Hematogenous Metastasis of Ovarian Cancer: Rethinking Mode of Spread

SummaryOvarian cancer has a clear predilection for metastasis to the omentum, but the underlying mechanisms involved in ovarian cancer spread are not well understood. Here, we used a parabiosis model that demonstrates preferential hematogenous metastasis of ovarian cancer to the omentum. Our studies revealed that the ErbB3-neuregulin 1 (NRG1) axis is a dominant pathway responsible for hematogenous omental metastasis. Elevated levels of ErbB3 in ovarian cancer cells and NRG1 in the omentum allowed for tumor cell localization and growth in the omentum. Depletion of ErbB3 in ovarian cancer impaired omental metastasis. Our results highlight hematogenous metastasis as an important mode of ovarian cancer metastasis. These findings have implications for designing alternative strategies aimed at preventing and treating ovarian cancer metastasis

B Cells as an Immune-Regulatory Signature in Ovarian Cancer

Increasing evidence suggests that the immune system plays a dynamic role in the progression of ovarian cancer, the deadliest gynecological malignancy worldwide. Accumulation of tumor-infiltrating lymphocytes has been associated with increased survival in ovarian cancer patients, and diverse interactions among immune cells in the tumor microenvironment determine tumor progression. While the regulatory functions of T cells among tumor-infiltrating lymphocytes are well defined and also involve therapeutic interventions, the role of B cells in ovarian cancer progression is still limited to their impact on survival. Recent studies have identified both pro- and anti-tumor responses of B cells in solid tumors, as different subsets of B cells play diverse roles in progression. Thus, in-depth characterization of B cell subtypes in each disease stage is crucial for understanding the importance and therapeutic potential of these cells in ovarian cancer. In this review, we summarize current knowledge about B cells in ovarian cancer and discuss emerging therapeutic interventions that could harness B cells to combat this deadly disease

Emerging Role of Extracellular Vesicles in Immune Regulation and Cancer Progression

The development of effective therapies for cancer treatment requires a better understanding of the tumor extracellular environment and a dynamic interaction between tumor cells, the cells of the immune system, and the tumor stroma. Increasing evidence suggests that extracellular vesicles play an important role in this interaction. Extracellular vesicles are nanometer-sized membrane-bound vesicles secreted by various types of cells that facilitate intracellular communication by transferring proteins, various lipids, and nucleic acids, especially miRNAs, between cells. Extracellular vesicles play discrete roles in the immune regulatory functions, such as antigen presentation, and activation or suppression of immune cells. Achieving therapeutic intervention through targeting of extracellular vesicles is a crucial area of research now. Thus, a deeper knowledge of exosome biology and the molecular mechanism of immune regulation is likely to provide significant insight into therapeutic intervention utilizing extracellular vesicles to combat this dreadful disease. This review describes the recent updates on immune regulation by extracellular vesicles in cancer progression and possible use in cancer therapy

Metabolic Reprogramming in Tumor-Associated Macrophages in the Ovarian Tumor Microenvironment

The interaction between tumor cells and macrophages in the tumor microenvironment plays an essential role in metabolic changes in macrophages and reprograms them towards a pro-tumorigenic phenotype. Increasing evidence indicates that macrophage metabolism is a highly complex process and may not be as simple as previously thought. Pro-inflammatory stimuli switch macrophages towards an M1-like phenotype and rely mainly on aerobic glycolysis and fatty acid synthesis, whereas anti-inflammatory stimuli switch macrophages towards an M2-like phenotype. M2-like macrophages depend more on oxidative phosphorylation (OXPHOS) and fatty acid oxidation. However, this metabolically reprogrammed phenotypic switch in macrophages remained a mystery for a while. Therefore, through this review, we tend to describe how macrophage immunometabolism determines macrophage phenotypes and functions in tumor microenvironments (TMEs). Furthermore, we have discussed how metabolic reprogramming in TAM can be used for therapeutic intervention and drug resistance in ovarian cancer

Combining epitope-distinct antibodies to HER2: cooperative inhibitory effects on invasive growth.

International audienceMonoclonal antibodies (mAbs) to HER2 are currently used to treat breast cancer, but low clinical efficacy, along with primary and acquired resistance to therapy, commonly limit clinical applications. We previously reported that combinations of antibodies directed at non-overlapping epitopes of HER2 are endowed with enhanced antitumor effects, probably due to accelerated receptor degradation. Here, we extend these observations to three-dimensional mammary cell models, and compare the effects of single mAbs with the effects of antibody combinations. Collectively, our in vitro assays and computational image analyses indicate that combining mAbs against different epitopes of HER2 better inhibits invasive growth. Importantly, while growth factors are able to reduce intraluminal apoptosis and induce an invasive phenotype, combinations of mAbs better than single mAbs can reverse the growth factor-induced phenotypes of HER2-overexpressing spheroids. In conclusion, our studies propose that mAb combinations negate the biological effects of growth factors on invasive growth of HER2-overexpressing cells. Hence, combining mAbs offers a therapeutic strategy, potentially able to enhance clinical efficacy of existing antireceptor immunotherapeutics

