The apoptotic effect of D Rhamnose β-hederin, a novel oleanane-type triterpenoid saponin on breast cancer cells

Natural products target pyroptosis for ameliorating neuroinflammation: A novel antidepressant strategy

BACKGROUND

Depression is a common mental disorder characterized by prolonged loss of interest and low mood, accompanied by symptoms such as sleep disturbances and cognitive impairments. In severe cases, there may be a tendency toward suicide. Depression can be caused by a series of highly complex pathological mechanisms; However, its key pathogenic mechanism remains unclear. As a novel programmed cell death (PCD) pathway and inflammatory cell death mode, pyroptosis involves a series of tightly regulated gene expression events. It may play a significant role in the pathogenesis and management of depression by modulating neuroinflammatory processes. In addition, a large number of studies have shown that various pharmacologically active natural products can regulate pyroptosis through multiple targets and pathways, demonstrating significant potential in the treatment of depression. These natural products offer advantages such as low costs and minimal side effects, making them a viable supplement or alternative to traditional antidepressants. In this review, we summarized recent research on natural products that regulate pyroptosis and neuroinflammation to improve depression. The aim of this review was to contribute to a scientific basis for the discovery and development of more natural antidepressants in the future.

METHODS

To review the antidepressant effects of natural products targeting pyroptosis-mediated neuroinflammation, data were collected from the Web of Science, ScienceDirect databases, and PubMed to classify and summarize the relationship between pyroptosis and neuroinflammation in depression, as well as the pharmacological mechanisms of natural products.

RESULTS

Multiple researches have revealed that pyroptosis-mediated neuroinflammation serves as a pivotal contributory factor in the pathological process of depression. Natural products, such as terpenoids, terpenes, phenylethanol glycosides, and alkaloids, have antidepressant effects by regulating pyroptosis to alleviate neuroinflammation.

CONCLUSION

We comprehensively reviewed the regulatory effects of natural products in depression-related pyroptosis pathways, providing a uniquely insightful perspective for the research, development, and application of natural antidepressants. However, future research should further explore the modulatory mechanisms of natural products in regulating pyroptosis, which is of great importance for the genration of effective antidepressants.

Plant-Based Anticancer Compounds With a Focus on Breast Cancer

Breast cancer is a common form of cancer among women characterized by the growth of malignant cells in the breast tissue. The most common treatments for this condition include chemotherapy, surgical intervention, radiation therapy, hormone therapy, and biological therapy. The primary issues associated with chemotherapy and radiation therapy are their adverse events and significant financial burden among patients in underdeveloped countries. This highlights the need to explore and develop superior therapeutic options that are less detrimental and more economically efficient. Plants provide an abundant supply of innovative compounds and present a promising new avenue for investigating cancer. Plants and their derivations are undergoing a revolution due to their reduced toxicity, expediency, cost-effectiveness, safety, and simplicity in comparison to conventional treatment methods. Natural products are considered promising candidates for the development of anticancer drugs, due perhaps to the diverse pleiotropic effects on target events. The effects of plant-derived products are limited to cancer cells while leaving healthy cells unaffected. Identification of compounds with strong anticancer properties and development of plant-based medications for cancer treatment might be crucial steps in breast cancer therapy. Although bioactive compounds have potent anticancer properties, they also have drawbacks that need to be resolved before their application in clinical trials and improved for the approved drugs. This study aims to give comprehensive information on known anticancer compounds, including their sources and molecular mechanisms of actions, along with opportunities and challenges in plant-based anticancer therapies.

The Cytotoxicity of Carbon Nanotubes and Hydroxyapatite, and Graphene and Hydroxyapatite Nanocomposites against Breast Cancer Cells

