Arsenic Inhibits Proliferation and Induces Autophagy of Tumor Cells in Pleural Effusion of Patients with Non-Small Cell Lung Cancer Expressing EGFR with or without Mutations via PI3K/AKT/mTOR Pathway

Autophagy plays a pro-apoptotic role in arsenic trioxide-induced cell death of liver cancer

OBJECTIVE

The effects of arsenic trioxide (As2O3) on hepatocellular carcinoma have been documented widely. Autophagy plays dual roles in the survival and death of cancer cells. Therefore, we investigated the exact role of autophagy in As2O3-induced apoptosis in liver cancer cells.

METHODS

The viability of hepatoma cells was determined using the MTT assay with or without fetal bovine serum. The rate of apoptosis in liver cancer cells treated with As2O3 was evaluated using flow cytometry, Hoechst 33258 staining, and TUNEL assays. The rate of autophagy among liver cancer cells treated with As2O3 was detected using immunofluorescence, Western blot assay and transmission electron microscopy.

RESULTS

Upon treatment with As2O3, the viability of HepG2 and SMMC-7721 cells was decreased in a time- and dose-dependent manner. The apoptosis rates of both liver cancer cell lines increased with the concentration of As2O3, as shown by flow cytometry. Apoptosis in liver cancer cells treated with As2O3 was also shown by the activation of the caspase cascade and the regulation of Bcl-2/Bax expression. Furthermore, As2O3 treatment induced autophagy in liver cancer cells; this finding was supported by Western blot, immunofluorescence of LC3-II and beclin 1, and transmission electron microscopy. In liver cancer cells, As2O3 inhibited the phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signal pathway that plays a vital role in both apoptosis and autophagy. The PI3K activator SC-79 partially reversed As2O3-induced autophagy and apoptosis. Furthermore, inhibiting autophagy with 3-methyladenine partially reversed the negative effects of As2O3 on cell viability. Serum starvation increased autophagy and amplified the effect of As2O3 on cell death.

CONCLUSION

As2O3 induces apoptosis and autophagy in liver cancer cells. Autophagy induced by As2O3 may have a proapoptotic effect that helps to reduce the viability of liver cancer cells. This study provides novel insights into the effects of As2O3 against liver cancer. Please cite this article as: Deng ZT, Liang SF, Huang GK, Wang YQ, Tu XY, Zhang YN, Li S, Liu T, Cheng BB. Autophagy plays a pro-apoptotic role in arsenic trioxide-induced cell death of liver cancer. J Integr Med. 2024; 22(3): 295-302.

Arsenic trioxide: applications, mechanisms of action, toxicity and rescue strategies to date

Arsenical medicine has obtained its status in traditional Chinese medicine for more than 2,000 years. In the 1970s, arsenic trioxide was identified to have high efficacy and potency for the treatment of acute promyelocytic leukemia, which promoted many studies on the therapeutic effects of arsenic trioxide. Currently, arsenic trioxide is widely used to treat acute promyelocytic leukemia and various solid tumors through various mechanisms of action in clinical practice; however, it is accompanied by a series of adverse reactions, especially cardiac toxicity. This review presents a comprehensive overview of arsenic trioxide from preclinical and clinical efficacy, potential mechanisms of action, toxicities, and rescue strategies for toxicities to provide guidance or assistance for the clinical application of arsenic trioxide.

Salvianolic acid A attenuates arsenic-induced ferroptosis and kidney injury via HIF-2α/DUOX1/GPX4 and iron homeostasis

Arsenic (As) is a prevalent pollutant in the environment and causes a high frequency of kidney disease in areas of high arsenic contamination, but its pathogenic mechanisms have yet to be completely clarified. Ferroptosis is a new form of cell death mainly dependent on lipid peroxidation and iron accumulation. Several reports have suggested that ferroptosis is operative in a spectrum of diseases caused by arsenic exposure, including in the lungs, pancreas, and testis. However, the mechanism and exact role of ferroptosis in arsenic-induced kidney injury is not known. Firstly, by constructing in vivo and in vitro arsenic exposure models, we confirmed the occurrence of ferroptosis based on the identification of the ability of NaASO2 to cause kidney injury. In addition, we found that arsenic exposure could upregulate DUOX1 expression in kidney and HK-2 cells, and after knocking down DUOX1 using siRNA was able to significantly upregulate GPX4 expression and attenuate ferroptosis. Subsequently using bioinformatics, we identified and proved the involvement of HIF-2α in the course of ferroptosis, and further confirmed by dual luciferase assay that HIF-2α promotes DUOX1 transcription to increase its expression. Finally, intervention with the natural ingredient SAA significantly attenuated arsenic-induced ferroptosis and kidney injury. These results showed that arsenic could cause ferroptosis and kidney injury by affecting HIF-2α/DUOX1/GPX4 and iron homeostasis and that SAA was an effective intervention component. This study not only discovered the molecular mechanism of sodium arsenite-induced kidney injury but also explored an active ingredient with intervention potential, providing a scientific basis for the prevention and treatment of sodium arsenite-induced kidney injury.

