Suppression of cell proliferation, DNA protein cross-links, and induction of apoptosis by vanadium in chemical rat mammary carcinogenesis

Chitosan Nanoparticle-Mediated Delivery of Alstonia venenata R.Br. Root Methanolic Extract: A Promising Strategy for Breast Cancer Therapy in DMBA-Induced Breast Cancer in Sprague Dawley Rats

Alstonia venenata R.Br., a plant native to the Western Ghats, is recognized for its diverse medicinal properties. The plant's extracts, particularly rich in alkaloids and other bioactive compounds, have shown potential anticancer activity. This study investigates the therapeutic potential of chitosan nanoparticles (CNPs) loaded with the root methanolic extract (RME) of A. venenata in combating breast cancer induced by dimethylbenz(a)anthracene (DMBA) in female Sprague Dawley rats. The RME-loaded chitosan nanoparticles (RME-EnCNPs) were synthesized and characterized, and their in vivo efficacy was evaluated. Treatment with RME-EnCNPs significantly inhibited tumor progression, which is evidenced by reduced tumor volume, burden, and incidence. Moreover, the nanoparticles demonstrated a sustained release of the active compounds, leading to marked improvements in various biochemical, enzymatic, and histopathological parameters. The study found that both RME and RME-EnCNPs effectively suppressed tumor growth, with RME-EnCNPs showing superior efficacy in modulating tumor progression. Antioxidant assays revealed that treatment with RME-EnCNPs (500 mg/kg) resulted in significant increases in total protein, superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), and glutathione (GSH) levels, alongside a marked reduction in lipid peroxidation (LPO) (p < 0.001). These findings suggest that RME-EnCNPs exert a potent antioxidant effect, mitigating oxidative stress within the tumor microenvironment. The root extract of A. venenata and its nanoparticle formulation hold promise as a potential therapeutic agent for breast cancer, warranting further investigation to isolate active bioactive compounds and elucidate their mechanisms of action.

Biological Consequences of Vanadium Effects on Formation of Reactive Oxygen Species and Lipid Peroxidation

Lipid peroxidation (LPO), a process that affects human health, can be induced by exposure to vanadium salts and compounds. LPO is often exacerbated by oxidation stress, with some forms of vanadium providing protective effects. The LPO reaction involves the oxidation of the alkene bonds, primarily in polyunsaturated fatty acids, in a chain reaction to form radical and reactive oxygen species (ROS). LPO reactions typically affect cellular membranes through direct effects on membrane structure and function as well as impacting other cellular functions due to increases in ROS. Although LPO effects on mitochondrial function have been studied in detail, other cellular components and organelles are affected. Because vanadium salts and complexes can induce ROS formation both directly and indirectly, the study of LPO arising from increased ROS should include investigations of both processes. This is made more challenging by the range of vanadium species that exist under physiological conditions and the diverse effects of these species. Thus, complex vanadium chemistry requires speciation studies of vanadium to evaluate the direct and indirect effects of the various species that are present during vanadium exposure. Undoubtedly, speciation is important in assessing how vanadium exerts effects in biological systems and is likely the underlying cause for some of the beneficial effects reported in cancerous, diabetic, neurodegenerative conditions and other diseased tissues impacted by LPO processes. Speciation of vanadium, together with investigations of ROS and LPO, should be considered in future biological studies evaluating vanadium effects on the formation of ROS and on LPO in cells, tissues, and organisms as discussed in this review.

