Development of a peptide-based bifunctional chelator conjugated to a cytotoxic drug for the treatment of melanotic melanoma

Raghuvir H Gaonkar; Rinku Baishya; Brahamacharry Paul; Saikat Dewanjee; Shantanu Ganguly; Mita C Debnath; Soumya Ganguly

doi:10.1039/c7md00638a

Development of a peptide-based bifunctional chelator conjugated to a cytotoxic drug for the treatment of melanotic melanoma

Medchemcomm. 2018 Mar 6;9(5):812-826. doi: 10.1039/c7md00638a. eCollection 2018 May 1.

Authors

Raghuvir H Gaonkar¹, Rinku Baishya², Brahamacharry Paul¹, Saikat Dewanjee³, Shantanu Ganguly⁴, Mita C Debnath¹, Soumya Ganguly¹

Affiliations

¹ Infectious Diseases and Immunology Division , CSIR-Indian Institute of Chemical Biology , Kolkata , India . Email: mitacd@iicb.res.in.
² Natural Product Chemistry Group , Chemical Science and Technology Division , North East Institute of Science and Technology , Assam , India.
³ Advanced Pharmacognosy Research Laboratory , Department of Pharmaceutical Technology , Jadavpur University , Kolkata , India.
⁴ Regional Radiation Medicine Center , Thakurpukur Cancer Center and Welfare Home Campus , Kolkata , India.

Abstract

The cytotoxic drug gemcitabine (GEM) has been conjugated to receptor-binding peptides to target melanoma tumors. A hexapeptide having a Lys-Gly-His-Lys sequence (pep-1), an octapeptide with an Arg-Gly-Asp-Lys-Gly-His-Lys sequence (pep-2), a GEM-conjugated Lys-Gly-His-Lys peptide (GEM-pep-3) and a GEM-conjugated Asp-Gly-Arg peptide (GEM-pep-4) were synthesized and characterized. In vitro uptake of fluorescently labeled GEM-pep-3 and GEM-pep-4 on B16F10 cells was investigated. Fluorescence microscopy studies demonstrated significant uptake of GEM-pep-3 in the B16F10 mouse melanoma cell line. The peptides and GEM-coupled peptides were radiolabeled with [^99mTc(CO)₃(H₂O)₃]⁺ and examined for in vitro cell binding in the B16F10 melanoma cell line and in vivo biodistribution and scintigraphic studies in a B16F10 melanoma tumor-bearing mice model. In vitro cellular uptake studies and biological evaluation confirmed significant deposition of GEM-pep-3 at the melanoma tumor site. The MTT assay depicted higher cytotoxic behaviour of GEM-pep-3 than free GEM. A considerable amount of cell apoptosis was also observed in B16F10 cells. Finally, the in vivo therapeutic efficacy study revealed a significant decrease in tumor growth in the GEM-pep-3-treated animal model. These studies reveal enough potentiality of GEM-pep-3 to treat melanoma and underline the need for further evaluation.