Abstract 3860: Drug resistance-mediating collagens (drmCOLs) are themselves druggable by an FDA/EMA-approved medicine to cause cancer cell arrest and apoptosis: Proof-of-conceptin vitro

Purpose of study: Tumor-generated collagen types I and III, identified two decades ago as factors of progression-free interval and survival in ovarian cancer (https://pubmed.ncbi.nlm.nih.gov/12468338/), mediate chemotherapeutic resistance, as do types VI and XI (https://pubmed.ncbi.nlm.nih.gov/34645978/, Table S1). All occur in pan-cancer gene signatures (https://pubmed.ncbi.nlm.nih.gov/27609069/). Collagens require Pro/Lys hydroxylation by 2-oxoacid utilizing dioxygenases (2OUDs) for native fold-dependent secretion and extracellular function; underhydroxylated collagens misfold and clog the endoplasmic reticulum. The HAG mechanism resolves 2OUD catalysis at orbital level, classifies all possible 2OUD inhibitors (https://pubmed.ncbi.nlm.nih.gov/6281585/), and is ‘seminal ‘ (https://pubmed.ncbi.nlm.nih.gov/7857312/) for development of collagen-suppressive drugs. We read the collagen-suppressive potential of the lifelong administered medicine deferiprone (DEF) off the HAG mechanism. Hypothesis: By blocking ligand reaction-driven ferryl formation in 2OUD catalysis, DEF at clinical range (10-150 µM) causes misfolded drmCOLs to trigger the unfolded protein response (UPR), effecting proliferative arrest and apoptosis preferentially of cancer cells.

Methods: Genetically defined cell line models for high grade serous ovarian cancer (KURAMOCHI), uterine serous cancer (ARK1), normal matrix (MRC5); metabolic labeling; RNA-seq; flow cytometry.

Results: In MRC5, DEF inhibited [3H]Pro/[3H]Lys hydroxylation, not incorporation. Cells expressed numerous COL mRNAs, e.g. 32 in ARK1 that suffice to generate 21 of 28 types of collagen; mRNAs for types I, VI, and XI/II predominated. Intracellular drmCOLs were confirmed by flow cytometry, using sequence-specific antibodies against COL1A1 (NBP1-77457AF700), COL3A1 (ab237239), COL6A1 (sc-377143), and COL11A2 (bs-2924R-A350). Within 48 hrs, DEF caused COL1A1/COL3A1/COL11A2 reactivity to increase up to 3-fold over controls; after 96 hrs, reactivity returned to control values in MRC5, remained elevated in KURAMOCHI, and rose further in ARK1, revealing cell-specific UPR set points. DEF at 48 hrs caused COL6A1 mRNA to decrease yet COL6A1 reactivity to increase in ARK1, evidencing the adaptive UPR ineffectively controls the accumulation of proteotoxic collagen. Activation of the ablative UPR, via enhanced DDIT3, XBP1, TRIB3, BAK1, PMAIP1, and HRK expression, coincided with a decline in cancer cell count by >80% within 96 hrs, an effect not observed in MRC5.

Conclusions: HAG mechanism-defined inhibitors of drmCOL hydroxylation, pioneered by DEF, activate cytoreductive UPR effects in cancer cells preferentially. DEF use lacks adverse UPR or matrix effects, encouraging a pilot trial and 2OUD inhibitor development for oncological indication.

Citation Format: Spencer M. Goering, Sukhwinder Singh, Bernadette M. Cracchiolo, Angela A. Sadev, Isabel W. Cracchiolo, Mainul Hoque, Axel-Rainer Hanauske, Yasmin Abedin, Hartmut Martin Hanauske-Abel. Drug resistance-mediating collagens (drmCOLs) are themselves druggable by an FDA/EMA-approved medicine to cause cancer cell arrest and apoptosis: Proof-of-conceptin vitro [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 3860.

