Molecular profiling of estrogen receptor α and progesterone receptor transcript variants in endometrial cancer

A novel alternative splicing-based prediction model for uteri corpus endometrial carcinoma

Alternative splicing (AS) is crucial a mechanism by which the complexity of mammalian and viral proteom increased overwhelmingly. There lacks systematic and comprehensive analysis of the prognostic significance of AS profiling landscape for uteri corpus endometrial carcinoma (UCEC). In this study, univariate and multivariate Cox regression analyses were conducted to identify candidate survival-associated AS events curated from SpliceSeq for the construction of prognostic index (PI) models. A correlation network between splicing factor-related AS events and significant survival-associated AS events were constructed using Cytoscape 3.5. As consequence, 28281 AS events from 8137 genes were detected from 506 UCEC patients, including 2630 survival-associated AS events. Kaplan Meier survival analysis revealed that six of the seven PI models (AD, AP, AT, ME, RI and ALL) exhibited good performance in stratifying the prognosis of low risk and high risk group (P<0.05). Among the six PI models, PI-AT performed best with an area under curves (AUC) value of 0.758 from time-dependent receiver operating characteristic. Correlation network implicated potential regulatory mechanism of AS events in UCEC. PI models based on survival-associated AS events for UCEC in this study showed preferable prognosis-predicting ability and may be promising prognostic indicators for UCEC patients.

Summary: This is the first study to systematically investigate the prognostic value of AS in UCEC. Findings in the presents study supported the clinical potential of AS for UCEC and shed light on the potential AS-associated molecular basis of UCEC.

Dual targeting of estrogen receptor α and estrogen-related receptor α: a novel endocrine therapy for endometrial cancer

Background

Endometrial cancer (EC) is a hormone dependent carcinoma that may involve complex molecular mechanisms. Endocrine therapy by blocking the estrogen and estrogen receptor α (ERα) has been effective in breast cancer, while it is still controversial in EC. Recently, estrogen-related receptor α (ERRα) was proven to be another endocrine therapy target.

Methods

The anti-tumor effect of selective estrogen receptor modulators (SERMs) and XCT790 (XCT) used alone or in combination were evaluated in both of ERα-positive (ERα+) and ERα-negative (ERα-) EC cells. ERα and ERRα mRNA were tested by qPCR, while the protein was detected by Western blot. The proliferation was tested by MTS and cell cycle, apoptosis rate were analyzed by flow cytometry.

Results

A relatively high dose (10 μM) of tamoxifen (TAM) suppressed the expression of ERα and ERRα in two types of EC cells. However, 10 μM raloxifene (RAL) exhibited no effect on ERα and ERRα, while 10 μM XCT down regulated ERRα specifically, but not ERα in all EC cells. When dual targeting on ERα and ERRα by combining TAM with XCT, the proliferation inhibitory effect and apoptosis reached the strongest in all EC cells (P<0.05). Moreover, the inhibitory effect of proliferation was attributed significantly to the G0/G1 arrest (P<0.05). Interestingly, the apoptosis induced by combining TAM with XCT were obviously higher in ERα+ EC cells than ERα- EC cells (P<0.05).

Conclusion

Taken together, the results indicate that dual targeting on ERα and ERRα represents a better anti-tumor effect, which provides a novel endocrine based therapy strategy for EC.

Whole Genome Analysis and Prognostic Model Construction Based on Alternative Splicing Events in Endometrial Cancer

Objectives

A growing body of evidence has shown that aberrant alternative splicing (AS) is closely related to the occurrence and development of cancer. However, prior studies mainly have concentrated on a few genes that exhibit aberrant AS. This study aimed to determine AS events through whole genome analysis and construct a prognostic model of endometrial cancer (EC).

Methods

We downloaded gene expression RNAseq data from UCSC Xena, and seven types of AS events from TCGA SpliceSeq. Univariate Cox regression was employed to analyze the prognostic-related alternative splicing events (PASEs) and splicing factors; multivariate Cox regression was conducted to analyze the effect of risk score (All) and clinicopathological parameters on EC prognosis. An underlying interaction network of PASEs of EC was constructed by Cytoscape Reactome FI, GO, and KEGG pathway enrichment was performed by DAVID. ROC curves and Kaplan-Meir analysis were used to assess the diagnostic value of prognostic model. The correlation between PASEs and splicing factors was analyzed by GraphPad Prism; then a network was constructed using Cytoscape.

Results

In total, 28,281 AS events in EC were identified, which consisted of 1166 PASEs. RNPS1, NEK2, and CTNNB1 were the hub genes in the network of the top 600 PASEs. The area under the curve (AUC) of risk score (All) reached 0.819. Risk score (All) together with FIGO stage, cancer status, and primary therapy outcome success was risk factors of the prognosis of EC patients. Splicing factors YBX1, HNRNPDL, and HNRNPA1 were significantly related to the overall survival (OS). The splicing network indicated that the expression of splicing factors was significantly correlated with percent-splice-in (PSI) value of PASEs.

Conclusion

We constructed a model for predicting the prognosis of EC patients based on PASEs using whole genome analysis of AS events and thereby provided a reliable theoretical basis for EC clinical prognosis evaluation.

N-terminal truncations in sex steroid receptors and rapid steroid actions

Sex steroid receptors act as ligand activated nuclear transcription factors throughout the body, including the brain. However, post-translational modification of these receptors can direct them to extranuclear sites, including the plasma membrane, where they are able to initiate rapid signaling. Because of the conserved domain structure of these receptors, alternative exon splicing can result in proteins with altered nuclear and extranuclear actions. Although much attention has focused on internal and C-terminal splice variants, both estrogen and androgen receptors undergo N-terminal truncations, as well. These truncated proteins not only influence the transcriptional activity of the full-length receptors, but also associate with caveolin and initiate signaling at the plasma membrane. Such actions may have important physiological consequences in neuronal, endothelial, and cancer signaling and cell survival.