Apple polyphenol phloretin complexed with ruthenium is capable of reprogramming the breast cancer microenvironment through modulation of PI3K/Akt/mTOR/VEGF pathways

Our recent investigation directed to synthesize a novel ruthenium-phloretin complex accompanied by the study of antioxidant in addition to DNA binding capabilities, to determine the chemotherapeutic activity against breast carcinoma in vitro and in vivo. Ruthenium-phloretin complex was synthesized and characterized by different spectroscopic methods. The complex was further investigated to determine its efficacy in both MCF-7 and MDA-MB-231 human carcinoma cell lines and finally in an in vivo model of mammary carcinogenesis induced by DMBA in rats. Our studies confirm that the chelation of the metal and ligand was materialize by the 3-OH and 9-OH functional groups of the ligand and the complex is found crystalline and was capable of intercalating with CT-DNA. The complex was capable of reducing cellular propagation and initiate apoptotic events in MCF-7 and MDA-MB-231 breast carcinoma cell lines. Ruthenium-phloretin complex could modulate p53 intervene apoptosis in the breast carcinoma, initiated by the trail of intrinsic apoptosis facilitated through Bcl2 and Bax and at the same time down regulating the PI3K/Akt/mTOR pathway coupled with MMP9 regulated tumor invasive pathways. Ruthenium-phloretin chemotherapy could interrupt, revoke or suspend the succession of breast carcinoma by altering intrinsic apoptosis along with the anti-angiogenic pathway.

The Effect of Vanadium Inhalation on the Tumor Progression of Urethane-Induced Lung Adenomas in a Mice Model

Lung cancer has the highest death rates. Aerosol drug delivery has been used for other lung diseases. The use of inhaled vanadium (V) as an option for lung cancer treatment is explored. Four groups of mice were studied: (1) Saline inhalation alone, (2) Single intraperitoneal (i.p.) dose of urethane, (3) V nebulization twice a week (Wk) for 8 Wk, and (4) A single dose of urethane and V nebulization for 8 Wk. Mice were sacrificed at the end of the experiment. Number and size of tumors, PCNA (proliferating cell nuclear antigen) and TUNEL (terminal deoxynucleotidyl tranferase dUTP nick-end labeling) immunohistochemistry were evaluated and compared within groups. Results: The size and number of tumors decreased in mice exposed to V-urethane and the TUNEL increased in this group; differences in the PCNA were not observed. Conclusions: Aerosol V delivery increased apoptosis and possibly the growth arrest of the tumors with no respiratory clinical changes in the mice.

A Novel Ruthenium-Fluvastatin Complex Downregulates SNCG Expression to Modulate Breast Carcinoma Cell Proliferation and Apoptosis via Activating the PI3K/Akt/mTOR/VEGF/MMP9 Pathway

Breast cancer is the most common cause of malignancy and cancer-related morbidity and death worldwide that requests effective and safe chemotherapy. Evaluation of metallodrug-based anticancer agents and statins as chemotherapeutics with fewer side effects is a largely unexplored research field. Synthesis and characterization of the ruthenium-fluvastatin complex were achieved using multiple spectroscopic techniques and thus further examined to evaluate its chemotherapeutic prospects in both MDA-MB-231 and MCF-7 cancer lines and eventually in vivo models of DMBA-induced mammary carcinogenesis in rodents. Our studies indicate that the metal and ligand chelation was materialized by the ligand's functional groups of carbonyl (=O) oxygen and hydroxyl (-OH), and the complex has been observed to be crystalline and able to chelate with CT-DNA. The complex was able to reduce cell proliferation and activate apoptotic events in breast carcinoma cell lines MCF-7 and MDA-MB-231. In addition, the complex was able to modify p53 expressions to interfere with apoptosis in the carcinoma of the breast, stimulated by the intrinsic apoptotic path assisted by Bcl2 and Bax in vivo, yet at the same point, controlling the PI3K/Akt/mTOR/VEGF pathway, as obtained from western blotting, correlates with the MMP9-regulated tumor mechanisms. Our research reveals that ruthenium-fluvastatin chemotherapy may disrupt, rescind, or interrupt breast carcinoma progression by modifying intrinsic apoptosis as well as the antiangiogenic cascade, thereby taking the role of a potential candidate in cancer therapy for the immediate future.

