bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from MET and ERBB2 Are Coexpressed in ERBB2+ Breast Cancer and Contribute to Innate Resistance
Authors: Paulson Amanda K. , Linklater Erik S. , Berghuis Bree D. , App Colleen A. , Oostendorp Leon D. , Paulson Jayne E. , Pettinga Jane E. , Melnik Marianne K. , Vande Woude George F. , Graveel Carrie R.
Published: April 2023

Abstract
Breast cancer displays significant intratumoral heterogeneity, which has been shown to have a substantial impact on both innate and acquired resistance to tyrosine kinase inhibitors. The heterogeneous expression of multiple receptor tyrosine kinases (RTK) in cancers supports tumor signaling robustness and plays a significant role in resistance to targeted inhibition. Recent studies have revealed interactions between the MET receptor and the ERBB receptor family in the therapeutic resistance of several cancers. In this study, the relationship between MET expression/activity and the expression/activity of the ERBB receptor family in human breast cancer was interrogated. Importantly, a significant percentage of ERBB2+ tumors coexpressing MET and ERBB2 were observed and displayed significant heterogeneity with subpopulations of cells that are MET−/ERBB2+, MET+/ERBB2−, and MET+/ERBB2+. In a MET+/ERBB2+ breast cancer cell line, MET depletion resulted in increased ERBB2 activation, and conversely, ERBB2 depletion resulted in increased MET activation. Neither EGFR nor ERBB3 compensated for MET or ERBB2 knockdown. The loss of either MET or ERBB2 led to a decrease in PI3K/AKT signaling and increased dependency on MAPK. These data show that a subset of ERBB2+ breast cancers express MET and contain MET+/ERBB2+ subpopulations. Moreover, analysis of RTK activation during ERBB2 knockdown indicated that MET signaling is a compensatory pathway of resistance.

Implications: ERBB2+ breast cancers with MET+/ERBB2+ subpopulations may have an innate resistance to ERBB2 inhibition and may benefit from combined MET and ERBB2 inhibition. Mol Cancer Res; 11(9); 1112–21. ©2013 AACR.
Data from EGFR Inhibition Induces Proinflammatory Cytokines via NOX4 in HNSCC
Authors: Fletcher Elise V.M. , Love-Homan Laurie , Sobhakumari Arya , Feddersen Charlotte R. , Koch Adam T. , Goel Apollina , Simons Andrean L.
Published: April 2023

Abstract
Chronic inflammation plays a fundamental role in tumor promotion, migration, and invasion. With the use of microarray profiling, a profound increase was observed for those transcripts involved in proinflammatory signaling in epidermal growth factor receptor (EGFR) inhibitor–treated head and neck squamous cell carcinoma (HNSCC) cells as compared with their respective controls. As such, it was hypothesized that EGFR inhibitor efficacy is offset by the proinflammatory response that these therapeutics conjure in HNSCC. Systematic evaluation of the clinical EGFR inhibitors—erlotinib, cetuximab, lapatinib, and panitumumab—revealed increased secretion of proinflammatory cytokines such as interleukins (IL-2, IL-4, IL-6, IL-8), granulocyte-macrophage colony-stimulating factor, TNF-α, and IFN-γ. Mechanistic focus on IL-6 revealed that erlotinib induced a time-dependent increase in IL-6 mRNA and protein expression. Importantly, exogenous IL-6 protected HNSCC cells from erlotinib-induced cytotoxicity, whereas tocilizumab, an IL-6 receptor antagonist, sensitized cells to erlotinib in vitro and in vivo. Inhibitors of NF-κB, p38, and JNK suppressed erlotinib-induced IL-6 expression, suggesting critical roles for NF-κB and MAPK in IL-6 regulation. Furthermore, knockdown of NADPH oxidase 4 (NOX4) suppressed erlotinib-induced proinflammatory cytokine expression. Taken together, these results demonstrate that clinical EGFR inhibitors induce the expression of proinflammatory cytokines via NOX4.

Implications: The antitumor activity of EGFR inhibitors is reduced by activation of NOX4-mediated proinflammatory pathways in HNSCC. Mol Cancer Res; 11(12); 1574–84. ©2013 AACR.
Data from PGE2-Driven Expression of c-Myc and OncomiR-17-92 Contributes to Apoptosis Resistance in NSCLC
Authors: Krysan Kostyantyn , Kusko Rebecca , Grogan Tristan , O'Hearn James , Reckamp Karen L. , Walser Tonya C. , Garon Edward B. , Lenburg Marc E. , Sharma Sherven , Spira Avrum E. , Elashoff David , Dubinett Steven M.
Published: April 2023

Abstract
Aberrant expression of microRNAs (miRNA) with oncogenic capacities (oncomiRs) has been described for several different malignancies. The first identified oncomiR, miR-17-92, is frequently overexpressed in a variety of cancers and its targets include the tumor suppressor PTEN. The transcription factor c-Myc (MYC) plays a central role in proliferative control and is rapidly upregulated upon mitogenic stimulation. Expression of c-Myc is frequently deregulated in tumors, facilitating proliferation and inhibiting terminal differentiation. The c-Myc–regulated network comprises a large number of transcripts, including those encoding miRNAs. Here, prostaglandin E2 (PGE2) exposure rapidly upregulates the expression of the MYC gene followed by the elevation of miR-17-92 levels, which in turn suppresses PTEN expression, thus enhancing apoptosis resistance in non–small cell lung cancer (NSCLC) cells. Knockdown of MYC expression or the miR-17-92 cluster effectively reverses this outcome. Similarly, miR-17-92 levels are significantly elevated in NSCLC cells ectopically expressing COX-2. Importantly, circulating miR-17-92 was elevated in the blood of patients with lung cancer as compared with subjects at risk for developing lung cancer. Furthermore, in patients treated with celecoxib, miR-17-92 levels were significantly reduced. These data demonstrate that PGE2, abundantly produced by NSCLC and inflammatory cells in the tumor microenvironment, is able to stimulate cell proliferation and promote resistance to pharmacologically induced apoptosis in a c-Myc and miR-17-92–dependent manner.

