NTSR1 glycosylation and MMP dependent cleavage generate three distinct forms of the protein

The melatonin-FTO-ATF4 signaling pathway protects granulosa cells from cisplatin-induced chemotherapeutic toxicity by suppressing ferroptosis

PURPOSE

In cisplatin-induced premature ovarian failure (POF) mice, granulosa cells showed a high level of ferroptosis. Previous research has indicated that the fat mass and obesity-associated protein/activating transcription factor 4 (FTO/ATF4) axis was involved in the regulation of ferroptosis. The purpose of this study was to explore the role of the FTO/ATF4 axis in cisplatin-induced ferroptosis in granulosa cell.

METHODS

The extent of ferroptosis was assessed by transmission electron microscopy (TEM) and ROS, GPX, GSH, and MDA assays. Western blotting was used to evaluate the protein expression levels of ferroptosis-related molecules. Ferroptosis activator and inhibitor were also used.

RESULTS

We found that ferroptosis increased in a concentration-dependent manner in cisplatin-induced injured granulosa cells, accompanied by the downregulation of FTO. In addition, gain- and loss-of-function studies showed that FTO affects ferroptosis in injured cells by regulating ATF4 expression. Ferrostatin-1 inhibited the effect of FTO downregulation on injured granulosa cells ferroptosis, and erastin reversed the protective effect of FTO on ferroptosis in injured granulosa cells. Finally, melatonin was used, and we found that melatonin reduced ferroptosis in cisplatin-induced injured granulosa cells by upregulating FTO expression.

CONCLUSION

Our study demonstrated that cisplatin induced granulosa cell ferroptosis by downregulating the expression of FTO. ATF4 was identified as a downstream target of FTO, and overexpression of ATF4 reversed the effects of decreased FTO on ferroptosis. Additionally, melatonin mitigates the cytotoxic effects of cisplatin by upregulating FTO expression. The melatonin-FTO-ATF4 signaling pathway plays a vital role in the treatment of cisplatin-induced POF.

Targeting the NTSR2/TrkB oncogenic pathway in chronic lymphocytic leukemia

Current therapies that target the B-cell receptor pathway or the inhibition of anti-apoptotic proteins do not prevent the progressive forms of chronic lymphocytic leukemia (CLL), have low long-term efficacy and are subject to therapeutic resistance. Deciphering the mechanisms of leukemic cell survival and searching for new specific targets therefore remain major challenges to improve the management of this disease. It was evidenced that NTSR2 (neurotensin receptor 2), through the recruitment of TRKB (tropomyosin related kinase B), induces survival pathways in leukemic B cells. We have investigated the therapeutic potential of this protein complex as a new target. The binding domain of NTSR2 and TRKB was identified and a peptide targeting the latter was designed. The peptide binds TRKB and efficiently decreases the interaction of the two proteins. It is also effectively internalized by CLL-B cells in which it notably affects Src family kinase signaling and anti-apoptotic proteins levels. It demonstrated a cytotoxic effect both in vitro on the MEC-1 cell line and ex vivo on a cohort of 30 CLL patients. Altogether, these results underline the therapeutic potential of the NTSR2/TRKB protein complex as a target in CLL and open new perspectives for the development of targeted therapies.