Abstract 6074: Resistance to MK-0752 alters Notch activity and expression of stemness markers in uterine leiomyosarcoma cell lines

Introduction: Uterine leiomyosarcoma (uLMS) is a rare tumor with poor survival and few therapeutic options. The Notch pathway is evolutionarily conserved, is active in uterine processes, has oncogenic properties in many cancers, but has not been well studied in uLMS. Cancer stem cells (CSC) are subpopulations of cancer cells that are treatment resistant. In certain tumors, activation of canonical Notch signaling, via gamma secretase, supports CSC survival and the acquisition of chemoresistance. Our objective is to identify and characterize the subpopulation of uLMS cells that are viable after treatment with the half maximal inhibitory concentration (IC50) of MK-0752, a gamma secretase inhibitor (GSI) in phase I trials. We will determine Notch signaling activity and expression of markers associated with stem-like potential in GSI resistant uLMS cells.

Methods: MTT assays were performed on SK-LMS-1 and SK-UT-1B, two uLMS cell lines, to identify the IC50 for MK-0752. Cells were exposed to MK-0752 at the IC50 or DMSO (control) for 24 hours and viable cells were collected. First, expression of stemness markers, CD133, cMYC and SOX2, in uLMS cells was compared to human uterine smooth muscle cells (hUT-SMC) at baseline. After treatment with MK-0752, the remaining subpopulations of resistant uLMS cells were evaluated for Notch signaling activity by expression of HES1. Stemness marker expression was also assessed. Gene expression was measured with qRT-PCR. Mean fold change (FC) gene expression was determined by FC experimental divided by FC control, relative to expression of 18S rRNA. P≤0.05 was considered significant.

Results: In untreated uLMS cells, expression of CD133 and c-MYC was significantly higher in SK-LMS-1 (fibroblast morphology) vs hUT-SMC, while expression of CD133 and SOX2 was significantly higher in SK-UT-1B (epithelial morphology) vs hUT-SMC. After treatment with MK-0752 at IC50 (427.4 µM for SK-LMS-1 or 128.4µM for SK-UT-1B) expression of HES1 was decreased in SK-LMS-1 (0.35x, p≤0.05) and increased in SK-UT-1B (2.38x, p≤0.01) in treatment resistant, viable cells as compared to untreated cells. Expression of c-MYC was decreased (0.38x, p≤0.01) and CD133 was similar (1.64x, p>0.05) in GSI resistant SK-LMS-1 cells, while expression of CD133 and SOX2 was similar (1.43x and 1.30x, respectively, p>0.05) in GSI resistant SK-UT-1B cells compared to untreated cells.

Conclusions: Cellular morphology, Notch signaling activity and expression of stemness markers differs in GSI resistant SK-LMS-1 compared to GSI resistant SK-UT-1B cells. The subpopulation of MK-0752 resistant SK-LMS-1 cells have reduced Notch activity and reduced expression of stemness marker, c-MYC, while the resistant SK-UT-1B cells have increased Notch activity. Further studies are required to identify additional factors associated with uLMS resistance to GSIs and the importance of this heterogeneity of uLMS in vivo.

Citation Format: Yasmin Abedin, Emily Alpert, Erica Rego, Karla Larios, Emma Cheung, Sofia Gabrilovich, Qingshi Zhao, Mark H. Einstein, Nataki Douglas. Resistance to MK-0752 alters Notch activity and expression of stemness markers in uterine leiomyosarcoma cell lines [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 6074.

Gamma Secretase Inhibitors as Potential Therapeutic Targets for Notch Signaling in Uterine Leiomyosarcoma

Uterine leiomyosarcoma (uLMS) is a rare and aggressive cancer with few effective therapeutics. The Notch signaling pathway is evolutionarily conserved with oncogenic properties, but it has not been well studied in uLMS. The purpose of our study was to determine expression of Notch family genes and proteins and to investigate the therapeutic effect of γ-secretase inhibitors (GSIs), indirect inhibitors of Notch signaling, in uLMS. We determined expression of Notch genes and proteins in benign uterine smooth muscle tissue, fibroids, and uLMS samples by immunostaining and in two uLMS cell lines, SK-UT-1B (uterine primary) and SK-LMS-1 (vulvar metastasis) by RT-PCR, Western blot and immunostaining. We exposed our cell lines to GSIs, DAPT and MK-0752, and measured expression of HES1, a downstream effector of Notch. Notch proteins were differentially expressed in uLMS. Expression of NOTCH3 and NOTCH4 was higher in uLMS samples than in benign uterine smooth muscle and fibroids. Expression of NOTCH4 was higher in SK-LMS-1 compared to SK-UT-1B. Exposure of SK-UT-1B and SK-LMS-1 to DAPT and MK-0752 decreased expression of HES1 and decreased uLMS cell viability in a dose- and time-dependent manner that was unique to each GSI. Our findings suggest that GSIs are potential therapeutics for uLMS, albeit with limited efficacy.

