VEGFA activates an epigenetic pathway upregulating ovarian cancer-initiating cells

Polycomb Repressor Complex 1 (PRC1) in ovarian cancer: A scoping literature review

High grade serous carcinoma (HGSC) is the most common and the deadliest histologic subtype of epithelial ovarian cancer. HGSC is a therapeutic challenge, as it recurs in 80 % of patients diagnosed, often as chemoresistant disease. The mechanism of this chemoresistance is not fully elucidated, but it is partly attributed to the ability of HGSC to maintain a stem-like phenotype that enables development of resistance to current therapies. Polycomb Repressor Complexes 1 and 2 (PRC1/2) have been implicated in the maintenance of the stem cell compartment through silencing tumor suppressor genes and regulating stem cells. These complexes are comprised of multiple polycomb group (PcG) proteins that play a role in normal development, and when deregulated contribute to the development of cancer [2]. Proteins included in PRC1 include B lymphoma mouse Moloney leukemia virus insertion region (BMI1), RING1, and chromobox (CBX) proteins. We aimed to review each of the protein components of PRC1 and their mechanistic relationships to promoting chemoresistant recurrences and propagation of ovarian cancer. Where possible, we reviewed therapeutic investigations of these proteins. We utilized a scoping literature review through Covidence to identify 42 articles meeting criteria for inclusion. The authors identified four relevant articles and the Yale MeSH Analysis Grid Generator was used to establish additional keywords and heading terms. A medical librarian used these terms and articles to draft an initial search strategy within each of the following databases: MEDLINE, Embase, Cochrane Library, and Web of Science Core Collection, yielding 439 articles based on title and abstract. Abstracts were independently reviewed by the authors, identifying 77 articles for full text review, of which 35 were ultimately excluded, leaving 42 articles for full review. Our review identified the currently known mechanisms of the subunits of PRC1 that contribute to HGSC development, recurrence, and chemoresistance. By compiling a comprehensive review of available scientific knowledge, we support and direct further investigation into PRC1 that can affect meaningful advances in the treatment of HGSC.

The angiogenic role of the alpha 9-nicotinic acetylcholine receptor in triple-negative breast cancers

Nicotine acts as an angiogenic factor by stimulating endogenous cholinergic pathways. Several subtypes of nicotinic acetylcholine receptors (nAChRs) have been demonstrated to be closely correlated to the formation and progression of different types of cancers. Recently, several studies have found that nicotinic acetylcholine receptors α9 (α9-nAChRs) are highly expressed in breast tumors, especially in tumors derived from patients diagnosed at advanced stages. In vitro studies have demonstrated that activation of α9-nAChRs is associated with increased proliferation and migration of breast cancer. To study the tumor-promoting role of α9-nAChRs in breast cancers, we generated a novel anti-α9-nAChR and methoxy-polyethylene glycol (mPEG) bispecific antibody (α9 BsAb) for dissecting the molecular mechanism on α9-nAChR-mediated tumor progression. Unexpectedly, we discovered the angiogenic role of α9-nAChR in nicotine-induced neovascularization of tumors. It revealed α9 BsAbs reduced nicotine-induced endothelial cell tube formation, blood vessel development in Matrigel plug assay and angiogenesis in microtube array membrane murine model (MTAMs). To unbraid the molecular mechanism of α9-nAChR in nicotine-mediated angiogenesis, the α9 BsAbs were applied and revealed the inhibitory roles in nicotine-induced production of hypoxia-inducible factor-2 alpha (HIF-2α), vascular endothelial growth factor A (VEGF-A), phosphorylated vascular endothelial growth factor receptor 2 (p-VEGFR2), vascular endothelial growth factor receptor 2 (VEGFR2) and matrix metalloproteinase-9 (MMP9) from triple-negative breast cancer cells (MDA-MB-231), suggesting α9-nAChRs played an important role in nicotine-induced angiogenesis. To confirm our results, the shRNA targeting α9-nAChRs was designed and used to silence α9-nAChR expression and then evaluated the angiogenic role of α9-nAChRs. The results showed α9 shRNA also played an inhibitory effect in blocking the nicotine-induced angiogenic signaling. Taken together, α9-nAChR played a critical role in nicotine-induced angiogenesis and this bispecific antibody (α9 BsAb) may serve as a potential therapeutic candidate for treatments of the α9 positive cancers.

Integrated analysis of spatial transcriptomics and CT phenotypes for unveiling the novel molecular characteristics of recurrent and non-recurrent high-grade serous ovarian cancer

BACKGROUND

High-grade serous ovarian cancer (HGSOC), which is known for its heterogeneity, high recurrence rate, and metastasis, is often diagnosed after being dispersed in several sites, with about 80% of patients experiencing recurrence. Despite a better understanding of its metastatic nature, the survival rates of patients with HGSOC remain poor.

METHODS

Our study utilized spatial transcriptomics (ST) to interpret the tumor microenvironment and computed tomography (CT) to examine spatial characteristics in eight patients with HGSOC divided into recurrent (R) and challenging-to-collect non-recurrent (NR) groups.

RESULTS

By integrating ST data with public single-cell RNA sequencing data, bulk RNA sequencing data, and CT data, we identified specific cell population enrichments and differentially expressed genes that correlate with CT phenotypes. Importantly, we elucidated that tumor necrosis factor-α signaling via NF-κB, oxidative phosphorylation, G2/M checkpoint, E2F targets, and MYC targets served as an indicator of recurrence (poor prognostic markers), and these pathways were significantly enriched in both the R group and certain CT phenotypes. In addition, we identified numerous prognostic markers indicative of nonrecurrence (good prognostic markers). Downregulated expression of PTGDS was linked to a higher number of seeding sites (≥ 3) in both internal HGSOC samples and public HGSOC TCIA and TCGA samples. Additionally, lower PTGDS expression in the tumor and stromal regions was observed in the R group than in the NR group based on our ST data. Chemotaxis-related markers (CXCL14 and NTN4) and markers associated with immune modulation (DAPL1 and RNASE1) were also found to be good prognostic markers in our ST and radiogenomics analyses.

CONCLUSIONS

This study demonstrates the potential of radiogenomics, combining CT and ST, for identifying diagnostic and therapeutic targets for HGSOC, marking a step towards personalized medicine.

Semi-synthesized anticancer theobromine derivatives targeting VEGFR-2: in silico and in vitro evaluations

Vascular endothelial cell proliferation and angiogenesis are all crucially impacted by Endothelial Growth Factor Receptor-2 (VEGFR-2). Its expression is significantly boosted throughout pathologic angiogenesis causing the development of tumors. Sothat, inhibition of VEGFR-2 has crucial role in cancer treatment. In this study, novel semisynthetic theobromine derivatives were rationally designed as VEGFR-2 inhibitors and subjected to in vitro testing for their ability to block VEGFR-2 activation. Furthermore, the antiproliferative effects of these derivatives were evaluated. Compound 7 g exhibited the most potent anti-VEGFR-2 activity, with an IC50 value of 0.072 µM, and demonstrated excellent dose-dependent inhibitory activity against both MCF-7 and HepG2 cancer cells with IC50 values of 19.35 and 27.89 µM, respectively. Notably, compound 7 g exhibited high selectivity indices of 2.6 and 1.8 against MCF-7 and HepG2 cells, respectively. Compound 7 g induced G2/M phase cell cycle arrest, promoted apoptosis, and boosted immunomodulation by downregulating TNF-α expression and upregulating IL-2 levels in MCF-7 cells. The molecular docking analysis revealed that compound 7 g could bind effectively to the active site of VEGFR-2, and molecular dynamic simulations confirmed the stability of the VEGFR-2/compound 7 g complex. Furthermore, ADME and toxicity profiling indicated the potential suitability of these compounds as drug candidates. In summary, compound 7 g hold promise as a VEGFR-2 inhibitor.Communicated by Ramaswamy H. Sarma.

DNA Methyltransferase 3A: A Significant Target for the Discovery of Inhibitors as Potent Anticancer Drugs

DNA methyltransferase (DNMT) is a conserved family of Cytosine methylases, which plays a crucial role in the regulation of Epigenetics. They have been considered promising therapeutic targets for cancer. Among the DNMT family, mutations in the DNMT3A subtype are particularly important in hematologic malignancies. The development of specific DNMT3A subtype inhibitors to validate the therapeutic potential of DNMT3A in certain diseases is a significant task. In this review, we summarized the small molecule inhibitors of DNMT3A discovered in recent years and their inhibitory activities, and classified them based on their inhibitory mechanisms.

Design, synthesis, and antitumor screening of new thiazole, thiazolopyrimidine, and thiazolotriazine derivatives as potent inhibitors of VEGFR-2

New thiazole, thiazolopyrimidine, and thiazolotriazine derivatives 3-12 and 14a-f were synthesized. The newly synthesized analogs were tested for in vitro antitumor activity against HepG2, HCT-116, MCF-7, HeP-2, and Hela cancer cells. Results indicated that compound 5 displayed the highest potency toward the tested cancer cells. Compound 11b possessed enhanced effectiveness over MCF-7, HepG2, HCT-116, and Hela cancer cells. In addition, compounds 4 and 6 showed promising activity toward HCT-116, MCF-7, and Hela cancer cells and eminent activity against HepG2 and HeP-2 cells. Moreover, compounds 3-6 and 11b were tested for their capability to inhibit vascular endothelial growth factor receptor-2 (VEGFR-2) activity. The obtained results showed that compound 5 displayed significant inhibitory activity against VEGFR-2 (half-maximal inhibitory concentration [IC50 ] = 0.044 μM) comparable to sunitinib (IC50  = 0.100 μM). Also, the synthesized compounds 3-6 and 11b were subjected to in vitro cytotoxicity tests over WI38 and WISH normal cells. It was found that the five tested compounds displayed significantly lower cytotoxicity than doxorubicin toward normal cell lines. Cell cycle analysis proved that compound 5 induces cell cycle arrest in the S phase for HCT-116 and Hela cancer cell lines and in the G2/M phase for the MCF-7 cancer cell line. Moreover, compound 5 induced cancer cell death through apoptosis accompanied by a high ratio of BAX/BCL-2 in the screened cancer cells. Furthermore, docking results revealed that compound 5 showed the essential interaction bonds with VEGFR-2, which agreed with in vitro enzyme assay results. In silico studies showed that most of the analyzed compounds complied with the requirements of good oral bioavailability with minimal toxicity threats in humans.