Implications: This study describes a novel mechanism, involving c-Myc and miR-17-92, which integrates cell proliferation and apoptosis resistance. Mol Cancer Res; 12(5); 765–74. ©2014 AACR.
Data from Mastermind-Like 3 Controls Proliferation and Differentiation in Neuroblastoma
Authors: Heynen Guus J.J.E. , Nevedomskaya Ekaterina , Palit Sander , Jagalur Basheer Noorjahan , Lieftink Cor , Schlicker Andreas , Zwart Wilbert , Bernards Rene , Bajpe Prashanth Kumar
Published: April 2023

Abstract
Neuroblastoma cell lines can differentiate upon treatment with retinoic acid (RA), a finding that provided the basis for the clinical use of RA to treat neuroblastoma. However, resistance to RA is often observed, which limits its clinical utility. Using a gain-of-function genetic screen, we identified an unexpected link between RA signaling and mastermind-like 3 (MAML3), a known transcriptional coactivator for NOTCH. Our findings indicate that MAML3 expression leads to the loss of activation of a subset of RA target genes, which hampers RA-induced differentiation and promotes resistance to RA. The regulatory DNA elements of this subset of RA target genes show overlap in binding of MAML3 and the RA receptor, suggesting a direct role for MAML3 in the regulation of these genes. In addition, MAML3 has RA-independent functions, including the activation of IGF1R and downstream AKT signaling via upregulation of IGF2, resulting in increased proliferation. These results demonstrate an important mechanistic role for MAML3 in proliferation and RA-mediated differentiation.

Implications: MAML3 coordinates transcription regulation with receptor tyrosine kinase pathway activation, shedding new light on why this gene is mutated in multiple cancers. Mol Cancer Res; 14(5); 411–22. ©2016 AACR.
Data from CAF-Secreted Annexin A1 Induces Prostate Cancer Cells to Gain Stem Cell–like Features
Authors: Geary Lauren A. , Nash Kevin A. , Adisetiyo Helty , Liang Mengmeng , Liao Chun-Peng , Jeong Joseph H. , Zandi Ebrahim , Roy-Burman Pradip
Published: April 2023

Abstract
Annexin A1 (AnxA1), a phospholipid-binding protein and regulator of glucocorticoid-induced inflammatory signaling, has implications in cancer. Here, a role for AnxA1 in prostate adenocarcinoma was determined using primary cultures and a tumor cell line (cE1), all derived from the conditional Pten deletion mouse model of prostate cancer. AnxA1 secretion by prostate-derived cancer-associated fibroblasts (CAF) was significantly higher than by normal prostate fibroblasts (NPF). Prostate tumor cells were sorted to enrich for epithelial subpopulations based on nonhematopoietic lineage, high SCA-1, and high or medium levels of CD49f. Compared with controls, AnxA1 enhanced stem cell–like properties in high- and medium-expression subpopulations of sorted cE1 and primary cells, in vitro, through formation of greater number of spheroids with increased complexity, and in vivo, through generation of more, larger, and histologically complex glandular structures, along with increased expression of p63, a basal/progenitor marker. The differentiated medium-expression subpopulations from cE1 and primary cells were most susceptible to gain stem cell–like properties as shown by increased spheroid and glandular formation. Further supporting this increased plasticity, AnxA1 was shown to regulate epithelial-to-mesenchymal transition in cE1 cells. These results suggest that CAF-secreted AnxA1 contributes to tumor stem cell dynamics via two separate but complementary pathways: induction of a dedifferentiation process leading to generation of stem-like cells from a subpopulation of cancer epithelial cells and stimulation of proliferation and differentiation of the cancer stem-like cells.

Implications: AnxA1 participates in a paradigm in which malignant prostate epithelial cells that are not cancer stem cells are induced to gain cancer stem cell–like properties. Mol Cancer Res; 12(4); 607–21. ©2014 AACR.
Data from Identification of an “Exceptional Responder” Cell Line to MEK1 Inhibition: Clinical Implications for MEK-Targeted Therapy
Authors: Gannon Hugh S. , Kaplan Nathan , Tsherniak Aviad , Vazquez Francisca , Weir Barbara A. , Hahn William C. , Meyerson Matthew
Published: April 2023

Abstract
The identification of somatic genetic alterations that confer sensitivity to pharmacologic inhibitors has led to new cancer therapies. To identify mutations that confer an exceptional dependency, shRNA-based loss-of-function data were analyzed from a dataset of numerous cell lines to reveal genes that are essential in a small subset of cancer cell lines. Once these cell lines were determined, detailed genomic characterization from these cell lines was utilized to ascertain the genomic aberrations that led to this extreme dependency. This method, in a large subset of lung cancer cell lines, yielded a single lung adenocarcinoma cell line, NCI-H1437, which is sensitive to RNA interference of MAP2K1 expression. Notably, NCI-H1437 is the only lung cancer cell line included in the dataset with a known activating mutation in MAP2K1 (Q56P). Subsequent validation using shRNA and CRISPR-Cas9 confirmed MAP2K1 dependency. In vitro and in vivo inhibitor studies established that NCI-H1437 cells are sensitive to MEK1 inhibitors, including the FDA-approved drug trametinib. Like NCI-H1437 cells, the MAP2K1-mutant cell lines SNU-C1 (colon) and OCUM-1 (gastric) showed decreased viability after MAP2K1 depletion via Cas9-mediated gene editing. Similarly, these cell lines were particularly sensitive to trametinib treatment compared with control cell lines. On the basis of these data, cancers that harbor driver mutations in MAP2K1 could benefit from treatment with MEK1 inhibitors. Furthermore, this functional data mining approach provides a general method to experimentally test genomic features that confer dependence in tumors.

