JNK and Autophagy Independently Contributed to Cytotoxicity of Arsenite combined With Tetrandrine via Modulating Cell Cycle Progression in Human Breast Cancer Cells

Altered Regulation of the Glucose Transporter GLUT3 in PRDX1 Null Cells Caused Hypersensitivity to Arsenite

Targeting tumour metabolism through glucose transporters is an attractive approach. However, the role these transporters play through interaction with other signalling proteins is not yet defined. The glucose transporter SLC2A3 (GLUT3) is a member of the solute carrier transporter proteins. GLUT3 has a high affinity for D-glucose and regulates glucose uptake in the neurons, as well as other tissues. Herein, we show that GLUT3 is involved in the uptake of arsenite, and its level is regulated by peroxiredoxin 1 (PRDX1). In the absence of PRDX1, GLUT3 mRNA and protein expression levels are low, but they are increased upon arsenite treatment, correlating with an increased uptake of glucose. The downregulation of GLUT3 by siRNA or deletion of the gene by CRISPR cas-9 confers resistance to arsenite. Additionally, the overexpression of GLUT3 sensitises the cells to arsenite. We further show that GLUT3 interacts with PRDX1, and it forms nuclear foci, which are redistributed upon arsenite exposure, as revealed by immunofluorescence analysis. We propose that GLUT3 plays a role in mediating the uptake of arsenite into cells, and its homeostatic and redox states are tightly regulated by PRDX1. As such, GLUT3 and PRDX1 are likely to be novel targets for arsenite-based cancer therapy.

Towards dual function of autophagy in breast cancer: A potent regulator of tumor progression and therapy response

As a devastating disease, breast cancer has been responsible for decrease in life expectancy of females and its morbidity and mortality are high. Breast cancer is the most common tumor in females and its treatment has been based on employment of surgical resection, chemotherapy and radiotherapy. The changes in biological behavior of breast tumor relies on genomic and epigenetic mutations and depletions as well as dysregulation of molecular mechanisms that autophagy is among them. Autophagy function can be oncogenic in increasing tumorigenesis, and when it has pro-death function, it causes reduction in viability of tumor cells. The carcinogenic function of autophagy in breast tumor is an impediment towards effective therapy of patients, as it can cause drug resistance and radio-resistance. The important hallmarks of breast tumor such as glucose metabolism, proliferation, apoptosis and metastasis can be regulated by autophagy. Oncogenic autophagy can inhibit apoptosis, while it promotes stemness of breast tumor. Moreover, autophagy demonstrates interaction with tumor microenvironment components such as macrophages and its level can be regulated by anti-tumor compounds in breast tumor therapy. The reasons of considering autophagy in breast cancer therapy is its pleiotropic function, dual role (pro-survival and pro-death) and crosstalk with important molecular mechanisms such as apoptosis. Moreover, current review provides a pre-clinical and clinical evaluation of autophagy in breast tumor.

Effect of Size and Concentration of Copper Nanoparticles on the Antimicrobial Activity in Escherichia coli through Multiple Mechanisms

Metal and metal oxide nanoparticles, including copper nanoparticles (CuNPs), display antimicrobial activities and are regarded as promising microorganism inhibitors. Here, we explored the antimicrobial activity of CuNPs in Escherichia coli (E. coli) using two particle sizes (20 and 60 nm) and five concentrations (1, 5, 10, 50 and 100 μg/mL). The result showed a concentration-dependent trend of bactericidal activities for both size groups, with 20 nm particles more effective than 60 nm particles at low concentrations. The membrane disruption caused by CuNPs was confirmed by electron microscopy, PI staining and protein leaking analysis. However, the results of reactive oxygen species generation and genomic DNA damage revealed that the size and concentration of CuNPs were factors affecting the induction of multiple bactericidal mechanisms simultaneously on different scales. Further results of annexin V-PI staining supported this hypothesis by showing the shifting composition of the early-, late- and non-apoptotic dead cells across the CuNP groups. Many CuNP treatment groups were rescued when four mammalian modulators-wortmannin, necrosulfonamide, Z-VAD-FMK, and SBI-0206965-were applied separately. The results suggest the possible existence of bacterial programmed cell death pathways in E. coli which could be triggered by CuNP treatments.

Autophagy and cancer: Can tetrandrine be a potent anticancer drug in the near future?

