Hesperetin regulates PI3K/Akt and mTOR pathways to exhibit its antiproliferative effect against colon cancer cells.

Hesperetin, a citrus flavonoid, has been a widely studied anticancer agent against many types of cancers, but the exact mechanism of efficacy is still unrevealed. Therefore, this study has attempted to delineate the mechanical aspect of hesperetin's anticancer efficacy against colon cancer using immunoblotting, scanning, and transmission electron microscopic studies. The treatment with hesperetin (25 and 50 µM) has significantly (p < 0.0001) curbed down the proliferation and cell viability of HCT-15 cells in a concentration as well as time dependent manner. Hesperetin was able to achieve this through the induction of caspase-dependent apoptosis. Moreover, hesperetin effectively inhibited phosphorylation of Akt with a parallel increase in PTEN expression thereby inhibiting the PI3K signaling axis, which contributes to the suppression of proliferation. In addition, hesperetin enhanced autophagy through dephosphorylating mTOR, one of the downstream targets of Akt with simultaneous acceleration in Beclin-1 and LC3-II expression levels. Interestingly, hesperetin enhanced the effects of Akt inhibitor LY294002 and mTOR inhibitor rapamycin. This study documented the potential of hesperetin to induce apoptosis through simultaneous acceleration over the autophagic process in colon cancer cells. Thus, hesperetin played a beneficial therapeutic role in preventing colon carcinoma growth by regulating the Akt and mTOR signaling axis.

Berberine inhibits Smad and non-Smad signaling cascades and enhances autophagy against pulmonary fibrosis.

UNLABELLED: Idiopathic pulmonary fibrosis (IPF) is a fibroproliferative lung disorder of unknown aetiology. Transforming growth factor-ß1 (TGF-ß1)-mediated Smad and non-Smad signaling cascades are considered as central players in accelerating pulmonary fibrosis. We earlier reported berberine's amelioration against TGF-ß1-mediated pro-fibrotic effects in bleomycin-induced pulmonary fibrosis. The present study aimed to determine the regulatory role of berberine on abrogated Smad 2/3 and FAK-dependent PI3K/Akt-mTOR signaling cascades in bleomycin-induced pulmonary fibrosis. Male Wistar rats were subjected to single intratracheal instillation of bleomycin (2.5 U/kg) on day 0, and berberine treatments were provided in either preventive or therapeutic modes, respectively. Berberine mitigated the elevated expression of fibrotic markers, α-smooth muscle actin (α-SMA), fibronectin, collagens I and III and reversed bleomycin-induced ultrastructural alterations in the lungs. Berberine inhibited the bleomycin-induced raise in p-Smad 2/3 and enhanced Smad 7 expression. Berberine blocked the activation of FAK and PI3K/Akt against bleomycin-induced dysregulation, with subsequent raise in PTEN expression. In addition, by inhibiting p-mTOR, berberine stimulated autophagy as evidenced by increase in Beclin-1, LC3-II levels with enhanced autophagosome formation. Cumulatively, through targeted inhibition of dysregulated Smad and FAK-dependent PI3K/Akt-mTOR signaling axis, berberine attenuated the fibrotic insults of bleomycin. KEY MESSAGE: Berberine inhibits Smad 2/3 activation and enhances Smad 7 in bleomycin-induced rat lungs. Bleomycin-induced activation of FAK is inhibited by berberine. Berberine inhibits bleomycin-induced activation of PI3K/Akt cascade. Berberine inhibits mTOR activation to enhance autophagy and suppresses fibrotic markers.

Hesperidin induces apoptosis and triggers autophagic markers through inhibition of Aurora-A mediated phosphoinositide-3-kinase/Akt/mammalian target of rapamycin and glycogen synthase kinase-3 beta signalling cascades in experimental colon carcinogenesis.

