Abstract 3081: KDM1A/LSD1 inhibition enhances estrogen receptor beta mediated tumor suppression in ovarian cancer

Introduction: Ovarian cancer (OCa) is the deadliest of all gynecologic cancers. Recent studies suggest that OCa cells express estrogen receptor beta (ERb), which functions as a tumor suppressor. However, ERb expression decreases during tumor progression and under the selection pressure of chemotherapy; this decrease occurs via epigenetic mechanisms and is inversely correlated with OCa progression. Lysine-specific histone demethylase 1A (KDM1A/LSD1), an epigenetic modifier, is highly overexpressed in OCa. However, it is not known if KDM1A regulates ERb expression and its corresponding tumor suppressor functions. In this study, we explored the hypotheses that KDM1A inhibits ERb expression and function and that ERb-mediated tumor suppression in OCa is enhanced by KDM1A inhibition.

Methods: Transduction of KDM1A-specific shRNA or gRNA was used to generate KDM1A knockdown (KD) or knockout (KO) cells, respectively. Cell viability, survival, apoptosis, and invasion assays were used to determine the impact of KDM1A knockdown or inhibitor therapy on ERb agonist response in established and patient-derived OCa cells. Mechanistic studies were conducted using RNA-seq, discovery proteomics, chromatin immunoprecipitation (ChIP), co-immunoprecipitation (co-IP), proximity ligation, ERE-Luc reporter, RT-qPCR, and western blot analysis. The efficacy of the combination of KDM1A inhibitor and ERb agonist therapy was investigated using patient-derived explant (PDeX) models. In vivo efficacy of KDM1A inhibitor and ERb agonist was determined using orthotopic OCa and patient-derived xenograft (PDX) murine models.

Results: Analysis of TCGA datasets revealed a negative correlation between ERb and KDM1A expression in OCa patients. ChIP experiments showed that KDM1A is enriched at the ERb 0N promoter and that KDM1A KD, KO, or inhibition specifically upregulates the expression of ERb isoform 1. Co-IP and proximity ligation assays demonstrated that KDM1A interacts with ERb. Combining the ERb agonist LY500307 with KDM1A inhibitor NCD38 decreased the cell viability, survival, and invasion of both established and patient-derived primary OCa cells while increasing apoptosis. KDM1A KD- or inhibition potentiated the efficacy of ERb agonist in inducing ERb target gene expression via altered histone methylation marks. RNA-seq and proteomic analysis demonstrated that KDM1A KO and ERb agonist treatment increased the expression of apoptotic genes and downregulated cell cycle, EMT, and DNA repair genes. Importantly, combination therapy significantly reduced OCa cell proliferation in PDeX models and reduced in vivo tumor growth in orthotopic and PDX models.

Conclusions: Our findings demonstrate that KDM1A inhibition enhances ERb expression and tumor suppressive functions, suggesting that combination therapy of a KDM1A inhibitor and ERb agonist may be a promising therapeutic option for treating OCa.

Citation Format: Prabhakar P. Venkata, Sridharan Jayamohan, Yi He, Salvador Alejo, Jessica D. Johnson, Uday P. Pratap, Suryavathi Viswanadhapalli, Susan Weintraub, Rajeshwar R. Tekmal, Ratna K. Vadlamudi, Edward Kost, Gangadhara R. Sareddy. KDM1A/LSD1 inhibition enhances estrogen receptor beta mediated tumor suppression in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3081.

Abstract 4813: ERX-208 as a novel therapeutic for treating ovarian cancer by enhancing endoplasmic reticulum stress

Background: Ovarian cancer (OCa) is the deadliest of all gynecologic cancers in the United States. Despite initial response to chemotherapy, most OCa patients become chemo resistant and progress to metastatic disease. Here, we tested the hypothesis that the high basal level of endoplasmic reticulum stress (ERS) in OCa represents a critical vulnerability and drugs that further aggravate this already engaged system in OCa may exhaust its protective features and contribute to apoptosis induction. The objective of this proposal is to identify a hit compound that enhances ERS in OCa and to conduct mechanistic studies.