Anticancer effect of sodium metavanadate on murine breast cancer both in vitro and in vivo

Sodium metavanadate (NaVO₃) exhibits important physiological effects including insulin-like, chemoprevention and anticancer activity. However, the effects of NaVO₃ on breast cancer and underlying mechanisms are still unclear. In this study, our results revealed that NaVO₃ was able to inhibit proliferation of murine breast cancer cells 4T1 with IC₅₀ value of 8.19 μM and 1.92 μM at 24 h and 48 h, respectively. The mechanisms underlying the inhibition activity were that NaVO₃ could increase reactive oxygen species (ROS) level in a concentration-dependent way, arrest cells at G2/M phase, diminish the mitochondrial membrane potential (MMP), finally promote the progress of apoptosis. Furthermore, NaVO₃ also exhibited a dose-dependent anticancer activity in breast cancer-bearing mice that led to the shrinkage of tumor volume (about 50%), lower microvessel density, less propagating cells and more apoptotic cells in vivo, as compared to the saline group. Therefore, NaVO₃ may act as a potential chemotherapeutic agent in breast cancer treatment.

Potentiating apoptosis and modulation of p53, Bcl2, and Bax by a novel chrysin ruthenium complex for effective chemotherapeutic efficacy against breast cancer

Breast cancer is the most frequent cause of cancer in women. In the current study, transition metal ruthenium was complexed with flavonoid chrysin to evaluate the chemotherapeutic potential of this compound in Michigan Cancer Foundation-7 (MCF-7) human mammary cancer cell line and 7,12-dimethylbenz(α)anthracene-induced mammary cancer in female Sprague-Dawley rats. The characterizations of the complex were accomplished through UV-visible, NMR, IR, Mass spectra, and XRD techniques and antioxidant activity was assessed by DPPH, FRAP, and ABTS methods. In vitro studies included cell viability, cell cycle analysis, DNA fragmentation, and marker analysis by western blot analysis and found that complex treatment suppressed cell growth-induced cell cycle arrest and enhanced the induction of apoptosis in cancer cells. Moreover, complex treatment modulated signaling pathways including mTOR, VEGF, and p53 in the MCF-7 cells. Acute and subacute toxicity was performed in rats to determine the therapeutic doses. Breast cancer in rats was initiated by the administration of 7,12-dimethylbenz(α)anthracene (0.5 mg/100 g body weight) via single tail vein injection. The histopathological analysis after 24 weeks of carcinogenesis study depicted substantial repair of hyperplastic lesions. Immunohistochemical analysis revealed upregulation of Bax and p53 and downregulation of Bcl2 proteins and TUNEL assay showed an increase in apoptotic index in ruthenium-chrysin-treated groups as compared to the carcinogen control. Our findings from the in vitro and in vivo study support the continued investigation of ruthenium-chrysin complex possesses a potential chemotherapeutic activity against breast cancer and was efficient in reducing hyperplastic lesions in the mammary tissues of rats by inducing apoptosis.

Biochemical studies evaluating the chemopreventive potential of brucine in chemically induced mammary carcinogenesis of rats

The present study was aimed to investigate the dose dependent chemopreventive activity of brucine against 7, 12-dimethylbenz (a) anthracene induced mammary gland tumorigenesis in rats. The mammary tumor was induced by a single dose of DMBA (25 mg/rat) injected subcutaneously near the mammary gland. We observed reduced body weight and increase in tumor incidence, the total number of tumors, and tumor volume in DMBA alone injected rats and also observed decreased antioxidant status (SOD, CAT, GPX, and GSH) and increased lipid peroxidation (TBARS and LOOH) in plasma and mammary tissues. Increased levels of CYP450, Cyt-b5 and decreased levels of phase II (GST and GR) biotransformation enzymes were noticed in the liver and mammary tissues. Further, increased levels of lipid profile (TC, TG, PL, and FFA) and lipoprotein (LDL and VLDL) were noticed. Whereas, decrease in the levels of HDL in plasma and decreased levels of PL and FFA in mammary tissues were observed. Oral administration of brucine in different doses (2, 4 and 8 mg/kg bw) inhibited the tumor incidence and restored the levels of biochemical markers near to normal in dose responsive manner. Biochemical findings are supported by histopathological studies. The results suggest that brucine at a dose of 8 mg/kg bw shows more significant chemopreventive activity in DMBA-induced mammary carcinogenesis.

