Kaempferol-Mediated Sensitization Enhances Chemotherapeutic Efficacy of Sorafenib Against Hepatocellular Carcinoma: An In Silico and In Vitro Approach

Purpose: Sorafenib is the sole FDA approved drug conventionally used for the treatment of advanced hepatocellular carcinoma (HCC). Despite of the beneficial use of sorafenib in the treatment of HCC, multidrug resistance still remains a challenge. HCC is inherently known as chemotherapy resistant tumor due to P-glycoprotein (P-gp)-mediated multidrug resistance. Methods: We studied the interaction energy of kaempferol with human multidrug resistance protein-1 (RCSB PDB ID: 2CBZ) using in silico method with the help of BIOVIA Discovery Studio. HepG2 and N1S1 liver cancer cell lines were treated in suitable cell culture media to evaluate the efficacy of kaempferol in chemo-sensitizing liver cancer cells towards the effect of sorafenib. Cell viability study was performed by MTT assay. Results: In silico analysis of kaempferol showed best docking score of 23.14 with Human Multi Drug Resistant Protein-1 (RCSB PDB ID: 2CBZ) compared with positive control verapamil. Inin-vitro condition, combination of sub-toxic concentrations of both kaempferol and sorafenib produced 50% cytotoxicity with concentration of 2.5 µM each which indicates that kaempferol has the ability to reverse the MDR by decreasing the over-expression of P-gp. Conclusion: Kaempferol is able to sensitize the HepG2 and N1S1 against the sub-toxic concentration of sorafenib. Hence, we consider that the efficacy of sorafenib chemotherapy can be enhanced by the significant approach of combining the sub-toxic concentrations of sorafenib with kaempferol. Thus, kaempferol can be used as a better candidate molecule along with sorafenib for enhancing its efficacy, if validated through preclinical studies.

Inevitable role of TGF-β1 in progression of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a major health concern and the most commonly diagnosed chronic liver manifestation among 25% worldwide population. Obesity, insulin resistance, accumulation of toxic lipid free radicals, generation of oxidative stress, overconsumption of fat containing dietary meals and lack of exercise are the paramount factors accountable for the development of NAFLD. During NAFLD, increased oxidative stress and production of enormous number of toxic free radicals activates a number of pro-inflammatory and inflammatory pathways. TGF-β signaling mechanisms play a central role in maintaining the normal homeostasis of liver. TGF-β1, one of the three isoforms of TGF-β family has significant role in different stages of chronic liver conditions. TGF-β1 promotes HSC activation and extracellular matrix production (ECM), which further contributes in the progression of NAFLD. In this review, we outline the role of TGF-β1 in different phases of progressive NAFLD along with the signaling mechanism.

Evaluation of uttroside B, a saponin from Solanum nigrum Linn, as a promising chemotherapeutic agent against hepatocellular carcinoma

We report, for the first time, the remarkable efficacy of uttroside B, a potent saponin from Solanum nigrum Linn, against liver cancer. The compound has been isolated and characterized from the leaves of Solanum nigrum Linn, a plant widely used in traditional medicine and is a rich resource of several anticancer molecules. Uttroside B, that comprises of β-D-glucopyranosyl unit at C-26 of the furostanol and β-lycotetraosyl unit at C-3, is ten times more cytotoxic to the liver cancer cell line, HepG2 (IC50: 0.5 μM) than sorafenib (IC50: 5.8 μM), the only FDA-approved drug for liver cancer. Moreover, it induces cytotoxicity in all liver cancer cell lines, irrespective of their HBV status, while being non-toxic to normal immortalized hepatocytes. It induces apoptosis in HepG2 cells by down-regulating mainly the activation of MAPK and mTOR pathways. The drastic reduction in HepG2-xenograft tumor size achieved by uttroside B in NOD-SCID mice and substantiation of its biological safety through both acute and chronic toxicity studies in Swiss albino mice warrants clinical validation of the molecule against hepatic cancer, for which, the chemotherapeutic armamentarium currently has limited weapons.

