OCT4 mediates FSH-induced epithelial-mesenchymal transition and invasion through the ERK1/2 signaling pathway in epithelial ovarian cancer

Proneurogenic actions of follicle-stimulating hormone on neurospheres derived from ovarian cortical cells in vitro

BACKGROUND

Neural stem and progenitor cells (NSPCs) from extra-neural origin represent a valuable tool for autologous cell therapy and research in neurogenesis. Identification of proneurogenic biomolecules on NSPCs would improve the success of cell therapies for neurodegenerative diseases. Preliminary data suggested that follicle-stimulating hormone (FSH) might act in this fashion. This study was aimed to elucidate whether FSH promotes development, self-renewal, and is proneurogenic on neurospheres (NS) derived from sheep ovarian cortical cells (OCCs). Two culture strategies were carried out: (a) long-term, 21-days NS culture (control vs. FSH group) with NS morphometric evaluation, gene expression analyses of stemness and lineage markers, and immunolocalization of NSPCs antigens; (b) NS assay to demonstrate FSH actions on self-renewal and differentiation capacity of NS cultured with one of three defined media: M1: positive control with EGF/FGF2; M2: control; and M3: M2 supplemented with FSH.

RESULTS

In long-term cultures, FSH increased NS diameters with respect to control group (302.90 ± 25.20 μm vs. 183.20 ± 7.63 on day 9, respectively), upregulated nestin (days 15/21), Sox2 (day 21) and Pax6 (days 15/21) and increased the percentages of cells immunolocalizing these proteins. During NS assays, FSH stimulated NSCPs proliferation, and self-renewal, increasing NS diameters during the two expansion periods and the expression of the neuron precursor transcript DCX during the second one. In the FSH-group there were more frequent cell-bridges among neighbouring NS.

CONCLUSIONS

FSH is a proneurogenic hormone that promotes OCC-NSPCs self-renewal and NS development. Future studies will be necessary to support the proneurogenic actions of FSH and its potential use in basic and applied research related to cell therapy.

Defining the Role of Metastasis-Initiating Cells in Promoting Carcinogenesis in Ovarian Cancer

Ovarian cancer is the deadliest gynecological malignancy with a high prevalence of transcoelomic metastasis. Metastasis is a multi-step process and only a small percentage of cancer cells, metastasis-initiating cells (MICs), have the capacity to finally establish metastatic lesions. These MICs maintain a certain level of stemness that allows them to differentiate into other cell types with distinct transcriptomic profiles and swiftly adapt to external stresses. Furthermore, they can coordinate with the microenvironment, through reciprocal interactions, to invade and establish metastases. Therefore, identifying, characterizing, and targeting MICs is a promising strategy to counter the spread of ovarian cancer. In this review, we provided an overview of OC MICs in the context of characterization, identification through cell surface markers, and their interactions with the metastatic niche to promote metastatic colonization.

Regulation of the aryl hydrocarbon receptor in cancer and cancer stem cells of gynecological malignancies: An update on signaling pathways

Gynecological malignancies are a female type of cancers that affects the reproductive system. Cancer metastasis or recurrence mediated by cellular invasiveness occurs at advanced stages of cancer progression. Cancer Stem Cells (CSCs) enrichment in tumors leads to chemoresistance, which results in cancer mortality. Exposure to environmental pollutants such as polycyclic aromatic hydrocarbons is associated with an increased the risk of CSC enrichment in gynecological cancers. One of the important pathways that mediates the metabolism and bioactivation of these environmental chemicals is the transcription factor, aryl hydrocarbon receptor (AhR). The present review explores the molecular mechanisms regulating the crosstalk and interaction of the AhR with cancer-related signaling pathways, such as apoptosis, epithelial-mesenchymal transition, immune checkpoints, and G-protein-coupled receptors in several gynecological malignancies such as ovarian, uterine, endometrial, and cervical cancers. The review also discusses the potential of targeting the AhR pathway as a novel chemotherapy for gynecological cancers.

