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

Echinatin inhibits the growth and metastasis of human hepatocellular carcinoma cells through p38 and JNK signaling pathways

Hepatocellular carcinoma (HCC) ranks among the most prevalent cancers, with both a high incidence and a significant mortality rate. Clinical medications are highly toxic to patients and prone to resistance. Natural products are highly valued in the development of antitumour drugs. This study aimed to elucidate the anti-HCC ability and potential mechanism of Echinatin (Ecn), a natural existed flavonoid. Our findings revealed that Ecn suppressed the growth, migration, and invasion of HCC cells and demonstrated a superior inhibitory impact on the development of xenograft tumors. Moreover, Ecn was less toxic to mice and had a good drug safety. Mechanistically, Ecn was found to activate p38 and JNK signaling pathways. Accordingly, the suppressive effect of Ecn on HCC cells was attenuated by the introduction of p38 blocker SB203580 and JNK blocker SP600125. Collectively, our research suggests that Ecn might have anti-HCC properties through the activation of p38 and JNK signaling.

Identification of the LCOR-PLCL1 pathway that restrains lipid accumulation and tumor progression in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is the typical pathological subtype of renal cell carcinoma (RCC), representing about 80% of RCC. Reprogramming of lipid metabolism is one of the nonnegligible pathogeneses in ccRCC. Currently, the underlying regulatory mechanisms of lipid metabolism in ccRCC remain inadequately understood. In this study, we performed bioinformatics analyses and experiments both in vivo and in vitro to explore the biological functions and specific mechanisms of the ligand dependent nuclear receptor corepressor LCOR in ccRCC. Mechanistically, RUNX1 was a transcriptional suppressor of PLCL1, LCOR could interact with RUNX1 to relieve RUNX1-mediated repression of PLCL1, leading to increased PLCL1 expression, which, in turn, inhibited the tumor progression and lipid accumulation in ccRCC. Furthermore, PLCL1 decreased lipid accumulation through UCP1-mediated lipid browning and facilitated tumor apoptosis by activating p38 phosphorylation. In conclusion, the LCOR-RUNX1-PLCL1 axis provides a novel molecular mechanism underlying the progression and lipid storage of ccRCC. LCOR modulation represents a potential therapeutic strategy for the treatment in ccRCC.

New options for targeting TRPV1 receptors for cancer treatment: odorous Chinese herbal medicine

Vanilloid1 (TRPV1), a subfamily of transient receptor channels, is one of the non-selective calcium channels, which is a bridge between cellular response and extracellular environmental networks, and is involved in a variety of pathophysiological processes. It is also involved in the process of cancer occurrence and progression, and researchers are revealing its role in cancer. In this paper, we review the expression and significance of TRPV1 receptor in various cancer cell types, the role of TRPV1 in the apoptosis-proliferation balance, cancer cell invasion and metastasis, and tumor micro-environment, with emphasis on the mechanisms by which TRPV1 receptor mediates inflammatory response, immune system, and thus regulates cancer. We discussed the latest directions and current challenges of TRPV1 receptor-targeting therapy for cancer, and summarized the odorous traditional herbs that modulate TRPV1 receptors, with a view to developing anti-tumor drugs targeting TRPV1 receptors in the future.

A review on phytochemicals as combating weapon for multidrug resistance in cancer

One can recognize multidrug resistance (MDR) and residue as a biggest difficulty in cancer specialist. Chemotherapy-resistant cancer may be successfully treated by combining MDR-reversing phytochemicals with anticancer drugs. Though, clinical application of phytochemicals either alone or in conjunction with chemotherapy is still in its early stages or requires more research to determine their safety and efficacy. In this review we highlighted topics related to MDR in cancer, including an introduction to subject, mechanism of action of efflux pump, specific proteins involved in drug resistance, altered drug targets, increased drug metabolism, and potential role of phytochemicals in overcoming drug resistance.

Metal Ion Signaling in Biomedicine

Complex multicellular organisms are composed of distinct tissues involving specialized cells that can perform specific functions, making such life forms possible. Species are defined by their genomes, and differences between individuals within a given species directly result from variations in their genetic codes. While genetic alterations can give rise to disease-causing acquisitions of distinct cell identities, it is now well-established that biochemical imbalances within a cell can also lead to cellular dysfunction and diseases. Specifically, nongenetic chemical events orchestrate cell metabolism and transcriptional programs that govern functional cell identity. Thus, imbalances in cell signaling, which broadly defines the conversion of extracellular signals into intracellular biochemical changes, can also contribute to the acquisition of diseased cell states. Metal ions exhibit unique chemical properties that can be exploited by the cell. For instance, metal ions maintain the ionic balance within the cell, coordinate amino acid residues or nucleobases altering folding and function of biomolecules, or directly catalyze specific chemical reactions. Thus, metals are essential cell signaling effectors in normal physiology and disease. Deciphering metal ion signaling is a challenging endeavor that can illuminate pathways to be targeted for therapeutic intervention. Here, we review key cellular processes where metal ions play essential roles and describe how targeting metal ion signaling pathways has been instrumental to dissecting the biochemistry of the cell and how this has led to the development of effective therapeutic strategies.

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.

Natural Compounds Derived from Plants on Prevention and Treatment of Renal Cell Carcinoma: A Literature Review

Renal cell carcinoma (RCC) accounts for roughly 85% of all malignant kidney cancer. Therapeutic options for RCC have expanded rapidly over the past decade. Targeted therapy and immunotherapy have ushered in a new era of the treatment of RCC, which has facilitated the outcomes of RCC. However, the related adverse effects and drug resistance remain an urgent issue. Natural compounds are optional strategies to reduce mobility. Natural compounds are favored by clinicians and researchers due to their good tolerance and low economic burden. Many studies have explored the anti-RCC activity of natural products and revealed relevant mechanisms. In this article, the chemoprevention and therapeutic potential of natural compounds is reviewed and the mechanisms regarding natural compounds are explored.