Methods: We synthesized a small library of >200 chemically distinct oligobenzamide analogs with maintenance of the chemical backbone but altered R groups of ERX-11. We performed the primary screening of this library to evaluate the induction of mRNA levels of two canonical ERS/UPR (unfolded protein response) genes- sXBP1 and CHOP. Biological activity of ERX-208 was validated using multiple OCa cells. Mechanistic studies were conducted using CRISPR/Cas9 KO, Western blotting, reporter gene assays, IHC and RNA-seq analysis. PK (pharmacokinetics) and toxicity studies were done using C57BL/6 mice. Cell line-derived xenografts (CDXs), patient-derived xenografts (PDXs), patient-derived explants (PDEs), and patient-derived organoids (PDO) were used for preclinical evaluation.

Results: From a screen of a curated ERX-11 derived oligobenzamide library, we identified a hit compound, ERX-208 that potently (IC50~100nM) induces ERS/UPR and apoptosis in multiple OCa cells in vitro. CRISPR KO screen identified the lysosomal acid lipase A (LIPA) protein as the critical target of ERX-208. LIPA KO abrogates response to ERX-208, while reconstitution of LIPA restores ERX-208 response. The time course studies showed a robust and consistent induction (>15-fold CHOP, and >10-fold sXBP1) by ERX-208 treatment within 24h. We confirmed induction of classic UPR components peIF2α, CHOP and LC3B using Western blotting in multiple OCa cells. Functionally, ERX-208 causes growth inhibition of OCa cells, as noted by MTT cell viability assays using 15 OCa cells with an IC50 of ~50-100nM. The activity of ERX-208 is distinct among oligobenzamides as ERX-11 has limited/no activity against OCa cells. RNA-seq analysis confirmed that ERX-208 induces significant ERS, UPR, and apoptosis. Further, ERX-208 reduced the growth of OCa PDO’s in vitro, PDEs ex vivo and CDXs and PDXs in vivo. ERX-208 treatment did not show any signs of toxicity and body weight of mice was not affected. IHC analyses showed increased activation of ERS/UPR markers such as GRP78, p-PERK and decreased proliferation measured by Ki67.

Conclusions: Collectively, our results demonstrated the utility of ERX-208 and will establish a novel therapeutic paradigm in OCa that overcomes tumor heterogeneity by targeting LIPA and enhancing ERS leading to apoptosis.

Citation Format: Suryavathi Viswanadhapalli, Tae-Kyung Lee, Kara Kassees, Gaurav Sharma, Rahul Gopalam, Karla Parra, Tanner Reese, Michael Hsieh, Uday P. Pratap, Xue Yang, Behnam Ebrahimi, Chia Yuan Chen, Scott Terry Elmore, Christian Cervantes, Zhenming Xu, Edward Kost, Gangadhara Reddy Sareddy, Rajeshwar Rao Tekmal, Jung-Mo Ann, Ganesh V. Raj, Ratna K. Vadlamudi. ERX-208 as a novel therapeutic for treating ovarian cancer by enhancing endoplasmic reticulum stress. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4813.

Abstract 891: Therapeutic targeting of ovarian cancer stem cells using estrogen receptor beta agonist

Background: Ovarian cancer (OCa) is the deadliest gynecologic cancer. Emerging studies suggest that ovarian cancer stem cells (OCSCs) contribute to tumor relapse and chemotherapy resistance. Recent studies demonstrate that OCa cells express estrogen receptor beta (ERβ), which functions as a tumor suppressor. However, the status of ERβ expression in OCSCs and the therapeutic utility of ERβ agonist LY500307 for targeting OCSCs remain unknown. In this study, we tested the hypothesis that OCSCs express ERβ and that treatment with ERβ agonist reduces stemness and promotes apoptosis of OCSCs.

Methods: We isolated subpopulations of OCSCs from SKOV3, A2780, and patient-derived ascites cells using ALDEFLUOR kit and examined the expression of ERβ in OCSCs using RT-qPCR. The effect of ERβ agonist LY500307 on OCSCs was examined utilizing cell viability, cell cycle, sphere formation, self-renewal, and apoptosis assays. Mechanistic studies were conducted using RNA-seq, RT-qPCR, and Western blot analysis. The efficacy of LY500307 on the tumor-initiating capacity of OCSCs was determined via in vivo limiting dilution assay studies using orthotopic intrabursal xenograft murine models.

