A novel derivative of tetrandrine (H1) induces endoplasmic reticulum stress-mediated apoptosis and prosurvival autophagy in human non-small cell lung cancer cells

A Comprehensive Appraisal of Bisbenzylisoquinoline Alkaloids Isolated From Genus Cyclea for Anticancer Potential

The pharmaceutical industry and academia are continuously searching for novel and effective anticancer lead compounds to ensure patient safety, provide a cure, and surpass all other obstacles. Given the indeterminate nature of cancer etiology, the importance of drugs capable of targeting multiple pathways cannot be overstated. Among naturally occurring compounds, bisbenzylisoquinoline (BBIQ) alkaloids, such as berberine, tetrandrine, chelidonine, and berbamine, have demonstrated significant anticancer potential by modulating diverse signaling pathways. Several of these compounds are currently in clinical trials, highlighting their relevance in cancer treatment. This review emphasizes the need for further investigation into the anticancer properties of BBIQ alkaloids, particularly those isolated from eight Cyclea species in India. With around 27 BBIQ alkaloids identified, these compounds hold promise, especially in combating multidrug resistance-a critical challenge in cancer therapy. Given the rising cancer incidence, these alkaloids warrant a deeper exploration of their therapeutic potential.

Understanding the molecular regulatory mechanisms of autophagy in lung disease pathogenesis

Lung disease development involves multiple cellular processes, including inflammation, cell death, and proliferation. Research increasingly indicates that autophagy and its regulatory proteins can influence inflammation, programmed cell death, cell proliferation, and innate immune responses. Autophagy plays a vital role in the maintenance of homeostasis and the adaptation of eukaryotic cells to stress by enabling the chelation, transport, and degradation of subcellular components, including proteins and organelles. This process is essential for sustaining cellular balance and ensuring the health of the mitochondrial population. Recent studies have begun to explore the connection between autophagy and the development of different lung diseases. This article reviews the latest findings on the molecular regulatory mechanisms of autophagy in lung diseases, with an emphasis on potential targeted therapies for autophagy.

Isoquinolines alkaloids and cancer metabolism: Pathways and targets to novel chemotherapy

Cancer is one of the main causes of death in the world. This is a complex disease where the development of resistance to chemotherapy is frequent driving the search for new anticancer compounds. In this sense, isoquinolines have gained attention in the past few years. This review aims to highlight the new advances related to the use of isoquinolines compounds against cancer cells, and we point out targets for their anti-tumor action. Isoquinolines are compounds found in plants that are important for their protection. In cancer, many representatives of this class of compounds have demonstrated their efficacy against cancer by acting on cancer metabolism, such as triggering cell death, reducing pro-survival protein expression, inducing ROS production, inhibiting pro-survival cell signaling pathways, among other effects. The mechanisms triggered by isoquinolines in cancer cells represent robust anticancer strategies, which support that this class of compounds are strong candidates for cancer treatment.

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.

Targeting the two-pore channel 2 in cancer progression and metastasis

The importance of Ca²⁺ signaling, and particularly Ca²⁺ channels, in key events of cancer cell function such as proliferation, metastasis, autophagy and angiogenesis, has recently begun to be appreciated. Of particular note are two-pore channels (TPCs), a group of recently identified Ca²⁺-channels, located within the endolysosomal system. TPC2 has recently emerged as an intracellular ion channel of significant pathophysiological relevance, specifically in cancer, and interest in its role as an anti-cancer drug target has begun to be explored. Herein, an overview of the cancer-related functions of TPC2 and a discussion of its potential as a target for therapeutic intervention, including a summary of clinical trials examining the TPC2 inhibitors, naringenin, tetrandrine, and verapamil for the treatment of various cancers is provided.