Exploring the mechanism of resistance to vincristine in breast cancer cells using transcriptome sequencing technology

Breast cancer has replaced lung cancer as the leading cancer globally, but various chemotherapy drugs for breast cancer are prone to resistance, especially in patients with distant metastases who are susceptible to multiple chemotherapy drug resistance often leading to treatment failure. Vincristine (VCR) is an alkaloid extracted from Catharanthus roseus, and is often used in combination with other chemotherapy drugs to treat various types of cancer, including breast cancer. Research on the development of resistance to VCR has been carried out using transcriptome sequencing technology. Firstly, gradient increase of VCR concentration was used to produce a VCR-resistant breast cancer cell line. Mechanistically, RNA was extracted from the VCR-resistant breast cancer cell line, and the transcriptome was sequenced. Further analysis showed changes in the expression levels of various genes in the aforementioned VCR-resistant breast cancer cell line. Meanwhile, the analysis of splicing events also indicated a change in variable splicing events. Further validation showed that the expression levels of multiple genes, including interleukin-1β, were altered in the VCR-resistant breast cancer cell line, and these gene expression changes were related to VCR resistance. The results of the present study provide a theoretical basis for exploring the mechanism of VCR resistance clinically.

From seeds to survival rates: investigating Linum usitatissimum's potential against ovarian cancer through network pharmacology

Ovarian cancer is a malignant tumor that primarily forms in the ovaries. It often goes undetected until it has spread to the pelvis and abdomen, making it more challenging to treat and often fatal. Historically, natural products and their structural analogues have played a pivotal role in pharmacotherapy, especially for cancer. Numerous studies have demonstrated the therapeutic potential of Linum usitatissimum against ovarian cancer, but the specific molecular mechanisms remain elusive. This study combines data mining, network pharmacology, and molecular docking analysis to pioneer an innovative approach for ovarian cancer treatment by identifying potent phytochemicals. Findings of current study revealed that Apigenin, Vitamin E, Palmitic acid, Riboflavin, Isolariciresinol, 5-Dehydro-avenasterol, Cholesterol, Pantothenic acid, Nicotinic acid, Campesterol, Beta-Sitosterol, Stigmasterol, Daucosterol, and Vitexin suppress tumor growth by influencing AKT1, JUN, EGFR, and VEGFA. Kaplan-Meier survival analysis spotlighted AKT1, JUN, EGFR, and VEGFA as potential diagnostic and prognostic biomarkers for ovarian cancer. However, it is imperative to conduct in vivo and in vitro examinations to ascertain the pharmacokinetics and biosafety profiles, bolstering the candidacy of L. usitatissimum in ovarian cancer therapeutics.

Preclinical study of pachyman inducing ferroptosis against ovarian cancer: Biological targets and underlying mechanisms

Ferroptosis has gained extreme purpose in targeting cancer treatment. Poria cocos Wolf, a traditional Chinese herb, has potential anticancer properties, but the action and mechanism against ovarian cancer remain undetailed. Pachyman (Poria cocos polysaccharides) refers to the pharmacologically bioactive ingredients rich in Poria cocos. This study aimed to identify the potent actions and the network mechanisms of pachyman against ovarian cancer through preclinical analysis. Online-accessible database or platform was employed to predict candidate genes and core targets associated with ferroptosis in pachyman against ovarian cancer. Enrichment analyses were used to characterize the functional action and signaling mechanism in pachyman to treat ovarian cancer. Molecular docking imitation was conducted for verification of core target proteins. Network analysis uncovered that there were 30 mutual and 13 core genes targeting ferroptosis in pachyman and/against ovarian cancer, and additional enrichment analysis characterized that these core genes may act synergistically through multiple biological processes and molecular pathways associated with ferroptosis, including anti-inflammatory action, immunoregulation, and microenvironment modulation. The strongest affinities in core target proteins between pachyman and sarcoma (SRC), signal transducer, and activator of transcription 3 (STAT3) were further validated using molecular docking method. In conclusion, pachyman may induce antiovarian cancer potentials via regulating ferroptosis-associated biological functions and pharmacological mechanisms based on current bioinformatics findings. We reason that pachyman, the beneficial nutraceuticals, may be used clinically for future application in ovarian cancer treatment.

Inhibition of VEGFR2 and EGFR signaling cooperatively suppresses the proliferation of oral squamous cell carcinoma

BACKGROUND

Epidermal growth factor receptor (EGFR) is frequently overexpressed in oral squamous cell carcinoma (OSCC), and EGFR-targeting therapeutics have been widely employed to treat patients with a variety of carcinomas including OSCC. Here, we aimed to investigate alternative signaling for OSCC survival under the disruption of EGFR signaling.

METHODS

OSCC cell lines, namely HSC-3 and SAS, were utilized to investigate how EGFR disruption affects cell proliferation. Gene set enrichment analysis was performed to examine how EGFR disruption affects oncogenic signaling in OSCC cells. Disruption of KDR gene was performed using CRISPR/Cas9 techniques. A VEGFR inhibitor, vatalanib was used to research the impact of VEGFR inhibition on OSCC survival.

RESULTS

EGFR disruption significantly decreased the proliferation and oncogenic signaling including Myc and PI3K-Akt, in OSCC cells. Chemical library screening assays revealed that VEGFR inhibitors continued to inhibit the proliferation of EGFR-deficient OSCC cells. In addition, CRISPR-mediated disruption of KDR/VEGFR2 retarded OSCC cell proliferation. Furthermore, combined erlotinib-vatalanib treatment exhibited a more potent anti-proliferative effect on OSCC cells, compared to either monotherapy. The combined therapy effectively suppressed the phosphorylation levels of Akt but not p44/42.

CONCLUSION

VEGFR-mediated signaling would be an alternative signaling pathway for the survival of OSCC cells under the disruption of EGFR signaling. These results highlight the clinical application of VEGFR inhibitors in the development of multi-molecular-targeted therapeutics against OSCC.

"DEPHENCE" system-a novel regimen of therapy that is urgently needed in the high-grade serous ovarian cancer-a focus on anti-cancer stem cell and anti-tumor microenvironment targeted therapies

Ovarian cancer, especially high-grade serous type, is the most lethal gynecological malignancy. The lack of screening programs and the scarcity of symptomatology result in the late diagnosis in about 75% of affected women. Despite very demanding and aggressive surgical treatment, multiple-line chemotherapy regimens and both approved and clinically tested targeted therapies, the overall survival of patients is still unsatisfactory and disappointing. Research studies have recently brought some more understanding of the molecular diversity of the ovarian cancer, its unique intraperitoneal biology, the role of cancer stem cells, and the complexity of tumor microenvironment. There is a growing body of evidence that individualization of the treatment adjusted to the molecular and biochemical signature of the tumor as well as to the medical status of the patient should replace or supplement the foregoing therapy. In this review, we have proposed the principles of the novel regimen of the therapy that we called the "DEPHENCE" system, and we have extensively discussed the results of the studies focused on the ovarian cancer stem cells, other components of cancer metastatic niche, and, finally, clinical trials targeting these two environments. Through this, we have tried to present the evolving landscape of treatment options and put flesh on the experimental approach to attack the high-grade serous ovarian cancer multidirectionally, corresponding to the "DEPHENCE" system postulates.

LncRNA-UCA1 regulates lung adenocarcinoma progression through competitive binding to miR-383

The present study aimed to assess the role of the long non-coding RNA-urothelial cancer associated 1 (lncRNA-UCA1)/microRNA (miR)-383/vascular endothelial growth factor A (VEGFA) axis in regulating lung adenocarcinoma physiology through in vivo and in vitro experiments. The expression profile of lncRNA-UCA1 was analyzed by genome-wide analysis from GSE146459. The cell counting Kit-8, colony formation, wound healing and transwell assays were performed to evaluate the effects of lncRNA-UCA1 in vitro. In addition, luciferase reporter assays were performed to confirm the binding site. The expression levels of miR-383 and VEGFA in tumor cells were measured using reverse transcription-quantitative PCR. HCC-78 was also transfected with miR-383 mimics, inhibitors and siRNA-VEGFA before their viability was also assessed. Xenograft models were established in nude mice to investigate the tumor characteristics in vivo. The expression of lncRNA-UCA1 was significantly increased in tumor tissues and cells compared with adjacent tissues or HBE cells. Silencing lncRNA-UCA1 expression in cells resulted in a reduction in lung cancer cell viability. In addition, lncRNA-UCA1 silencing increased the expression of miR-383. Inhibiting miR-383 expression increased HCC-78 proliferation, migration and invasion, whilst reducing their apoptosis. miR-383 was shown to specifically target VEGFA to inhibit its expression at both the protein and mRNA levels. VEGFA knockdown resulted in a reduction in all aforementioned aspects of HCC-78 cell activity. In addition, inhibiting miR-383 expression led to larger tumor sizes in vivo. To conclude, the results of the study suggest that lncRNA-UCA1 can regulate the expression of miR-383 and, in turn, VEGFA.

