Diallyl Trisulfide Inhibits Growth of NCI-H460 in Vitro and in Vivo, and Ameliorates Cisplatin-Induced Oxidative Injury in the Treatment of Lung Carcinoma in Xenograft Mice

Diallyl trisulfide induces pyroptosis and impairs lung CSC-like properties by activating the ROS/Caspase 1 signaling pathway

Lung cancer stem cells (CSCs) drive continuous cancer growth and metastatic dissemination; thus, there is an urgent requirement to acquire effective therapeutic strategies for targeting lung CSCs. Diallyl trisulfide (DATS), a garlic organosulfide, possesses suppressive potential in lung cancer; however, its underlying mechanism is still unclear. In this study, we identified DATS as a pyroptosis inducer in lung cancer cells. DATS-treated A549 and H460 cells exhibited pyroptotic cell death, with characteristic large bubbles appearing on their plasma membrane and LDH release. DATS induced cell death, arrested the cell cycle at the G2/M phase, and inhibited colony formation in lung cancer cells. Meanwhile, we found that DATS significantly suppressed the malignant features by impairing lung CSC-like properties, including sphere formation ability, CD133 positive cell number, and lung CSCs marker expression. Mechanistically, DATS induced cell pyroptosis via increasing the expression of NLRP3, ASC, Pro Caspase 1, Cleaved Caspase 1, GSDMD, GSDMD-N, and IL-1β. The verification experiments showed that the effects of DATS on pyroptosis and lung CSC-like properties were weakened after Caspase 1 inhibitor VX-765 treatment, indicating that DATS activated NLRP3 inflammasome-mediated pyroptosis by targeting Caspase 1 in lung cancer cells. Moreover, DATS increased ROS overproduction and mitochondrial dysfunction, which contributed to DATS-induced pyroptosis of lung cancer cells. NAC treatment reversed the effects of DATS on pyroptosis and CSC-like properties. In vivo experiment further confirmed that DATS restrained tumor growth. Together, our results suggest that DATS promotes pyroptosis and impairs lung CSC-like properties by activating ROS/Caspase 1 signaling pathway, thereby retarding lung cancer progression.

The Anticancer Effects of the Garlic Organosulfide Diallyl Trisulfide through the Attenuation of B[a]P-Induced Oxidative Stress, AhR Expression, and DNA Damage in Human Premalignant Breast Epithelial (MCF-10AT1) Cells

Benzo[a]pyrene (B[a]P) is the most characterized polycyclic aromatic hydrocarbon associated with breast cancer. Our lab previously reported that the organosulfur compound (OSC), diallyl trisulfide (DATS), chemoprevention mechanism works through the induction of cell cycle arrest and a reduction in oxidative stress and DNA damage in normal breast epithelial cells. We hypothesize that DATS will inhibit B[a]P-induced cancer initiation in premalignant breast epithelial (MCF-10AT1) cells. In this study, we evaluated the ability of DATS to attenuate B[a]P-induced neoplastic transformation in MCF-10AT1 cells by measuring biological endpoints such as proliferation, clonogenicity, reactive oxygen species (ROS) formation, and 8-hydroxy-2-deoxyguanosine (8-OHdG) DNA damage levels, as well as DNA repair and antioxidant proteins. The results indicate that B[a]P induced proliferation, clonogenic formation, ROS formation, and 8-OHdG levels, as well as increasing AhR, ARNT/HIF-1β, and CYP1A1 protein expression compared with the control in MCF-10AT1 cells. B[a]P/DATS's co-treatment (CoTx) inhibited cell proliferation, clonogenic formation, ROS formation, AhR protein expression, and 8-OHdG levels compared with B[a]P alone and attenuated all the above-mentioned B[a]P-induced changes in protein expression, causing a chemopreventive effect. This study demonstrates, for the first time, that DATS prevents premalignant breast cells from undergoing B[a]P-induced neoplastic transformation, thus providing more evidence for its chemopreventive effects in breast cancer.

