Epithelial-to-Mesenchymal Transition Supports Ovarian Carcinosarcoma Tumorigenesis and Confers Sensitivity to Microtubule Targeting with Eribulin

Molecular characteristics of tubo-ovarian carcinosarcoma at different anatomic locations

Carcinosarcoma (CS) is an uncommon and clinically aggressive malignancy. The objective of the present study was to characterize the molecular features of CS at various anatomic locations, including serous effusions. Specimens (n = 32) consisted of 25 biopsies/surgical resection specimens and 7 serous effusions (6 peritoneal, 1 pleural) from 25 patients. Fresh-frozen cell pellets and surgical specimens underwent targeted next-generation sequencing covering 50 unique genes. A total of 31 mutations were found in 25 of the 32 tumors studied, of which 1 had 3 mutations, 4 had 2 different mutations, and 20 had a single mutation. The most common mutations were in TP53 (n = 25 in 24 tumors; 1 tumor with 2 different mutations), with less common mutations found in RB1 (n = 2), MET (n = 1), KRAS (n = 1), PTEN (n = 1), and KIT (n = 1). Patient-matched specimens harbored the same TP53 mutation. Tumors with no detected mutations were more common in serous effusion specimens (3/7; 43%) compared with surgical specimens (4/25; 16%). In conclusion, the molecular landscape of CS is dominated by TP53 mutations, reinforcing the observation that the majority of these tumors develop from high-grade serous carcinoma. Whether CS cells in serous effusions differ from their counterparts in solid lesions remains uncertain.

Teratoma combined with struma ovarii and sarcomatoid carcinoma: a case report and review of the literature

This is a rare case of struma ovarii combined with sarcomatoid carcinoma. Because struma ovarii and ovarian sarcomatoid carcinoma have an extremely low incidence, this may be the first case of a combined occurrence of both. Therefore, this report describes its clinical manifestations, diagnosis, and treatment, analyzes the pathogenesis, and summarizes the previous literature in the hope that it can be helpful to other tumor-related medical personnel and provide material support for the formation of guidelines for this disease.

CHK1 inhibitor SRA737 is active in PARP inhibitor resistant and CCNE1 amplified ovarian cancer

High-grade serous ovarian cancers (HGSOCs) with homologous recombination deficiency (HRD) are initially responsive to poly (ADP-ribose) polymerase inhibitors (PARPi), but resistance ultimately emerges. HGSOC with CCNE1 amplification (CCNE1 amp) are associated with resistance to PARPi and platinum treatments. High replication stress in HRD and CCNE1 amp HGSOC leads to increased reliance on checkpoint kinase 1 (CHK1), a key regulator of cell cycle progression and the replication stress response. Here, we investigated the anti-tumor activity of the potent, highly selective, orally bioavailable CHK1 inhibitor (CHK1i), SRA737, in both acquired PARPi-resistant BRCA1/2 mutant and CCNE1 amp HGSOC models. We demonstrated that SRA737 increased replication stress and induced subsequent cell death in vitro. SRA737 monotherapy in vivo prolonged survival in CCNE1 amp models, suggesting a potential biomarker for CHK1i therapy. Combination SRA737 and PARPi therapy increased tumor regression in both PARPi-resistant and CCNE1 amp patient-derived xenograft models, warranting further study in these HGSOC subgroups.

A Novel Method for the Early Detection of Single Circulating, Metastatic and Self-Seeding Cancer Cells in Orthotopic Breast Cancer Mouse Models

BACKGROUND

Metastasis is the main cause of cancer-related deaths, but efficient targeted therapies against metastasis are still missing. Major gaps exist in our understanding of the metastatic cascade, as existing methods cannot combine sensitivity, robustness, and practicality to dissect cancer progression. Addressing this issue requires improved strategies to distinguish early metastatic colonization from metastatic outgrowth.