Bioinformatics and In silico approaches to identify novel biomarkers and key pathways for cancers that are linked to the progression of female infertility: A comprehensive approach for drug discovery

Despite modern treatment, infertility remains one of the most common gynecologic diseases causing severe health effects worldwide. The clinical and epidemiological data have shown that several cancerous risk factors are strongly linked to Female Infertility (FI) development, but the exact causes remain unknown. Understanding how these risk factors affect FI-affected cell pathways might pave the door for the discovery of critical signaling pathways and hub proteins that may be targeted for therapeutic intervention. To deal with this, we have used a bioinformatics pipeline to build a transcriptome study of FI with four carcinogenic risk factors: Endometrial Cancer (EC), Ovarian Cancer (OC), Cervical Cancer (CC), and Thyroid Cancer (TC). We identified FI sharing 97, 211, 87 and 33 differentially expressed genes (DEGs) with EC, OC, CC, and TC, respectively. We have built gene-disease association networks from the identified genes based on the multilayer network and neighbour-based benchmarking. Identified TNF signalling pathways, ovarian infertility genes, cholesterol metabolic process, and cellular response to cytokine stimulus were significant molecular and GO pathways, both of which improved our understanding the fundamental molecular mechanisms of cancers associated with FI progression. For therapeutic intervention, we have targeted the two most significant hub proteins VEGFA and PIK3R1, out of ten proteins based on Maximal Clique Centrality (MCC) value of cytoscape and literature analysis for molecular docking with 27 phytoestrogenic compounds. Among them, sesamin, galangin and coumestrol showed the highest binding affinity for VEGFA and PIK3R1 proteins together with favourable ADMET properties. We recommended that our identified pathway, hub proteins and phytocompounds may be served as new targets and therapeutic interventions for accurate diagnosis and treatment of multiple diseases.

Advances in Stigmasterol on its anti-tumor effect and mechanism of action

Stigmasterol is a phytosterol derived from multiple herbaceous plants such as herbs, soybean and tobacco, and it has received much attention for its various pharmacological effects including anti-inflammation, anti-diabetes, anti-oxidization, and lowering blood cholesterol. Multiple studies have revealed that stigmasterol holds promise as a potentially beneficial therapeutic agent for malignant tumors because of its significant anti-tumor bioactivity. It is reported that stigmasterol has anti-tumor effect in a variety of malignancies (e.g., breast, lung, liver and ovarian cancers) by promoting apoptosis, inhibiting proliferation, metastasis and invasion, and inducing autophagy in tumor cells. Mechanistic study shows that stigmasterol triggers apoptosis in tumor cells by regulating the PI3K/Akt signaling pathway and the generation of mitochondrial reactive oxygen species, while its anti-proliferative activity is mainly dependent on its modulatory effect on cyclin proteins and cyclin-dependent kinase (CDK). There have been multiple mechanisms underlying the anti-tumor effect of stigmasterol, which make stigmasterol promising as a new anti-tumor agent and provide insights into research on its anti-tumor role. Presently, stigmasterol has been poorly understood, and there is a paucity of systemic review on the mechanism underlying its anti-tumor effect. The current study attempts to conduct a literature review on stigmasterol for its anti-tumor effect to provide reference for researchers and clinical workers.

Homo and Heterotypic Cellular Cross-Talk in Epithelial Ovarian Cancer Impart Pro-Tumorigenic Properties through Differential Activation of the Notch3 Pathway

An active fluidic microenvironment governs peritoneal metastasis in epithelial ovarian cancer (EOC), but its critical functional/molecular cues are not fully understood. Utilizing co-culture models of NIH3T3 cells (differentially overexpressing Jagged1) and SKOV3 cells expressing a Notch3 luciferase reporter-sensor (SNFT), we showed that incremental expression of Jagged1 led to proportional Notch3 activation in SNFT. With no basal luciferase activity, this system efficiently recorded dose-dependent Notch3 activation by rh-Jag1 peptide and the non-appearance of such induction in co-culture with NIH3T3Δjag1 cells indicates its sensitivity and specificity. Similar Notch3 modulation was shown for the first time in co-cultures with HGSOC patients' ascites-derived cancer-associated fibroblasts and Jagged1-expressing EOC cell lines. NIH3T3J1-A and OVCAR3 co-cultured SNFT cells showed maximum proliferation, invasion, and cisplatin resistance among all the heterotypic/homotypic cellular partners. VEGFA and CDKN1A are the two most upregulated genes identified across co-cultures by the gene profiler array. Co-culture induced VEGFA secretion from SNFT cells which also reduced cancer stem cell differentiation in platinum-resistant A2780 cells. rh-Jag1-peptide promoted enhanced nuclear-cytoplasmic p21 expression. Additionally, metastatic HGSOC tumors had higher VEGFA than corresponding primary tumors. This study thus demonstrates the tumoral and non-tumoral cell-mediated differential Notch3 activation imparting its tumorigenic effects through two critical molecular regulators, VEGFA and p21, during EOC progression.

DOT1L Is a Novel Cancer Stem Cell Target for Triple-Negative Breast Cancer

PURPOSE

Although chemotherapies kill most cancer cells, stem cell-enriched survivors seed metastasis, particularly in triple-negative breast cancers (TNBC). TNBCs arise from and are enriched for tumor stem cells. Here, we tested if inhibition of DOT1L, an epigenetic regulator of normal tissue stem/progenitor populations, would target TNBC stem cells.

EXPERIMENTAL DESIGN

Effects of DOT1L inhibition by EPZ-5676 on stem cell properties were tested in three TNBC lines and four patient-derived xenograft (PDX) models and in isolated cancer stem cell (CSC)-enriched ALDH1+ and ALDH1- populations. RNA sequencing compared DOT1L regulated pathways in ALDH1+ and ALDH1- cells. To test if EPZ-5676 decreases CSC in vivo, limiting dilution assays of EPZ-5676/vehicle pretreated ALDH1+ and ALDH1- cells were performed. Tumor latency, growth, and metastasis were evaluated. Antitumor activity was also tested in TNBC PDX and PDX-derived organoids.

RESULTS

ALDH1+ TNBC cells exhibit higher DOT1L and H3K79me2 than ALDH1-. DOT1L maintains MYC expression and self-renewal in ALDH1+ cells. Global profiling revealed that DOT1L governs oxidative phosphorylation, cMyc targets, DNA damage response, and WNT activation in ALDH1+ but not in ALDH1- cells. EPZ-5676 reduced tumorspheres and ALDH1+ cells in vitro and decreased tumor-initiating stem cells and metastasis in xenografts generated from ALDH1+ but not ALDH1- populations in vivo. EPZ-5676 significantly reduced growth in vivo of one of two TNBC PDX tested and decreased clonogenic 3D growth of two other PDX-derived organoid cultures.

CONCLUSIONS

DOT1L emerges as a key CSC regulator in TNBC. Present data support further clinical investigation of DOT1L inhibitors to target stem cell-enriched TNBC.

The Vascular Niche for Adult Cardiac Progenitor Cells

Research on cardiac progenitor cell populations has generated expectations about their potential for cardiac regeneration capacity after acute myocardial infarction and during physiological aging; however, the endogenous capacity of the adult mammalian heart is limited. The modest efficacy of exogenous cell-based treatments can guide the development of new approaches that, alone or in combination, can be applied to boost clinical efficacy. The identification and manipulation of the adult stem cell environment, termed niche, will be critical for providing new evidence on adult stem cell populations and improving stem-cell-based therapies. Here, we review and discuss the state of our understanding of the interaction of adult cardiac progenitor cells with other cardiac cell populations, with a focus on the description of the B-CPC progenitor population (Bmi1+ cardiac progenitor cell), which is a strong candidate progenitor for all main cardiac cell lineages, both in the steady state and after cardiac damage. The set of all interactions should be able to define the vascular cardiac stem cell niche, which is associated with low oxidative stress domains in vasculature, and whose manipulation would offer new hope in the cardiac regeneration field.

CRISPR-mediated knockout of VEGFR2/KDR inhibits cell growth in a squamous thyroid cancer cell line

Squamous and anaplastic thyroid cancers are the most aggressive and life‐threatening cancer types in humans, with the involvement of lymph nodes in 59% of cases and distant metastases in 26% of cases of all thyroid cancers. The median survival of squamous thyroid cancer patients is < 8 months and therefore is of high clinical concern. Here, we show that both VEGFC and VEGFR2/KDR are overexpressed in thyroid cancers, indicating that VEGF/VEGFR signaling plays a carcinogenic role in thyroid cancer development. Using CRISPR/Cas9, we established a KDR knockout (KO) SW579 squamous thyroid cancer cell line that exhibited dramatically decreased colony formation and invasion abilities (30% and 60% reduction, respectively) when compared to scrambled control cells. To validate the potential of KDR as a therapeutic target for thyroid cancers, we used the KDR RTK inhibitor sunitinib. Protein analysis and live/dead assay were performed to demonstrate that sunitinib significantly inhibited cell growth signal transduction and induced cell apoptosis of SW579 cells. These results suggest that selective targeting of KDR may have potential for development into novel anti‐cancer therapies to suppress VEGF/VEGFR‐mediated cancer development in patients with clinical advanced thyroid cancer.

