Capsaicin enhances anti-proliferation efficacy of pirarubicin via activating TRPV1 and inhibiting PCNA nuclear translocation in 5637 cells

Capsaicin enhances cisplatin-induced anti-metastasis of nasopharyngeal carcinoma by inhibiting EMT and ERK signaling via serpin family B member 2

Cisplatin (DDP)-based combined chemotherapy or concurrent chemoradiotherapy is the mainstay treatment for advanced-stage nasopharyngeal carcinoma (NPC), but needs improvement due to its severe side effects. Capsaicin (CAP) can enhance the anti-tumor activity of cytotoxic drugs. The aim of this study was to investigate the anti-metastasis activity of CAP in combination with DDP in NPC. Herein, CAP and DDP showed synergistic cytotoxic effects on NPC cells. CAP alone and DDP alone inhibited NPC migration and invasion in vitro and in vivo, and the combination of CAP and DDP had the greatest effect. Moreover, CAP upregulated the mRNA and protein expressions of serpin family B member 2 (SERPINB2). Further results showed that both SERPINB2 mRNA and protein expressions were downregulated in NPC cell lines and tissues and SERPINB2 overexpression inhibited NPC migration and invasion in vitro and in vivo, while silencing SERPINB2 acted oppositely. In addition, SERPINB2 was abnormally expressed in head and neck squamous cell carcinoma and other multiple cancers, and downregulation of SERPINB2 predicted poor prognosis in head and neck squamous cell carcinoma according to the Cancer Genome Atlas database. We further found that SERPINB2 overexpression inhibited epithelial-mesenchymal transition (EMT) and the phosphorylated extracellular signal-regulated kinase (p-ERK), and the inhibitory effect was enhanced by CAP and DDP. Altogether, our results suggest that the combined inhibition of CAP and DDP on NPC metastasis may be related to the inhibition of epithelial-mesenchymal transition and ERK signals mediated by SERPINB2, and CAP may help to improve the efficacy of DDP in the treatment of NPC and develop new therapeutic approaches.

Transient receptor potential vanilloid-1 (TRPV1) channels act as suppressors of the growth of glioma

The aim of this study was to investigate the expression and function of the transient receptor potential vanilloid 1 (TRPV1) in glioma. We found that the expression of TRPV1 mRNA and protein were upregulated in glioma compared with normal brain by qPCR and western blot analysis. In order to investigate the function of TRPV1 in glioma, short hairpin RNA (shRNA) and the inhibitor of TRPV1 were used. In vitro, the activation of TRPV1 induced cell apoptosis with decreased migration capability and inhibited proliferation, which was abolished upon TRPV1 pharmacological inhibition and silencing. Mechanistically, TRPV1 modulated glioma proliferation through the protein kinase B (Akt) signaling pathway. More importantly, in immunodeficient (NOD-SCID) mouse xenograft models, tumor size was significantly increased when TRPV1 expression was disrupted by a shRNA knockdown approach in vivo. Altogether, our findings indicate that TRPV1 negatively controls glioma cell proliferation in an Akt-dependent manner, which suggests that targeting TRPV1 may be a potential therapeutic strategy for glioma.

Transient Receptor Potential Channels in Sensory Mechanisms of the Lower Urinary Tract

BACKGROUND

Urine storage and excretion require a network of interactions in the urinary tract and the central nervous system, which is mediated by a reservoir of water in the bladder and the outlet to the bladder neck, urethra, and external urethral sphincter. Through communicating and coordinating each other, micturition system eventually showed a switch-like activity pattern.

SUMMARY

At cervicothoracic and lumbosacral spine, the spinal reflex pathway of the lower urinary tract (LUT) received mechanosensory input from the urothelium to regulate the bladder contraction activity, thereby controlled urination voluntarily. Impairment of above-mentioned any level could result in lower urinary tract dysfunction, placed a huge burden on patients and society. Specific expression of purinergic receptors and transient receptor potential (TRP) channels are thought to play an important role in urinary excretion in the LUT.

KEY MESSAGES

This article reviewed the knowledge about the voiding reflex and described the role and function of TRP channels during voiding.

Capsaicin: A chili pepper bioactive phytocompound with a potential role in suppressing cancer development and progression

Cancer profoundly influences morbidity and fatality rates worldwide. Patients often have dismal prognoses despite recent improvements in cancer therapy regimens. However, potent biomolecules derived from natural sources, including medicinal and dietary plants, contain biological and pharmacological properties to prevent and treat various human malignancies. Capsaicin is a bioactive phytocompound present in red hot chili peppers. Capsaicin has demonstrated many biological effects, including antioxidant, anti-inflammatory, antimicrobial, and anticarcinogenic capabilities. This review highlights the cellular and molecular pathways through which capsaicin exhibits antineoplastic activities. Our work also depicts the synergistic anticancer properties of capsaicin in conjunction with other natural bioactive components and approved anticancer drugs. Capsaicin inhibits proliferation in various cancerous cells, and its antineoplastic actions in numerous in vitro and in vivo carcinoma models impact oncogenesis, tumor-promoting and suppressor genes, and associated signaling pathways. Capsaicin alone or combined with other phytocompounds or approved antineoplastic drugs triggers cell cycle progression arrest, generating reactive oxygen species and disrupting mitochondrial membrane integrity, ultimately stimulating caspases and promoting death. Furthermore, capsaicin alone or in combination can promote apoptosis in carcinoma cells by enhancing the p53 and c-Myc gene expressions. In conclusion, capsaicin alone or in combination can have enormous potential for cancer prevention and intervention, but further high-quality studies are needed to firmly establish the clinical efficacy of this phytocompound.

Chili pepper extracts, capsaicin, and dihydrocapsaicin as potential anticancer agents targeting topoisomerases

DNA topoisomerases regulate conformational changes in DNA topology during normal cell growth, such as replication, transcription, recombination, and repair, and may be targeted for anticancer drugs. A DNA topology assay was used to investigate DNA-damaging/protective activities of extracts from Habanero Red (HR), Habanero Maya Red (HMR), Trinidad Moruga Scorpion (TMS), Jalapeno (J), Serrano pepper (SP), Habanero Red Savina (HRS), Bhut Jolokia (BJ), and Jamaica Rosso (JR) peppers, demonstrating their inhibitory effect on the relaxation of pBR by Topo I. DNA topoisomerase II (Topo II) is proven therapeutic target of anticancer drugs. Complete inhibition of Topo II was observed for samples TMS, HR, and HMR. Extracts J and SP had the lowest capsaicin and dihydrocapsaicin content compared to other peppers. HR, HMR, TMS, J, S, HRS, BJ, JR extracts showed the anticancer effect, examined by MTS and xCell assay on the in vitro culture of human colon carcinoma cell line HCT116.

