Mechanisms underlying the cytotoxic effect of propolis on human laryngeal epidermoid carcinoma cells

Abstract

Propolis has been used as a traditional remedy for centuries because of its beneficial effects, including anticancer properties. The aim of this study was to compare the cytotoxic mechanism of Cuban red propolis (CP) and Brazilian green propolis (BP) on human laryngeal carcinoma (HEp-2) cells. Cell viability, leakage of lactate dehydrogenase, fluorescence staining, mitochondrial membrane potential (ΔΨm) and the expression of pro/anti-apoptotic genes were assessed. Cell viability and cytotoxic assays suggested a dose-dependent effect of CP and BP extracts with a possible association of intracellular reactive oxygen species production and decreased ΔΨm. Both samples induced apoptosis via activation of TP53, CASP3, BAX, P21 signalling, and downregulation of BCL2 and BCL-XL. CP exerted a higher cytotoxic effect than BP extract. Our findings suggest further investigation of the main components of each propolis sample, what may lead to the development of strategies for the treatment of laryngeal cancer.

Digital Analysis of BCL2 Expression in Laryngeal Squamous Cell Carcinoma

“…BCL2 overexpression is a negative regulator for successful radiotherapy implementation by reducing the apoptotic process. For this reason, development of synthetic agents or application of natural anti-BCL2 agents, such as propolis, which demonstrated strong cytotoxic anticancer activity (17), is a very promising chemotherapeutic strategy for stabilizing and enhancing apoptosis in patients with LSCC.…”

Anticancer Activity of Propolis and Its Compounds

“…Extracts induce apoptosis by activating TP53, CASP3, BAX, p21 signaling and downregulating BCL2, BCL-XL, and PUMA. But in a similar study, researchers found that Brazilian propolis did not affect BCL-2, BCL-XL, NOXA, and PUMA expression [ 108 , 109 ].…”

“…Propolis and its components modulate the ability of cancer cells to migrate and invade through MAPK and PI3K/AKT signaling pathways [ 28 , 30 , 42 , 43 , 108 ]. The c-prenylflavonones, including propolin C, are specific active compounds of propolis from East Pacific regions, such as Taiwan and Okinawa [ 30 ].…”

Tumor-suppressing potential of stingless bee propolis in in vitro and in vivo models of differentiated-type gastric adenocarcinoma

“…Concordantly, propolis administration has similarly provoked the differential induction of apoptosis-associated markers in previous studies of various human cancer cell lines. While it has initiated DNA fragmentation via activation of BAX and inhibition of BCL2 and BCL-XL (encoded by the BCL2L1 gene) in laryngeal carcinoma Hep-2 cells and colon carcinoma HL-60 cells 33,61 , a decrease in BCL2 without alteration in BAX was reported in another study using U937 leukemic cells 24 . At present, we could hardly offer any substantial rationalization to what seems to be a specific regulatory role of our propolis sample on the in vivo gene expressions of Bad and Bcl2l1 in expending its apoptotic effect.…”