Redox Modulation and Induction of Ferroptosis as a New Therapeutic Strategy in Hepatocellular Carcinoma
Ferroptosis, a newly discovered form of cell death mediated by reactive oxygen species (ROS) and lipid peroxidation, has recently been shown to have an impact on various cancer types; however, so far there are only few studies about its role in hepatocellular carcinoma (HCC). The delicate equilibrium of ROS in cancer cells has found to be crucial for cell survival, thus increased levels may trigger ferroptosis in HCC. In our study, we investigated the effect of different ROS modulators and ferroptosis inducers on a human HCC cell line and a human hepatoblastoma cell line. We identified a novel synergistic cell death induction by the combination of Auranofin and buthionine sulfoxime (BSO) or by Erastin and BSO at subtoxic concentrations. We found a caspase-independent, redox-regulated cell death, which could be rescued by different inhibitors of ferroptosis. Both cotreatments stimulated lipid peroxidation. All these findings indicated ferroptotic cell death. Both cotreatments affected the canonical ferroptosis pathway through GPX4 downregulation. We also found an accumulation of Nrf2 and HO-1, indicating an additional effect on the non-canonical pathway. Our results implicate that targeting these two main ferroptotic pathways simultaneously can overcome chemotherapy resistance in HCC.
Expression of Nrf2 and NF-κB transcription factors in breast cancer and breast fibroadenoma: Insights for a new therapeutic approach
Cancer and fibroadenoma are the most common breast tumors in women of reproductive age. Nuclear factor erythroid 2-related factor 2 (Nrf2) and the nuclear factor kappaB (NF-κB) transcription factor play an important role in the inflammatory process and in cell proliferation. However, few studies have analyzed these markers in breast cancer and fibroadenoma in women of reproductive age. Light microscopy showed a higher concentration of anti-Nrf2 and anti-NF-κB-stained nuclei in breast cancer than in fibroadenoma. The mean percentage of stained nuclei for Nrf2 was 7.12 ± 5.2 and 43.21 ± 19.83 in the control and study groups, respectively (p < 0.0001). The mean percentage of anti-NF-κB was 10.75 ± 7.09 and 56.14 ± 21.19 (mean ± standard deviation) in the control and study groups, respectively (p < 0.0001). Histological grade 3 tumors showed a significantly higher expression of Nrf2 and NF-κB than grade 1 tumors (p < 0.05). This study was approved by the Institutional Review Board of Federal University of Piaui and all patients assigned an inform consent term prior to the study initiation. Nrf2 and NF-κB expression was evaluated by immunohistochemistry in 66 patients, divided into two groups, control (fibroadenoma, n = 36) and study (cancer, n = 30). The data were analyzed using ANOVA test and the statistical significance was established at p < 0.05. Nrf2 and NF-κB expression was significantly higher in breast cancer than in fibroadenoma, in addition to having a greater association with more aggressive tumors.
Inhibition of ferroptosis attenuates busulfan-induced oligospermia in mice
Busulfan is commonly used for cancer chemotherapy, nevertheless it cause male infertility via damaging the germ cells. Therefore, the underlying mechanism should be explored. In the present study, we demonstrated for the first time that ferroptosis was involved in busulfan-induced oligospermia in mice. Mice were given testicular injection of busulfan on both sides at the dose of 4 mg/kg body weight to establish the model of oligospermia. Four weeks later, the results showed that busulfan-treated mice exhibited decreased sperm concentration and motility, along with features of typical ferroptosis in testis, such as increased malondialdehyde (MDA) content and prostaglandin-endoperoxide synthase (PTGS2) mRNA expression, and decreased NADPH content. Inhibition of ferroptosis by ferrostatin-1 (Fer-1) or deferoxamine (DFO) partially alleviated busulfan-induced oligospermia in mice. Additionally, we also revealed that busulfan treatment induced spermatogenic cells ferroptosis by down-regulating nuclear factor-E2-related factor 2 (Nrf2) and glutathione peroxidase 4 (GPX4) expressions, and decreasing iron efflux through reduction of ferroportin 1 (FPN1) expression. Fer-1 or DFO obviously reversed busulfan-induced ferroptosis by increasing Nrf2, GPX4 and FPN1 expressions. Furthermore, after activation of Nrf2 by sulforaphane, sperm concentration and motility in busulfan-treated mice increased, accompanied by enhanced expressions of GPX4 and FPN1. These findings imply that busulfan-induced ferroptosis might be mediated via inhibition of Nrf2-GPX4 (FPN1) signaling pathway, and highlight that targeting ferroptosis serves as a potential strategy for prevention of busulfan-induced damage and male infertility.