Cancer Stem Cells in Ovarian Cancer-A Source of Tumor Success and a Challenging Target for Novel Therapies

Ovarian cancer is the most lethal neoplasm of the female genital organs. Despite indisputable progress in the treatment of ovarian cancer, the problems of chemo-resistance and recurrent disease are the main obstacles for successful therapy. One of the main reasons for this is the presence of a specific cell population of cancer stem cells. The aim of this review is to show the most contemporary knowledge concerning the biology of ovarian cancer stem cells (OCSCs) and their impact on chemo-resistance and prognosis in ovarian cancer patients, as well as to present the treatment options targeted exclusively on the OCSCs. The review presents data concerning the role of cancer stem cells in general and then concentrates on OCSCs. The surface and intracellular OCSCs markers and their meaning both for cancer biology and clinical prognosis, signaling pathways specifically activated in OCSCs, the genetic and epigenetic regulation of OCSCs function including the recent studies on the non-coding RNA regulation, cooperation between OCSCs and the tumor microenvironment (ovarian cancer niche) including very specific environment such as ascites fluid, the role of shear stress, autophagy and metabolic changes for the function of OCSCs, and finally mechanisms of OCSCs escape from immune surveillance, are described and discussed extensively. The possibilities of anti-OCSCs therapy both in experimental settings and in clinical trials are presented, including the recent II phase clinical trials and immunotherapy. OCSCs are a unique population of cancer cells showing a great plasticity, self-renewal potential and resistance against anti-cancer treatment. They are responsible for the progression and recurrence of the tumor. Several completed and ongoing clinical trials have tested different anti-OCSCs drugs which, however, have shown unsatisfactory efficacy in most cases. We propose a novel approach to ovarian cancer diagnosis and therapy.

A Network Pharmacology Study to Uncover the Mechanism of FDY003 for Ovarian Cancer Treatment

Ovarian cancer (OC) is one of the deadliest gynecological tumors responsible for 0.21 million deaths per year worldwide. Despite the increasing interest in the use of herbal drugs for cancer treatment, their pharmacological effects in OC treatment are not understood from a systems perspective. Using network pharmacology, we determined the anti-OC potential of FDY003 from a comprehensive systems view. We observed that FDY003 suppressed the viability of human OC cells and further chemosensitized them to cytotoxic chemotherapy. Through network pharmacological and pharmacokinetic approaches, we identified 16 active ingredients in FDY003 and their 108 targets associated with OC mechanisms. Functional enrichment investigation revealed that the targets may coordinate diverse cellular behaviors of OC cells, including their growth, proliferation, survival, death, and cell cycle regulation. Furthermore, the FDY003 targets are important constituents of diverse signaling pathways implicated in OC mechanisms (eg, phosphoinositide 3-kinase [PI3K]-Akt, mitogen-activated protein kinase [MAPK], focal adhesion, hypoxia-inducible factor [HIF]-1, estrogen, tumor necrosis factor [TNF], erythroblastic leukemia viral oncogene homolog [ErbB], Janus kinase [JAK]-signal transducer and activator of transcription [STAT], and p53 signaling). In summary, our data present a comprehensive understanding of the anti-OC effects and mechanisms of action of FDY003.

High-grade ovarian cancer associated H/ACA snoRNAs promote cancer cell proliferation and survival

Small nucleolar RNAs (snoRNAs) are an omnipresent class of non-coding RNAs involved in the modification and processing of ribosomal RNA (rRNA). As snoRNAs are required for ribosome production, the increase of which is a hallmark of cancer development, their expression would be expected to increase in proliferating cancer cells. However, assessing the nature and extent of snoRNAs' contribution to cancer biology has been largely limited by difficulties in detecting highly structured RNA. In this study, we used a dedicated midsize non-coding RNA (mncRNA) sensitive sequencing technique to accurately survey the snoRNA abundance in independently verified high-grade serous ovarian carcinoma (HGSC) and serous borderline tumour (SBT) tissues. The results identified SNORA81, SNORA19 and SNORA56 as an H/ACA snoRNA signature capable of discriminating between independent sets of HGSC, SBT and normal tissues. The expression of the signature SNORA81 correlates with the level of ribosomal RNA (rRNA) modification and its knockdown inhibits 28S rRNA pseudouridylation and accumulation leading to reduced cell proliferation and migration. Together our data indicate that specific subsets of H/ACA snoRNAs may promote tumour aggressiveness by inducing rRNA modification and synthesis.

Systemic characterization of alternative splicing related to prognosis, immune infiltration, and drug sensitivity analysis in ovarian cancer

Background

Alternative splicing (AS) plays an essential role in tumorigenesis and progression. This study intended to construct an innovative prognostic model based on AS events to gain more precise survival prediction and search for potential therapeutic targets in ovarian cancer.

Methods

Seven types of AS events in ovarian serous cystadenocarcinoma (OV) patients with RNA-seq were obtained using The Cancer Genome Atlas (TCGA) SpliceSeq tool and database. Cox and Kaplan-Meier curve analyses were employed to establish the prognostic models. Relying on drug sensitivity data from the CellMiner database, Genomics of Drug Sensitivity (GDS) was adopted to estimate the platinum-sensitive analysis. Furthermore, a prognostic splicing factor (SF)-AS network was constructed using Cytoscape. Finally, in order to explore the influence of the tumor microenvironment on the prognosis of OV patients, we first combined a similar network fusion and consensus clustering (SNF-CC) algorithm to identify three OV subtypes based on survival-related AS events and then utilized single-sample Gene Set Enrichment Analysis (ssGSEA) method to perform immune cell infiltration analysis.

Results

A total of 48,049 AS events and 21,841 related genes were selected from 318 OV samples, and 2,206 AS events associated with disease-free survival (DFS) were identified. Multivariate Cox and Kaplan-Meier curve analyses were then employed to establish the prognostic models. Receiver operating characteristic (ROC) analysis from 0.59 to 0.75 showed that these models were highly efficient in distinguishing patient survival. GDS was adopted with the CellMiner database to provide some insights for platinum-sensitive analysis of OV. Furthermore, a prognostic SF-AS network, which discovered a significant connection between SFs and prognostic AS genes, was constructed using Cytoscape. The combined SNF-CC algorithm revealed three distinct OV subtypes based on the prognostic AS events, and the associations between this novel molecular classification and immune cell infiltration were further explored.

Conclusions

We developed a powerful prognostic AS signature for OV and provided a deeper understanding of SF-AS network regulatory mechanisms, as well as platinum-sensitive and cancer immune microenvironments. These results revealed various candidate biomarkers and potential targets for OV treatment strategies.

Exploring the mechanisms of anti-ovarian cancer of Hedyotis diffusa Willd and Scutellaria barbata D. Don through focal adhesion pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Hedyotis diffusa Willd and Scutellaria barbata D.Don (HD-SB) pairing were widely used as traditional medicine known for their anti-tumor effects. However, the inhibitory effect of HD-SB on ovarian cancer and its potential mechanisms were still not clear.

AIM OF THE STUDY

Our study identified the anti-tumor effect of HD-SB on ovarian cancer and analyzed the potential mechanisms by the network pharmacology and molecular docking method.

MATERIALS AND METHODS

The inhibitory effect of HD-SB combination on the growth and migration of ovarian cancer was detected by MTT and transwell assays. The effective ingredients of HD-SB and their potential targets were obtained from the Traditional Chinese Medicines for Systems Pharmacology Database (TCMSP), the GeneCards database, and the UniProt database. The relationships between active ingredients of HD-SB and potential targets or pathways of ovarian cancer were analyzed by String database, Cytoscape 3.7.2 software, and David 6.7 online database. The anti-ovarian cancer targets of HD-SB in the focal adhesion pathway were identified by RT-qPCR and molecular docking.

RESULTS

HD-SB combination significantly inhibited the proliferation and migration of ovarian cancer cells. We observed that the 1:2 ratio of HD-SB had the lowest IC50 value. 60 gene targets of 33 active ingredients in HD-SB were selected by pharmacokinetic parameters. The network pharmacological analysis showed that quercetin, luteolin, and baicalein might be the important anti-ovarian cancer ingredients in HD-SB, and the inhibitory effects of these three ingredients on the proliferation of ovarian cancer cells were verified respectively. Functional enrichment results suggested that HD-SB inhibited ovarian cancer growth and migration mainly through the focal adhesion pathway and the potential targets were EGFR, MAPK1, VEGFA, and PIK3CG.

CONCLUSIONS

HD-SB pairing significantly inhibited the proliferation and migration of ovarian cancer. Using network pharmacological methods and validation experiments, we found that HD-SB might, at least partially, inhibit ovarian cancer through the focal adhesion pathway. We believed that the HD-SB combination could be a potential therapeutic drug for the treatment of ovarian cancer patients.

The Plasticity of Circulating Tumor Cells in Ovarian Cancer During Platinum-containing Chemotherapy

BACKGROUND

Circulating tumor cells (CTCs) are a potential source of metastases and relapses. The data on the ovarian cancer (OC) CTCs molecular characteristics are limited.

OBJECTIVE

To assess the TGFβ, CXCL2, VEGFA and ERCC1 expression in two OC CTC subpopulations before and during chemotherapy (CT), and its relation to clinical characteristics.