Transient receptor potential vanilloid 1 inhibition reduces brain damage by suppressing neuronal apoptosis after intracerebral hemorrhage

Intracerebral hemorrhage (ICH) induces a complex sequence of apoptotic cascades and inflammatory responses, leading to neurological impairment. Transient receptor potential vanilloid 1 (TRPV1), a nonselective cation channel with high calcium permeability, has been implicated in neuronal apoptosis and inflammatory responses. This study used a mouse ICH model and neuronal cultures to examine whether TRPV1 activation exacerbates brain damage and neurological deficits by promoting neuronal apoptosis and neuroinflammation. ICH was induced by injecting collagenase in both wild-type (WT) C57BL/6 mice and TRPV1-/- mice. Capsaicin (CAP; a TRPV1 agonist) or capsazepine (a TRPV1 antagonist) was administered by intracerebroventricular injection 30 min before ICH induction in WT mice. The effects of genetic deletion or pharmacological inhibition of TRPV1 using CAP or capsazepine on motor deficits, histological damage, apoptotic responses, blood-brain barrier (BBB) permeability, and neuroinflammatory reactions were explored. The antiapoptotic mechanisms and calcium influx induced by TRPV1 inactivation were investigated in cultured hemin-stimulated neurons. TRPV1 expression was upregulated in the hemorrhagic brain, and TRPV1 was expressed in neurons, microglia, and astrocytes after ICH. Genetic deletion of TRPV1 significantly attenuated motor deficits and brain atrophy for up to 28 days. Deletion of TRPV1 also reduced brain damage, neurodegeneration, microglial activation, cytokine expression, and cell apoptosis at 1 day post-ICH. Similarly, the administration of CAP ameliorated brain damage, neurodegeneration, brain edema, BBB permeability, and cytokine expression at 1 day post-ICH. In primary neuronal cultures, pharmacological inactivation of TRPV1 by CAP attenuated neuronal vulnerability to hemin-induced injury, suppressed apoptosis, and preserved mitochondrial integrity in vitro. Mechanistically, CAP reduced hemin-stimulated calcium influx and prevented the phosphorylation of CaMKII in cultured neurons, which was associated with reduced activation of P38 and c-Jun NH2-terminal kinase mitogen-activated protein kinase signaling. Our results suggest that TRPV1 inhibition may be a potential therapy for ICH by suppressing mitochondria-related neuronal apoptosis.

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.

Role of TRP channels in carcinogenesis and metastasis: Pathophysiology and regulation by non-coding RNAs

In 2021, David Julius and Ardem Patapoutian received Nobel Prize in Physiology or Medicine for their ground-breaking discoveries in the functional characterization of receptors for temperature and touch. Transient receptor potential (TRP) channels have captivated tremendous appreciation as promising drug targets over the past few years because of central involvement in different cancers. Based on the insights gleaned from decades of high-quality research, basic and clinical scientists have unveiled how Transient receptor potential channels regulated cancer onset and progression. Pioneering studies have sparked renewed interest and researchers have started to scratch the surface of mechanistic role of these channels in wide variety of cancers. In this review we have attempted to provide a summary of most recent updates and advancements made in the biology of these channels in context of cancers. We have partitioned this review into different subsections on the basis of emerging evidence about characteristically distinct role of TRPV (TRPV1, TRPV5), TRPM (TRPM3, TRPM7) and TRPC in cancers. Regulation of TRP channels by non-coding RNAs is also a very exciting area of research which will be helpful in developing a sharper understanding of the multi-step aspects of cancers.

Proton-sensing ion channels, GPCRs and calcium signaling regulated by them: implications for cancer

Extracellular acidification of tumors is common. Through proton-sensing ion channels or proton-sensing G protein-coupled receptors (GPCRs), tumor cells sense extracellular acidification to stimulate a variety of intracellular signaling pathways including the calcium signaling, which consequently exerts global impacts on tumor cells. Proton-sensing ion channels, and proton-sensing GPCRs have natural advantages as drug targets of anticancer therapy. However, they and the calcium signaling regulated by them attracted limited attention as potential targets of anticancer drugs. In the present review, we discuss the progress in studies on proton-sensing ion channels, and proton-sensing GPCRs, especially emphasizing the effects of calcium signaling activated by them on the characteristics of tumors, including proliferation, migration, invasion, metastasis, drug resistance, angiogenesis. In addition, we review the drugs targeting proton-sensing channels or GPCRs that are currently in clinical trials, as well as the relevant potential drugs for cancer treatments, and discuss their future prospects. The present review aims to elucidate the important role of proton-sensing ion channels, GPCRs and calcium signaling regulated by them in cancer initiation and development. This review will promote the development of drugs targeting proton-sensing channels or GPCRs for cancer treatments, effectively taking their unique advantage as anti-cancer drug targets.

Research trends and frontier hotspots of TRPV1 based on bibliometric and visualization analyses

Background

Transient receptor potential vanilloid type1 (TRPV1) is a non-selective cation channel with multiple activation mechanisms, which has received increasing attention since it was first cloned in 1997.

Methods

We used bibliometric and visualization analyses to evaluate the theme trends and knowledge structure of TRPV1 research-papers on TRPV1 from 2002 to 2022 obtained from the Web of Science Core Collection. VOSviewer and CiteSpace were used to analyze authors, institutions, countries, co-cited references, and keywords.

Results

A total of 7413 papers were included. The main research area of TRPV1 was neuroscience; the most published country was the United States, and the University of California, San Francisco, had the highest centrality. Two major collaborative sub-networks were formed between the authors. The distribution of keywords shows that TRPV1 was initially studied extensively, and the recent studies focused on TRPV1 structure and diseases. "Oxidative stress," "TRPV1 structure," "cancer," and "model" have been the research hotspots in recent years.

Conclusions

This research provides valuable information for the study of TRPV1. Disease research was focused on pain, cancer, and neurodegenerative diseases. Both agonists and antagonists of TRPV1 are gradually being used in clinical practice, and acupuncture was effective in treating TRPV1-mediated inflammatory pain. TRPV1 is involved in classical endogenous cannabis system signaling, and new signaling pathways continue to be revealed.