Diallyl trisulfide inhibits 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced lung cancer via modulating gut microbiota and the PPARγ/NF-κB pathway

Smoking is the primary risk factor for developing lung cancer. Chemoprevention could be a promising strategy to reduce the incidence and mortality rates of lung cancer. Recently, we reported that A/J mice exposed to tobacco smoke carcinogens displayed the reshaping of gut microbiota. Additionally, garlic oil was found to effectively inhibit the carcinogenic effects of tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in lung tumorigenesis. Diallyl trisulfide (DATS), which is the predominant compound in garlic oil, exhibits various biological activities. To further explore the chemopreventive action and potential mechanism of DATS on lung tumorigenesis, we established a lung adenocarcinoma model in A/J mice stimulated by NNK. Subsequently, we employed multi-omics combined molecular biology technologies to clarify the mechanism. The results indicated that DATS significantly decreased the number of lung tumors in NNK induced A/J mice. Interestingly, we discovered that DATS could modulate gut microbiota, particularly increasing the abundance of F. rodentium, which has inhibitory effects on tumor growth. Mechanistically, DATS could activate the PPARγ pathway, leading to the negative regulation of the NF-κB signaling pathway and subsequent suppression of NF-κB-mediated inflammatory factors. Collectively, these findings provide support for DATS as a potential novel chemopreventive agent for tobacco carcinogen-induced lung cancer.

Caffeic acid phenethyl ester surmounts acquired resistance of AZD9291 in non-small cell lung cancer cells

Epithelial growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are the first-line therapy for EGFR mutated non-small cell lung cancer (NSCLC); however, resistance rapidly develops. The objective of this study was therefore to establish and characterize a gefitinib resistant NSCLC line (HCC827GR) and evaluate the therapeutic effects of natural products in combination with third-generation EGFR-TKI, AZD9291. The IC50 of gefitinib and AZD9291 in HCC827GR were significantly higher than those of HCC827 (p < 0.05). Furthermore, anchorage-independent colony assay indicated that HCC827GR cells were more aggressive than their predecessors. This was reflected by the gene/protein expression changes observed in HCC827GR versus HCC827 profiled by cancer drug resistance real-time polymerase chain reaction (RT-PCR) array and Western blot. Three natural products were screened and caffeic acid phenethyl ester (CAPE) exhibited the most significant combinative cytotoxic effect with AZD9291. Specifically, flow cytometry revealed that AZD9291 + CAPE considerably increased the fraction of cell in pre-G1 of the cell cycle and caspase-Glo3/7 assay showed a dramatic increase in apoptosis when compared to AZD9291 alone. Furthermore, Western blot showed significant downregulation of p-EGFR/p-AKT in HCC827GR cells treated with AZD9291 + CAPE as compared to AZD9291. Moreover, it is evident that AZD9291 + CAPE specifically resulted in a marked reduction in the protein expressions of the cell-proliferation-related genes p21, cyclin D1, and survivin. Finally, refined RT-PCR/Western blot data indicated that AZD9291 + CAPE may at least partially exert its synergistic effects via the PLK2 pathway. Together, these results suggest that CAPE is a clinically relevant compound to aid AZD9291 in treating EGFR-TKI resistant cells through modulating critical genes/proteins involved in cancer resistance/therapy.

