Enhancing the chemosensitivity of HepG2 cells towards cisplatin by organoselenium pseudopeptides.

Despite all recent advances in the treatment of hepatocellular carcinoma (HCC), chemotherapy resistance still represents a major challenge in its successful clinical management. Chemo-sensitization offers an attractive strategy to counter drug resistance. Herein we report the identification of novel organoselenium-based pseudopeptides as promising highly effective chemo-sensitizers in treating HCC with cisplatin. A series of functionalized pseudopeptide- (5-9 and 17-19), peptidomimetic- (10-12 and 20-23), and tetrazole-based (13-16 and 24-27) organoselenium compounds were synthesized via isonitrile-based multicomponent reactions from two novel selenium-containing isocyanides. All compounds were evaluated for their cytotoxicity against HepG2 and the non-cytotoxic doses were used to restor the sensitivity of the cells to cisplatin. New organoselenium compounds (7, 9, 15, or 23) led to an effective chemo-sensitization of HepG2 cells towards cisplatin (up-to 27-fold). Cell cycle studies indicate that the most potent peptidomimetic diselenide 23 arrested cells at the S phase and induced apoptosis via ROS modulation.

Sestrin-3 modulation is essential for therapeutic efficacy of cucurbitacin B in lung cancer cells.

Many purified compounds from dietary sources have been investigated for their anticancer activities. The main issue with most agents is their effectiveness at high doses which generally could not be delivered to humans through dietary consumption. Here, we observed that cucurbitacin B, a tetracyclic triterpenoid present in pumpkins, gourds and squashes, exhibits antiproliferative effects on human non-small cell lung cancer (NSCLC) cells at nanomolar concentrations. Treatment with cucurbitacin B (0.2-0.6 µM; 24 h) was found to result in decrease in the viability of EGFR-wild type (A549 and H1792) and EGFR-mutant lung cancer cells (H1650 and H1975) and reduction in cell-colonies but had only minimal effect on normal human bronchial epithelial cells. Treatment with cucurbitacin B also caused inhibition of PI3K/mTOR and signal transducer and activator of transcription (STAT)-3 signaling along with simultaneous activation of AMPKα levels in both EGFR-wild type and EGFR-mutant lung cancer cells. Cucurbitacin B caused specific increase in the protein and mRNA expression of sestrin-3 in EGFR-mutant lung cancer cells, but not in EGFR-wild type cells. Treatment with cucurbitacin B to sestrin-3 siRNA treated EGFR-mutant cells further amplified the decrease in cell-viability and caused more sustained G2-phase cell cycle arrest, suggesting that these effects are mediated partly through sestrin-3. We also found that sestrin-3 has a role in the induction of apoptosis by cucurbitacin B in both EGFR-wild type and EGFR-mutant lung cancer cells. These findings suggest novel mechanism by the modulation of sestrin-3 for the action of cucurbitacin B and suggest that it could be developed as an agent for therapy of NSCLC.

Oral administration of naturally occurring chitosan-based nanoformulated green tea polyphenol EGCG effectively inhibits prostate cancer cell growth in a xenograft model.

In preclinical animal models, several phytochemicals have shown excellent potential to be used as effective agents in preventing and treating many cancers. However, the limited bioavailability of active agents could be one reason for their restricted usefulness for human consumption. To overcome this limitation, we recently introduced the concept of nanochemoprevention by encapsulating useful bioactive food components for their slow and sustained release. Here, we report the synthesis, characterization and efficacy assessment of a nanotechnology-based oral formulation of chitosan nanoparticles encapsulating epigallocatechin-3-gallate (Chit-nanoEGCG) for the treatment of prostate cancer (PCa) in a preclinical setting. Chit-nanoEGCG with a size of <200nm diameter and encapsulating EGCG as determined by dynamic light scattering and transmission electron microscope showed slow release of EGCG in simulated gastric juice acidic pH and faster release in simulated intestinal fluid. The antitumor efficacy of Chit-nanoEGCG was assessed in subcutaneously implanted 22Rν1 tumor xenografts in athymic nude mice. Treatment with Chit-nanoEGCG resulted in significant inhibition of tumor growth and secreted prostate-specific antigen levels compared with EGCG and control groups. In tumor tissues of mice treated with Chit-nanoEGCG, compared with groups treated with EGCG and controls, there was significant (i) induction of poly (ADP-ribose) polymerases cleavage, (ii) increase in the protein expression of Bax with concomitant decrease in Bcl-2, (iii) activation of caspases and (iv) reduction in Ki-67 and proliferating cell nuclear antigen. Through this study, we propose a novel preventive and therapeutic modality for PCa using EGCG that addresses issues related to bioavailability.

