Study to evaluate molecular mechanics behind synergistic chemo-preventive effects of curcumin and resveratrol during lung carcinogenesis

Unveiling the potential effects of resveratrol in lung cancer treatment: Mechanisms and nanoparticle-based drug delivery strategies

Lung cancer ranks among the most prevalent forms of cancer and remains a significant factor in cancer-related mortality across the world. It poses significant challenges to healthcare systems and society as a whole due to its high incidence, mortality rates, and late-stage diagnosis. Resveratrol (RV), a natural compound found in various plants, has shown potential as a nanomedicine for lung cancer treatment. RV has varied effects on cancer cells, including promoting apoptosis by increasing pro-apoptotic proteins (Bax and Bak) and decreasing anti-apoptotic proteins (Bcl-2). It also hinders cell proliferation by influencing important signaling pathways (MAPK, mTOR, PI3K/Akt, and Wnt/β-catenin) that govern cancer progression. In addition, RV acts as a potent antioxidant, diminishing oxidative stress and safeguarding cells against DNA damage. However, using RV alone in cancer treatment has drawbacks, such as low bioavailability, lack of targeting ability, and susceptibility to degradation. In contrast, nanoparticle-based delivery systems address these limitations and hold promise for improving treatment outcomes in lung cancer; nanoparticle formulations of RV offer advantages such as improved drug delivery, increased stability, controlled release, and targeted delivery to lung cancer cells. This article will provide an overview of lung cancer, explore the potential of RV as a therapeutic agent, discuss the benefits and challenges of nanoparticle-based drug delivery, and highlight the promise of RV nanoparticles for cancer treatment, including lung cancer. By optimizing these systems for clinical application, future studies aim to enhance overall treatment outcomes and improve the prognosis for lung cancer patients.

Advanced effect of curcumin and resveratrol on mitigating hepatic steatosis in metabolic associated fatty liver disease via the PI3K/AKT/mTOR and HIF-1/VEGF cascade

Metabolic associated fatty liver disease (MAFLD) is the most common chronic liver disease that has no viable treatment. Curcumin (Cur) and resveratrol (Res) are two natural products that have been studied for their potential to ameliorate MAFLD. However, while these compounds have been investigated individually, their combined use and the potential for a synergistic or augmented effect remain unexplored. This study aims to investigate the effect of curcumin (Cur) and resveratrol (Res) as a potential combination therapy on MAFLD. Cur, Res and Cur+Res were tested in palmitic acid (PA)-induced-HepG2 cells. MAFLD model was established using Goto-Kakizaki rats. The animals were treated with vehicle control (model group), Cur (150 mg/kg), Res (150 mg/kg), Cur+Res (150 mg/kg, 8:2, w/w), or metformin (Met, positive control, 400 mg/kg/day) via oral gavage for 4 weeks. Wistar rats were used as the control group. Network pharmacology was conducted to elucidate the molecular actions of Cur and Res, followed by q-PCR and immunoblotting in vivo. Cur+Res exhibited synergistic effects in reducing triglyceride, total cholesterol and lipid accumulation in PA-induced HepG2 cells. The combination also markedly attenuated hepatic steatosis in the MAFLD rats. Network pharmacology illustrated that the interaction of Cur and Res was associated with the modulation of multiple molecular targets associated with the PI3K/AKT/mTOR and HIF-1 signaling pathways. Experimental results confirmed that Cur+Res nomalised the gene targets and protein expressions in the PI3K/AKT/mTOR and HIF-1 signaling pathways, including PI3K, mTOR, STAT-3, HIF-1α, and VEGF. The present study demonstrated an advanced effect of Cur and Res in combination to attenuate MAFLD, and the mechanism is at least partly associated with the modulation of the PI3K/AKT/mTOR and HIF-1 signaling pathways.

Physicochemical Characterization and Evaluation of Gastrointestinal In Vitro Behavior of Alginate-Based Microbeads with Encapsulated Grape Pomace Extracts

Grape pomace is a byproduct of wineries and a rich source of phenolic compounds that can exert multiple pharmacological effects when consumed and enter the intestine where they can then be absorbed. Phenolic compounds are susceptible to degradation and interaction with other food constituents during digestion, and encapsulation may be a useful technique for protecting phenolic bioactivity and controlling its release. Therefore, the behavior of phenolic-rich grape pomace extracts encapsulated by the ionic gelation method, using a natural coating (sodium alginate, gum arabic, gelatin, and chitosan), was observed during simulated digestion in vitro. The best encapsulation efficiency (69.27%) was obtained with alginate hydrogels. The physicochemical properties of the microbeads were influenced by the coatings used. Scanning electron microscopy showed that drying had the least effect on the surface area of the chitosan-coated microbeads. A structural analysis showed that the structure of the extract changed from crystalline to amorphous after encapsulation. The phenolic compounds were released from the microbeads by Fickian diffusion, which is best described by the Korsmeyer-Peppas model among the four models tested. The obtained results can be used as a predictive tool for the preparation of microbeads containing natural bioactive compounds that could be useful for the development of food supplements.