Vanadium quercetin complex attenuates mammary cancer by regulating the P53, Akt/mTOR pathway and downregulates cellular proliferation correlated with increased apoptotic events

Flavonoid metal ion complexes have been deliberated in recent years and are considered as a new class of medicinal agents with enhanced therapeutic activity and low toxicity. Our study deals with chemotherapeutic effects of vanadium, when coordinated with the flavonoid quercetin on a defined model of chemically induced rat mammary carcinogenesis in vivo and on human breast cancer cell line MCF-7 in vitro. The characterization of the complex was achieved through UV-Visible, IR, and Mass spectra and antioxidant activity was assessed by DPPH, FRAP and ABTS methods. In vitro studies established that the complex upregulated the expressions of p53, Caspase 3 and 9, whereas down regulating Akt, mTOR and VEGF expressions and also induced apoptosis and DNA fragmentation in a dose dependent manner. Acute and Sub-acute toxicity was performed to determine safe doses. 7,12-Dimethylbenz(α)anthracene (0.5 mg/100 g body weight) was used for induction of breast cancer in female Sprague-Dawley rats via single tail vein injection. The histopathological analysis after 24 weeks of carcinogenesis study depicted substantial repair of hyperplastic lesions. TUNEL assay showed an increase in apoptotic index (0.14 ± 0.03; 0.15 ± 0.01) in vanadium-quercetin treated groups as compared to the carcinogen control (0.02 ± 0.01) along with upregulation of Bcl-2 and downregulation of Bax and p53. Immunohistochemical analysis also exhibited decrease in cell proliferation in the vanadium-quercetin treated groups (11.3 ± 0.12; 11.8 ± 0.10). Thus, results from both in vivo and in vitro studies revealed that vanadium-quercetin complex could be a potential candidate for development of approved drug for breast cancer in the near future.

Vanadium Compounds as PTP Inhibitors

Phosphotyrosine signaling is regulated by the opposing actions of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs). Here we discuss the potential of vanadium derivatives as PTP enzyme inhibitors and metallotherapeutics. We describe how vanadate in the V oxidized state is thought to inhibit PTPs, thus acting as a pan-inhibitor of this enzyme superfamily. We discuss recent developments in the biological and biochemical actions of more complex vanadium derivatives, including decavanadate and in particular the growing number of oxidovanadium compounds with organic ligands. Pre-clinical studies involving these compounds are discussed in the anti-diabetic and anti-cancer contexts. Although in many cases PTP inhibition has been implicated, it is also clear that many such compounds have further biochemical effects in cells. There also remain concerns surrounding off-target toxicities and long-term use of vanadium compounds in vivo in humans, hindering their progress through clinical trials. Despite these current misgivings, interest in these chemicals continues and many believe they could still have therapeutic potential. If so, we argue that this field would benefit from greater focus on improving the delivery and tissue targeting of vanadium compounds in order to minimize off-target toxicities. This may then harness their full therapeutic potential.

Ameliorative effect of an oxovanadium (IV) complex against oxidative stress and nephrotoxicity induced by cisplatin

OBJECTIVE

The present study was designed to investigate the chemoprotective efficacy of an L-cysteine-based oxovanadium (IV) complex, namely, oxovanadium (IV)-L-cysteine methyl ester complex (VC-IV) against cisplatin (CDDP)-induced renal injury in Swiss albino mice.

