Capsaicin-induced apoptosis in SK-Hep-1 hepatocarcinoma cells involves Bcl-2 downregulation and caspase-3 activation

Capsaicin Exerts Antitumor Activity in Mesothelioma Cells

BACKGROUND/OBJECTIVES

Mesothelioma is an aggressive cancer with limited treatment options. Mesothelioma therapy often involves a multimodal approach including surgery, radiotherapy and chemotherapy. However, the prognosis for patients remains poor. Difficult diagnosis, late symptoms when the tumor is in an advanced stage and the onset of chemotherapy resistance make mesothelioma difficult to treat. For this reason, it is essential to discover new pharmacological approaches. Capsaicin (CAPS) is the active compound of chili peppers. Based on CAPS's anticancer properties on various tumor lines and its chemo-sensitizing action on resistant cells, in this study, we evaluated the effects of CAPS on mesothelioma cells to assess its potential use in mesothelioma therapy.

METHODS

To evaluate antiproliferative effects of CAPS, we performed MTS assays on various mesothelioma cells, representative of all major mesothelioma subtypes. Transwell migration and wound-healing assays were used to examine the effect of CAPS on mesothelioma cell migration. We also determined the effects of CAPS on oncogenic signaling pathways by assessing the levels of AKT and MAPK activation.

RESULTS

In this study, we show that CAPS significantly reduces proliferation of both parental and cisplatin-resistant mesothelioma cells. CAPS promotes S-phase cell cycle arrest and inhibits lateral motility and migration of mesothelioma cells. Accordingly, CAPS suppresses AKT and ERK1/2 activation in MSTO-211H and NCI-H2052 cells. Our results support an antitumor effect of CAPS on cisplatin-resistant mesothelioma cells, suggesting that it may reduce resistance to cisplatin.

CONCLUSIONS

Our results could pave the way for further studies to evaluate the use of CAPS for mesothelioma treatment.

Appraisal of postbiotics in cancer therapy

Cancer remains a multifactorial disease with an increased mortality rate around the world for the past several decades. Despite advancements in treatment strategies, lower survival rates, drug-associated side effects, and drug resistance create a need for novel anticancer agents. Ample evidence shows that imbalances in the gut microbiota are associated with the formation of cancer and its progression. Altering the gut microbiota via probiotics and their metabolites has gained attention among the research community as an alternative therapy to treat cancer. Probiotics exhibit health benefits as well as modulate the immunological and cellular responses in the host. Apart from probiotics, their secreted products like bacteriocins, exopolysaccharides, short-chain fatty acids, conjugated linoleic acid, peptidoglycan, and other metabolites are found to possess anticancer activity. The beneficiary role of these postbiotic compounds is widely studied for characterizing their mechanism and mode of action that reduces cancer growth. The present review mainly focuses on the postbiotic components that are employed against cancer with their reported mechanism of action. It also describes recent research works carried out so far with specific strain and anticancer activity of derived compounds both in vitro and in vivo, validating that the probiotic approach would pave an alternative way to reduce the burden of cancer.

Capsaicin: a spicy way in liver disease

The incidence of liver disease continues to rise, encompassing a spectrum from simple steatosis or non-alcoholic fatty liver disease (NAFLD) to non-alcoholic steatohepatitis (NASH), cirrhosis and liver cancer. Dietary habits in individuals with liver disease may significantly impact the treatment and prevention of these conditions. This article examines the role of chili peppers, a common dietary component, in this context, focusing on capsaicin, the active ingredient in chili peppers. Capsaicin is an agonist of the transient receptor potential vanilloid subfamily 1 (TRPV1) and has been shown to exert protective effects on liver diseases, including liver injury, NAFLD, liver fibrosis and liver cancer. These protective effects are attributed to capsaicin's anti-oxidant, anti-inflammatory, anti-steatosis and anti-fibrosis effects. This article reviewed the different molecular mechanisms of the protective effect of capsaicin on liver diseases.

Bioeconomy and ethnopharmacology - Translational perspective and sustainability of the bioresources of northeast region of India

ETHNOPHARMACOLOGICAL RELEVANCE

The ecological environment of Northeast region of India (NER), with its high humidity, has resulted in greater speciation and genetic diversity of plant, animal, and microbial species. This region is not only rich in ethnic and cultural diversity, but it is also a major biodiversity hotspot. The sustainable use of these bioresources can contribute to the region's bioeconomic development.

AIM OF THE STUDY

The review aimed to deliver various perspectives on the development of bioeconomy from NER bioresources under the tenets of sustainable utilization and socioeconomic expansion.

MATERIALS AND METHODS

Relevant information related to prospects of the approaches and techniques pertaining to the sustainable use of ethnomedicine resources for the growth of the bioeconomy were retrieved from PubMed, ScienceDirect, Google Scholar, Scopus, and Springer from 1984 to 2023. All the appropriate abstracts, full-text articles and various book chapters on bioeconomy and ethnopharmacology were conferred.

RESULT

As the population grows, so does the demand for basic necessities such as food, health, and energy resources, where insufficient resource utilization and unsustainable pattern of material consumption cause impediments to economic development. On the other hand, the bioeconomy concept leads to "the production of renewable biological resources and the conversion of these resources and waste streams into value-added products.

CONCLUSIONS

In this context, major emphasis should be placed on strengthening the economy's backbone in order to ensure sustainable use of these resources and livelihood security; in other words, it can boost the bio-economy by empowering the local people in general.

Capsaicin: Emerging Pharmacological and Therapeutic Insights

Capsaicin, the most prominent pungent compound of chilli peppers, has been used in traditional medicine systems for centuries; it already has a number of established clinical and industrial applications. Capsaicin is known to act through the TRPV1 receptor, which exists in various tissues; capsaicin is hepatically metabolised, having a half-life correlated with the method of application. Research on various applications of capsaicin in different formulations is still ongoing. Thus, local capsaicin applications have a pronounced anti-inflammatory effect, while systemic applications have a multitude of different effects because their increased lipophilic character ensures their augmented bioavailability. Furthermore, various teams have documented capsaicin's anti-cancer effects, proven both in vivo and in vitro designs. A notable constraint in the therapeutic effects of capsaicin is its increased toxicity, especially in sensitive tissues. Regarding the traditional applications of capsaicin, apart from all the effects recorded as medicinal effects, the application of capsaicin in acupuncture points has been demonstrated to be effective and the combination of acupuncture and capsaicin warrants further research. Finally, capsaicin has demonstrated antimicrobial effects, which can supplement its anti-inflammatory and anti-carcinogenic actions.

Exopolysaccharides of lactic acid bacteria: Structure, biological activity, structure-activity relationship, and application in the food industry: A review

Over the past few decades, researchers have discovered that probiotics play an important role in our daily lives. With the further deepening of research, more and more evidence show that bacterial metabolites have an important role in food and human health, which opens up a new direction for the research of lactic acid bacteria (LAB) in the food and pharmaceutical industry. Many LAB have been widely studied because of the ability of exopolysaccharides (EPS). Lactic acid bacteria exopolysaccharides (LAB EPS) not only have great potential in the treatment of human diseases but also can become natural ingredients in the food industry to provide special qualitative structure and flavor. This paper has organized and summarized the biosynthesis, strain selection, production process parameters, structure, and biological activity of LAB EPS, filling in the monotony and incompleteness of previous articles' descriptions of LAB EPS. Therefore, this paper focuses on the general biosynthetic pathway, structural characterization, structure-activity relationship, biological activity of LAB EPS, and their application in the food industry, which will help to deepen people's understanding of LAB EPS and develop new active drugs from LAB EPS. Although the research results are relatively affluent, the low yield, complex structure, and few clinical trials of EPS are still the reasons that hinder its development. Therefore, future knowledge expansion should focus on the regulation of structure, physicochemical properties, function, higher production of EPS, and clinical trial applications, which can further increase the commercial significance and value of EPS. Furthermore, better understanding the structure-function relationship of EPS in food remains a challenge to date.