Preclinical activity of selinexor in combination with eribulin in uterine leiomyosarcoma

Abstract Leiomyosarcoma (LMS) is a rare soft tissue sarcoma (STS) that begins in smooth muscle tissue and most often initiates in the abdomen or uterus. Compared with other uterine cancers, uterine LMS (ULMS) is an aggressive tumor with poor prognosis and a high risk of recurrence and death, regardless of the stage at presentation. Selinexor is a first-in-class selective inhibitor of nuclear export (SINE) compound that reversibly binds to exportin 1 (XPO1), thereby reactivating tumor suppressor proteins and downregulating the expression of oncogenes and DNA damage repair (DDR) proteins. In this study, we evaluated the effects of selinexor in combination with doxorubicin and eribulin in the LMS tumor model in vitro and in vivo. Treatment of selinexor combined with eribulin showed synergistic effects on tumor growth inhibition in SK-UT1 LMS-derived xenografts. Immunohistochemical assessment of the tumor tissues showed a significantly reduced expression of proliferation (Ki67) and XPO1 markers following combination therapy compared to the control group. Global transcriptome analyses on tumor tissue revealed that the combination therapy regulates genes from several key cancer-related pathways that are differentially expressed in ULMS tumors. To our knowledge, this is the first preclinical study demonstrating the anti-cancer therapeutic potential of using a combination of selinexor and eribulin in vivo. Results from this study further warrant clinical testing a combination of chemotherapy agents with selinexor to reduce the morbidity and mortality from ULMS

Patient-Derived Ovarian Cancer Spheroids Rely on PI3K-AKT Signaling Addiction for Cancer Stemness and Chemoresistance

Ovarian cancer is the most lethal gynecological malignancy among women worldwide and is characterized by aggressiveness, cancer stemness, and frequent relapse due to resistance to platinum-based therapy. Ovarian cancer cells metastasize through ascites fluid as 3D spheroids which are more resistant to apoptosis and chemotherapeutic agents. However, the precise mechanism as an oncogenic addiction that makes 3D spheroids resistant to apoptosis and chemotherapeutic agents is not understood. To study the signaling addiction mechanism that occurs during cancer progression in patients, we developed an endometrioid subtype ovarian cancer cell line named ‘MCW-OV-SL-3’ from the ovary of a 70-year-old patient with stage 1A endometrioid adenocarcinoma of the ovary. We found that the cell line MCW-OV-SL-3 exhibits interstitial duplication of 1q (q21–q42), where this duplication resulted in high expression of the PIK3C2B gene and aberrant activation of PI3K-AKT-ERK signaling. Using short tandem repeat (STR) analysis, we demonstrated that the cell line exhibits a unique genetic identity compared to existing ovarian cancer cell lines. Notably, the MCW-OV-SL-3 cell line was able to form 3D spheroids spontaneously, which is an inherent property of tumor cells when plated on cell culture dishes. Importantly, the tumor spheroids derived from the MCW-OV-SL-3 cell line expressed high levels of c-Kit, PROM1, ZEB1, SNAI, VIM, and Twist1 compared to 2D monolayer cells. We also observed that the hyperactivation of ERK and PI3K/AKT signaling in these cancer cells resulted in resistance to cisplatin. In summary, the MCW-OV-SL3 endometrioid cell line is an excellent model to study the mechanism of cancer stemness and chemoresistance in endometrioid ovarian cancer

Direct Upregulation of STAT3 by MicroRNA-551b-3p Deregulates Growth and Metastasis of Ovarian Cancer

Summary: 3q26.2 amplification in high-grade serous ovarian cancer leads to increased expression of mature microRNA miR551b-3p, which is associated with poor clinical outcome. Importantly, miR551b-3p contributes to resistance to apoptosis and increased survival and proliferation of cancer cells in vitro and in vivo. miR551b-3p upregulates STAT3 protein levels, and STAT3 is required for the effects of miR551b-3p on cell proliferation. Rather than decreasing levels of target mRNA as expected, we demonstrate that miR551b-3p binds a complementary sequence on the STAT3 promoter, recruiting RNA polymerase II and the TWIST1 transcription factor to activate STAT3 transcription, and thus directly upregulates STAT3 expression. Furthermore, anti-miR551b reduced STAT3 expression in ovarian cancer cells in vitro and in vivo and reduced ovarian cancer growth in vivo. Together, our data demonstrate a role for miR551b-3p in transcriptional activation. Thus, miR551b-3p represents a promising candidate biomarker and therapeutic target in ovarian cancer. : Chaluvally-Raghavan et al. find that miR551b-3p affects transcription of STAT3. The authors find that miR551b-3p binds to the STAT3 promoter and facilitates RNA polymerase II and TWIST1 transcription factor recruitment, which in turn activates STAT3 transcription