METHODS

CDDP was administered intraperitoneally (5 mg/kg body weight) and VC-IV was administered orally (1 mg/kg body weight) in concomitant and 7 days pre-treatment schedule.

RESULTS

CDDP-treated mice showed marked kidney damage and renal failure. Administration of VC-IV caused significant attenuation of renal oxidative stress and elevation of antioxidant status. VC-IV also significantly decreased serum levels of creatinine and blood urea nitrogen, and improved histopathological lesions. Western blot analysis of the kidneys showed that VC-IV treatment resulted in nuclear translocation of nuclear factor E2-related factor 2 (Nrf2) through modulation of cytosolic Kelch-like ECH-associated protein 1. Thus, VC-IV stimulated Nrf2-mediated activation of antioxidant response element (ARE) pathway and promoted expression of ARE-driven cytoprotective proteins, heme oxygenase 1 and NAD(P)H:quinone oxidoreductase 1, and enhanced activity of antioxidant enzymes. Interestingly, VC-IV did not alter the bioavailability and renal accumulation of CDDP in mice.

DISCUSSION

In this study, VC-IV exhibited strong nephroprotective efficacy by restoring antioxidant defense mechanisms and hence may serve as a promising chemoprotectant in cancer chemotherapy.

Stimulation of apoptotic pathways in liver cancer cells: An alternative perspective on the biocompatibility and the utility of biomedical glasses

A host of research opportunities with innumerable clinical applications are open to biomedical glasses if one considers their potential as therapeutic inorganic ion delivery systems. Generally, applications have been limited to repair and regeneration of hard tissues while compositions are largely constrained to the original bioactive glass developed in the 1960s. However, in oncology applications the therapeutic paradigm shifts from repair to targeted destruction. With this in mind, the composition–structure–property–function relationships of vanadium-containing zinc-silicate glasses (0.51SiO2–0.29Na2O–(0.20- X)ZnO– XV2O5, 0 ≤  X ≤ 0.09) were characterized in order to determine their potential as therapeutic inorganic ion delivery systems. Increased V2O5 mole fraction resulted in a linear decrease in density and glass transition temperature (Tg). 29Si MAS NMR peak maxima shifted upfield while 51V MAS NMR peak maxima were independent of V2O5 content and overlapped well with the spectra NaVO3. Increased V2O5 mole fraction caused ion release to increase. When human liver cancer cells, HepG2, were exposed to these ions they demonstrated a concentration-dependent cytotoxic response, mediated by apoptosis. This work demonstrates that the zinc-silicate system studied herein is capable of delivering therapeutic inorganic ions at concentrations that induce apoptotic cell death and provide a simple means to control therapeutic inorganic ion delivery.

Vanadium(III)-L-cysteine protects cisplatin-induced nephropathy through activation of Nrf2/HO-1 pathway

Cisplatin (CDDP) is one of the first-line anticancer drugs; however, the major limitation of CDDP therapy is development of nephrotoxicity (25-35% cases), whose precise mechanism mainly involves oxidative stress, inflammation and cell death. Therefore, in search of a potential chemoprotectant, an organovanadium complex, viz., vanadium(III)-L-cysteine (VC-III) was evaluated against CDDP-induced nephropathy in mice. CDDP was administered intraperitoneally (5 mg/kg b.w.) and VC-III was given by oral gavage (1 mg/kg b.w.) in concomitant and pre-treatment schedule. The results showed that VC-III administration reduced (p < 0.001) serum creatinine and blood urea nitrogen levels, suggesting amelioration of renal dysfunction. VC-III treatment also significantly (p < 0.001) prevented CDDP-induced generation of reactive oxygen species, reactive nitrogen species, and onset of lipid peroxidation in kidney tissues of the experimental mice. In addition, VC-III also substantially (p < 0.001) restored CDDP-induced depleted activities of the renal antioxidant enzymes such as, superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, and glutathione (reduced) level. Furthermore, histopathological study also confirmed the renoprotective efficacy of VC-III. Western blotting analysis appended by immunohistochemical data showed that VC-III treatment quite effectively reduced the expression of proinflammatory mediators such as, NFκβ, COX-2 and IL-6. VC-III administration also stimulated Nrf2-mediated antioxidant defense system by promotion of downstream antioxidant enzymes, such as HO-1. Moreover, treatment with VC-III significantly (p < 0.001) enhanced CDDP-mediated cytotoxicity in MCF-7 and NCI-H520 human cancer cell lines. Thus, VC-III can serve as a suitable chemoprotectant and increase the therapeutic window of CDDP in cancer patients.