Phytochemicals as Potential Lead Molecules against Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most prevalent form of liver cancer, accounting for 85-90% of liver cancer cases and is a leading cause of cancer-related mortality worldwide. The major risk factors for HCC include hepatitis C and B viral infections, along with chronic liver diseases, such as cirrhosis, fibrosis, and non-alcoholic steatohepatitis associated with metabolic syndrome. Despite the advancements in modern medicine, there is a continuous rise in the annual global incidence rate of HCC, and it is estimated to reach >1 million cases by 2025. Emerging research in phytomedicine and chemotherapy has established the anti-cancer potential of phytochemicals, owing to their diverse biological activities. In this review, we report the major phytochemicals that have been explored in combating hepatocellular carcinoma and possess great potential to be used as an alternative or in conjunction with the existing HCC treatment modalities. An overview of the pre-clinical observations, mechanism of action and molecular targets of some of these phytochemicals is also incorporated.

Curcumin and capsaicin regulate apoptosis and alleviate intestinal inflammation induced by Clostridioides difficile in vitro

Background

The dramatic upsurge of Clostridioides difficile infection (CDI) by hypervirulent isolates along with the paucity of effective conventional treatment call for the development of new alternative medicines against CDI. The inhibitory effects of curcumin (CCM) and capsaicin (CAP) were investigated on the activity of toxigenic cell-free supernatants (Tox-S) of C. difficile RT 001, RT 126 and RT 084, and culture-filtrate of C. difficile ATCC 700057.

Methods

Cell viability of HT-29 cells exposed to varying concentrations of CCM, CAP, C. difficile Tox-S and culture-filtrate was assessed by MTT assay. Anti-inflammatory and anti-apoptotic effects of CCM and CAP were examined by treatment of HT-29 cells with C. difficile Tox-S and culture-filtrate. Expression of BCL-2, SMAD3, NF-κB, TGF-β and TNF-α genes in stimulated HT-29 cells was measured using RT-qPCR.

Results

C. difficile Tox-S significantly (P < 0.05) reduced the cell viability of HT-29 cells in comparison with untreated cells. Both CAP and CCM significantly (P < 0.05) downregulated the gene expression level of BCL-2, SMAD3, NF-κB and TNF-α in Tox-S treated HT-29 cells. Moreover, the gene expression of TGF-β decreased in Tox-S stimulated HT-29 cells by both CAP and CCM, although these reductions were not significantly different (P > 0.05).

Conclusion

The results of the present study highlighted that CCM and CAP can modulate the inflammatory response and apoptotic effects induced by Tox-S from different clinical C. difficile strains in vitro. Further studies are required to accurately explore the anti-toxin activity of natural components, and their probable adverse risks in clinical practice.

Capsaicin suppresses hepatocarcinogenesis by inhibiting the stemness of hepatic progenitor cells via SIRT1/SOX2 signaling pathway

BACKGROUND & AIMS

Capsaicin, a functional component of chili pepper, possesses anti-inflammatory, analgesic, and anti-cancer properties. This study aimed to determine the property of capsaicin against hepatocarcinogenesis in vivo and investigate the role of the SIRT1/SOX2 pathway in the mode of action of capsaicin in hepatic progenitor cells (HPCs), which is related to hepatocarcinogenesis.

MATERIALS & METHODS

We prepared a diethylnitrosamine-induced liver cancer model in rats to examine hepatocarcinogenesis, and delivered liposomal capsaicin through the subcutaneous transposition of the spleen to the liver. Liver sections from rats and hepatocarcinoma patients were stained for the markers of HPCs or SIRT1/SOX2 signaling. SIRT1/SOX2 signalling expression was measured using immunoprecipitation and western blot.

RESULTS

We found that capsaicin significantly inhibited hepatocarcinogenesis. Notably, capsaicin inhibited HPCs activation in vivo but did not induce apoptosis in the normal hepatic progenitor cell line in rats in vitro. This suggests that capsaicin suppresses hepatocarcinogenesis by inhibiting the stemness of HPCs. Moreover, capsaicin can induce this inhibition by reducing the stability of SOX2. SIRT1 is overexpressed in liver cancer and acts as a tumor promoter via SOX2 deacetylation. Using immunoprecipitation, we identified direct binding between SIRT1 and SOX2. The capsaicin treatment resulted in SIRT1 downregulation which reduced deacetylation, and increased nuclear export as well as subsequent ubiquitous degradation of SOX2.

CONCLUSIONS

Altogether, we report that capsaicin suppresses hepatocarcinogenesis by inhibiting the stemness of HPCs via SIRT1/SOX2 signaling. It may serve as a promising therapeutic candidate for liver cancer.

Network Pharmacology Integrated with Transcriptomics Deciphered the Potential Mechanism of Codonopsis pilosula against Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fourth main reason of cancer-related death. Codonopsis pilosula is a commonly used traditional Chinese medicine (TCM) for patients with HCC. However, its potential mechanism for treatment of HCC remains unclear. Here, we used transcriptomics and network pharmacology to explore the potential molecular mechanisms of Codonopsis pilosula. In our study, twelve differentially expressed genes (DEGs) (5 upregulated and 7 downregulated) of Codonopsis pilosula treating HepG2 cells (a kind of HCC cell) were identified. Among the 12 DEGs, HMOX1 may play an essential role. Codonopsis pilosula mainly affects the mineral absorption pathway in HCC. We acquired 2957, 1877, and 255 targets from TCMID, SymMap, and TCMSP, respectively. Codonopsis pilosula could upregulate HMOX1 via luteolin, capsaicin, and sulforaphane. Our study provided new understanding of the potential pharmacological mechanisms of Codonopsis pilosula in treating HCC and pointed out a direction for further experimental research.

Emerging role of natural products in cancer immunotherapy

Cancer immunotherapy has become a new generation of anti-tumor treatment, but its indications still focus on several types of tumors that are sensitive to the immune system. Therefore, effective strategies that can expand its indications and enhance its efficiency become the key element for the further development of cancer immunotherapy. Natural products are reported to have this effect on cancer immunotherapy, including cancer vaccines, immune-check points inhibitors, and adoptive immune-cells therapy. And the mechanism of that is mainly attributed to the remodeling of the tumor-immunosuppressive microenvironment, which is the key factor that assists tumor to avoid the recognition and attack from immune system and cancer immunotherapy. Therefore, this review summarizes and concludes the natural products that reportedly improve cancer immunotherapy and investigates the mechanism. And we found that saponins, polysaccharides, and flavonoids are mainly three categories of natural products, which reflected significant effects combined with cancer immunotherapy through reversing the tumor-immunosuppressive microenvironment. Besides, this review also collected the studies about nano-technology used to improve the disadvantages of natural products. All of these studies showed the great potential of natural products in cancer immunotherapy.