Co-administration of curcumin with other phytochemicals improves anticancer activity by regulating multiple molecular targets

Natural plant phytochemicals are effective against different types of diseases, including cancer. Curcumin, a powerful herbal polyphenol, exerts inhibitory effects on cancer cell proliferation, angiogenesis, invasion, and metastasis through interaction with different molecular targets. However, the clinical use of curcumin is limited due to poor solubility in water and metabolism in the liver and intestine. The synergistic effects of curcumin with some phytochemicals such as resveratrol, quercetin, epigallocatechin-3-gallate, and piperine can improve its clinical efficacy in cancer treatment. The present review specifically focuses on anticancer mechanisms related to the co-administration of curcumin with other phytochemicals, including resveratrol, quercetin, epigallocatechin-3-gallate, and piperine. According to the molecular evidence, the phytochemical combinations exert synergistic effects on suppressing cell proliferation, reducing cellular invasion, and inducing apoptosis and cell cycle arrest. This review also emphasizes the significance of the co-delivery vehicles-based nanoparticles of such bioactive phytochemicals that could improve their bioavailability and reduce their systemic dose. Further high-quality studies are needed to firmly establish the clinical efficacy of the phytochemical combinations.

Pro-Apoptotic and Anti-Cancer Activity of the Vernonanthura Nudiflora Hydroethanolic Extract

The mitochondrial voltage-dependent anion channel 1 (VDAC1) protein is involved in several essential cancer hallmarks, including energy and metabolism reprogramming and apoptotic cell death evasion. In this study, we demonstrated the ability of hydroethanolic extracts from three different plants, Vernonanthura nudiflora (Vern), Baccharis trimera (Bac), and Plantago major (Pla), to induce cell death. We focused on the most active Vern extract. We demonstrated that it activates multiple pathways that lead to impaired cell energy and metabolism homeostasis, elevated ROS production, increased intracellular Ca²⁺, and mitochondria-mediated apoptosis. The massive cell death generated by this plant extract's active compounds involves the induction of VDAC1 overexpression and oligomerization and, thereby, apoptosis. Gas chromatography of the hydroethanolic plant extract identified dozens of compounds, including phytol and ethyl linoleate, with the former producing similar effects as the Vern hydroethanolic extract but at 10-fold higher concentrations than those found in the extract. In a xenograft glioblastoma mouse model, both the Vern extract and phytol strongly inhibited tumor growth and cell proliferation and induced massive tumor cell death, including of cancer stem cells, inhibiting angiogenesis and modulating the tumor microenvironment. Taken together, the multiple effects of Vern extract make it a promising potential cancer therapeutic.

Protective role of AKBA against benzo(a)pyrene-induced lung carcinogenesis by modulating biotransformation enzymes and oxidative stress

The present study was designed to explore the chemopreventive potential of 3-acetyl-11-keto-β-boswellic acid (AKBA) during the initiation and promotion stage of lung carcinogenesis induced by benzo(a)pyrene (BaP) in female Sprague Dawley rats. BaP was administered at a dose level of 50 mg/kg b.wt. twice a week orally in olive oil for 4 weeks. AKBA administration was started 4 weeks before BaP treatment and continued for another 8 weeks at a dose level of 50 mg/kg b.wt. orally in olive oil three times a week. BaP treatment showed significantly increased in the activities of Phase I biotransformation enzymes (Cytochrome P₄₅₀ , b₅ , and aryl hydrocarbon hydrolase) and inhibited the activity of Phase II enzyme (glutathione-S-transferase). Also, a significant elevation in oxidative stress biomarkers lipid peroxidation, reactive oxygen species, and protein carbonyl content concentration. Further, an appreciable decrease was observed in the activities of endogenous antioxidant enzymes superoxide dismutase, CAT, GPx, GR, and a decline in nonenzymatic GSH levels. As a result of BaP induced oxidative stress, alteration in erythrocytes morphology was observed. Fourier transform infrared spectroscopy spectrum of lung tissue showed structural changes due to BaP exposure. Moreover, levels of tumor biomarkers such as total sialic acid, carcinoembryonic antigen, and alkaline phosphatase were significantly elevated following BaP treatment which was substantiated by alterations noticed in the histoarchitecture of lung tissue. Interestingly, AKBA administration to BaP treated rats appreciably alleviated the changes inflicted by BaP on various biochemical indices and histoarchitecture of lungs. Therefore, the study clearly revealed that AKBA by containing oxidative stress shall prove to be quite effective in providing chemoprevention against BaP induced lung carcinogenesis.

Curcumin and resveratrol inhibit chemoresistance in cisplatin-resistant epithelial ovarian cancer cells via targeting P13K pathway

BACKGROUND

The activation of the PI3K/AKT/mTOR pathway has been proved to be associated with survival as well as proliferation of various tumour cells in multiple cancer types, including epithelial ovarian cancer (EOC).

PURPOSE

Moreover, the activation of the PI3K/AKT/mTOR pathway is the key mechanism responsible for higher invasiveness and migratory capacities of ovarian cancer cells. Furthermore, PI3K is crucial for activation of the PI3K/AKT/mTOR pathway; therefore, its inhibition might be an effective strategy against cancer.

RESEARCH DESIGN

The combination approach is now an established strategy against cancer. So, the present study evaluated molecular mechanics behind the synergistic effects of curcumin and resveratrol along with cisplatin treatment on inhibition of the PI3K pathway in ovarian cancer cells.

RESULTS

The present study confirmed significant inhibition of the PI3K/AKT/mTOR pathway as observed by Matrigel invasion assay, Western blot expression of important molecular markers and apoptotic markers.

CONCLUSION

 The present study concludes that the combination of curcumin and resveratrol significantly sensitized the EOC cells to cisplatin treatment, thereby inhibiting chemoresistance in ovarian cancer cells by significant inhibition of the PI3K/AKT/mTOR pathway.