METHODS

Luciferase-labelled MDA-MB-231, MCF7, and 4T1 breast cancer cells were spiked into samples from tumour-naïve mice to establish the limit of detection for disseminated tumour cells. Luciferase-labelled breast cancer cells (±unlabelled cancer-associated fibroblasts; CAFs) were orthotopically implanted in immunocompromised mice. An ex vivo luciferase assay was used to quantify tumour cell dissemination.

RESULTS

In vitro luciferase assay confirmed a linear and positive correlation between cancer cell numbers and the bioluminescence detected at single cell level in blood, brain, lung, liver, and mammary fat pad samples. Remarkably, single luciferase-labelled cancer cells were detectable in all of these sites, as the bioluminescence quantified in the analysed samples was substantially higher than background levels. Ex vivo, circulating tumour cells, metastasis, and tumour self-seeding were detected in all samples from animals implanted with highly metastatic luciferase-labelled MDA-MB-231 cells. In turn, detection of poorly metastatic luciferase-labelled MCF7 cells was scarce but significantly enhanced upon co-implantation with CAFs as early as 20 days after the experiment was initiated.

CONCLUSIONS

These results demonstrate the feasibility of using an ultrasensitive luciferase-based method to dissect the mechanisms of early metastatic colonization to improving the development of antimetastatic therapies.

Ovarian carcinosarcoma is highly aggressive compared to other ovarian cancer histotypes

Background

Ovarian carcinosarcoma (OCS) is an unusual ovarian cancer type characterized by distinct carcinomatous and sarcomatous components. OCS has been excluded from many of the pan-histotype studies of ovarian carcinoma, limiting our understanding of its behavior.

Methods

We performed a multi-cohort cross-sectional study of characteristics and outcomes in ovarian cancer patients from Scotland (n=2082) and the Surveillance, Epidemiology and End Results Program (SEER, n=44946) diagnosed with OCS or one of the other major histotypes: high grade serous (HGSOC), endometrioid (EnOC), clear cell (CCOC), mucinous (MOC) or low grade serous ovarian carcinoma (LGSOC). Differences in overall survival were quantified using Cox regression models to calculate hazard ratios (HR).

Results

Across both cohorts, OCS patients were significantly older at diagnosis compared to all other histotypes (median age at diagnosis 69 and 67 in Scottish and SEER cohorts) and demonstrated the shortest survival time upon univariable analysis. Within the Scottish cohort, 59.3% and 16.9% of OCS patients presented with FIGO stage III and IV disease, respectively; this was significantly higher than in EnOC, CCOC or MOC (P<0.0001 for all), but lower than in HGSOC (P=0.004). Multivariable analysis accounting for other prognostic factors identified OCS as independently associated with significantly shorter survival time compared to HGSOC, EnOC, LGSOC and MOC in both the Scottish (multivariable HR vs OCS: HGSOC 0.45, EnOC 0.39, LGSOC 0.26, MOC 0.43) and SEER cohorts (multivariable HR vs OCS: HGSOC 0.59, EnOC 0.34, LGSOC 0.30, MOC 0.81). Within the SEER cohort, OCS also demonstrated shorter survival compared to CCOC (multivariable HR 0.63, 95% CI 0.58-0.68), but this was not replicated within the Scottish cohort (multivariable HR for CCOC: 1.05, 95% CI 0.74-1.51). Within early-stage disease specifically (FIGO I-II or SEER localized stage), OCS was associated with the poorest survival of all histotypes across both cohorts. In the context of late-stage disease (FIGO III-IV or SEER distant stage), OCS, MOC and CCOC represented the histotypes with poorest survival.

Conclusion

OCS is a unique ovarian cancer type that affects older women and is associated with exceptionally poor outcome, even when diagnosed at earlier stage. New therapeutic options are urgently required to improve outcomes.