The Role of Hydrogen Sulfide in the Development and Progression of Lung Cancer

Lung cancer is one of the 10 most common cancers in the world, which seriously affects the normal life and health of patients. According to the investigation report, the 3-year survival rate of patients with lung cancer is less than 20%. Heredity, the environment, and long-term smoking or secondhand smoke greatly promote the development and progress of the disease. The mechanisms of action of the occurrence and development of lung cancer have not been fully clarified. As a new type of gas signal molecule, hydrogen sulfide (H₂S) has received great attention for its physiological and pathological roles in mammalian cells. It has been found that H₂S is widely involved in the regulation of the respiratory system and digestive system, and plays an important role in the occurrence and development of lung cancer. H₂S has the characteristics of dissolving in water and passing through the cell membrane, and is widely expressed in body tissues, which determines the possibility of its participation in the occurrence of lung cancer. Both endogenous and exogenous H₂S may be involved in the inhibition of lung cancer cells by regulating mitochondrial energy metabolism, mitochondrial DNA integrity, and phosphoinositide 3-kinase/protein kinase B co-pathway hypoxia-inducible factor-1α (HIF-1α). This article reviews and discusses the molecular mechanism of H₂S in the development of lung cancer, and provides novel insights for the prevention and targeted therapy of lung cancer.

Involvement of adaptor protein, phosphotyrosine interacting with PH domain and leucine zipper 1 in diallyl trisulfide-induced cytotoxicity in hepatocellular carcinoma cells

It has been demonstrated that APPL1 (adaptor protein, phosphotyrosine interacting with PH domain and leucine zipper 1) is involved in the regulation of several growth-related signaling pathways and thus closely associated with the development and progression of some cancers. Diallyl trisulfide (DAT), a garlic-derived bioactive compound, exerts selective cytotoxicity to various human cancer cells through interfering with pro-survival signaling pathways. However, whether and how DAT affects survival of human hepatocellular carcinoma (HCC) cells remain unclear. Herein, we tested the hypothesis of the involvement of APPL1 in DAT-induced cytotoxicity in HCC HepG2 cells. We found that Lys 63 (K63)-linked polyubiquitination of APPL1 was significantly decreased whereas phosphorylation of APPL1 at serine residues remained unchanged in DAT-treated HepG2 cells. Compared with wild-type APPL1, overexpression of APPL1 K63R mutant dramatically increased cell apoptosis and mitigated cell survival, along with a reduction of phosphorylation of STAT3, Akt, and Erk1/2. In addition, DAT administration markedly reduced protein levels of intracellular TNF receptor-associated factor 6 (TRAF6). Genetic inhibition of TRAF6 decreased K63-linked polyubiquitination of APPL1. Moreover, the cytotoxicity impacts of DAT on HepG2 cells were greatly attenuated by overexpression of wild-type APPL1. Taken together, these results suggest that APPL1 polyubiquitination probably mediates the inhibitory effects of DAT on survival of HepG2 cells by modulating STAT3, Akt, and Erk1/2 pathways.

Health-promoting foods and food crops of West-Africa origin: The bioactive compounds and immunomodulating potential

The rural communities of the sub-Sahara regions in Africa are rich in diverse indigenous culinary knowledge and foods, food crops, and condiments such as roots/tubers, cereal, legumes/pulses, locust beans, and green leafy vegetables. These food crops are rich in micronutrients and phytochemicals, which have the potentials to address hidden hunger as well as promote health when consumed. Some examples of these are fermented foods such as ogi and plants such as Vernonia amygdalina (bitter leaf), Zingiber officinales (garlic), Hibiscus sabdariffa (Roselle), and condiments. Food crops from West Africa contain numerous bioactive substances such as saponins, alkaloids, tannins, phenolics, flavonoids, and monoterpenoid chemicals among others. These bioresources have proven biological and pharmacological activities due to diverse mechanisms of action such as immunomodulatory, anti-inflammatory, antipyretic, and antioxidant activities which made them suitable as candidates for nutraceuticals and pharma foods. This review seeks to explore the different processes such as fermentation applied during food preparation and food crops of West-African origin with health-promoting benefits. The different bioactive compounds present in such food or food crops are discussed extensively as well as the diverse application, especially regarding respiratory diseases. PRACTICAL APPLICATIONS: The plants and herbs summarized here are more easily accessible and affordable by therapists and others having a passion for promising medicinal properties of African-origin plants.The mechanisms and unique metabolic potentials of African food crops discussed in this article will promote their applicability as a template molecule for novel drug discoveries in treatment strategies for emerging diseases. This compilation of antiviral plants will help clinicians and researchers bring new preventive strategies in combating COVID-19 like viral diseases, ultimately saving millions of affected people.