Vinpocetine reduces cisplatin-induced acute kidney injury through inhibition of NF-κB pathway and activation of Nrf2/ARE pathway in rats
Acute kidney injury is a complex clinical disease that is associated with a high incidence of morbidity and mortality. Drug-induced acute kidney injury occurs in approximately 19-33% of hospitalized patients. Cisplatin, one of the most commonly used and effective chemotherapeutic drugs not only exerts anti-tumor effects but also causes renal toxicity damage, affecting its clinical application. Vinpocetine is an anti-inflammatory and antioxidant drug that predominately acts in the nervous system. In this study, we investigated the effects and mechanisms of vinpocetine in an animal model of cisplatin-induced acute renal injury. Rats were randomly divided into three experimental groups. During a 10-day trial, rats in the control group were administered a physiological saline solution; rats in the model group received a 5 mg/kg intraperitoneal injection of cisplatin; and rats in the cisplatin + vinpocetine group received a 5 mg/kg intraperitoneal injection of cisplatin as well as a 5 mg/kg dose of vinpocetine via gavage. We observed that following cisplatin administration, the rats exhibited an increase in blood urea and creatinine levels as well as an increase in their inflammation and oxidative stress levels. In renal tissue, cisplatin caused the morphological changes typical of acute tubular injury. Vinpocetine reduced the cisplatin-induced acute renal function damage and tubular injury. In both in vivo and in vitro experiments, we found that vinpocetine can confer protection of rat renal cells by inhibiting the NF-κB signaling pathway and activating the Nrf2/ARE signaling pathway. Therefore, vinpocetine is a promising therapeutic drug for the treatment of cisplatin-induced acute kidney injury.
Possible differences in the mechanism of malignant transformation of HaCaT cells by arsenite and its dimethyl metabolites, particularly dimethylthioarsenics
As a confirmed human carcinogen, arsenic can cause skin cancer, lung cancer, etc. However, its carcinogenic mechanism is still unclear. In recent years, the oxidative stress hypothesis has become widely accepted. In mammals it has been found that arsenic can be converted to dimethylarsinous acid (DMA) and dimethylmonothioarsinic acid (DMMTA) through a series of methylation and redox reactions. DMA and DMMTA are highly toxic.
The ameliorating effects of anthocyanins on the cross-linked signaling pathways of cancer dysregulated metabolism
Cancer cells underlie the dysregulated metabolism of carbohydrate, lipid and protein and thereby, employ interconnected cross-linked signaling pathways to supply adequate energy for growth and related biosynthetic procedures. In the present study, a comprehensive review of cancer metabolism and anthocyanin's effect was conducted using the existing electronic databases, including Medline, PubMed, Scopus, and Web of Science, as well as related articles in the field. Such keywords as "cancer", and "cancer metabolism" in the title/abstract/keyword and all the "anthocyanins" in the whole text were used. Data were collected without time restriction until February 2020. The results indicated the involvement of several signaling pathways, including inflammatory PI3K/Akt/mTOR pathway, Bax/Bcl-2/caspases as apoptosis modulators, and NF-κB/Nrf2 as oxidative stress mediators in the cancer dysregulated metabolism. Compelling studies have shown that targeting these pathways, as critical hallmarks of cancer, plays a critical role in combating cancer dysregulated metabolism. The complexity of cancer metabolism signaling pathways, along with toxicity, high costs, and resistance to conventional drugs urge the need to investigate novel multi-target agents. Increasing evidence has introduced plant-derived secondary metabolites as hopeful anticancer candidates which target multiple dysregulated cross-linked pathways of cancer metabolism. Amongst these metabolites, anthocyanins have demonstrated positive anticancer effects by targeting inflammation, oxidative stress, and apoptotic signaling pathways. The current study revealed the cross-linked signaling pathways of cancer metabolism, as well as the promising pharmacological mechanisms of anthocyanins in targeting the aforementioned signaling mediators. To overcome the pharmacokinetic limitations of anthocyanins in cancer treatment, their interactions with gut microbiota and the need to develop related nano-formulations were also considered.