Recurrent granulosa cell tumor of the retroperitoneum during the COVID-19 Pandemic

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Granulosa cell tumors (GCTs) are sex cord stromal tumors that normally arise from the ovaries.

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Primary extraovarian GCTs are uncommon, but primary retroperitoneal GCTs are even rarer.

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Management of extraovarian GCTs can include surgery, chemotherapy, and/or anti-hormone therapy.

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Delays in care during the COVID-19 Pandemic may have led to advanced disease or progression of disease for cancer patients.

Extraovarian granulosa cell tumors are rare with very few cases of isolated retroperitoneal granulosa cell tumors reported in the literature. Granulosa cell tumors are notorious for late recurrences and patients should have long term oncologic follow up. We describe a case of recurrent granulosa cell tumor of the retroperitoneum that originally presented as a renal mass, which has not been described before in the literature. Her management was delayed in part due to the COVID-19 Pandemic. Oncologists must be vigilant regarding the consequences of postponed care during this difficult time.

A Pilot Study of Human Papillomavirus Detection in Urine Using a Novel Nucleic Acid Amplification Test

INTRODUCTION

Human papillomavirus (HPV) testing is the standard-of-care for cervical cancer screening globally. Urine is a promising alternative to collecting a cervical specimen during a pelvic exam for HPV testing. There are no studies to date of HPV testing of urine using the Xpert HPV test.

METHODS

We conducted a pilot study of 40 women; 30 women undergoing colposcopy because of a previous abnormality and 10 undergoing routine screening, to evaluate HPV detection in urine by the Xpert HPV test on the GeneXpert platform. Xpert HPV testing of urine was done according to the manufacturer's instructions for testing cervical specimens. These results were compared to a reference of combined results of 2 research HPV genotyping tests conducted on cervical specimens and to repeat Xpert HPV testing of urine.

RESULTS

Analytic sensitivity and specificity of Xpert testing of urine for any high-risk HPV versus the cervical sample, categorized as HPV positive if at least 1 test was positive, were 64.3% (95% confidence interval [95%CI]  = 42.1-76.1%) and 100% (97.5%CI = 71.5-100%), respectively. Analytic sensitivity and specificity of Xpert testing of urine for any high-risk HPV versus the cervical sample, categorized as positive if both tests were positive, were 66.7% (95%CI = 44.7-84.4%) and 86.7% (95%CI = 59.5-98.3%), respectively. Kappa values for first vs. second and first vs. third testing of urine by Xpert were 0.89 (95%CI = 0.79-1.00) and 0.90 (95%CI = 0.81-1.00), respectively.

DISCUSSION

Given the call for global elimination of cervical cancer and widespread availability of GeneXpert, optimizing Xpert HPV testing of urine may be warranted.

Abstract 5218: Inhibition of γ-secretase decreases Notch signaling and cell migration in uterine carcinosarcoma