Cancer is a current dreadful disease and the leading cause of death. Next to cardiovascular diseases, cancer is the most severe threat to human life and health. Breast cancer is the most common invasive cancer diagnosed in women. Each year about 2.3 million women are diagnosed with breast cancer. In consideration of the severity of breast cancer, herein we designed the biocompatible nanomaterials, CNTs-HAP and GR-HAP, through grafting of hydroxyapatite (HAP) to carbon nanotubes (CNTs) and graphene (GR) nanosheets. CNTs-HAP and GR-HAP have been tested for their cytotoxicity, growth and motility inhibitory effects, and their effects on the mesenchymal markers. All these demonstrated significant dose-dependent and time-dependent in vitro cytotoxicity against SUM-159 and MCF-7 breast cancer cell lines. The cell viability assay showed that the CNTs-HAP was more effective over SUM-159 cells than MCF-7 cells. It found that the increase in the concentration of GR-HAP has inhibited the clonogenic ability of breast cancer cells. The GR-HAP exhibited a substantial inhibitory effect on the cell motility of SUM-159 cell lines. It was investigated that the expression of vimentin (mesenchymal marker) was majorly reduced in SUM-159 cells by GR-HAP.

Role of Medicinal plant-derived Nutraceuticals as a potential target for the treatment of breast cancer

Breast cancer (BC) is one of the most challenging cancers to treat, accounting for many cancer-related deaths. Over some years, chemotherapy, hormone treatment, radiation, and surgeries have been used to treat cancer. Unfortunately, these treatment options are unsuccessful due to crucial adverse reactions and multidrug tolerance/resistance. Although it is clear that substances in the nutraceuticals category have a lot of anti-cancer activity, using a supplementary therapy strategy, in this case, could be very beneficial. Nutraceuticals are therapeutic agents, which are nutrients that have drug-like characteristics and can be used to treat diseases. Plant nutraceuticals categorized into polyphenols, terpenoids, vitamins, alkaloids, and flavonoids are part of health food products, that have great potential for combating BC. Nutraceuticals can reduce BC's severity, limit malignant cell growth, and modify cancer-related mechanisms. Nutraceuticals acting by attenuating Hedgehog, Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), Notch, and Wnt/β-catenin signaling are the main pathways in controlling the self-renewal of breast cancer stem cells (BCSCs). This article reviews some important nutraceuticals and their modes of action, which can be very powerful versus BC. PRACTICAL APPLICATIONS: Nutraceuticals' importance to the control and diagnosis of breast cancer is undeniable and cannot be overlooked. Natural dietary compounds have a wide range of uses and have been used in traditional medicine. In addition, these natural chemicals can enhance the effectiveness of other traditional medicines. They may also be used as a treatment process independently because of their capacity to affect several cancer pathways. This study highlights a variety of natural chemicals, and their mechanisms of action, routes, synergistic effects, and future potentials are all examined.

Promoting Apoptosis, a Promising Way to Treat Breast Cancer With Natural Products: A Comprehensive Review

Breast cancer is one of the top-ranked malignant carcinomas associated with morbidity and mortality in women worldwide. Chemotherapy is one of the main approaches to breast cancer treatment. Breast cancer initially responds to traditional first- and second-line drugs (aromatase inhibitor, tamoxifen, and carboplatin), but eventually acquires resistance, and certain patients relapse within 5 years. Chemotherapeutic drugs also have obvious toxic effects. In recent years, natural products have been widely used in breast cancer research because of their low side effects, low toxicity, and good efficacy based on their multitarget therapy. Apoptosis, a programmed cell death, occurs as a normal and controlled process that promotes cell growth and death. Inducing apoptosis is an important strategy to control excessive breast cancer cell proliferation. Accumulating evidence has revealed that natural products become increasingly important in breast cancer treatment by suppressing cell apoptosis. In this study, we reviewed current studies on natural product–induced breast cancer cell apoptosis and summarized the proapoptosis mechanisms including mitochondrial, FasL/Fas, PI3K/AKT, reactive oxygen species, and mitogen-activated protein kinase–mediated pathway. We hope that our review can provide direction in the search for candidate drugs derived from natural products to treat breast cancer by promoting cell apoptosis.

Zingiberensis Newsaponin Inhibits the Malignant Progression of Hepatocellular Carcinoma via Suppressing Autophagy Moderated by the AKR1C1-Mediated JAK2/STAT3 Pathway

Objective

Saponins are a group of compounds from various plants, which exhibit an anticancer activity. This study aimed to explore the anticancer effect of zingiberensis newsaponin (ZnS) against hepatocellular carcinoma (HCC) and the underlying mechanism involving autophagy.