Oleanolic acid induces HCT116 colon cancer cell death through the p38/FOXO3a/Sirt6 pathway

Oleanolic acid (OA) is a natural compound that possesses numerous beneficial health effects, including anticancer activity. The current study aimed to investigate the role of forkhead box O3a (FOXO3a) in autophagy/mitophagy by OA in HCT116 cell line. OA dose-dependently reduced viability of HCT116 cells, with IC₅₀ = 29.8 μΜ. The expression of cleaved caspase-3 and poly (ADP-ribose) polymerase 1 increased after OA treatment, suggesting induction of apoptosis. Concurrently, OA induced autophagy, evidenced by increased expression of Beclin-1, autophagy-related protein 5 and microtubule-associated protein1A/1B-light chain 3 beta (LC3B), which played a prosurvival role. The induction of mitophagy was suggested by increased expression of p62 and PTEN-induced kinase 1 and reduced expression of translocase of outer mitochondrial membrane 20, which colocalized with LC3B. OA also induced nuclear accumulation of forkhead box O3a (FOXO3a). The cytotoxic activity of OA coincided with upregulation of p38. Inhibition of p38 led to increase in FOXO3a and NAD⁺-dependent deacetylase sirtuin 6 expression. In vivo, OA inhibited tumor growth in colon cancer xenograft mice. Our results suggest concomitant induction of apoptosis and prosurvival mitophagy by OA in colon cancer via p38/FOXO3a/Sirt6 signaling. Additionally, our data demonstrate that OA can chemosensitize colon cancer cells to 5-fluorouracil (5-FU).

Lipid-Based Nanoparticle Formulation of Diallyl Trisulfide Chemosensitizes the Growth Inhibitory Activity of Doxorubicin in Colorectal Cancer Model: A Novel In Vitro, In Vivo and In Silico Analysis

Garlic’s main bioactive organosulfur component, diallyl trisulfide (DATS), has been widely investigated in cancer models. However, DATS is not suitable for clinical use due to its low solubility. The current study seeks to improve DATS bioavailability and assess its chemopreventive and chemosensitizing properties in an AOM-induced colorectal cancer model. The polyethylene glycol coated Distearoylphosphatidylcholine/Cholesterol (DSPC/Chol) comprising DATS-loaded DATSL and doxorubicin (DOXO)-encapsulated DOXL liposomes was prepared and characterized. The changes in the sensitivity of DATS and DOXO by DATSL and DOXL were evaluated in RKO and HT-29 colon cancer cells. The synergistic effect of DATSL and DOXL was studied by cell proliferation assay in the combinations of IC₁₀, IC₂₅, and IC₃₅ of DATSL with the IC₁₀ of DOXL. AOM, DATSL, and DOXL were administered to different groups of mice for a period of 21 weeks. The data exhibited ~93% and ~46% entrapment efficiency of DATSL and DOXL, respectively. The size of sham liposomes was 110.5 nm, whereas DATSL and DOXL were 135.5 nm and 169 nm, respectively. DATSL and DOXL exhibited significant sensitivity in the cell proliferation experiment, lowering their IC₅₀ doses by more than 8- and 14-fold, respectively. However, the DATSL IC₁₀, IC₂₅, and IC₃₅ showed escalating chemosensitivity, and treated the cells in combination with DOXL IC₁₀. Analysis of histopathological, cancer marker enzymes, and antioxidant enzymes revealed that the high dose of DATSL pretreatment and DOXL chemotherapy is highly effective in inhibiting AOM-induced colon cancer promotion. The combination of DATSL and DOXL indicated promise as a colorectal cancer treatment in this study. Intermolecular interactions of DATS and DOXO against numerous cancer targets by molecular docking indicated MMP-9 as the most favourable target for DATS exhibiting binding energy of −4.6 kcal/mol. So far, this is the first research to demonstrate the chemopreventive as well as chemosensitizing potential of DATSL in an animal model of colorectal cancer.