Excellent anti-proliferative and pro-apoptotic effects of (-)-epigallocatechin-3-gallate encapsulated in chitosan nanoparticles on human melanoma cell growth both in vitro and in vivo.

Earlier we demonstrated the anti-proliferative and pro-apoptotic effects of green tea polyphenol epigallocatechin-3-gallate (EGCG) on human melanoma cells (Int J Cancer. 2005; 114(4): 513-21). The doses used in this study were not physiologically attainable and for chemoprevention the preferred route of administration is oral consumption. To overcome these shortcomings, and taking advantage of our novel concept of nanochemoprevention (Cancer Res. 2009;69(5):1712-6), we developed a nanotechnology based oral delivery system to encapsulate EGCG. Here, using human melanoma Mel 928 cells we demonstrate 8-fold dose advantage of this nanoformulation over native EGCG. Further, nano-EGCG treated cells showed marked induction of apoptosis and cell cycle inhibition along with the growth of Mel 928 tumor xenograft. Nano-EGCG also inhibited proliferation (Ki-67 and PCNA) and induced apoptosis (Bax, PARP) in tumors harvested from the treated mice. These observations warrant further in vivo efficacy studies of nano-EGCG in robust animal models of human melanoma. FROM THE CLINICAL EDITOR: This team of investigators developed a nanotechnology based oral delivery system to encapsulate EGCG, a green tea-derived polyphenol in chitosan nanoparticles. Using human melanoma cells, an eight-fold dose advantage was demonstrated over native EGCG, leading to measurable apoptosis induction and proliferation inhibition, warranting further in vivo investigations.

Melatonin protected against kidney impairment induced by 5-fluorouracil in mice.

The utility of 5-fluorouracil (5-FU) as a successful chemotherapeutic drug for several cancers is limited by the induction of kidney injury and dysfunction due to redox imbalance, inflammation, and apoptosis. Meanwhile, melatonin (MLT) is a potent antioxidant and anti-inflammatory natural compound with a wide safety range. The current study aimed to investigate MLT's protective effect against 5-FU-induced kidney impairment. Male mice were given multiple doses of 5-FU at 25 and 100 mg/kg, as well as MLT at 20 mg/kg. MLT treatment alleviated the toxic effect of 5-FU by normalizing blood urea and creatinine levels and preserving the histological structure, indicating MLT's nephroprotective ability. This is accompanied by body weight maintenance, an increase in survival percentage, and preserved hematological parameters in comparison to the 5-FU-treated mice. MLT's renoprotective effect was explained by improvements in C-reactive protein, IL-6, and caspase-3 in kidney tissue, indicating MLT's anti-inflammatory and antiapoptotic ability. Furthermore, MLT inhibited 5-FU-induced lipid peroxidation by maintaining the activity of superoxide dismutase and catalase, as well as glutathione levels in kidney tissue from mice treated with both doses of 5-FU. The current findings show that MLT has a novel protective effect against 5-FU-induced renal injury and renal impairment.

ß-caryophyllene oxide induces apoptosis and inhibits proliferation of A549 lung cancer cells.

