Expression of a novel peptide derived from PCNA damages DNA and reverses cisplatin resistance

Abstract

Background An 8 amino acid peptide sequence derived from proliferating cell nuclear antigen (PCNA) has been shown to effectively kill several breast cancer and neuroblastoma cell lines when added exogenously to cell cultures. Methods In this study, the expression of the 8 amino acid peptide sequence (caPeptide) was placed under control of a tetracycline responsive promoter in MDA-MB-231 cells. Results Endogenous expression of the peptide resulted in an increase in genomic DNA damage. CaPeptide induction combined with treatment of sublethal doses of cisplatin resulted in a marked increase in death of the cisplatin-resistant MDA-MB-231 cell line. CaPeptide was found to interact with POLD3, one of the subunits of DNA polymerase delta necessary for binding to PCNA. Conclusion These results suggest an important line of inquiry into the possible role that caPeptide might play in the reversal of cisplatin resistance in breast and other cancers. This is of particular interest in those cancers where cisplatin is the first line of chemotherapy and where the acquisition of resistance is a common malady.

Validating the disruption of proliferating cell nuclear antigen interactions in the development of targeted cancer therapeutics

“…1A). These patterns observed in HeLa cells are consistent with those observed in the treatment of other types of cancer cell lines, [14][15][16] and therefore is appropriate for use in this study.…”

“…R9-linked caPeptide has demonstrated the ability to target and kill cancer cells, while leaving normal cells virtually unaffected. [14][15][16] Preliminary tests in animal models indicate its potential as a novel therapeutic. 14,15 In this study, the mechanism of action for caPeptide was tested using intact cell ( 3 H-Thymidine uptake) and in vitro (SV40 DNA replication assay) DNA synthesis experiments to measure the inhibitory ability of caPeptide within the replication process.…”

“…When the caPeptide was attached to a 9-arginine (R-conformation) chain (for cellular uptake), R9-caPeptide exhibited cytotoxic activity in numerous cancer cell lines, including: breast cancer (MDA-MB 436, MCF 7, and HCC 1937), pancreatic cancer (PaCa-2), lymphoma (U937), and neuroblastoma (SK-N-DZ, SK-N-BE(2)c, SK-N-AS, SK-N-SH, SK-N-FI) cell lines. [14][15][16] The ultimate goal of this research is to identify and validate specific PCNA-protein interactions effectively blocked by caPeptide during DNA replication. The following studies were conducted in the well-characterized cervical cancer cell line (HeLa).…”

“…breast cancer, neuroblastoma, lymphoma, prostate, pancreatic) exhibit a range of sensitivity to R9-caPeptide treatment. [14][15][16] R9-caPeptide has also demonstrated the ability to effectively inhibit tumor growth in mice bearing xenograft tumors derived from both TNBC (MDA-MB-436) and neuroblastoma (SK-N-BE(2)c) cell lines, further validating the therapeutic potential of the peptide. 14,15 The observed cytotoxicity R9-caPeptide treatment induces in cancer cells is thought to be the direct result of caPeptide interference with caPCNA-protein interactions that are critical to the proper functioning of DNA replication and repair.…”

The Mechanism by Which MYCN Amplification Confers an Enhanced Sensitivity to a PCNA-Derived Cell Permeable Peptide in Neuroblastoma Cells

“…Several protein and peptide-based drugs have successfully reached markets or are currently working their way through different stages of clinical trials ( Stevenson, 2009 ). The ability of R9-caPep to target an essential cellular apparatus and to induce RS in cancer cells without significant toxicity to non-malignant cells ( Gu et al, 2014 , Lingeman et al, 2014 , Smith et al, 2015 ) makes it a promising candidate to combine with Chk1 inhibitors in order to deliver synthetic lethality to cancer cells, especially those driven by the MYC family proteins.…”