Clinical effects of autologous cytokine-induced killer cell-based immunotherapy in the treatment of endometrial cancer: a case report and literature review

Endometrial cancer is the most prevalent gynecological malignancy in the USA, and its treatment involves surgery, chemotherapy, and radiotherapy. Cytokine-induced killer (CIK) cell-based treatments have shown antitumor activity against several solid tumors. However, to the best of our knowledge, there are no reports yet of CIK immunotherapy in the treatment of endometrial cancer, and consequently, little is known about its efficacy and safety. Here, we report a case of an endometrial cancer patient receiving a combination treatment with CIK cells immunotherapy and chemotherapy. Assessment for clinical features was carried out after every two cycles of CIK immunotherapy and chemotherapy. No severe toxicity was observed after infusion of CIK cells. After 4 cycles of treatment, the patient achieved complete response and showed elevated Karnofsky Performance Status scores with an overall survival time of 13.6 months. The combination therapy improved the quality of life and prolonged patient survival time, which suggested that CIK cell therapy might be a potentially beneficial option for endometrial cancer.

Endometrium and steroids, a pathologic overview

Normal endometrial function requires of cell proliferation and differentiation; therefore, disturbances in these processes could lead to pathological entities such as hyperplasia and endometrial adenocarcinoma, where cell proliferation is increased. The development of these pathologies is highly related to alterations in the levels and/or action of sexual steroids. In the present review, it has been analyzed how steroids, particularly estrogens, androgens and progestagens are involved in the etiopathogenesis of hyperplasia and endometrial endometrioid adenocarcinoma. The emphasis is given on pathological and pharmacological conditions that are presented as risk factors for endometrial pathologies, such as obesity, polycystic ovarian syndrome and hormone replacement postmenopausal women therapy, among others. Steroids alterations may promote changes at molecular level that enhance the development of hyperplasia and endometrioid cancer. In fact, there are solid data that indicate that estrogens stimulate cell-proliferation in this tissue; meanwhile, progestagens are able to stop cell proliferation and to increase differentiation. Nevertheless, the role of androgens is less clear, since there is contradictory information. It is most likely that the major contribution of steroids to the development of cell proliferation pathologies in endometria would be in early stages, where there is a high sensitivity to these molecules. This phenomenon is present even in stages previous to the occurrence of hyperplasia, like in the condition of polycystic ovarian syndrome, where the endometria have a greater sensitivity to steroids and high expression of cell cycle molecules. These abnormalities would contribute to the pathogenesis of hyperplasia and then in the progression to endometrioid adenocarcinoma.

Nomegestrol Acetate Suppresses Human Endometrial Cancer RL95-2 Cells Proliferation In Vitro and In Vivo Possibly Related to Upregulating Expression of SUFU and Wnt7a

Nomegestrol acetate (NOMAC) has been successfully used for the treatment of some gynecological disorders, and as a combined oral contraceptive with approval in many countries. In this study, we investigated the effects of NOMAC on human endometrial cancer cells in vitro and in vivo. The proliferation of human endometrial cancer cells (RL95-2 and KLE) were assessed using CCK-8 and EdU incorporation assays. Whole-genome cDNA microarray analysis was used to identify the effects of NOMAC on gene expression profiles in RL95-2 cells. RL95-2 xenograft nude mice were treated with NOMAC (50, 100, and 200 mg/kg) or medroxyprogesterone acetate (MPA; 100 and 200 mg/kg) for 28 consecutive days. The results showed that NOMAC significantly inhibited the growth of RL95-2 cells in a concentration-dependent manner, but not in KLE cells. Further investigation demonstrated that NOMAC produced a stronger inhibition of tumor growth (inhibition rates for 50, 100, and 200 mg/kg NOMAC were 24.74%, 47.04%, and 58.06%, respectively) than did MPA (inhibition rates for 100 and 200 mg/kg MPA were 41.06% and 27.01%, respectively) in the nude mice bearing the cell line of RL95-2. NOMAC altered the expression of several genes related to cancer cell proliferation, including SUFU and Wnt7a. The upregulation of SUFU and Wnt7a was confirmed using real-time quantitative polymerase chain reaction and Western blotting in RL95-2 cells and RL95-2 xenograft tumor tissues, but not in KLE cells. These data indicate that NOMAC can inhibit the proliferation of RL95-2 cell in vitro and suppress the growth of xenografts in the nude mice bearing the cell line of RL95-2 in vivo. This effect could be related to the upregulating expression of SUFU and Wnt7a.

Recurrent hormone-binding domain truncated ESR1 amplifications in primary endometrial cancers suggest their implication in hormone independent growth

The estrogen receptor alpha (ERα) is highly expressed in both endometrial and breast cancers, and represents the most prevalent therapeutic target in breast cancer. However, anti-estrogen therapy has not been shown to be effective in endometrial cancer. Recently it has been shown that hormone-binding domain alterations of ERα in breast cancer contribute to acquired resistance to anti-estrogen therapy. In analyses of genomic data from The Cancer Genome Atlas (TCGA), we observe that endometrial carcinomas manifest recurrent ESR1 gene amplifications that truncate the hormone-binding domain encoding region of ESR1 and are associated with reduced mRNA expression of exons encoding the hormone-binding domain. These findings support a role for hormone-binding alterations of ERα in primary endometrial cancer, with potentially important therapeutic implications.