Capsaicin inhibits cell proliferation by enhancing oxidative stress and apoptosis through SIRT1/NOX4 signaling pathways in HepG2 and HL-7702 cells

Capsaicin could suppress the proliferation of cancer cells and inhibit many biochemical pathways associated with tumorigenesis and metastasis. This study investigates the effects of capsaicin in both hepatocellular carcinoma (HepG2) and normal hepatocytes (HL-7702) via the SIRT1/NOX4 signaling pathway. After determination of cytotoxic concentrations of capsaicin on HL-7702 and HepG2 cells, we measured total oxidant status (TOS), reduced glutathione (GSH), 8-hydroxydeoxyguanosine (8-OHdG), cytochrome c (CYC), caspase3 (CASP3), Bcl-2, Bax, sirtuin1 (SIRT1), and NADPH oxidases4 (NOX4) levels. Besides this, we analyzed the messenger RNA and protein levels of SIRT1 and NOX4. We found that capsaicin increased TOS, 8-OHdG, CASP3, CYC, Bax, and NOX4 levels, and decreased Bcl-2, GSH, and SIRT1 in a concentration-dependent manner in HepG2 cells. However, especially low capsaicin concentration (128.75 µM) enhanced GSH and SIRT levels and reduced TOS, CASP3, CYC, 8-OHdG, and NOX4 levels in HL-7702 cells (p < 0.05). Interestingly, 128.75 and 172.8 µM capsaicin treatment increased SIRT1 expression levels in HL-7702 cells, resulting in an increase in GSH levels and a decrease in TOS, CYC, CAPS3, and 8-OHdG levels through NOX4 inhibition. Furthermore, we demonstrated a significant decrease in SIRT1 protein levels and an increase in NOX4 protein levels and caspase-3/-7 activities in both HL-7702 and HepG2 cells treated with 261.5 µM capsaicin. Additionally, morphological changes in HL-7702 and HepG2 cells treated with capsaicin correlated with the enhancement in oxidative burden, DNA damage, and apoptosis. Our results show that capsaicin effectively might cause higher oxidative, apoptotic, and DNA damage in HepG2 cells than in HL-7702 cells through the SIRT1/NOX4 signaling pathway.

Anti-Hepatocellular Carcinoma Biomolecules: Molecular Targets Insights

This report explores the available curative molecules directed against hepatocellular carcinoma (HCC). Limited efficiency as well as other drawbacks of existing molecules led to the search for promising potential alternatives. Understanding of the cell signaling mechanisms propelling carcinogenesis and driven by cell proliferation, invasion, and angiogenesis can offer valuable information for the investigation of efficient treatment strategies. The complexity of the mechanisms behind carcinogenesis inspires researchers to explore the ability of various biomolecules to target specific pathways. Natural components occurring mainly in food and medicinal plants, are considered an essential resource for discovering new and promising therapeutic molecules. Novel biomolecules normally have an advantage in terms of biosafety. They are also widely diverse and often possess potent antioxidant, anti-inflammatory, and anti-cancer properties. Based on quantitative structure-activity relationship studies, biomolecules can be used as templates for chemical modifications that improve efficiency, safety, and bioavailability. In this review, we focus on anti-HCC biomolecules that have their molecular targets partially or completely characterized as well as having anti-cancer molecular mechanisms that are fairly described.

Enzymes, In Vivo Biocatalysis, and Metabolic Engineering for Enabling a Circular Economy and Sustainability

Since the industrial revolution, the rapid growth and development of global industries have depended largely upon the utilization of coal-derived chemicals, and more recently, the utilization of petroleum-based chemicals. These developments have followed a linear economy model (produce, consume, and dispose). As the world is facing a serious threat from the climate change crisis, a more sustainable solution for manufacturing, i.e., circular economy in which waste from the same or different industries can be used as feedstocks or resources for production offers an attractive industrial/business model. In nature, biological systems, i.e., microorganisms routinely use their enzymes and metabolic pathways to convert organic and inorganic wastes to synthesize biochemicals and energy required for their growth. Therefore, an understanding of how selected enzymes convert biobased feedstocks into special (bio)chemicals serves as an important basis from which to build on for applications in biocatalysis, metabolic engineering, and synthetic biology to enable biobased processes that are greener and cleaner for the environment. This review article highlights the current state of knowledge regarding the enzymatic reactions used in converting biobased wastes (lignocellulosic biomass, sugar, phenolic acid, triglyceride, fatty acid, and glycerol) and greenhouse gases (CO₂ and CH₄) into value-added products and discusses the current progress made in their metabolic engineering. The commercial aspects and life cycle assessment of products from enzymatic and metabolic engineering are also discussed. Continued development in the field of metabolic engineering would offer diversified solutions which are sustainable and renewable for manufacturing valuable chemicals.

Anticarcinogenic Effects of Capsaicin-Loaded Nanoparticles on In vitro Hepatocellular Carcinoma

Background::

Hepatocellular Carcinoma (HCC) is the fifth most frequent cancer worldwide with a low overall survival due to high metastasis and recurrence rates. The aim of this study is to assess and compare the possible anti-neoplastic effect of capsaicin and nanoformulated capsaicin on in vitro HCC human cell line HepG2. The source of the cell line, including when and from where it was obtained. Whether the cell line has recently been authenticated and by what method. Whether the cell line has recently been tested for mycoplasma contamination.

Materials and Methods::

Capsaicin-loaded Trimethyl Chitosan Nanoparticles (CL TMCS NPs) were synthesized by ionotropic gelation of cationic TMCS with capsaicin. The synthesized nanoparticles were characterized through TEM, and zeta analyzer. Human hepatocarcinoma HepG2 cell lines were cultured and treated with 50, 75 & 100 μM of Capsaicin (CAP), plain TMCS NPs and CL-NPs as well as ethanol (control) for 24h and 48h. The induced effects were investigated by flow cytometry, immunocytochemistry assay for Bcl-2, Bax, and caspase proteins and evaluating gene expression levels of Bcl-2, Bax, and MDR-1 mRNA by real-time PCR.

Results::

Our results demonstrated that capsaicin- loaded NPs had the potential to significantly increase capsaicin bioactivity compared with the plain capsaicin formulation either in inducing apoptosis through altering expression of apoptotic regulators or modifying MDR-1 expression.

Conclusions::

TMCs nanoparticles investigated in this study may be a good drug delivery vehicle for capsaicin. Application of capsaicin-loaded NPs in HCC management as an adjunct therapeutic approach may be a novel strategy to improve the treatment efficacy and resistance of the conventionally used chemotherapy.

Dihydrocapsaicin Inhibits Cell Proliferation and Metastasis in Melanoma via Down-regulating β-Catenin Pathway

Dihydrocapsaicin (DHC) is one of the main components of capsaicinoids in Capsicum. It has been reported that DHC exerts anti-cancer effects on diverse malignant tumors, such as colorectal cancer, breast cancer, and glioma. However, studies focused on the effect of DHC upon melanoma have rarely been done. In the present study, melanoma A375 and MV3 cell lines were treated with DHC and the cell proliferation, migration, and invasion were significantly suppressed. Furthermore, DHC effectively inhibited xenograft tumor growth and pulmonary metastasis of melanoma cells in NOD/SCID mice model. It was identified that β-catenin, which plays significant roles in cell proliferation and epithelial-mesenchymal transition, was down-regulated after DHC treatment. In addition, cyclin D1, c-Myc, MMP2, and MMP7, which are critical in diverse cellular process regulation as downstream proteins of β-catenin, were all decreased. Mechanistically, DHC accelerates ubiquitination of β-catenin and up-regulates the beta-transducin repeat containing E3 ubiquitin protein ligase (BTRC) in melanoma cells. The DHC induced suppression of cell proliferation, migration, and invasion were partly rescued by exogenous β-catenin overexpression, both in vitro and in vivo. Taken together, DHC may serve as a candidate natural compound for human melanoma treatment through β-catenin pathway.