Implications: Cancers with an activated RAS/MAPK pathway driven by oncogenic MAP2K1 mutations may be particularly sensitive to MEK1 inhibitor treatments. Mol Cancer Res; 14(2); 207–15. ©2015 AACR.
Data from Hypoxic Stress Facilitates Acute Activation and Chronic Downregulation of Fanconi Anemia Proteins
Authors: Scanlon Susan E. , Glazer Peter M.
Published: April 2023

Abstract
Hypoxia induces genomic instability through replication stress and dysregulation of vital DNA repair pathways. The Fanconi anemia (FA) proteins, FANCD2 and FANCI, are key members of a DNA repair pathway that responds to replicative stress, suggesting that they undergo regulation by hypoxic conditions. Here acute hypoxic stress activates the FA pathway via ubiquitination of FANCD2 and FANCI in an ATR-dependent manner. In addition, the presence of an intact FA pathway is required for preventing hypoxia-induced DNA damage measurable by the comet assay, limiting the accumulation of γH2AX (a marker of DNA damage or stalled replication), and protecting cells from hypoxia-induced apoptosis. Furthermore, prolonged hypoxia induces transcriptional repression of FANCD2 in a manner analogous to the hypoxic downregulation of BRCA1 and RAD51. Thus, hypoxia-induced FA pathway activation plays a key role in maintaining genome integrity and cell survival, while FA protein downregulation with prolonged hypoxia contributes to genomic instability.

Implications: This work highlights the critical role of the FA pathway in response to hypoxic stress and identifies the pathway as a therapeutic target under hypoxic conditions. Mol Cancer Res; 12(7); 1016–28. ©2014 AACR.
Data from Synergistic Loss of Prostate Cancer Cell Viability by Coinhibition of HDAC and PARP
Authors: Chao Olivia S. , Goodman Oscar B.
Published: April 2023

Abstract
Tumors with BRCA germline mutations are defective in repairing DNA double-strand breaks (DSB) through homologous recombination (HR) pathways, making them sensitive to PARP inhibitors (PARPi). However, BRCA germline mutations are rare in prostate cancer limiting the ability to therapeutically target these pathways. This study investigates whether histone deacetylase (HDAC) inhibitors (HDACi), reported to modulate DSB repair pathways in sporadic cancers, can downregulate DSB repair pathways and sensitize prostate cancer cells to PARPi. Prostate cancer cells cotreated with the HDAC inhibitor, suberoylanilide hydroxamic acid (SAHA) and the PARPi, olaparib, demonstrated a synergistic decrease in cell viability compared with single-agent treatment (combination index < 0.9), whereas normal prostatic cells did not. Similarly, clonogenicity was significantly decreased after cotreatment. Flow cytometric cell-cycle analysis and Annexin-V staining revealed significant apoptosis upon treatment with SAHA+olaparib. This coincided with increased DNA damage observed by immunofluorescence microscopy analysis of γH2AX foci, a marker of DSBs. In addition, immunoblot analysis showed a significant and persistent increase in nuclear γH2AX levels. Both SAHA and olaparib downregulated the expression of HR-related proteins, BRCA1 and RAD51, whereas SAHA + olaparib had an additive effect on RAD51. Silencing RAD51 sensitized prostate cancer cells to SAHA and olaparib alone. Collectively, cotreatment with HDACi and PARPi downregulated HR-related protein expression and concomitantly increased DNA damage, resulting in prostate cancer cell death.

Implications: These findings provide a strong rationale for supporting the use of combined HDAC and PARP inhibition in treating advanced prostate cancer. Mol Cancer Res; 12(12); 1755–66. ©2014 AACR.
Data from Delineation of a FOXA1/ERα/AGR2 Regulatory Loop That Is Dysregulated in Endocrine Therapy–Resistant Breast Cancer
Authors: Wright Tricia M. , Wardell Suzanne E. , Jasper Jeff S. , Stice James P. , Safi Rachid , Nelson Erik R. , McDonnell Donald P.
Published: April 2023

Abstract
Tamoxifen, a selective estrogen receptor (ER) modulator (SERM), remains a frontline clinical therapy for patients with ERα-positive breast cancer. However, the relatively rapid development of resistance to this drug in the metastatic setting remains an impediment to a durable response. Although drug resistance likely arises by many different mechanisms, the consensus is that most of the implicated pathways facilitate the outgrowth of a subpopulation of cancer cells that can either recognize tamoxifen as an agonist or bypass the regulatory control of ERα. Notable in this regard is the observation here and in other studies that expression of anterior gradient homology 2 (AGR2), a known proto-oncogene and disulfide isomerase, was induced by both estrogen (17β-estradiol, E2) and 4-hydroxytamoxifen (4OHT) in breast cancer cells. The importance of AGR2 expression is highlighted here by the observation that (i) its knockdown inhibited the growth of both tamoxifen-sensitive and -resistant breast cancer cells and (ii) its increased expression enhanced the growth of ERα-positive tumors in vivo and increased the migratory capacity of breast cancer cells in vitro. Interestingly, as with most ERα target genes, the expression of AGR2 in all breast cancer cells examined requires the transcription factor FOXA1. However, in tamoxifen-resistant cells, the expression of AGR2 occurs in a constitutive manner, requiring FOXA1, but loses its dependence on ER. Taken together, these data define the importance of AGR2 in breast cancer cell growth and highlight a mechanism where changes in FOXA1 activity obviate the need for ER in the regulation of this gene.