Therapeutic potential of Scutellaria baicalensis Georgi in lung cancer therapy

BACKGROUND

Globally, lung cancer is the leading cause of cancer associated mortalities. The current conventional chemotherapy remains the preferred treatment option for lung cancer, as surgical resection plays little role in the treatment of over 75% of lung cancer patients. Therefore, there is a need to develop novel potential therapeutic drugs or adjuvants with a high efficiency and safety against lung cancer. Scutellaria baicalensis Georgi, a common Chinese medicinal herb that has been in use for more than 2000 years, has recently been shown to possess significant activities against lung cancer. However, current research progress on pharmacological effects and relevant molecular mechanisms of S. baicalensis in lung cancer therapy have not been systematically summarized.

PURPOSE

This review aimed at elucidating on the anti-lung cancer mechanisms and antitumor efficacies of S. baicalensis as well as its active ingredients, and providing a valuable reference for further investigation in this field.

METHODS

We used "Scutellaria baicalensis" or the name of the compound in S. baicalensis, in combination with "lung cancer" as key words to systematically search for relevant literature from the Web of Science and PubMed databases. Publications that investigated molecular mechanisms were the only ones selected for analysis. The PRISMA guidelines were followed.

RESULTS

Fifty-four publications met the inclusion criteria for this study. Five anti-lung cancer mechanisms of S. baicalensis and its constituent components are discussed. These mechanisms include apoptosis induction, cell-cycle arrest, suppression of proliferation, blockade of invasion and metastasis, and overcoming drug-resistance. These compounds exhibited high antitumor efficacies and safety against lung cancer xenografts.

CONCLUSION

Studies should aim at elucidating on the anti-cancer mechanisms of S. baicalensis to achieve the ultimate goal of lung cancer therapy.

Diallyl disulfide and diallyl trisulfide in garlic as novel therapeutic agents to overcome drug resistance in breast cancer

Breast cancer is one of the leading causes of cancer-related deaths in women worldwide. It is a cancer that originates from the mammary ducts and involves mutations in multiple genes. Recently, the treatment of breast cancer has become increasingly challenging owing to the increase in tumor heterogeneity and aggressiveness, which gives rise to therapeutic resistance. Epidemiological, population-based, and hospital-based case-control studies have demonstrated an association between high intake of certain Allium vegetables and a reduced risk in the development of breast cancer. Diallyl disulfide (DADS) and diallyl trisulfide (DATS) are the main allyl sulfur compounds present in garlic, and are known to exhibit anticancer activity as they interfere with breast cancer cell proliferation, tumor metastasis, and angiogenesis. The present review highlights multidrug resistance mechanisms and their signaling pathways in breast cancer. This review discusses the potential anticancer activities of DADS and DATS, with emphasis on drug resistance in triple-negative breast cancer (TNBC). Understanding the anticancer activities of DADS and DATS provides insights into their potential in targeting drug resistance mechanisms of TNBC, especially in clinical studies.

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The review describes the causes of drug resistance in TNBC.

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The effects of DADS and DATS on drug resistance mechanisms in TNBC are presented.

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The impacts of DADS and DATS on metastasis of TNBC are discussed.

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Antitumor immune activities of DADS and DATS against TNBC are illustrated.