Spice Up Your Kidney: A Review on the Effects of Capsaicin in Renal Physiology and Disease

Capsaicin, the organic compound which attributes the spicy flavor and taste of red peppers and chili peppers, has been extensively studied for centuries as a potential natural remedy for the treatment of several illnesses. Indeed, this compound exerts well-known systemic pleiotropic effects and may thus bring important benefits against various pathological conditions like neuropathic pain, rhinitis, itching, or chronic inflammation. Yet, little is known about the possible biological activity of capsaicin at the kidney level, as this aspect has only been addressed by sparse experimental investigations. In this paper, we aimed to review the available evidence focusing specifically on the effects of capsaicin on renal physiology, as well as its potential benefits for the treatment of various kidney disorders. Capsaicin may indeed modulate various aspects of renal function and renal nervous activity. On the other hand, the observed experimental benefits in preventing acute kidney injury, slowing down the progression of diabetic and chronic kidney disease, ameliorating hypertension, and even delaying renal cancer growth may set the stage for future human trials of capsaicin administration as an adjuvant or preventive therapy for different, difficult-to-treat renal diseases.

The functions and regulatory pathways of S100A8/A9 and its receptors in cancers

Inflammation primarily influences the initiation, progression, and deterioration of many human diseases, and immune cells are the principal forces that modulate the balance of inflammation by generating cytokines and chemokines to maintain physiological homeostasis or accelerate disease development. S100A8/A9, a heterodimer protein mainly generated by neutrophils, triggers many signal transduction pathways to mediate microtubule constitution and pathogen defense, as well as intricate procedures of cancer growth, metastasis, drug resistance, and prognosis. Its paired receptors, such as receptor for advanced glycation ends (RAGEs) and toll-like receptor 4 (TLR4), also have roles and effects within tumor cells, mainly involved with mitogen-activated protein kinases (MAPKs), NF-κB, phosphoinositide 3-kinase (PI3K)/Akt, mammalian target of rapamycin (mTOR) and protein kinase C (PKC) activation. In the clinical setting, S100A8/A9 and its receptors can be used complementarily as efficient biomarkers for cancer diagnosis and treatment. This review comprehensively summarizes the biological functions of S100A8/A9 and its various receptors in tumor cells, in order to provide new insights and strategies targeting S100A8/A9 to promote novel diagnostic and therapeutic methods in cancers.

Ligand-Gated Ion Channels: Prognostic and Therapeutic Implications for Gliomas

Gliomas are common primary brain malignancies that remain difficult to treat due to their overall aggressiveness and heterogeneity. Although a variety of therapeutic strategies have been employed for the treatment of gliomas, there is increasing evidence that suggests ligand-gated ion channels (LGICs) can serve as a valuable biomarker and diagnostic tool in the pathogenesis of gliomas. Various LGICs, including P2X, SYT16, and PANX2, have the potential to become altered in the pathogenesis of glioma, which can disrupt the homeostatic activity of neurons, microglia, and astrocytes, further exacerbating the symptoms and progression of glioma. Consequently, LGICs, including purinoceptors, glutamate-gated receptors, and Cys-loop receptors, have been targeted in clinical trials for their potential therapeutic benefit in the diagnosis and treatment of gliomas. In this review, we discuss the role of LGICs in the pathogenesis of glioma, including genetic factors and the effect of altered LGIC activity on the biological functioning of neuronal cells. Additionally, we discuss current and emerging investigations regarding the use of LGICs as a clinical target and potential therapeutic for gliomas.

Application of plant products in the synthesis and functionalisation of biopolymers

The burning of plastic trash contributes significantly to the problem of air pollution. Consequently, a wide variety of toxic gases get released into the atmosphere. It is of the utmost importance to develop biodegradable polymers that retain the same characteristics as those obtained from petroleum. In order to decrease the effect that these issues have on the world around us, we need to focus our attention on specific alternative sources capable of biodegrading in their natural environments. Biodegradable polymers have garnered much attention since they can break down through the processes carried out by living creatures. Biopolymers' applications are growing due to their non-toxic nature, biodegradability, biocompatibility, and environmental friendliness. In this regard, we examined numerous methods used to manufacture biopolymers and the critical components from which they get their functional properties. In recent years, economic and environmental concerns have reached a tipping point, increasing production based on sustainable biomaterials. This paper examines plant-based biopolymers as a good resource with potential applications in both biological and non-biological sectors. Scientists have devised various biopolymer synthesis and functionalization techniques to maximize its utility in various applications. In conclusion, recent developments in the functionalization of biopolymers through various plant products and their applications are discussed.

Capsaicin inhibits the migration, invasion and EMT of renal cancer cells by inducing AMPK/mTOR-mediated autophagy

Capsaicin (CAP), extracted from Capsicum fruits, has been reported to exhibit antitumor effects in various lines of cancer cells. However, the mechanism underlying its antitumor efficiency is not fully understood. Autophagy is a fundamental self-degradation process of cells that maintains homeostasis and plays a controversial role in tumor initiation and progression. The EMT is defined as a system regulating cells transformed from an epithelial-like phenotype into a mesenchymal phenotype by several internal and external factors, following the metastatic performance of the cells developed. The present study aimed to investigate the potential role of autophagy in CAP-induced antitumor effects in renal cell carcinoma (RCC) 786-O and CAKI-1 cell lines. The results revealed that CAP remarkably inhibited the migration and invasion of RCC cells in vitro and metastasis in vivo. Moreover, we found that the CAP treatment increased the formation of autophagolysosome vacuoles and LC3 yellow and red fluorescent puncta in RCC cells and upregulated the expression of LC3, suggesting that autophagy was induced by CAP in 786-O and CAKI-1 cell lines. Our further results demonstrated that CAP-induced autophagy was mediated by the AMPK/mTOR pathway. In conclusion, our study provides new knowledge of the potential relationship between autophagy and metastasis inhibition induced by CAP, which might be a promising therapeutic strategy in RCC.