Nonivamide inhibits proliferation of human corneal epithelial cells by inducing cell cycle arrest and oxidative stress

Nonivamide, an agonist of transient receptor potential vanilloid type 1 (TRPV1), is widely used as a riot control agent, police incapacitant spray and pesticide. Although generally considered non-fatal, eye discomfort and even ocular injuries caused by such products are common. Little research has been conducted on the effects of nonivamide on corneal epithelial cells. Cell viability, impedance, flow cytometry, western blotting, and real-time fluorescence analyses were performed to investigate the effects of nonivamide on human corneal epithelial cells (HCE-T cells). We found that nonivamide impaired proliferation at subtoxic doses (100 μM and 200 μM) in HCE-T cells. Next, we described the mechanisms of action of nonivamide. Nonivamide caused cell cycle arrest by increasing p21 and decreasing cyclin D1. TRPV1 was activated by nonivamide, leading to an influx of Ca2+. Enhanced Ca2+ influx partially contributed to oxidative stress. Mitochondrial membrane potential (MMP) also decreased. All combined stress resulted in the inhibition of cell proliferation in HCE-T cells. In summary, nonivamide inhibited the proliferation of HCE-T cells at sub-toxic doses by inducing cell cycle arrest and oxidative stress. Our data demonstrate the corneal toxicity of nonivamide and explain the mechanisms underlying nonivamide-induced corneal injury.

Capsaicinoids and Their Effects on Cancer: The "Double-Edged Sword" Postulate from the Molecular Scale

Capsaicinoids are a unique chemical species resulting from a particular biosynthesis pathway of hot chilies (Capsicum spp.) that gives rise to 22 analogous compounds, all of which are TRPV1 agonists and, therefore, responsible for the pungency of Capsicum fruits. In addition to their human consumption, numerous ethnopharmacological uses of chili have emerged throughout history. Today, more than 25 years of basic research accredit a multifaceted bioactivity mainly to capsaicin, highlighting its antitumor properties mediated by cytotoxicity and immunological adjuvancy against at least 74 varieties of cancer, while non-cancer cells tend to have greater tolerance. However, despite the progress regarding the understanding of its mechanisms of action, the benefit and safety of capsaicinoids' pharmacological use remain subjects of discussion, since CAP also promotes epithelial-mesenchymal transition, in an ambivalence that has been referred to as "the double-edge sword". Here, we update the comparative discussion of relevant reports about capsaicinoids' bioactivity in a plethora of experimental models of cancer in terms of selectivity, efficacy, and safety. Through an integration of the underlying mechanisms, as well as inherent aspects of cancer biology, we propose mechanistic models regarding the dichotomy of their effects. Finally, we discuss a selection of in vivo evidence concerning capsaicinoids' immunomodulatory properties against cancer.

Are We Ready to Recommend Capsaicin for Disorders Other Than Neuropathic Pain?

Capsaicin, a lipophilic, volatile compound, is responsible for the pungent properties of chili peppers. In recent years, a significant increase in investigations into its properties has allowed the production of new formulations and the development of tools with biotechnological, diagnostic, and potential therapeutic applications. Most of these studies show beneficial effects, improving antioxidant and anti-inflammatory status, inducing thermogenesis, and reducing white adipose tissue. Other mechanisms, including reducing food intake and improving intestinal dysbiosis, are also described. In this way, the possible clinical application of such compound is expanding every year. This opinion article aims to provide a synthesis of recent findings regarding the mechanisms by which capsaicin participates in the control of non-communicable diseases such as obesity, diabetes, and dyslipidemia.

Dietary Capsaicin Reduces Chemically Induced Rat Urinary Bladder Carcinogenesis

Capsaicin (CAP) is the compound responsible for pungency in chili peppers, presenting several biological properties. But its general safety and effectiveness in the context of carcinogenesis has not been fully clarified. Thus, the present study evaluated whether dietary CAP modifies the development of urothelial lesions induced by the carcinogen N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in male Sprague-Dawley rats. Animals were randomly allocated into 6 groups: G1 - treated with 0.05% BBN in drinking water (weeks 1-12) and received a balanced diet (weeks 1-20); G2 and G3-treated with BBN (weeks 1-12) and received a balanced diet with 0.01 or 0.02% CAP (weeks 1-20), respectively; G4 and G5- only received a balanced diet with 0.01 or 0.02% CAP (weeks 1-20), respectively; G6 - only received a balanced diet (weeks 1-20). At the end of week 20, the incidence and types of urothelial lesions, proliferating cell nuclear antigen (PCNA) labeling index, and matrix metalloproteinases (MMP) 2 and 9 activities were analyzed. A significant reduction was observed in the incidence and multiplicity of simple (p = 0.020 and p = 0.011) and nodular/papillary (p = 0.030 and p = 0.003) hyperplasias and papillomas/carcinomas (p = 0.023 and p = 0.020), epithelial proliferation (p = 0.007) and in the activity of the intermediate form of MMP-2 (p < 0.001) and pro-MMP-9 activities (p < 0.002), in BBN + 0.02% CAP (G3) group in comparison to BBN (G1) group. Capsaicin intake per se did not alter body weight, liver and kidney weights, urothelial histology or serum biochemical parameters. Thus, dietary CAP was safe and showed a protective effect against rat BBN-induced urothelial carcinogenesis.