Notch signaling in female cancers: a multifaceted node to overcome drug resistance

Drug resistance is one of the main challenges in cancer therapy, including in the treatment of female-specific malignancies, which account for more than 60% of cancer cases among women. Therefore, elucidating the underlying molecular mechanisms is an urgent need in gynecological cancers to foster novel therapeutic approaches. Notably, Notch signaling, including either receptors or ligands, has emerged as a promising candidate given its multifaceted role in almost all of the hallmarks of cancer. Concerning the connection between Notch pathway and drug resistance in the afore-mentioned tumor contexts, several studies focused on the Notch-dependent regulation of the cancer stem cell (CSC) subpopulation or the induction of the epithelial-to-mesenchymal transition (EMT), both features implicated in either intrinsic or acquired resistance. Indeed, the present review provides an up-to-date overview of the published results on Notch signaling and EMT- or CSC-driven drug resistance. Moreover, other drug resistance-related mechanisms are examined such as the involvement of the Notch pathway in drug efflux and tumor microenvironment. Collectively, there is a long way to go before every facet will be fully understood; nevertheless, some small pieces are falling neatly into place. Overall, the main aim of this review is to provide strong evidence in support of Notch signaling inhibition as an effective strategy to evade or reverse resistance in female-specific cancers.

Identification of key genes associated with polycystic ovary syndrome (PCOS) and ovarian cancer using an integrated bioinformatics analysis

BACKGROUND

Accumulating evidence suggests a strong association between polycystic ovary syndrome (PCOS) and ovarian cancer (OC), but the potential molecular mechanism remains unclear. In this study, we identified previously unrecognized genes that are significantly correlated with PCOS and OC via bioinformatics.

MATERIALS AND METHODS

Multiple bioinformatic analyses, such as differential expression analysis, univariate Cox analysis, functional and pathway enrichment analysis, protein-protein interaction (PPI) network construction, survival analysis, and immune infiltration analysis, were utilized. We further evaluated the effect of OGN on FSHR expression via immunofluorescence.

RESULTS

TCGA-OC, GSE140082 (for OC) and GSE34526 (for PCOS) datasets were downloaded. Twelve genes, including RNF144B, LPAR3, CRISPLD2, JCHAIN, OR7E14P, IL27RA, PTPRD, STAT1, NR4A1, OGN, GALNT6 and CXCL11, were identified as signature genes. Drug sensitivity analysis showed that OGN might represent a hub gene in the progression of PCOS and OC. Experimental analysis found that OGN could increase FSHR expression, indicating that OGN could regulate the hormonal response in PCOS and OC. Furthermore, correlation analysis indicated that OGN function might be closely related to m6A and ferroptosis.

CONCLUSIONS

Our study identified a 12-gene signature that might be involved in the prognostic significance of OC. Furthermore, the hub gene OGN represent a significant gene involved in OC and PCOS progression by regulating the hormonal response.

Overview of follicle stimulating hormone and its receptors in reproduction and in stem cells and cancer stem cells

Follicle stimulating hormone (FSH) and its receptor (FSHR) have been reported to be responsible for several physiological functions and cancers. The responsiveness of stem cells and cancer stem cells towards the FSH-FSHR system make the function of FSH and its receptors more interesting in the context of cancer biology. This review is comprised of comprehensive information on FSH-FSHR signaling in normal physiology, gonadal stem cells, cancer cells, and potential options of utilizing FSH-FSHR system as an anti-cancer therapeutic target.

Mixtures of persistent organic pollutants increase ovarian granulosa tumor cell line migration and spheroid invasion by upregulating MMP2 expression and activity via IGF1R

Granulosa cell tumors (GCT) of the ovary have a good prognosis. Recurrence tends to be late; however, > 66 % of patients with recurrent GCT die from the disease. Most recurrences are abdominopelvic, although distant metastases have been documented. Here, we tested the hypothesis that a mixture of persistent endocrine-disrupting chemicals (EDCs) stimulates the invasion of GCT cells. We selected perfluorooctanoate (PFOA, 2 ng/mL), perfluorooctanesulfonate (PFOS, 8 ng/mL), 2,2-dichlorodiphenyldichloroethylene (p,p'-DDE, 1 ng/mL), polychlorinated biphenyl 153 (PCB153, 100 pg/mL), and hexachlorobenzene (HCB, 50 pg/mL), which have the highest measured concentrations in follicular fluid of women undergoing treatment with assisted reproductive technology. The human GCT cell lines COV434 and KGN have been used as in vitro models of juvenile (JGCT) and adult (AGCT) GCT subtypes, respectively. Cells were treated with a mixture of the test compounds for 15 min prior to analysis of protein phosphorylation; for 4 h prior to analysis in a circular chemorepellent-induced defect assay; for 6 h prior to analysis of matrix metalloproteinase 2 (MMP2) activity; for 24 h prior to analysis of migration, invasion, and gene expression; and for 48 h prior to analysis of protein expression. First, we showed that KGN cells migrated and exhibited invasive behavior. By contrast, COV434 cells lacked migration and invasion potential. Moreover, expression of mesenchymal genes and the gene encoding MMP2 was higher in KGN cells, and that of epithelial genes lower, than that in COV434 cells. Treatment of KGN cells with the EDC mixture stimulated cell migration, invasion, and lymphatic dissemination. The results suggest that the role of the EDC mixture in AGCT invasion is not related to changes in expression of epithelial and mesenchymal genes; rather, it is related to increased expression and activity of MMP2. Additionally, silencing insulin-like growth factor 1 (IGF1R) in AGCT abolished the stimulatory effect of the EDC mixture on KGN spheroid invasion. These results demonstrate that the EDC mixture increased KGN spheroid invasion by stimulating expression and activity of MMP2 via IGF1R.

