A novel microtubule de-stabilizing complementarity-determining region C36L1 peptide displays antitumor activity against melanoma in vitro and in vivo

Abstract

Short peptide sequences from complementarity-determining regions (CDRs) of different immunoglobulins may exert anti-infective, immunomodulatory and antitumor activities regardless of the specificity of the original monoclonal antibody (mAb). In this sense, they resemble early molecules of innate immunity. C36L1 was identified as a bioactive light-chain CDR1 peptide by screening 19 conserved CDR sequences targeting murine B16F10-Nex2 melanoma. The 17-amino acid peptide is readily taken up by melanoma cells and acts on microtubules causing depolymerization, stress of the endoplasmic reticulum and intrinsic apoptosis. At low concentrations, C36L1 inhibited migration, invasion and proliferation of B16F10-Nex2 cells with cell cycle arrest at G2/M phase, by regulating the PI3K/Akt signaling axis involving Rho-GTPase and PTEN mediation. Peritumor injection of the peptide delayed growth of subcutaneously grafted melanoma cells. Intraperitoneal administration of C36L1 induced a significant immune-response dependent anti-tumor protection in a syngeneic metastatic melanoma model. Dendritic cells stimulated ex-vivo by the peptide and transferred to animals challenged with tumor cells were equally effective. The C36 VL CDR1 peptide is a promising microtubule-interacting drug that induces tumor cell death by apoptosis and inhibits metastases of highly aggressive melanoma cells.

Interfering with MIF-CD74 signalling on macrophages and dendritic cells with a peptide-based approach restores the immune response against metastatic melanoma

“…We have previously shown that intraperitoneal injections of the anti-tumour CDR peptide C36L1 significantly decrease pulmonary melanoma metastasis in a syngeneic model (24,25). In addition, bone marrow derived myeloid pro-inflammatory dendritic cells (DCs) displayed equivalent anti-tumour effect when tumor antigen-primed DCs were pre-treated with C36L1 ex vivo and adoptively transferred to mice bearing lung melanoma metastasis (24). These findings suggest that the anti-tumour effects induced by C36L1 in vivo may result from the peptide ability to stimulate the host immune response.…”

“…Synthetic peptides based on Immunoglobulin-CDR sequences have shown promising antitumour properties, and some of these peptides display immune stimulatory functions (22,(24)(25)(26). The C36 V L CDR1 peptide (C36L1) was initially identified as an anti-melanoma agent (25) that inhibits melanoma cells survival and proliferation (24).…”

“…Peptide C36L1 binding to CD74 was determined by chemiluminescent (CL) dot-blotting carried out as previously described (24). Briefly, 25 nmoles of C36L1 and the irrelevant CDR peptide control (iCDR) and vehicle (0.025% DMSO in dH 2 O) were carefully dotted in 10 μL of dH 2 O on nitrocellulose membranes, and blocked with 1% TBS-Tween (TBS-T) in 5% BSA for 1h at 4 °C.…”

“…Bioactive peptides based on immunoglobulin complementary determining regions (CDRs) are promising candidates for adjuvant cancer therapy and can stimulate the innate immune system (22)(23)(24). We have previously shown that different CDR peptides display anti-tumour activities against melanoma, and are able to regulate receptors and transcription factors on both tumour cells and immune cells (24)(25)(26)(27)(28). Recently, we identified the C36 V L CDR-1 peptide (C36L1) as an anti-tumour CDR-based peptide that inhibits metastatic melanoma cells proliferation and growth in vitro and in vivo (24,25).…”

“…We have previously shown that different CDR peptides display anti-tumour activities against melanoma, and are able to regulate receptors and transcription factors on both tumour cells and immune cells (24)(25)(26)(27)(28). Recently, we identified the C36 V L CDR-1 peptide (C36L1) as an anti-tumour CDR-based peptide that inhibits metastatic melanoma cells proliferation and growth in vitro and in vivo (24,25). However, the mechanism by which C36L1 inhibits metastatic melanoma progression in a syngeneic model remains unknown.…”