Implications: These findings reveal the transcriptional interplay between FOXA1 and ERα in controlling AGR2 during the transition from therapy-sensitive to -resistant breast cancer and implicate AGR2 as a relevant therapeutic target. Mol Cancer Res; 12(12); 1829–39. ©2014 AACR.
Data from CITED2 Modulates Breast Cancer Metastatic Ability through Effects on IKKα
Authors: Jayaraman Swaathi , Doucet Michele , Lau Wen Min , Kominsky Scott L.
Published: April 2023

Abstract
Previously, we identified the transcriptional coactivator CITED2 as a potential facilitator of bone metastasis using a murine mammary cancer model. Extending these studies to human breast cancer, it was observed that CITED2 mRNA expression was significantly elevated in patient specimens of metastatic breast cancer relative to primary tumors, with highest levels in metastasis to bone relative to non-bone sites. To further evaluate CITED2 functions in breast cancer metastasis, CITED2 expression was stably reduced in the human breast cancer cell lines MDA-MB-231 and MDA-MB-468, which are metastatic in animal models. While CITED2 knockdown had no effect on cell proliferation, cell migration and invasion were significantly reduced, as was the establishment of metastasis following intracardiac administration in athymic nude mice. To explore the mechanism behind these effects, gene expression following CITED2 knockdown in MDA-MB-231 cells by cDNA microarray was performed. As confirmed at the mRNA and protein levels in both MDA-MB-231 and MDA-MB-468 cells, expression of the NF-κB regulator IKKα was significantly reduced, along with several NF-κB targets with known roles in metastasis (OPN, MMP9, uPA, SPARC, IL11, and IL1β). Furthermore, ChIP assay revealed recruitment of CITED2 to the promoter of IKKα, indicating a direct role in regulating its expression. Consistent with reduced IKKα expression, CITED2 knockdown inhibited both canonical and noncanonical NF-κB signaling. Finally, restoration of IKKα expression following CITED2 knockdown in MDA-MB-231 and MDA-MB-468 cells rescued their invasive ability. Collectively, these data demonstrate that CITED2 modulates metastatic ability in human breast cancer cells, at least in part, through the regulation of IKKα.

Implications: The current study highlights the role of CITED2 in facilitating breast cancer metastasis, partly via regulation of IKKα. Mol Cancer Res; 14(8); 730–9. ©2016 AACR.
Data from Chemotherapy-Induced Inflammatory Gene Signature and Protumorigenic Phenotype in Pancreatic CAFs via Stress-Associated MAPK
Authors: Toste Paul A. , Nguyen Andrew H. , Kadera Brian E. , Duong Mindy , Wu Nanping , Gawlas Irmina , Tran Linh M. , Bikhchandani Mihir , Li Luyi , Patel Sanjeet G. , Dawson David W. , Donahue Timothy R.
Published: April 2023

Abstract
Pancreatic ductal adenocarcinoma (PDAC) has a characteristically dense stroma comprised predominantly of cancer-associated fibroblasts (CAF). CAFs promote tumor growth, metastasis, and treatment resistance. This study aimed to investigate the molecular changes and functional consequences associated with chemotherapy treatment of PDAC CAFs. Chemoresistant immortalized CAFs (R-CAF) were generated by continuous incubation in gemcitabine. Gene expression differences between treatment-naïve CAFs (N-CAF) and R-CAFs were compared by array analysis. Functionally, tumor cells (TC) were exposed to N-CAF– or R-CAF–conditioned media and assayed for migration, invasion, and viability in vitro. Furthermore, a coinjection (TC and CAF) model was used to compare tumor growth in vivo. R-CAFs increased TC viability, migration, and invasion compared with N-CAFs. In vivo, TCs coinjected with R-CAFs grew larger than those accompanied by N-CAFs. Genomic analysis demonstrated that R-CAFs had increased expression of various inflammatory mediators, similar to the previously described senescence-associated secretory phenotype (SASP). In addition, SASP mediators were found to be upregulated in response to short duration treatment with gemcitabine in both immortalized and primary CAFs. Inhibition of stress-associated MAPK signaling (P38 MAPK or JNK) attenuated SASP induction as well as the tumor-supportive functions of chemotherapy-treated CAFs in vitro and in vivo. These results identify a negative consequence of chemotherapy on the PDAC microenvironment that could be targeted to improve the efficacy of current therapeutic regimens.

Implications: Chemotherapy treatment of pancreatic cancer–associated fibroblasts results in a proinflammatory response driven by stress-associated MAPK signaling that enhances tumor cell growth and invasiveness. Mol Cancer Res; 14(5); 437–47. ©2016 AACR.
Data from IGFBP3 Modulates Lung Tumorigenesis and Cell Growth through IGF1 Signaling
Authors: Wang Yong Antican , Sun Yunguang , Palmer Joshua , Solomides Charalambos , Huang Li-Ching , Shyr Yu , Dicker Adam P. , Lu Bo
Published: April 2023

Abstract
Insulin-like growth factor binding protein 3 (IGFBP3) modulates cell growth through IGF-dependent and -independent mechanisms. Reports suggest that the serum levels of IGFBP3 are associated with various cancers and that IGFBP3 expression is significantly decreased in cisplatin (CDDP)-resistant lung cancer cells. Based on these findings, we investigated whether Igfbp3 deficiency accelerates mouse lung tumorigenesis and if expression of IGFBP3 enhances CDDP response by focusing on the IGF1 signaling cascade. To this end, an Igfbp3-null mouse model was generated in combination with KrasG12D to compare the tumor burden. Then, IGF-dependent signaling was assessed after expressing wild-type or a mutant IGFBP3 without IGF binding capacity in non–small cell lung cancer (NSCLC) cells. Finally, the treatment response to CDDP chemotherapy was evaluated under conditions of IGFBP3 overexpression. Igfbp3-null mice had increased lung tumor burden (>2-fold) and only half of human lung cancer cells survived after expression of IGFBP3, which corresponded to increased cleaved caspase-3 (10-fold), inactivation of IGF1 and MAPK signaling. In addition, overexpression of IGFBP3 increased susceptibility to CDDP treatment in lung cancer cells. These results, for the first time, demonstrate that IGFBP3 mediates lung cancer progression in a KrasG12D mouse model. Furthermore, overexpression of IGFBP3 induced apoptosis and enhanced cisplatin response in vitro and confirmed that the suppression is in part by blocking IGF1 signaling.