FSH Levels Are Related to E-cadherin Expression and Subcellular Location in Nonfunctioning Pituitary Tumors

CONTEXT

Gonadotroph pituitary neuroendocrine tumors (PitNETs) can express follicle-stimulating hormone (FSH) and luteinizing hormone (LH) or be hormone negative, but they rarely secrete hormones. During tumor development, epithelial cells develop a mesenchymal phenotype. This process is characterized by decreased membranous E-cadherin and translocation of E-cadherin to the nucleus. Estrogen receptors (ERs) regulate both E-cadherin and FSH expression and secretion. Whether the hormone status of patients with gonadotroph PitNETs is regulated by epithelial-to-mesenchymal transition (EMT) and ERs is unknown.

OBJECTIVES

To study the effect of EMT on hormone expression in gonadotroph nonfunctioning (NF)-PitNETs.

DESIGN

Molecular and clinical analyses of 105 gonadotroph PitNETs. Immunohistochemical studies and real-time quantitative polymerase chain reaction were performed for FSH, LH, E-cadherin, and ERα. Further analyses included blood samples, clinical data, and radiological images.

SETTING

All patients were operated on in the same tertiary referral center.

RESULTS

NF-PitNET with high FSH expression had decreased immunohistochemical staining for membranous E-cadherin (P < .0001) and increased staining for nuclear E-cadherin (P < .0001). Furthermore, high FSH expression was associated with increased ERα staining (P = .0002) and ERα mRNA (P = .0039). Circulating levels of plasma-FSH (P-FSH) correlated with FSH staining in gonadotroph NF-PitNET (P = .0025). Tumor size and invasiveness was not related to FSH staining, E-cadherin, or ERα. LH expression was not associated with E-cadherin or ERα.

CONCLUSION

In gonadotroph PitNETs, FSH staining is related to E-cadherin, ERα expression, and circulating levels of P-FSH. There was no association between FSH staining and invasiveness. The clinical significance of these findings will be investigated in ongoing prospective studies.

Understanding Keloid Pathobiology From a Quasi-Neoplastic Perspective: Less of a Scar and More of a Chronic Inflammatory Disease With Cancer-Like Tendencies

Keloids are considered as benign fibroproliferative skin tumors growing beyond the site of the original dermal injury. Although traditionally viewed as a form of skin scarring, keloids display many cancer-like characteristics such as progressive uncontrolled growth, lack of spontaneous regression and extremely high rates of recurrence. Phenotypically, keloids are consistent with non-malignant dermal tumors that are due to the excessive overproduction of collagen which never metastasize. Within the remit of keloid pathobiology, there is increasing evidence for the various interplay of neoplastic-promoting and suppressing factors, which may explain its aggressive clinical behavior. Amongst the most compelling parallels between keloids and cancer are their shared cellular bioenergetics, epigenetic methylation profiles and epithelial-to-mesenchymal transition amongst other disease biological (genotypic and phenotypic) behaviors. This review explores the quasi-neoplastic or cancer-like properties of keloids and highlights areas for future study.