Ras Signaling in Breast Cancer

Ras proteins mediate extracellular and cytoplasmic signaling networks via receptor tyrosine kinase. The Ras pathway induces activation of signaling molecules involved in cell proliferation and growth, cell survival and apoptosis, metabolism, and motility. Although Ras mutations in breast cancer are not frequently reported, hyperactivation of Ras signaling plays an important role in breast cancer growth and progression. Oncogenic Ras activation occurs via loss of Ras GTPase-activating proteins, overexpression of growth factor receptor, and stimulation by various cytokines. Effective control of oncogenic Ras is one of the therapeutic strategies in breast cancer. The mechanisms of intracellular localization, activation, and signaling pathway of Ras in cancer have been used to develop therapeutic candidates. Recent studies have reported an effective therapy for breast cancer by inhibition of enzymes involved in the posttranslational modification of Ras, such as farnesyltransferase and geranylgeranyltransferase 1, and anti-cancer therapies targeting the epidermal growth factor receptor (EGFR). Emerging targets involved in EGF-mediated Ras activity in breast cancer have shed new insight into Ras activation in breast cancer progression. These alternative mechanisms for Ras signaling pathway may suggest novel therapeutic approaches for targeting Ras in breast cancer. In spite of the difficulties in targeting Ras protein, important discoveries highlight the direct inhibition of Ras activity. Further studies may elucidate the effects of targeting Ras protein and the clinical relevance thereof.

Chemopreventive and anticancer activities of indomethacin and vitamin D combination on colorectal cancer induced by 1,2-dimethylhydrazine in rats

Several studies have revealed that the combination of indomethacin, a nonsteroidal anti-inflammatory drug (NSAID), and vitamin D reduces the risk of common types of cancers. Nonetheless, research on the deal concentrations used to test the impact of vitamin D on colon cancer is deficient. Along these lines, the aim of the present study was to evaluate the possible role of indomethacin and vitamin D as a preventative as well as a therapeutic operator for colon cancer growth induced by dimethylhydrazine (DMH) in male Albino rats. Fifty male albino rats were utilized in this examination; five groups were assigned from the animals (10 animals each): i) control group considered healthy animals; ii) carcinogen group that received DMH only; iii) prophylactic group; iv) vitamin D and indomethacin-treated group; and v) 5-flurouracil (5-FU) group. Western blot technique was used to determine the expression of carcinoembryonic antigen (CEA) and platelet-derived growth factor (PDGF). Overexpression of CEA and PDGF was noted in the carcinogenic group, while expression of CEA and PDGF in the prophylactic, vitamin D and indomethacin and 5-FU groups were markedly reduced. There was a likewise decline in tissue caspase-3 activity and antioxidant parameters in the carcinogenic group, while, there was an increase in these markers in the 5-FU group as well as the prophylactic and vitamin D and indomethacin groups. The combination of vitamin D and indomethacin markedly reduced the incidence and severity of colon cancer. The molecular, biochemical and histopathological analysis related with the oral administration of vitamin D and indomethacin display its capacity to limit the frequency of colorectal cancer.

Exopolysaccharides from probiotic bacteria and their health potential

Exopolysaccharides (EPS) are extracellular macromolecules excreted as tightly bound capsule or loosely attached slime layer in microorganisms. They play most prominent role against desiccation, phagocytosis, cell recognition, phage attack, antibiotics or toxic compounds and osmotic stress. In the last few decades, natural polymers have gained much attention among scientific communities owing to their therapeutic potential. In particular the EPS retrieved from probiotic bacteria with varied carbohydrate compositions possess a plenty of beneficial properties. Different probiotic microbes have unique behavior in expressing their capability to display significant health promoting characteristics in the form of polysaccharides. In this new era of alternative medicines, these polysaccharides are considered as substitutes for synthetic drugs. The EPS finds applications in various fields like textiles, cosmetics, bioremediation, food and therapeutics. The present review is focused on sources, chemical composition, biosynthetic pathways of EPS and their biological potential. More attention has been given to the scientific investigations on antimicrobial, antitumor, anti-biofilm, antiviral, anti-inflammatory and immunomodulatory activities.

The Antiproliferative and Apoptotic Effects of Capsaicin on an Oral Squamous Cancer Cell Line of Asian Origin, ORL-48

Background and Objectives: The antitumor activities of capsaicin on various types of cancer cell lines have been reported but the effect of capsaicin on oral cancer, which is prevalent among Asians, are very limited. Thus, this study aimed to investigate the effects of capsaicin on ORL-48, an oral cancer cell line of Asian origin. Materials and Methods: Morphological changes of the ORL-48 cells treated with capsaicin were analyzed using fluorescence microscopy. The apoptotic-inducing activity of capsaicin was further confirmed by Annexin V-Fluorescein isothiocyanate / Propidium iodide (V-FITC/PI) staining using flow cytometry. In order to establish the pathway of apoptosis triggered by the compound on ORL-48 cells, caspase activity was determined and the mitochondrial pathway was verified by mitochondrial membrane potential (MMP) assay. Cell cycle analysis was also performed to identify the cell cycle phase of ORL-48 cells being inhibited by the capsaicin compound. Results: Fluorescence microscopy exhibited the presence of apoptotic features in capsaicin-treated ORL-48 cells. Apoptosis of capsaicin-treated ORL-48 cells revealed disruption of the mitochondrial-membrane potential, activation of caspase-3, -7 and -9 through an intrinsic apoptotic pathway and subsequently, apoptotic DNA fragmentation. The cell cycle arrest occurred in the G1-phase, confirming antiproliferative effect of capsaicin in a time-dependent manner. Conclusion: This study demonstrated that capsaicin is cytotoxic against ORL-48 cells and induces apoptosis in ORL-48 cells possibly through mitochondria mediated intrinsic pathway resulting in cell cycle arrest.

Capsaicin: Effects on the Pathogenesis of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most frequent cancers, and to date, there have been very few drugs available that can improve survival, the most well-known being sorafenib. The pathogenesis of HCC is complex, involving multiple processes including abnormal cell and tissue regeneration, angiogenesis, genomic instability, cellular proliferation, and signaling pathway alterations. Capsaicin is a substance that holds increasingly high interest and is studied as a therapeutic option in a wide array of diseases. Several studies have investigated capsaicin roles in various stages of HCC oncogenesis. This paper aims to thoroughly detail the available information on the individual effects of capsaicin on the cellular mechanisms and pathways involved in HCC development, as well as investigate their possible cooperation and interferences. The synergistic antitumor effects of capsaicin and sorafenib are also addressed.

Capsaicin in Hot Chili Peppers: In Vitro Evaluation of Its Antiradical, Antiproliferative and Apoptotic Activities

Capsaicin is a spicy capsaicinoid, produced as secondary metabolite by Capsicum fruits. This alkaloid has been used for years in folk medicine for its analgesic and antinflammatory properties although most data is referred to the raw fruit. In this study, the antiradical activity of the pure capsaicin has been studied using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays as well as its antiproliferative activity, using MTT assay, against two human tumour cell lines, the colorectal Caco-2 and the oesophageal OE19 cells. Furthermore, the antiproliferative activity observed on tumoral cells was compared with that of the human normal-like fibroblast cell line TelCOFS02MA. In addition, the apoptotic activity was evaluated using TUNEL assay. A higher radical scavenging activity was observed against ABTS radical cation than DPPH. Capsaicin showed also a higher cytotoxicity against cancer cells than normal-like cells with Selectivity index values greater than 2 at 72 h. Capsaicin induced apoptosis especially in OE19 cell line.

