Abstract
Pancreatic cancer is deemed one of the most aggressive types of cancer, with a high mortality rate and poor prognosis. It is ranked the 12th most prevalent cancer globally, with 510,992 new cases and 467,409 deaths reported in 2022. In South Africa, it is ranked the 9th most common cancer with a mortality rate of approximately 84%. Pancreatic cancer is often diagnosed in advanced stages when the disease is too aggressive to manage, rendering the available treatments ineffective. Cannabis sativa (C. sativa) is a medicinal plant that has been used for centuries based on its health benefits; more recently, it has been explored for its anti-cancer properties. However, knowledge on the impact of C. sativa on pancreatic cancer is still limited. This study was aimed at exploring the apoptosis-inducing potential of C. sativa and cannabidiol (CBD) in pancreatic cancer cells. Crude C. sativa extracts were obtained by dissolving dried C. sativa leaves in absolute ethanol, CBD was isolated from the crude extract using column chromatography. The cytotoxic effects of the crude extract and CBD on pancreatic cancer cells (Mia-PaCa2) and normal lung cells (MRC-5) were determined using AlamarBlue reagent. Apoptosis was investigated by analysing morphological changes using light microscopy. This was followed by evaluation of phosphatidylserine externalisation and nuclear condensation, hallmarks of apoptosis, using Annexin V staining and Hoechst staining, respectively. Furthermore, levels of ATP and activation of caspase-3 and -7, key executioners of apoptosis were measured. DNA fragmentation was analysed using agarose gel electrophoresis. Lastly, gene expression of apoptosis related genes was assessed using quantitative polymerase chain reaction (qPCR). The results show that both the crude and CBD induced substantial cytotoxic effects on Mia-PaCa2 cells but not MRC-5. C. sativa and CBD caused significant morphological changes on Mia-PaCa2 cells including cell detachment and rounding, phosphatidylserine externalisation, and nuclear condensation as seen through light microscopy, Annexin V staining, and Hoechst staining. Furthermore, the crude and CBD extracts reduced ATP levels and activated caspase-3 and -7 with the effects more pronounced with the crude extract. DNA fragmentation was also more distinct in cells treated with the crude extract, validating the notion that both crude C. sativa and CBD induced apoptosis in Mia-PaCa2. This was further supported by the upregulation of BAX, BAK-1, and p53 and the downregulation of BCL-2, indicating the activation of the intrinsic apoptotic pathway. In conclusion, both crude and CBD have apoptosis-inducing potential in pancreatic cancer cells.