Diallyl trisulfide potentiates chemotherapeutic efficacy of doxorubicin in experimentally induced mammary carcinoma: Role of Notch signaling

The prevalence of breast cancer is remarkably increasing worldwide. Therefore, introduction of new approaches along with improvement of the existing ones in cancer treatment field is of great demand. The present study was designated to investigate the anti-proliferative role of Diallyl trisulfide (DATS) alone or in combination with Doxorubicin (Doxo) in Ehrlich solid carcinoma (ESC)-bearing mice. ESC was induced in female albino mice as an experimental model for breast cancer. The anti-tumorigenic effect of DATS was mediated by suppression of Notch signaling proteins (Notch 1, JAG 1 and HES 1), attenuation of tumor inflammation (NFκB, TNF-α, IL-6, IL-1β) and proliferation (cyclin D1, Ki67) and enhancement of apoptosis (caspase 3, p53). DATS and Doxo mono-treatments displayed opposing effect regarding expression of Notch signaling proteins and cyclin D1 gene expression. However, DATS and Doxo co-treatment markedly decreased tumor volume and weight, increased animals' survival rate, and attenuated Doxo-induced tumor inflammation. In parallel, microscopic investigation displayed that ESC tumor tissues from animals treated with DATS and/or DOX showed shrinkage of tumor lesions and wider zones of apoptosis. In conclusion, DATS acts via multiple molecular targets to elicit anti-proliferative activity. Combination of DATS with Doxo -which exhibit different mechanisms of action- might be a potential novel strategy to augment Doxo-antitumor effect.

S-Allylcysteine as an Inhibitor of Benzo(a)pyrene-Induced Precancerous Carcinogenesis in Human Lung Cells via Inhibiting Activation of Nuclear Factor-Kappa B

Oil-soluble organosulfur compounds in garlic are known for the anticancer effect. However, there are limited experimental studies to describe the effect of S-allylcysteine (SAC), a main water-soluble derivative of garlic, in carcinogenesis. This study investigates the prevention function of SAC on carcinogen benzo(a)pyrene (B(a)P)-induced precancerous activity in human lung cells (A549). A549 cells were either pretreated (PreTM) or concurrently treated (CoTM) with 1 μM B(a)P and either 10 or 50 μM SAC. The 50 μM CoTM group inhibited B(a)P-induced cell proliferation by approximately 100%. The 50 μM SAC CoTM and PreTM inhibited the B(a)P-induced G2/M phase shift by 119% and 100%, respectively. Furthermore, the SAC PreTM exhibited the potential to reduce the generation of reactive oxygen species (ROS) in cells relative to the B(a)P group by approximately 100%. The CoTM and PreTM elevated superoxide dismutase (SOD) by at least 70% compared with B(a)P group. In this study, we demonstrated that the mechanisms involved in the inhibitory role of SAC in B(a)P-induced carcinogenesis, including suppression of cell proliferation and DNA damage, cell cycle regulation, attenuation of ROS formation, increase of SOD activity, and inhibition of nuclear factor-kappa B (NF-κB) activity, which indicated that SAC is potentially a novel therapeutic candidate for the prevention and treatment of B(a)P-induced human lung cancer.

Diallyl trisulfide induces G2/M cell-cycle arrest and apoptosis in anaplastic thyroid carcinoma 8505C cells

Anaplastic thyroid cancer (ATC) is the most aggressive thyroid cancer. Current approaches including surgery, chemotherapy and therapeutic drugs provide limited benefits for ATC patients. Diallyl trisulfide (DATS) has been documented as a promising anti-cancer agent for various carcinomas. However, its role in ATC tumorigenesis remained unclear. Our results showed that DATS treatment at 12.5, 25 and 50 μM decreased the viability of 8505C cells both in a time- and dose-dependent manner. The phosphorylation of H2A.X, which is a DNA damage marker, was induced by DATS both in a dose- and time-dependent manner. Moreover, DATS mediated the DNA damage through the phosphorylation of ATM but not ATR. DATS also induced G2/M cell-cycle arrest followed by the translocation of Cdc25C from the nucleus to the cytoplasm. Further results showed that DATS induced mitochondrial apoptosis in 8505C cells, evidenced by Hoechst/PI double staining, PI-Annexin V assay and western blot. Taken altogether, our findings demonstrated that DATS induced G2/M cell-cycle arrest and mitochondrial apoptosis by triggering DNA damage in ATC 8505C cells, which shed light on a novel therapeutic approach for ATC treatment.