METHODS

Two CTCs subpopulations (EpCAM+CK18+E-cadherin+; EpCAM+CK18+Vimentin+) were enriched using immunomagnetic separation before treatment and after 3 cycles of platinum-containing CT. Expression of mRNA was assessed using RT-qPCR.

RESULTS

The study included 31 I-IV stage OC patients. During CT, TGFβ levels increased in both fractions (p=0.054) compared with the initial levels. ERCC1 expression in E-cadherin+ CTCs was higher during neoadjuvant than adjuvant CT (p=0.004). CXCL2 level in E-cadherin+ CTCs increased (p=0.038) during neoadjuvant CT compared with the initial. TGF-β expression in vimentin+ CTCs during CT was negatively correlated to disease stage (p=0.003). Principal component analysis before CT revealed a component combining VEGFA, TGFβ, CXCL2, and a component with ERCC1 and VEGFA; during CT, component 1 contained ERCC1 and VEGFA, component 2 - TGFβ and CXCL2 in both fractions. Increased ERCC1 expression in E-cadherin+ CTCs during CT was associated with decreased progression-free survival (PFS) (HR 1.11 (95% CI 1.03-1.21, p=0.009) in multivariate analysis.

CONCLUSION

EpCAM+ OC CTCs are phenotypically heterogeneous, which may reflect variability in their metastatic potential. CT changes the molecular characteristics of CTCs. Expression of TGFβ in EpCAM+ CTCs increases during CT. High ERCC1 expression in EpCAM+CK18+E-cadherin+ CTCs during CT is associated with decreased PFS in OC.

The Cancer Stem Cell Niche in Ovarian Cancer and Its Impact on Immune Surveillance

Ovarian cancer is an aggressive gynaecological cancer with extremely poor prognosis, due to late diagnosis as well as the development of chemoresistance after first-line therapy. Research advances have found stem-like cells present in ovarian tumours, which exist in a dynamic niche and persist through therapy. The stem cell niche interacts extensively with the immune and non-immune components of the tumour microenvironment. Significant pathways associated with the cancer stem cell niche have been identified which interfere with the immune component of the tumour microenvironment, leading to immune surveillance evasion, dysfunction and suppression. This review aims to summarise current evidence-based knowledge on the cancer stem cell niche within the ovarian cancer tumour microenvironment and its effect on immune surveillance. Furthermore, the review seeks to understand the clinical consequences of this dynamic interaction by highlighting current therapies which target these processes.

Combination of Danshen and ligustrazine has dual anti-inflammatory effect on macrophages and endothelial cells

ETHNOPHARMACOLOGICAL RELEVANCE

Salvia Miltiorrhiza Radix et Rhizoma (Danshen) and Chuanxiong Rhizoma (Chuanxiong) are both traditional Chinese medicines with vascular protective effects, and their combination is widely used in China to treat occlusive or ischemic diseases of the cerebrovascular or cardiovascular system. Although it is widely accepted that these diseases have high relevance to inflammation, little is known about the anti-inflammatory effect of Danshen, Chuanxiong, and their combination.

AIM OF STUDY

We aimed to investigate the complex mode of action of Danshen, Chuanxiong, and their combination and the molecular mechanisms underlying their anti-inflammatory activity. Specifically, toll-like receptor (TLR1/2, 3, and 4)-triggered macrophages and endothelial cells, the two major cell players in atherosclerosis as well as in related cardiovascular and cerebrovascular injuries, were emphasized.

METHODS

TLR1/2-, TLR3-, and TLR4-induced bone marrow macrophages (BMMs) and human umbilical vein endothelial cells (HUVECs) were treated with Danshen extract (S. miltiorrhiza extract, SME), ligustrazine (2, 3, 5, 6-tetramethylpyrazine, TMP), and their combination (S. miltiorrhiza and TMP injection, SLI), respectively. The proinflammatory cytokines interleukin 6 (IL-6), IL-12, and tumor necrosis factor alpha (TNF-α) were detected as the preliminary indicators of inflammation. In addition, RNA sequencing (RNA-seq)-based transcriptional profiling analyses were conducted for TLR2-activated BMMs to determine the molecular mode of action of SLI as well as the contribution of SME to SLI activity.

RESULTS

SLI mitigated inflammation in both BMMs and HUVECs. Refer to the combination, SME had pronounced anti-inflammatory effect on BMMs but had only a slight effect on HUVECs. In contrast, TMP had considerable anti-inflammatory effect on HUVECs but not on BMMs. Bioinformatic analysis identified a broad spectrum of regulatory genes, in addition to IL-6 gene, and C-X-C motif chemokine ligand 10 (CXCL10) appeared to be another key molecule involved in the mechanism underlying SLI and SME effects. At the molecular level, SME was a major contributor of the anti-inflammatory activity of SLI.

CONCLUSIONS

In TLR-activated inflammation, SLI exhibits a "multiple ingredient-multiple target" effect, with SME primarily affecting macrophages and TMP affecting HUVECs. Our study provides evidence for the clinical application of SLI in treating complex diseases involving inflammation-induced injury of both macrophages and epithelial cells. Further bioinformatics studies are required to reveal the entire molecular network involved in TMP, SME, and SLI activity.

CircASH2L Promotes Ovarian Cancer Tumorigenesis, Angiogenesis, and Lymphangiogenesis by Regulating the miR-665/VEGFA Axis as a Competing Endogenous RNA

Ovarian cancer is the leading cause of gynecologic cancer-related deaths. Emerging research has revealed a close relationship between circular RNAs (circRNAs) and ovarian cancer development, metastasis, and prognosis. The objective of our research was to further explore the relationship between circASH2L and ovarian cancer. Quantitative real-time polymerase chain reaction was used to detect the differential expression of circRNAs between normal ovaries and ovarian cancer tissues. The impact of circASH2L on the proliferation, invasion, and tumorigenicity of ovarian cancer cells was evaluated using gain- and loss-of-function experiments. The molecular mechanisms of circASH2L function were investigated using bioinformatics analysis, RNA fluorescence in situ hybridization, western blots, and dual-luciferase reporter assays. The results showed that circASH2L was remarkably upregulated in ovarian cancer. The invasion and growth of ovarian cancer cells were suppressed by circASH2L knockdown in vitro, and downregulation of circASH2L restrained both angiogenesis and lymphangiogenesis of tumor xenografts in vivo. Furthermore, circASH2L was mostly distributed in the cytoplasm, where it competes with vascular endothelial growth factor A (VEGFA) for binding to miR-665. These findings indicate that circASH2L has an oncogenic function in ovarian cancer. In conclusion, circASH2L plays a critical role in regulating ovarian cancer cell tumorigenesis, angiogenesis, and lymphangiogenesis through the miR-665/VEGFA axis and, therefore, is a possible candidate target for ovarian cancer treatment.

Extended transcriptome analysis reveals genome-wide lncRNA-mediated epigenetic dysregulation in colorectal cancer

It is estimated that the rate of epigenetic changes may be orders of magnitude higher than that of genetic changes and that purely epigenetic mechanisms may explain why cancers arise with few or no recurrent mutations. However, supporting evidence remains limited, partly due to the cost of experimentally studying genome-wide epigenetic dysregulation. Since genome modification enzymes are recruited by long noncoding RNAs (lncRNAs) to specific genomic sites, analyzing differentially expressed genes and differentially methylated regions (DMRs) at the DNA binding sites of differentially expressed lncRNAs is important for uncovering epigenetic dysregulation. We performed RNA-seq and MeDIP-seq on a set of colorectal cancer (CRC) and normal colon samples and developed an analysis pipeline for combined analyses of gene expression, DNA methylation, and lncRNA/DNA binding. The genes identified in our data and important for CRC agree with widely reported findings. We found that aberrantly transcribed noncoding transcripts may epigenetically dysregulate genes, that correlated gene expression is significantly determined by epigenetic dysregulation, that differentially expressed noncoding transcripts and their epigenetic targets form distinct modules in different cancer cells, and that many hub lncRNAs in these modules are primate-specific. These results suggest that lncRNA-mediated epigenetic dysregulation greatly determines aberrant gene expression and that epigenetic dysregulation is highly species-specific. The analysis pipeline can effectively unveil cancer- and cell-specific modules of epigenetic dysregulation, and such modules may provide novel clues for identifying diagnostic, therapeutic, and prognostic targets for epigenetic dysregulation.

miR-106a-5p Functions as a Tumor Suppressor by Targeting VEGFA in Renal Cell Carcinoma

MicroRNAs (miRNAs) regulate progression of different cancers. Nevertheless, there is limited information regarding the role of miR-106a-5p in renal cell carcinoma (RCC). Herein, we demonstrate that miR-106a-5p levels are drastically decreased in clear cell RCC (ccRCC) tissues and cell lines, which subsequently contribute to a poor patient overall survival and a high tumor stage. By screening and analyzing, we found that miR-106a-5p directly targets the 3′-UTR of the VEGFA mRNA and led to a decrease in VEGFA. This process is important for tumor cells' growth and colony formation, and overexpression of miR-106a-5p can especially kill kidney tumor cells. Therefore, our data reveal that miR-106a-5p functions as a tumor suppressor by regulating VEGFA and ccRCC may be susceptible to miR-106a-5p therapy.

Inhibition of VEGFA Increases the Sensitivity of Ovarian Cancer Cells to Chemotherapy by Suppressing VEGFA-Mediated Autophagy

Background

Ovarian cancer (OvCa) is the leading cause of death of gynecological malignancies worldwide. Vascular endothelial growth factor A (VEGFA), the most potent angiogenic factor, is responsible for tumor growth and angiogenesis, but its role in OvCa chemotherapy resistance remains unclear.

