Gamabufotalin induces a negative feedback loop connecting ATP1A3 expression and the AQP4 pathway to promote temozolomide sensitivity in glioblastoma cells by targeting the amino acid Thr794

Abstract

Objectives: Temozolomide (TMZ) is one of the most commonly used clinical drugs for glioblastoma (GBM) treatment, but its drug sensitivity needs to be improved.Gamabufotalin (CS-6), the primary component of the traditional Chinese medicine "ChanSu," was shown to have strong anti-cancer activity. However, more efforts should be directed towards reducing its toxicity or effective treatment doses.Methods: Target fishing experiment, Western blotting, PCR, confocal immunofluorescence and molecular cloning techniques were performed to search for possible downstream signalling pathways. In addition, GBM xenografts were used to further determine the potential molecular mechanisms of the synergistic effects of CS-6 and TMZ in vivo. Results: Mechanistic research revealed a negative feedback loop between ATP1A3and AQP4 through which CS-6 inhibited GBM growth and mediated the synergistic treatment effect of CS-6 and TMZ. In addition, by mutating potential amino acid residues of ATP1A3, which were predicted by modelling and docking to interact with CS-6, we demonstrated that abrogating hydrogen bonding of the amino acid Thr794 interferes with the activation of ATP1A3 by CS-6 and that the Thr794Ala mutation directly affects the synergistic treatment efficacy of CS-6 and TMZ. Conclusions:As the main potential target of CS-6, ATP1A3 activation critically depends on the hydrogen bonding of Thr794 with CS-6. The combination of CS-6 and TMZ could significantly reduce the therapeutic doses and promote the anti-cancer efficacy of CS-6/TMZ monotherapy.

A Bioinformatics Analysis of the Potential Roles of Aquaporin 4 in Human Brain Tumors: An Immune-Related Process

“…2015; Zou et al, 2020;Lan et al, 2020). Nevertheless, precise mechanisms have yet to be fully elucidated.…”

“…Recent evidence suggests that AQP4 expression may be linked to several diseases such as cancer ( Papadopoulos and Saadoun, 2015 ; Zou et al, 2020 ; Lan et al, 2020 ). Nevertheless, precise mechanisms have yet to be fully elucidated.…”

“…Our previous research indicated that AQP4 could be was found in high concentrations in brain cancer tissues and that AQP4 could also impact the overall survival of cancer patients ( Lan et al, 2020 ). However, the roles of AQP4 in immunity, as well as in various other brain cancers have not been identified systematically.…”

“…Recent literature highlights the central role of AQP4 in cancer initiation and progression ( Papadopoulos and Saadoun, 2015 ; Lan et al, 2020 ; Zou et al, 2020 ). Understanding its roles in tumorigenesis and tumor development is indispensable knowledge that contributes toward the development of molecular-targeted therapies.…”

Potassium channel-related genes are a novel prognostic signature for the tumor microenvironment of renal clear cell carcinoma

“…It has been reported that bufalin inhibits the growth of hepatocellular carcinoma (HCC) cells, which is correlated with the expression level of ATP1A3 in HCC cells ( 39 ). Another study reported that activation of ATP1A3 could sensitize glioblastoma cells to temozolomide ( 41 ). However, the role of PCRGs in the development of ccRCC has not been reported, and further research is needed.…”