Diplatin, a Novel and Low-Toxicity Anti-Lung Cancer Platinum Complex, Activation of Cell Death in Tumors via a ROS/JNK/p53-Dependent Pathway, and a Low Rate of Acquired Treatment Resistance

Background: Platinum-based drugs prevail as the main treatment of lung cancer; this is caused by their relative effectiveness despite known side effects, such as neurotoxicity. The risk reward of the treatment and side effects is confronted when dosage is considered and when resistance to treatment develops. Development of new compounds that improve effectiveness and safety profiles addresses this ongoing need in clinical practice.

Objectives: The novel water-soluble platinum complex, diplatin, was synthesized, and its antitumor potency and toxicology profile were evaluated in murine xenograft tumor models and in lung cancer cell lines.

Methods: The effects of diplatin, cisplatin (DDP), and carboplatin (CBP) on the viability of nine lung tumor cell lines and one normal human lung epithelial cell line were evaluated using the MTT assay. Therapeutic index was calculated as LD₅₀/ED₅₀ to identify and compare the ideal therapeutic windows of the above compounds. Diplatin’s antitumor effects were assessed in lung xenograft tumors of nude mice; molecular mechanisms of therapeutic effects were identified.

Results: Diplatin had desirable IC₅₀ compared to CBP in a variety of cultured tumor cells, notably lung tumor cells. In the mouse xenograft lung tumor, diplatin led to a substantially improved therapeutic index when compared to the effects of DDP and CBP. Importantly, diplatin inhibited the growth of DDP-resistant lung tumor cells. Diplatin’s mode of action was characterized to be through cell cycle arrest in the G2/M phase and induction of lung tumor apoptosis via ROS/JNK/p53-mediated pathways.

Conclusion: Diplatin was observed to have antitumor effects in mice with both greater potency and safety compared with DDP and CBP. These observations indicate that diplatin is promising as a potential treatment in future clinical applications.

Effects of sulfide and polysulfides transmitted by direct or signal transduction-mediated activation of TRPA1 channels

Hydrogen sulfide (H₂S) is a gaseous mediator in various physiological and pathological processes, including neuroimmune modulation, metabolic pathways, cardiovascular system, tumour growth, inflammation and pain. Now the hydrogen polysulfides (H₂S_n) have been recognised as signalling molecules modulating ion channels, transcription factors and protein kinases. Transient receptor potential (TRP) cation channels can be activated by mechanical, thermal or chemical triggers. Here, we review the current literature regarding the biological actions of sulfide and polysulfide compounds mediated by TRP channels with special emphasis on the role of TRPA1, best known as ion channels in nociceptors. However, the non‐neuronal TRPA1 channels should also be considered to play regulatory roles. Although sulfide and polysulfide effects in different pathological circumstances and TRPA1‐mediated processes have been investigated intensively, our review attempts to present the first comprehensive overview of the potential crosstalk between TRPA1 channels and sulfide‐activated signalling pathways.

Linked Articles

This article is part of a themed section on Chemical Biology of Reactive Sulfur Species. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.4/issuetoc

Wnt/β-catenin modulates chronic tobacco smoke exposure-induced acquisition of pulmonary cancer stem cell properties and diallyl trisulfide intervention