Biomedical and Antioxidant Potentialities in Chilli: Perspectives and Way Forward

Worldwide, since ages and nowadays, traditional medicine is well known, owing to its biodiversity, which immensely contributed to the advancement and development of complementary and alternative medicines. There is a wide range of spices, herbs, and trees known for their medicinal uses. Chilli peppers, a vegetable cum spice crop, are bestowed with natural bioactive compounds, flavonoids, capsaicinoids, phytochemicals, phytonutrients, and pharmacologically active compounds with potential health benefits. Such compounds manifest their functionality over solo-treatment by operating in synergy and consortium. Co-action of these compounds and nutrients make them potentially effective against coagulation, obesity, diabetes, inflammation, dreadful diseases, such as cancer, and microbial diseases, alongside having good anti-oxidants with scavenging ability to free radicals and oxygen. In recent times, capsaicinoids especially capsaicin can ameliorate important viral diseases, such as SARS-CoV-2. In addition, capsaicin provides an ability to chilli peppers to ramify as topical agents in pain-relief and also benefitting man as a potential effective anesthetic agent. Such phytochemicals involved not only make them useful and a much economical substitute to wonder/artificial drugs but can be exploited as obscene drugs for the production of novel stuffs. The responsibility of the TRPV1 receptor in association with capsaicin in mitigating chronic diseases has also been justified in this study. Nonetheless, medicinal studies pertaining to consumption of chilli peppers are limited and demand confirmation of the findings from animal studies. In this artifact, an effort has been made to address in an accessible format the nutritional and biomedical perspectives of chilli pepper, which could precisely upgrade and enrich our pharmaceutical industries towards human well-being.

Capsaicin: A Two-Decade Systematic Review of Global Research Output and Recent Advances Against Human Cancer

Capsaicin (8-methyl-N-vanillyl-6-nonenamide) is one of the most important natural products in the genus Capsicum. Due to its numerous biological effects, there has been extensive and increasing research interest in capsaicin, resulting in increased scientific publications in recent years. Therefore, an in-depth bibliometric analysis of published literature on capsaicin from 2001 to 2021 was performed to assess the global research status, thematic and emerging areas, and potential insights into future research. Furthermore, recent research advances of capsaicin and its combination therapy on human cancer as well as their potential mechanisms of action were described. In the last two decades, research outputs on capsaicin have increased by an estimated 18% per year and were dominated by research articles at 93% of the 3753 assessed literature. In addition, anti-cancer/pharmacokinetics, cytotoxicity, in vivo neurological and pain research studies were the keyword clusters generated and designated as thematic domains for capsaicin research. It was evident that the United States, China, and Japan accounted for about 42% of 3753 publications that met the inclusion criteria. Also, visibly dominant collaboration nodes and networks with most of the other identified countries were established. Assessment of the eligible literature revealed that the potential of capsaicin for mitigating cancer mainly entailed its chemo-preventive effects, which were often linked to its ability to exert multi-biological effects such as anti-mutagenic, antioxidant and anti-inflammatory activities. However, clinical studies were limited, which may be related to some of the inherent challenges associated with capsaicin in the limited clinical trials. This review presents a novel approach to visualizing information about capsaicin research and a comprehensive perspective on the therapeutic significance and applications of capsaicin in the treatment of human cancer.

Molecular relation between biological stress and carcinogenesis

This paper aims to overview different types of stress, including DNA replication stress, oxidative stress, and psychological stress. Understanding the processes that constitute a cellular response to varied types of stress lets us find differences in how normal cells and cancer cells react to the appearance of a particular kind of stressor. The revealed dissimilarities are the key for targeting new molecules and signaling pathways in anticancer treatment. For this reason, molecular mechanisms that underlay DNA replication stress, oxidative stress, and psychological stress have been studied and briefly presented to indicate biochemical points that make stressors contribute to cancer development. What is more, the viewpoint in which cancer constitutes the outcome and the cause of stress has been taken into consideration. In a described way, this paper draws attention to the problem of cancer-related post-traumatic stress disorder and proposes a novel, multidimensional oncological approach, connecting anticancer treatment with psychiatric support.

Transient Receptor Potential Cation Channel Subfamily V Member 1 Expression Promotes Chemoresistance in Non-Small-Cell Lung Cancer

Approximately 85% of lung cancer cases are non-small-cell lung cancer (NSCLC). Chemoresistance is a leading cause of chemotherapy failure in NSCLC treatment. Transient receptor potential cation channel subfamily V, member 1 (TRPV1), a non-selective cation channel, plays multiple roles in tumorigenesis and tumor development, including tumor cell proliferation, death, and metastasis as well as the response to therapy. In this study, we found TRPV1 expression was increased in NSCLC. TRPV1 overexpression induced cisplatin (DDP) and fluorouracil (5-FU) resistance in A549 cells independent of its channel function. TRPV1 expression was upregulated in A549-DDP/5-FU resistant cells, and DDP/5-FU sensitivity was restored by TRPV1 knockdown. TRPV1 overexpression mediated DDP and 5-FU resistance by upregulation of ABCA5 drug transporter gene expression, thereby increasing drug efflux, enhancing homologous recombination (HR) DNA repair pathway to alleviate apoptosis and activating IL-8 signaling to promote cell survival. These findings demonstrate an essential role of TRPV1 in chemoresistance in NSCLC and implicate TRPV1 as a potential chemotherapeutic target.

Antioxidant, Anti-Obesity, Nutritional and Other Beneficial Effects of Different Chili Pepper: A Review

Fruits and vegetables are important components of a healthy diet. They are rich sources of vitamins and minerals, dietary fibre and a host of beneficial non-nutrient substances including plant sterols, flavonoids and other antioxidants. It has been reported that reduced intake of fruits and vegetables may increase the risk of non-communicable diseases (NCDs). Chili pepper, is a common and important spice used to enhance taste and nutrition. Over the years, reports have shown its potential as antioxidant and an anti-obesity agent. Obesity is a serious health concern as it may initiate other common chronic diseases. Due to the side effects of synthetic antioxidants and anti-obesity drugs, scientists are now focusing on natural products which produce similar effects to synthetic chemicals. This up-to-date review addresses this research gap and presents, in an accessible format, the nutritional, antioxidant and anti-obesity properties of different chili peppers. This review article serves as a reference guide for use of chili peppers as anti-obesity agents.

