Arsenic trioxide induces apoptosis and inhibits the growth of human liver cancer cells.

AIMS: As a fifth most common cancer type, Hepatocellularcarcinoma (HCC) ranked third leading cause of cancer deaths worldwide. Arsenic trioxide (As2O3) is known as chemotherapeutic agent against few cancer including Acute promyelocyticleukemia and solid tumors. But its effect and possible associated mechanism in HCC is meager. Present study aimed to assess As2O3 modulatory effect on liver cancer by assessing cell growth and viability. METHODS: Liver normal (Chang liver) and cancerous cells (Hep3B) were exposed to different concentration's (0, 1, 5, 10 & 15 µM) of As2O3 at different intervals (24, 48 & 72 h). Cell growth was assessed microscopically, and Cytotoxicity assays were done through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Water-soluble tetrazolium salt (WST) growth inhibition assays. Cell viability was studied by trypan blue staining. Apoptosis was analyzed by Annexin V/PI assay, and expression of genes (Notch and anti-apoptotic) were determined through western blotting and Q-PCR method. KEY FINDINGS: A significant reduction in cell growth and viability was reported in liver cancerous cells as compare to normal cells at 5 µM As2O3. Consistently, As2O3 induced apoptosis along with down-regulation of anti-apoptotic protein Bcl-xL, and up regulates expression of Notch that leads towards apoptosis. SIGNIFICANCE: Results clearly suggest that As2O3 restricted growth and induces apoptosis more in liver cancer cells as compared to normal cells. This finding suggests that it could be a promising potential therapeutic agent against liver cancer which need further testing by in-vivo investigations.

Immunomodulatory Role of Arsenic in Regulatory T Cells.

BACKGROUND AND OBJECTIVE: Chronic Arsenic (As) exposure continued to be a cause of major problem associated with different kind of diseases including skin problem and different types of cancer. As exposure leads to numerous other pathological conditions that affect millions of people worldwide on a regular basis. It was recently established that As toxicity affects immune system and modulates the function and survival of cells involved in immune regulation. Arsenic trioxide (As2O3) was reported to be an effective apoptosis inducer in a variety of cell types. Despite intensive research, the exact immune-modulatory role of As is poorly understood till now. METHODS: We reviewed the immunological imbalance caused due to As exposure and focused on regulatory T cells (Tregs cells). In this review, we mainly focused on role of As and its potential mechanisms in the induction and modulation of Tregs cells. CONCLUSION: The multiple effects of As on immune system tend to decrease the immune surveillance system and increase the rate of infection, autoimmune disease, cancer and other immune mediated problems. As exposed individuals showed induction of oxidative stress, inflammation and impaired lymphocytes activation. The effect of As on T cell population is mainly attributed to altered expression of key immune regulator molecules impaired T cell functions, cytokines production, induction of apoptosis, and oxidative stress induction in T cells.