Lung cancer is the leading cause of cancer-related death worldwide; tobacco smoke (TS) constitutes the main causes of lung cancer. Acquisition of cancer stem cells (CSCs)-like properties is the essential progression for the initiation of lung cancer. However, the mechanisms for tobacco smoke-induced lung carcinogenesis remain elusive. In the present study, we demonstrated that long-term exposure of human bronchial epithelial (HBE) cells to TS resulted in malignant transformation and acquisition of CSC-like properties. Moreover, Wnt/β-catenin pathway was involved in acquisition of the CSC-like phenotype during neoplastic transformation of HBE cells induced by TS. Downregulation of β-catenin reduced the tumorsphere and decreased the protein expression of lung CSCs markers in TS-transformated HBE sphere-forming cells. Furthermore, Diallyl trisulfide (DATS) inhibited the CSCs activity of TS-transformed HBE cells, as well as Wnt/β-catenin suppression. Activation of Wnt/β-catenin diminished the inhibitory effects of DATS on TS-induced stemness of HBE cells. Together, the present investigation elucidates the modulation of Wnt/β-catenin in chronic TS exposure-triggered pulmonary acquisition of CSCs properties and DATS intervention, which may provide new insights into the interventional strategies against lung CSCs.

Methylallyl sulfone attenuates inflammation, oxidative stress and lung injury induced by cigarette smoke extract in mice and RAW264.7 cells

In this study, we revealed that methylallyl sulfone (AMSO2), the metabolite of active organosulfur compounds, had anti-inflammatory and antioxidant effect in a cigarette smoke extract (CSE)-induced lung injury model. Firstly, histological analysis showed that the CSE group exhibited lung injury compared with the control, which was alleviated by AMSO2. Secondly, we estimated its anti-inflammatory capacity. The results indicated that pretreatment with AMSO2 significantly decreased CSE-elevated tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in serum. Thirdly, AMSO2 also showed antioxidant properties through enhancing activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) as well as reducing the level of malondialdehyde (MDA) and myeloperoxidase (MPO). Finally, we elucidated that AMSO2 alleviated inflammation and oxidative stress probably via suppressing ERK/p38 MAPK and inhibiting NF-κB expressions. In conclusion, we proposed that AMSO2 protected against the development of CSE-induced lung injury by reducing inflammatory cytokine levels and augmenting antioxidant activity via ERK/p38 MAPK and NF-κB pathways.

Diallyl trisulfide induces apoptosis and mitotic arrest in AGS human gastric carcinoma cells through reactive oxygen species-mediated activation of AMP-activated protein kinase

Diallyl trisulfide (DATS), one of the principal constituents of garlic oil, is a kind of organosulfur compound with high anti-cancer activity. Although inhibition of cancer cell proliferation by DATS is known to be associated with the induction of apoptosis and cell cycle arrest related to reactive oxygen species (ROS) production, it is still necessary to study the detailed mechanisms. In this study, we investigated the role of ROS on the activation of AMP-activated protein kinase (AMPK) in DATS-induced apoptosis and cell cycle arrest in AGS human gastric carcinoma cells. The results of the present study indicate that DATS inhibited proliferation of AGS cells by promoting apoptosis, and accumulating cellular portion of G2/M phase via the induction of cyclin B1 and cyclin-dependent kinase p21(WAF1/CIP1). The phosphorylation of histone H3 was also markedly increased following treatment with DATS, revealing that DATS stimulated a mitotic arrest, not the G2 phase. Furthermore, we found that DATS concurrently induced phosphorylation of AMPK; however, chemical inhibition of AMPK by compound C, an AMPK inhibitor, significantly blocked apoptosis induced by DATS, suggesting that DATS induces cytotoxicity of AGS cells through the AMPK-dependent pathway. Moreover, DATS provoked intracellular ROS generation and the loss of mitochondrial membrane potential, and in particular, when ROS production was blocked by antioxidant N-acety-l-cysteine, both AMPK activation and growth inhibition by DATS were completely abolished. Collectively, these findings suggest that DATS inhibited growth of AGS cells, which was mediated by complex interplay between cellular mechanisms governing redox homeostasis, apoptosis, and cell cycle arrest, through a ROS-dependent activation of AMPK pathway.

Effect of borrelidin on hepatocellular carcinoma cells in vitro and in vivo

Hepatocellular carcinoma (HCC) is the most common type of liver cancer with high prevalence and mortality.