Ddx4+ Oogonial Stem Cells in Postmenopausal Women's Ovaries: A Controversial, Undefined Role

Recent studies support the existence of oogonial stem cells (OSCs) in the ovarian cortex of different mammals, including women.These cells are characterized by small size, membrane expression of DEAD(Asp-Glu-Ala-Asp)-box polypeptide-4 (Ddx4), and stemness properties (such as self-renewal and clonal expansion) as well as the ability to differentiate in vitro into oocyte-like cells. However, the discovery of OSCs contrasts with the popular theory that there is a numerically defined oocyte pool for female fertility which undergoes exhaustion with menopause. Indeed, in the ovarian cortex of postmenopausal women OSCs have been detected that possess both viability and capability to differentiate into oocytes, which is similar to those observed in younger patients. The pathophysiological role of this cell population in aged women is still debated since OSCs, under appropriate stimuli, differentiate into somatic cells, and the occurrence of Ddx4⁺ cells in ovarian tumor samples also suggests their potential involvement in carcinogenesis. Although further investigation into these observations is needed to clarify OSC function in ovary physiology, clinical investigators and researchers studying female infertility are presently focusing on OSCs as a novel opportunity to restore ovarian reserve in both young women undergoing early ovarian failure and cancer survivors experiencing iatrogenic menopause.

FSH Beyond Fertility

The traditional view of follicle-stimulating hormone (FSH) as a reproductive hormone is changing. It has been shown that FSH receptors (FSHRs) are expressed in various extra-gonadal tissues and mediate the biological effects of FSH at those sites. Molecular, animal, epidemiologic, and clinical data suggest that elevated serum FSH may play a significant role in the evolution of bone loss and obesity, as well as contributing to cardiovascular and cancer risk. This review summarizes recent data on FSH action beyond reproduction.

Heterodimer formation by Oct4 and Smad3 differentially regulates epithelial-to-mesenchymal transition-associated factors in breast cancer progression

The multifunctional cytokine TGF-β crucially participates in breast cancer (BCa) metastasis and works differently in the disease stages, thus contributing in BCa progression. We address connections between TGF-β and the stem cell-related transcription factor (TF) Oct4 in BCa. In 147 BCa patients with infiltrating duct carcinoma, we identified a significantly higher number of cases with both moderate/high Oct4 expression and high TGF-β in late stages compared to early stages of the disease. In vitro studies showed that TGF-β elevated Oct4 expression, which in turn, regulated Epithelial-to-Mesenchymal transition (EMT)-regulatory gene (Snail and Slug) expression, migratory ability, chemotactic invasiveness and extracellular matrix (ECM) degradation potential of BCa cells. Putative binding sites for Oct4 on the snail, slug and cxcl13 promoters and for Smad3 on the snail and slug promoters were identified. Promoter activities of snail and slug were greater in dual-treated cells than only TGF-β-treated or Oct4-overexpressing cells. CXCL13 mRNA fold changes, however, were low in cells induced with TGF-β, compared to dual-treated or Oct4-overexpressing cells. Our co-IP studies confirmed that Oct4 and Smad3 form heterodimers that recognize specific promoter sequences to promote Snail and Slug expression, but which in turn, indirectly inhibits Smad3-mediated repression of CXCL13 expression, allowing Oct4 to act as a positive TF for CXCL13. Taken together, these data suggest that TGF-β signaling and Oct4 cooperate to induce expression of EMT-related genes Snail, Slug and CXCL13, which accelerates disease progression, particularly in the late stages, and may indicate a poor prognosis for BCa patients.

C1GALT1 Seems to Promote In Vitro Disease Progression in Ovarian Cancer

OBJECTIVE

Aberrant glycosylation affects many cellular properties in cancers. The core 1 β1,3-galactosyltransferase (C1GALT1), an enzyme that controls the formation of mucin-type O-glycans, has been reported to regulate hepatocellular and mammary carcinogenesis. This study aimed to explore the role of C1GALT1 in ovarian cancer.

METHODS

C1GALT1 expression was assessed in a public database based on microarray data from 1287 ovarian cancer patients and ovarian cancerous tissues. Lectin blotting and flow cytometry analysis were conducted to detect changes in O-glycans on ovarian cancer cells. Effects of C1GALT1 on cell growth, migration, and sphere formation were analyzed in C1GALT1 knockdown or overexpressing ovarian cancer cells in vitro. Expression of cancer stemness-related genes was analyzed by quantitative reverse transcription polymerase chain reaction.

RESULTS

High C1GALT1 expression shows a trend toward association with poor survival in ovarian cancer patients. C1GALT1 modifies O-glycan expression on surfaces and glycoproteins of ovarian cancer cells. Knockdown of C1GALT1 decreased cell growth, migration, and sphere formation of ES-2 and OVTW59-p4 cells. Conversely, overexpression of C1GALT1 promoted such malignant properties of SKOV3 cells. Furthermore, C1GALT1 regulated the expression of several cancer stemness-related genes, including CD133, CD24, Oct4, Nanog, and SNAI2, in ovarian cancer cells.