Prevention of myelosuppression and genotoxicity induced by cisplatin in murine bone marrow cells: effect of an organovanadium compound vanadium(III)-l-cysteine

Cisplatin (CDDP) is one of the first-line anticancer drugs indicated for use against various form of human malignancies; but, the therapeutic outcome of CDDP chemotherapy is limited due to the development of myelosuppression and genotoxicity which may lead to secondary cancer. Induction of oxidative stress in normal host cells is thought to be responsible for these adverse effects. Therefore, in search of a potential chemoprotectant, an oraganovanadium compound, viz., vanadium(III)-l-cysteine (VC-III) was evaluated against CDDP-induced clastogenicity and cytotoxicity in bone marrow cells of Swiss albino mice. CDDP was administered intraperitoneally (5mg/kg body weight [b.w.]) and VC-III was given by oral gavage (1mg/kg b.w.) in concomitant and pretreatment schedule. The results showed that VC-III administration significantly (P < 0.001) enhanced cell proliferation and inhibited apoptosis in the bone marrow niche indicating recovery of CDDP-induced myelosuppression. VC-III also significantly (P < 0.001) decreased the percentage of chromosomal aberrations, the frequency of micronuclei formation and the extent of DNA damage. The observed antigenotoxic and cytoprotective effect of VC-III was attributed to its attenuation of free radicals status and restoration of oxidised and reduced glutathione levels. These results suggest that VC-III is a potential candidate for future development as a chemoprotective agent against chemotherapy-associated primary and secondary complications.

Dose response chemopreventive potential of allyl isothiocyanate against 7,12-dimethylbenz(a)anthracene induced mammary carcinogenesis in female Sprague-Dawley rats

The present study aimed to investigate the dose response chemopreventive potential of allyl isothiocyanate (AITC) against 7,12-dimethylbenz(a)anthracene (DMBA) induced mammary carcinogenesis in female Sprague-Dawley rats. Mammary tumor was induced by a single dose of DMBA (25 mg/rat) injected subcutaneously near mammary gland. We observed reduced body weight and increased in total number of tumors, tumor incidence and tumor volume in DMBA-induced rats. We also observed decreased antioxidant status (SOD, CAT, GPX and GSH) and increased lipid peroxidation (TBARS and LOOH) in plasma and mammary tissues. Increased levels of CYP450, Cyt-b5 and decreased levels of phase II (GST and GR) biotransformation enzymes noticed in liver and mammary tissues of DMBA-induced rats. Further, increased levels of lipid profile (TC, TG, PL and FFA) and lipoprotein (LDL and VLDL) were noticed. Whereas, decreased level of HDL in plasma and decreased levels of PL and FFA in mammary tissue. Oral administration of AITC different doses (10, 20 and 40 mg/kg bw) inhibited the tumor incidence and restored levels of biochemical markers. Biochemical findings are supported by histopathological studies. These results suggested that AITC at a dose of 20 mg/kg bw significantly exert chemopreventive potential against DMBA-induced mammary carcinogenesis.

