Flavonoids Induce Migration Arrest and Apoptosis in Detroit 562 Oropharynx Squamous Cell Carcinoma Cells

Kaempferol and Fisetin-Related Signaling Pathways Induce Apoptosis in Head and Neck Cancer Cells

Despite the relative effectiveness of standard cancer treatment strategies, head and neck cancer (HNC) is still considered one of the leading causes of mortality and morbidity. While selected bioactive compounds of plant origin reveal a pro-apoptotic effect, kaempferol and fisetin flavonols have been reported as potential anti-cancer agents against malignant neoplasms. To date, their exact role in signaling pathways of head and neck cancer cells is largely unknown. Based on the various methods of cytotoxicity testing, we elucidated that kaempferol and fisetin inhibit proliferation, reduce the capacity of cell migration, and induce apoptosis in SCC-9, SCC-25, and A-253 HNC cells in a dose-dependent manner in vitro (p < 0.05, fisetin IC₅₀ values of 38.85 µM, 62.34 µM, and 49.21 µM, and 45.03 µM, 49.90 µM, and 47.49 µM for kaempferol-SCC-9, SCC-25, and A-253, respectively). The obtained results showed that exposure to kaempferol and fisetin reduces Bcl-2 protein expression, simultaneously leading to the arrest in the G2/M and S phases of the cell cycle. Kaempferol and fisetin inhibit cell proliferation by interfering with the cell cycle, which is strongly associated with the induction of G2/M arrest, and induce apoptosis by activating caspase-3 and releasing cytochrome c in human HNC cells. In addition, investigating flavonols, by inhibiting anti-apoptotic proteins from the Bcl-2 family and damaging the mitochondrial transmembrane potential, increased the level of cytochrome c. While flavonols selectively induce apoptosis of head and neck cancer cells, they may support oncological therapy as promising agents. The discovery of new derivatives may be a breakthrough in the search for effective chemotherapeutic agents with less toxicity and thus fewer side effects.

Fisetin, a Potent Anticancer Flavonol Exhibiting Cytotoxic Activity against Neoplastic Malignant Cells and Cancerous Conditions: A Scoping, Comprehensive Review

Diet plays a crucial role in homeostasis maintenance. Plants and spices containing flavonoids have been widely used in traditional medicine for thousands of years. Flavonols present in our diet may prevent cancer initiation, promotion and progression by modulating important enzymes and receptors in signal transduction pathways related to proliferation, differentiation, apoptosis, inflammation, angiogenesis, metastasis and reversal of multidrug resistance. The anticancer activity of fisetin has been widely documented in numerous in vitro and in vivo studies. This review summarizes the worldwide, evidence-based research on the activity of fisetin toward various types of cancerous conditions, while describing the chemopreventive and therapeutic effects, molecular targets and mechanisms that contribute to the observed anticancer activity of fisetin. In addition, this review synthesized the results from preclinical studies on the use of fisetin as an anticancer agent. Based on the available literature, it might be suggested that fisetin has a bioactive potential to become a complementary drug in the prevention and treatment of cancerous conditions. However, more in-depth research is required to validate current data, so that this compound or its derivatives can enter the clinical trial phase.