Unveiling the Molecular Mechanisms Driving the Capsaicin-Induced Immunomodulatory Effects on PD-L1 Expression in Bladder and Renal Cancer Cell Lines

Simple Summary

Over time, capsaicin (CPS) has been considered both a potential anti-cancer and pro-cancer molecule. Hence, the diversity of CPS functioning has already been established. Now, exploration of its application with immunotherapies might open up a new avenue in cancer therapy. Herein, the application of CPS as an immunoadjuvant to overcome the tumor’s immune-escaping mechanisms or to increase immune checkpoint therapy has been approached. In bladder cancer, the interaction of CPS with its receptor TRPV1 increases PD-L1 expression, promoting a tumorigenic effect and also providing a target for anti-PD-1/PD-L1 immunotherapy. On the contrary, in renal cell carcinoma, CPS downregulates PD-L1 expression in a TRPV1-independent manner, suggesting a potential application of CPS as an immune-adjuvant in this type of cancer.

Abstract

The blockade of the PD-L1/PD-1 immune checkpoint has promising efficacy in cancer treatment. However, few patients with bladder cancer (BC) or renal cell carcinoma (RCC) respond to this approach. Thus, it is important to implement a strategy to stimulate the immune anti-tumor response. In this scenario, our study evaluated the effects of a low capsaicin (CPS) dose in BC and RCC cell lines. Western blot, qRT-PCR and confocal microscopy were used to assess PD-L1 mRNA and protein expression. Alterations to the cellular oxidative status and changes to the antioxidant NME4 levels, mRNA modulation of cytokines, growth factors, transcriptional factors and oncogene, and the activation of Stat1/Stat3 pathways were examined using Western blot, cytofluorimetry and qRT-PCR profiling assays. In BC, CPS triggers an altered stress oxidative-mediated DNA double-strand break response and increases the PD-L1 expression. On the contrary, in RCC, CPS, by stimulating an efficient DNA damage repair response, thus triggering protein carbonylation, reduces the PD-L1 expression. Overall, our results show that CPS mediates a multi-faceted approach. In modulating PD-L1 expression, there is a rationale for CPS exploitation as a stimulus that increases BC cells’ response to immunotherapy or as an immune adjuvant to improve the efficacy of the conventional therapy in RCC patients.

Therapeutic potential of modulation of the ion channel activity of vanilloid receptors TRPV1 in oncological practice

Background. Type 1 vanilloid receptors (TRPV1 ) play an important role in tumoral genesis and cancer development, because the expression levels of TRPV1 change in a lot of types of cancer cells. At present, the regulation of functional activity and sensitivity of TRPV1 is an object of intensive research. Purpose – to characterize the modern concept of therapeutic potential of modulation of the ion channel activity of vanilloid receptors TRPV1 in oncological practice according to the data from open literature sources. Materials and methods. The publications were selected from the following databases: PubMed, EBSCO, Clinical Key, etc. In these publications the data on the ion channels of the transistor receptor potential were elucidated, particularly on type 1 vanilloid receptors, their role in tumoral genesis and the therapeutic potential of the modulation of their activity. Results. Binding of exogenous agonists to the TRPV1 receptor is accompanied by the influx of Ca2+ ions from the cytosol to the cell. It is known that Ca2+ ions are one of the main secondary messengers, since they play an important role in lots of fundamental physiological processes, including cell excitability, vitality, apoptosis and transcription. The disbalance of intracellular flow of Ca2+ is associated with characteristics of different types of cancer. The latest studies have shown that Ca2+ also contributes to certain malignant appearances, such as proliferation, invasion, migration and metastasis. Moreover, TRPV1 activation modulates the apoptosis-proliferation balance through the mechanisms beyond Ca2+ signaling, and in some works TRPV1 role in metastasis of cancer cells is mentioned. Conclusions. Selective TRPV1 activation or the increase in its expression has therapeutic potential, conditioned by pleiotropic influence on the apoptosis-proliferation balance in cancer cells. TRPV1 blockage or reduction of its expression can mitigate hyperalgesia caused by the tumor. In addition, TRPV1 act as biomarkers of a range of cancers (invasive breast carcinoma, epithelial ovarian and cervical cancer).

The Natural Chemotherapeutic Capsaicin Activates AMPK through LKB1 Kinase and TRPV1 Receptors in Prostate Cancer Cells

The natural bioactive compound capsaicin has been reported to have anticancer activity, although the underlying mechanism of action has not been completely clarified. Herein, we investigated the mechanism whereby capsaicin exerts antitumor effects on prostate cancer cells. We found that capsaicin activated AMP-activated kinase (AMPK) and promoted cell death in the LKB1-expressing prostate cancer cell lines LNCaP and PC3, but not in the liver kinase B1 (LKB1)-null cell line DU-145. Capsaicin treatment stimulated LKB1 phosphorylation and activated AMPK in LKB1-expressing cells. In addition, LKB1 silencing in LNCaP and PC3 cells abrogated capsaicin-induced AMPK activation, while the overexpression of LKB1 by lentiviral infection in DU-145 cells induced capsaicin-triggered AMPK phosphorylation. Moreover, the calcium/calmodulin-dependent kinase kinase 2 (CaMKK2) inhibitor STO-609 did not modify the activation of AMPK induced by capsaicin, suggesting a CaMKK2-independent mechanism. Capsaicin-induced LKB1 phosphorylation was dependent on the transient receptor potential cation channel subfamily V member 1 (TRPV1), since TRPV1 knocked down by shRNA abolished LKB1 and AMPK phosphorylation in LKB1-expressing cells. Altogether, our results showed that capsaicin affected AMPK activity in an LKB1- and TRPV1-dependent fashion, linking TRPV1 with cell fate. These data also suggest that capsaicin may be a rational chemotherapeutic option for prostate tumors.