Curcumin and resveratrol inhibit chemoresistance in cisplatin-resistant epithelial ovarian cancer cells via targeting P13K pathway

BACKGROUND

The activation of the PI3K/AKT/mTOR pathway has been proved to be associated with survival as well as proliferation of various tumour cells in multiple cancer types, including epithelial ovarian cancer (EOC).

PURPOSE

Moreover, the activation of the PI3K/AKT/mTOR pathway is the key mechanism responsible for higher invasiveness and migratory capacities of ovarian cancer cells. Furthermore, PI3K is crucial for activation of the PI3K/AKT/mTOR pathway; therefore, its inhibition might be an effective strategy against cancer.

RESEARCH DESIGN

The combination approach is now an established strategy against cancer. So, the present study evaluated molecular mechanics behind the synergistic effects of curcumin and resveratrol along with cisplatin treatment on inhibition of the PI3K pathway in ovarian cancer cells.

RESULTS

The present study confirmed significant inhibition of the PI3K/AKT/mTOR pathway as observed by Matrigel invasion assay, Western blot expression of important molecular markers and apoptotic markers.

CONCLUSION

 The present study concludes that the combination of curcumin and resveratrol significantly sensitized the EOC cells to cisplatin treatment, thereby inhibiting chemoresistance in ovarian cancer cells by significant inhibition of the PI3K/AKT/mTOR pathway.

Resveratrol Promotes HIV-1 Tat Accumulation via AKT/FOXO1 Signaling Axis and Potentiates Vorinostat to Antagonize HIV-1 Latency

BACKGROUND

The latent reservoir of HIV-1 is a major barrier to achieving the eradication of HIV-1/AIDS. One strategy is termed "shock and kill", which aims to awaken the latent HIV-1 using latency reversing agents (LRAs) to replicate and produce HIV-1 particles. Subsequently, the host cells containing HIV-1 can be recognized and eliminated by the immune response and anti-retroviral therapy. Although many LRAs have been found and tested, their clinical trials were dissatisfactory.

OBJECTIVE

To aim of the study was to investigate how resveratrol reactivates silent HIV-1 transcription and assess if resveratrol could be a candidate drug for the "shock" phase in "shock and kill" strategy.

METHODS

We used established HIV-1 transcription cell models (HeLa-based NH1 and NH2 cells) and HIV-1 latent cell models (J-Lat A72 and Jurkat 2D10 cells). We performed resveratrol treatment on these cell lines and studied the mechanism of how resveratrol stimulates HIV-1 gene transcription. We also tested resveratrol's bioactivity on primary cells isolated from HIV-1 latent infected patients.

RESULTS

Resveratrol promoted HIV-1 Tat protein levels, and resveratrol-induced Tat promotion was found to be dependent on the AKT/FOXO1 signaling axis. Resveratrol could partially dissociate P-TEFb (Positive Transcription Elongation Factor b) from 7SK snRNP (7SK small nuclear Ribonucleoprotein) and promote Tat-SEC (Super Elongation Complex) interaction. Preclinical studies showed that resveratrol potentiated Vorinostat to awaken HIV-1 latency in HIV-1 latent infected cells isolated from patients.

CONCLUSION

We found a new mechanism of resveratrol stimulating the production of HIV-1. Resveratrol could be a promising candidate drug to eradicate HIV-1 reservoirs.

Plant-Derived Natural Products in Cancer Research: Extraction, Mechanism of Action, and Drug Formulation

Cancer is one of the main causes of death globally and considered as a major challenge for the public health system. The high toxicity and the lack of selectivity of conventional anticancer therapies make the search for alternative treatments a priority. In this review, we describe the main plant-derived natural products used as anticancer agents. Natural sources, extraction methods, anticancer mechanisms, clinical studies, and pharmaceutical formulation are discussed in this review. Studies covered by this review should provide a solid foundation for researchers and physicians to enhance basic and clinical research on developing alternative anticancer therapies.

Role of histone acetyltransferase inhibitors in cancer therapy

The development of cancer is a complex phenomenon driven by various extrinsic as well as intrinsic risk factors including epigenetic modifications. These post-translational modifications are encountered in diverse cancer cells and appear for a relatively short span of time. These changes can significantly affect various oncogenic genes and proteins involved in cancer initiation and progression. Histone lysine acetylation and deacetylation processes are controlled by two opposing classes of enzymes that modulate gene regulation either by adding an acetyl moiety on a histone lysine residue by histone lysine acetyltransferases (KATs) or via removing it by histone deacetylases (KDACs). Deregulated KAT activity has been implicated in the development of several diseases including cancer and can be targeted for the development of anti-neoplastic drugs. Here, we describe the predominant epigenetic changes that can affect key KAT superfamily members during carcinogenesis and briefly highlight the pharmacological potential of employing lysine acetyltransferase inhibitors (KATi) for cancer therapy.