CONCLUSIONS

C1GALT1 modifies O-glycan expression and enhances malignant behaviors in ovarian cancer cells, suggesting that C1GALT1 plays a role in the pathogenesis of ovarian cancer and targeting C1GALT1 could be a promising approach for ovarian cancer therapy.

Detection and analysis of circulating large intergenic non-coding RNA regulator of reprogramming in plasma for breast cancer

Background

Previous studies have indicated that large intergenic non‐coding RNA regulator of reprogramming (lincRNA‐ROR) plays an important role in regulating tumor carcinogenesis and metastasis; however, whether circulating lincRNA‐ROR could function as a potential biomarker for breast cancer (BC) diagnosis and monitoring is unknown. This study was conducted to investigate circulating lincRNA‐ROR in plasma as a potential biomarker for BC diagnosis and monitoring.

Methods

We performed reverse transcription‐quantitative‐PCR to examine lincRNA‐ROR expression levels in cell lines, 24 pairs of BC tissue samples, and 94 plasma samples from BC patients. Potential correlations between plasma lincRNA‐ROR levels and clinicopathological characteristics were analyzed. A receiver operating characteristic curve was calculated to evaluate the diagnostic values for BC. Pearson correlation analysis of lincRNA‐ROR in plasma samples and the corresponding tissues of the same patients was performed to explore tumor monitoring values.

Results

LincRNA‐ROR expression was significantly increased in BC cell lines, tissues, and plasma (all P < 0.01). Plasma lincRNA‐ROR levels were associated with estrogen receptors (P = 0.042) and lymph node metastasis (P = 0.046). The area under the receiver operating characteristic curve of plasma lincRNA‐ROR was 0.844 (sensitivity 80.0%, specificity 56.7%), which was higher than carcinoembryonic and carbohydrate antigen 15‐3 values. Moreover, plasma lincRNA‐ROR levels were decreased in postoperative compared to preoperative samples (P < 0.0001). Plasma lincRNA‐ROR levels moderately correlated with the corresponding tissue level in the same patients (r² = 0.638, P < 0.0001).

Conclusion

Plasma lincRNA‐ROR may be a potential biomarker for BC diagnosis and a dynamic monitor.

ANGPTL4 mediates the protective role of PPARγ activators in the pathogenesis of preeclampsia

Peroxisome proliferator-activated receptor γ (PPARγ) has been shown to be a therapeutic target for preeclampsia (PE). Angiopoietin-like protein 4 (ANGPTL4) is a multifunctional secretory protein involved in regulating lipid metabolism and angiogenesis in various tissues. However, the expression of PPARγ and ANGPTL4 and their interaction in PE remain elusive. Here we showed that PPARγ agonist rosiglitazone upregulated the expression and secretion of ANGPTL4 in a dose-dependent manner in HTR8/SVneo cells, human umbilical vein endothelial cells (HUVECs) and placental explants. More importantly, we confirmed that the PPARγ/retinoid X receptor α heterodimer specifically binds to the ANGPTL4 promoter region and enhances its transcriptional activity. In addition, the levels of ANGPTL4 and PPARγ activators in the serum and their expression in placental tissues were significantly reduced in preeclamptic patients compared with normal pregnant subjects. Furthermore, functional studies demonstrated that ANGPTL4 mediates the facilitative effects of the PPARγ agonist on the survival, proliferation, migration and invasion of HTR8/SVneo cells, placental explants outgrowth and angiogenesis in HUVECs. Taken together, our results suggest that ANGPTL4 is a potential target gene for PPARγ and mediates the protective role of PPARγ activators in the pathogenesis of PE.