One of the most common cancers that result in death is lung cancer. There is new hope in the fight against lung cancer thanks to the chemopreventive properties of natural dietary substances like ß-caryophyllene oxide (CPO), and research is currently being done to test this theory. CPO, a sesquiterpene isolated from medicinal plant essential oils, inhibits carcinogenesis and has been effective in treating many cancers. This study examined how CPO affected proliferation of human lung cancer A549 cells. CPO was found to have an inhibitory concentration (IC50) of 124.1 g/ml. The proliferative markers Ki67 and PCNA were significantly inhibited after cells were treated with CPO at a concentration of 50 g/ml compared to controls. CPO-treated cells expressed more P21, P53, and DNA strand breaks than controls. This was accompanied by a significant cell cycle arrest in the S and G2/M phases. In treated A549 cells, this was also associated with a significant induction of apoptosis, as shown by the upregulation of the expression of caspases 3, 7, and 9, as well as Bax, and the downregulation of Bcl-2. Furthermore, the redox status of treated A549 cells revealed a marked rise in GSH and GPx activity levels and a decline in 4-HNE levels, indicating low oxidative stress following CPO treatment of A549 cells. In conclusion, cell cycle arrest and apoptosis, which are unrelated to oxidative stress, were the mechanisms by which CPO reduced cancer lung cell growth. This finding might be a potential therapeutic target for the treatment of lung cancer. Hypothetical scheme of CPO anticancer effects (mechanism of signaling) in A549 cells; in vitro. CPO treatment increases expression of p21, p53 and DNA fragmentation. These events cause arrest of cell cycle which was associated with significant induction in apoptosis via increase expression of caspases (-3,-7,-9), and Bax and downregulation of Bcl-2.

Melatonin protects the heart and pancreas by improving glucose homeostasis, oxidative stress, inflammation and apoptosis in T2DM-induced rats.

Cardiomyopathy and pancreatic injury are health issues associated with type 2 diabetes mellitus (T2DM) and are characterized by elevated oxidative stress, inflammation and apoptosis. Melatonin (MLT) is a hormone with multifunctional antioxidant activity. The protective effects of MLT on the heart and pancreas during the early development of diabetic cardiomyopathy and pancreatic injury were investigated in male Wistar rats with T2DM. MLT (10 mg/kg) was administered daily by gavage for 15 days after diabetic induction. Treatment of diabetic rats with MLT significantly normalized the levels of serum glucose, HbA1-c, and the lipid profile and improved the insulin levels and insulin resistance compared with diabetic rats, affirming its antidiabetic effect. MLT significantly prevented the development of oxidative stress and sustained the levels of glutathione and glutathione peroxidase activity in the heart and pancreas of diabetic animals, indicating its antioxidant capacity. Additionally, MLT prevented the increase in proinflammatory cytokines and expression of Bax, caspase-3 and P53. Furthermore, MLT enhanced the anti-inflammatory cytokine IL-10 and antiapoptotic protein Bcl-2. MLT controlled the levels of troponin T and creatine kinase-MB and lactate dehydrogenase activity, indicating its anti-inflammatory and antiapoptotic effects. Histological examinations confirmed the protective effects of MLT on T2DM-induced injury in the myocardium, pancreas and islets of Langerhans. In conclusion, the protective effects of melatonin on the heart and pancreas during the early development of T2DM are attributed to its antihyperglycemic, antilipidemic and antioxidant influences as well as its remarkable anti-inflammatory and antiapoptotic properties.

Melatonin exerts a neuroprotective effect against γ-radiation-induced brain injury in the rat through the modulation of neurotransmitters, inflammatory cytokines, oxidative stress, and apoptosis.

The current study aimed to investigate the ameliorative effect of melatonin (MLT) against brain injury in rats undergoing whole-body exposure to γ-radiation. Male Wistar rats were whole-body exposed to 4-Gy γ-radiation from a cesium-137 source. MLT (10 mg/kg) was orally administrated 30 minutes before irradiation and continued once daily for 1 and 7 days after exposure. In the irradiated rats, the plasma levels of glutamate were increased, while the gamma-aminobutyric acid (GABA) levels were decreased, and MLT improved the disturbed glutamate and GABA levels. These effects paralleled an increase in pro-inflammatory cytokines (IL-1b, IL-6, and TNF-a) and C-reactive protein as well as a decrease in IL-10 in the plasma of the irradiated rats. MLT treatment markedly reduced these effects, indicating its anti-inflammatory impact. Immunohistochemical studies demonstrated a remarkable upregulation of caspase-3 and P53 expression, indicating the increased apoptosis in the brain of irradiated rats. MLT significantly downregulated the expression of these parameters compared with that in the irradiated rats, indicating its anti-apoptotic effect. Oxidative stress is developed in the brain as evidenced by increased levels of malondialdehyde; decreased activities of superoxide dismutase, catalase, and glutathione peroxidase; and decreased content of glutathione in the brain. MLT remarkably ameliorated the development of oxidative stress in the brain of the irradiated rats indicating its antioxidant impact. The histopathological results were consistent with the biochemical and immunohistochemical results and showed that MLT remarkably protected the histological structure of brain tissue compared with that in the irradiated rats. In conclusion, MLT showed potential neuroprotective properties by increasing the release of neurotransmitters, antioxidants, and anti-inflammatory factors and reducing pro-inflammatory cytokines and apoptosis in the brain of irradiated rats. MLT can be beneficial in clinical and occupational settings requiring radiation exposure; however, additional studies are required to elucidate its neuroprotective effect in humans.