An overview on the chemistry, pharmacology and anticancer properties of tetrandrine and fangchinoline (alkaloids) from Stephania tetrandra roots

Tetrandrine (TET) and fangchinoline (FAN) are dominant bisbenzylisoquinoline (BBIQ) alkaloids from the roots of Stephania tetrandra of the family Menispermaceae. BBIQ alkaloids comprise two benzylisoquinoline units linked by oxygen bridges. The molecular structures of TET and FAN are exactly the same, except that TET has a methoxy (-OCH₃) group, while FAN has a hydroxyl (-OH) group at C7. In this overview, the current knowledge on the chemistry, pharmacology and anticancer properties of TET and FAN have been updated. The focus is on colon and breast cancer cells, because they are most susceptible to TET and FAN, respectively. Against colon cancer cells, TET inhibits cell proliferation and tumor growth by inducing apoptosis and G1 cell cycle arrest, and suppresses adhesion, migration and invasion of cells. Against breast cancer cells, FAN inhibits cell proliferation by inducing apoptosis, G1-phase cell cycle arrest and inhibits cell migration. The processes involve various molecular mechanisms and signaling pathways. Some insights on the ability of TET and FAN to reverse multi-drug resistance in cancer cells and suggestions for future research are provided.

Long non-coding RNA CASC2 enhances irradiation-induced endoplasmic reticulum stress in NSCLC cells through PERK signaling

Radiotherapy is instrumental in the treatment of inoperable non-small cell lung cancer (NSCLC). Studies have revealed that radiotherapy induces endoplasmic reticulum (ER) stress, which consequently induces apoptosis and sensitization of cancer cells. A recent study has revealed that long non-coding RNA (lncRNA) CASC2 is negatively correlated with the malignancy of NSCLC cells. The present study investigated the effects and molecular mechanisms of CASC2 on radiosensitivity and ER stress in NSCLC cells. The overexpression of CASC2 markedly decreased cell survival and increased apoptosis, expression of PERK, phosphorylated-eIF2α and CHOP in irradiated human NSCLC cells, whereas knocking down PERK reversed these effects. Moreover, CASC2 considerably promoted the stability of PERK mRNA, but had no effect on the activity of PERK gene promoter in irradiated NSCLC cells. Strikingly, CASC2 exhibited no apparent effect on non-irradiated NSCLC cells. This study demonstrated that lncRNA CASC2 increases the stability of PERK mRNA, which consequently triggers the PERK/eIF2α/CHOP ER stress pathway and promotes radiosensitivity or apoptosis in irradiated NSCLC cells. Results of the present study suggest that CASC2 can act as an effective therapeutic target to enhance the efficacy of radiotherapy in the treatment of NSCLC.

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

Novel therapeutic strategies for breast cancer are urgently needed due to the sustained development of drug resistance and tumor recurrence. Trivalent arsenic derivative (arsenite, As^III) has been reported to induce cytotoxicity in breast cancer cells. We recently demonstrated that As^III plus tetrandrine (Tetra), a Chinese plant-derived alkaloid, exerted potent antitumor activity against human breast cancer cells, however, the underlying mechanisms for their action have not been well defined. In order to provide fundamental insights for understanding the action of As^III plus Tetra, the effects of the combined regimen on two breast cancer cell lines T47D and MDA-MB-231 were evaluated. Compared to T47D cells, MDA-MB-231 cells were much more susceptible to the synergistic cytotoxic effects of As^III and Tetra. Besides the induction of apoptotic/necrotic cell death, S-phase arrest and autophagic cell death were also observed in MDA-MB-231 cells. Exposure of MDA-MB-231 cells to As^III and Tetra caused the activation of MAPKs. Cytotoxicity of the combined regimen in MDA-MB-231 cell was significantly abrogated by SP600125, a potent c-Jun N-terminal kinase (JNK) inhibitor. However, similar abrogation was not caused by p38 and ERK inhibitors. The addition of either autophagy inhibitors (3-methyladenine or wortmannin) or SP600125 corrected the combined regimen-triggered S-phase arrest, whereas had little effect on the apoptosis/necrosis induction in the cells. Surprisingly, SP600125NC, a negative control for SP600125, significantly strengthened S-phase arrest and the cytotoxicity induced by the combined regimen. The addition of SP600125 did not alter autophagy induction. In conclusion, the cytotoxicity of As^III combined with Tetra was attributed to the induction of S-phase arrest, apoptotic/necrotic and autophagic cell death. The enhanced cytotoxicity of the two drugs by SP600125NC might be explained by its capability to strengthen S-phase arrest. Our results suggested that JNK and autophagy independently contributed to the cytotoxicity via modulating cell cycle progression. The study further provides fundamental insights for the development of As^III in combination with Tetra for patients with different types of breast cancer.