Capsaicin enhances erlotinib-induced cytotoxicity via AKT inactivation and excision repair cross-complementary 1 (ERCC1) down-regulation in human lung cancer cells

Capsaicin, a natural active ingredient of green and red peppers, has been demonstrated to exhibit anti-cancer properties in several malignant cell lines. Excision repair cross-complementary 1 (ERCC1) has a leading role in the nucleotide excision repair (NER) process because of its involvement in the excision of DNA adducts. Erlotinib (Tarceva^R) is a selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that has demonstrated clinical activity in non-small cell lung cancer (NSCLC) cells. However, whether capsaicin and erlotinib could induce synergistic cytotoxicity in NSCLC cells through modulating ERCC1 expression is unknown. In this study, capsaicin decreased the ERCC1 expression in an AKT inactivation dependent manner in two human lung adenocarcinoma cells, namely, A549 and H1975. Enhancement of AKT activity by transfection with constitutive active AKT vectors increased the ERCC1 protein level as well as the cell survival by capsaicin. Moreover, capsaicin synergistically enhanced the cytotoxicity and cell growth inhibition of erlotinib in NSCLC cells, which were associated with the down-regulation of ERCC1 expression and inactivation of AKT in A549 and H1975 cells. Together, these results may provide a rationale to combine capsaicin with erlotinib for lung cancer treatment.

In vitro evaluation of the effects of capsaicin on normal and cancerous cells of human cartilage

Chondrosarcoma is a common form of bone cancer which effects the fibrous connective tissue around a joint. It most commonly develops in legs, arms, shoulder blades, rib cage, and pelvis. Capsaicin is an active bitter compound found in red pepper, the fruit of the species Capsicum annuum, and it has been shown to have a lethal effect on different types of cancer. However, to date, investigation of its effect on human chondrosarcoma cells has remained limited. In the study presented here, we determined IC50 values of capsaicin for chondrosarcoma and chondrocyte cells in both fetal bovine serum (FBS)-containing and FBS-deprived media, and no statistically significant difference was found between the cell types. Besides, when the cells were cultured with capsaicin at their determined IC50 value for 24 h and their caspase-3 gene expression levels were detected by real-time polymerase chain reaction (RTPCR) and western blotting, it was demonstrated that the caspase-3 protein and mRNA levels were not altered in any cells upon capsaicin exposure, suggesting a caspase-independent pathway for cell death. Migration and invasion abilities of the cancerous cells, on the other hand, were observed to decrease dramatically when the cells were exposed to capsaicin (P < 0.05).

Capsaicin-induced TRIB3 upregulation promotes apoptosis in cancer cells

Background

Capsaicin (8-methyl-N-vanillyl-6-nonenamide) is one of the main pungent components of chili peppers and has been shown to exert various effects on numerous physiological processes. Recent studies have focused on the chemopreventive effects of capsaicin, which can combat growth in various human cancer cell systems. The tribbles-related protein 3 (TRIB3) is evolutionarily conserved from Drosophila to humans. In the latter, TRIB3 is a key determinant in numerous cellular processes, including apoptosis.

Purpose

The aim of this study was to examine the importance of TRIB3 in the antitumor efficacy of capsaicin in human cancer cells, and further assess potential mechanism(s) underlying the capsaicin-induced upregulation of TRIB3.

Methods

Human cancer cell lines were treated with capsaicin, then evaluated for levels of TRIB3 and molecules related to apoptosis or signaling pathways. The impact of TRIB3 on capsaicin-induced apoptosis was investigated using si-RNA or overexpression of TRIB3.

Results

It is the first time to show that TRIB3 is targeted by capsaicin to promote apoptosis. Capsaicin promotes apoptotic cell death by upregulating TRIB3 expression in cancer cells. Overexpression of TRIB3 enhances capsaicin-induced apoptosis, and TRIB3 knockdown experiments demonstrate that the effect of capsaicin in apoptotic cell death is correlated with the induction of TRIB3 in cancer cells. Finally, enhancements in gene expression and protein stability are involved in the capsaicin-induced upregulation of TRIB3.

Conclusion

Our results show that the capsaicin-induced upregulation of TRIB3 triggers apoptosis and thereby contributes to the suppression of cell growth in cancer cell lines.

Capsaicin enhances the antitumor activity of sorafenib in hepatocellular carcinoma cells and mouse xenograft tumors through increased ERK signaling

Sorafenib, a small inhibitor of tyrosine protein kinases, is currently the standard chemotherapy drug for the treatment of advanced hepatocellular carcinoma (HCC). Although sorafenib improves the survival of HCC patients, its efficacy is not optimal and requires further improvement. Capsaicin, the major active component of chili peppers from the genus Capsicum, is not only the agonist of TRPV1 channel, but also displays antitumor activity and enhances the sensitivity of cancer cells to cytotoxic drugs. In this study, we investigated the antitumor effects of combined sorafenib and capsaicin on HCC cells in vitro and xenograft tumors. Treatment with capsaicin alone dose-dependently inhibited the proliferation of the HCC cell lines PLC/PRF/7, HuH7 and HepG2 with IC₅₀ values of 137, 108 and 140.7 μmol/L, respectively. No obvious expression of TRPV1 channel was detected in the 3 HCC cell lines and TRPV1 channel blockers did not alleviate the cytotoxicity of capsaicin. By contrast, combining capsaicin and sorafenib significantly enhanced the suppression on cell proliferation, achieving a high-level synergistic effect (inhibition rates over 50%) and promoting HCC cell apoptosis. In nude mice with PLC/PRF/5 xenografts, combined administration of capsaicin and sorafenib significantly enhanced the suppression on tumor growth without apparent gross toxicity compared to either agent alone. Mechanistically, capsaicin (10-200 μmol/L) dose-dependently increased the levels of phosphorylated ERK (p-ERK) in PLC/PRF/5 cells, thus leading to enhanced sorafenib sensitivity and a synergistic suppression on the tumor cells. Taken together, our results suggest that capsaicin-increased phosphorylation of ERK contributes to the enhanced antitumor activity of sorafenib, and capsaicin may be useful in improving the efficacy of sorafenib for the treatment of HCC.

Capsaicin exerts synergistic antitumor effect with sorafenib in hepatocellular carcinoma cells through AMPK activation

In this study, we investigated the antitumoral effects of combined treatment using sorafenib and capsaicin in hepatocellular carcinoma (HCC) cells. Here we showed that the combination of the two drugs had a much stronger inhibitory effect on both HepG2 and Huh-7 human HCC cells growth than either drug alone. The isobolograms demonstrated that the combinations investigated in this study produced a synergistic interaction. In the combination treatment using capsaicin and sorafenib, increased apoptosis, followed by the activation of caspase-9 and PARP, was observed. In addition, the present study demonstrated that sorafenib treatment induces activation of Akt, probably as a mechanism of resistance, whereas capsaicin inhibits Akt providing a possible pathway whereby capsaicin sensitizes to sorafenib in HCC cells. Moreover, capsaicin singly and the combination of capsaicin and sorafenib induce AMPK activation and Acetyl CoA carboxylase phosphorylation in HCC cells. Knocking down of AMPK by selective siRNA abrogates capsaicin-induced Akt inhibition, suggesting the involvement of AMPK in the antiproliferative effect. In vivo experiments further showed that that the anti-tumor effect of sorafenib was enhanced by its combination with 2.5 mg/Kg of capsaicin. Overall, these results show that combined treatment with capsaicin and sorafenib might improve sorafenib sensitivity and therefore it represents a promising and attractive strategy for the treatment of HCC.

