Silibinin, A Natural Blend In Polytherapy Formulation For Targeting Cd44v6 Expressing Colon Cancer Stem Cells

Abstract

Colon cancer stem cells have been attributed to poor prognosis, therapeutic resistance and aggressive nature of the malignancy. Recent reports associated CD44v6 expression with relapse, metastasis and reduced 5-year survival of colon cancer patients, thereby making it a potential therapeutic target. Thus, in this study, comprehensive prediction and screening of CD44v6 against 1674 lead compounds was conducted. Silibinin was identified as a potential compound targeting CD44v6. Inorder to substantiate these findings, the cytotoxic effect of 5FU, Silibinin and 5FU+ Silibinin was assessed on human colon carcinoma cell line HCT116 derived CD44+ subpopulation. 5FU+ Silibinin inhibited cell proliferation of CD44+ subpopulation at lower concentration than Silibinin standalone. Further, corresponding to CD44v6 knockdown cells, 5FU+ Silibinin treatment significantly decreased CD44v6, Nanog, CTNNB1 and CDKN2A expression whereas increased E-cadherin expression in HCT116 derived CD44+ cells. Moreover, synergistic effect of these drugs suppressed sphere formation, inhibited cell migration, triggered PARP cleavage and perturbation in mitochondrial membrane potential, thereby activating intrinsic apoptotic pathways and induced autophagic cell death. Importantly, 5FU+ Silibinin could inhibit PI3K/MAPK dual activation and arrest the cell cycle at G0/G1 phase. Thus, our study suggests that inhibition of CD44v6 attenuates stemness of colon cancer stem cells and holds a prospect of potent therapeutic target.

Molecular insight into isoform specific inhibition of PI3K-α and PKC-η with dietary agents through an ensemble pharmacophore and docking studies

“…In the case of silibinin- PKC-η complex, it showed six bonds: the 3, 7 hydroxyl, and 1O groups of the benzopyran bonded with Asp 497 , Val 436 , Leu 486 , and the methoxyphenyl bonded with Asp 440 , whereas in the case of Ras-silibinin complex, it has been shown to have bonds of 7-OH and 1O atoms of the benzopyran with Lys 317 , Phe 228 , and Gly 213 , and the 1, 4 dibenzodioxins and an OH groups with Thr 235 . In addition, previous studies have reported a wide range of silibinin pharmacological activity, such as the STAT3 inhibitor 66 , anti-inflammatory, anti-PI3K-α and MAPK, cell cycle arrest at G 0 /G 1 phase and p38 MAPK inhibitor 67 , 68 , respectively. The silibinin have shown a broad-spectrum pharmacological effect on multiple drug targets and, therefore, can be utilized as a potential lead scaffold for further design of novel anticancer drugs with combined drug discovery and clinical study approach.…”

Deregulation of miR-34a, miR-221 and miR-222 after HT29 cells treatment with Silibinin encapsulated in polymersomes as an anti-cancer stem cell agent

“…apoptosis Induction by Silibinin ( 144 µg/ml) for 48-72h on SW480 and SW620 colorectal cancer cell lines was reported (21%-31% and 23%-40% late apoptosis, respectively) [36]. The total percentage of apoptosis in colorectal cancer cell line HCT116-CD44+ after induction of 120 µg/ml of Silibinin was 11.6% and 29.5% at 24 and 48h, respectively [37]. Our analysis revealed that late and total apoptosis percentage increased signi cantly to 25.5% and 32.36% in SPNs treated cells (28µg/ml) only after 24h.…”

“…Also, the cell growth inhibition doses of Silibinin on SW480 and SW620 colorectal cancer cell line was evaluated by Henriette Kauntz and observed that it was 40-100 µg/ml within 8 days [36]. Shanaya Patel et.al also showed that Silibinin inhibited cell proliferation of HCT116-CD44+ subpopulation of colon cancer stem cells at 120 µg/ml [37]. In our previous study, we synthetized a polymersome nanocarrier that due to suitable properties(appropriate size, narrow size distribution, higher Encapsulation E ciency (EE) and Drug Loading (DL)) [29] we again used in this study.…”

Functional analysis of CD44 variants and xCT in canine tumours

“…Alternative mRNA splicing of CD44 is mediated by epithelial splicing regulatory protein 1 (ESRP1), (Brown et al., 2011; Jeong et al., 2017; Preca et al., 2015; Yae et al., 2012) and several reports have suggested that the upregulation of ESRP1 is associated with poor prognosis of tumours (Jeong et al., 2017; Yae et al., 2012). A variety of CD44v isoforms generated by ESRP1, such as CD44v6 and CD44v8‐10, have been shown to be involved in multiple cellular functions, including proliferation, adhesion and metastasis (Hirata et al., 2013; Horibe et al., 2018; Ishimoto et al., 2011; Li et al., 2014; Nagano et al., 2013; Ogihara et al., 2019; Patel et al., 2018; Wada et al., 2018; Wu et al., 2015; Yoshikawa et al., 2013). In canine, it has been reported that CD44v3, v6 and v7 mRNAs are expressed in B‐cell lymphoma, and the expression of these mRNAs is associated with chemo‐resistance and a poor prognosis (Motegi et al., 2018).…”