Implications: These findings reveal that IGFBP3 is effective in lung cancer cells with high IGF1 signaling activity and imply that relevant biomarkers are essential in selecting lung cancer patients for IGF1-targeted therapy. Mol Cancer Res; 15(7); 896–904. ©2017 AACR.
Data from Integrative Epigenetic and Gene Expression Analysis of Renal Tumor Progression to Metastasis
Authors: Nam Hye-Young , Chandrashekar Darshan S. , Kundu Anirban , Shelar Sandeep , Kho Eun-Young , Sonpavde Guru , Naik Gurudatta , Ghatalia Pooja , Livi Carolina B. , Varambally Sooryanarayana , Sudarshan Sunil
Published: April 2023

Abstract
The Cancer Genome Atlas (TCGA) and other large-scale genomic data pipelines have been integral to the current understanding of the molecular events underlying renal cell carcinoma (RCC). These data networks have focused mostly on primary RCC, which often demonstrates indolent behavior. However, metastatic disease is the major cause of mortality associated with RCC and data sets examining metastatic tumors are sparse. Therefore, a more comprehensive analysis of gene expression and DNA methylome profiling of metastatic RCC in addition to primary RCC and normal kidney was performed. Integrative analysis of the methylome and transcriptome identified over 30 RCC-specific genes whose mRNA expression inversely correlated with promoter methylation, including several known targets of hypoxia inducible factors. Notably, genes encoding several metabolism-related proteins were identified as differentially regulated via methylation including hexokinase 2, aldolase C, stearoyl-CoA desaturase, and estrogen-related receptor-γ (ESRRG), which has a known role in the regulation of nuclear-encoded mitochondrial metabolism genes. Several gene expression changes could portend prognosis in the TCGA cohort. Mechanistically, ESRRG loss occurs via DNA methylation and histone repressive silencing mediated by the polycomb repressor complex 2. Restoration of ESRRG in RCC lines suppresses migratory and invasive phenotypes independently of its canonical role in mitochondrial metabolism.
Implications:
Collectively, these data provide significant insight into the biology of aggressive RCC and demonstrate a novel role for DNA methylation in the promotion of HIF signaling and invasive phenotypes in renal cancer.
Data from Diffuse Intrinsic Pontine Glioma Cells Are Vulnerable to Mitotic Abnormalities Associated with BMI-1 Modulation
Authors: Senthil Kumar Shiva , Sengupta Satarupa , Zhu Xiaoting , Mishra Deepak Kumar , Phoenix Timothy , Dyer Lisa , Fuller Christine , Stevenson Charles B. , DeWire Mariko , Fouladi Maryam , Drissi Rachid
Published: April 2023

Abstract
Diffuse intrinsic pontine glioma (DIPG) is a poor-prognosis pediatric brain tumor with a median survival of less than 1 year. No effective therapy is currently available, and no therapeutic advances have been made in several decades. We have previously identified BMI-1 as a potential therapeutic target in DIPG and have shown that BMI-1 is highly expressed in DIPG tumors regardless of histone 3 subtype. In the present study, we show that the modulation of BMI-1 leads to DNA damage, M phase cell-cycle arrest, chromosome scattering, and cell death. Interestingly, EZH2 inhibition did not alter these effects. Furthermore, modulation of BMI-1 sensitizes DIPG patient-derived stem-like cells to ionizing radiation (IR). Treatment of DIPG stem-like cells with PTC596, a BMI-1 modulator, and IR impairs the kinetics of DNA damage response (DDR). Both DDR foci formation and resolution were delayed, resulting in further reduction in cell viability compared with either treatment alone. In vivo, treatment of mice bearing DIPG xenografts with PTC596 leads to decreased tumor volume and growth kinetics, increased intratumoral apoptosis, and sustained animal survival benefit. Gene expression analysis indicates that BMI-1 expression correlates positively with DIPG stemness and BMI-1 signature. At the single-cell level, the analysis reveals that BMI-1 pathway is upregulated in undifferentiated cells and positively correlates with stemness in DIPG tumors.
Implications:
Together, our findings indicate that BMI-1 modulation is associated with mitotic abnormalities, impaired DDR, and cell death, supporting the combination of BMI-1 modulation and radiation as a promising novel therapy for children with DIPG.
Data from T-Cell Deletion of MyD88 Connects IL17 and IκBζ to RAS Oncogenesis
Authors: Cataisson Christophe , Salcedo Rosalba , Michalowski Aleksandra M. , Klosterman Mary , Naik Shruti , Li Luowei , Pan Michelle J. , Sweet Amalia , Chen Jin-Qiu , Kostecka Laurie G. , Karwan Megan , Smith Loretta , Dai Ren-Ming , Stewart C. Andrew , Lyakh Lyudmila , Hsieh Wang-Ting , Khan Asra , Yang Howard , Lee Maxwell , Trinchieri Giorgio , Yuspa Stuart H.
Published: April 2023

Abstract
Cancer development requires a favorable tissue microenvironment. By deleting Myd88 in keratinocytes or specific bone marrow subpopulations in oncogenic RAS-mediated skin carcinogenesis, we show that IL17 from infiltrating T cells and IκBζ signaling in keratinocytes are essential to produce a permissive microenvironment and tumor formation. Both normal and RAS-transformed keratinocytes respond to tumor promoters by activating canonical NF-κB and IκBζ signaling, releasing specific cytokines and chemokines that attract Th17 cells through MyD88-dependent signaling in T cells. The release of IL17 into the microenvironment elevates IκBζ in normal and RAS-transformed keratinocytes. Activation of IκBζ signaling is required for the expression of specific promoting factors induced by IL17 in normal keratinocytes and constitutively expressed in RAS-initiated keratinocytes. Deletion of Nfkbiz in keratinocytes impairs RAS-mediated benign tumor formation. Transcriptional profiling and gene set enrichment analysis of IκBζ−deficient RAS-initiated keratinocytes indicate that IκBζ signaling is common for RAS transformation of multiple epithelial cancers. Probing The Cancer Genome Atlas datasets using this transcriptional profile indicates that reduction of IκBζ signaling during cancer progression associates with poor prognosis in RAS-driven human cancers.
Implications:
The paradox that elevation of IκBζ and stimulation of IκBζ signaling through tumor extrinsic factors is required for RAS-mediated benign tumor formation while relative IκBζ expression is reduced in advanced cancers with poor prognosis implies that tumor cells switch from microenvironmental dependency early in carcinogenesis to cell-autonomous pathways during cancer progression.
Data from Estrogen-Induced Apoptosis in Breast Cancers Is Phenocopied by Blocking Dephosphorylation of Eukaryotic Initiation Factor 2 Alpha (eIF2α) Protein
Authors: Sengupta Surojeet , Sevigny Catherine M. , Bhattacharya Poulomi , Jordan V. Craig , Clarke Robert
Published: April 2023