Capsaicin inhibits proliferation and induces apoptosis in osteosarcoma cell lines via the mitogen‑activated protein kinase pathway

Capsaicin, a pungent molecular compound present in many hot peppers, exerts anticancer activities against various human cancer cell lines by inducing apoptosis. However, the effects of capsaicin on human osteosarcoma (OS) as well as the related mechanisms remain to be fully elucidated. In the present study, the anticancer effects of capsaicin on 3 human OS cell lines (MG63, 143B and HOS) were investigated. Various concentrations of capsaicin (50-300 µM) effectively decreased cell viability in all 3 OS cell lines in a dose-dependent manner. Notably, capsaicin-induced apoptosis was observed when OS cells were treated with relatively high concentrations of capsaicin (starting at 250 µM). In addition, the mitochondrial apoptotic pathway was involved in the capsaicin-induced apoptosis in the OS cells. Meanwhile, our results also indicated that at relatively low concentrations (e.g., 100 µM), capsaicin could inhibit the proliferation, decrease the colony forming ability and induce G0/G1 phase cell cycle arrest of OS cells in a dose-dependent manner. Moreover, our results revealed that the anticancer effects induced by capsaicin on OS cell lines involved multiple MAPK signaling pathways as indicated by inactivation of the ERK1/2 and p38 pathways and activation of the JNK pathway. Furthermore, the results of animal experiments showed that capsaicin inhibited tumor growth in a xenograft model of human OS. In conclusion, these results indicate that capsaicin may exert therapeutic benefits as an adjunct to current cancer therapies but not as an independent anticancer agent.

Hepatoprotective Mongolian prescription II enhances the antitumor effects of chemotherapeutics in hepatocellular carcinoma xenografts

Hepatoprotective Mongolian prescription II (MPII), a mixture of 18 different medicinal herbs, significantly inhibited the growth of human liver cancer cell lines Huh-7 and HepG2 in vitro with different concentrations; MPII (6mg/mL) inhibited cell proliferation by 80.48%. MPII induced apoptosis in both cell lines, which was observed by light microscopy and flow cytometry. MPII-induced apoptosis and G0/G1 cell cycle arrest were quantified by Annexin V-FITC/PI staining and flow cytometry. At the molecular level, MPII induced caspase-3, caspase-8, caspase-9, and cytochrome c gene expression. In vivo, MPII dramatically inhibited human liver tumor growth in a xenograft model in Kunming mice with no apparent cytotoxicity to the hosts. Apoptotic genes (Bcl-2 and Bax) are up-regulated, suggesting that the ratio of Bcl-2/Bax was statistically significant, indicating that the drugs had affected the expression of apoptosis genes, especially on induce apoptosis gene Bax. We also observed an attenuated effect when MPII was used in combination with chemotherapy drug 5-fluorouracil (5-FU). The mice treated with 5-FU alone did not show a concentration-dependent effect, but 5-FU in combination with MPII displayed concentration-dependent effects on liver cancer cells. Our study suggests that MPII works by inducing apoptosis and cell cycle arrest, and has the potential to be a powerful anticancer agent.

An updated review on molecular mechanisms underlying the anticancer effects of capsaicin

The quest for developing anticancer principles from natural sources has a long historical track record and remarkable success stories. The pungent principle of hot chili pepper, capsaicin, has been a subject of research for anticancer drug discovery for more than three decades. However, the majority of research has revealed that capsaicin interferes with various hallmarks of cancer, such as increased cell proliferation, evasion from apoptosis, inflammation, tumor angiogenesis and metastasis, and tumor immune escape. Moreover, the compound has been reported to inhibit carcinogen activation and chemically induced experimental tumor growth. Capsaicin has also been reported to inhibit the activation of various kinases and transcription that are involved in tumor promotion and progression. The compound activated mitochondria-dependent and death receptor-mediated tumor cell apoptosis. Considering the growing interest in capsaicin, this review provides an update on the molecular targets of capsaicin in modulating oncogenic signaling.

In vivo and in vitro evaluation for nutraceutical purposes of capsaicin, capsanthin, lutein and four pepper varieties

The purpose of this study is to determine the nutraceutic potential of different Capsicum sp, capsaicin, capsanthin and lutein and provide data in order to clarify the conflicting results obtained for capsaicin by different authors. To achieve these objectives, in vivo (geno/antigenotoxicity and lifespan assays in the animal model Drosophila) and in vitro (cytotoxicity and DNA-fragmentation assays in HL60 promyelocytic cell line) assays were carried out. Results showed that i) none of the tested substances were genotoxic except green hot pepper and capsaicin at the highest tested concentration (5 mg/mL and 11.5 μM respectively), ii) all tested substances except green hot pepper are antimutagenic against H₂O₂-induced damage, iii) only red sweet pepper significantly extend the lifespan and healthspan of D. melanogaster at 1.25 and 2.5 mg/mL, iv) all pepper varieties induce dose-depended cytotoxic effect in HL60 cells with different IC₅₀, and v) all pepper varieties and capsaicin exerted proapoptotic effect on HL60 cells.

IN CONCLUSION

(i) sweet peppers could be suggested as nutraceutical food, (ii) hot peppers should be moderately consumed, and (iii) supplementary studies are necessary to clarify the synergic effect of the carotenoids and capsaicinoids in the hot pepper food matrix.

Capsaicin mediates caspases activation and induces apoptosis through P38 and JNK MAPK pathways in human renal carcinoma

BACKGROUND

Renal cell carcinoma (RCC) is one of the tumors most refractory to chemotherapy to date. Therefore, novel therapeutic agents are urgently needed for this disease. Capsaicin (CPS), a natural active ingredient of green and red peppers, and a ligand of transient receptor potential vanilloid type 1 (TRPV1), has been showed potential in suppression of tumorigenesis of several cancers. Nonetheless, the anti-cancer activity of CPS has never been studied in human RCC.

METHODS

CCK8 analysis, LDH release activity and ROS generation analysis, flow cytometry analysis, and nuclear staining test were performed to test the influence of CPS in cultured cells in vitro, meanwhile western blot was done to uncover the precise molecular mechanisms. 786-O renal cancer xenografts were builded to investigate the antitumor activity of CPS in vivo.

RESULTS

We found treatment of CPS reduced proliferation of renal carcinoma cells, which could be attenuated by TRPV1 representative antagonist capsazepine (CPZ). CPS induced obvious apoptosis in renal carcinoma cells. These events were associated with substantial up-regulation of pro-apoptotic genes including c-myc, FADD, Bax and cleaved-caspase-3, -8, and -9, while down-regulation of anti-apoptotic gene Bcl2. Besides, CPS-treatment activated P38 and JNK MAPK pathways, yet P38 and JNK inhibitors afforded protection against CPS-induced apoptosis by abolishing activation of caspase-3, -8, and -9. Furthermore, CPS significantly slowed the growth of 786-O renal cancer xenografts in vivo.

CONCLUSIONS

Such results reveal that CPS is an efficient and potential drug for management of human RCC.

