Melatonin protects against excessive autophagy-induced mitochondrial and ovarian reserve function deficiency though ERK signaling pathway in Chinese hamster ovary (CHO) cells

Excessive autophagy-induced follicular atresia of ovarian granulosa cells might be one of the pathogenesis of Premature Ovarian Insufficiency (POI), and melatonin (MT) exerted many beneficial effects on mitochondria. However, there was little report regarding the beneficial effects of MT on excessive autophagy-induced mitochondrial and ovarian reserve function deficiency, and the mechanisms have not been clearly identified. Autophagy played a protective role in cells survival, however, high level of autophagy could lead to cell death. In this report, firstly, Chinese hamster ovary cell damage model stably expressing EGFP-LC3 was established. Next, we systematically investigated the protective effects of MT on mitochondrial and ovarian reserve function and molecular mechanisms using this cell damage model. Our results revealed that 10^-9 M MT not only protected against the decline of anti-mullerian hormone (AMH) expression induced by excessive autophagy, but also rescued excessive autophagy-induced impairment of mitochondrial expression and mitochondrial membrane potential. Furthermore, MT protected against excessive autophagy-induced decrease of nucleus-encoded proteins including SDHA and mitofilin, and mitochondrial dynamic-related proteins including OPA1, MFN2, and DRP1. MT also decreased mitochondrial oxidative stress, increased antioxidant enzyme superoxide dismutase 2 (SOD2) expression and ameliorated the G2/M cell cycle arrest induced by excessive autophagy. Finally, MT inhibited excessive autophagy-induced activation of extracellular signal regulated kinase (ERK) signaling pathway. In conclusion, our study showed that MT rescued impairment of mitochondrial and ovarian reserve function, and production of mitochondrial ROS and cell cycle arrest induced by excessive autophagy through down-regulated ERK pathway, implying the potential therapeutic drug target for POI.

[A phase Ⅰ dose-escalating trial of pegylated liposomal doxorubicin in combination with cyclophosphamide, vincristine and prednisone for aggressive non-Hodgkin lymphoma]

Objective: To explore the maximum tolerated dose of pegylated liposomal doxorubicin (PLD) in combination with cyclophosphamide, vincristine and prednisone as a modified CHOP regimen for aggressive non-Hodgkin lymphoma. Methods: Patients with newly diagnosed aggressive non-Hodgkin lymphoma were eligible for this trial. PLD was administered in cycle 1 and categorized into 4 dose level (30 mg/m², 35 mg/m², 40 mg/m², 45 mg/m² D1) according to a 3 + 3 approach for dose-escalation. Doxorubin was used in cycles 2-6. In this combination regimen, the doses of cyclophosphamide (750 mg/m² D1), vincristine (1.4 mg/m² D1, maximum dose of 2 mg) and prednisone (100 mg D1-5) were fixed. Toxicities of cycle 1 were documented. Results: Totally, 21 patients were enrolled in this trial. Among them, 15 patients had T-cell lymphoma and 6 had B-cell lymphoma. When the dose of PLD was escalated to the level of 45 mg/m², 2 of 3 patients developed grade 3 mucositis, which met the criteria of dose-limiting toxicity. Therefore, the dose was de-escalated for one level. At the level of 40 mg/m², only one among 12 patients had pneumonia and grade 4 neutropenia. In all dose levels, the grade 3/4 toxicities observed were neutropenia (13 cases, 61.9% ), mucositis (2 cases, 9.5% ), thrombocytopenia (1 case, 4.8%) and pneumonia (1 case, 4.8%). Conclusion: When combined with cyclophosphamide, vincristine and prednisone as a combination regimen, the maximum tolerated dose of PLD was 40 mg/m².