Autophagy is an essential catabolic process in mammalian cells to maintain cellular integrity and viability by degrading the old and damaged cell organelles and other contents with the help of lysosomes. Deregulation in autophagy can be one of the major contributors leading to the continuous cell proliferation and development of tumors. Tetrandrine, a bisbenzylisoquinoline alkaloid known to have potent bioactivities such as anticancer, antimicrobial, anti-inflammatory, antidiabetic, antioxidant, immunosuppressive, cardiovascular, and calcium channel blocking effects. The present review evaluated the effectiveness of tetrandrine in targeting key proteins in the autophagy pathway to induce anticancer effect based on the available literature. An attempt is also made to understand the influence of tetrandrine in regulating autophagy by mTOR dependant and mTOR-independent pathways. In addition, the review also highlights the limitations involved and future perspectives in developing tetrandrine as a chemotherapeutic drug to treat cancer.

Cytotoxic Effects of Hellebrigenin and Arenobufagin Against Human Breast Cancer Cells

Development of new therapeutic strategies for breast cancer is urgently needed due to the sustained emergence of drug resistance, tumor recurrence and metastasis. To gain a novel insight into therapeutic approaches to fight against breast cancer, the cytocidal effects of hellebrigenin (Helle) and arenobufagin (Areno) were investigated in human estrogen receptor (ER)-positive breast cancer cell line MCF-7 and triple-negative breast cancer cell line MDA-MB-231. Helle exhibited more potent cytotoxicity than Areno in both cancer cells, and MCF-7 cells were more susceptible to both drugs in comparison with MDA-MB-231 cells. Apoptotic-like morphological characteristics, along with the downregulation of the expression level of Bcl-2 and Bcl-xL and the upregulation of the expression level of Bad, were observed in Helle-treated MCF-7 cells. Helle also caused the activation of caspase-8, caspase-9, along with the cleavage of poly(ADP-ribose) polymerase in MCF-7 cells. Helle-mediated necrosis-like phenotype, as evidenced by the increased propidium iodide (PI)-positive cells was further observed. G₂/M cell cycle arrest was also induced by Helle in the cells. Upregulation of the expression level of p21 and downregulation of the expression level of cyclin D1, cyclin E1, cdc25C and survivin were observed in MCF-7 cells treated with Helle and occurred in parallel with G₂/M arrest. Autophagy was triggered in MCF-7 cells and the addition of wortmannin or 3-MA, two well-known autophagy inhibitors, slightly but significantly rescued the cells. Furthermore, similar alterations of some key molecules associated with the aforementioned biological phenomena were observed in MDA-MB-231 cells. Intriguingly, the numbers of PI-positive cells in Helle-treated MCF-7 cells were significantly reduced by wortmannin and 3-MA, respectively. In addition, Helle-triggered G₂/M arrest was significantly corrected by wortmannin, suggesting autophagy induction contributed to Helle-induced cytotoxicity of breast cancer cells by modulating necrosis and cell cycle arrest. Collectively, our results suggested potential usefulness of both Helle and Areno in developing therapeutic strategies to treat patients with different types of breast cancer, especially ER-positive breast cancer.

A review of chemistry and pharmacology of Piperidine alkaloids of Pinus and related genera

BACKGROUND

Pinus and other related conifers belonging to family pinaceae are most commonly used medicinal plants in Indian North-western Himalayas. Various parts of these plants including needles are source of several well known alkaloids. Of all the alkaloids, piperidine group is one of important component and hold considerable medicinal importance.

METHODS

The group of alkaloids was initially identified from genus Piper through which a large variety of piperidine molecules have been extracted. The planar structure of this heterocyclic nucleus enables acetamide groups to be added at various ring configurations.

RESULTS

In the area of drug research, the piperidine heterocycle has gained considerable interest. To produce a new therapeutic profile, the broad range of its therapeutic application paved the way for researchers to implant the nucleus from time to time in diversified pharmacophores.

DISCUSSION

However, biological functions of piperidine metabolites have been mostly examined on a limited scale and that most of the findings are thus preliminary. We have tried to present different clinical applications of piperidine alkaloids in this study that researchers have already attempted to demystify from time to time.

CONCLUSION

Given the importance of the piperidine nucleus, the study will enable the researcher to produce scaffolds of the highest therapeutic efficacy. We have also illustrated different types of piperidine, its sources in different member of family pinaceae with special emphasis on Pinus.

Mechanism of Tetrandrine Against Endometrial Cancer Based on Network Pharmacology

Background

Endometrial cancer (EC) is one of the most common gynaecological malignancies, and its incidence has been rising over the past decade. Tetrandrine, a bisbenzylisoquinoline alkaloid, has been isolated from a vine used in traditional Chinese medicine, Stephania tetrandra. However, the key mechanism of tetrandrine in EC is still unclear.

Purpose

This research was designed to predict the molecular mechanisms of tetrandrine against EC based on network pharmacology and to further verify these predictions by in vitro experiments.

