An immature inhibin-α-expressing subpopulation of ovarian clear cell carcinoma cells is related to an unfavorable prognosis

From clinical management to personalized medicine: novel therapeutic approaches for ovarian clear cell cancer

Ovarian clear-cell cancer is a rare subtype of epithelial ovarian cancer with unique clinical and biological features. Despite optimal cytoreductive surgery and platinum-based chemotherapy being the standard of care, most patients experience drug resistance and a poor prognosis. Therefore, novel therapeutic approaches have been developed, including immune checkpoint blockade, angiogenesis-targeted therapy, ARID1A synthetic lethal interactions, targeting hepatocyte nuclear factor 1β, and ferroptosis. Refining predictive biomarkers can lead to more personalized medicine, identifying patients who would benefit from chemotherapy, targeted therapy, or immunotherapy. Collaboration between academic research groups is crucial for developing prognostic outcomes and conducting clinical trials to advance treatment for ovarian clear-cell cancer. Immediate progress is essential, and research efforts should prioritize the development of more effective therapeutic strategies to benefit all patients.

Tumor heterogeneity from the viewpoint of pathologists

Morphological and functional heterogeneity are found in tumors, with the latter reflecting the different levels of resistance against antitumor therapies. In a therapy-resistant subpopulation, the expression levels of differentiation markers decrease, and those of immature markers increase. In addition, this subpopulation expresses genes involved in drug metabolism, such as aldehyde dehydrogenase 1A1 (ALDH1A1). Because of their similarity to stem cells, cells in the latter therapy-resistant subpopulation are called cancer stem cells (CSCs). Like normal stem cells, CSCs were originally thought not to arise from non-CSCs, but this hierarchical model is too simple. It is now believed that CSCs are generated from non-CSCs. The plasticity of tumor phenotypes between CSCs and non-CSCs causes difficulty in completely curing tumors. In this review, focusing on ALDH1A1 as a marker for CSCs or immature tumor cells, the dynamics of ALDH1A1-expressing tumor cells and their regulatory mechanisms are described, and the plausible regulatory mechanisms of plasticity of ALDH1A1 expression phenotype are discussed. Genetic mutations are a significant factor for tumorigenesis, but non-mutational epigenetic reprogramming factors yielding tumor heterogeneity are also crucial in determining tumor characteristics. Factors influencing non-mutational epigenetic reprogramming in tumors are also discussed.

Evolving roles of activins and inhibins in ovarian cancer pathophysiology

Activins and inhibins are unique members of the transforming growth factor-β (TGFβ) family of growth factors, with the ability to exert autocrine, endocrine, and paracrine effects in a wide range of complex physiologic and pathologic processes. Although first isolated within the pituitary, emerging evidence suggests broader influence beyond reproductive development and function. Known roles of activin and inhibin in angiogenesis and immunity along with correlations between gene expression and cancer prognosis suggest potential roles in tumorigenesis. Here, we present a review of the current understanding of the biological role of activins and inhibins as it relates to ovarian cancers, summarizing the underlying signaling mechanisms and physiologic influence, followed by detailing their roles in cancer progression, diagnosis, and treatment.

Tumor cell plasticity in endometrioid carcinoma is regulated by neuronal membrane glycoprotein M6-b

Tumor cell plasticity and tumor heterogeneity are involved in therapy resistance. Cancer stem cells (CSCs) refer to tumor cells that have the ability to self-renew, and generate the diverse cells that comprise the tumor and complicate tumor heterogeneity. In recent years, CSCs have been reported to emerge from non-CSCs, which is known as tumor cell plasticity; however, the mechanism has not been fully elucidated. The present study investigated tumor cell plasticity from the viewpoint of aldehyde dehydrogenase 1 family member A1 (ALDH1A1) activity, which is one of the markers of CSCs. In the endometrioid carcinoma cell line HEC-1B, the ALDH1A1-low population spontaneously yielded an ALDH1A1-high population, mimicking tumor cell plasticity, and it was revealed that the mixture of the ALDH1A1-high population with the ALDH1A1-low population sometimes accelerated the transition from an ALDH1A1-low to ALDH1A1-high population. Two distinct HEC-1B sublines were established. One of the two sublines accelerated such a transition and the other did not show such acceleration. In the former subline, the effect of the ALDH1A1-high population was abolished when the direct cell-cell contact between ALDH1A1-high and ALDH1A1-low populations was inhibited. By comparing the two sublines, the neuronal membrane glycoprotein M6-b (GPM6B) was identified as the candidate mediating tumor cell plasticity. GPM6B was expressed in the border of ALDH1A1-expressing tumor cells and non-expressing tumor cells in clinical samples of EC. Notably, knockout of GPM6B decreased ALDH1A1 expression, whereas its overexpression increased the expression of ALDH1A1, suggesting that GPM6B mediated the induction of ALDH1A1 and the plasticity of CSCs.

Low expression of INHB co-receptor TGFBR3 in connection with metastasis and immune infiltration in lung adenocarcinoma

OBJECTIVE

Inhibin B (INHB) is one of the TGF-β superfamily member, consisting of α (INHA) and βB (INHBB) subunits. Studies have found that TGF-β receptor 3 (TGFBR3) binds to a convex α subunit on the surface of INHB, and enhances the binding affinity of activin receptor type-2 (ACVR2A/B) to INHβ subunit. This study tried to evaluate the roles of INHB subunits and its receptors (INHA, ACVR2A, ACVR2B, INHBB, TGFBR3) as prognostic biomarkers and therapeutic targets for the effective treatment of lung adenocarcinoma (LUAD).

METHODS

We analyzed INHB subunits and its receptors' expression and the influence of LUAD from Oncomine, GEPIA, HCMDB, CancerSEA, TIMER databases and so on. Then, 41 cases of cancer tissue and 41 cases of adjacent epithelium were detected in LUAD patients by immunohistochemistry.

RESULTS

INHA, ACVR2A, ACVR2B, INHBB were up-regulated while TGFBR3 was down-regulated in LUAD. INHA, ACVR2A and TGFBR3 were found to be strongly associated with high-grade malignancies and advanced TNM, only TGFBR3 expression was negatively correlated with LUAD metastasis probably mainly through cell adhesion molecules and the PI3K-Akt signaling pathway, univariate and multivariate analysis suggested that overall survival was lower in LUAD cases with low TGFBR3 levels. Further analysis revealed that low TGFBR3 expression was related to reduced infiltration of immune cells into the LUAD, promoting metastasis of LUAD cells. TGFBR3 expression negatively correlates with lymphatic metastasis and clinical stage in patients with LUAD.

CONCLUSION

TGFBR3 could be a potential new metastatic biomarker for LUAD, with potential application as a prognostic marker and for immunotherapy of LUAD.