Results: RT-qPCR assay showed that ERβ, particularly ERβ isoform 1, is highly expressed in OCSCs compared to non-OCSCs. ERβ agonist LY500307 significantly reduced the viability of OCSCs compared to non-OCSCs. Treatment of OCSCs with LY500307 significantly reduced the sphere formation and self-renewal of OCSCs. Further, LY500307 treatment resulted in G2/M cell cycle arrest and promoted the apoptosis of OCSCs. Mechanistic studies using RNA-seq analysis demonstrated that ERβ agonist treatment resulted in the modulation of pathways related to cell cycle and apoptosis. Western blots and RT-qPCR assays confirmed the upregulation of genes involved in apoptosis and cell cycle arrest, such as FDXR and CDKN1A. Importantly, treatment of LY500307 significantly attenuated the tumor-initiating capacity of OCSCs in orthotopically implanted OCa murine models.

Conclusions: Our results demonstrate that ERβ agonist LY500307 is highly efficacious in reducing the stemness and promoting apoptosis of OCSCs and may serve as a novel therapeutic agent in treating OCa

Citation Format: Yi He, Salvador Alejo, Prabhakar P. Venkata, Jessica D. Johnson, Ilanna Loeffel, Julie Ann Martel, Uday P. Pratap, Suryavathi Viswanadhapalli, Rajeshwar R. Tekmal, Ratna K. Vadlamudi, Edward Kost, Gangadhara R. Sareddy. Therapeutic targeting of ovarian cancer stem cells using estrogen receptor beta agonist [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 891.

Abstract P5-10-01: Leukemia inhibitory factor receptor inhibition reduces obesity driven progression of triple negative breast cancer

Background: The obesity epidemic is rapidly increasing in the USA and obese women are at a higher likelihood of developing triple negative breast cancer (TNBC). Several studies implicated the importance of the breast microenvironment on the aggressive cancer biology especially obese microenvironment. However, the underlying mechanism(s) by which obesity contributes to the progression of TNBC remains unclear. The objective of this study is to test a novel concept that obesity upregulates leukemia inhibitory factor receptor (LIFR) oncogenic signaling in TNBC and test whether LIFR inhibition blocks TNBC progression. Methods: Established TNBC cell lines were co-cultured with human primary adipocytes or incubated with adipocyte conditioned medium or with high glucose (HG) followed by treatment with LIFR inhibitor EC359. The effect of adiposity on TNBC cells was determined using cell viability, colony formation, and invasion assays. Mechanistic studies were performed using CRISPR/Cas9 KO of LIFR, Western blotting, RT-qPCR, and reporter gene assays. Utility of LIFR inhibitor EC359 was tested using xenografts, and patient derived organoid (PDO) models. Results: Treatment of TNBC cells with adipose conditions or HG increased the proliferation and invasion of TNBC cells. Western blot and RT-qPCR analyses confirmed that increased expression of LIFR correlated with enhanced downstream LIFR signaling such as STAT3 and subsequent activation of STAT3 target genes. CRISPR KO of LIFR or treatment of TNBC cells with EC359 significantly reduced the cell viability, colony formation and invasion under adipose conditions. Western blotting results showed that co-culture with adipocytes significantly enhanced LIFR downstream signaling in TNBC model cells and is effectively blocked by LIFR KO or EC359 treatment. Further, EC359 treatment blocked the adipose environment mediated growth of organoids. Importantly, co-implantation of adipocytes significantly enhanced TNBC xenograft tumor growth, however treatment with EC359 significantly attenuated adipocyte induced TNBC progression. Conclusions: Collectively, these results suggest that adiposity contributes to increased TNBC cell growth via upregulation of the LIF/LIFR pathway. The LIF/LIFR axis represents a potential therapeutic target for adiposity driven TNBC and the LIFR inhibitor EC359 could be used as a new therapeutic agent to treat obesity associated TNBC.

Citation Format: Suryavathi Viswanadhapalli, Uday P Pratap, Behnam Ebrahimi, Logan Blankenship, Jaitri Joshi, Zexuan Liu, Kristin A Altwegg, Xiaonan Li, Gangadhara R Sareddy, Bindu Santhamma, Swapna Konda, Manjeet Rao, Edward Kost, Rajeshwar R Tekmal, Hareesh B Nair, Ratna K Vadlamudi. Leukemia inhibitory factor receptor inhibition reduces obesity driven progression of triple negative breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-10-01.