Abnormalities in the homeostasis mechanisms involved in cell survival and apoptosis are contributing factors for colon carcinogenesis. Interventions of these mechanisms by pharmacologically safer agents gain predominance in colon cancer prevention. We previously reported the chemopreventive efficacy of hesperidin against colon carcinogenesis. In the present study, we aimed at investigating the potential of hesperidin over the abrogated Aurora-A coupled pro-survival phosphoinositide-3-kinase (PI3K)/Akt signalling cascades. Further, the role of hesperidin over apoptosis and mammalian target of rapamycin (mTOR) mediated autophagic responses were studied. Azoxymethane (AOM) induced mouse model of colon carcinogenesis was involved in this study. Hesperidin treatment was provided either in initiation/post-initiation mode respectively. Hesperidin significantly altered AOM mediated anti-apoptotic scenario by modulating Bax/Bcl-2 ratio together with enhanced cytochrome-c release and caspase-3, 9 activations. In addition, hesperidin enhanced p53-p21 axis with concomitant decrease in cell cycle regulator. Hesperidin treatment caused significant up-regulation of tumour suppressor phosphatase and tensin homologue (PTEN) with a reduction in the expression of AOM mediated p-PI3K and p-Akt. Additionally, hesperidin administration exhibited inhibition against p-mTOR expression which in turn led to stimulation of autophagic markers Beclin-1 and LC3-II. Aurora-A an upstream regulator of PI3K/Akt pathway was significantly inhibited by hesperidin. Furthermore, hesperidin administration restored glycogen synthase kinase-3 beta (GSK-3ß) activity which in turn prevented the accumulation of oncoproteins ß-catenin, c-jun and c-myc. Taken together, hesperidin supplementation initiated apoptosis via targeted inhibition of constitutively activated Aurora-A mediated PI3K/Akt/GSK-3ß and mTOR pathways coupled with autophagic stimulation against AOM induced colon carcinogenesis.

Berberine attenuates bleomycin induced pulmonary toxicity and fibrosis via suppressing NF-κB dependant TGF-ß activation: a biphasic experimental study.

Idiopathic pulmonary fibrosis (IPF) is a progressive, debilitating and fatal lung disorder with high mortality rate. Unfortunately, to date the treatment for IPF remains unsatisfying and in severe cases lung transplantations are performed as a therapeutic measure. Thus, it becomes great interest to find novel agents to treat IPF. Berberine, a plant alkaloid known for its broad pharmacological activities remains a remedy against multiple diseases. This study was hypothesized to investigate the antifibrotic potential of berberine against bleomycin-induced lung injury and fibrosis, a tentative animal model. Male wistar rats were subjected to single intratracheal instillation of 2.5 U/kg of bleomycin on day 0. Berberine treatments were either provided in preventive or therapeutic mode respectively. Berberine administration significantly ameliorated the bleomycin mediated histological alterations and reduced the inflammatory cell infiltrate in BALF. Berberine significantly blocked collagen accumulations with parallel reduction in the hydroxyproline level. The immunological sign of bleomycin stimulated mast cell deposition and histamine release were considerably reduced by berberine. Berberine enhanced the antioxidant status, through upregulating the redox sensing transcription factor nuclear factor E2-related factor 2 (Nrf2). Berberine inhibited the bleomycin mediated activation of inflammatory mediator nuclear factor kappa B (NF-κB) and suppressed its downstream target inducible nitric oxide synthase (iNOS). Strikingly, berberine exhibited target attenuation of tumor necrosis factor alpha (TNF-α) and key pro-fibrotic mediator, transforming growth factor beta 1 (TGF-ß1). Taken together, this study reveals the beneficial effects of berberine against bleomycin mediated fibrotic challenge through activating Nrf2 and suppressing NF-κB dependent inflammatory and TGF-ß1 mediated fibrotic events.

Hesperidin alleviates oxidative stress and downregulates the expressions of proliferative and inflammatory markers in azoxymethane-induced experimental colon carcinogenesis in mice.

OBJECTIVE: Colon cancer is a common malignant neoplasm causing huge morbidity and mortality worldwide. Current therapeutic interventions are unsatisfying, which necessitates novel chemopreventive strategies. The present study was intended to elucidate the chemopreventive efficacy of hesperidin against azoxymethane (AOM)-induced mouse colon carcinogenesis. MATERIALS AND METHODS: Swiss albino mice were subjected to intraperitoneal injections of AOM once a week for 3 consecutive weeks. Hesperidin treatments were provided in the initiation or post-initiation phases. The number and multiplicity of aberrant crypt foci (ACF), tumor incidence and antioxidant status were determined. Histopathological analyses, proliferating cell nuclear antigen (PCNA) index and modulations in the expression of inflammatory markers such as nuclear factor kappa B (NF-κB), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were studied. RESULTS: Hesperidin treatments significantly inhibited the number and multiplicities of AOM-induced ACF and tumor incidence. Hesperidin reduced oxidative stress parameters and enhanced antioxidant status. A marked decrease in the PCNA index was evident on hesperidin administration. Hesperidin treatments caused a prominent downregulation of NF-κB and its target molecules iNOS and COX-2, thereby combating inflammation. CONCLUSION: This study proves the chemopreventive efficacy of hesperidin against the deleterious traits of colon carcinogenesis including accelerated proliferation, inflammation and persistent oxidative stress.