Endocannabinoid System and Tumour Microenvironment: New Intertwined Connections for Anticancer Approaches

The tumour microenvironment (TME) is now recognised as a hallmark of cancer, since tumour:stroma crosstalk supports the key steps of tumour growth and progression. The dynamic co-evolution of the tumour and stromal compartments may alter the surrounding microenvironment, including the composition in metabolites and signalling mediators. A growing number of evidence reports the involvement of the endocannabinoid system (ECS) in cancer. ECS is composed by a complex network of ligands, receptors, and enzymes, which act in synergy and contribute to several physiological but also pathological processes. Several in vitro and in vivo evidence show that ECS deregulation in cancer cells affects proliferation, migration, invasion, apoptosis, and metastatic potential. Although it is still an evolving research, recent experimental evidence also suggests that ECS can modulate the functional behaviour of several components of the TME, above all the immune cells, endothelial cells and stromal components. However, the role of ECS in the tumour:stroma interplay remains unclear and research in this area is particularly intriguing. This review aims to shed light on the latest relevant findings of the tumour response to ECS modulation, encouraging a more in-depth analysis in this field. Novel discoveries could be promising for novel anti-tumour approaches, targeting the microenvironmental components and the supportive tumour:stroma crosstalk, thereby hindering tumour development.

VHL regulates the sensitivity of clear cell renal cell carcinoma to SIRT4-mediated metabolic stress via HIF-1α/HO-1 pathway

Clear cell renal cell carcinomas (ccRCC) reprogram carbon metabolism responses to hypoxia, thereby promoting utilization of glutamine. Recently, sirtuin 4 (SIRT4), a novel molecular has turned out to be related to alternating glutamine metabolism and modulating the tumor microenvironment. However, the role of SIRT4 in ccRCC remains poorly understood. Here, we illustrated that the expression of SIRT4 is markedly reduced in cancerous tissues, and closely associated with malignancy stage, grade, and prognosis. In ccRCC cells, SIRT4 exerted its proapoptotic activity through enhancing intracellular reactive oxygen species (ROS). Heme oxygenase-1 (HO-1) is part of an endogenous defense system against oxidative stress. Nevertheless, overexpression of SIRT4 hindered the upregulation of HO-1 in von Hippel-Lindau (VHL)-proficient cells and repressed its expression in VHL-deficient cells. This discrepancy indicated that competent VHL withstands the inhibitory role of SIRT4 on HIF-1α/HO-1. Functionally, overexpression of HO-1 counteracted the promotional effects of SIRT4 on ROS accumulation and apoptosis. Mechanistically, SIRT4 modulates ROS and HO-1 expression via accommodating p38-MAPK phosphorylation. By contrast, downregulation of p38-MAPK by SB203580 decreased intracellular ROS level and enhanced the expression of HO-1. Collectively, this work revealed a potential role for SIRT4 in the stimulation of ROS and the modulation of apoptosis. SIRT4/HO-1 may act as a potential therapeutic target, especially in VHL-deficient ccRCCs.

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.

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.

Extraction, purification, bioactivity and pharmacological effects of capsaicin: a review

Capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide), a well-known vanilloid, which is the main spicy component in chili peppers, showing several biological activities and the potential applications range from food flavorings to therapeutics. Traditional extraction of capsaicin by organic solvents was time-consuming, some new methods such as aqueous two-phase method and ionic liquid extraction method have been developed. During past few decades, an ample variety of biological effects of capsaicin have been evaluated. Capsaicin can be used in biofilms and antifouling coatings due to its antimicrobial activity, allowing it has a promising application in food packaging, food preservation, marine environment and dental therapy. Capsaicin also play a crucial role in metabolic disorders, including weight loss, pressure lowing and insulin reduction effects. In addition, capsaicin was identified effective on preventing human cancers, such as lung cancer, stomach cancer, colon cancer and breast cancer by inducing apoptosis and inhibiting cell proliferation of tumor cells. Previous research also suggest the positive effects of capsaicin on pain relief and cognitive impairment. Capsaicin, the agonist of transient receptor potential vanilloid type 1 (TRPV1), could selectively activate TRPV1, inducing Ca²⁺ influx and related signaling pathways. Recently, gut microbiota was also involved in some diseases therapeutics, but its influence on the effects of capsaicin still need to be deeply studied. In this review, different extraction and purification methods of capsaicin, its biological activities and pharmacological effects were systematically summarized, as well as the possible mechanisms were also deeply discussed. This article will give an updated and better understanding of capsaicin-related biological effects and provide theoretical basis for its further research and applications in human health and manufacture development.

Decreased drug resistance of bladder cancer using phytochemicals treatment

The aim of the study is to investigate the ability of phytochemicals to overcome the multiple drug resistance (MDR) of bladder cancer. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to evaluate the cytotoxic sensitivity of T24-GCB cells, a GCB resistant cell line, to different phytochemicals, including capsaicin, quercetin, curcumin, and resveratrol, and their combination with gemcitabine. Western blot analysis was used to detect the expression of membranous ABCC2 and metabolic proteins, DCK, TK1, and TK2 in tumor cells. Animal models were used to confirm the treatment efficacy of phytochemicals in combination with gemcitabine to bladder cancer. The observed/expected ratio of cytotoxicity analysis revealed that capsaicin has synergistic effect with gemcitabine to T24-GCB cells in a dose-dependent pattern. Quercetin, curcumin, and resveratrol have additive effect with gemcitabine to T24-GCB cells. Capsaicin and quercetin alone and combination with gemcitabine decreased the expression of ABCC2 and DCK and TKs, in T24-GCB cells. On the contrary, resveratrol and curcumin alone and combination with gemcitabine increased the expression of ABCC2 but decreased cytoplasmic kinases simultaneously. In xenografted subcutaneous tumor model on nude mice, combination treatment of capsaicin and gemcitabine demonstrated the highest tumor suppression effect when compared to capsaicin or gemcitabine treatment alone. The MDR of bladder cancer is closely related to membranous ABCC2, cytoplasmic DCK, and TKs expression. Capsaicin owns the strongest synergistic cytotoxic effect of gemcitabine to T24-GCB cells. This combination regimen may provide as an adjunctive treatment for overcoming MDR in bladder cancer.