Lagerstroemia speciosa (L.) Pers Leaf Extract Attenuates Lung Tumorigenesis via Alleviating Oxidative Stress, Inflammation and Apoptosis

One of the major etiological factors that account for lung cancer is tobacco use. Benzo(a)pyrene [B(a)P], one of the main constituents of tobacco smoke, has a key role in lung carcinogenesis. The present study was conducted to investigate the cytotoxicity of an aqueous ethanolic extract of Lagerstroemia speciosa (L.) Pers leaves (LLE) on human lung adenocarcinoma cells (A549), as well as its in vivo antitumor effect on a lung tumorigenesis mice model. Our results revealed that LLE possesses cytotoxic activity against the A549 cell line. Mice orally administered B(a)P (50 mg/kg body weight) showed an increase in relative lung weight with subsequent decrease in final body weight. Serum levels of tumor marker enzymes AHH, ADA and LDH and the inflammatory mediator NF-κB increased, while total antioxidant capacity (TAC) decreased. In addition, we observed the increased activity of metalloproteinases (MMP-2 and MMP-12) and levels of the tumor angiogenesis marker VEFG and the lipid peroxidation marker MDA, as well as decreased levels of the non-enzymatic antioxidant GSH and enzymatic antioxidants CAT and GSH-Px in lung tissues. Moreover, B(a)P administration up-regulated the expression of the COX-2 gene, pro-inflammatory cytokines TNF-α and IL-6, and an anti-apoptotic gene Bcl-2, and at the same time down-regulated expression of pro-apoptotic genes BAX and caspase-3 and the p53 gene. Pre- and post-treatment with LLE (250 mg/kg body weight) attenuated all these abnormalities. Histopathological observations verified the protective effect of LLE. Overall, the present data positively confirm the potent antitumor effect of L. speciosa leaves against lung tumorigenesis.

Evaluation of biophysical as well as biochemical potential of curcumin and resveratrol during prostate cancer

Purpose: The present study evaluated biochemical as well as biophysical mechanisms behind the synergistic effects of curcumin and resveratrol during prostate carcinogenesis.Methods: The rats were segregated into five groups that included normal control, 3,2'-dimethyl-4-aminobiphenyl (DMAB)treated, DMAB + curcumin treated, DMAB + resveratrol-treated and DMAB + curcumin + resveratrol-treated.Results: The DMAB treatment resulted in a significant increase in the levels of lipid peroxidation (LPO) in DMAB treated rats. Also, significant changes were recorded in the enzyme activities of both drug metabolising enzyme and antioxidant enzymes after DMAB treatment. Further, radiorespirometric studies showed a significant increase in the ¹⁴C-glucose turnover as well as ¹⁴C-glucose uptake in the prostate slices of DMAB treated rats. Moreover, a significant rise in cell proliferation was confirmed indirectly by enhanced uptake of ³H-thymidine in the prostate slices of DMAB treated rats. Interestingly, combined treatment of curcumin and resveratrol to DMAB treated animals resulted in a significant decrease in lipid peroxidation, ¹⁴C glucose uptakes/turnover and ³H-thymidine uptake in the DMAB treated rats. Besides this, curcumin and resveratrol in combination significantly modulated biochemical indices including drug-metabolising enzymes; antioxidant enzymes in DMBA treated rats.Conclusion: The study, therefore, concludes that the combination of curcumin and resveratrol holds strong modulatory potential against prostate carcinogenesis.

Potential of curcumin and resveratrol as biochemical and biophysical modulators during lung cancer in rats

The present study explored chemopreventive aspects of curcumin and resveratrol in the experimental model of lung carcinogenesis in rats. The main aim was to establish efficacy of combined phytochemicals treatment over individual treatments in rat cancer model. The study was performed in terms of both biophysical and biochemical parameters. The rats were segregated into five groups, which included normal control, benzo[a]pyrene (BP) treated, BP + curcumin treated, BP + resveratrol treated, and BP + curcumin + resveratrol treated groups. The results confirmed significant changes in the biochemical indices of the BP treated rats. Further, radiorespirometric studies showed significant rise in the ¹⁴C-glucose turnover and uptakes in BP treated rats. Also, a significant increase in the cell proliferation was noticed indirectly by recording uptakes of ³H-thymidine in the lung slices of BP treated rats. On the other hand, supplementation with curcumin and resveratrol in combination to BP treated rats significantly modulated both biophysical and biochemical indices. The histopathological studies also supported the efficacy of combined treatment of phytochemicals during lung carcinogenesis. The present study concluded that the combination of curcumin and resveratrol efficiently modulated lung carcinogenesis in rats.

The Role of Resveratrol in Cancer Therapy

Natural product compounds have recently attracted significant attention from the scientific community for their potent effects against inflammation-driven diseases, including cancer. A significant amount of research, including preclinical, clinical, and epidemiological studies, has indicated that dietary consumption of polyphenols, found at high levels in cereals, pulses, vegetables, and fruits, may prevent the evolution of an array of diseases, including cancer. Cancer development is a carefully orchestrated progression where normal cells acquires mutations in their genetic makeup, which cause the cells to continuously grow, colonize, and metastasize to other organs such as the liver, lungs, colon, and brain. Compounds that modulate these oncogenic processes can be considered as potential anti-cancer agents that may ultimately make it to clinical application. Resveratrol, a natural stilbene and a non-flavonoid polyphenol, is a phytoestrogen that possesses anti-oxidant, anti-inflammatory, cardioprotective, and anti-cancer properties. It has been reported that resveratrol can reverse multidrug resistance in cancer cells, and, when used in combination with clinically used drugs, it can sensitize cancer cells to standard chemotherapeutic agents. Several novel analogs of resveratrol have been developed with improved anti-cancer activity, bioavailability, and pharmacokinetic profile. The current focus of this review is resveratrol’s in vivo and in vitro effects in a variety of cancers, and intracellular molecular targets modulated by this polyphenol. This is also accompanied by a comprehensive update of the various clinical trials that have demonstrated it to be a promising therapeutic and chemopreventive agent.