Capsaicin triggers immunogenic PEL cell death, stimulates DCs and reverts PEL-induced immune suppression

Capsaicin, the pungent alkaloid of red pepper has been extensively studied for its many properties, especially the anti-inflammatory and anti-oxidant ones. It binds to vanilloid receptor 1, although it has been reported to be able to mediate some effects independently of its receptor. Another important property of Capsaicin is the anticancer activity against highly malignant tumors, alone or in combination with other chemotherapeutic agents. In this study, we found that Capsaicin induced an apoptotic cell death in PEL cells correlated with the inhibition of STAT3. STAT3 pathway, constitutively activated in PEL cells, is essential for their survival. By STAT3 de-phosphorylation, Capsaicin reduced the Mcl-1 expression level and this could represent one of the underlying mechanisms leading to the Capsaicin-mediated cell death and autophagy induction. Next, by pharmacological or genetic inhibition, we found that autophagy played a pro-survival role, suggesting that its inhibition could be exploited to increase the Capsaicin cytotoxic effect against PEL cells. Finally, we show that Capsaicin induced DAMP exposure, as for an immunogenic cell death, directly promoted DC activation and, more importantly, that it counteracted the immune-suppression, in terms of DC differentiation, mediated by the PEL released factors.

Emerging Role of Sensory Perception in Aging and Metabolism

Sensory perception comprises gustatory (taste) and olfactory (smell) modalities as well as somatosensory (pain, heat, and tactile mechanosensory) inputs, which are detected by a multitude of sensory receptors. These sensory receptors are contained in specialized ciliated neurons where they detect changes in environmental conditions and participate in behavioral decisions ranging from food choice to avoiding harmful conditions, thus insuring basic survival in metazoans. Recent genetic studies, however, indicate that sensory perception plays additional physiological functions, notably influencing energy homeostatic processes and longevity through neuronal circuits originating from sensory tissues. Here we review how these findings are redefining metabolic signaling and establish a prominent role of sensory neuroendocrine processes in controlling health span and lifespan, with a goal of translating this knowledge towards managing age-associated diseases.

Inhibition of β-catenin signaling suppresses pancreatic tumor growth by disrupting nuclear β-catenin/TCF-1 complex: critical role of STAT-3

Aberrant activation of β-catenin/TCF signaling is related to the invasiveness of pancreatic cancer. In the present study, we evaluated the effect of capsaicin on β-catenin/TCF signaling. In a concentration and time-dependent study, we observed that capsaicin treatment inhibits the activation of dishevelled (Dsh) protein DvI-1 in L3.6PL, PanC-1 and MiaPaCa-2 pancreatic cancer cells. Capsaicin treatment induced GSK-3β by inhibiting its phosphorylation and further activated APC and Axin multicomplex, leading to the proteasomal degradation of β-catenin. Expression of TCF-1 and β-catenin-responsive proteins, c-Myc and cyclin D1 also decreased in response to capsaicin treatment. Pre-treatment of cells with MG-132 blocked capsaicin-mediated proteasomal degradation of β-catenin. To establish the involvement of β-catenin in capsaicin-induced apoptosis, cells were treated with LiCl or SB415286, inhibitors of GSK-3β. Our results reveal that capsaicin treatment suppressed LiCl or SB415286-mediated activation of β-catenin signaling. Our results further showed that capsaicin blocked nuclear translocation of β-catenin, TCF-1 and p-STAT-3 (Tyr705). The immunoprecipitation results indicated that capsaicin treatment reduced the interaction of β-catenin and TCF-1 in the nucleus. Moreover, capsaicin treatment significantly decreased the phosphorylation of STAT-3 at Tyr705. Interestingly, STAT-3 over expression or STAT-3 activation by IL-6, significantly increased the levels of β-catenin and attenuated the effects of capsaicin in inhibiting β-catenin signaling. Finally, capsaicin mediated inhibition of orthotopic tumor growth was associated with inhibition of β-catenin/TCF-1 signaling. Taken together, our results suggest that capsaicin-induced apoptosis in pancreatic cancer cells was associated with inhibition of β-catenin signaling due to the dissociation of β-catenin/TCF-1 complex and the process was orchestrated by STAT-3.

Natural Products for Chemoprevention of Breast Cancer

Breast cancer is the primary cause of cancer death in women. Although current therapies have shown some promise against breast cancer, there is still no effective cure for the majority of patients in the advanced stages of breast cancer. Development of effective agents to slow, reduce, or reverse the incidence of breast cancer in high-risk women is necessary. Chemoprevention of breast cancer by natural products is advantageous, as these compounds have few side effects and low toxicity compared to synthetic compounds. In the present review, we summarize natural products which exert chemopreventive activities against breast cancer, such as curcumin, sauchinone, lycopene, denbinobin, genipin, capsaicin, and ursolic acid. This review examines the current knowledge about natural compounds and their mechanisms that underlie breast cancer chemopreventive activity both in vitro and in vivo. The present review may provide information on the use of these compounds for the prevention of breast cancer.

The effect of ripening, heat processing and frozen storage on the in vitro bioaccessibility of capsaicin and dihydrocapsaicin from Jalapeño peppers in absence and presence of two dietary fat types

To date, there is no information in the literature regarding the bioaccessibility of capsaicinoids from natural sources. The effect of ripening and heat-processing on the in vitro bioaccessibility of capsaicin and dihydrocapsaicin was studied in the absence and presence of two dietary fat types. The capsaicinoid bioaccessibility was also studied during the frozen storage of peppers for 6 months. Fresh green peppers showed the highest capsaicinoid bioaccessibility, as compared with that of other experimental groups. The bioaccessibility of capsaicinoids from green peppers decreased as the intensity of heat treatment increased. The dietary fat increased the bioaccessibility of capsaicin and dihydrocapsaicin in digestions with red peppers, especially that of dihydrocapsaicin. The bioaccessibility of capsaicinoids was altered by frozen storage. The Caco-2 cells incorporated capsaicin and dihydrocapsaicin (8.4% and 10.9%, respectively) but they were probably metabolized by cells.

Inhibitory effects of capsaicin on hepatic stellate cells and liver fibrosis

Hepatic stellate cells (HSCs) play an important role in the process of liver fibrosis. In this study, we investigated the inhibitory effects of capsaicin on HSCs and liver fibrosis. Cultured HSCs were incubated with various concentrations of capsaicin. Cell proliferation was examined using a cell counting kit. Production of hydrogen peroxide was determined using a 2′,7′-dichlorofluorescin diacetate (DCFH-DA) assay. The mRNA and protein expression of target genes was analyzed by reverse transcription PCR and Western blot analysis, respectively. Cell apoptosis was evaluated by annexin V-FITC and propidium iodide (PI) costaining followed by flow cytometric analysis. A CCl4 rat liver fibrosis model was used to assess in vivo effects of capsaicin by histological examination and measurement of liver fibrosis markers, including hydroxyproline content, serum type III collagen, and hyaluronic acid (HA) levels. Our results show that capsaicin dose-dependently inhibited cell proliferation, suppressed cell activation, and decreased hydrogen peroxide production in cultured HSCs. Capsaicin reduced the mRNA levels of tissue inhibitors of metalloproteinase 1 (TIMP-1) and transforming growth factor-β1 (TGF-β1) in HSCs. Moreover, capsaicin-induced cell apoptosis was associated with increased expression of Bax, cytochrome c (cyt c), and caspase-3, but reduced levels of Bcl-2. The animal studies further revealed that capsaicin efficiently reduced the extent of liver fibrosis, inhibited HSC proliferation, and promoted cell apoptosis. Our findings suggest that capsaicin might inhibit fibrogenesis by inhibiting the activities of HSCs.

