Antitumor activity of tetrandrine citrate in human glioma U87 cells in vitro and in vivo

Tetrandrine for Targeting Therapy Resistance in Cancer

During the last five decades, there has been tremendous development in our understanding of cancer biology and the development of new and novel therapeutics to target cancer. However, despite these advances, cancer remains the second leading cause of death across the globe. Most cancer deaths are attributed to the development of resistance to current therapies. There is an urgent and unmet need to address cancer therapy resistance. Tetrandrine, a bis-benzyl iso-quinoline, has shown a promising role as an anti-cancer agent. Recent work from our laboratory and others suggests that tetrandrine and its derivatives could be an excellent adjuvant to the current arsenal of anti-cancer drugs. Herein, we provide an overview of resistance mechanisms to current therapeutics and review the existing literature on the anti-cancer effects of tetrandrine and its potential use for overcoming therapy resistance in cancer.

Tetrandrine citrate suppresses lung adenocarcinoma growth via SLC7A11/GPX4-mediated ferroptosis

Ferroptosis is a mode of programmed cell death that plays a crucial role in tumor biology processes. Although tetrandrine citrate (TetC) has been demonstrated to exert anti-tumor effects, it is still unclear whether TetC inhibits lung adenocarcinoma (LUAD) progression by inducing ferroptosis. The study showcased the inhibitory effect of TetC on the viability and progression of tumor cells, including intracellular iron overload, accumulation of reactive oxygen species (ROS), over-expression of malondial-dehyde (MDA), and depletion of glutathione (GSH). Notably, TetC-induced cell death was clearly reversed by three different ferroptosis-related inhibitors. TetC also induced changes in the mitochondrial morphology of LUAD cells, similar to those observed in typical ferroptosis. Further analysis through Western blot (WB) and Immunofluorescence (IF) assays identified that TetC inhibited the expression and fluorescence intensity of both solute carrier family 7 (SLC7A11) and glutathione peroxidase-4 (GPX4). More importantly, over-expression of SLC7A11 could rescue the TetC-induced ferroptosis. Finally, in our vivo experiment, we discovered that TetC significantly slowed the growth rate of subcutaneous transplanted A549 cells, ultimately proving to be biosafe. In conclusion, our study first identified the mechanism by which TetC-induced ferroptosis in LUAD via SLC7A11/GPX4 signaling.

Ultra-small lipid carriers with adjustable release profiles for synergistic treatment of drug-resistant ovarian cancer

Multidrug resistance has dramatically compromised the effectiveness of paclitaxel (PTX). The combined application of PTX and tetrandrine (TET) is a promising avenue in drug-resistant cancer therapy. However, poor drug release and limited intracellular drug accumulation greatly impede this combinational antitumor therapy. To address this problem, we successfully developed a tunable controlled release lipid platform (PT@usNLC) for coordinated drug delivery. The drug release rate of PT@usNLC can be tuned by varying the lipid ratio, which has potential to maximize the therapeutic effects of combined drugs. The TET release rate from PT@usNLC was faster than PTX, which could restore the sensitivity of tumor cells to PTX and exert a synergistic antitumor effect. The appropriate size of PT@usNLC could effectively increase the intracellular drug accumulation. Bothin vitroandin vivostudies revealed that PT@usNLC significantly enhanced the therapeutic effect compared to conventional therapies. This study provides a new strategy for resistant ovarian cancer therapy.

Tetrandrine Suppresses Human Brain Glioblastoma GBM 8401/luc2 Cell-Xenografted Subcutaneous Tumors in Nude Mice In Vivo

Tetrandrine (TET), a bisbenzylisoquinoline (BBI) alkaloid, is isolated from the plant Stephania tetrandra S. Moore and has a wide range of biological activity, including anticancer properties in vitro and in vivo. At first, we established a luciferase-expressing stable clone that was named GBM 8401/luc2 cells. Herein, the primary results indicated that TET reduced the total cell viability and induced cell apoptosis in GBM 8401/luc2 human glioblastoma cells. However, there is no available information showing that TET suppresses glioblastoma cells in vivo. Thus, we investigated the effects and mechanisms of TET on a GBM 8401/luc2 cell-generated tumor in vivo. After the tumor volume reached 100-120 mm³ in subcutaneously xenografted nude mice, all of the mice were randomly divided into three groups: Group I was treated with phosphate-buffered solution (PBS) containing 0.1% dimethyl sulfoxide, Group II with 25 mg/kg of TET, and Group III with 50 mg/kg of TET. All mice were given the oral treatment of PBS or TET by gavage for 21 days, and the body weight and tumor volumes were recorded every 5 days. After treatment, individual tumors, kidneys, livers, and spleens were isolated from each group. The results showed that TET did not affect the body weights, but it significantly decreased the tumor volumes. The TET treatment at 50 mg/kg had a two-fold decrease in tumor volumes than that at 25 mg/kg when compared to the control. TET decreased the total photon flux, and treatment with TET at 50 mg/kg had a lower total photon flux than that at 25 mg/kg, as measured by a Xenogen IVIS imaging system. Moreover, the higher TET treatment had lower tumor volumes and weights than those of the lower dose. The apoptosis-associated protein expression in the tumor section was examined by immunohistochemical analysis, and the results showed that TET treatment reduced the levels of c-FLIP, MCL-1, and XIAP but increased the signals of cleaved-caspase-3, -8, and -9. Furthermore, the hematoxylin and eosin (H & E) staining of kidney, liver, and spleen tissues showed no significant difference between the TET-treated and control groups. Overall, these observations demonstrated that TET suppressed subcutaneous tumor growth in a nude-mice model via the induction of cell apoptosis.

Evaluation of the Anticancer Properties of Geranyl Isovalerate, an Active Ingredient of Argyreia nervosa Extract in Colorectal Cancer Cells

Chemotherapy is a general treatment procedure for cancer. The diversity in cancer incidence and the failure of therapy due to chemoresistance lead to increased cancer-related deaths. Therefore, new drugs with fewer secondary complications targeting diverse pathways are the need of the hour. Geranyl isovalerate (GIV), one of the active ingredients of ethyl acetate fraction of Argyreia nervosa is routinely used as a food flavoring agent. In this study, we found that GIV also exhibits anticancer activity when tested against the HCT116 cell line. It influenced the viability of the cells in a dose- and time-dependent manner. We examined whether GIV could induce oxidative stress and affect the mitochondrial membrane potential, thereby leading to apoptosis induction. Moreover, GIV could suppress the expression of antiapoptotic genes, such as BCl2 and PARP, and induce the expression of proapoptotic genes, such as Caspase 3 and 9. This is the first study demonstrating the anticancer activity of GIV and providing evidence for its mechanism of action. In conclusion, this study proposes GIV as a potential lead or supplementary molecule in treating and preventing colorectal cancer (CRC). Based on our findings, we conclude that GIV may be a viable lead or supplementary molecule for treating and preventing CRC.