Effects of Resveratrol against Lung Cancer: In Vitro and In Vivo Studies

Uncontrolled cell growth and resistance to apoptosis characterize cancer cells. These two main features are initiated in cancer cells through mutations in key signaling molecules, which regulate pathways that are directly involved in controlling cell proliferation and apoptosis. Resveratrol (RSV), a naturally occurring plant polyphenol, has been shown to have biological effects counteracting different diseases. It has been found to provide cardio-protective, neuro-protective, immuno-modulatory, and anti-cancer health benefits. RSV has been found to inhibit cancer cell proliferation, induce cell cycle arrest and apoptosis, and these anticancer effects may be due to its ability to modulate signaling molecules involved in these processes. The present review summarizes the existing in vitro and in vivo studies on resveratrol and its anti-lung cancer properties.

Stimulatory effects of curcumin and quercetin on posttranslational modifications of p53 during lung carcinogenesis

Lung cancer is responsible for increase in mortality due to cancer-related deaths, and new approaches are being explored for the betterment of the situation. In the present study, chemopreventive efficacy of curcumin and quercetin was investigated against benzo(a)pyrene (BP)-induced lung carcinogenesis. The mice were segregated into five groups, which included normal control, BP-treated, BP + curcumin-treated, BP + quercetin-treated, and BP + curcumin + quercetin-treated groups. The morphological and histological analyses of tumor nodules confirmed lung carcinogenesis22 weeks after weeks single intraperitoneal injection of BP at a dose of 100 mg/kg body weight to mice. Curcumin and quercetin when administered individually as well as in combination significantly elevated the expression of acetylated-p53, which was otherwise depressed due to BP treatment. Also, both the phytochemicals significantly reduced the BP-inflicted increased levels of phosphorylated-p53. Furthermore, observed increase in the number of apoptotic cells by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), assay and increased activities of caspase 3 and 9 confirmed the induction of apoptosis by curcumin and quercetin. Moreover, the histological slides also showed noticeable improvement in the histoarchitecture of lungs by phytochemicals. The present study concludes that prophylactic treatment with curcumin and quercetin induces apoptosis in the lungs by modulation of p53 posttranslational modifications.

Implications of Resveratrol on Glucose Uptake and Metabolism

Resveratrol—a polyphenol of natural origin—has been the object of massive research in the past decade because of its potential use in cancer therapy. However, resveratrol has shown an extensive range of cellular targets and effects, which hinders the use of the molecule for medical applications including cancer and type 2 diabetes. Here, we review the latest advances in understanding how resveratrol modulates glucose uptake, regulates cellular metabolism, and how this may be useful to improve current therapies. We discuss challenges and findings regarding the inhibition of glucose uptake by resveratrol and other polyphenols of similar chemical structure. We review alternatives that can be exploited to improve cancer therapies, including the use of other polyphenols, or the combination of resveratrol with other molecules and their impact on glucose homeostasis in cancer and diabetes.

Cancer Chemoprevention by Phytochemicals: Nature's Healing Touch

Phytochemicals are an important part of traditional medicine and have been investigated in detail for possible inclusion in modern medicine as well. These compounds often serve as the backbone for the synthesis of novel therapeutic agents. For many years, phytochemicals have demonstrated encouraging activity against various human cancer models in pre-clinical assays. Here, we discuss select phytochemicals—curcumin, epigallocatechin-3-gallate (EGCG), resveratrol, plumbagin and honokiol—in the context of their reported effects on the processes of inflammation and oxidative stress, which play a key role in tumorigenesis. We also discuss the emerging evidence on modulation of tumor microenvironment by these phytochemicals which can possibly define their cancer-specific action. Finally, we provide recent updates on how low bioavailability, a major concern with phytochemicals, is being circumvented and the general efficacy being improved, by synthesis of novel chemical analogs and nanoformulations.

Combination Approach: the Future of the War Against Cancer

Cancer remains one of the major health problems worldwide and is responsible for one in eight deaths. The worldwide research against cancer as well as genome wide association studies was successful in indentifying the loci associated with cancer but still a substantial amount of casualty remains unexplained. The reason being the cancer cell rapidly develops resistance against the chemotherapeutic or chemopreventive agent in use. Over the last decade, the thorough understanding of molecular and biochemical mechanisms of the carcinogenesis process lead to the rationale of combining anti-cancer agents (therapeutic as well as chemopreventive) to target multiple pathways. Scientists, the world over trying various combinations of chemotherapy, radiation therapy, chemopreventive agents, nanoparticles, etc., in order to specifically as well as efficiently target cancer cells. The present review article summarizes the recent advances in the combination approach against cancer in order to enhance efficacy of treatment with minimal side effects.

Ultrastructural changes during lung carcinogenesis-modulation by curcumin and quercetin

The aim of the present study was to examine the effectiveness of curcumin and quercetin in modulating ultrastructural changes during lung carcinogenesis. A total of 24 male laka mice were divided into the normal control, benzo[a]pyrene (BP)-treated, BP+curcumin-treated, BP+quercetin- treated, and BP+curcumin+quercetin-treated groups (n=6 per group). Lung carcinogenesis was induced by a single intraperitoneal injection of BP [100 mg/kg of body weight (b.wt.)]. Curcumin was supplemented to mice at a dose level of 60 mg/kg of b.wt. in drinking water and quercetin was given at a dose level of 40 mg/kg of b.wt. in drinking water. The ultrastructure of BP-treated mice revealed disruptions in cellular integrity together with nuclear deformation and premature mitochondrial aging. Notably, supplementation with phytochemicals individually resulted in improvement of the ultra-histoarchitecture of BP-treated mice although the improvement was much greater with combined supplementation of phytochemicals. Furthermore, BP treatment revealed alterations in lung histoarchitecture, which, however, were improved appreciably following combined supplementation with curcumin and quercetin. The results of the present study show that, combined supplementation with curcumin and quercetin effectively preserved the histoarchitecture as well as ultra-histoarchitecture during BP-induced lung carcinogenesis in mice.