Synthesis, purification, and anticancer effect of magnetic Fe3O4-loaded poly (lactic-co-glycolic) nanoparticles of the natural drug tetrandrine

Here, we have successfully synthesised and purified multifunctional PLGA-based nanoparticles by the co-encapsulation of an anticancer drug (tetrandrine) and a magnetic material (Fe₃O₄). The obtained Tet-Fe₃O₄-PLGA NPs had a uniform spherical shape with a particle size of approximately 199 nm and a negative surface charge of -18.0 mV, displaying a high encapsulation efficiency. Furthermore, TEM studies provided representative images of the purification process of the magnetic nanoparticles with MACS^® technology. The MFM and VSM results indicated that both the Fe₃O₄ NPs and Tet-Fe₃O₄-PLGA NPs were superparamagnetic. The DSC spectrum demonstrated that Tet was successfully encapsulated within the PLGA-based nanoparticles. Significantly, the release studies revealed NPs had a relatively slower release rate than free Tet after 8 h's initial burst release, which had decreased from 98% to 65% after 24 h. In vitro cellular studies revealed that NPs could effectively penetrate into A549 cells and A549 multicellular spheroids to exert cytotoxicity, displaying a significantly high anti-proliferation effect. Moreover, western blot demonstrated that the co-loaded NPs had a higher anticancer activity by injuring lysosomes to activate the mitochondria pathway and induce A549 cell apoptosis. The magnetic characteristics and high anticancer activity support the use of Tet/Fe₃O₄ co-loaded PLGA-based nanoparticles as a promising strategy in the treatment of lung cancer.

Alkaloids for cancer prevention and therapy: Current progress and future perspectives

Alkaloids are important chemical compounds that serve as a rich source for drug discovery. Numerous alkaloids screened from medicinal plants and herbs showed antiproliferative and anticancer effects on wide category of cancers both in vitro and in vivo. Vinblastine, vinorelbine, vincristine, and vindesine have already been successfully developed as anticancer drugs. The available and up-to-date information on the ethnopharmacological uses in traditional medicine, phytochemistry, pharmacology and clinical utility of alkaloids were collected using various resources (PubMed, ScienceDirect, Google Scholar and Springerlink). In this article, we provide a comprehensive and critical overview on naturally-occurring alkaloids with anticancer activities and highlight the molecular mechanisms of action of these secondary metabolites. Furthermore, this review also presents a summary of synthetic derivatives and pharmacological profiles useful to researchers for the therapeutic development of alkaloids. Based on the literature survey compiled in this review, alkaloids represent an important group of anticancer drugs of plant origin with enormous potential for future development of drugs for cancer therapy and management.

Targeting the unfolded protein response in head and neck and oral cavity cancers

Many FDA-approved anti-cancer therapies, targeted toward a wide array of molecular targets and signaling networks, have been demonstrated to activate the unfolded protein response (UPR). Despite a critical role for UPR signaling in the apoptotic execution of cancer cells by many of these compounds, the authors are currently unaware of any instance whereby a cancer drug was developed with the UPR as the intended target. With the essential role of the UPR as a driving force in the genesis and maintenance of the malignant phenotype, a great number of pre-clinical studies have surged into the medical literature describing the ability of dozens of compounds to induce UPR signaling in a myriad of cancer models. The focus of the current work is to review the literature and explore the role of the UPR as a mediator of chemotherapy-induced cell death in squamous cell carcinomas of the head and neck (HNSCC) and oral cavity (OCSCC), with an emphasis on preclinical studies.

High Performance Liquid Chromatography Determination and Optimization of the Extraction Process for the Total Alkaloids from Traditional Herb Stephania cepharantha Hayata

Stephania cepharantha Hayata is a traditional Chinese herbal medicine used to treat lung cancer, and its alkaloids, especially cepharanthine (CEP), were reported to be its effective ingredients. Therefore, the extraction of potential antitumor ingredients from the plant was of interest. We first explored the optimized solvent extraction of antitumor agents from S. cepharantha Hayata guided by an in vitro antitumor activity assay. The solvent for extraction and its concentration, the liquid to material ratio, extraction duration, particle size, macerating time, and the frequency of extraction were investigated using a single-factor experiment. An orthogonal design (L9, 3⁴) was constructed to determine the suitable extraction conditions. The crude extract was then purified sequentially by macroporous adsorption resins (MR) for the enrichment of CEP. Under these optimal conditions, the yield of total alkaloids in the herbs was 3.4%, whereas the CEP content was 2.9%. Total alkaloids exhibited significant anti-proliferative activities in the A549 cell line. Our study provides means for the further development and use of the antitumor components from S. cepharantha, which has potential for application in the pharmaceutical industry.