Avermectin induced liver injury in pigeon: mechanisms of apoptosis and oxidative stress

Extensive use of avermectin (AVM) can result in environment pollution, and it is important to evaluate the potential impact this antibiotic has on ecological systems. Few published literatures have discussed the liver injury mechanisms induced by AVM on birds. In this study, pigeons were exposed to feed containing AVM (0, 20, 40 and 60 mg/kg diet) for 30, 60, 90 days respectively. The results showed that AVM increased the number of apoptosis and the expression level of caspase-3, 8, fas mRNA in the liver of pigeons. Ultrastructural alterations, including mitochondrial damage and chromatin aggregation, become severe with increase exposure dose. Exposure to AVM induced significant changes in antioxidant enzyme {superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px)} activities and malondialdehyde (MDA) content, augmented protein carbonyl (PCO) content and DNA-protein crosslink (DPC) coefficient, in a concentration-dependent manner in the liver of pigeons. Our results show that AVM has toxic effect in pigeon liver, and the mechanism of injury caused by AVM is closely related to apoptosis and oxidative stress.

Nitrogen dioxide inhalation induces genotoxicity in rats

Nitrogen dioxide (NO(2)) is a ubiquitous reactive free-radical gas, which has been associated with momentary and chronic health effects. In the present study, comet, micronucleus (MN) and DNA-protein crosslinks (DPC) assays were used to investigate the genotoxicity following in vivo inhalation exposure of rats to NO(2). The results show that inhalation exposure of rats to NO(2) induced DNA strand breakage and the formation of DPC in the cells from various internal organs (brain, lung, liver, spleen, kidney and heart), as well as resulted in obvious increase of MN frequency in the bone marrow cells of rats. Furthermore, above genotoxic responses showed significant linear dose-dependent manners. These results implicate that NO(2) is a genotoxic agent and these observations are informative for understanding the mechanisms of adverse effects of nitrogen dioxide.

Vanadium in the detection, prevention and treatment of cancer: the in vivo evidence

Vanadium, a dietary micronutrient, is yet to be established as an essential part of the human diet. Over the past century, several biological effects of vanadium, such as insulin-mimetic action as well as amelioration of hyperlipidemia and hypertension, have been discovered. This transition element is known to influence a battery of enzymatic systems, namely phosphatases, ATPases, peroxidases, ribonucleases, protein kinases and oxidoreductases. Multiple biochemical and molecular actions of vanadium have been implicated in its inhibitory effects on various tumor cells of human origin. Successful in vitro studies over the past few decades have advanced the anticancer research on vanadium into the preclinical stage. Vanadium in several animal cancer models provides protection against all stages of carcinogenesis--initiation, promotion, and progression. This review focuses on the current advances in cancer prevention and treatment as well as early detection by vanadium compounds in preclinical animal models while pointing to possible mechanisms of such diverse beneficial effects. Clinical pharmacokinetic and potential toxicity studies on vanadium are also highlighted in this review. Supporting and challenging evidence as well as future directions of vanadium research exploring the possibility of using this dietary agent for detection, prevention and treatment of human cancers are critically discussed.

SO(2) inhalation induces protein oxidation, DNA-protein crosslinks and apoptosis in rat hippocampus

Previous studies provide evidence for the possible neurotoxicity of SO(2), but little information is available about its mechanisms. In the present study, SO(2) inhalation-induced effects on the protein oxidation, DNA-protein crosslinks and apoptosis in rat hippocampus were studied, by exposing Wistar rats to SO(2) at 14, 28 and 56mg/m(3). The results indicate that the protein carbonyl content, an indicator of protein oxidation, and DNA-protein crosslink coefficient were significantly augmented with concentration-dependent properties. In addition, SO(2) inhalation at all concentrations tested caused the increases of caspase-3 activity and number of TUNEL positive staining neuron and the statistical difference was observed after 28 and 56mg/m(3) exposure, suggesting the occurrence of apoptosis. The results imply that attacking protein, nucleic acids and lipids by free radicals, generated via SO(2) derivatives in vivo, is one of the main mechanisms for SO(2)-induced injuries in central neuronal system.