Benzo(a)pyrene Induced p53 Mediated Male Germ Cell Apoptosis: Synergistic Protective Effects of Curcumin and Resveratrol

Benzo(a)pyrene (B(a)P) is an environmental toxicant that induces male germ cell apoptosis. Curcumin and resveratrol are phytochemicals with cytoprotective and anti-oxidative properties. At the same time resveratrol is also a natural Aryl hydrocarbon Receptor (AhR) antagonist. Our present study in isolated testicular germ cell population from adult male Wistar rats, highlighted the synergistic protective effect of curcumin and resveratrol against B(a)P induced p53 mediated germ cell apoptosis. Curcumin-resveratrol significantly prevented B(a)P induced decrease in sperm cell count and motility, as well as increased serum testosterone level. Curcumin-resveratrol co-treatment actively protected B(a)P induced testicular germ cell apoptosis. Curcumin-resveratrol co-treatment decreased the expression of pro-apoptotic proteins like cleaved caspase 3, 8 and 9, cleaved PARP, Apaf1, FasL, tBid. Curcumin-resveratrol co-treatment decreased Bax/Bcl2 ratio, mitochondria to cytosolic translocation of cytochrome c and activated the survival protein Akt. Curcumin-resveratrol decreased the expression of p53 dependent apoptotic genes like Fas, FasL, Bax, Bcl2, and Apaf1. B(a)P induced testicular reactive oxygen species (ROS) generation and oxidative stress were significantly ameliorated with curcumin and resveratrol. Curcumin-resveratrol co-treatment prevented B(a)P induced nuclear translocation of AhR and CYP1A1 (Cytochrome P4501A1) expression. The combinatorial treatment significantly inhibited B(a)P induced ERK 1/2, p38 MAPK and JNK 1/2 activation. B(a)P treatment increased the expression of p53 and its phosphorylation (p53 ser 15). Curcumin-resveratrol co-treatment significantly decreased p53 level and its phosphorylation (p53 ser 15). The study concludes that curcumin-resveratrol synergistically modulated MAPKs and p53, prevented oxidative stress, regulated the expression of pro and anti-apoptotic proteins as well as the proteins involved in B(a)P metabolism thus protected germ cells from B(a)P induced apoptosis.

Challenges in Analyzing the Biological Effects of Resveratrol

The suggested health effects (e.g., disease prevention) of dietary bioactive compounds such as resveratrol are challenging to prove in comparison to man-made drugs developed for therapeutic purposes. Dietary bioactive compounds have multiple cellular targets and therefore have a variety of biological effects. Extrapolating the biological effects of dietary compounds from in vitro and in vivo animal experiments to humans may lead to over- or under-estimation of the effect and role of these compounds. The present paper will discuss a few of these challenges and suggest directions for future research. Questions we address include: (1) Is the combinatorial effect of resveratrol and other compounds real? (2) What are the real and relevant doses of resveratrol after administration? and (3) Is it possible to estimate the preventive effect of resveratrol by clinical trials using standard experimental designs? The examples concerning resveratrol taken from the scientific literature are mainly from 2010 and later. The challenges pointed out in this review are similar to most naturally occurring bioactive compounds.

Natural compound-derived epigenetic regulators targeting epigenetic readers, writers and erasers

Post-translational modifications can affect gene expression in a long-term manner without changes in the primary nucleotide sequence of the DNA. These epigenetic alterations involve dynamic processes that occur in histones, chromatin-associated proteins and DNA. In response to environmental stimuli, abnormal epigenetic alterations cause disorders in the cell cycle, apoptosis and other cellular processes and thus contribute to the incidence of diverse diseases, including cancers. In this review, we will summarize recent studies focusing on certain epigenetic readers, writers, and erasers associated with cancer development and how newly discovered natural compounds and their derivatives could interact with these targets. These advances provide insights into epigenetic alterations in cancers and the potential utility of these alterations as therapeutic targets for the future development of chemopreventive and chemotherapeutic drugs.

Role of Natural Stilbenes in the Prevention of Cancer

Natural stilbenes are an important group of nonflavonoid phytochemicals of polyphenolic structure characterized by the presence of a 1,2-diphenylethylene nucleus. Stilbenes have an extraordinary potential for the prevention and treatment of different diseases, including cancer, due to their antioxidant, cell death activation, and anti-inflammatory properties which associate with low toxicity under in vivo conditions. This review aims to discuss various approaches related to their mechanisms of action, pharmacological activities in animal models and humans, and potential chemoprevention in clinical studies. The biological activity of natural stilbenes is still incompletely understood. Furthermore, after administration to animals or humans, these molecules are rapidly metabolized. Thus pharmacokinetics and/or activities of the natural structures and their metabolites may be very different. Novel drug formulations have been postulated in order to improve stability and bioavailability, to minimize side effects, and to facilitate interaction with their domains in target proteins. These pharmacological improvements should lead stilbenes to become effective candidates as anticancer drugs.