A risk-reward examination of sample multiplexing reagents for single cell RNA-Seq

Single-cell RNA sequencing (scRNA-Seq) has emerged as a powerful tool for understanding cellular heterogeneity and function. However the choice of sample multiplexing reagents can impact data quality and experimental outcomes. In this study, we compared various multiplexing reagents, including MULTI-Seq, Hashtag antibody, and CellPlex, across diverse sample types such as human peripheral blood mononuclear cells (PBMCs), mouse embryonic brain and patient-derived xenografts (PDXs). We found that all multiplexing reagents worked well in cell types robust to ex vivo manipulation but suffered from signal-to-noise issues in more delicate sample types. We compared multiple demultiplexing algorithms which differed in performance depending on data quality. We find that minor improvements to laboratory workflows such as titration and rapid processing are critical to optimal performance. We also compared the performance of fixed scRNA-Seq kits and highlight the advantages of the Parse Biosciences kit for fragile samples. Highly multiplexed scRNA-Seq experiments require more sequencing resources, therefore we evaluated CRISPR-based destruction of non-informative genes to enhance sequencing value. Our comprehensive analysis provides insights into the selection of appropriate sample multiplexing reagents and protocols for scRNA-Seq experiments, facilitating more accurate and cost-effective studies.

Compartment-specific multiomic profiling identifies SRC and GNAS as candidate drivers of epithelial-to-mesenchymal transition in ovarian carcinosarcoma

BACKGROUND

Ovarian carcinosarcoma (OCS) is an exceptionally aggressive and understudied ovarian cancer type harbouring distinct carcinomatous and sarcomatous compartments. Here, we seek to identify shared and compartment-specific events that may represent potential therapeutic targets and candidate drivers of sarcomatous compartment formation through epithelial-to-mesenchymal transition (EMT).

METHODS

We performed multiomic profiling (exome sequencing, RNA-sequencing, microRNA profiling) of paired carcinomatous and sarcomatous components in 12 OCS cases.

RESULTS

While paired sarcomatous and carcinomatous compartments demonstrate substantial genomic similarities, multiple loci are recurrently copy number-altered between components; regions containing GNAS and SRC are recurrently gained within the sarcomatous compartment. CCNE1 gain is a common event in OCS, occurring more frequently than in high grade serous ovarian carcinoma (HGSOC). Transcriptomic analysis suggests increased MAPK activity and subtype switching toward poor prognosis HGSOC-derived transcriptomic subtypes within the sarcomatous component. The two compartments show global differences in microRNA profiles, with differentially expressed microRNAs targeting EMT-related genes (SIRT1, ZEB2) and regulators of pro-tumourigenic pathways (TGFβ, NOTCH); chrX is a highly enriched target of these microRNAs and is also frequently deleted across samples. The sarcomatous component harbours significantly fewer CD8-positive cells, suggesting poorer immune engagement.

CONCLUSION

CCNE1 gain and chrX loss are frequent in OCS. SRC gain, increased GNAS expression and microRNA dysregulation represent potential mechanisms driving sarcomatous compartment formation.

Spotlight on Carcinosarcoma of the Ovary: A Scoping Review

Ovarian carcinosarcoma, also referred as malignant mixed Mullerian tumour, is an uncommon, highly aggressive and malignant neoplasm which makes up 1 to 4% of all ovarian tumours. It is biphasic involving both malignant sarcomatous (mesenchymal) and carcinomatous (epithelial) cells. There are various subtypes such as serous and endometrioid. However, the mesenchymal part is sarcomatous. About 90% of cases of ovarian carcinosarcoma spread outside the ovary. The two most accepted theories of origin for carcinosarcoma of the ovary are the collision and conversion theories. A third theory is the combination theory. Prognosis remains poor even when still localised in the ovary. In the last few years, there has been no change in the survival rate. The median survival rate is lower than 2 years. Clinical features mainly include lower abdominal pain and a palpable abdominal mass. Ovarian carcinosarcoma remains poorly understood and understudied. Being a rare tumour, elaborate therapeutic consensus is not available for ovarian carcinosarcoma. The main treatment involves cytoreductive surgery and then chemotherapy. The type of chemotherapy, role of radiotherapy and novel therapies need to be further studied. The main objective of this article is to review the current literature on carcinosarcoma of the ovary.