Methods

RT-PCR and Western blot were used to detect VEGFA expression in tumor cells and normal ovarian surface epithelial cells. Gene Ontology (GO) enrichment analysis was used to analyze GO terms correlated with VEGFA. In in vitro experiments, we knockdown VEGFA in tumor cells and detected the tumor cell viability and apoptosis after chemotherapy drug treatment by MTT assay and flow cytometry. Western blot was used to detect autophagy and apoptosis related proteins.

Results

We proved that VEGFA was highly expressed in tumor cells comparted with normal ovarian surface epithelial cells, and enriched GO analysis of VEGFA showed that VEGFA was involved in anti-apoptotic process. Further in vitro experiments confirmed that expression of VEGFA was correlated with chemotherapy resistance and this effect was mediated by autophagy. Meanwhile tumor cells treated with chemotherapy drugs also promoted the expression of VEGFA. Knockdown VEGFA inhibited autophagy of tumor cells and thus potents the killing efficiency in DDP resistant tumor cells and this effect could be reversed by the addition of recombinant VEGFA.

Conclusion

Taken together, our study demonstrates that VEGFA is involved in anti-apoptosis of tumor cells to chemotherapy, killing partly through autophagy, indicating that VEGFA may serve as a potential target to improve chemotherapy treatment.

Role of miR-302/367 cluster in human physiology and pathophysiology

MicroRNAs (miRNAs) are small non-coding RNAs that negatively regulate target mRNAs at the post-transcriptional level. Increasing evidence shows the involvement of miRNAs in diverse biological processes. miR-302/367 cluster is highly conserved among vertebrates and made up of five members, including miR-367, miR-302a, miR-302b, miR-302c and miR-302d. miR-302/367 cluster plays an important role in cell proliferation, differentiation and reprogramming, affecting the development of tumor, cardiovascular system, nervous system and immune system. In this review, we will summarize the role of miR-302/367 cluster in embryonic stem cells and induced pluripotent stem cells and try to point out its relationship with tumors, cardiovascular system, nervous system and immune system.

Stigmasterol Causes Ovarian Cancer Cell Apoptosis by Inducing Endoplasmic Reticulum and Mitochondrial Dysfunction

Background: Phytosterols have physiological effects and are used as medicines or food supplements. Stigmasterol has shown anticancer effects against various cancers such as hepatoma, cholangiocarcinoma, gall bladder carcinoma, endometrial adenocarcinoma and skin, gastric, breast, prostate, and cervical cancer. However, there are no reports on stigmasterol’s effects on ovarian cancer. Methods: We investigated the effects of stigmasterol on proapoptotic signals, mitochondrial function, reactive oxygen species production, and the cytosolic and mitochondrial calcium levels in human ovarian cancer cells, to understand the mechanisms underlying the effects of stigmasterol on ovarian cancer cells. We also conducted migration assay to confirm whether that stigmasterol inhibits ovarian cancer cell migration. Results: Stigmasterol inhibited development of human ovarian cancer cells. However, it induced cell apoptosis, ROS production, and calcium overload in ES2 and OV90 cells. In addition, stigmasterol stimulated cell death by activating the ER-mitochondrial axis. We confirmed that stigmasterol suppressed cell migration and angiogenesis genes in human ovarian cancer cells. Conclusions: Our findings suggest that stigmasterol can be used as a new treatment for ovarian cancer.

Current Molecular Targeted Agents for Advanced Gastric Cancer

Gastric cancer is the third leading cause of malignant tumor-related mortality worldwide. Traditional cytotoxic agents prolong the overall survival and progression-free survival of patients with advanced gastric cancer (AGC) compared to that with best supportive care. Due to the occurrence of serious adverse drug reactions that result in discontinued treatment, the survival benefit in AGC remains unsatisfactory. Systemic chemotherapy regimens have changed greatly, especially since the introduction of trastuzumab. Nevertheless, HER2 positivity is present in only approximately 20% of tumors. Due to the genetic heterogeneity and complexity of patients, there are many studies in progress that are exploring novel targeted drugs as an alternative to chemotherapy or adjuvant treatment in early-stage, progressive, and advanced gastric cancer. On the basis of the differences in gene expression profiles among patients, searching for specific and sensitive predictive biomarkers is important for identifying patients who will benefit from a specific targeted drug. With the development of targeted therapies and available chemotherapeutic drugs, there is no doubt that, over time, more patients will achieve better survival outcomes. Recently, immune checkpoint blockade has been well developed as a promising anticancer strategy. This review outlines the currently available information on clinically tested molecular targeted drugs and immune checkpoint inhibitors for AGC to provide support for decision-making in clinical practice.

Novel Therapeutic Strategies for Ovarian Cancer Stem Cells

Ovarian cancer (OC) is one of the most lethal gynecologic malignancies. Due to the lack of specific symptoms and screening methods, this disease is usually diagnosed only at an advanced and metastatic stage. The gold-standard treatment for OC patients consists of debulking surgery followed by taxane combined with platinum-based chemotherapy. Most patients show complete clinical remission after first-line therapy, but the majority of them ultimately relapse, developing radio- and chemoresistant tumors. It is now proposed that the cause of recurrence and reduced therapy efficacy is the presence of small populations of cancer stem cells (CSCs). These cells are usually resistant against conventional cancer therapies and for this reason, effective targeted therapies for the complete eradication of CSCs are urgently needed. In this review article, we highlight the mechanisms of CSC therapy resistance, epithelial-to-mesenchymal transition, stemness, and novel therapeutic strategies for ovarian CSCs.

A single-nucleotide polymorphism in lnc-LAMC2-1:1 interferes with its interaction with miR-128 to alter the expression of deleted in colorectal cancer and its effect on the survival rate of subjects with ovarian cancer

This study aimed to identify the association between lnc-LAMC2-1:1 polymorphism rs2147578 and the recurrence of ovary cancer, as well as to study the underlying mechanism of rs2147578 in ovary cancer. Real-time polymerase chain reaction, Western blot analysis, immunohistochemistry, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, Logrank test, and Kaplan-Meier analysis were carried out to explore the role of rs2147578 in ovary cancer. No obvious difference was observed concerning all clinical characteristics among 90 patients genotyped as CC (N = 28), CG (N = 38), and GG (N = 24) in their rs2147578 polymorphism. In addition, the subjects carrying the CC genotype had longer recurrence-free survival time and showed a lower level of malignancy compared with those carrying CG and GG genotypes. Lnc-LAMC2-1:1 and miR-128 were lowly expressed in the CC group, while deleted in colorectal cancer (DCC) was highly expressed in the CC group. Furthermore, DCC was identified as a target gene of miR-128, and miR-128 mimics decreased the luciferase activity of cells cotransfected with wild-type DCC 3'-untranslated region. Lnc-LAMC2:1-1 directly targeted and affected miR-128 expression, and the G allele in lnc-LAMC2-1:1 rs2147578 upregulated miR-128 expression. Transfection with a miR-128 precursor evidently downregulated the expression of lnc-LAMC2-1:1, miR-128, and DCC expression, but did not affect the expression of ABCC5 and body mass index. Finally, miR-128 precursor promoted cell proliferation and inhibited cell apoptosis. Compared with lnc-LAMC2-1:1 rs2147578C allele, the G allele increases the risk of ovarian cancer by reducing the binding between lnc-LAMC2-1:1 and miR-128-3p, which in turn further decreases the expression of DCC and inhibits cell apoptosis.

Dual-platform affinity proteomics identifies links between the recurrence of ovarian carcinoma and proteins released into the tumor microenvironment

The peritoneal fluid (ascites), replete with abundant tumor-promoting factors and extracellular vesicles (EVs) reflecting the tumor secretome, plays an essential role in ovarian high-grade serous carcinoma (HGSC) metastasis and immune suppression. A comprehensive picture of mediators impacting HGSC progression is, however, not available.

Methods: Proteins in ascites from HGSC patients were quantified by the aptamer-based SOMAscan affinity proteomic platform. SOMAscan data were analyzed by bioinformatic methods to reveal clinically relevant links and functional connections, and were validated using the antibody-based proximity extension assay (PEA) Olink platform. Mass spectrometry was used to identify proteins in extracellular microvesicles released by HGSC cells.

Results: Consistent with the clinical features of HGSC, 779 proteins in ascites identified by SOMAscan clustered into groups associated either with metastasis and a short relapse-free survival (RFS), or with immune regulation and a favorable RFS. In total, 346 proteins were linked to OC recurrence in either direction. Reanalysis of 214 of these proteins by PEA revealed an excellent median Spearman inter-platform correlation of ρ=0.82 for the 46 positively RFS-associated proteins in both datasets. Intriguingly, many proteins strongly associated with clinical outcome were constituents of extracellular vesicles. These include proteins either linked to a poor RFS, such as HSPA1A, BCAM and DKK1, or associated with a favorable outcome, such as the protein kinase LCK. Finally, based on these data we defined two protein signatures that clearly classify short-term and long-term relapse-free survivors.

Conclusion: The ascites secretome points to metastasis-promoting events and an anti-tumor response as the major determinants of the clinical outcome of HGSC. Relevant proteins include both bone fide secreted and vesicle-encapsulated polypeptides, many of which have previously not been linked to HGSC recurrence. Besides a deeper understanding of the HGSC microenvironment our data provide novel potential tools for HGSC patient stratification. Furthermore, the first large-scale inter-platform validation of SOMAscan and PEA will be invaluable for other studies using these affinity proteomics platforms.