Capsaicin Acts Through Reducing P38 MAPK-Dependent Thymidylate Synthase Expression to Enhance 5-Fluorouracil-Induced Cytotoxicity in Human Lung Cancer Cells

Capsaicin, an ingredient of green and red bell peppers, shows anticancer activity in several malignant cell lines. Thymidylate synthase (TS) is a well-validated anticancer drug target in non-small cell lung cancer (NSCLC) cells. However, whether capsaicin and 5-fluorouracil (5-FU) induce synergistic cytotoxicity in NSCLC cells by regulating TS expression is unclear. This study investigated the cytotoxicity of capsaicin and 5-FU co-treatment on two hoursuman lung adenocarcinoma cell lines, H520 and H1703, and the underlying mechanisms. Capsaicin decreased TS expression in a p38 mitogen-activated protein kinase (MAPK) inactivation–dependent manner in H520 and H1703 cells. Enhancement of p38 MAPK activity by transfection with constitutive active mitogen-activated protein kinase kinase six vectors increased TS expression and cell survival. In addition, capsaicin and 5-FU co-treatment enhanced synergistic cytotoxicity and inhibited cell growth associated with TS downregulation and p38 MAPK inactivation in H520 and H1703 cells. Capsaicin and 5-FU co-treatment did not affect the cellular content of capsaicin. These results show that capsaicin may be combined with 5-FU to treat NSCLC.

Silencing of Long Non-coding RNA GAS5 Suppresses Neuron Cell Apoptosis and Nerve Injury in Ischemic Stroke Through Inhibiting DNMT3B-Dependent MAP4K4 Methylation

Ischemic stroke is associated with various physiological and pathological processes including neuronal apoptosis. Growth-arrest-specific transcript 5 (GAS5), a long non-coding RNA (lncRNA), has been recently reported to affect ischemic stroke-induced neuron apoptosis, while its mechanisms remain largely undefined. Through in silico analysis, GAS5 was predicted to interact with the promoter of MAP4K4. The aim of the present study was therefore to investigate the possible role of GAS5 in the progression of ischemic stroke via regulation of mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4) methylation. The expression of MAP4K4 was found to be lowly expressed in the clinical samples collected from 55 patients. MAP4K4 was suggested to be methylated in an in vitro model of oxygen-glucose deprivation (OGD)-treated mouse primary cortical neurons, while its overexpression could inhibit OGD-induced neuronal apoptosis. A series of dual-luciferase reporter, RIP, RNA pull-down, ChIP MSP, and BSP assays confirmed that GAS5 significantly induced MAP4K4 methylation and downregulated MAP4K4 expression through the recruitment of DNA methyltransferase 3B (DNMT3B). An in vivo ischemic stroke model was developed using middle cerebral artery occlusion (MCAO). Upregulation of GAS5 promoted OGD-induced neuronal apoptosis in the in vitro model and increased cerebral infarction size and neurological score in the in vivo model by reducing MAP4K4 expression. Collectively, the present study highlights that silencing GAS5 may inhibit neuronal apoptosis and improve neurological function in ischemic stroke by suppressing DNMT3B-mediated MAP4K4 methylation, which contributes to better understanding of the pathologies of ischemic stroke and development of novel therapeutic options for this disease.

TRPV1 Antagonist DWP05195 Induces ER Stress-Dependent Apoptosis through the ROS-p38-CHOP Pathway in Human Ovarian Cancer Cells

In addition to their analgesic activity, transient receptor potential vanilloid 1 (TRPV1) agonists and antagonists demonstrate profound anti-cancer activities in various human cancers. In the present study, we investigated the anti-cancer activity of a novel TRPV1 antagonist, DWP05195, and evaluated its molecular mechanism in human ovarian cancer cells. DWP05195 demonstrated potent growth inhibitory effects in all five ovarian cancer cell lines examined. DWP05195 induced apoptosis through the activation of caspase-3, -8, and -9. DWP05195 induced C/EBP homologous protein (CHOP) expression and endoplasmic reticulum (ER) stress. Sodium phenylbutyrate (4-PBA), an ER-stress inhibitor, and CHOP knockdown significantly suppressed DWP5195-induced cell death. DWP05195-enhanced CHOP expression stimulated intrinsic and extrinsic apoptotic pathways through the regulation of Bcl2-like11 (BIM), death receptor 4 (DR4), and DR5. DWP05195-induced cell death was associated with increased reactive oxygen species (ROS) levels and p38 pathway activation. Pre-treatment with the antioxidant N-acetyl-L-cysteine (NAC) significantly suppressed DWP05195-induced CHOP expression and p38 activation. Inhibition of NADPH oxidase (NOX) through p47phox knockdown abolished DWP05195-induced CHOP expression and cell death. Taken together, the findings indicate that DWP05195 induces ER stress-induced apoptosis via the ROS-p38-CHOP pathway in human ovarian cancer cells.

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.

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.

Repurposing of plant alkaloids for cancer therapy: Pharmacology and toxicology

Drug repurposing (or repositioning) is an emerging concept to use old drugs for new treatment indications. Phytochemicals isolated from medicinal plants have been largely neglected in this context, although their pharmacological activities have been well investigated in the past, and they may have considerable potentials for repositioning. A grand number of plant alkaloids inhibit syngeneic or xenograft tumor growth in vivo. Molecular modes of action in cancer cells include induction of cell cycle arrest, intrinsic and extrinsic apoptosis, autophagy, inhibition of angiogenesis and glycolysis, stress and anti-inflammatory responses, regulation of immune functions, cellular differentiation, and inhibition of invasion and metastasis. Numerous underlying signaling processes are affected by plant alkaloids. Furthermore, plant alkaloids suppress carcinogenesis, indicating chemopreventive properties. Some plant alkaloids reveal toxicities such as hepato-, nephro- or genotoxicity, which disqualifies them for repositioning purposes. Others even protect from hepatotoxicity or cardiotoxicity of xenobiotics and established anticancer drugs. The present survey of the published literature clearly demonstrates that plant alkaloids have the potential for repositioning in cancer therapy. Exploitation of the chemical diversity of natural alkaloids may enrich the candidate pool of compounds for cancer chemotherapy and -prevention. Their further preclinical and clinical development should follow the same stringent rules as for any other synthetic drug as well. Prospective randomized, placebo-controlled clinical phase I and II trials should be initiated to unravel the full potential of plant alkaloids for drug repositioning.