The microtubule inhibitor eribulin demonstrates efficacy in platinum-resistant and refractory high-grade serous ovarian cancer patient-derived xenograft models

Background

Despite initial response to platinum-based chemotherapy and PARP inhibitor therapy (PARPi), nearly all recurrent high-grade serous ovarian cancer (HGSC) will acquire lethal drug resistance; indeed, ~15% of individuals have de novo platinum-refractory disease.

Objectives

To determine the potential of anti-microtubule agent (AMA) therapy (paclitaxel, vinorelbine and eribulin) in platinum-resistant or refractory (PRR) HGSC by assessing response in patient-derived xenograft (PDX) models of HGSC.

Design and methods

Of 13 PRR HGSC PDX, six were primary PRR, derived from chemotherapy-naïve samples (one was BRCA2 mutant) and seven were from samples obtained following chemotherapy treatment in the clinic (five were mutant for either BRCA1 or BRCA2 (BRCA1/2), four with prior PARPi exposure), recapitulating the population of individuals with aggressive treatment-resistant HGSC in the clinic. Molecular analyses and in vivo treatment studies were undertaken.

Results

Seven out of thirteen PRR PDX (54%) were sensitive to treatment with the AMA, eribulin (time to progressive disease (PD) ⩾100 days from the start of treatment) and 11 out of 13 PDX (85%) derived significant benefit from eribulin [time to harvest (TTH) for each PDX with p < 0.002]. In 5 out of 10 platinum-refractory HGSC PDX (50%) and one out of three platinum-resistant PDX (33%), eribulin was more efficacious than was cisplatin, with longer time to PD and significantly extended TTH (each PDX p < 0.02). Furthermore, four of these models were extremely sensitive to all three AMA tested, maintaining response until the end of the experiment (120d post-treatment start). Despite harbouring secondary BRCA2 mutations, two BRCA2-mutant PDX models derived from heavily pre-treated individuals were sensitive to AMA. PRR HGSC PDX models showing greater sensitivity to AMA had high proliferative indices and oncogene expression. Two PDX models, both with prior chemotherapy and/or PARPi exposure, were refractory to all AMA, one of which harboured the SLC25A40-ABCB1 fusion, known to upregulate drug efflux via MDR1.

Conclusion

The efficacy observed for eribulin in PRR HGSC PDX was similar to that observed for paclitaxel, which transformed ovarian cancer clinical practice. Eribulin is therefore worthy of further consideration in clinical trials, particularly in ovarian carcinoma with early failure of carboplatin/paclitaxel chemotherapy.

IGJ suppresses breast cancer growth and metastasis by inhibiting EMT via the NF‑κB signaling pathway

Breast cancer metastasis is the primary cause of mortality of patients with breast cancer. The present study aimed to explore the role and underlying mechanisms of IGJ in the invasion and metastasis of breast cancer. The Cancer Genome Atlas database was utilized to analyze the differential gene expression profiles in patients with breast cancer with or without metastasis; the target gene, joining chain of multimeric IgA and IgM (JCHAIN, also known as IGJ, as referred to herein), with significant expression and with prognostic value was screened. The expression levels of IGJ in human breast cancer paired tissues and cell lines were detected using reverse transcription‑quantitative PCR and western blot analysis. IGJ differential expression was detected in paired human breast cancer tissues using immunohistochemistry. The role of IGJ in breast cancer was verified using CCK‑8, invasion and migration assays, and scratch tests in vivo and in vitro. Further exploration of the role and mechanism of IGJ in breast cancer was conducted through Gene Set Enrichment Analysis, Kyoto Encyclopedia of Genes and Genomes analysis, western blot analysis and immunofluorescence experiments. Through the analysis of gene expression profiles, it was found that IGJ was poorly expressed in patients with breast cancer with metastasis compared to patients with non‑metastatic breast cancer. The overexpression of IGJ was associated with an improved distant metastasis‑free survival and overall survival (OS). COX multivariate regression analysis demonstrated that IGJ was an independent prognostic factor for the OS and relapse‑free survival of patients with breast cancer. In comparison to healthy breast cancer adjacent tissues and cell lines, IGJ was poorly expressed in breast cancer tissues and cell lines (P<0.05). Further analyses indicated that the overexpression of IGJ suppressed the proliferation, invasion and metastasis of breast cancer cells in vivo and in vitro by inhibiting the occurrence of epithelial‑to‑mesenchymal transition (EMT) and suppressing the nuclear translocation of p65. Finally, rescue experiments indicated that IGJ restricted the proliferation and metastasis of breast cancer cells by regulating the NF‑κB signaling pathway. On the whole, the present study demonstrates that IGJ suppresses the invasion and metastasis of breast cancer by inhibiting both the occurrence of EMT and the NF‑κB signaling pathway. These findings may provide novel biomarkers and potential therapeutic targets for the treatment of metastatic breast cancer.