Oral Capsaicinoid Administration Alters the Plasma Endocannabinoidome and Fecal Microbiota of Reproductive-Aged Women Living with Overweight and Obesity

Capsaicinoids, the pungent principles of chili peppers and prototypical activators of the transient receptor potential of the vanilloid type-1 (TRPV1) channel, which is a member of the expanded endocannabinoid system known as the endocannabinoidome (eCBome), counteract food intake and obesity. In this exploratory study, we examined the blood and stools from a subset of the participants in a cohort of reproductive-aged women with overweight/obesity who underwent a 12-week caloric restriction of 500 kcal/day with the administration of capsaicinoids (two capsules containing 100 mg of a capsicum annuum extract (CAE) each for a daily dose of 4 mg of capsaicinoids) or a placebo. Samples were collected immediately before and after the intervention, and plasma eCBome mediator levels (from 23 participants in total, 13 placebo and 10 CAE) and fecal microbiota taxa (from 15 participants in total, 9 placebo and 6 CAE) were profiled using LC-MS/MS and 16S metagenomic sequencing, respectively. CAE prevented the reduced caloric-intake-induced decrease in beneficial eCBome mediators, i.e., the TRPV1, GPR119 and/or PPARα agonists, N-oleoyl-ethanolamine, N-linoleoyl-ethanolamine and 2-oleoyl-glycerol, as well as the anti-inflammatory N-acyl-ethanolamines N-docosapentaenyl-ethanolamine and N-docosahexaenoyl-ethanolamine. CAE produced few but important alterations in the fecal microbiota, such as an increased relative abundance of the genus Flavonifractor, which is known to be inversely associated with obesity. Correlations between eCBome mediators and other potentially beneficial taxa were also observed, thus reinforcing the hypothesis of the existence of a link between the eCBome and the gut microbiome in obesity.

Capsaicin Potentiates Anticancer Drug Efficacy Through Autophagy-Mediated Ribophorin II Downregulation and Necroptosis in Oral Squamous Cell Carcinoma Cells

The ability of capsaicin co-treatment to sensitize cancer cells to anticancer drugs has been widely documented, but the detailed underlying mechanisms remain unknown. In addition, the role of ribophorin II turnover on chemosensitization is still uncertain. Here, we investigated capsaicin-induced sensitization to chemotherapeutic agents in the human oral squamous carcinoma cell lines, HSC-3 and SAS. We found that capsaicin (200 μM) did not induce remarkable apoptotic cell death in these cell lines; instead, it significantly enhanced autophagy with a concomitant decrease of ribophorin II protein. This capsaicin-induced decrease in ribophorin II was intensified by the autophagy inducer, rapamycin, but attenuated by the autophagy inhibitors, ULK1 inhibitor and chloroquine, indicating that the autophagic process was responsible for the capsaicin-induced down-regulation of ribophorin II. Co-administration of capsaicin with conventional anticancer agents did, indeed, sensitize the cancer cells to these agents. In co-treated cells, the induction of apoptosis was significantly reduced and the levels of the necroptosis markers, phospho-MLKL and phospho-RIP3, were increased relative to the levels seen in capsaicin treatment alone. The levels of DNA damage response markers were also diminished by co-treatment. Collectively, our results reveal a novel mechanism by which capsaicin sensitizes oral cancer cells to anticancer drugs through the up-regulation of autophagy and down-regulation of ribophorin II, and further indicate that the induction of necroptosis is a critical factor in the capsaicin-mediated chemosensitization of oral squamous carcinoma cells to conventional anticancer drugs.

The Impact of TRPV1 on Cancer Pathogenesis and Therapy: A Systematic Review

The transient receptor potential cation channel subfamily V member 1 (TRPV1) is a transmembrane protein that can be activated by various physical and chemical stimuli and is associated with pain transduction. In recent years, TRPV1 was discovered to play essential roles in cancer tumorigenesis and development, as TRPV1 expression levels are altered in numerous cancer cell types. Several investigations have discovered direct associations between TRPV1 and cancer cell proliferation, cell death, and metastasis. Furthermore, about two dozen TRPV1 agonists/antagonists are under clinical trial, as TRPV1 is a potential drug target for treating various diseases. Hence, more researchers are focusing on the effects of TRPV1 agonists or antagonists on cancer tumorigenesis and development. However, both agonists and antagonists may reveal anti-cancer effects, and the effect may function via or be independent of TRPV1. In this review, we provide an overview of the impact of TRPV1 on cancer cell proliferation, cell death, and metastasis, as well as on cancer therapy and the tumor microenvironment, and consider the implications of using TRPV1 agonists and antagonists for future research and potential therapeutic approaches.

Natural Bioactive Compounds as Potential Browning Agents in White Adipose Tissue

The epidemic of overweight and obesity underlies many common metabolic diseases. Approaches aimed to reduce energy intake and/or stimulate energy expenditure represent potential strategies to control weight gain. Adipose tissue is a major energy balancing organ. It can be classified as white adipose tissue (WAT) and brown adipose tissue (BAT). While WAT stores excess metabolic energy, BAT dissipates it as heat via adaptive thermogenesis. WAT also participates in thermogenesis by providing thermogenic fuels and by directly generating heat after browning. Browned WAT resembles BAT morphologically and metabolically and is classified as beige fat. Like BAT, beige fat can produce heat. Human adults have BAT-like or beige fat. Recruitment and activation of this fat type have the potential to increase energy expenditure, thereby countering against obesity and its metabolic complications. Given this, agents capable of inducing WAT browning have recently attracted broad attention from biomedical, nutritional and pharmaceutical societies. In this review, we summarize natural bioactive compounds that have been shown to promote beige adipocyte recruitment and activation in animals and cultured cells. We also discuss potential molecular mechanisms for each compound to induce adipose browning and metabolic benefits.

Recovery of Capsaicinoids and Other Phytochemicals Involved With TRPV-1 Receptor to Re-valorize Chili Pepper Waste and Produce Nutraceuticals

The hot chili pepper industry represents one of the most important staple foods in Mexico and many Asian countries. Nowadays, large amounts of waste materials are produced from the pepper supply chain that could be used as a source to obtain nutraceuticals. Among the most common and important bioactive compounds contained in pepper residues are the capsaicinoids, which are the responsible of the pungency of the pepper. Capsaicinoids, mainly capsaicin, may ameliorate obesity, gastric disorder, diabetes, cardiovascular diseases, cancer, rhinitis, asthma, immune system diseases, and important viral diseases as the recent COVID-19. The aim of this review is to review the industrial process for the extraction of capsaicinoids ingredients from pepper residues and to examine the relation of the capsaicin and other chili pepper phytochemicals to prevent and treat chronic diseases explained through the key role of the TRPV1 receptor. The extraction and incorporation of these compounds into nutraceutical formulations depend mainly on the development of new methods to improve not only the yield of a particular compound but the validation of the bioactivity and phytochemical characterization.