Methods

The potential therapeutic targets of tetrandrine against EC were predicted by using public databases. Afterwards, the protein–protein interaction (PPI) network of the common targets was constructed, and the key gene targets were obtained. Biological function and pathway enrichment analyses were performed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Furthermore, molecular docking and in vitro experiments were carried out to verify the predictions. The cell counting kit‑8 (CCK‑8) assay, Hoechst 33258 staining, flow cytometry analysis, qRT-PCR, Western blot analysis and an immunofluorescence assay were performed.

Results

Our findings identified 111 potential therapeutic targets of tetrandrine against EC. We obtained 7 key gene targets from the PPI network analysis. Furthermore, GO enrichment analysis indicated that these targets were mainly associated with metabolic processes, responses to stimulus, and biological regulation. The KEGG pathway analysis showed that the common targets were mainly distributed in the PI3K/Akt signalling pathway. A potential interaction of tetrandrine with Akt1 was revealed by molecular docking. In addition, in vitro experiments showed that tetrandrine significantly inhibited cell proliferation and induced apoptosis in Ishikawa and HEC-1-B cells in dose- and time-dependent manners. The results also revealed that tetrandrine can downregulate the expression of Bcl-2 and upregulate the expression of Bax at the mRNA level. The mRNA levels of Akt were not significantly different in the various tetrandrine (0, 10 and 20µM) groups. However, Western blot analysis demonstrated that the protein expression ratios of p-Akt/Akt decreased at the protein level. The results were further confirmed by immunofluorescence assays.

Conclusion

Based on bioinformatic analysis and experimental verification, our findings demonstrated that tetrandrine exerted tumour-suppressive effects on EC by regulating the PI3K/Akt signalling pathway.

Cytotoxic Effects of Arsenite in Combination With Gamabufotalin Against Human Glioblastoma Cell Lines

Glioblastoma is a fatal primary malignant brain tumor, and the 5-year survival rate of treated glioblastoma patients still remains <5%. Considering the sustained development of metastasis, tumor recurrence, and drug resistance, there is an urgent need for the novel therapeutic approaches to combat glioblastoma. Trivalent arsenic derivative (arsenite, As^III) with remarkable clinical efficacy in leukemia has been shown to exert cytocidal effect against glioblastoma cells. Gamabufotalin, an active bufadienolide compound, also shows selective cytocidal effect against glioblastoma cells, and has been suggested to serve as a promising adjuvant therapeutic agent to potentiate therapeutic effect of conventional anticancer drugs. In order to gain novel insight into therapeutic approaches against glioblastoma, the cytotoxicity of As^III and gamabufotalin was explored in the human glioblastoma cell lines U-87 and U-251. In comparison with U-251 cells, U-87 cells were highly susceptible to the two drugs, alone or in combination. More importantly, clinically achieved concentrations of As^III combined with gamabufotalin exhibited synergistic cytotoxicity against U-87 cells, whereas showed much less cytotoxicity to human normal peripheral blood mononuclear cells. G₂/M cell cycle arrest was induced by each single drug, and further augmented by their combination in U-87 cells. Downregulation of the expression levels of cdc25C, Cyclin B1, cdc2, and survivin was observed in U-87 cells treated with the combined regimen and occurred in parallel with G₂/M arrest. Concomitantly, lactate dehydrogenase leakage was also observed. Intriguingly, SB203580, a specific inhibitor of p38 MAPK, intensified the cytotoxicity of the combined regimen in U-87 cells, whereas wortmannin, a potent autophagy inhibitor, significantly rescued the cells. Collectively, G₂/M arrest, necrosis and autophagy appeared to cooperatively contribute to the synergistic cytotoxicity of As^III and gamabufotalin. Given that p38 MAPK serves an essential role in promoting glioblastoma cell survival, developing a possible strategy composed of As^III, gamabufotalin, and a p38 MAPK inhibitor may provide novel insight into approaches designed to combat glioblastoma.

Natural product derived phytochemicals in managing acute lung injury by multiple mechanisms

Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS) as common life-threatening lung diseases with high mortality rates are mostly associated with acute and severe inflammation in lungs. With increasing in-depth studies of ALI/ARDS, significant breakthroughs have been made, however, there are still no effective pharmacological therapies for treatment of ALI/ARDS. Especially, the novel coronavirus pneumonia (COVID-19) is ravaging the globe, and causes severe respiratory distress syndrome. Therefore, developing new drugs for therapy of ALI/ARDS is in great demand, which might also be helpful for treatment of COVID-19. Natural compounds have always inspired drug development, and numerous natural products have shown potential therapeutic effects on ALI/ARDS. Therefore, this review focuses on the potential therapeutic effects of natural compounds on ALI and the underlying mechanisms. Overall, the review discusses 159 compounds and summarizes more than 400 references to present the protective effects of natural compounds against ALI and the underlying mechanism.