Environmental toxicity, oxidative stress and apoptosis: ménage à trois

Apoptosis is an evolutionary conserved homeostatic process involved in distinct physiological processes including organ and tissue morphogenesis, development and senescence. Its deregulation is also known to participate in the etiology of several human diseases including cancer, neurodegenerative and autoimmune disorders. Environmental stressors (cytotoxic agents, pollutants or toxicants) are well known to induce apoptotic cell death and to contribute to a variety of pathological conditions. Oxidative stress seems to be the central element in the regulation of the apoptotic pathways triggered by environmental stressors. In this work, we review the established mechanisms by which oxidative stress and environmental stressors regulate the apoptotic machinery with the aim to underscore the relevance of apoptosis as a component in environmental toxicity and human disease progression.

Suppression of cell proliferation, induction of apoptosis and cell cycle arrest: chemopreventive activity of vanadium in vivo and in vitro

In the present study, the authors evaluated the anticancer mechanism of vanadium, a dietary micronutrient and an important pharmacological agent, on a defined model of chemically induced rat mammary carcinogenesis in vivo and on human breast cancer cell line MCF7 in vitro. Female Sprague-Dawley rats were treated with 7,12-dimethylbenz(alpha)anthracene (0.5 mg/100 g body weight) by a single tail vein injection in an oil emulsion to induce mammary preneoplasia. Vanadium (ammonium monovanadate) at a concentration of 0.5 ppm (4.27 micromol/l) was supplemented in drinking water and given ad libitum to the experimental groups for 24 weeks. Histological finding showed substantial repair of hyperplastic lesions. There was a significant reduction in incidence, multiplicity (34%, p < 0.01), size of palpable mammary tumors and delay in mean latency period of tumor appearance. Immunohistochemical analysis in vivo indicated a decrease in cell proliferation (24.68% p < 0.05) and an increase among the TUNEL-positive apoptotic cells along with strong expressions of p53 and Bax, and downregulation of Bcl2 proteins in the mammary tissue of vanadium-treated animals. Further, MCF7 cells were cultured in minimal essential medium and were treated with 100, 175 and 250 microM of vanadium (ammonium monovanadate) for 36 hr. Exposure of MCF7 cells to vanadium led to induction of apoptosis in a dose-dependent manner. It was found further that vanadium treatment brought about a prominent cell cycle arrest and chromosomal condensation, leading to apoptosis (42.62%, p < 0.05). Results of both the in vivo and in vitro study demonstrate that vanadium has the potential to be developed into an anti-breast cancer drug in the near future.

EFFECT OF TIRON AND ITS COMBINATION WITH NUTRITIONAL SUPPLEMENTS AGAINST VANADIUM INTOXICATION IN FEMALE ALBINO RATS

In the present study an attempt has been made to evaluate the effect of Tiron along with Zinc, Selenium and Vitamin E against vanadium intoxication in female albino rats. Toxicant caused significant increase in the activities of serum transaminases, serum alkaline phosphatase and lactate dehydrogenase. Significant decrease was observed in blood sugar, serum albumin and triglyceride levels whereas serum proteins, cholesterol and urea levels increased significantly during toxicity (p </= 0.001). Hepatic lipid peroxidation increased significantly, whereas significant depletion was observed in reduced glutathione after vanadium administration. The activity of glucose-6-phosphatase in the liver was also inhibited significantly after vanadium administration. A significant rise was observed in glycogen content of liver and kidney after toxicant exposure. Activities of alkaline phosphatase, adenosine triphosphatase and succinic dehydrogenase were inhibited significantly on the contrary activity of acid phosphatase elevated in kidney. Histopathological examination of the liver and kidney using light and ultramicroscopic study also substantiated the above findings. It was found that therapy with Tiron was effective but significant recovery in all the parameters was found with Tiron + Se followed by Tiron+ VitE and Tiron +Zn.