Hydrogen Sulfide-Evoked Intracellular Ca2+ Signals in Primary Cultures of Metastatic Colorectal Cancer Cells

Simple Summary

Colorectal cancer (CRC) is the most common type of gastrointestinal cancer and the third most predominant cancer in the world. CRC is potentially curable with surgical resection of the primary tumor. The clinical problem of colorectal cancer, however, is the spread and outgrowth of metastases, which are difficult to eradicate and lead to a patient’s death. The failure of conventional treatment to significantly improved outcomes in mCRC has prompted the search for alternative molecular targets with the goal of ameliorating the prognosis of these patients. The present investigation revealed that exogenous delivery of hydrogen sulfide (H₂S) suppresses proliferation in metastatic colorectal cancer cells by inducing an increase in intracellular Ca²⁺ concentration. H₂S was effective on metastatic, but not normal, cells. Therefore, we propose that exogenous administration of H₂S to patients affected by metastatic colorectal carcinoma could represent a promising therapeutic alternative.

Abstract

Exogenous administration of hydrogen sulfide (H₂S) is emerging as an alternative anticancer treatment. H₂S-releasing compounds have been shown to exert a strong anticancer effect by suppressing proliferation and/or inducing apoptosis in several cancer cell types, including colorectal carcinoma (CRC). The mechanism whereby exogenous H₂S affects CRC cell proliferation is yet to be clearly elucidated, but it could involve an increase in intracellular Ca²⁺ concentration ([Ca²⁺]_i). Herein, we sought to assess for the first time whether (and how) sodium hydrosulfide (NaHS), one of the most widely employed H₂S donors, induced intracellular Ca²⁺ signals in primary cultures of human metastatic CRC (mCRC) cells. We provided the evidence that NaHS induced extracellular Ca²⁺ entry in mCRC cells by activating the Ca²⁺-permeable channel Transient Receptor Potential Vanilloid 1 (TRPV1) followed by the Na⁺-dependent recruitment of the reverse-mode of the Na⁺/Ca²⁺ (NCX) exchanger. In agreement with these observations, TRPV1 protein was expressed and capsaicin, a selective TRPV1 agonist, induced Ca²⁺ influx by engaging both TRPV1 and NCX in mCRC cells. Finally, NaHS reduced mCRC cell proliferation, but did not promote apoptosis or aberrant mitochondrial depolarization. These data support the notion that exogenous administration of H₂S may prevent mCRC cell proliferation through an increase in [Ca²⁺]_i, which is triggered by TRPV1.

Exploring the Therapeutic Potential of Membrane Transport Proteins: Focus on Cancer and Chemoresistance

Improving the therapeutic efficacy of conventional anticancer drugs represents the best hope for cancer treatment. However, the shortage of druggable targets and the increasing development of anticancer drug resistance remain significant problems. Recently, membrane transport proteins have emerged as novel therapeutic targets for cancer treatment. These proteins are essential for a plethora of cell functions ranging from cell homeostasis to clinical drug toxicity. Furthermore, their association with carcinogenesis and chemoresistance has opened new vistas for pharmacology-based cancer research. This review provides a comprehensive update of our current knowledge on the functional expression profile of membrane transport proteins in cancer and chemoresistant tumours that may form the basis for new cancer treatment strategies.

MKP-1 overexpression is associated with chemoresistance in bladder cancer via the MAPK pathway

Mitogen activated protein kinase phosphatase-1 (MKP-1) has been revealed to be overexpressed in bladder cancer, particularly in non-muscle invasive bladder cancer. MKP-1 may also be associated with chemotherapy resistance. However, the underlying mechanism is yet to be elucidated. The current study investigated the expression of MKP-1 by performing immunohistochemistry in surgically resected specimens obtained from primary and recurrent patients with bladder cancer. The results revealed that MKP-1 expression increased in recurrent patients. Additionally, a 3D model of the human bladder cancer cell line, RT112, was established to determine the role of MKP-1 in drug resistance. The results demonstrated that MKP-1 overexpression protected bladder cancer cells against cell death. Contrarily, MKP-1 knockdown was revealed to sensitize cells to death. In addition, the application of MAPK inhibitors effectively increased RT112 cell sensitivity to pirarubicin. In conclusion, the results of the current study indicated that MKP-1 treatment resulted in bladder cancer cell chemoresistance via JNK, ERK and p38 pathways. MKP-1 may also serve as a potential therapeutic target for chemoresistance in patients with bladder cancer.

Calcium Entry through TRPV1: A Potential Target for the Regulation of Proliferation and Apoptosis in Cancerous and Healthy Cells

Intracellular calcium (Ca2+) concentration ([Ca2+]i) is a key determinant of cell fate and is implicated in carcinogenesis. Membrane ion channels are structures through which ions enter or exit the cell, depending on the driving forces. The opening of transient receptor potential vanilloid 1 (TRPV1) ligand-gated ion channels facilitates transmembrane Ca2+ and Na+ entry, which modifies the delicate balance between apoptotic and proliferative signaling pathways. Proliferation is upregulated through two mechanisms: (1) ATP binding to the G-protein-coupled receptor P2Y2, commencing a kinase signaling cascade that activates the serine-threonine kinase Akt, and (2) the transactivation of the epidermal growth factor receptor (EGFR), leading to a series of protein signals that activate the extracellular signal-regulated kinases (ERK) 1/2. The TRPV1-apoptosis pathway involves Ca2+ influx and efflux between the cytosol, mitochondria, and endoplasmic reticulum (ER), the release of apoptosis-inducing factor (AIF) and cytochrome c from the mitochondria, caspase activation, and DNA fragmentation and condensation. While proliferative mechanisms are typically upregulated in cancerous tissues, shifting the balance to favor apoptosis could support anti-cancer therapies. TRPV1, through [Ca2+]i signaling, influences cancer cell fate; therefore, the modulation of the TRPV1-enforced proliferation-apoptosis balance is a promising avenue in developing anti-cancer therapies and overcoming cancer drug resistance. As such, this review characterizes and evaluates the role of TRPV1 in cell death and survival, in the interest of identifying mechanistic targets for drug discovery.

