2, phosphotyrosine (P-Tyr) profiling coupled with stable isotope labeling of amino acids in cell culture (SILAC) was conducted using two CRLF2-rearranged (CRLF2r) Ph-like ALL cell lines stimulated with TSLP. As a result, increased P-Tyr was detected in previously reported TSLP-activated tyrosine kinases and substrates, including JAK1, JAK2, STAT5, and ERK1/2. Interestingly, TSLP also increased P-Tyr of insulin growth factor 1 receptor (IGF1R) and fibroblast growth factor receptor 1 (FGFR1), both of which can be targeted with small-molecule inhibitors. Fixed-ratio combination cytotoxicity assays using the tyrosine kinase inhibitors BMS-754807 and ponatinib that target IGF1R and FGFR1, respectively, revealed strong synergy against both cell line and patient-derived xenograft (PDX) models of CRLF2r Ph-like ALL. Further analyses also indicated off-target effects of ponatinib in the synergy, and novel association of the Ras-associated protein-1 (Rap1) signaling pathway with TSLP signaling in CRLF2r Ph-like ALL. When tested in vivo, the BMS-754807/ponatinib combination exerted minimal efficacy against 2 Ph-like ALL PDXs, associated with low achievable plasma drug concentrations. Although this study identified potential new targets in CRLF2r Ph-like ALL, it also highlights that in vivo validation of synergistic drug interactions is essential.
Implication:
Quantitative phosphotyrosine profiling identified potential therapeutic targets for high-risk CRLF2-rearranged Ph-like ALL.
Data from Integrative Genomic Analyses Yield Cell-Cycle Regulatory Programs with Prognostic Value
Authors: Cheng Chao , Lou Shaoke , Andrews Erik H. , Ung Matthew H. , Varn Frederick S.
Published: March 2024

Abstract
Liposarcoma is the second most common form of sarcoma, which has been categorized into four molecular subtypes, which are associated with differential prognosis of patients. However, the transcriptional regulatory programs associated with distinct histologic and molecular subtypes of liposarcoma have not been investigated. This study uses integrative analyses to systematically define the transcriptional regulatory programs associated with liposarcoma. Likewise, computational methods are used to identify regulatory programs associated with different liposarcoma subtypes, as well as programs that are predictive of prognosis. Further analysis of curated gene sets was used to identify prognostic gene signatures. The integration of data from a variety of sources, including gene expression profiles, transcription factor–binding data from ChIP-Seq experiments, curated gene sets, and clinical information of patients, indicated discrete regulatory programs (e.g., controlled by E2F1 and E2F4), with significantly different regulatory activity in one or multiple subtypes of liposarcoma with respect to normal adipose tissue. These programs were also shown to be prognostic, wherein liposarcoma patients with higher E2F4 or E2F1 activity associated with unfavorable prognosis. A total of 259 gene sets were significantly associated with patient survival in liposarcoma, among which >50% are involved in cell cycle and proliferation.

Implications: These integrative analyses provide a general framework that can be applied to investigate the mechanism and predict prognosis of different cancer types. Mol Cancer Res; 14(4); 332–43. ©2016 AACR.
Data from Interplay Between V-ATPase G1 and Small EV-miRNAs Modulates ERK1/2 Activation in GBM Stem Cells and Nonneoplastic Milieu
Authors: Bertolini Irene , Storaci Alessandra Maria , Terrasi Andrea , Cristofori Andrea Di , Locatelli Marco , Caroli Manuela , Ferrero Stefano , Altieri Dario C. , Vaira Valentina
Published: March 2024

Abstract
The ATP6V1G1 subunit (V1G1) of the vacuolar proton ATPase (V-ATPase) pump is crucial for glioma stem cells (GSC) maintenance and in vivo tumorigenicity. Moreover, V-ATPase reprograms the tumor microenvironment through acidification and release of extracellular vesicles (EV). Therefore, we investigated the role of V1G1 in GSC small EVs and their effects on primary brain cultures. To this end, small EVs were isolated from patients-derived GSCs grown as neurospheres (NS) with high (V1G1HIGH-NS) or low (V1G1LOW-NS) V1G1 expression and analyzed for V-ATPase subunits presence, miRNA contents, and cellular responses in recipient cultures. Our results show that NS-derived small EVs stimulate proliferation and motility of recipient cells, with small EV derived from V1G1HIGH-NS showing the most pronounced activity. This involved activation of ERK1/2 signaling, in a response reversed by V-ATPase inhibition in NS-producing small EV. The miRNA profile of V1G1HIGH-NS–derived small EVs differed significantly from that of V1G1LOW-NS, which included miRNAs predicted to target MAPK/ERK signaling. Mechanistically, forced expression of a MAPK-targeting pool of miRNAs in recipient cells suppressed MAPK/ERK pathway activation and blunted the prooncogenic effects of V1G1HIGH small EV. These findings propose that the GSC influences the brain milieu through a V1G1-coordinated EVs release of MAPK/ERK-targeting miRNAs. Interfering with V-ATPase activity could prevent ERK-dependent oncogenic reprogramming of the microenvironment, potentially hampering local GBM infiltration.
Implications:
Our data identify a novel molecular mechanism of gliomagenesis specific of the GBM stem cell niche, which coordinates a V-ATPase–dependent reprogramming of the brain microenvironment through the release of specialized EVs.
Data from Galectin-3 Interacts with C/EBPβ and Upregulates Hyaluronan-Mediated Motility Receptor Expression in Gastric Cancer
Authors: Kang Hyeon-Gu , Kim Won-Jin , Kang Hyeok-Gu , Chun Kyung-Hee , Kim Seok-Jun
Published: March 2024

Abstract
The hyaluronan-mediated motility receptor (HMMR) is overexpressed in gastric cancer; however, the apparent role of HMMR has not been well defined owing to lack of detailed studies on gastric tumorigenesis. Therefore, we elucidated the functional and regulatory mechanisms of HMMR in gastric cancer. Using publicly available data, we confirmed HMMR overexpression in patients with gastric cancer. HMMR silencing decreased proliferation, migration, and invasion of gastric cancer cells, whereas HMMR overexpression reversed these effects. A gastric cancer xenograft mouse model showed statistically significant inhibition of tumor growth upon HMMR depletion. Previous data from cDNA microarray showed reduced HMMR expression upon inhibition of galectin-3. However, overexpression of galectin-3 increased HMMR expression, cell proliferation, and motility in gastric cancer cells, whereas HMMR silencing blocked these effects. Interestingly, galectin-3 interacted directly with C/EBPβ and bound to HMMR promoter to drive its transcription, and gastric cancer cell proliferation and motility. Altogether, high expression of HMMR promoted gastric cancer cell proliferation and motility and could be a prognostic factor in gastric cancer. In addition, HMMR expression was regulated by the interaction between C/EBPβ and galectin-3. Therefore, targeting HMMR along with galectin-3 and C/EBPβ complex could be a potential treatment strategy for inhibiting gastric cancer progression and metastasis.
Implications:
This study provides evidence that galectin-3 interacts with C/EBPβ in gastric cancer, and galectin-3 and C/EBPβ complex promotes gastric cancer cell progression and motility through upregulating HMMR expression.