Carcinosarcoma (CS) is a rare and aggressive type II endometrial adenocarcinoma (EmCa) accounting for less than 5% of all uterine malignancies, but accounting for a disproportionately high disease-specific mortality rate. Notch signaling is an evolutionarily conserved pathway with oncogenic roles in several cancers. Notch proteins are expressed in Type I and Type II EmCa, cell lines, and human tissue, but Notch function has not been characterized in CS. To determine whether inhibiting Notch signaling may be a therapeutic target in CS we assessed expression of Notch family genes and the impact of γ-secretase inhibition on cellular migration in the CS cell line, CS-99, and compared to lower risk Type I EmCa cell line (HEC-1-A). Expression of Notch receptors, ligands and effectors was determined using RT-PCR. We determined the impact of exposure to DAPT, a γ-secretase inhibitor, vs DMSO (vehicle control) on cell viability with a MTT assay. The ability of DAPT to inhibit Notch signaling was assessed by quantitative (q) RT-PCR for the Notch effector, HES1. The relative expression level of each target gene was normalized to 18s rRNA. Cellular migration after exposure to DAPT was assessed using a scratch assay for CS-99 and HEC-1-A. The extent of cell migration was measured using ImageJ (NIH Bethesda, MD). CS-99 and HEC-1-A, expressed receptors NOTCH1-4, ligands DLL4, JAG1, JAG2, and effectors HES1, HEY1, and NRARP. The MTT assay revealed >88% cellular viability after 24 hr exposure to 10µM in CS-99 and 50µM DAPT in HEC-1-A. Exposure to DAPT significantly decreased expression HES1 in CS-99 and HEC-1-A. Migration was decreased in CS-99 and unchanged in HEC-1-A with 10µM and 50 µM of DAPT, respectively. Inhibition of Notch signaling activity decreased cellular migration in CS-99 cell line suggesting that Notch signaling may impact disease growth in CS. Unchanged HEC-1-A cellular migration suggests that Notch signaling might not impact disease growth in Type I EmCa. Inhibition of Notch signaling may be a promising therapeutic target in CS.

Inhibition of Notch signaling in CS-99 and HEC-1-A with a γ-secretase inhibitor (median + IQR)*HEC-1-A + DMSOHEC-1-A + DAPT 50μMP-valueCS-99 + DMSOCS-99 + DAPT 10μMP-valueHES1 (normalized fold change)0.94 (0.83-1.3)0.35 (0.25-0.41)0.0220.99 (0.84-1.2)0.19 (0.16-0.23)0.002% wound closure (0-6h)12.5 (8.5-15.5)24.1 (10.5-33.0)0.1311.4 (9.7-11.5)11.3 (9.1-11.4)0.7% wound closure (0-24h)38.1 (31.4-46.1)63.0 (33.6-100.0)0.2473.3 (66.6-73.9)61.7 (52.6-64.7)0.05

Citation Format: Sofia D. Gabrilovich, Yasmin Abedin, Sreevidya Santha, Tracy Wu, Mark Einstein, Nataki C. Douglas, Jenna Z. Marcus. Inhibition of γ-secretase decreases Notch signaling and cell migration in uterine carcinosarcoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5218.

Severe hypertriglyceridemia during treatment with intraperitoneal cisplatin and paclitaxel for advanced stage fallopian tube carcinoma

This case report describes a patient who developed severe hypertriglyceridemia (1871 mg/dL) and hyperlipidemia (LDL 132 mg/dL) during intraperitoneal (IP) administration of cisplatin and paclitaxel as adjuvant treatment for stage IIIC fallopian tube carcinoma. After an evaluation with her primary care physician, she was treated with gemfibrozil and rosuvastatin for the duration of her treatment. There was complete resolution of hypertriglyceridemia after completion of chemotherapy. This adverse event is rare and has not been reported in the literature with this chemotherapeutic regimen. A pre-chemotherapy evaluation for dyslipidemia may be beneficial in the detection and monitoring of this condition.

A Deceptive Spread: Myoinvasion of Endometrial Carcinoma Imitating Adenoma Malignum

Endometrioid type of endometrial carcinoma is the most common form of uterine malignancy. The majority of patients in the developed world present with the low-grade, low-stage type of this malignancy. The current treatment of early-stage endometrioid carcinoma provides most patients with a favorable outcome. One of the important factors that determine the outcome of early-stage endometrial carcinoma is the involvement of cervical stroma. One of the very rare forms of cervical stromal involvement by endometrioid carcinoma is termed "adenoma malignum type" invasion due to its similarity to the infamously deceptive type of cervical adenocarcinoma called adenoma malignum. Since adenoma malignum is often discovered incidentally, finding adenoma malignum type of myoinvasion may deceive a pathologist to diagnose the simultaneous presence of endometrial carcinoma and adenoma malignum in the same patient as 2 separate entities. Also, this type of myoinvasion may be missed altogether for its subtle nature. In this article, we report a case of low-grade, low-stage endometrioid carcinoma with adenoma malignum type of myoinvasion. We have pointed out the subtle nature of this lesion and the important features to remember to successfully identify it.