Acetylenic Synthetic Betulin Derivatives Inhibit Akt and Erk Kinases Activity, Trigger Apoptosis and Suppress Proliferation of Neuroblastoma and Rhabdomyosarcoma Cell Lines

Abstract

Neuroblastoma (NB) and rhabdomyosarcoma (RMS), the most common pediatric extracranial solid tumors, still represent an important clinical challenge since no effective treatment is available for metastatic and recurrent disease. Hence, there is an urgent need for the development of new chemotherapeutics to improve the outcome of patients. Betulin (Bet), a triterpenoid from the bark of birches, demonstrated interesting anti-cancer potential. The modification of natural phytochemicals with evidenced anti-tumor activity, including Bet, is one of the methods of receiving new compounds for potential implementation in oncological treatment. Here, we showed that two acetylenic synthetic Bet derivatives (ASBDs), EB5 and EB25/1, reduced the viability and proliferation of SK-N-AS and TE671 cells, as measured by MTT and BrdU tests, respectively. Moreover, ASBDs were also more cytotoxic than temozolomide (TMZ) and cisplatin (cis-diaminedichloroplatinum [II], CDDP) in vitro, and the combination of EB5 with CDDP enhanced anti-cancer effects. We also showed the slowdown of cell cycle progression at S/G2 phases mediated by EB5 using FACS flow cytometry. The decreased viability and proliferation of pediatric cancers cells after treatment with ASBDs was linked to the reduced activity of kinases Akt, Erk1/2 and p38 and the induction of apoptosis, as investigated using Western blotting and FACS. In addition, in silico analyses of the ADMET profile found EB5 to be a promising anti-cancer drug candidate that would benefit from further investigation.

The Influence of Betulin and Its Derivatives EB5 and ECH147 on the Antioxidant Status of Human Renal Proximal Tubule Epithelial Cells

“…Its availability and the ease of obtaining it from birch bark encourage the search for new therapeutic solutions [ 1 ]. Betulin modifications, such as the 28-propyne derivative EB5 and its 29-diethyl phosphonate analog ECH147, showed promising results in anti-tumor activity studies [ 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. Despite the promising results of research on the biological activity of betulin and its derivatives, these compounds, so far, have not been used in pharmacotherapy due to their low bioavailability resulting from limited solubility in the water environment.…”

“…Introducing various new structural elements into the betulin molecule is related to the search for compounds that are characterized by better pharmacokinetic parameters while maintaining biological activity. Previously conducted studies of the 28-propynoyl derivative of betulin EB5 and its 29-diethyl phosphonate analog ECH147 against various tumor cell lines have shown promising results ( Table S1; Supplementary Materials ) [ 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. It should be noted that the anticancer activity of betulin and its derivatives may result from their effect on mitochondria due to their hydrophobic nature and then the induction of oxidative stress [ 17 ].…”

Targeting regulated cell death with plant natural compounds for cancer therapy: A revisited review of apoptosis, autophagy‐dependent cell death, and necroptosis

“…Betulin, a triterpenoid extracted from Isatidis Radix , induces autophagy in colorectal cancer cells by inhibiting the phosphatidylinositol 3 kinase/protein kinase B (PI3K/AKT)/mTOR signaling pathway (Han, Mun, Jeon, Kee, & Hong, 2019). Moreover, two derivatives of Betulin, 28‐O‐propynoylbetulin and 28‐O‐propargyloxycarbonylbetulin, have been reported to exhibit better antitumor activities (Król et al, 2021). Ursolic acid, a triterpenoid isolated from Hedyotis Diffusae Herba , can inhibit the growth and metastasis of cancer cells by inducing autophagy through increasing ROS (Lee et al, 2020).…”