LIF/LIFR oncogenic signaling is a novel therapeutic target in endometrial cancer

Endometrial cancer (EC) is the fourth most common cancer in women. Advanced-stage EC has limited treatment options with a poor prognosis. There is an unmet need for the identification of actionable drivers for the development of targeted therapies in EC. Leukemia inhibitory factor receptor (LIFR) and its ligand LIF play a major role in cancer progression, metastasis, stemness, and therapy resistance. However, little is known about the functional significance of the LIF/LIFR axis in EC progression. In this study using endometrial tumor tissue arrays, we identified that expression of LIF, LIFR is upregulated in EC. Knockout of LIFR using CRISPR/Cas9 in two different EC cells resulted in a significant reduction of their cell viability and cell survival. In vivo studies demonstrated that LIFR-KO significantly reduced EC xenograft tumor growth. Treatment of established and primary patient-derived EC cells with a novel LIFR inhibitor, EC359 resulted in the reduction of cell viability with an IC50 in the range of 20-100 nM and induction of apoptosis. Further, treatment with EC359 reduced the spheroid formation of EC cancer stem cells and reduced the levels of cancer stem cell markers SOX2, OCT4, NANOG, and Axin2. Mechanistic studies demonstrated that EC359 treatment attenuated the activation of LIF-LIFR driven pathways, including STAT3 and AKT/mTOR signaling in EC cells. Importantly, EC359 treatment resulted in a significant reduction of the growth of EC patient-derived explants ex vivo, EC cell line-derived xenografts, and patient-derived xenografts in vivo. Collectively, our work revealed the oncogenic potential of the LIF/LIFR axis in EC and support the utility of LIFR inhibitor, EC359, as a novel targeted therapy for EC via the inhibition of LIF/LIFR oncogenic signaling.

Abstract 1253: Therapeutic targeting of endometrial cancer with novel LIFR inhibitor EC359

Background: Endometrial cancer (EC) is the fourth most common cancer in women. Approximately 80% of EC belong to the endometroid-EC subtype and are driven by estrogen signaling. Advanced-stage EC has limited treatment options with poor prognosis. There is an urgent need for the identification of actionable drivers as new targets for treating advance stage EC. Leukemia inhibitory factor receptor (LIFR) and its ligand LIF plays a major role in cancer progression, metastasis, stemness, and therapy resistance. Published and our preliminary data suggest a critical role of the LIF-LIFR signaling axis in EC progression. The objective of this study is to test the utility of targeting the LIF/LIFR axis using a novel LIFR inhibitor, EC359.

Methods: We used multiple established and primary EC cells to test the utility LIFR inhibitor, EC359 in treating EC. CRISPR/Cas9 system was used to generate LIFR KO EC cells. In vitro activity was tested using Cell-Titer Glo, MTT, invasion, and apoptosis assays. Mechanistic studies were conducted using Western blot, reporter gene assays, and RNA-seq analysis. EC cell-derived xenograft (CDX) and patient-derived explant (PDEX) models were used for preclinical evaluation and toxicity.

Results: EC359 treatment of seven EC cells showed anti-proliferative effects in MTT cell viability assays with an IC50 of 25-100 nM. Further, EC359 treatment reduced invasiveness, stemness, and promoted apoptosis of EC cells. The activity of EC359 is dependent on LIF/LIFR expression in EC cells. CRISPR mediated knockout of LIFR significantly abolished EC359 activity. In vivo xenograft studies using Ishikawa-vector or LIFR-KO cells demonstrated that LIFR-KO significantly reduced EC tumor growth, and tumor weights. Further, EC359 treatment attenuated the activation of LIF/LIFR driven pathways, including STAT3, AKT-mTOR signaling. Mechanistic studies using RNA-seq revealed that EC359 significantly upregulated 213 genes and down regulated 126 genes. Pathway analyses of differential genes revealed enrichment in the apoptotic pathways upon EC359 treatment. EC359 (5mg/kg body weight) treatment significantly reduced CDX tumor progression and reduced proliferation in PDEX models.

Conclusions: Collectively, these data support EC359 as a novel targeted therapy for EC by inhibiting LIF/LIFR oncogenic signaling pathway.