In Vitro Evaluation of the Antioxidant, 3,5-Dihydroxy-4-ethyl-trans-stilbene (DETS) Isolated from Bacillus cereus as a Potent Candidate against Malignant Melanoma

3,5-dihydroxy Q1 -4-ethyl-trans-stilbene (DETS) is a natural stilbene, which was first identified as bioactive bacterial secondary metabolite isolated from Bacillus cereus associated with a rhabditid entomopathogenic nematode. The present study was intended to investigate the antioxidant and anticancer activity of this compound in vitro. Antioxidant activity was investigated by assaying DPPH free radical scavenging, superoxide radical-(O2..) scavenging, hydroxyl radical scavenging and metal chelating activity, which proved that the compound is a powerful antioxidant. The metal chelating activity of DETS was higher than butylated hydroxyanisol (BHA) and gallic acid, two well-known antioxidants. As the molecule exhibited strong antioxidant potential, it was further evaluated for cytotoxic activity toward five cancer cells of various origins. Since the compound has a strong structural similarity with resveratrol (trans- 3,4,5-trihydroxystilbene), a well-studied chemopreventive polyphenolic antioxidant, its anticancer activity was compared with that of resveratrol. Among the five cancer cells studied, the compound showed maximum cytotoxicity toward the human melanoma cell line, [A375, IC50: 24.01 μM] followed by cervical [HeLa-46.17 μM], colon [SW480- 47.28 μM], liver [HepG2- 69.56 μM] and breast [MCF-7- 84.31 μM] cancer cells. A375 was much more sensitive to DETS compared to the non-melanoma cell line, A431, in which the IC50 of the compound was more than double (49.60 μM). In the present study, the anticancer activity of DETS against melanoma was confirmed by various apoptosis assays. We also observed that DETS, like resveratrol, down-regulates the expression status of major molecules contributing to melanoma progression, such as BRAF, β-catenin and Brn-2, all of which converge in MITF-M, the master regulator of melanoma signaling. The regulatory role of MITF-M in DETS-induced cytotoxicity in melanoma cells was confirmed by comparing the cytotoxicity of DETS in A375 cells (IC50-24.01 μM), with that in SK-MEL-2 (IC50-67.6 μM), another melanoma cells which highly over-express MITF-M. The compound arrests the cells at S-G2 transition state of the cell cycle, as resveratrol. Our results indicate that DETS is a powerful antioxidant, having anticancer efficacy comparable with that of resveratrol, and is a potential candidate to be explored by in vivo studies and in-depth mechanistic evaluation. To our knowledge, this is the first report on the antioxidant and anticancer properties of DETS.

DW-F5: A novel formulation against malignant melanoma from Wrightia tinctoria

Wrightia tinctoria is a constituent of several ayurvedic preparations against skin disorders including psoriasis and herpes, though not yet has been explored for anticancer potential. Herein, for the first time, we report the significant anticancer properties of a semi-purified fraction, DW-F5, from the dichloromethane extract of W. tinctoria leaves against malignant melanoma. DW-F5 exhibited anti-melanoma activities, preventing metastasis and angiogenesis in NOD-SCID mice, while being non-toxic in vivo. The major pathways in melanoma signaling mediated through BRAF, WNT/β-catenin and Akt-NF-κB converging in MITF-M, the master regulator of melanomagenesis, were inhibited by DW-F5, leading to complete abolition of MITF-M. Purification of DW-F5 led to the isolation of two cytotoxic components, one being tryptanthrin and the other being an unidentified aliphatic fraction. The overall study predicts Wrightia tinctoria as a candidate plant to be further explored for anticancer properties and DW-F5 as a forthcoming drug formulation to be evaluated as a chemotherapeutic agent against malignant melanoma.