Progress in understanding role of capsaicin in prevention and treatment of digestive system tumors

Radiation and chemotherapy are still the main treatments for malignant tumors, but their side effects are significant. Thus, searching natural active substances for the prevention and treatment of tumor has attracted wide attention. Capsaicin (Cap) is the main active ingredient in chili hot material. Since the 20th century, more and more studies have been performed on the clinical effects of Cap, and its antitumor function has become a currently hot research topic. The antitumor mechanism of Cap is complex, and it can cause tumor cell proliferation inhibition, apoptosis, and autophagy, inhibit tumor cell migration and invasion, and have an anti-angiogenesis property. As a potential anti-tumor drug, Cap has a broad prospect to increase the efficacy of other chemotherapy drugs. This paper reviews the role of Cap in the prevention and treatment of digestive system tumors and discusses the possible mechanisms involved.

Removal of anthracycline cytostatics from aquatic environment: Comparison of nanocrystalline titanium dioxide and decontamination agents

Anthracyclines are a class of pharmaceuticals used in cancer treatment have the potential to negatively impact the environment. To study the possibilities of anthracyclines (represented by pirarubicin and valrubicin) removal, chemical inactivation using NaOH (0.01 M) and NaClO (5%) as decontamination agents and adsorption to powdered nanocrystalline titanium dioxide (TiO2) were compared. The titanium dioxide (TiO2) nanoparticles were prepared via homogeneous precipitation of an aqueous solution of titanium (IV) oxy-sulfate (TiOSO4) at different amount (5-120 g) with urea. The as-prepared TiO2 samples were characterized by XRD, HRSEM and nitrogen physisorption. The adsorption process of anthracycline cytostatics was determined followed by high-performance liquid chromatography coupled with mass spectrometry (LC-MS) and an in-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) technique. It was found that NaClO decomposes anthracyclines to form various transformation products (TPs). No TPs were identified after the reaction of valrubicin with a NaOH solution as well as in the presence of TiO2 nanoparticles. The best degree of removal, 100% of pirarubicin and 85% of valrubicin, has been achieved in a sample with 120 grams of TiOSO4 (TIT120) and TiO2 with 60 grams (TIT60), respectively.

The Mediterranean Diet as source of bioactive compounds with multi-targeting anti-cancer profile

Many bioactive agents have been extracted from plants or belong to functional foods and have been considered in the treatment of serious and multifactorial diseases, such as cancer. In particular, this review is focused on the anti-cancer properties owned by several natural products typically from the Mediterranean area. In some regions of the South of Italy, a lower cancer incidence has been observed. There is increasing evidence that adherence to a Mediterranean dietary pattern correlates with reduced risk of several cancer types. This could be mainly attributed to the typical lifestyle aspects of the Mediterranean diet, such as high consumption of fruit and vegetables. In this review, the main natural products of the Mediterranean area are discussed, with particular attention on their anti-cancer properties endowed with multi-target profiles.

Capsaicinoids enhance chemosensitivity to chemotherapeutic drugs

Cytotoxic chemotherapy is the mainstay of cancer treatment. Conventional chemotherapeutic agents do not distinguish between normal and neoplastic cells. This leads to severe toxic side effects, which may necessitate the discontinuation of treatment in some patients. Recent research has identified key molecular events in the initiation and progression of cancer, promoting the design of targeted therapies to selectively kill tumor cells while sparing normal cells. Although, the side effects of such drugs are typically milder than conventional chemotherapies, some off-target effects still occur. Another serious challenge with all chemotherapies is the acquisition of chemoresistance upon prolonged exposure to the drug. Therefore, identifying supplementary agents that sensitize tumor cells to chemotherapy-induced apoptosis and help minimize drug resistance would be valuable for improving patient tolerance and response to chemotherapy. The use of effective supplementary agents provides a twofold advantage in combination with standard chemotherapy. First, by augmenting the activity of the chemotherapeutic drug it can lower the dose needed to kill tumor cells and decrease the incidence and severity of treatment-limiting side effects. Second, adjuvant therapies that lower the effective dose of chemotherapy may delay/prevent the development of chemoresistance in tumors. Capsaicinoids, a major class of phytochemical compounds isolated from chili peppers, have been shown to improve the efficacy of several anti-cancer drugs in cell culture and animal models. The present chapter summarizes the current knowledge about the chemosensitizing activity of capsaicinoids with conventional and targeted chemotherapeutic drugs, highlighting the potential use of capsaicinoids in novel combination therapies to improve the therapeutic indices of conventional and targeted chemotherapeutic drugs in human cancers.

Combination of the natural product capsaicin and docetaxel synergistically kills human prostate cancer cells through the metabolic regulator AMP-activated kinase

Background

Current chemotherapy for castration-resistant prostate cancer is established on taxane-based compounds like docetaxel. However, eventually, the development of toxic side effects and resistance limits the therapeutic benefit being the major concern in the treatment of prostate cancer. Combination therapies in many cases, enhance drug efficacy and delay the appearance of undesired effects, representing an important option for the treatment of castration-resistant prostate cancer. In this study, we tested the efficacy of the combination of docetaxel and capsaicin, the pungent ingredient of hot chili peppers, on prostate cancer cells proliferation.

Methods

Prostate cancer LNCaP and PC3 cell lines were used in this study. Levels of total and phosphorylated forms of Akt, mTOR, S6, LKB1, AMPK and ACC were determined by Western blot. AMPK, LKB1 and Akt knock down was performed by siRNA. PTEN was overexpressed by transient transfection with plasmids. Xenograft prostate tumors were induced in nude mice and treatments (docetaxel and capsaicin) were administered intraperitoneally. Statistical analyses were performed with GraphPad software. Combination index was calculated with Compusyn software.