Citation Format: Weiwei Tang, Kumaraguruparan Ramasamy, Sureshkumar M. Pillai, Bindu Santhamma, Swapna Konda, Prabhakar P. Vekata, Logan Blankenship, Junhao Liu, Zexuan Liu, Kristin A. Altwegg, Behnam Ebrahimi, Uday P. Pratap, Xiaonan Li, Edward Kost, Gangadhara R. Sareddy, Ratna K. Vadlamudi, Hareesh B. Nair, Rajeshwar R. Tekmal, Suryavathi Viswanadhapalli. Therapeutic targeting of endometrial cancer with novel LIFR inhibitor EC359 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1253.

Pulmonary arterial venous malformations as primary manifestation of gestational trophoblastic neoplasia

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A unique initial presentation of GTN as pulmonary arteriovenous malformations.

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Metastatic GTN presenting as multiple visceral AVMs in the brain, liver, and lungs.

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Management of metastatic GTN with brain metastases with induction chemotherapy.

Abstract 4316: Targeting LIFR overcomes HDAC inhibitor resistance in ovarian cancer

Ovarian cancer (OCa) is the deadliest of all gynecologic cancers in the United States and a critical need exists for the development of novel therapies for the treatment of OCa. Leukemia inhibitory factor receptor (LIFR) and its ligand LIF play a critical role in cancer progression, metastasis, stem cell maintenance, and therapy resistance. Recent clinical studies showed that cancer cells elucidate feedback activation of LIFR that limits response to histone deacetylase (HDAC) inhibitors. Recently, we developed a first-in-class inhibitor of LIFR, EC359 that directly interacts with LIFR and effectively blocks LIF-LIFR interactions. Here, we examined whether LIFR inhibitor EC359 abrogate the side effects of histone deacetylase inhibitor SAHA (Vorinostat) for the treatment of OCa.

Methods: The effect of EC359 and SAHA as a combination therapy on OCa cell viability was examined by MTT assays. The efficacy of combination therapy on cell survival and apoptosis was determined using clonogenic assays and caspase3/7 assays respectively. The efficacy of combination therapy on OCa stem cells was determined using extreme limiting dilution assays. Mechanistic studies were performed using western blotting, qRT-PCR and Mass Spectrometry analyses. The effect of combination therapy on STAT3 signaling was examined using reporter gene assays. The in vivo efficacy of combination therapy on tumors was examined using ex vivopatient derived explants and mouse xenograft models.

Results: EC359 significantly enhanced the efficacy of SAHA in reducing cell viability, colony formation ability, and apoptosis compared to monotherapy of SAHA in multiple established and primary OCa cells. Further, EC359 enhanced SAHA ability to reduce self-renewal of OCa stem cells. As expected in STAT3 reporter assays, SAHA treatment activated STAT3 reporter and EC359 addition abrogated SAHA mediated STAT3 activation. Mechanistic studies using multiple OCa models and western blot analysis confirmed activation of LIFR signaling pathway upon SAHA treatment and its blockage by EC359 treatment. Treatment of human primary OCa tumor explants with EC359 enhanced ability of SAHA to decrease the proliferation (Ki-67 positivity) compared to monotherapy treated tumors. DIA based Mass Spectrometry analyses identified unique pathways modulated by combination therapy. Treatment of OCa xenografts with EC359 enhanced the ability of SAHA to reduce in vivotumor growth compared to monotherapy treated tumors.

Conclusions: Our results suggest that EC359 has therapeutic utility in overcoming the limitation of feedback activation of LIFR observed in the treatment of HDAC inhibitors in treating OCa.

Citation Format: Mengxing Li, Suryavathi Viswanadhapalli, Gangadhara Reddy Sareddy, Bindu Santhamma, Hui Yan, Zhenming Xu, Edward Kost, Rajeshwar Rao Tekmal, Hareesh B. Nair, Klaus J. Nickisch, Ratna K. Vadlamudi. Targeting LIFR overcomes HDAC inhibitor resistance in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4316.

