BIOLOGICAL SIGNIFICANCE: In this study, proteomic analysis was used to identify abundant proteins from total protein extracts. PEG fractionation was used to reveal lower abundant proteins from both high and low proliferation embryogenic lines of oil palm samples in tissue culture. A total of 40 protein spots were found to be significant in abundance and the mRNA levels of 12 of these were assessed using real time PCR. Three proteins namely, triosephosphate isomerase, l-ascorbate peroxidase and superoxide dismutase were found to be concordant in their mRNA expression and protein abundance. Triosephosphate isomerase is a key enzyme in glycolysis. Both l-ascorbate peroxidase and superoxide dismutase play a role in anti-oxidative scavenging defense systems. These proteins have potential for use as biomarkers to screen for high and low embryogenic oil palm samples.
MATERIALS AND METHODS: Cytotoxicity screening of chalepin against MCF7 cells was conducted using SRB assay. Apoptosis induction was examined by established morphological and biochemical assays including phase contrast and Hoechst/PI staining fluorescence microscope. Similarly, Annexin-V/FITC and TUNEL assays were conducted using flow cytometry whereas caspase-3 activity was evaluated using microplate reader.
KEY FINDINGS: The result indicates remarkable cytotoxic activity against MCF7 cells, whereas it shows moderate cytotoxic activity against MDA-MB231 cells. Interestingly, chalepin did not present any toxicity against MRC5 normal cell line. Morphological examination using both phase contrast and fluorescence microscope displays typical apoptotic features such as membrane blebbing, DNA fragmentation, chromatin condensation and apoptotic bodies' formation following chalepin treatment against MCF7 cells at different concentration for 48 h. Apoptosis induction is significantly associated with externalisation of phosphatidylserine, and DNA fragmentation in MCF7 cells chalepin treated cells when compared with control. The protein expressions of caspase-8, 9 and cleaved PARP1 were upregulated which correlated well with increased caspase-3 activity.
SIGNIFICANCE: From our recent findings, chalepin was able to induced apoptosis in MCF7 cells and therefore, could be evaluated further as a potential source of anticancer agent for cancer treatment such as breast cancer.