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Melatonin induces autophagy in neuroblastoma by alleviating Pak2‑mediated endoplasmic reticulum stress

Published on Friday, 02 January 2026

Abstract

Neuroblastoma (NB), the most common extracranial solid tumor in children, remains challenging to treat due to limited therapeutic efficacy and poor prognosis. Emerging evidence highlights the critical roles of endoplasmic reticulum (ER) stress and autophagy in cancer progression.

The present study investigated the therapeutic potential of melatonin in neuroblastoma and its underlying mechanisms. Using Neuro‑2a (N2a) cells, it demonstrated that melatonin alleviated ER stress by upregulating ER chaperones glucose‑regulated protein (GRP)78 and GRP94 and the pro‑apoptotic protein CHOP, while enhancing autophagic activity.

Western blotting revealed increased LC3‑II/I ratios, elevated autophagy‑related protein 5 and Beclin1 levels, and reduced p62 expression, indicating autophagy induction. Immunofluorescence and transmission electron microscopy confirmed the dose‑dependent accumulation of autophagosomes. ER stress inhibitor 4‑phenylbutyric acid attenuated melatonin‑induced autophagy, linking ER stress relief to autophagic activation.

Mechanistically, melatonin upregulated p21‑activated kinase 2 (Pak2), which suppressed mTOR phosphorylation and activated unc‑51‑like kinase 1, thereby modulating the AMP‑activated protein kinase (AMPK) pathway. Pak2 overexpression amplified melatonin's ER stress‑alleviating effects, whereas Pak2 knockdown or AMPK inhibition diminished its efficacy.

These findings established that melatonin suppresses neuroblastoma growth by mitigating Pak2‑mediated ER stress to induce cytotoxic autophagy.

The present study provided novel insights into melatonin as a promising therapeutic agent for neuroblastoma, warranting further exploration in preclinical models and clinical trials.

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About this publication.

The Di Bella's Method: Use of Melatonin and pseudo-Metronomic Chemotherapy Cyclophosphamide and/or Hydroxyurea (together with others chemical compounds) in Neuroblastoma:

- Neuroblastoma: Complete objective response to biological treatment;

- The Di Bella Method (A Fixed Part - Melatonin tablets. From 30-40mg/day up to 200mg/day and more orally in patients with advanced stage of cancer disease and/or patients without respond to traditional treatments);

- Melatonin use in cancer patients have started in 1974, when melatonin prepared according to Prof. Di Bella’s formulation [...]. For 11 days was administered to the patient, admitted to the general medical ward at the Maggiore-Pizzardi Hospital in Bologna, very slowly (over approx. 8 hours) and intravenously administered 1000 mg of melatonin for 11 days. During the course of each day, the patient was intravenously administered 4 saline drips of 500 ml, each containing ten 25 mg bottles of freeze-dried melatonin, lasting 2 hours, totaling 1000 mg per day. No other drug of any kind was administered in order to ascertain the effect of the MLT without interference [...]. From Melatonin with adenosine solubilized in water and stabilized with glycine for oncological treatment - technical preparation, effectivity and clinical findings;

- About Melatonin - In vitro, review and in vivo publications;

- Publication: Melatonin anticancer effects: Review (from Di Bella's Foundation);

- Publication: Key aspects of melatonin physiology: 30 years of research (from Di Bella's Foundation);

- The Di Bella Method (A Fixed Part - Calcium, 2 grams per day, orally);

- The Di Bella Method (A Fixed Part - Somatostatin, Octreotide, Sandostatin LAR, analogues and/or derivatives);

- Somatostatin in oncology, the overlooked evidences - In vitro, review and in vivo publications;

- Publication, 2018 Jul: Over-Expression of GH/GHR in Breast Cancer and Oncosuppressor Role of Somatostatin as a Physiological Inhibitor (from Di Bella's Foundation);

- Publication, 2018 Sep: The over-expression of GH/GHR in tumour tissues with respect to healthy ones confirms its oncogenic role and the consequent oncosuppressor role of its physiological inhibitor, somatostatin: a review of the literature (from Di Bella's Foundation);

- Publication, 2019 Aug: The Entrapment of Somatostatin in a Lipid Formulation: Retarded Release and Free Radical Reactivity (from Di Bella's Foundation);

- Publication, 2019 Sep: Effects of Somatostatin and Vitamin C on the Fatty Acid Profile of Breast Cancer Cell Membranes (from Di Bella's Foundation);

- Publication, 2019 Sep: Effects of somatostatin, curcumin, and quercetin on the fatty acid profile of breast cancer cell membranes (from Di Bella's Foundation);

- Publication, 2020 Sep: Two neuroendocrine G protein-coupled receptor molecules, somatostatin and melatonin: Physiology of signal transduction and therapeutic perspectives (from Di Bella's Foundation);