Kaempferide, the most active among the four flavonoids isolated and characterized from Chromolaena odorata, induces apoptosis in cervical cancer cells while being pharmacologically safe

We report the isolation and characterization of four compounds from a cytotoxic fraction F-17, isolated from the DCM extract of C. odorata by bioactivity guided fractionation.

[6]-Gingerol induces caspase-dependent apoptosis and prevents PMA-induced proliferation in colon cancer cells by inhibiting MAPK/AP-1 signaling

We report mechanism-based evidence for the anticancer and chemopreventive efficacy of [6]-gingerol, the major active principle of the medicinal plant, Ginger (Zingiber officinale), in colon cancer cells. The compound was evaluated in two human colon cancer cell lines for its cytotoxic effect and the most sensitive cell line, SW-480, was selected for the mechanistic evaluation of its anticancer and chemopreventive efficacy. The non-toxic nature of [6]-gingerol was confirmed by viability assays on rapidly dividing normal mouse colon cells. [6]-gingerol inhibited cell proliferation and induced apoptosis as evidenced by externalization of phosphatidyl serine in SW-480, while the normal colon cells were unaffected. Sensitivity to [6]-gingerol in SW-480 cells was associated with activation of caspases 8, 9, 3 &7 and cleavage of PARP, which attests induction of apoptotic cell death. Mechanistically, [6]-gingerol down-regulated Phorbol Myristate Acetate (PMA) induced phosphorylation of ERK1/2 and JNK MAP kinases and activation of AP-1 transcription factor, but had only little effects on phosphorylation of p38 MAP kinase and activation of NF-kappa B. Additionally, it complemented the inhibitors of either ERK1/2 or JNK MAP kinase in bringing down the PMA-induced cell proliferation in SW-480 cells. We report the inhibition of ERK1/2/JNK/AP-1 pathway as a possible mechanism behind the anticancer as well as chemopreventive efficacy of [6]-gingerol against colon cancer.

Cytotoxicity studies of semi-synthetic derivatives of theveside derived from the aqueous extract of leaves of 'suicide tree' Cerbera odollam

We report the isolation of two known iridoid glucosides theviridoside (1) and theveside (2) from the aqueous extract of leaves of Cerbera odollam and semi-synthetic derivatisation of theveside prepared in a single step under protection group-free conditions. Derivatives 2a-j were evaluated for cytotoxicity towards five human cancer cell lines of different origins, namely SKBR3 (breast), HeLa (cervical), A375 (skin), HepG2 (liver) and HCT-116 (colon), and IC50 values were determined. Derivatives 2b and 2h exhibited moderate cytotoxicity against HCT-116 and A375 cell lines, respectively.

Anti-inflammatory activity of mirabilis jalapa linn. Leaves

Mirabilis Jalapa Linn. is a widely used traditional medicine in many parts of the world for the treatment of various diseases viz. virus inhibitory activity, anti tumour activity. It is claimed in traditional medicine that the leaves of the plant are used in the treatment of inflammation. In the present study, the total alcoholic extract and successive petroleum ether fractions of leaves of Mirabilis Jalapa Linn were screened for its anti-inflammatory activity using carageenan induced rat paw edema and cotton pellet induced granuloma models. The total alcoholic extract at the dose of 300 mg/kg p.o and successive petroleum ether fraction at the dose of 200 mg/kg exhibited significant anti-inflammatory activity in carrageenan induced paw edema model (p<0.01). In cotton pellet granuloma model, the total alcoholic extract at the dose of 300 mg/kg and successive petroleum ether fraction at the dose of 200 mg/kg inhibited granuloma formation significantly (p<0.05) indicating that both test samples inhibit the increase in number of fibroblasts and synthesis of collagen and mucopolysaccharides during granuloma tissue formation during the chronic inflammation. These experimental results have established a pharmacological evidence for the folklore claim of the drug to be used as an anti inflammatory agent.