Tetrandrine, a Chinese plant-derived alkaloid, is a potential candidate for cancer chemotherapy

Cancer is a disease caused by the abnormal proliferation and differentiation of cells governed by tumorigenic factors. Chemotherapy is one of the major cancer treatment strategies, and it functions by targeting the physiological capabilities of cancer cells, including sustained proliferation and angiogenesis, the evasion of programmed cell death, tissue invasion and metastasis. Remarkably, natural products have garnered increased attention in the chemotherapy drug discovery field because they are biologically friendly and have high therapeutic effects. Tetrandrine, isolated from the root of Stephania tetrandra S Moore, is a traditional Chinese clinical agent for silicosis, autoimmune disorders, inflammatory pulmonary diseases, cardiovascular diseases and hypertension. Recently, the novel anti-tumor effects of tetrandrine have been widely investigated. More impressive is that tetrandrine affects multiple biological activities of cancer cells, including the inhibition of proliferation, angiogenesis, migration, and invasion; the induction of apoptosis and autophagy; the reversal of multidrug resistance (MDR); and the enhancement of radiation sensitization. This review focuses on introducing the latest information about the anti-tumor effects of tetrandrine on various cancers and its underlying mechanism. Moreover, we discuss the nanoparticle delivery system being developed for tetrandrine and the anti-tumor effects of other bisbenzylisoquinoline alkaloid derivatives on cancer cells. All current evidence demonstrates that tetrandrine is a promising candidate as a cancer chemotherapeutic.

Tetrandrine and cancer - An overview on the molecular approach

Tetrandrine has been known in the treatment of tuberculosis, hyperglycemia, negative ionotropic and chronotropic effects on myocardium, malaria, cancer and fever since years together. It has been known that, tetrandrine could modulate multiple signaling molecules such as kinases of cell cycle and rat sarcoma (RAS) pathway along with proteins of tumor suppressor genes, autophagy related, β-catenins, caspases, and death receptors. Moreover, tetrandrine exhibited reversal of drug resistance by modulating P-glyco protein (P-gp) expression levels in different cancers which is an added advantage of this compound compared to other chemotherapy drugs. Though, bioavailability of tetrandrine is a limiting factor, the anticancer activity was observed in animal models without changing any pharmacokinetic parameters. In the present review, role of tetrandrine as kinase inhibitor, inducer of autophagy and caspase pathways and suppressor of RAS mediated cell proliferation were discussed along with inhibition of angiogenesis. It has also been discussed that how tetrandrine potentiate anticancer effect in different types of cancers by modulating multidrug resistance under in vitro and in vivo trials including the available literature on the clinical trials.

Tetrandrine Exerts a Radiosensitization Effect on Human Glioma through Inhibiting Proliferation by Attenuating ERK Phosphorylation

Tetrandrine (Tet), a bisbenzylisoquinoline alkaloid, has been reported to have a radiosensitization effect on tumors. However, its effects on human glioma and the specific molecular mechanisms of these effects remain unknown. In this study, we demonstrated that Tet has a radiosensitization effect on human glioma cells. It has been hypothesized that Tet has a radiosensitization effect on glioma cells by affecting the glioma cell cycle and DNA repair mechanism and that ERK mediates these activities. Therefore, we conducted detailed analyses of the effects of Tet on the cell cycle by performing flow cytometric analysis and on DNA repair by detecting the expression of phosphorylated H2AX by immunofluorescence. We used western blot analysis to investigate the role of ERK in the effect of Tet on the cell cycle and DNA repair. The results revealed that Tet exerts its radiosensitization effect on glioma cells by inhibiting proliferation and decreasing the expression of phosphorylated ERK and its downstream proteins. In summary, our data indicate that ERK is involved in Tet-induced radiosensitization of glioma cells via inhibition of glioma cell proliferation or of the cell cycle at G0/G1 phase.

