The synergistic anti-proliferative effect of the combination of diosmin and BEZ-235 (dactolisib) on the HCT-116 colorectal cancer cell line occurs through inhibition of the PI3K/Akt/mTOR/NF-κB axis

• Published in: Molecular biology reports 2020-03, Vol.47 (3), p.2217-2230
• Main Authors: Helmy, Maged. W., Ghoneim, Asser I., Katary, Mohamed A., Elmahdy, Rana K.
• Format: Article
• Language: English
• Subjects: 1-Phosphatidylinositol 3-kinase; AKT protein; Angiogenesis; Animal Anatomy; Animal Biochemistry; Apoptosis; Autophagy; Biomedical and Life Sciences; Caspase-3; Cell Proliferation - drug effects; Cell Survival - drug effects; Clinical trials; Colorectal cancer; Colorectal carcinoma; Colorectal Neoplasms; Diosmin - pharmacology; Dose-Response Relationship, Drug; Drug Synergism; Gene expression; HCT116 Cells; Histology; Humans; Imidazoles - pharmacology; Life Sciences; Morphology; NF-kappa B - metabolism; NF-κB protein; Original Article; Phagocytosis; Phosphatidylinositol 3-Kinases - metabolism; Phosphorylation; Proto-Oncogene Proteins c-akt - metabolism; Quinolines - pharmacology; Signal transduction; Signal Transduction - drug effects; TOR protein; TOR Serine-Threonine Kinases - metabolism; Toxicity; Tumors; Vascular endothelial growth factor
• ISSN: 0301-4851; 1573-4978
• DOI: 10.1007/s11033-020-05327-4

One of the most lethal malignancies worldwide is colorectal cancer (CRC). Alterations in various signalling pathways, including PI3K-mTOR and NF-κB, have been reported in CRC with subsequent dysregulation of proliferation, apoptosis, angiogenesis and, questionably, autophagy processes. BEZ-235 (dactolisib) is a dual PI3K-mTOR inhibitor with potent anti-tumour activity. However, the observed toxicity of BEZ-235 necessitated the termination of its clinical trials. Hence, we aimed to evaluate the potential long-lasting anti-carcinogenic effects of adding diosmin (DIO, a natural NF-κB inhibitor) to BEZ-235 in HCT-116 CRC cells. The median inhibitory concentrations (IC50s) of BEZ-235 and/or DIO were evaluated in the HCT-116 CRC cell line. Caspase-3 activity was assessed colorimetrically, and p-Akt, NF-κB, CD1, VEGF and LC3B levels were assessed by ELISA. Additionally, LC3-II and P62 gene expression were assessed using qRT-PCR. The observed CIs (combination indices) and DRIs (dose reduction indices) confirmed the synergistic effect of DIO and BEZ-235. Co-administration of both drugs either in combination-1 (1 μM for BEZ-235, 250 μM for DIO) or in combination-2 (0.51 μM for BEZ-235 + 101.99 μM for DIO) inhibited the PI3K/Akt/mTOR/NF-κB axis, leading to the induction of apoptosis (via active caspase-3), and the inhibition of proliferation marker (CD1), angiogenesis marker (VEGF), autophagy protein (LC3B) and altered effects on LC3-II and P62 gene expression. Our results reveal the synergistic chemotherapeutic effects of DIO combined with BEZ-235 in the HCT-116 CRC cell line and encourage future preclinical and clinical studies of this combination with reduced BEZ-235 concentrations to avoid its reported toxicity. Graphic abstract