Polyphenols as Modulator of Oxidative Stress in Cancer Disease: New Therapeutic Strategies

Cancer onset and progression have been linked to oxidative stress by increasing DNA mutations or inducing DNA damage, genome instability, and cell proliferation and therefore antioxidant agents could interfere with carcinogenesis. It is well known that conventional radio-/chemotherapies influence tumour outcome through ROS modulation. Since these antitumour treatments have important side effects, the challenge is to develop new anticancer therapeutic strategies more effective and less toxic for patients. To this purpose, many natural polyphenols have emerged as very promising anticancer bioactive compounds. Beside their well-known antioxidant activities, several polyphenols target epigenetic processes involved in cancer development through the modulation of oxidative stress. An alternative strategy to the cytotoxic treatment is an approach leading to cytostasis through the induction of therapy-induced senescence. Many anticancer polyphenols cause cellular growth arrest through the induction of a ROS-dependent premature senescence and are considered promising antitumour therapeutic tools. Furthermore, one of the most innovative and interesting topics is the evaluation of efficacy of prooxidant therapies on cancer stem cells (CSCs). Several ROS inducers-polyphenols can impact CSCs metabolisms and self-renewal related pathways. Natural polyphenol roles, mainly in chemoprevention and cancer therapies, are described and discussed in the light of the current literature data.

Curcumin inhibits B[a]PDE-induced procarcinogenic signals in lung cancer cells, and curbs B[a]P-induced mutagenesis and lung carcinogenesis

Benzo[a]pyrene is a procarcinogen present in environment and cigarette smoke, which could be bio-transformed in vivo to B[a]PDE, a potent carcinogen known to form DNA adducts and induce mutations. We observed that curcumin, a known chemopreventive, could significantly inhibit the survival of lung cancer cells exposed to B[a]PDE. It also downregulates B[a]PDE-induced nuclear translocation of NF-κB as assessed by Electrophoretic Mobility Shift Assay (EMSA) and NF-κB-dependent reporter gene assay. Ames assay demonstrated its ability to revert the mutagenic property of benzo[a]pyrene. These observations prompted us to evaluate the efficacy of curcumin in preventing B[a]P-induced lung carcinogenesis in vivo and to explore the molecular mechanism associated with it. The average number of tumor nodules present in the lungs of the Swiss albino mice, which received benzo[a]pyrene, was significantly high compared to that received curcumin as 2% diet along with B[a]P. Curcumin treatment significantly reverted histopathological deviations in the lung tissues due to benzo[a]pyrene ingestion. Moreover, curcumin diet reduced benzo[a]pyrene-induced activation of NF-κB and MAPK signaling and Cox-2 transcription in lung tissues of mice. Taken together, this study illustrates multifaceted efficacy of curcumin in preventing lung cancer.

Resveratrol Enhances Etoposide-Induced Cytotoxicity through Down-Regulating ERK1/2 and AKT-Mediated X-ray Repair Cross-Complement Group 1 (XRCC1) Protein Expression in Human Non-Small-Cell Lung Cancer Cells

Etoposide (VP-16), a topoisomerase II inhibitor, is an effective anti-cancer drug used for the treatment of non-small-cell lung cancer (NSCLC). Resveratrol is a naturally occurring polyphenolic compound that has been proved to have anti-cancer activity. XRCC1 is an important scaffold protein involved in base excision repair that is regulated by ERK1/2 and AKT signals and plays an important role in the development of lung cancer. However, the role of ERK1/2 and AKT-mediated XRCC1 expression in etoposide treatment alone or combined with resveratrol-induced cytotoxicity in NSCLC cells has not been identified. In this study, etoposide treatment increased XRCC1 mRNA and protein expression through AKT and ERK1/2 activation in two NSCLC cells, H1703 and H1975. Knockdown of XRCC1 in NSCLC cells by transfection of XRCC1 siRNA or inactivation of ERK1/2 and AKT resulted in enhancing cytotoxicity and cell growth inhibition induced by etoposide. Resveratrol inhibited the expression of XRCC1 and enhanced the etoposide-induced cell death and anti-proliferation effect in NSCLC cells. Furthermore, transfection with constitutive active MKK1 or AKT vectors could rescue the XRCC1 protein level and also the cell survival suppressed by co-treatment with etoposide and resveratrol. These findings suggested that down-regulation of XRCC1 expression by resveratrol can enhance the chemosensitivity of etoposide in NSCLC cells.

The pharmacology of resveratrol in animals and humans

In addition to thousands of research papers related to resveratrol (RSV), approximately 300 review articles have been published. Earlier research tended to focus on pharmacological activities of RSV related to cardiovascular systems, inflammation, and carcinogenesis/cancer development. More recently, the horizon has been broadened by exploring the potential effect of RSV on the aging process, diabetes, neurological dysfunction, etc. Herein, we primarily focus on the in vivo pharmacological effects of RSV reported over the past 5 years (2009-2014). In addition, recent clinical intervention studies performed with resveratrol are summarized. Some discrepancies exist between in vivo studies with animals and clinical studies, or between clinical studies, which are likely due to disparate doses of RSV, experimental settings, and subject variation. Nevertheless, many positive indications have been reported with mammals, so it is reasonable to advocate for the conduct of more definitive clinical studies. Since the safety profile is pristine, an added advantage is the use of RSV as a dietary supplement. This article is part of a Special Issue entitled: Resveratrol: Challenges in translating pre-clinical findings to improved patient outcomes.

