The nerve growth factor alters calreticulin translocation from the endoplasmic reticulum to the cell surface and its signaling pathway in epithelial ovarian cancer cells

Abstract

Abstract. Ovarian cancer is the seventh most common cancer among women worldwide, causing approximately 120,000 deaths every year. Immunotherapy, designed to boost the body's natural defenses against cancer, appears to be a promising option against ovarian cancer. Calreticulin (CRT) is an endoplasmic reticulum (ER) resident chaperone that, translocated to the cell membrane after ER stress, allows cancer cells to be recognized by the immune system. The nerve growth factor (NGF) is a pro-angiogenic molecule overexpressed in this cancer. In the present study, we aimed to determine weather NGF has an effect in CRT translocation induced by cytotoxic and ER stress. We treated A2780 ovarian cancer cells with NGF, thapsigargin (Tg), an ER stress inducer and mitoxantrone (Mtx), a chemotherapeutic drug; CRT subcellular localization was analyzed by immunofluorescence followed by confocal microscopy. In order to determine NGF effect on Mtx and Tg-induced CRT translocation from the ER to the cell membrane, cells were preincubated with NGF prior to Mtx or Tg treatment and CRT translocation to the cell surface was determined by flow cytometry. In addition, by western blot analyses, we evaluated proteins associated with the CRT translocation pathway, both in A2780 cells and human ovarian samples. We also measured NGF effect on cell apoptosis induced by Mtx. Our results indicate that Mtx and Tg, but not NGF, induce CRT translocation to the cell membrane. NGF, however, inhibited CRT translocation induced by Mtx, while it had no effect on Tg-induced CRT exposure. NGF also diminished cell death induced by Mtx. NGF effect on CRT translocation could have consequences in immunotherapy, potentially lessening the effectiveness of this type of treatment.

Glycoproteomics identifies HOMER3 as a potentially targetable biomarker triggered by hypoxia and glucose deprivation in bladder cancer

“…The scoring system significantly valued "low" or "null" expressions in healthy tissues, overexpression in bladder tumours and associations with poor prognosis. In addition, it favored proteins localized at the cell surface in cancer cells in opposition to other subcellular locations in healthy tissues, which is frequently observed in cancer [23,[34][35][36]. On the other hand, proteins present in lymphoid system intermediates and gametes were poorly scored, penalizing potential deleterious effects in immune and reproductive systems.…”

Signaling Pathways Related to Nerve Growth Factor and miRNAs in Epithelial Ovarian Cancer

“…Importantly, despite the pro-carcinogenic effects of CRT, when this protein is found in the cell surface it can induce an anti-immune response against cancer cells [58]. In human ovarian cancer cells, our research group found that mitoxantrone, a direct ER stress inducer, can trigger CRT translocation from the ER to the cell surface [30]. Previous studies have shown that ER stress is a necessary step for CRT transport to the cell surface, and concordantly, in EOC cells, CRT translocation was accompanied by activation of the UPR protein PERK and its substrate eIF2α [59].…”

“…The NGF/TRKA signaling pathway has also been linked to several transduction cascades that stimulate cancer progression, including VEGF production and secretion [26], the COX2/PGE2 inflammatory response [28], ADAM17 activity [29] and alterations on calreticulin (CRT) subcellular localization [30]. All the molecules mentioned above have a role in the development or progression of ovarian cancer by altering processes such as inflammation, angiogenesis, immune evasion, survival and metastasis.…”

“…CRT protein levels are elevated in different cancer tissues, including EOC [37,65], and while this increase could be associated with an adaptation to ER stress, CRT expression has also been linked to proliferation, metastasis, invasion and angiogenesis [56]. Moreover, in EOC cells, NGF induces an increase of CRT levels, which could be associated with the acquirement of carcinogenic properties [30,57].…”

“…Interestingly, several reports show that NGF can inhibit the effects of ER stress, which could hinder cells' ability to translocate CRT from the ER to the cell surface [60][61][62]. Indeed, when A2780 cells were incubated with both NGF and mitoxantrone, CRT levels on the cell surface were diminished compared to cells stimulated with mitoxantrone alone [30]. Therefore, an anticancer immune therapy based on drugs that induce CRT translocation from the ER to the cell surface could have limited efficiency in ovarian cancer patients, since NGF levels inhibit CRT translocation.…”