Arsenic Trioxide Suppresses Angiogenesis in Non-small Cell Lung Cancer via the Nrf2-IL-33 Signaling Pathway

BACKGROUND

Non-Small Cell Lung Cancer (NSCLC) ranks as a leading cause of cancer-related mortality, necessitating the urgent search for cost-effective and efficient anti-NSCLC drugs. Our preliminary research has demonstrated that arsenic trioxide (ATO) significantly inhibits NSCLC angiogenesis, exerting anti-tumor effects. In conjunction with existing literature reports, the Nrf2-IL-33 pathway is emerging as a novel mechanism in NSCLC angiogenesis.

OBJECTIVE

This study aimed to elucidate whether ATO can inhibit NSCLC angiogenesis through the Nrf2-IL-33 pathway.

METHODS

Immunohistochemistry was employed to assess the expression of Nrf2, IL-33, and CD31 in tumor tissues from patients with NSCLC. DETA-NONOate was used as a nitric oxide (NO) donor to mimic high levels of NO in the tumor microenvironment. Western blot, quantitative real-time PCR, and enzyme-linked immunosorbent assay were utilized to evaluate the expression of Nrf2 and IL-33 in the NCI-H1299 cell line. Subcutaneous xenograft models were established in nude mice by implanting NCI-H1299 cells to assess the anti-tumor efficacy of ATO.

RESULTS

High expression levels of Nrf2 and IL-33 were observed in tumor samples from patients with NSCLC, and Nrf2 expression positively correlated with microvascular density in NSCLC. In vitro, NO (released from 1mM DETA-NONOate) promoted activation of the Nrf2-IL-33 signaling pathway in NCI-H1299 cells, which was reversed by ATO. Additionally, both Nrf2 deficiency and ATO treatment significantly attenuated NOinduced IL-33 expression. In vivo, both ATO and the Nrf2 inhibitor ML385 demonstrated significant inhibitory effects on angiogenesis tumor growth.

CONCLUSION

Nrf2-IL-33 signaling is usually activated in NSCLC and positively correlates with tumor angiogenesis. ATO effectively disrupts the activation of the Nrf2-IL-33 pathway in NSCLC and thus inhibits angiogenesis, suggesting its potential as an anti-angiogenic agent for use in the treatment of NSCLC.

Open a new epoch of arsenic trioxide investigation: ATOdb

Arsenic trioxide (ATO) is a great discovery in the treatment of acute promyelocytic leukemia (APL), which has been used in an increasing number of malignant diseases. Systematic integrative analysis will help to precisely understand the mechanism of ATO and find new combined drugs. Therefore, we developed a one-stop comprehensive database of ATO named ATOdb by manually compiling a wealth of experimentally supported ATO-related data from 3479 articles, and integrated analysis tools. The current version of ATOdb contains 8373 associations among 2300 ATO targets, 80 conditions and 262 combined drugs. Each entry in ATOdb contains detailed information on ATO targets, therapeutic/side effects, systems, cell names, cell types, regulations, detection methods, brief descriptions, references, etc. Furthermore, ATOdb also provides data visualization and analysis results such as the drug similarities, protein-protein interactions, and miRNA-mRNA relationships. An easy-to-use web interface was deployed in ATOdb for users to easily browse, search and download the data. In conclusion, ATOdb will serve as a valuable resource for in-depth study of the mechanism of ATO, discovery of new drug combination strategies, promotion of rational drug use and individualized treatments. ATOdb is freely available at http://bio-bigdata.hrbmu.edu.cn/ATOdb/index.jsp.

Implication of mTOR Signaling in NSCLC: Mechanisms and Therapeutic Perspectives

Mechanistic target of the rapamycin (mTOR) signaling pathway represents a central cellular kinase that controls cell survival and metabolism. Increased mTOR activation, along with upregulation of respective upstream and downstream signaling components, have been established as oncogenic features in cancer cells in various tumor types. Nevertheless, mTOR pathway therapeutic targeting has been proven to be quite challenging in various clinical settings. Non-small cell lung cancer (NSCLC) is a frequent type of solid tumor in both genders, where aberrant regulation of the mTOR pathway contributes to the development of oncogenesis, apoptosis resistance, angiogenesis, cancer progression, and metastasis. In this context, the outcome of mTOR pathway targeting in clinical trials still demonstrates unsatisfactory results. Herewith, we discuss recent findings regarding the mechanisms and therapeutic targeting of mTOR signaling networks in NSCLC, as well as future perspectives for the efficient application of treatments against mTOR and related protein molecules.