Results

Docetaxel and capsaicin synergistically inhibited the growth of LNCaP and PC3 cells, with a combination index lower than 1 for most of the combinations tested. Co-treatment with docetaxel and capsaicin notably decreased Akt and its downstream targets mTOR and S6 phosphorylation. Overexpression of PTEN phosphatase abrogated the synergistic antiproliferative effect of docetaxel and capsaicin. The combined treatment also increased the phosphorylation of AMP-activated kinase (AMPK) and the phosphorylation of its substrate ACC. In addition, pharmacological inhibition of AMPK with dorsomorphin (compound C) as well as knock down by siRNA of AMPK or its upstream kinase LKB1, abolished the synergy of docetaxel and capsaicin. Mechanistically, we showed that the synergistic anti-proliferative effect may be attributed to two independent effects: Inhibition of the PI3K/Akt/mTOR signaling pathway by one side, and AMPK activation by the other. In vivo experiments confirmed the synergistic effects of docetaxel and capsaicin in reducing the tumor growth of PC3 cells.

Conclusion

Combination of docetaxel and capsaicin represents a therapeutically relevant approach for the treatment of Prostate Cancer.

Capsaicin inhibits the metastasis of human papillary thyroid carcinoma BCPAP cells through the modulation of the TRPV1 channel

Capsaicin (CAP), a potent transient receptor potential vanilloid type 1 (TRPV1) agonist, is a major ingredient of red pepper. Recently, capsaicin has attracted increasing attention owing to its multiple biological activities. However, the anticancer effects of capsaicin against various types of cancers, especially on thyroid carcinoma, have not been completely elucidated. TRPV1, which can be activated by capsaicin, plays a key role in many biological and physiological processes. In the present study, the anticancer properties of capsaicin against papillary thyroid cancer BCPAP cells were investigated. Our results indicated that TRPV1 and TRPV6 were universally expressed in different types of thyroid cell lines. Capsaicin could inhibit multiple steps of metastasis without affecting the viability of BCPAP cells. The activation of TRPV1 by capsaicin (25-100 μM) significantly suppressed the migration and invasion of BCPAP cells as well as their adhesion. The protein levels of Snail1 and Twist1, two critical EMT transcription factors (EMT-TFs), dramatically decreased in a dose-dependent manner after capsaicin treatment, accompanied by the up-regulation of downstream protein E-cadherin. Subsequently, the activation of TRPV1 by capsaicin also caused significant inhibition of the expression of MMP-2 and MMP-9. Moreover, the inhibitory effects of capsaicin on the metastasis of BCPAP cells were abrogated by the pre-treatment of a specific TRPV1 antagonist (capsazepin). Our results suggest that the activation of TRPV1 by capsaicin is associated with the metastatic inhibition of papillary thyroid cancer BCPAP cells, indicating that targeting of TRPV1 functions remains a feasible strategy for cancer treatment.

Static magnetic field enhances the anticancer efficacy of capsaicin on HepG2 cells via capsaicin receptor TRPV1

Static magnetic field (SMF) has shown some possibilities for cancer therapies. In particular, the combinational effect between SMF and anti-cancer drugs has drawn scientists’ attentions in recent years. However, the underlying mechanism for the drug-specific synergistic effect is far from being understood. Besides, the drugs used are all conventional chemotherapy drugs, which may cause unpleasant side effects. In this study, our results demonstrate for the first time that SMF could enhance the anti-cancer effect of natural compound, capsaicin, on HepG2 cancer cells through the mitochondria-dependent apoptosis pathway. We found that the synergistic effect could be due to that SMF increased the binding efficiency of capsaicin for the TRPV1 channel. These findings may provide a support to develop an application of SMF for cancer therapy. The present study offers the first trial in combining SMF with natural compound on anti-cancer treatment, which provides additional insight into the interaction between SMF and anti-cancer drugs and opens the door for the development of new strategies in fighting cancer with minimum cytotoxicity and side effects.

Prostanoid-dependent bladder pain caused by proteinase-activated receptor-2 activation in mice: Involvement of TRPV1 and T-type Ca2+ channels

We studied the pronociceptive role of proteinase-activated receptor-2 (PAR2) in mouse bladder. In female mice, intravesical infusion of the PAR2-activating peptide, SLIGRL-amide (SL), caused delayed mechanical hypersensitivity in the lower abdomen, namely 'referred hyperalgesia', 6-24 h after the administration. The PAR2-triggered referred hyperalgesia was prevented by indomethacin or a selective TRPV1 blocker, and restored by a T-type Ca²⁺ channel blocker. In human urothelial T24 cells, SL caused delayed prostaglandin E₂ production and COX-2 upregulation. Our data suggest that luminal PAR2 stimulation in the bladder causes prostanoid-dependent referred hyperalgesia in mice, which involves the activation of TRPV1 and T-type Ca²⁺ channels.

Dietary capsaicin and its anti-obesity potency: from mechanism to clinical implications

Obesity is a growing public health problem, which has now been considered as a pandemic non-communicable disease. However, the efficacy of several approaches for weight loss is limited and variable. Thus, alternative anti-obesity treatments are urgently warranted, which should be effective, safe, and widely available. Active compounds isolated from herbs are similar with the practice of Traditional Chinese Medicine, which has a holistic approach that can target to several organs and tissues in the whole body. Capsaicin, a major active compound from chili peppers, has been clearly demonstrated for its numerous beneficial roles in health. In this review, we will focus on the less highlighted aspect, in particular how dietary chili peppers and capsaicin consumption reduce body weight and its potential mechanisms of its anti-obesity effects. With the widespread pandemic of overweight and obesity, the development of more strategies for the treatment of obesity is urgent. Therefore, a better understanding of the role and mechanism of dietary capsaicin consumption and metabolic health can provide critical implications for the early prevention and treatment of obesity.