Abstract
Approximately 30% of aromatase-inhibitor–resistant, estrogen receptor–positive patients with breast cancer benefit from treatment with estrogen. This enigmatic estrogen action is not well understood and how it occurs remains elusive. Studies indicate that the unfolded protein response and apoptosis pathways play important roles in mediating estrogen-triggered apoptosis. Using MCF7:5C cells, which mimic aromatase inhibitor resistance, and are hypersensitive to estrogen as evident by induction of apoptosis, we define increased global protein translational load as the trigger for estrogen-induced apoptosis. The protein kinase RNA-like endoplasmic reticulum kinase pathway was activated followed by increased phosphorylation of eukaryotic initiation factor-2 alpha (eIF2α). These actions block global protein translation but preferentially allow high expression of specific transcription factors, such as activating transcription factor 4 and C/EBP homologous protein that facilitate apoptosis. Notably, we recapitulated this phenotype of MCF7:5C in two other endocrine therapy–resistant cell lines (MCF7/LCC9 and T47D:A18/4-OHT) by increasing the levels of phospho-eIF2α using salubrinal to pharmacologically inhibit the enzymes responsible for dephosphorylation of eIF2α, GADD34, and CReP. RNAi-mediated ablation of these genes induced apoptosis that used the same signaling as salubrinal treatment. Moreover, combining 4-hydroxy tamoxifen with salubrinal enhanced apoptotic potency.
Implications:
These results not only elucidate the mechanism of estrogen-induced apoptosis but also identify a drugable target for potential therapeutic intervention that can mimic the beneficial effect of estrogen in some breast cancers.
Data from Alectinib Resistance in ALK-Rearranged Lung Cancer by Dual Salvage Signaling in a Clinically Paired Resistance Model
Authors: Tsuji Takahiro , Ozasa Hiroaki , Aoki Wataru , Aburaya Shunsuke , Funazo Tomoko , Furugaki Koh , Yoshimura Yasushi , Ajimizu Hitomi , Okutani Ryoko , Yasuda Yuto , Nomizo Takashi , Uemasu Kiyoshi , Hasegawa Koichi , Yoshida Hironori , Yagi Yoshitaka , Nagai Hiroki , Sakamori Yuichi , Ueda Mitsuyoshi , Hirai Toyohiro , Kim Young Hak
Published: April 2023

Abstract
The mechanisms responsible for the development of resistance to alectinib, a second-generation anaplastic lymphoma kinase (ALK) inhibitor, are still unclear, and few cell lines are currently available for investigating ALK-rearranged lung cancer. To identify the mechanisms underlying acquired resistance to alectinib, two patient-derived cell lines were established from an alectinib-naïve ALK-rearranged lung cancer and then after development of alectinib resistance. The properties acquired during treatments were detected by comparisons of the two cell lines, and then functional analyses were performed. Coactivation of c-Src and MET was identified after the development of alectinib resistance. Combinatorial therapy against Src and MET significantly restored alectinib sensitivity in vitro (17.2-fold). Increased apoptosis, reduction of tumor volume, and inhibition of MAPK and PI3K/AKT signaling molecules for proliferation and survival were observed when the three kinases (Src, MET, and ALK) were inhibited. A patient-derived xenograft from the alectinib-resistant cells indicated that combination therapy with a saracatinib and crizotinib significantly decreased tumor size in vivo. To confirm the generality, a conventional alectinib-resistant cell line model (H2228-AR1S) was established from NCI-H2228 cells (EML4-ALK variant 3a/b). In H2228-AR1S, combination inhibition of Src and MET also restored alectinib sensitivity. These data reveal that dual salvage signaling from MET and Src is a potential therapeutic target in alectinib-resistant patients.
Implications:
This study demonstrates the feasibility to elucidate personalized drug-resistance mechanisms from individual patient samples.
Data from Modulation of Mutant KrasG12D-Driven Lung Tumorigenesis In Vivo by Gain or Loss of PCDH7 Function
Authors: Zhou Xiaorong , Padanad Mahesh S. , Evers Bret M. , Smith Bethany , Novaresi Nicole , Suresh Shruthy , Richardson James A. , Stein Emily , Zhu Jingfei , Hammer Robert E. , O'Donnell Kathryn A.
Published: April 2023

Abstract
PROTOCADHERIN 7 (PCDH7), a transmembrane receptor and member of the Cadherin superfamily, is frequently overexpressed in lung adenocarcinoma and is associated with poor clinical outcome. Although PCDH7 was recently shown to promote transformation and facilitate brain metastasis in lung and breast cancers, decreased PCDH7 expression has also been documented in colorectal, gastric, and invasive bladder cancers. These data suggest context-dependent functions for PCDH7 in distinct tumor types. Given that PCDH7 is a potentially targetable molecule on the surface of cancer cells, further investigation of its role in tumorigenesis in vivo is needed to evaluate the therapeutic potential of its inhibition. Here, we report the analysis of novel PCDH7 gain- and loss-of-function mouse models and provide compelling evidence that this cell-surface protein acts as a potent lung cancer driver. Employing a Cre-inducible transgenic allele, we demonstrated that enforced PCDH7 expression significantly accelerates KrasG12D-driven lung tumorigenesis and potentiates MAPK pathway activation. Furthermore, we performed in vivo somatic genome editing with CRISPR/Cas9 in KrasLSL-G12D; Tp53fl/fl (KP) mice to assess the consequences of PCDH7 loss of function. Inactivation of PCDH7 in KP mice significantly reduced lung tumor development, prolonged survival, and diminished phospho-activation of ERK1/2. Together, these findings establish a critical oncogenic function for PCDH7 in vivo and highlight the therapeutic potential of PCDH7 inhibition for lung cancer. Moreover, given recent reports of elevated or reduced PCDH7 in distinct tumor types, the new inducible transgenic model described here provides a robust experimental system for broadly elucidating the effects of PCDH7 overexpression in vivo.
Implications:
In this study, we establish a critical oncogenic function for PCDH7 in vivo using novel mouse models and CRISPR/Cas9 genome editing, and we validate the therapeutic potential of PCDH7 inhibition for lung cancer.
Data from The Landscape of Isoform Switches in Human Cancers
Authors: Vitting-Seerup Kristoffer , Sandelin Albin
Published: April 2023