Capsaicin attenuates cell migration via SIRT1 targeting and inhibition to enhance cortactin and β-catenin acetylation in bladder cancer cells

We have studied the chemopreventive property of capsaicin, a major active component in chili pepper, and found that it exhibited apoptotic activity against various lines of cancer cells. Interestingly, accumulating data has revealed that, in addition to cytotoxicity, capsaicin also plays regulatory role on cell migration and invasion. However, its effect on cell migration is paradoxical and not completely understood. Here, we set out to elucidate the molecular events underlying capsaicin-inhibited cell migration in bladder cancer cells. Our results show that the capsaicin-reduced cell migration was associated with down-regulation of sirtuin 1 (SIRT1) deacetylase, possibly through proteasome-mediated protein degradation. More importantly, we employed a cellular thermal shift assay (CETSA) to demonstrate that there was a direct binding between capsaicin and SIRT1. The engagement with capsaicin and protein degradation diminished the deacetylase of SIRT1, which in turn, enhanced acetylation of cortactin and β-catenin to decrease MMP-2 and MMP-9 activation, resulting in cell migration impairment in bladder cancer cells.

Combination treatment of resveratrol and capsaicin radiosensitizes pancreatic tumor cells by unbalancing DNA repair response to radiotherapy towards cell death

Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest cancers because it is highly resistant to every available therapeutic strategy, in particular conventional chemotherapy or radiotherapy (RT). Sensitizing tumor cells to existing treatments remains a good option to obtain fast and applicable results. Considering that ionizing radiations induce radiolysis-derived reactive oxygen species (ROS), we hypothesized that ROS-inducing bioactive food components (BFCs) could exacerbate ROS-related cell damages, including DNA double stranded breaks (DSBs), leaving the cellular ROS scavenging systems overwhelmed, and precipitating tumor cell death. Combination of resveratrol and capsaicin radiosensitized radiosensitive tumor cells, but RT did not increase BFC combination toxicity in radioresistant tumor cells. BFC addition to RT increased ROS production and led to significant tumor volume reduction in xenografted mouse preclinical model. Strikingly, BFCs inhibited RT-induced DNA damage molecular response by strongly limiting the first steps of DSB repair, and by keeping cells in cell cycle, provoking exacerbated intrinsic apoptosis. This study positions BFCs as potent radiosensitizers when combined, and identifies an actionable molecular pathway by resveratrol and capsaicin combination.

Mechanism for Regulation of Melanoma Cell Death via Activation of Thermo-TRPV4 and TRPV2

Background

Thermo-TRPs (temperature-sensitive transient receptor potential channels) belong to the TRP (transient receptor potential) channel superfamily. Emerging evidence implied that thermo-TRPs have been involved in regulation of cell fate in certain tumors. However, their distribution profiles and roles in melanoma remain incompletely understood.

Methods

Western blot and digital PCR approaches were performed to identify the distribution profiles of six thermo-TRPs. MTT assessment was employed to detect cell viability. Flow cytometry was applied to test cell cycle and apoptosis. Calcium imaging was used to determine the function of channels. Five cell lines, including one normal human primary epidermal melanocytes and two human malignant melanoma (A375, G361) and two human metastatic melanoma (A2058, SK-MEL-3) cell lines, were chosen for this research.

Results

In the present study, six thermo-TRPs including TRPV1/2/3/4, TRPA1, and TRPM8 were examined in human primary melanocytes and melanoma cells. We found that TRPV2/4, TRPA1, and TRPM8 exhibited ectopic distribution both in melanocytes and melanoma cells. Moreover, activation of TRPV2 and TRPV4 could lead to the decline of cell viability for melanoma A2058 and A375 cells. Subsequently, activation of TRPV2 by 2-APB (IC₅₀ = 150 μM) induced cell necrosis in A2058 cells, while activation of TRPV4 by GSK1016790A (IC₅₀ = 10 nM) enhanced apoptosis of A375 cells. Furthermore, TRPV4 mediated cell apoptosis of melanoma via phosphorylation of AKT and was involved in calcium regulation.

Conclusion

Overall, our studies revealed that TRPV4 and TRPV2 mediated melanoma cell death via channel activation and characterized the mechanism of functional TRPV4 ion channel in regulating AKT pathway driven antitumor process. Thus, they may serve as potential biomarkers for the prognosis and are targeted for the therapeutic use in human melanoma.

Naringenin suppresses growth of human placental choriocarcinoma via reactive oxygen species-mediated P38 and JNK MAPK pathways

BACKGROUND

Human placental choriocarcinoma is a gestational trophoblastic tumor with high rates of metastasis and reoccurrence. However, some patients with choriocarcinoma are chemoresistance to conventional chemotherapeutic agents.

HYPOTHESIS

Naringenin increases apoptosis in human placental choriocarcinoma cells.

METHODS

We investigated the effects of naringenin on proliferation and migration of JAR and JEG3 cells, and performed TUNEL and Annexin V/PI staining assays to examine apoptotic effects of naringenin on both cells. In addition, we studied the loss of mitochondrial membrane potential (MMP) and the production of mitochondrial reactive oxygen species (ROS) to determine the specific reason for apoptosis of choriocarcinoma cells being mediated via mitochondria. Consistent with the induction of production of ROS by naringenin in both choriocarcinoma cell lines, we investigated lipid peroxidation and glutathione levels in both JAR and JEG3 cells since both are affected by ROS. We next determined dose-dependent effects of naringenin and its pharmacological inhibitors on signal transduction pathways in JAR and JEG3 cells by western blot analyses.