Abstract 280: Synthetic lethality of KDM1A and mTOR inhibitors: A novel combination therapy for endometrial cancer

Background: Endometrial cancer (EC) is the sixth most common cancer in women. Annually 63,230 new cases are diagnosed with 11,350 deaths estimated in the USA. Currently, advanced EC therapies remain palliative and new therapeutic strategies are urgently needed. Common risk factors include exposure to high levels of estrogen, obesity, and alterations in genetic and epigenetic factors. The lysine-specific demethylase-1A (KDM1A/LSD1) regulates gene expression programs by changing the epigenetic histone marks at the gene promoters. Emerging studies provided the evidence that KDM1A is overexpressed in EC. In studies examining the synthetic lethality of KDM1A inhibition on chemotherapy drug sensitivity, we made an unexpected discovery that KDM1A inhibition potentiate activity of mTOR inhibitors. In this study, we tested the hypothesis that inhibition of KDM1A could sensitize EC to mTOR inhibitor therapy.

Methods: To study the significance of KDM1A inhibition on chemotherapy drug sensitivity, we performed MTT assays to screen 119 FDA approved drugs using KDM1A knockdown HEC1A and RL95 EC cell lines. Effect of KDM1A knockdown or KDM1A inhibitor (NCD-38) therapy on EC cells was examined using MTT cell viability assays and clonogenic survival assays. The effect on cell migration was examined using scratch wound healing assay. Mechanistic studies were conducted using RNA-seq, western blot, qRT-PCR, and IHC analysis. The in vivo efficacy of NCD-38 and sirolimus on EC progression was studied using mouse xenograft models.

Results: Studies using 119 FDA approved drugs identified that mTOR inhibitors sirolimus and temsirolimus has potent synthetic lethality on KDM1A knockdown cells compared to control cells. Cell viability and survival assays demonstrated that KDM1A knockdown or inhibition in combination with sirolimus synergistically reduced cell viability and the survival of EC cells. Further, combination of KDM1A inhibitor and sirolimus reduced the migration of EC cells. Western blot analysis demonstrated that knockdown or inhibition of KDM1A attenuated the activation of mTOR signaling cascade in EC cells. RNA-seq and gene set enrichment analysis identified the down regulation of E2F pathway and DNA replication pathways in KDM1A and mTOR inhibitor treated cells compared to control cells. Further, combination of NCD-38 and sirolimus significantly reduced the in vivo tumor progression in xenograft models. IHC analysis of tumors revealed the downregulation of proliferation marker Ki67 and phosphorylation of mTOR signaling molecules in combination treated tumors compared to vehicle treated tumors.

Conclusions: The results from these studies provide compelling evidence that KDM1A inhibition sensitizes EC cells to mTOR inhibitors, and the use of KDM1A inhibitor in conjunction with mTOR inhibitors may be an attractive therapy for advanced EC patients.

Citation Format: Prabhakar Pitta-Venkata, Bridgitte Palacios, Yihong Chen, Suryavathi Viswanadhapalli, Uday P. Pratap, Yiliao Luo, Mengxing Li, Kristin Altwegg, Xiaonan Li, Takayoshi Suzuki, Rajeshwar Rao Tekmal, Edward Kost, Gangadhara Reddy Sareddy. Synthetic lethality of KDM1A and mTOR inhibitors: A novel combination therapy for endometrial cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 280.

Abstract 5150: Adipose-derived stem cell disruption of gap junction intercellular communication in obesity-associated endometrial cancer

