Abstract

Pancreatic cancer is the fifth leading cause of cancer death and has the lowest survival rate of any solid cancer in the industrial countries. The poor prognosis of pancreatic cancer results from its tendency for late presentation, aggressive invasion, early metastasis, and resistance to chemotherapy. Gemcitabine still remains the best chemotherapeutic agent available for the treatment of advanced pancreatic cancer. However, gemcitabine treatment results in only a marginal survival advantage. Thus there is a strong need for the continual development of novel therapeutic agents to improve pancreatic cancer therapy. The compound C-1748 is the most active derivative of 1-nitroacridine antitumor agents developed in our laboratory. Strong cytotoxic activity against colon cancer cell lines (HCT8 and HT29) and high antitumour activity against xenografts in nude mice of prostate (LnCaP) and colon carcinoma (HCT8), along with low mutagenic potential and slight myelosuppressive properties allowed the selection of C-1748 for phase I clinical trials.The aim of the current study was to investigate and characterize the cellular response of human pancreatic cancer cell line MiaPaca-2 to C-1748 treatment. This cell line was selected due to its high sensitivity to C-1748. Cell cycle analysis revealed that between 24 h and 48 h of C-1748 treatment, MiaPaca-2 cells underwent transient accumulation in the G2/M phase which was followed by prolonged arrest in the G1 phase. Starting from 96 h of drug exposure, decrease in G1 phase population was accompanied by progressive increase in sub-G1 fraction, suggesting that initial G1 arrest led to cell death through apoptosis. Morphological changes of MiaPaca-2 cells in response to C-1748 treatment were observed using fluorescent microscopy. DAPI staining revealed that cells exposed to C-1748 exhibited features characteristic for apoptosis: condensed chromatin and apoptosis-body like structures. The drug induced apoptosis in time- and dose-dependent manner was also confirmed by flow cytometry analysis. Caspase-3 activation, phosphatydylserine externalization and mitochondrial dysfunction typical for apoptosis were detectable already after 24 h of treatment. To sum up, major cellular response triggered by C-1748 in MiaPaca-2 cells was the effective induction of apoptosis. These results highlight the therapeutic potential of C-1748 in pancreatic cancer and support rationale for its further investigation towards this type of malignancy.

Authors (4)