ING5 activity in self-renewal of glioblastoma stem cells via calcium and follicle stimulating hormone pathways

Stem cell-like brain tumor initiating cells (BTICs) cause recurrence of glioblastomas, with BTIC 'stemness' affected by epigenetic mechanisms. The ING family of epigenetic regulators (ING1-5) function by targeting histone acetyltransferase (HAT) or histone deacetylase complexes to the H3K4me3 mark to alter histone acetylation and subsequently, gene expression. Here we find that ectopic expression of ING5, the targeting subunit of HBO1, MOZ and MORF HAT complexes increases expression of the Oct4, Olig2 and Nestin stem cell markers, promotes self-renewal, prevents lineage differentiation and increases stem cell pools in BTIC populations. This activity requires the plant homeodomain region of ING5 that interacts specifically with the H3K4me3 mark. ING5 also enhances PI3K/AKT and MEK/ERK activity to sustain self-renewal of BTICs over serial passage of stem cell-like spheres. ING5 exerts these effects by activating transcription of calcium channel and follicle stimulating hormone pathway genes. In silico analyses of The Cancer Genome Atlas data suggest that ING5 is a positive regulator of BTIC stemness, whose expression negatively correlates with patient prognosis, especially in the Proneural and Classical subtypes, and in tumors with low SOX2 expression. These data suggest that altering histone acetylation status and signaling pathways induced by ING5 may provide useful clinical strategies to target tumor resistance and recurrence in glioblastoma.

Long non-coding RNAs as novel biomarkers for breast cancer invasion and metastasis

Breast cancer (BC) is now the most common malignancy worldwide, with high prevalence and lethality among women. Invasion and metastasis are the major reasons for breast cancer-associated mortality. However, the underlying mechanism of invasion and metastasis has not been entirely elucidated. Long non-coding RNAs (lncRNAs) are a large class of non-coding transcripts that are >200 bases in length and cannot encode proteins. Evidence has indicated that lncRNAs regulate gene expression at the levels of epigenetic modification, transcription and post-transcription. In addition, they are involved in diverse tumor biological processes, including cell proliferation, apoptosis, invasion, metastasis and angiogenesis. The present review focuses on the recent progress of lncRNAs in breast cancer invasion and metastasis, aiming to provide novel strategies for the clinical prevention, diagnosis and treatment of breast cancer.

Cigarette smoke extract induces epithelial-mesenchymal transition of human bladder cancer T24 cells through activation of ERK1/2 pathway

Bladder cancer is a common genitourinary malignant disease worldwide. Abundant evidence has shown that cigarette smoke (CS) is a crucial risk factor for bladder cancer. Nevertheless, the mechanism underlying the relationship between cigarette smoking and bladder cancer remains unclear. In the present study, we investigated the effects of cigarette smoke extract (CSE) on mitogen-activated protein kinase (MAPK) pathway activation and EMT alterations in human bladder cancer T24 cells, and the preventive effect of extracellular regulated protein kinases 1 and 2 (ERK1/2) inhibitor U0126 was further examined. Our results illustrated that CSE exposure induced morphological change of human bladder cancer T24 cells, enhanced migratory and invasive capacities, reduced epithelial marker expression and elevated mesenchymal marker expression. Meanwhile, exposure of T24 cells to CSE resulted in activation of ERK1/2 pathway as well as activator protein 1 (AP-1) proteins. Interestingly, treatment with ERK1/2 inhibitor U0126 effectively abrogated CSE-triggered EMT and ERK1/2/AP-1 activation. These findings provide novel insight into the molecular mechanisms of CS-associated bladder cancer and may open up new avenues in the search for potential target of bladder cancer intervention.

The Role of Endocrine G Protein-Coupled Receptors in Ovarian Cancer Progression

Ovarian cancer is the seventh most common cancer in women and the most lethal gynecological cancer, causing over 151,000 deaths worldwide each year. Dysregulated production of endocrine hormones, known to have pluripotent effects on cell function through the activation of receptor signaling pathways, is believed to be a high-risk factor for ovarian cancer. An increasing body of evidence suggests that endocrine G protein-coupled receptors (GPCRs) are involved in the progression and metastasis of ovarian neoplasms. GPCRs are attractive drug targets because their activities are regulated by more than 25% of all drugs approved by the Food and Drug Administration. Therefore, understanding the role of endocrine GPCRs during ovarian cancer progression and metastasis will allow for the development of novel strategies to design effective chemotherapeutic drugs against malignant ovarian tumors. In this review, we address the signaling pathways and functional roles of several key endocrine GPCRs that are related to the cause, progression, and metastasis of ovarian cancer.