Applicability of electrospun polypropylene carbonate polymers as a drug carrier for sirolimus

Polypropylene carbonate (PPC), a biodegradable aliphatic polyester, exhibits one particular advantage over other polyesters, which is that following degradation in vivo, it primarily produces H2O and CO2, causing minimal side effects. Although PPC exhibits limited mechanical strength, and is therefore not able to serve as a scaffold to support tissue regeneration, it may be suitable for drug delivery; however, this requires further investigation. In the present study, electrospinning was applied to generate PPC polymers containing sirolimus, a cell growth‑inhibiting drug which is used to treat restenosis. The properties of PPC‑sirolimus polymers were examined using scanning electron microscopy, differential scanning calorimetry and in vitro degradation assays. Drug loading and entrapment efficiency were determined, and in vitro sirolimus‑release from the polymer was assessed. Furthermore, the effect of PPC‑sirolimus polymers on cell growth was measured using an MTT assay in vitro. The results of the present study demonstrated that electrospun PPC polymers formed a uniform three‑dimensional, grid‑intertwined, net‑like structure; the surface of the polymers was smooth and the diameter was ~3 µm. Differential scanning calorimetry analysis demonstrated that sirolimus existed in an amorphous state in the polymer. Following soaking in PBS for 4 weeks, the polymer swelled and the net‑like structure broke down and fragmented. Sirolimus loading and entrapment efficiency were 10.3±3.2 and 95.1±10.6%, respectively. Sirolimus‑release from PPC‑sirolimus polymers continued for 28 days in PBS. PPC‑sirolimus markedly inhibited the growth of rat aortic adventitial fibroblast cells, an effect which was not observed with PPC alone. The results of the present study suggest that PPC polymers are a promising alternative drug carrier for sirolimus.

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.

Capsaicin synergizes with camptothecin to induce increased apoptosis in human small cell lung cancers via the calpain pathway

Small cell lung cancer (SCLC) is characterized by excellent initial response to chemotherapy and radiation therapy with a majority of the patients showing tumor shrinkage and even remission. However, the challenge with SCLC therapy is that patients inevitably relapse and subsequently do not respond to the first line treatment. Recent clinical studies have investigated the possibility of camptothecin-based combination therapy as first line treatment for SCLC patients. Conventionally, camptothecin is used for recurrent SCLC and has poor survival outcomes. Therefore, drugs which can improve the therapeutic index of camptothecin should be valuable for SCLC therapy. Extensive evidence shows that nutritional compounds like capsaicin (the spicy compound of chili peppers) can improve the anti-cancer activity of chemotherapeutic drugs in both cell lines and animal models. Statistical analysis shows that capsaicin synergizes with camptothecin to enhance apoptosis of human SCLC cells. The synergistic activity of camptothecin and capsaicin is observed in both classical and variant SCLC cell lines and, in vivo, in human SCLC tumors xenotransplanted on chicken chorioallantoic membrane (CAM) models. The synergistic activity of capsaicin and camptothecin are mediated by elevation of intracellular calcium and the calpain pathway. Our data foster hope for novel nutrition based combination therapies in SCLC.

Expression and functionality of TRPV1 in breast cancer cells

Transient receptor potential (TRP) channels contribute to the regulation of intracellular calcium, which can promote cancer hallmarks in cases of dysregulation of gene transcription and calcium-dependent pro-proliferative or anti-apoptotic mechanisms. Several studies have begun to elucidate the roles of TRPV1, TRPV6, TRPM8, and TRPC1 in cancer progression; however, no study has examined the expression profiles of human TRP channels in breast cancer on a large scale. This study focused on the expression and functionality of TRPV1, a nonselective cation channel that was found to be expressed in different carcinoma tissues. Next-generation sequencing analyses revealed the expression of TRPV1 in several native breast cancer tissues, which was subsequently validated via reverse transcriptase-polymerase chain reaction. Activation of TRPV1 by its ligand capsaicin was associated with the growth inhibition of some cancer cell types; however, the signaling components involved are complex. In this study, stimulation by the TRPV1 agonist, capsaicin, of SUM149PT cells, a model system for the most aggressive breast cancer subtype, triple-negative breast cancer, led to intracellular calcium signals that were diminished by the specific TRPV1 antagonist, capsazepin. Activation of TRPV1 by capsaicin caused significant inhibition of cancer cell growth and induced apoptosis and necrosis. In conclusion, the current study revealed the expression profiles of human TRP channels in 60 different breast cancer tissues and cell lines and furthermore validated the antitumor activity of TRPV1 against SUM149PT breast cancer cells, indicating that activation of TRPV1 could be used as a therapeutic target, even in the most aggressive breast cancer types.

Chili pepper as a body weight-loss food

Chili has culinary as well as medical importance. Studies in humans, using a wide range of doses of chili intake (varying from a single meal to a continuous uptake for up to 12 weeks), concluded that it facilitates weight loss. In regard to this, the main targets of chili are fat metabolism, energy expenditure, and thermogenesis. To induce weight loss, the active substance of chili, capsaicin, activates Transient Receptor Potential Cation Channel sub-family V member 1 (TRPV1) channels) receptors causing an increase in intracellular calcium levels and triggering the sympathetic nervous system. Apart from TRPV1, chili directly reduces energy expenditure by activating Brown Adipose Tissue. Weight loss by chili is also the result of an improved control of insulin, which supports weight management and has positive effects for treatment for diseases like obesity, diabetes and cardiovascular disorders. This review summarizes the major pathways by which chili contributes to ameliorating parameters that help weight management and how the consumption of chili can help in accelerating weight loss through dietary modifications.

Capsaicin Suppresses Cell Proliferation, Induces Cell Cycle Arrest and ROS Production in Bladder Cancer Cells through FOXO3a-Mediated Pathways

Capsaicin (CAP), a highly selective agonist for transient receptor potential vanilloid type 1 (TRPV1), has been widely reported to exhibit anti-oxidant, anti-inflammation and anticancer activities. Currently, several therapeutic approaches for bladder cancer (BCa) are available, but accompanied by unfavorable outcomes. Previous studies reported a potential clinical effect of CAP to prevent BCa tumorigenesis. However, its underlying molecular mechanism still remains unknown. Our transcriptome analysis suggested a close link among calcium signaling pathway, cell cycle regulation, ROS metabolism and FOXO signaling pathway in BCa. In this study, several experiments were performed to investigate the effects of CAP on BCa cells (5637 and T24) and NOD/SCID mice. Our results showed that CAP could suppress BCa tumorigenesis by inhibiting its proliferation both in vitro and in vivo. Moreover, CAP induced cell cycle arrest at G0/G1 phase and ROS production. Importantly, our studies revealed a strong increase of FOXO3a after treatment with CAP. Furthermore, we observed no significant alteration of apoptosis by CAP, whereas Catalase and SOD2 were considerably upregulated, which could clear ROS and protect against cell death. Thus, our results suggested that CAP could inhibit viability and tumorigenesis of BCa possibly via FOXO3a-mediated pathways.