RESULTS

Naringenin reduced viability and migratory functions of both cell lines, and increased mitochondria related apoptosis induced by ROS and lipid peroxidation, decreased glutathione and decreased mitochondrial membrane potential MMP in a dose-dependent manner. We also determined naringenin activated phosphorylation of ERK1/2, P38, JNK and P70S6K in JAR and JEG3 cells in a dose-response manner. Although naringenin induced phosphorylation of AKT proteins in JAR cells, it suppressed phosphorylation of the protein in JEG3 cells. In addition, we confirmed the mechanism of naringenin-induced cell signaling by using a combination of naringenin and pharmacological inhibitors of the PI3K and MAPK pathways, as well as a ROS inhibitor in JAR and JEG3 cell lines.

CONCLUSIONS

Collectively, results of this study indicate that naringenin is a potential therapeutic molecule with anti-cancer effects on choriocarcinoma cells by inducing generation of ROS and activation of the MAPK pathways.

Hepatoprotective effect of quercetin via TRAF6/JNK pathway in acute hepatitis

Quercetin, as a member of the flavonoids family, has many beneficial properties. The aim of our study was to evaluate the protective effect of quercetin in ConA-induced hepatitis in mice, and to clarify its mechanism of action. Hepatitis was induced by using ConA (25 mg/kg), and quercetin was administered intragastrically at the dose of 100 mg/kg or 200 mg/kg for 5 days before ConA injection. The serum levels of liver enzymes, inflammatory cytokines and other marker proteins were determined at 2 h, 8 h and 24 h after ConA injection. Following ConA injection, serum levels of liver enzymes and inflammatory cytokines were significantly increased. Quercetin ameliorated liver damage and histopathological changes, and suppressed the release of inflammatory cytokines. The expression of Bax, Bcl-2, Beclin-1, LC3, P62 and caspase 9 were markedly affected by quercetin pretreatment. The expression of TRAF6 and p-JNK were decreased in the quercetin groups. Quercetin attenuated apoptosis and autophagy in ConA-induced autoimmune hepatitis by inhibiting TRAF6/JNK pathway.

3,3'‑Diindolylmethane attenuates cardiomyocyte hypoxia by modulating autophagy in H9c2 cells

Autophagy is activated in the ischemic heart and is a process that is essential for survival, differentiation, development and homeostasis. 3,3'‑Diindolylmethane (DIM) is a natural product of the acid‑catalyzed condensation of indole‑3‑carbinol in cruciferous vegetables. Numerous studies have suggested that DIM has various pharmacological effects, including antioxidant, antitumor, anti‑angiogenic and anti‑apoptotic properties. However, the function of DIM on hypoxia‑induced cardiac injury remains to be elucidated. In the present study, H9c2 cells were pretreated with DIM (1, 5 and 10 µM) for 12 h and exposed to hypoxia for 12 h. It was demonstrated that DIM markedly attenuated the increased transcription of interleukin (IL)‑1β, IL‑6 and tumor necrosis factor‑α induced by hypoxia. In addition, the transcription of autophagy associated genes increased in the DIM pretreated group, compared with the hypoxia group. DIM additionally attenuated the increased apoptosis, as determined by terminal deoxynucleotidyl transferase dUTP nick end labeling staining, and regulated the relative protein expression level of B cell lymphoma (Bcl) 2 associated X protein, Bcl‑xL and cleaved caspase 3. Furthermore, the phosphorylation of the 5' AMP‑activated protein kinase a (AMPKa) was activated and the phosphorylation of c‑Jun N‑terminal kinase (JNK) was inhibited. The effect of DIM on hypoxia‑induced apoptosis was abolished following pretreatment with JNK activator (anisomycin, 40 ng/ml). The effect of DIM on autophagy was reversed following pretreatment with AMPKa inhibitor (CpC, 20 µM) following stimulation with hypoxia. The results demonstrated that DIM prevented hypoxia‑induced inflammation and apoptosis and activated cardiomyocyte autophagy, which may be mediated by activation of AMPKa and inhibition of JNK pathways.

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.

Resveratrol and capsaicin used together as food complements reduce tumor growth and rescue full efficiency of low dose gemcitabine in a pancreatic cancer model

Pancreatic adenocarcinoma, highly resistant to all current anti-cancer treatments, necessitates new approaches promoting cell death. We hypothesized that combined actions of several Bioactive Food Components (BFCs) might provide specific lethal effect towards tumor cells, sparing healthy cells. Human tumor pancreatic cell lines were tested in vitro for sensitivity to resveratrol, capsaicin, piceatannol, and sulforaphane cytotoxic effects. Combination of two or three components showed striking synergetic effect with gemcitabine in vitro. Each BFC used alone did not affect pancreatic tumor growth in a preclinical in vivo model, whereas couples of BFCs had anti-tumor activity. In addition, tumor toxicity was similar using gemcitabine alone or a combination of BFCs and two thirds of gemcitabine dose. Moreover, BFCs enhanced fibrotic response as compared to gemcitabine treatment alone. Reactive oxygen species (ROS) and apoptosis increases were observed, while cell cycle was very mildly affected. This study raises the possibility to use BFCs as beneficial food complements in the therapy of pancreatic adenocarcinoma, especially for patients unable to receive full doses of chemotherapy.

Targeting calcium signaling in cancer therapy

The intracellular calcium ions (Ca2+) act as second messenger to regulate gene transcription, cell proliferation, migration and death. Accumulating evidences have demonstrated that intracellular Ca2+ homeostasis is altered in cancer cells and the alteration is involved in tumor initiation, angiogenesis, progression and metastasis. Targeting derailed Ca2+ signaling for cancer therapy has become an emerging research area. This review summarizes some important Ca2+ channels, transporters and Ca2+-ATPases, which have been reported to be altered in human cancer patients. It discusses the current research effort toward evaluation of the blockers, inhibitors or regulators for Ca2+ channels/transporters or Ca2+-ATPase pumps as anti-cancer drugs. This review is also aimed to stimulate interest in, and support for research into the understanding of cellular mechanisms underlying the regulation of Ca2+ signaling in different cancer cells, and to search for novel therapies to cure these malignancies by targeting Ca2+ channels or transporters.