Melatonin increases the anticancer potential of doxorubicin in Caco-2 colorectal cancer cells.

Mahdieh Farhoudi Sefidan Jadid,Elnaz Aghaei,Reza Chavoshi,Afshin Khorrami,Sina Taefehshokr,Pouya Goleij,Alireza Isazadeh,Saba Hajazimian,Dariush Shanehbandi,Samane Abbasi,Elham Taheri,Nasrin Seyyedsani

doi:10.1002/tox.23105

Abstract

Colorectal cancer (CC) is an important human malignancy with high cancer related death worldwide. The chemotherapy using doxorubicin hydrochloride is one of the most common cancer therapeutic methods. However, drug resistance lowers the treatment efficacy in CC patients. The combination therapies seem to be more promising by taking the advantage of synergistic effects. The present study aimed to evaluate a new strategy to enhance the anticancer activity of doxorubicin in Caco-2 CC cell line by co-administration of melatonin. The effects of doxorubicin, melatonin, and their combinations (Dox-Mel) were investigated on the proliferation and viability, morphological alterations, and tumor spheroid formation. Flow cytometry was employed to compare the apoptotic situation of the cells in study groups. Changes in metastatic potential of the cells were assessed by wound healing assay and trans-well migration assays. Moreover, expression of BAX, SMAC, BCL-2, SURVIVIN, MMP-2, and MMP-9 genes were evaluated by quantitative real time PCR and western blotting. Our study showed that doxorubicin, melatonin, and Dox-Mel significantly decreased the proliferation and viability, tumor spheroid formation, invasion, and migration. Furthermore, the changes were in a concentration and time dependent manner. There was an increase in apoptosis rate in the treatment groups. Expression of genes involved in apoptosis and cell motility were altered significantly. It was observed that anticancer activity of Dox-Mel combination was significantly more than doxorubicin and melatonin treatments alone. We showed an enhanced apoptotic and anticancer activity of doxorubicin and melatonin combination chemotherapy on CC cell line than doxorubicin or melatonin treatments alone. This combination could promote the treatment efficiency and alleviate the un-intended side effects by lowering the dose of doxorubicin prescription.

Highlights

Colorectal cancer (CC) is a highly prevalent malignancy and causative of cancer related death in the world
The viability of the cancer cells was significantly decreased in the high concentrations of doxorubicin and melatonin
The cancer cells treated with doxorubicin, melatonin, and Dox-Mel showed several morphological alterations including shrinkage, decreased cell size, fragmented nuclei, and membrane damages, which can result in programmed cell death

Summary

Introduction

Colorectal cancer (CC) is a highly prevalent malignancy and causative of cancer related death in the world. Surgery and chemotherapy are the most common methods for treatment of CC. Due to development of drug-resistant CC cells the efficacy of chemotherapy is limited (Wang et al, 2017). Doxorubicin is an anthracycline antibiotic, commonly used as a chemotherapeutic agent in treatment of patients with CC. This chemotherapy agent inhibits cancer cells through induction of apoptosis and inhibition of cell division. The upregulation of efflux transporters decreases intracellular levels of doxorubicin through drug excretion. This leads to reduction of therapeutic efficacy and apoptosis rate in drug-resistant cancer cells. Anticancer activity of doxorubicin decreases in cancer cells with inhibited apoptosis. Various molecular processes are involved in dysregulation of apoptotic pathways including: activation of anti-apoptotic factors (Bcl-2, Bfl1/A1, etc.), inactivation of pro-apoptotic factors (Smac, Bax, etc.), and reinforcement of survival signals (Survivin, NF-κB, etc.)

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