Abstract
Alternative usage of transcript isoforms from the same gene has been hypothesized as an important feature in cancers. However, differential usage of gene transcripts between conditions (isoform switching) has not been comprehensively characterized in and across cancer types. To this end, we developed methods for identification and visualization of isoform switches with predicted functional consequences. Using these methods, we characterized isoform switching in RNA-seq data from >5,500 cancer patients covering 12 solid cancer types. Isoform switches with potential functional consequences were common, affecting approximately 19% of multiple transcript genes. Among these, isoform switches leading to loss of DNA sequence encoding protein domains were more frequent than expected, particularly in pancancer switches. We identified several isoform switches as powerful biomarkers: 31 switches were highly predictive of patient survival independent of cancer types. Our data constitute an important resource for cancer researchers, available through interactive web tools. Moreover, our methods, available as an R package, enable systematic analysis of isoform switches from other RNA-seq datasets.

Implications: This study indicates that isoform switches with predicted functional consequences are common and important in dysfunctional cells, which in turn means that gene expression should be analyzed at the isoform level.

Visual Overview: http://mcr.aacrjournals.org/content/molcanres/15/9/1206/F1.large.jpg. Mol Cancer Res; 15(9); 1206–20. ©2017 AACR.
Data from A Leukocyte Infiltration Score Defined by a Gene Signature Predicts Melanoma Patient Prognosis
Authors: Zhao Yanding , Schaafsma Evelien , Gorlov Ivan P. , Hernando Eva , Thomas Nancy E. , Shen Ronglai , Turk Mary Jo , Berwick Marianne , Amos Christopher I. , Cheng Chao
Published: April 2023

Abstract
Melanoma is the most aggressive type of skin cancer in the United States with an increasing incidence. Melanoma lesions often exhibit high immunogenicity, with infiltrating immune cells playing important roles in regression of tumors occurring spontaneously or caused by therapeutic treatment. Computational and experimental methods have been used to estimate the abundance of immune cells in tumors, but their applications are limited by the requirement of large gene sets or multiple antibodies. Although the prognostic role of immune cells has been appreciated, a systematic investigation of their association with clinical factors, genomic features, prognosis and treatment response in melanoma is still lacking. This study, identifies a 25-gene signature based on RNA-seq data from The Cancer Genome Atlas (TCGA)—Skin Cutaneous Melanoma (TCGA-SKCM) dataset. This signature was used to calculate sample-specific Leukocyte Infiltration Scores (LIS) in six independent melanoma microarray datasets and scores were found to vary substantially between different melanoma lesion sites and molecular subtypes. For metastatic melanoma, LIS was prognostic in all datasets with high LIS being associated with good survival. The current approach provided additional prognostic information over established clinical factors, including age, tumor stage, and gender. In addition, LIS was predictive of patient survival in stage III melanoma, and treatment efficacy of tumor-specific antigen vaccine.
Implications:
This study identifies a 25-gene signature that effectively estimates the level of immune cell infiltration in melanoma, which provides a robust biomarker for predicting patient prognosis.
Data from FoxO3a Mediates the Inhibitory Effects of the Antiepileptic Drug Lamotrigine on Breast Cancer Growth
Authors: Pellegrino Michele , Rizza Pietro , Nigro Alessandra , Ceraldi Rosangela , Ricci Elena , Perrotta Ida , Aquila Saveria , Lanzino Marilena , Andò Sebastiano , Morelli Catia , Sisci Diego
Published: April 2023

Abstract
Breast cancer is a complex and heterogeneous disease, with distinct histologic features dictating the therapy. Although the clinical outcome of breast cancer patients has been considerably improved, the occurrence of resistance to common endocrine and chemotherapy treatments remains the major cause of relapse and mortality. Thus, efforts in identifying new molecules to be employed in breast cancer therapy are needed. As a “faster” alternative to reach this aim, we evaluated whether lamotrigine, a broadly used anticonvulsant, could be “repurposed” as an antitumoral drug in breast cancer. Our data show that lamotrigine inhibits the proliferation, the anchorage-dependent, and independent cell growth in breast cancer cells (BCC), including hormone-resistant cell models. These effects were associated with cell-cycle arrest and modulation of related proteins (cyclin D1, cyclin E, p27Kip1, and p21Waf1/Cip1), all target genes of FoxO3a, an ubiquitous transcription factor negatively regulated by AKT. Lamotrigine also increases the expression of another FoxO3a target, PTEN, which, in turn, downregulates the PI3K/Akt signaling pathway, with consequent dephosphorylation, thus activation, of FoxO3a. Moreover, lamotrigine induces FoxO3a expression by increasing its transcription through FoxO3a recruitment on specific FHRE located on its own promoter, in an autoregulatory fashion. Finally, lamotrigine significantly reduced tumor growth in vivo, increasing FoxO3a expression.