Endometrial cancer is the most common gynecologic cancer. It is divided into two major types, a less aggressive endometrioid type and a more aggressive serous type. Recent clinical observations underscore obesity as a major risk factor for endometrial cancer. In this study, we hypothesized that obesity can result in long term epigenetic modifications in the endometrial compartment, leading to the promotion of endometrial cancer. We examined the role of adipose-derived stem cells (ASCs), which are adipocyte progenitors, in the endometrial tumor microenvironment. By staining for ASCs in a tumor tissue microarray, we observed ASC infiltration that was specific to samples from obese patients, correlating with body mass index (R2=0.77, p<0.001). Using a co-culture system to simulate ASC microenvironmental effects and transcriptomic analysis, we showed that exposure of immortalized endometrial epithelial cells (EECs) to ASC secreted factors led to the repression of cell-cell communication pathways, most notably gap junctions and related factors tight junction proteins TJP and PKC genes. This gene repression was associated with induction of DNA Methylation in the promoter of the major GJ gene GJA1 (encoding connexin 43, Cx43) in the ASC-exposed EECs. Importantly, we further demonstrated this DNA hypermethylation in the promoters of the GJA1, TJP2 and PKC genes in primary endometrial tumors from obese patients compared to non-obese patients. We assessed the effects of epigenetic regulation on gap junction intercellular communication (GJIC) and cell-cell interactions using cellular calcein dye transfer assays and atomic force microscopy (for nano-scale assessment of cell-cell adhesion) by treating endometrial cancer cells with a demethylating agent (DAC). DAC treatment resulted in increased level of cell-cell adhesiveness and communication via gap junction coupling. Specific reactivation of GJA1 (Cx43) by expression vector in endometrial cancer cells led to decreased cellular motility. Because we found that PAI-1 is a major adipokine in the ASC secretome, inhibition of PAI-1 in ASC-exposed EECs led to a cell population expression profile with lower GJ expression, based on single-cell PCR studies. Collectively, the data demonstrate multi-scale regulation of cellular communication via paracrine actions and direct cell-cell coupling via gap junctions by epigenetic silencing influenced by ASCs. This leads to disruption of cellular homeostasis and enhanced motility, promoting endometrial cancer in obese patients.

Citation Format: Li-Ling Lin, Srikanth Polusani, Guangcun Huang, Chun-Lin Lin, Chiou-Miin Wang, Nicholas Lucio, Mikhail Kolonin, Alexes Daquinag, Pawel Osmulski, Bruce Nicholson, Edward Kost, Tim Huang, Nameer B. Kirma. Adipose-derived stem cell disruption of gap junction intercellular communication in obesity-associated endometrial cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5150.

Vulvar cancer in human immunodeficiency virus-seropositive premenopausal women: a case series and review of the literature

This review describes three cases of human immunodeficiency virus-infected women who were diagnosed with vulvar cancer before age 40 years. A retrospective chart review was performed for three patients who were younger than 40 years of age and who had histologically confirmed invasive squamous cell carcinoma of the vulva diagnosed between 1999 and 2002. Demographic, clinical, and laboratory data were recorded. Three human immunodeficiency virus-seropositive women were diagnosed with invasive squamous cell carcinoma of the vulva, stages IA, IB1, and III. All cases were characterized by extensive surrounding vulvar, vaginal, and cervical intraepithelial neoplasia. CD4 cell counts were 250, 330, and 900 cells/uL. Two patients experienced previous acquired immune deficiency syndrome-defining illnesses: toxoplasmosis and cervical cancer. Vulvar cancer in young human immunodeficiency virus-seropositive women may be associated with other human papillomavirus-related diseases and immunosuppression, as evidenced by low CD4 counts and the presence of antecedent acquired immune deficiency syndrome-defining illnesses.

Cancer among first-degree relatives of probands with invasive and borderline ovarian cancer

OBJECTIVE

The familial clustering of ovarian, breast, endometrial, colon; and prostate cancer was compared in first-degree relatives of probands with invasive and borderline ovarian cancer to determine coaggregation.

METHODS

Probands (n=392), who had been patients in the Division of Gynecologic Oncology at Washington University, were ascertained consecutively. Family history on 2192 first-degree relatives was collected by personal interviews of the probands and other family members. Estimates of prevalence of cancers in first-degree relatives of the two proband groups were compared. Survival analysis was used to examine the age-at-onset distribution of each cancer in relatives of invasive probands versus relatives of borderline probands.

RESULTS

Among the relatives were 24 cases of ovarian cancer, 46 cases of breast cancer, 13 cases of endometrial cancer, and 25 and 28 cases of colon and prostate cancer, respectively. There were no significant differences in the prevalence of any of these cancers in relatives of the invasive and borderline probands. Cumulative lifetime risk estimates did not differ between the relatives of the two groups for any cancers. Age-at-onset of ovarian cancer did not differ between probands with positive family histories of the five cancers and those with negative histories. The inability to reject the null hypothesis of no differences in the first-degree relatives of our two study groups might be from insufficient power to detect small differences, given our sample size.

CONCLUSION

These results suggest that relatives of patients with invasive and borderline ovarian cancer might share similar cancer risks and age-at-onset distributions.