Synergistic Effects of New Curcumin Analog (PAC) and Cisplatin on Oral Cancer Therapy

Abstract

Oral cancer has traditionally been treated with surgery, radiotherapy, chemotherapy, or a combination of these therapies. Although cisplatin, a chemotherapy drug, can effectively kill oral cancer cells by forming DNA adducts, its clinical use is limited due to adverse effects and chemo-resistance. Therefore, there is a need to develop new, targeted anticancer drugs to complement chemotherapy, allowing for reduced cisplatin doses and minimizing adverse effects. Recent studies have shown that 3,5-Bis (4-hydroxy-3-methoxybenzylidene)-N-methyl-4-piperidine (PAC), a new curcumin analog, possesses anticancer properties and could be considered a complementary or alternative therapy. In this study, we aimed to assess the potential complementary effects of PAC in combination with cisplatin for treating oral cancer. We conducted experiments using oral cancer cell lines (Ca9-22) treated with different concentrations of cisplatin (ranging from 0.1 μM to 1 μM), either alone or in conjunction with PAC (2.5 and 5 μM). Cell growth was measured using the MTT assay, while cell cytotoxicity was evaluated using an LDH assay. Propidium iodide and annexin V staining were employed to examine the impact on cell apoptosis. Flow cytometry was used to investigate the effects of the PAC/cisplatin combination on cancer cell autophagy, oxidative stress, and DNA damage. Additionally, a Western Blot analysis was performed to assess the influence of this combination on pro-carcinogenic proteins involved in various signaling pathways. The results demonstrated that PAC enhanced the efficacy of cisplatin in a dose-dependent manner, leading to a significant inhibition of oral cancer cell proliferation. Importantly, treatment with PAC (5 μM) alongside different concentrations of cisplatin reduced the IC50 of cisplatin tenfold. Combining these two agents increased apoptosis by further inducing caspase activity. In addition, the concomitant use of PAC and cisplatin enhances oral cancer cell autophagy, ROS, and MitoSOX production. However, combined PAC with cisplatin inhibits the mitochondrial membrane potential (ΔΨm), which is a marker for cell viability. Finally, this combination further enhances the inhibition of oral cancer cell migration via the inhibition of epithelial-to-mesenchymal transition genes, such as E-cadherin. We demonstrated that the combination of PAC and cisplatin markedly enhanced oral cancer cell death by inducing apoptosis, autophagy, and oxidative stress. The data presented indicate that PAC has the potential to serve as a powerful complementary agent to cisplatin in the treatment of gingival squamous cell carcinomas.

Cellular mechanisms mediating the anti-cancer effects of carnosol on gingiva carcinoma

“…As described by Semlali et al 31 , 32 and Contant et al 33 , the cells were washed with phosphate-buffered saline (PBS) and then fixed for 2 min with a solution consisting of 75% methanol and 25% acetic acid. The cells were rewashed before being refixed with the same solution for 5 min.…”

“…The carnosol effect on cell migration was investigated after the application of a scratch in a cell monolayer, as described in our previous works 31 , 36 . The wound diameter was measured over 6 h to evaluate healing properties using the ImageJ 1.47v software, and images were taken using an optical microscope to examine the effects of the drug.…”

An Overview of the Enhanced Effects of Curcumin and Chemotherapeutic Agents in Combined Cancer Treatments

“…The numerous preclinical studies reporting combined treatments with curcumin have shown different benefits since it is able to affect cancer pathways in different ways [ 118 , 119 , 120 ]. These results have increased interest in the use of curcumin in phytotherapy, and so it has been considered in the abovementioned clinical trials.…”

Eugenol as a potential adjuvant therapy for gingival squamous cell carcinoma

“…Cisplatin, also named cis-diaminedichloroplatinum, is considered among the first-line and most effective chemotherapy drug used for the management of oral cancer through generation of DNA lesions and cell apoptosis 11 , 12 . However, being nonselective for cancer cells, many side effects present in the form of bone marrow suppression, hair loss and nausea 13 , 14 . Henceforward, the current focus is leaning towards phytochemicals due to reported effectiveness and reduced adverse effects 13 , 15 .…”

“…However, being nonselective for cancer cells, many side effects present in the form of bone marrow suppression, hair loss and nausea 13 , 14 . Henceforward, the current focus is leaning towards phytochemicals due to reported effectiveness and reduced adverse effects 13 , 15 . In fact, the use of herbal remedies by ancient civilisations led to characterization of active principles that increased the pace of drug discovery.…”