Implications: The anticonvulsant drug lamotrigine shows strong antiproliferative activity on breast cancer, both in vitro and in vivo. Thus, drug repurposing could represent a valuable option for a molecularly targeted therapy in breast cancer patients. Mol Cancer Res; 16(6); 923–34. ©2018 AACR.
Data from Transient Telomerase Inhibition with Imetelstat Impacts DNA Damage Signals and Cell-Cycle Kinetics
Authors: Thompson Connor A.H. , Gu Alice , Yang Sunny Y. , Mathew Veena , Fleisig Helen B , Wong Judy M.Y.
Published: April 2023

Abstract
Telomerase is the ribonucleoprotein reverse transcriptase that catalyzes the synthesis of telomeres at the ends of linear chromosomes and contributes to proper telomere-loop (T-loop) formation. Formation of the T-loop, an obligate step before cell division can proceed, requires the generation of a 3′-overhang on the G-rich strand of telomeric DNA via telomerase or C-strand specific nucleases. Here, it is discovered that telomerase activity is critical for efficient cell-cycle progression using transient chemical inhibition by the telomerase inhibitor, imetelstat. Telomerase inhibition changed cell cycle kinetics and increased the proportion of cells in G2-phase, suggesting delayed clearance through this checkpoint. Investigating the possible contribution of unstructured telomere ends to these cell-cycle distribution changes, it was observed that imetelstat treatment induced γH2AX DNA damage foci in a subset of telomerase-positive cells but not telomerase-negative primary human fibroblasts. Chromatin-immunoprecipitation with γH2AX antibodies demonstrated imetelstat treatment-dependent enrichment of this DNA damage marker at telomeres. Notably, the effects of telomerase inhibition on cell cycle profile alterations were abrogated by pharmacological inhibition of the DNA-damage-repair transducer, ATM. Also, imetelstat potentiation of etoposide, a DNA-damaging drug that acts preferentially during S–G2 phases of the cell cycle, depends on functional ATM signaling. Thus, telomerase inhibition delays the removal of ATM-dependent DNA damage signals from telomeres in telomerase-positive cancer cells and interferes with cell cycle progression through G2.

Implications: This study demonstrates that telomerase activity directly facilitates the progression of the cell cycle through modulation of transient telomere dysfunction signals. Mol Cancer Res; 16(8); 1215–25. ©2018 AACR.
Data from A Ca2+-ATPase Regulates E-cadherin Biogenesis and Epithelial–Mesenchymal Transition in Breast Cancer Cells
Authors: Dang Donna K. , Makena Monish Ram , Llongueras José P. , Prasad Hari , Ko Myungjun , Bandral Manuj , Rao Rajini
Published: April 2023

Abstract
Progression of benign tumors to invasive, metastatic cancer is accompanied by the epithelial-to-mesenchymal transition (EMT), characterized by loss of the cell-adhesion protein E-cadherin. Although silencing mutations and transcriptional repression of the E-cadherin gene have been widely studied, not much is known about posttranslational regulation of E-cadherin in tumors. We show that E-cadherin is tightly coexpressed with the secretory pathway Ca2+-ATPase isoform 2, SPCA2 (ATP2C2), in breast tumors. Loss of SPCA2 impairs surface expression of E-cadherin and elicits mesenchymal gene expression through disruption of cell adhesion in tumorspheres and downstream Hippo-YAP signaling. Conversely, ectopic expression of SPCA2 in triple-negative breast cancer elevates baseline Ca2+ and YAP phosphorylation, enhances posttranslational expression of E-cadherin, and suppresses mesenchymal gene expression. Thus, loss of SPCA2 phenocopies loss of E-cadherin in the Hippo signaling pathway and EMT–MET transitions, consistent with a functional role for SPCA2 in E-cadherin biogenesis. Furthermore, we show that SPCA2 suppresses invasive phenotypes, including cell migration in vitro and tumor metastasis in vivo. Based on these findings, we propose that SPCA2 functions as a key regulator of EMT and may be a potential therapeutic target for treatment of metastatic cancer.
Implications:
Posttranslational control of E-cadherin and the Hippo pathway by calcium signaling regulates EMT in breast cancer cells.
Data from Activation of PPARγ in Myeloid Cells Promotes Progression of Epithelial Lung Tumors through TGFβ1
Authors: Sippel Trisha R. , Johnson Amber M. , Li Howard Y. , Hanson Dwight , Nguyen Teresa T. , Bullock Bonnie L. , Poczobutt Joanna M. , Kwak Jeff W. , Kleczko Emily K. , Weiser-Evans Mary C. , Nemenoff Raphael A.
Published: April 2023

Abstract
Lung cancer is a heterogeneous disease in which patient-specific treatments are desirable and the development of targeted therapies has been effective. Although mutations in KRAS are frequent in lung adenocarcinoma, there are currently no targeted agents against KRAS. Using a mouse lung adenocarcinoma cell line with a Kras mutation (CMT167), we previously showed that PPARγ activation in lung cancer cells inhibits cell growth in vitro yet promotes tumor progression when activated in myeloid cells of the tumor microenvironment. Here, we report that PPARγ activation in myeloid cells promotes the production of TGFβ1, which, in turn, acts on CMT167 cancer cells to increase migration and induce an epithelial–mesenchymal transition (EMT). Targeting TGFβ1 signaling in CMT167 cells prevented their growth and metastasis in vivo. Similarly, another mouse lung adenocarcinoma cell line with a Kras mutation, LLC, induced TGFβ1 in myeloid cells through PPARγ activation. However, LLC cells are more mesenchymal and did not undergo EMT in response to TGFβ1, nor did LLC require TGFβ1 signaling for metastasis in vivo. Converting CMT167 cells to a mesenchymal phenotype through overexpression of ZEB1 made them unresponsive to TGFβ1 receptor inhibition. The ability of TGFβ1 to induce EMT in lung tumors may represent a critical process in cancer progression. We propose that TGFβ receptor inhibition could provide an additional treatment option for KRAS-mutant epithelial lung tumors.

Implications: This study suggests that TGFβ receptor inhibitors may be an effective therapy in a subset of KRAS-mutant patients with non–small cell lung cancer, which show an epithelial phenotype.