Characterization of adipose-derived stem cells from subcutaneous and visceral adipose tissues and their function in breast cancer cells

Adipose-derived stem cells are capable of differentiating into multiple cell types and thus considered useful for regenerative medicine. However, this differentiation feature seems to be associated with tumor initiation and metastasis raising safety concerns, which requires further investigation. In this study, we isolated adipose-derived stem cells from subcutaneous as well as from visceral adipose tissues of the same donor and systematically compared their features. Although being characteristic of mesenchymal stem cells, subcutaneous adipose-derived stem cells tend to be spindle form-like and are more able to home to cancer cells, whereas visceral adipose-derived stem cells incline to be “epithelial”-like and more competent to differentiate. Moreover, compared to subcutaneous adipose-derived stem cells, visceral adipose-derived stem cells are more capable of promoting proliferation, inducing the epithelial-to-mesenchymal transition, enhancing migration and invasion of breast cancer cells by cell-cell contact and by secreting interleukins such as IL-6 and IL-8. Importantly, ASCs affect the low malignant breast cancer cells MCF-7 more than the highly metastatic MDA-MB-231 cells. Induction of the epithelial-to-mesenchymal transition is mediated by the activation of multiple pathways especially the PI3K/AKT signaling in breast cancer cells. BCL6, an important player in B-cell lymphoma and breast cancer progression, is crucial for this transition. Finally, this transition fuels malignant properties of breast cancer cells and render them resistant to ATP competitive Polo-like kinase 1 inhibitors BI 2535 and BI 6727.

Relationship between Oct4 and colorectal cancer development and progression

Octamer-binding transcription factor 4 (Oct4), a member of the POU transcription factor family, is considered the key factor for maintaining self-renewal and pluripotency of embryonic stem cells. It is expressed not only in embryonic stem cells, germ cells and embryonic tumor cells but also in a variety of somatic cell tumors, and is closely related with the occurrence and development of malignant tumors. Recent studies have shown that Oct4 is the target gene of Wnt and transforming growth factor-β signaling pathways, and is involved in maintaining the survival of the colon cancer stem cells. The expression of Oct4 has a profound impact on the occurrence, recurrence, metastasis and prognosis of colorectal cancer. In this paper, we will review the relationship between Oct4 and colorectal cancer development and progression.

The emerging roles of Oct4 in tumor-initiating cells

Octamer-binding transcription factor 4 (Oct4), a homeodomain transcription factor, is well established as a master factor controlling the self-renewal and pluripotency of pluripotent stem cells. Also, a large body of research has documented the detection of Oct4 in tumor cells and tissues and has indicated its enrichment in a subpopulation of undifferentiated tumor-initiating cells (TICs) that critically account for tumor initiation, metastasis, and resistance to anticancer therapies. There is circumstantial evidence for low-level expression of Oct4 in cancer cells and TICs, and the participation of Oct4 in various TIC functions such as its self-renewal and survival, epithelial-mesenchymal transition (EMT) and metastasis, and drug resistance development is implicated from considerable Oct4 knockdown and overexpression-based studies. In a few studies, efforts have been made to identify Oct4 target genes in TICs of different sources. Based on such information, Oct4 in TICs appears to act via mechanisms quite distinct from those in pluripotent stem cells, and a main challenge for future studies is to unravel the molecular mechanisms of action of Oct4, particularly to address the question on how such low levels of Oct4 may exert its functions in TICs. Acquiring cells from their native microenvironment that are of high enough quantity and purity is the key to reliably analyze Oct4 functions and its target genes in TICs, and the information gained may greatly facilitate targeting and eradicating those cells.

Development of Follicle-Stimulating Hormone Receptor Binding Probes to Image Ovarian Xenografts

The Follicle-Stimulating Hormone Receptor (FSHR) is used as an imaging biomarker for the detection of ovarian cancer (OC). FSHR is highly expressed on ovarian tumors and involved with cancer development and metastatic signaling pathways. A decapeptide specific to the FSHR extracellular domain is synthesized and conjugated to fluorescent dyes to image OC cells in vitro and tumors xenograft model in vivo. The in vitro binding curve and the average number of FSHR per cell are obtained for OVCAR-3 cells by a high resolution flow cytometer. For the decapeptide, the measured EC50 was 160 μM and the average number of receptors per cell was 1.7 × 10⁷. The decapeptide molecular imaging probe reached a maximum tumor to muscle ratio five hours after intravenous injection and a dose-dependent plateau after 24-48 hours. These results indicate the potential application of a small molecular weight imaging probe specific to ovarian cancer through binding to FSHR. Based on these results, multimeric constructs are being developed to optimize binding to ovarian cells and tumors.