MiR-27b-3p exerts tumor suppressor effects in esophageal squamous cell carcinoma by targeting Nrf2
MiR-27b-3p has been reported to function as tumor suppressor in several tumors, including breast cancer and lung cancer. Recently, miR-27b-3p has been identified to be significantly down-regulated in esophageal cancer. However, the clinical significance and biological role of miR-27b-3p in esophageal squamous cell carcinoma (ESCC) still remain unclear. In this study, the expression levels of miR-27b-3p were significantly reduced in ESCC clinical tissues and ESCC cell lines (EC97069 and TE-1). Moreover, down-regulated expression of miR-27b-3p was associated with poor cell differentiation, TNM stage and lymph node metastasis. Specially, overexpression of miR-27b-3p significantly suppressed cell proliferation, migration and invasion in vitro using CCK-8 and transwell assays. Targetscan bioinformatics predictions and luciferase reporter assay confirmed that nuclear factor erythroid 2-related factor 2 (NFE2L2, Nrf2) was a direct target gene of miR-27b-3p. Nrf2 expression was significantly increased in ESCC tissues compared with adjacent tissues. Up-regulated expression of Nrf2 was correlated with TNM stage and lymph node metastasis. Functionally, knockdown of Nrf2 exhibited similar effects to overexpression of miR-27b-3p. Higher expression of ZO-1, E-cadherin and lower expression of N-cadherin, Vimentin and Claudin-1 were observed after miR-27b-3p overexpression of Nrf2 knockdown. Rescue experiments proved that miR-27b-3p suppressed cell proliferation, migration, invasion and epithelial to mesenchymal transition (EMT) via suppression of Nrf2. Taken together, the newly identified miR-27b-3p/Nrf2 axis might represent a new candidate therapeutic target for ESCC treatment.
Exome sequencing identifies new somatic alterations and mutation patterns of tongue squamous cell carcinoma in a Chinese population
Tongue squamous cell carcinoma (TSCC) is an aggressive group of tumors characterized by high rates of regional lymph node metastasis and local recurrence. Emerging evidence has revealed genetic variations of TSCC across different geographical regions due to the impact of multiple risk factors such as chewing betel-quid. However, we know little of the mutational processes of TSCC in the Chinese population without the history of chewing betel-quid/tobacco. To explore the mutational spectrum of this disease, we performed whole-exome sequencing of sample pairs, comprising tumors and normal tissue, from 82 TSCC patients. In addition to identifying seven previously known TSCC-associated genes (TP53, CDKN2A, PIK3CA, NOTCH1, ASXL1, USH2A and CSMD3), the analysis revealed six new genes (GNAQ, PRG4, RP1, ZNF16, NBEA and PTPRC) that had not been previously been reported in TSCC. Our in vitro experiments identified ZNF16 for the first time as a solid tumor associated gene to promote malignancy of TSCC cells. We also identified a microRNA (miR-585-5p) encoded by the 5q35.1 region and characterized it as a tumor suppressor by targeting SOX9. At least one non-silent mutation of genes involved in the ten canonical oncogenic pathways (Notch, RTK-RAS, PI3K, Wnt, Cell cycle, p53, Myc, Hippo, TGFß and Nrf2) was found in 82.9% of cases. Collectively, our data extend the spectrum of TSCC mutations and define novel diagnosis markers and potential clinical targets for TSCC. This article is protected by copyright. All rights reserved.
