Oestrogen induces c-Ha-ras expression in the fibroblasts derived from human uterine endometrium

Cancer-Associated Fibroblasts in Conversation with Tumor Cells in Endometrial Cancers: A Partner in Crime

A tumor cell carrying characteristic genomic alteration(s) exists within its host’s microenvironment. The tumor microenvironment (TME) renders holistic support to the tumor via cross-talk between tumor cells and three components of TME, immune components, vascular components, and fibroblast components. The tempero-spatial interaction of tumor cells with its microenvironment is the deterministic factor for tumor growth, progression, resistance to therapy, and its outcome in clinics. TME (1) facilitates proliferation, and the ensuing metastasis-associated phenotypes, (2) perturbs immune surveillance and supports tumor cells in their effort to evade immune recognition, and (3) actively participates in developing drug-induced resistance in cancer cells. Cancer-Associated Fibroblast (CAF) is a unique component of TME. CAF is the host mesenchyme immediately surrounding the tumor cells in solid tumors. It facilitates tumor growth and progression and participates in developing drug resistance in tumor cells by playing a critical role in all the ways mentioned above. The clinical outcome of a disease is thus critically contributed to by the CAF component of TME. Although CAFs have been identified historically, the functional relevance of CAF-tumor cell cross-talk and their influence on angiogenic and immune-components of TME are yet to be characterized in solid tumors, especially in endometrial cancers. Currently, the standard of care for the treatment of endometrial cancers is primarily guided by therapies directed towards the disease’s tumor compartment and immune compartments. Unfortunately, in the current state of therapies, a complete response (CR) to the therapy is still limited despite a more commonly achieved partial response (PR) and stable disease (SD) in patients. Acknowledging the limitations of the current sets of therapies based on only the tumor and immune compartments of the disease, we sought to put forward this review based on the importance of the cross-talk between CAF of the tumor microenvironment and tumor cells. The premise of the review is to recognize the critical role of CAF in disease progression. This manuscript presents a systemic review of the role of CAF in endometrial cancers. We critically interrogated the active involvement of CAF in the tumor compartment of endometrial cancers. Here we present the functional characteristics of CAF in the context of endometrial cancers. We review (1) the characteristics of CAF, (2) their evolution from being anti-tumor to pro-tumor, (3) their involvement in regulating growth and several metastasis-associated phenotypes of tumor cells, (4) their participation in perturbing immune defense and evading immune surveillance, and (5) their role in mediating drug resistance via tumor-CAF cross-talk with particular reference to endometrial cancers. We interrogate the functional characteristics of CAF in the light of its dialogue with tumor cells and other components of TME towards developing a CAF-based strategy for precision therapy to supplement tumor-based therapy. The purpose of the review is to present a new vision and initiate a thought process which recognizes the importance of CAF in a tumor, thereby resulting in a novel approach to the design and management of the disease in endometrial cancers.

Ovarian steroids regulate the expression of basic fibroblast growth factor and its mRNA in fibroblasts derived from uterine endometrium

The role of stromal cells in basic fibroblast growth factor (FGF) supply for endometrial neovascularization during the menstrual cycle was investigated. The concentrations of intracellular and secreted FGF, and FGF mRNA expression were determined in fibroblasts derived from uterine endometrium as a substitute for stromal cells. The influence of sex steroids on protein and mRNA expression was investigated. The concentration of FGF and its mRNA expression in the fibroblasts was significantly increased by oestradiol, and these increased concentrations were diminished by progesterone. It is suggested that oestrogen stimulates FGF secretion from the stromal cells, an effect which is inhibited by progesterone. Therefore, endometrial neovascularization might be partially regulated by stromal-derived FGF under the influence of sex steroids, through a paracrine cell-to-cell interaction.

Sex steroids regulate the expression of plasminogen activator inhibitor-1 and its mRNA in fibroblasts derived from uterine endometrium

In order to clarify a role of stromal cells in sex steroidal neovascularization, plasminogen activator inhibitor (PAI)-1 [an inhibitor of tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA)] and its messenger ribonucleic acid (mRNA) were analysed in fibroblasts derived from uterine endometrium as a model for endometrial stromal cells under the influence of sex steroids. The determinations were carried out by an enzyme-linked immunosorbent assay (ELISA) and reverse transcription-polymerase chain reaction-Southern blotting, respectively. In the fibroblasts, either estradiol or progestogens (progesterone, medroxy progesterone acetate or 17 alpha-hydroxyprogesterone) induced expressions of PAI-1 and its mRNA, and their combination further increased their expression by approximately twofold. PAI-1 from endometrial stromal cells under the influence of sex steroids might contribute to endometrial neovascularization through its effect on endothelial cells in endometrial vessels.