PRC1 gene silencing inhibits proliferation, invasion, and angiogenesis of retinoblastoma cells through the inhibition of the Wnt/β-catenin signaling pathway

Retinoblastoma is an ocular malignancy occurring in childhood. The current study evaluates the ability of silenced PRC1 on retinoblastoma cell proliferation, and angiogenesis via the Wnt/β-catenin signaling pathway. A total of 36 cases of retinoblastoma tissues (n = 36) and normal retinal tissues (n = 10) were selected in the current study. Retinoblastoma cells presenting with the high PRC1 messenger RNA (mRNA) expression were selected among the WERI-Rb-1, HXO-RB44, Y79, SO-Rb50, and SO-Rb70 cells lines, and were transfected with siRNA-PRC1 and LiCl (the activator of the Wnt/β-catenin pathway). The expressions of PRC1, VEGF, Wnt1, β-catenin, CyclinD1, extent of β-catenin, and GSK-3β phosphorylation were evaluated. Cell proliferation, cell-cycle distribution, and cell invasion of retinoblastoma cells were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry, and Transwell assay. The angiogenesis of retinoblastoma cells was detected by tube formation assay. HXO-RB44 and WERI-Rb-1 cells were selected owing to the highest PRC1 mRNA expression. Meanwhile, PRC2 gene silencing presented lower expression levels of PRC1, VEGF, Wnt1, β-catenin, CyclinD1, extent of β-catenin and GSK-3β phosphorylation, decreased proliferation and invasion abilities, extended G0/G1 phase, and shortened S and G2/M phases of HXO-RB44 and WERI-Rb-1 cells, suggesting the silenced PRC2 inactivated Wnt/β-catenin pathway, so as to further restrain the retinoblastoma cell proliferation, invasion, and angiogenesis. These results support the view that PRC1 gene silencing could suppress the proliferation, and angiogenesis of retinoblastoma cells by repressing the Wnt/β-catenin pathway.

Hypoxia promotes vasculogenic mimicry formation by vascular endothelial growth factor A mediating epithelial-mesenchymal transition in salivary adenoid cystic carcinoma

Objectives

To investigate the role of hypoxia in vasculogenic mimicry (VM) of salivary adenoid cystic carcinoma (SACC) and the underlying mechanism involved.

Materials and methods

Firstly, wound healing, transwell invasion, immunofluorescence and tube formation assays were performed to measure the effect of hypoxia on migration, invasion, EMT and VM of SACC cells, respectively. Then, immunofluorescence and RT‐PCR were used to detect the effect of hypoxia on VE‐cadherin and VEGFA expression. And pro‐vasculogenic mimicry effect of VEGFA was investigated by confocal laser scanning microscopy and Western blot. Moreover, the levels of E‐cadherin, N‐cadherin, Vimentin, CD44 and ALDH1 were determined by Western blot and immunofluorescence in SACC cells treated by exogenous VEGFA or bevacizumab. Finally, CD31/ PAS staining was performed to observe VM and immunohistochemistry was used to determine the levels of VEGFA and HIF‐1α in 95 SACC patients. The relationships between VM and clinicopathological variables, VEGFA or HIF‐1α level were analysed.

Results

Hypoxia promoted cell migration, invasion, EMT and VM formation, and enhanced VE‐cadherin and VEGFA expression in SACC cells. Further, exogenous VEGFA markedly increased the levels of N‐cadherin, Vimentin, CD44 and ALDH1, and inhibited the expression of E‐cadherin, while the VEGFA inhibitor reversed these changes. In addition, VM channels existed in 25 of 95 SACC samples, and there was a strong positive correlation between VM and clinic stage, distant metastases, VEGFA and HIF‐1α expression.

Conclusions

VEGFA played an important role in hypoxia‐induced VM through regulating EMT and stemness, which may eventually fuel the migration and invasion of SACC.

Effect of Weightlessness on the 3D Structure Formation and Physiologic Function of Human Cancer Cells

With the rapid development of modern medical technology and the deterioration of living environments, cancer, the most important disease that threatens human health, has attracted increasing concerns. Although remarkable achievements have been made in tumor research during the past several decades, a series of problems such as tumor metastasis and drug resistance still need to be solved. Recently, relevant physiological changes during space exploration have attracted much attention. Thus, space exploration might provide some inspiration for cancer research. Using on ground different methods in order to simulate microgravity, structure and function of cancer cells undergo many unique changes, such as cell aggregation to form 3D spheroids, cell-cycle inhibition, and changes in migration ability and apoptosis. Although numerous better experiments have been conducted on this subject, the results are not consistent. The reason might be that different methods for simulation have been used, including clinostats, random positioning machine (RPM) and rotating wall vessel (RWV) and so on. Therefore, we review the relevant research and try to explain novel mechanisms underlying tumor cell changes under weightlessness.

Age-related oxidative stress confines damage-responsive Bmi1+ cells to perivascular regions in the murine adult heart

Adult progenitor cells reside in specialized microenvironments which maintain their undifferentiated cell state and trigger regenerative responses following injury. Although these environments are well described in several tissues, the cellular components that comprise the cardiac environment where progenitor cells are located remain unknown. Here we use Bmi1^CreERT and Bmi1^GFP mice as genetic tools to trace cardiac damage-responsive cells throughout the mouse lifespan. In adolescent mice, Bmi1⁺ damage-responsive cells are broadly distributed throughout the myocardium. In adult mice, however, Bmi1⁺ cells are confined predominately in perivascular areas with low levels of reactive oxygen species (ROS) and their number decline in an age-dependent manner. In vitro co-culture experiments with endothelial cells supported a regulatory role of the endothelium in damage-responsive cell behavior. Accordingly, in vivo genetic decrease of ROS levels in adult heart disengaged Bmi1⁺ cells from the cardiovascular network, recapitulating an adolescent-like Bmi1 expression profile. Thus, we identify cardiac perivascular regions as low-stress microenvironments that favor the maintenance of adult damage-responsive cells.

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Bmi1⁺ cardiac damage-responsive cells are sheltered in areas with low ROS levels.

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Aging-related oxidative damage confines cardiac Bmi1⁺ cells to perivascular regions.

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Microvasculature-derived signals regulate adult Bmi1⁺ damage-responsive cell behavior.

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Genetic ROS levels manipulation modifies the percentage and identity of Bmi1⁺ cells.

VEGFR2 promotes tumorigenesis and metastasis in a pro-angiogenic-independent way in gastric cancer

Background

VEGF/VEGFR2 pathway is the central therapeutic target in anti-angiogenic treatment in multiple cancers. However, little work has been carried out concerning the pro-malignancy functions of VEGFR2 that are independent of its pro-angiogenesis effects in gastric cancer. Here, we demonstrated that VEGFR2 up-regulation in gastric cancer tissues was a prognostic marker for poor disease-free survival and overall survival of gastric cancer patients.

Methods

Immunohistochemistry was used to detect VEGFR2 and VTN expressions in specimens. Kaplan–Meier curves were constructed for survival analysis. Stably knockdown cell lines and overexpression cell lines were constructed by small interfering RNA and plasmids transfection. Real-time PCR and Western blot were used to confirm the expressions of target genes at both RNA and protein levels. Cell proliferation was measured by using Cell Counting Kit-8 and xenograft models. Microarray and bioinformatic analysis were also performed to identify the relationship between Vitronectin (VTN) and VEGFR2.

Results

When overexpressed in gastric cancer cells, VEGFR2 increased cellular proliferation and invasion in vitro and tumor formation in xenograft models. By using integrating microarray and bioinformatic analysis, we identifiedVTN as a downstream of VEGFR2 pathway. In gain- and loss-of function analysis in gastric cancer cells, VTN was further verified in consistent with VEGFR2 in expression levels and in regulating cell growth and motility in vitro and in vivo. Moreover, in gastric cancer samples, VTN was as also revealed as a poor prognostic factor.

Conclusions

Our present findings defined a novel activity for VEGFR2 in promoting tumorogenicity, motility and indicating a poor survival in gastric cancer beyond its known pro-angiogenic effects.

Implications

Our present findings defined a novel activity for VEGFR2 in promoting tumorogenicity, motility and indicating a poor survival in gastric cancer beyond its known pro-angiogenic effects, which may provide a new and valuable target for design of therapies for intervention and a new cognitive perspective for the anti-angiogenesis therapies.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5322-0) contains supplementary material, which is available to authorized users.

Dual Src and MEK Inhibition Decreases Ovarian Cancer Growth and Targets Tumor Initiating Stem-Like Cells

Purpose: Rational targeted therapies are needed for treatment of ovarian cancers. Signaling kinases Src and MAPK are activated in high-grade serous ovarian cancer (HGSOC). Here, we tested the frequency of activation of both kinases in HGSOC and the therapeutic potential of dual kinase inhibition.Experimental Design: MEK and Src activation was assayed in primary HGSOC from The Cancer Genome Atlas (TGGA). Effects of dual kinase inhibition were assayed on cell-cycle, apoptosis, gene, and proteomic analysis; cancer stem cells; and xenografts.Results: Both Src and MAPK are coactivated in 31% of HGSOC, and this associates with worse overall survival on multivariate analysis. Frequent dual kinase activation in HGSOC led us to assay the efficacy of combined Src and MEK inhibition. Treatment of established lines and primary ovarian cancer cultures with Src and MEK inhibitors saracatinib and selumetinib, respectively, showed target kinase inhibition and synergistic induction of apoptosis and cell-cycle arrest in vitro, and tumor inhibition in xenografts. Gene expression and proteomic analysis confirmed cell-cycle inhibition and autophagy. Dual therapy also potently inhibited tumor-initiating cells. Src and MAPK were both activated in tumor-initiating populations. Combination treatment followed by drug washout decreased sphere formation and ALDH1+ cells. In vivo, tumors dissociated after dual therapy showed a marked decrease in ALDH1 staining, sphere formation, and loss of tumor-initiating cells upon serial xenografting.Conclusions: Selumetinib added to saracatinib overcomes EGFR/HER2/ERBB2-mediated bypass activation of MEK/MAPK observed with saracatinib alone and targets tumor-initiating ovarian cancer populations, supporting further evaluation of combined Src-MEK inhibition in clinical trials. Clin Cancer Res; 24(19); 4874-86. ©2018 AACR.