Urea-functionalized organoselenium compounds as promising anti-HepG2 and apoptosis-inducing agents.

Hepatocellular carcinoma is a highly aggressive and difficult-to-treat type of cancer. Incorporating urea functionality into the backbone of organoselenium compounds is expected to develop promising chemotherapeutic leads against liver cancer. Methods: Urea-functionalized organoselenium compounds were synthesized in good yields, and their cytotoxicity was evaluated against HepG2 cells. Results: 1,1'-(Diselanediylbis(4,1-phenylene))bis(3-phenylurea) (14) exhibited efficient anti-HepG2 activity in sub-micromolar concentrations, with no toxicity to normal human skin fibroblasts. The molecular mechanisms of the diselenide-based urea 14 were evaluated using colony formation, wound healing, 3D spheroid invasion assays, cell cycle analysis and apoptosis induction. Its redox properties were also assessed by using different bioassays. Conclusion: Our study revealed promising anticancer, antimigratory and anti-invasiveness properties of 1,1'-(diselanediylbis(4,1-phenylene))bis(3-phenylurea) (14) against HepG2.

A novel kefir product (PFT) inhibits Ehrlich ascites carcinoma in mice via induction of apoptosis and immunomodulation.

BACKGROUND: The popularity of fermented foods such as kefir, kuniss, and tofu has been greatly increasing over the past several decades, and the ability of probiotic bacteria to exert anticancer effects has recently become the focus of research. While we have recently demonstrated the ability of the novel kefir product PFT (Probiotics Fermentation Technology) to exert anticancer effects in vitro, here we demonstrate its ability to inhibit Ehrlich ascites carcinoma (EAC) in mice. METHODS: Mice were inoculated intramuscularly with EAC cells to develop solid tumors. PFT was administered orally (2 g/kg/day) to mice 6 days/week, either 2 days before tumor cell inoculation or 9 days after inoculation to mice bearing solid tumors. Tumor growth, blood lymphocyte levels, cell cycle progression, apoptosis, apoptotic regulator expression, TNF-α expression, changes in mitochondrial membrane potential (MMP), PCNA, and CD4+ and CD8+ T cells in tumor cells were quantitatively evaluated by flow cytometry or RT-PCR. Further studies in vitro were carried out where EAC cells along with several other human cancer cell lines were cultured in the presence of PFT (0-5 mg/mL). Percent cell viability and IC50 was estimated by MTT assay. RESULTS: Our data shows that PFT exerts the following: 1) inhibition of tumor incidence and tumor growth; 2) inhibition of cellular proliferation via a marked decrease in the expression of tumor marker PCNA; 3) arrest of the tumor cell cycle in the sub-G0/G1 phase, signifying apoptosis; 4) induction of apoptosis in cancer cells via a mitochondrial-dependent pathway as indicated by the up-regulation of p53 expression, increased Bax/Bcl-2 ratio, decrease in the polarization of MMP, and caspase-3 activation; and 5) immunomodulation with an increase in the number of infiltrating CD4+ and CD8+ T cells and an enhancement of TNF-α expression within the tumor. CONCLUSIONS: PFT reduces tumor incidence and tumor growth in mice with EAC by inducing apoptosis in EAC cells via the mitochondrial-dependent pathway, suppressing cancer cell proliferation, and stimulating the immune system. PFT may be a useful agent for cancer prevention.