Curcumin and resveratrol in combination modulate drug-metabolizing enzymes as well as antioxidant indices during lung carcinogenesis in mice

This study investigated combined chemopreventive potential of curcumin and resveratrol during benzo(a)pyrene (BP)-induced lung carcinogenesis in mice. The mice were segregated into five groups that included normal control, BP-treated, BP + curcumin-treated, BP + resveratrol-treated, and BP + curcumin + resveratrol-treated groups. A statistically significant increase in the levels of lipid peroxidation (LPO) was observed in the lungs of mice after 22 weeks of single dose of benzo(a)pyrene. Further, BP treatment also resulted in a significant increase in the enzyme activities of aryl hydrocarbon hydroxylase as well as drug-metabolizing enzymes, namely cytocrome P450 and cytochrome b5. On the other hand, reduced glutathione (GSH) levels, the activities of superoxide dismutase (SOD), glutathione reductase (GR), and glutathione- S-transferase (GST) were found to be significantly decreased following BP treatment. Supplementation with curcumin and resveratrol to BP-treated mice significantly decreased the LPO levels, GSH levels, and enzyme activities of drug-metabolizing enzymes. Further, treatment of curcumin and resveratrol to BP-treated mice significantly elevated the activities of SOD, GR, and GST. Histoarchitectural studies showed well-differentiated signs of lung carcinogenesis following BP administration to mice. However, combined treatment with curcumin and resveratrol resulted in a noticeable improvement in the lung histoarchitecture. This study, therefore, concludes that curcumin and resveratrol when supplemented in combination regulate drug-metabolizing enzymes as well as antioxidant enzymes during lung carcinogenesis in mice.

Resveratrol and cancer: Challenges for clinical translation

Significant work has been done towards identifying the health-beneficial effects of the grape antioxidant resveratrol in a variety of bioassay- and disease- models, with much research being focused on its possible application to cancer management. Despite the large number of preclinical studies dealing with different aspects of the biological effects of resveratrol, its translation to clinics is far from reality due to a variety of challenges. In this review, we discuss the issues and questions associated with resveratrol becoming an effective in vivo anticancer drug, from basic metabolic issues to the problems faced by incomplete understanding of the mechanism(s) of action in the body. We also explore efforts taken by researchers, both public and private, to contend with some of these issues. By examining the published data and previous clinical trials, we have attempted to identify the problems and issues that hinder the clinical translation of resveratrol for cancer management. This article is part of a Special Issue entitled: Resveratrol: Challenges in translating pre-clinical findings to improved patient outcomes.

Curcumin as a protector for normal cells during bortezomib therapy

This study evaluated the protective potential of curcumin on the possible side effects of bortezomib (Bt) therapy on normal cells in mice. The mice were segregated into three groups ( n = 10) that included normal control, Bt-treated, and Bt + curcumin-treated groups. The Bt treatment resulted in significant decrease in the enzyme activity of erythrocyte δ-aminolevulinic acid dehydratase (ALAD). Also a significant decrease in the hemoglobin (Hb) was also noticed. On the other hand, curcumin co-treatment improvised enzyme activity of erythrocyte ALAD as well as Hb values. The study, therefore, concludes that curcumin co-treatment with Bt has a potential to take care of possible side effects of Bt therapy on normal cells.

Caspase-9 as a therapeutic target for treating cancer

INTRODUCTION

Caspase-9 is the apoptotic initiator protease of the intrinsic or mitochondrial apoptotic pathway, which is activated at multi-protein activation platforms. Its activation is believed to involve homo-dimerization of the monomeric zymogens. It binds to the apoptosome to retain substantial catalytic activity. Variety of apoptotic stimuli can regulate caspase-9. However, the mechanism of action of various regulators of caspase-9 has not been summarized and compared yet. In this article, we elucidate the regulators of caspase-9 including microRNAs, natural compounds that are related to caspase-9 and ongoing clinical trials with caspase-9 to better understand the caspase-9 in suppressing cancer.

AREAS COVERED

In this study, the basic mechanism of apoptosis pathways, regulators of caspase-9 and the development of drugs to regulate caspase-9 are reviewed. Also, ongoing clinical trials for caspase-9 are discussed.

EXPERT OPINION

Apoptosis has crucial role in cancer, brain disease, aging and heart disease to name a few. Since caspase-9 is an initiator caspase of apoptosis, it is an important therapeutic target of various diseases related to apoptosis. Therefore, a deep understanding on the roles as well as regulators of caspase-9 is required to find more effective ways to conquer apoptosis-related diseases especially cancer.

Targeting the histone orthography of cancer: drugs for writers, erasers and readers

Gene expression is dynamically controlled by epigenetics through post-translational modifications of histones, chromatin-associated proteins and DNA itself. All these elements are required for the maintenance of chromatin structure and cell identity in the context of a normal cellular phenotype. Disruption of epigenetic regulation is a common event in human cancer. Here, we review the key protein families that control epigenetic signalling through writing, erasing or reading specific post-translational modifications. By exploiting the leading role of epigenetics in tumour development and the reversibility of epigenetic modifications, promising novel epigenetic-based therapies are being developed. In this article, we highlight the emerging low MW inhibitors targeting each class of chromatin-associated protein, their current use in preclinical and clinical trials and the likelihood of their being approved in the near future.