TFAP2A is a novel regulator that modulates ferroptosis in gallbladder carcinoma cells via the Nrf2 signalling axis
Ferroptosis is a recently identified form of controlled cell death generally associated with the accumulation of lipid-associated reactive oxygen species (ROS). However, the molecular mechanisms underlying ferroptosis have not been established.
An integrative investigation on significant mutations and their down-stream pathways in lung squamous cell carcinoma reveals CUL3/KEAP1/NRF2 relevant subtypes
Molecular mechanism of lung squamous cell carcinoma (LUSC) remains poorly understood, hampering effective targeted therapies or precision diagnosis about LUSC. We devised an integrative framework to investigate on the molecular patterns of LUSC by systematically mining the genomic, transcriptional and clinical information.
The Role of Lysosome-Associated Membrane Protein 2 in Prostate Cancer Chemopreventive Mechanisms of Sulforaphane
Prostate cancer chemoprevention by sulforaphane (SFN), which is a metabolic by-product of glucoraphanin found in broccoli, in preclinical models is associated with induction of both apoptosis and autophagy. However, the molecular mechanism underlying SFN-mediated autophagy, which is protective against apoptotic cell death by this phytochemical, is still poorly understood. The present study demonstrates a role for lysosome-associated membrane protein 2 (LAMP2) in SFN-mediated autophagy and apoptosis. Western blotting revealed dose-dependent induction of LAMP2 protein after treatment with SFN as well as its naturally-occurring analogs in PC-3 and 22Rv1 human prostate cancer cell lines that was confirmed by microscopy (SFN). The mRNA level of LAMP2 was also increased upon treatment with SFN in both cell lines. SFN-mediated increase in the level of autophagy marker microtubule-associated protein light-chain 3B (LC3BII) was augmented by RNA interference of LAMP2 in PC-3 and 22Rv1 cells. Apoptosis induction by SFN treatment was also increased significantly by knockdown of the LAMP2 protein in PC-3 and 22Rv1 cells. Augmentation of SFN-mediated apoptosis by RNA interference of LAMP2 was accompanied by induction and activation of pro-apoptotic protein Bak. Oral administration of SFN to TRAMP mice also resulted in induction of LAMP2 protein expression. Targeted microarray in SFN-treated PC-3 cells revealed induction of many autophagy-related genes (e.g., HSP90AA1, NRF2, etc.) and their expression positively correlated with that of LAMP2 in prostate cancer TCGA. In conclusion, the present study reveals that induction of LAMP2 by SFN inhibits its ability to induce apoptotic cell death at least in human prostate cancer cells.
Luteolin alleviates ochratoxin A induced oxidative stress by regulating Nrf2 and HIF-1α pathways in NRK-52E rat kidney cells
Ochratoxin A (OTA) is a ubiquitous food contaminant and a critical food safety concern due to its nephron toxic effects, which impacts all parts of the world. Luteolin (LUT) had gained increasing interest as a health-promoting food antioxidant component. However, the preventative effect of LUT against OTA induced oxidative stress was not yet clear and the elucidation of which would provide critical information to develop dietary LUT as a control strategy for OTA. In the current study, the cytoprotective effect of LUT against OTA induced oxidative stress and the mechanism(s) behind was examined in NRK-52E rat kidney cells. The results showed that LUT exerted its preventative effect via restoring cell viability and preventing LDH release. It alleviated the OTA-induced oxidative stress and lipid peroxidation by reducing ROS accumulation, ameliorating the mitochondrial membrane potential reduction and reversing the activities of antioxidant enzymes to the control levels. The regulating roles of Nrf2 and HIF-1α in this process were evaluated by cell immunofluorescence assay, reporter plasmids transfection assay and qRT-PCR analysis. The results showed that LUT activated Nrf2 pathway and increased the antioxidant defense capacities of OTA treated cells. Additionally, LUT also modulated HIF-1α pathway to initiate the angiogenesis and epithelial restitution process.