Folate receptor alpha is widely expressed and a potential therapeutic target in uterine and ovarian carcinosarcoma

OBJECTIVE

Folate receptor alpha (FRα), which is expressed in various cancers, is a potential therapeutic target. However, its expression and clinical significance in uterine (UCS) and ovarian carcinosarcoma (OCS) remain to be elucidated.

METHODS

This retrospective study included patients with gynecologic carcinosarcoma who underwent primary surgery between 1997 and 2019 at our institution. Immunohistochemical staining of surgical FFPE specimens was performed for FRα and HER2. FRα was evaluated using the H-score and the 4-tired scoring system (0 to 3+). Subsequently, FRα expression (≥5% of tumor cells with ≥1+ intensity) and FRα-high (score 2+ and 3+) were evaluated. HER2 was scored according to the modified ASCO/CAP criteria. The association between FRα-high and clinicopathological features, HER2 expression, and survival was assessed in UCS.

RESULTS

A total of 120 patients with UCS and nine patients with OCS were included. In UCS, FRα expression was observed in all patients, whereas FRα-high status was present in 20% of patients. Among HER2-negative UCS, 34% exhibited FRα-high. No significant association was observed between clinicopathological characteristics and FRα status. During the follow-up period (median 34.5 mo), FRα-high was not strongly associated with progression, free survival, and overall survival. All the OCS tumor specimens showed FRα-high expression.

CONCLUSIONS

FRα expression was observed in all the UCS and OCS specimens, including HER2-negative UCS patients. This widespread FRα expression suggests that FRα-targeted therapies may hold promise for the treatment for gynecologic carcinosarcoma. However, in uterine carcinosarcoma, no significant relationship was observed between FRα expression and clinicopathological features or prognosis.

Interferon-ε is a tumour suppressor and restricts ovarian cancer

High-grade serous ovarian cancers have low survival rates because of their late presentation with extensive peritoneal metastases and frequent chemoresistance1, and require new treatments guided by novel insights into pathogenesis. Here we describe the intrinsic tumour-suppressive activities of interferon-ε (IFNε). IFNε is constitutively expressed in epithelial cells of the fallopian tube, the cell of origin of high-grade serous ovarian cancers, and is then lost during development of these tumours. We characterize its anti-tumour activity in several preclinical models: ovarian cancer patient-derived xenografts, orthotopic and disseminated syngeneic models, and tumour cell lines with or without mutations in Trp53 and Brca genes. We use manipulation of the IFNε receptor IFNAR1 in different cell compartments, differential exposure status to IFNε and global measures of IFN signalling to show that the mechanism of the anti-tumour activity of IFNε involves direct action on tumour cells and, crucially, activation of anti-tumour immunity. IFNε activated anti-tumour T and natural killer cells and prevented the accumulation and activation of myeloid-derived suppressor cells and regulatory T cells. Thus, we demonstrate that IFNε is an intrinsic tumour suppressor in the female reproductive tract whose activities in models of established and advanced ovarian cancer, distinct from other type I IFNs, are compelling indications of potential new therapeutic approaches for ovarian cancer.