Capsaicin-induced activation of p53-SMAR1 auto-regulatory loop down-regulates VEGF in non-small cell lung cancer to restrain angiogenesis

Lung cancer is the leading cause of cancer-related deaths worldwide. Despite decades of research, the treatment options for lung cancer patients remain inadequate, either to offer a cure or even a substantial survival advantage owing to its intrinsic resistance to chemotherapy. Our results propose the effectiveness of capsaicin in down-regulating VEGF expression in non-small cell lung carcinoma (NSCLC) cells in hypoxic environment. Capsaicin-treatment re-activated p53-SMAR1 positive feed-back loop in these cells to persuade p53-mediated HIF-1α degradation and SMAR1-induced repression of Cox-2 expression that restrained HIF-1α nuclear localization. Such signal-modulations consequently down regulated VEGF expression to thwart endothelial cell migration and network formation, pre-requisites of angiogenesis in tumor micro-environment. The above results advocate the candidature of capsaicin in exclusively targeting angiogenesis by down-regulating VEGF in tumor cells to achieve more efficient and cogent therapy of resistant NSCLC.

Bladder cancer and urothelial impairment: the role of TRPV1 as potential drug target

Urothelium, in addition to its primary function of barrier, is now understood to act as a complex system of cell communication that exhibits specialized sensory properties in the regulation of physiological or pathological stimuli. Furthermore, it has been hypothesized that bladder inflammation and neoplastic cell growth, the two most representative pathological conditions of the lower urinary tract, may arise from a primary defective urothelial lining. Transient receptor potential vanilloid channel 1 (TRPV1), a receptor widely distributed in lower urinary tract structures and involved in the physiological micturition reflex, was described to have a pathophysiological role in inflammatory conditions and in the genesis and development of urothelial cancer. In our opinion new compounds, such as curcumin, the major component of turmeric Curcuma longa, reported to potentiate the effects of the chemotherapeutic agents used in the management of recurrent urothelial cancer in vitro and also identified as one of several compounds to own the vanillyl structure required to work like a TRPV1 agonist, could be thought as complementary in the clinical management of both the recurrences and the inflammatory effects caused by the endoscopic resection or intravesical chemotherapy administration or could be combined with adjuvant agents to potentiate their antitumoral effect.

Capsaicin treatment attenuates cholangiocarcinoma carcinogenesis

Capsaicin, the most abundant pungent molecule produced by pepper plants, represents an important ingredient in spicy foods consumed throughout the world. Studies have shown that capsaicin can relieve inflammation and has anti-proliferative effects on various human malignancies. Cholangiocarcinoma (CC) is a cancer disease with rising incidence. The prognosis remains dismal with little advance in treatment. The aim of the present study is to explore the anti-tumor activity of capsaicin in cultured human CC cell lines. Capsaicin effectively impaired cell proliferation, migration, invasion, epithelial to mesenchymal transition and growth of softagar colonies. Further, we show that capsaicin treatment of CC cells regulates the Hedgehog signaling pathway.

CONCLUSION

Our results provide a basis for capsaicin to improve the prognosis of CCs in vivo and present new insights into the effectiveness and mode of action of capsaicin.

Restoration of p53/miR-34a regulatory axis decreases survival advantage and ensures Bax-dependent apoptosis of non-small cell lung carcinoma cells

Tumor-suppressive miR-34a, a direct target of p53, has been shown to target several molecules of cell survival pathways. Here, we show that capsaicin-induced oxidative DNA damage culminates in p53 activation to up-regulate expression of miR-34a in non-small cell lung carcinoma (NSCLC) cells. Functional analyses further indicate that restoration of miR-34a inhibits B cell lymphoma-2 (Bcl-2) protein expression to withdraw the survival advantage of these resistant NSCLC cells. In such a proapoptotic cellular milieu, where drug resistance proteins are also down-regulated, p53-transactivated Bcl-2 associated X protein (Bax) induces apoptosis via the mitochondrial death cascade. Our results suggest that p53/miR-34a regulatory axis might be critical in sensitizing drug-resistant NSCLC cells.

Capsaicin induces apoptosis in human osteosarcoma cells through AMPK-dependent and AMPK-independent signaling pathways

Recent studies have focused on the anti-tumor activity of capsaicin. However, the potential effects of capsaicin in osteosarcoma cells and the underlying mechanisms are not fully understood. In the current study, we observed that capsaicin-induced growth inhibition and apoptosis in cultured osteosarcoma cells (U2OS and MG63), which were associated with a significant AMP-activated protein kinase (AMPK) activation. AMPK inhibition by compound C or RNA interference suppressed capsaicin-induced cytotoxicity, while AMPK activators (AICAR and A769662) promoted osteosarcoma cell death. For the mechanism study, we found that AMPK activation was required for capsaicin-induced mTORC1 (mTOR complex 1) inhibition, B cell lymphoma 2 (Bcl-2) downregulation and Bax upregulation in MG63 cells. Capsaicin administration induced p53 activation, mitochondrial translocation and Bcl-2 killer association, such effects were dependent on AMPK activation. Interestingly, we observed a significant pro-apoptotic c-Jun NH2-terminal kinases activation by capsaicin in MG63 cells, which appeared to be AMPK independent. In conclusion, capsaicin possessed strong efficacy against human osteosarcoma cells. Molecular studies revealed that capsaicin activated AMPK-dependent and AMPK-independent signalings to mediate cell apoptosis. The results of this study should have significant translational relevance in managing this deadly malignancy.

Capsaicin induces cell cycle arrest and apoptosis in human KB cancer cells

BACKGROUND

Capsaicin, a pungent phytochemical in a variety of red peppers of the genus Capsicum, has shown an anti-proliferative effect on various human cancer cell lines. In contrast, capsaicin has also been considered to promote the growth of cancer cells. Thus, the effects of capsaicin on various cell types need to be explored. The anti-proliferative effects of capsaicin on human KB cancer cells are still unknown. Therefore, we examined the viability, cell cycle progression, and factors associated with apoptosis in KB cells treated with capsaicin.

METHODS

The cell proliferation/viability and cytotoxicity of KB cells exposed to capsaicin were determined by a sulforhodamine B colorimetric assay and trypan blue exclusion. Apoptosis was detected by Hoechst staining and confirmed by western blot analysis of poly-(ADP-ribose) polymerase cleavage. Cell cycle distribution and changes of the mitochondrial membrane potential were analyzed by flow cytometry. Furthermore, the expression of caspase 3, 8 and 9 was evaluated by immunoblotting.

RESULTS

We found that treatment of KB cells with capsaicin significantly reduced cell proliferation/viability and induced cell death in a dose-dependent manner compared with that in the untreated control. Cell cycle analysis indicated that exposure of KB cells to capsaicin resulted in cell cycle arrest at G2/M phase. Capsaicin-induced growth inhibition of KB cells appeared to be associated with induction of apoptosis. Moreover, capsaicin induced disruption of the mitochondrial membrane potential as well as activation of caspase 9, 3 and poly-(ADP-ribose) polymerase in KB cells.

CONCLUSIONS

Our data demonstrate that capsaicin modulates cell cycle progression and induces apoptosis in human KB cancer cells through mitochondrial membrane permeabilization and caspase activation. These observations suggest an anti-cancer activity of capsaicin.