TGF-β1/PTEN/PI3K signaling plays a critical role in the anti-proliferation effect of tetrandrine in human colon cancer cells

The diagnosis and treatment for colon cancer have been greatly developed, but the prognosis remains unsatisfactory. There is still a great clinical need to explore new efficacious drugs for colon cancer treatment. Tetrandrine (Tet) is a bis-benzylisoquinoline alkaloid. It has been shown that Tet may be a potential candidate for cancer treatment, but the explicit mechanism underlying this activity remains unclear. In this study, we investigated the anticancer activity of Tet in human colon cancer cells and dissected the possible mechanism. With cell viability assay and flow cytometry analysis, we confirmed that Tet can effectively inhibit the proliferation and induce apoptosis in HCT116 cells. Mechanically, we found that Tet greatly increases the mRNA and protein level of TGF-β1 in HCT116 cells. Exogenous TGF-β1 enhances the anti-proliferation and apoptosis inducing effect of Tet in HCT116 cells, which has been partly reversed by TGF-β1 inhibitor. Tet decreases the phosphorylation of Akt1/2/3 in HCT116 cells. This effect can be enhanced by exogenous TGF-β1, but partly reversed by TGF-β1 inhibitor. Tet exhibits no effect on total level of PTEN, but decreases the phosphorylation of PTEN; exogenous TGF-β1 enhances the effect of Tet on decreasing the phosphorylation of PTEN, which was partly reversed by TGF-β1 inhibitor. Our findings suggested that Tet may be a promising candidate for colon cancer treatment, and the anticancer activity may be mediated by inactivating PI3K/Akt signaling through upregulating TGF-β1 to decrease the phosphorylation of PTEN.

Role of Autophagy and Apoptosis in Non-Small-Cell Lung Cancer

Non-small-cell lung cancer (NSCLC) constitutes 85% of all lung cancers, and is the leading cause of cancer-related death worldwide. The poor prognosis and resistance to both radiation and chemotherapy warrant further investigation into the molecular mechanisms of NSCLC and the development of new, more efficacious therapeutics. The processes of autophagy and apoptosis, which induce degradation of proteins and organelles or cell death upon cellular stress, are crucial in the pathophysiology of NSCLC. The close interplay between autophagy and apoptosis through shared signaling pathways complicates our understanding of how NSCLC pathophysiology is regulated. The apoptotic effect of autophagy is controversial as both inhibitory and stimulatory effects have been reported in NSCLC. In addition, crosstalk of proteins regulating both autophagy and apoptosis exists. Here, we review the recent advances of the relationship between autophagy and apoptosis in NSCLC, aiming to provide few insights into the discovery of novel pathogenic factors and the development of new cancer therapeutics.

Tetrandrine Induces Apoptosis of Human Nasopharyngeal Carcinoma NPC-TW 076 Cells through Reactive Oxygen Species Accompanied by an Endoplasmic Reticulum Stress Signaling Pathway

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy of the head and neck and the incidence is higher in Southeast Asia. Tetrandrine (TET) is a bisbenzylisoquinoline alkaloid, a natural product, and exhibits biological activities including action against many human cancer cell lines. However, the molecular mechanism of TET-induced cell apoptosis in human NPC cells is still unclear. In the present study, we investigated TET-induced apoptotic cell death and associated possible signal pathways on human nasopharyngeal carcinoma NPC-TW 076 cells in vitro. Phase contrast microscopy was used to examine cell morphology and DAPI staining was used to examine chromatin condensation. Flow cytometry assay was used to measure total viable cells, cell cycle and sub-G₁ phase distribution, reactive oxygen species (ROS), Ca²⁺, and mitochondria membrane potential (ΔΨm) in NPC-TW 076 cells. Results indicate that TET induced cell death through the cell morphological changes, caused G₀/G₁ phase arrest, increased ROS and Ca²⁺ production, and finally caused apoptotic cell death in NPC-TW 076 cells. There was no influence on the level of ΔΨm after TET treatment. Western blotting indicated that TET increased endoplasmic reticulum (ER) stress associated protein expression such as GADD153, GRP78, ATF-6α and ATF-6 βwhich indicated that TET induced cell death through ER stress. ER stress is a potential target in cancer treatment, so the ability of TET to induce ER stress response and to activate programming cell death in NPC-TW 076 cells make this molecule become a promising anticancer agent.