Photoprotective Properties of Vitamin D and Lumisterol Hydroxyderivatives
We have previously described new pathways of vitamin D3 activation by CYP11A1 to produce a variety of metabolites including 20(OH)D3 and 20,23(OH)D3. These can be further hydroxylated by CYP27B1 to produce their C1α-hydroxyderivatives. CYP11A1 similarly initiates the metabolism of lumisterol (L3) through sequential hydroxylation of the side chain to produce 20(OH)L3, 22(OH)L3, 20,22(OH)L3 and 24(OH)L3. CYP11A1 also acts on 7-dehydrocholesterol (7DHC) producing 22(OH)7DHC, 20,22(OH)7DHC and 7-dehydropregnenolone (7DHP) which can be converted to the D3 and L3 configurations following exposure to UVB. These CYP11A1-derived compounds are produced in vivo and are biologically active displaying anti-proliferative, anti-inflammatory, anti-cancer and pro-differentiation properties. Since the protective role of the classical form of vitamin D3 (1,25(OH)D3) against UVB-induced damage is recognized, we recently tested whether novel CYP11A1-derived D3- and L3-hydroxyderivatives protect against UVB-induced damage in epidermal human keratinocytes and melanocytes. We found that along with 1,25(OH)D3, CYP11A1-derived D3-hydroxyderivatives and L3 and its hydroxyderivatives exert photoprotective effects. These included induction of intracellular free radical scavenging and attenuation and repair of DNA damage. The protection of human keratinocytes against DNA damage included the activation of the NRF2-regulated antioxidant response, p53-phosphorylation and its translocation to the nucleus, and DNA repair induction. These data indicate that novel derivatives of vitamin D3 and lumisterol are promising photoprotective agents. However, detailed mechanisms of action, and the involvement of specific nuclear receptors, other vitamin D binding proteins or mitochondria, remain to be established.
Research Progress on Long Non-coding RNAs and Drug Resistance of Breast Cancer
Breast cancer, as the foremost cause of women's death in the world, is highly metastatic and mutable. Resistance to drugs for chemotherapies, endocrine therapies, and targeted therapies is an important factor that impacts the prognosis of breast cancer. Long non-coding ribonucleic acids (LncRNAs) are crucial regulators of intracellular gene expressions. Some researchers have suggested that expression level of several types of LncRNAs were closely related to the prognosis of patients with breast cancer. LncRNAs significantly impact biological processes such as drug transport, detoxication, apoptosis, epithelial to mesenchymal transition (EMT), and autophagy by regulating intracellular signaling pathways such as multi-drug resistance gene 1 (MDR1), nuclear factor erythroid 2-related factor 2 (NRF2), phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR), transforming growth factor-β (TGF-β), BRCA1/2, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). This paper will summarize research progress on correlations between LncRNA and drug resistance of breast cancer. It will particularly expound molecular mechanisms through which LncRNAs regulate drug resistance of breast cancer. It will further discuss the feasibility as molecular markers for forecasting drug resistance of breast cancer and may be becoming new targets for treating breast cancer in the future.
Sulforaphane Potentiates Anticancer Effects of Doxorubicin and Cisplatin and Mitigates Their Toxic Effects
The success of cancer therapy is often compromised by the narrow therapeutic index of many anticancer drugs and the occurrence of drug resistance. The association of anticancer therapies with natural compounds is an emerging strategy to improve the pharmaco-toxicological profile of cancer chemotherapy. Sulforaphane, a phytochemical found in cruciferous vegetables, targets multiple pathways involved in cancer development, as recorded in different cancers such as breast, brain, blood, colon, lung, prostate, and so forth. As examples to make the potentialities of the association chemotherapy raise, here we highlight and critically analyze the information available for two associations, each composed by a paradigmatic anticancer drug (cisplatin or doxorubicin) and sulforaphane.