Targeting cancer stem cells and their niche: perspectives for future therapeutic targets and strategies

A small subpopulation of cells within the bulk of tumors share features with somatic stem cells, in that, they are capable of self-renewal, they differentiate, and are highly resistant to conventional therapy. These cells have been referred to as cancer stem cells (CSCs). Recent reports support the central importance of a cancer stem cell-like niche that appears to help foster the generation and maintenance of CSCs. In response to signals provided by this microenvironment, CSCs express the tumorigenic characteristics that can drive tumor metastasis by the induction of epithelial-mesenchymal-transition (EMT) that in turn fosters the migration and recolonization of the cells as secondary tumors within metastatic niches. We summarize here recent advances in cancer stem cell research including the characterization of their genetic and epigenetic features, metabolic specialities, and crosstalk with aging-associated processes. Potential strategies for targeting CSCs, and their niche, by regulating CSCs plasticity, or therapeutic sensitivity is discussed. Finally, it is hoped that new strategies and related therapeutic approaches as outlined here may help prevent the formation of the metastatic niche, as well as counter tumor progression and metastatic growth.

VEGF-A inhibits agonist-mediated Ca2+ responses and activation of IKCa channels in mouse resistance artery endothelial cells

KEY POINTS

Prolonged exposure to vascular endothelial growth factor A (VEGF-A) inhibits agonist-mediated endothelial cell Ca²⁺ release and subsequent activation of intermediate conductance Ca²⁺ -activated K⁺ (IK_Ca ) channels, which underpins vasodilatation as a result of endothelium-dependent hyperpolarization (EDH) in mouse resistance arteries. Signalling via mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK) downstream of VEGF-A was required to attenuate endothelial cell Ca²⁺ responses and the EDH-vasodilatation mediated by IK_Ca activation. VEGF-A exposure did not modify vasodilatation as a result of the direct activation of IK_Ca channels, nor the pattern of expression of inositol 1,4,5-trisphosphate receptor 1 within endothelial cells of resistance arteries. These results indicate a novel role for VEGF-A in resistance arteries and suggest a new avenue for investigation into the role of VEGF-A in cardiovascular diseases.

ABSTRACT

Vascular endothelial growth factor A (VEGF-A) is a potent permeability and angiogenic factor that is also associated with the remodelling of the microvasculature. Elevated VEGF-A levels are linked to a significant increase in the risk of cardiovascular dysfunction, although it is unclear how VEGF-A has a detrimental, disease-related effect. Small resistance arteries are central determinants of peripheral resistance and endothelium-dependent hyperpolarization (EDH) is the predominant mechanism by which these arteries vasodilate. Using isolated, pressurized resistance arteries, we demonstrate that VEGF-A acts via VEGF receptor-2 (R2) to inhibit both endothelial cell (EC) Ca²⁺ release and the associated EDH vasodilatation mediated by intermediate conductance Ca²⁺ -activated K⁺ (IK_Ca ) channels. Importantly, VEGF-A had no direct effect against IK_Ca channels. Instead, the inhibition was crucially reliant on the downstream activation of the mitogen-activated protein/extracellular signal-regulated kinase kinase 1/2 (MEK1/2). The distribution of EC inositol 1,4,5-trisphosphate (IP₃ ) receptor-1 (R1) was not affected by exposure to VEGF-A and we propose an inhibition of IP₃ R1 through the MEK pathway, probably via ERK1/2. Inhibition of EC Ca²⁺ via VEGFR2 has profound implications for EDH-mediated dilatation of resistance arteries and could provide a mechanism by which elevated VEGF-A contributes towards cardiovascular dysfunction.

Ovarian Cancers: Genetic Abnormalities, Tumor Heterogeneity and Progression, Clonal Evolution and Cancer Stem Cells

Four main histological subtypes of ovarian cancer exist: serous (the most frequent), endometrioid, mucinous and clear cell; in each subtype, low and high grade. The large majority of ovarian cancers are diagnosed as high-grade serous ovarian cancers (HGS-OvCas). TP53 is the most frequently mutated gene in HGS-OvCas; about 50% of these tumors displayed defective homologous recombination due to germline and somatic BRCA mutations, epigenetic inactivation of BRCA and abnormalities of DNA repair genes; somatic copy number alterations are frequent in these tumors and some of them are associated with prognosis; defective NOTCH, RAS/MEK, PI3K and FOXM1 pathway signaling is frequent. Other histological subtypes were characterized by a different mutational spectrum: LGS-OvCas have increased frequency of BRAF and RAS mutations; mucinous cancers have mutation in ARID1A, PIK3CA, PTEN, CTNNB1 and RAS. Intensive research was focused to characterize ovarian cancer stem cells, based on positivity for some markers, including CD133, CD44, CD117, CD24, EpCAM, LY6A, ALDH1. Ovarian cancer cells have an intrinsic plasticity, thus explaining that in a single tumor more than one cell subpopulation, may exhibit tumor-initiating capacity. The improvements in our understanding of the molecular and cellular basis of ovarian cancers should lead to more efficacious treatments.

The use of natural compounds for the targeting and chemoprevention of ovarian cancer

Among gynaecological cancers, ovarian cancer represents the leading cause of death in women. Current treatment for ovarian cancer entails surgery followed by combined chemotherapy with platinum and taxane, which are associated, particularly cisplatin, with severe side effects. While this treatment approach appears to be initially effective in a high number of patients, nearly 70% of them suffer a relapse within a few months after initial treatment. Therefore, more effective and better-tolerated treatment options are clearly needed. In recent years, several natural compounds (such as curcumin, epigallocatechin 3-gallate (EGCG), resveratrol, sulforaphane and Withaferin-A), characterized by long-term safety and negligible and/or inexistent side effects, have been proposed as possible adjuvants of traditional chemotherapy. Indeed, several in vitro and in vivo studies have shown that phytocompounds can effectively inhibit tumor cell proliferation, stimulate autophagy, induce apoptosis, and specifically target ovarian cancer stem cells (CSCs), which are generally considered to be responsible for tumor recurrence in several types of cancer. Here we review current literature on the role of natural products in ovarian cancer chemoprevention, highlighting their effects particularly on the regulation of inflammation, autophagy, proliferation and apoptosis, chemotherapy resistance, and ovarian CSC growth.

VEGFA activates an epigenetic pathway upregulating ovarian cancer-initiating cells

The angiogenic factor, VEGFA, is a therapeutic target in ovarian cancer (OVCA). VEGFA can also stimulate stem‐like cells in certain cancers, but mechanisms thereof are poorly understood. Here, we show that VEGFA mediates stem cell actions in primary human OVCA culture and OVCA lines via VEGFR2‐dependent Src activation to upregulate Bmi1, tumor spheres, and ALDH1 activity. The VEGFA‐mediated increase in spheres was abrogated by Src inhibition or SRC knockdown. VEGFA stimulated sphere formation only in the ALDH1⁺ subpopulation and increased OVCA‐initiating cells and tumor formation in vivo through Bmi1. In contrast to its action in hemopoietic malignancies, DNA methyl transferase 3A (DNMT3A) appears to play a pro‐oncogenic role in ovarian cancer. VEGFA‐driven Src increased DNMT3A leading to miR‐128‐2 methylation and upregulation of Bmi1 to increase stem‐like cells. SRC knockdown was rescued by antagomir to miR‐128. DNMT3A knockdown prevented VEGFA‐driven miR‐128‐2 loss, and the increase in Bmi1 and tumor spheres. Analysis of over 1,300 primary human OVCAs revealed an aggressive subset in which high VEGFA is associated with miR‐128‐2 loss. Thus, VEGFA stimulates OVCA stem‐like cells through Src‐DNMT3A‐driven miR‐128‐2 methylation and Bmi1 upregulation.

The Crosstalk between Ovarian Cancer Stem Cell Niche and the Tumor Microenvironment

Ovarian cancer is one of the most important causes of cancer-related death among women in the world. Despite advances in ovarian cancer treatment, 70–80% of women who initially respond to therapy eventually relapse and die. There is evidence that a small population of cells within the tumors called cancer stem cells (CSCs) could be responsible for treatment failure due to their enhanced chemoresistance and tumorigenicity. These cells reside in a niche that maintains the principal properties of CSCs. These properties are associated with the capacity of CSCs to interact with different cells of the tumor microenvironment including mesenchymal stem cells, endothelial cells, immune cells, and fibroblasts, promoting cancer progression. This interaction can be mediated by cytokines, growth factors, lipids, and/or extracellular vesicles released in the CSC niche. In this review, we will discuss how the interaction between ovarian CSCs and the tumor microenvironment can contribute to the maintenance of the CSC niche and consequently to tumor progression in ovarian cancer.