Methods

HCC cells (Huh7 and SMMC7721) were treated with ZnS and/or 3-MA. The cell viability, migration, and apoptosis were determined using CCK-8 assay, transwell assay, and flow cytometry, respectively. The levels of oxidative stress markers (ROS, SOD, and MDA) were measured by ELISA assay. Autophagy was monitored using MDC assay, immunofluorescence staining, and transmission electron microscopy. The relative protein expression of LC3II/LC3I, P62, AKR1C1, p-JAK2, p-STAT3, JAK2, and STAT3 was determined using Western blot.

Results

ZnS or 3-MA inhibited the cell viability and migration, and it promoted cell apoptosis and oxidative stress in HCC. MDC-positive cells and autophagosomes were reduced by ZnS or 3-MA treatment. The expression of autophagy-related proteins LC3 (LC3II/LC3I) and P62 was, respectively, downregulated and upregulated after ZnS or 3-MA treatment. In addition, ZnS or 3-MA suppressed the protein expression of AKR1C1, p-JAK2, and p-STAT3 in HCC cells. Furthermore, the above phenomena were evidently enhanced by ZnS combined 3-MA treatment. AKR1C1 overexpression weakened the effect of ZnS on inhibiting the expression of AKR1C1, p-JAK2, and p-STAT3.

Conclusion

ZnS exerts an anticancer effect on HCC via inhibiting autophagy moderated by the AKR1C1-mediated JAK2/STAT3 pathway. ZnS and 3-MA exert a synergistic effect on inhibiting HCC.

Synthetic and Naturally Occurring Heterocyclic Anticancer Compounds with Multiple Biological Targets

Cancer is a complex group of diseases initiated by abnormal cell division with the potential of spreading to other parts of the body. The advancement in the discoveries of omics and bio- and cheminformatics has led to the identification of drugs inhibiting putative targets including vascular endothelial growth factor (VEGF) family receptors, fibroblast growth factors (FGF), platelet derived growth factors (PDGF), epidermal growth factor (EGF), thymidine phosphorylase (TP), and neuropeptide Y4 (NY4), amongst others. Drug resistance, systemic toxicity, and drug ineffectiveness for various cancer chemo-treatments are widespread. Due to this, efficient therapeutic agents targeting two or more of the putative targets in different cancer cells are proposed as cutting edge treatments. Heterocyclic compounds, both synthetic and natural products, have, however, contributed immensely to chemotherapeutics for treatments of various diseases, but little is known about such compounds and their multimodal anticancer properties. A compendium of heterocyclic synthetic and natural product multitarget anticancer compounds, their IC50, and biological targets of inhibition are therefore presented in this review.

ERK: A Double-Edged Sword in Cancer. ERK-Dependent Apoptosis as a Potential Therapeutic Strategy for Cancer

The RAF/MEK/ERK signaling pathway regulates diverse cellular processes as exemplified by cell proliferation, differentiation, motility, and survival. Activation of ERK1/2 generally promotes cell proliferation, and its deregulated activity is a hallmark of many cancers. Therefore, components and regulators of the ERK pathway are considered potential therapeutic targets for cancer, and inhibitors of this pathway, including some MEK and BRAF inhibitors, are already being used in the clinic. Notably, ERK1/2 kinases also have pro-apoptotic functions under certain conditions and enhanced ERK1/2 signaling can cause tumor cell death. Although the repertoire of the compounds which mediate ERK activation and apoptosis is expanding, and various anti-cancer compounds induce ERK activation while exerting their anti-proliferative effects, the mechanisms underlying ERK1/2-mediated cell death are still vague. Recent studies highlight the importance of dual-specificity phosphatases (DUSPs) in determining the pro- versus anti-apoptotic function of ERK in cancer. In this review, we will summarize the recent major findings in understanding the role of ERK in apoptosis, focusing on the major compounds mediating ERK-dependent apoptosis. Studies that further define the molecular targets of these compounds relevant to cell death will be essential to harnessing these compounds for developing effective cancer treatments.

Natural Compounds in Sex Hormone-Dependent Cancers: The Role of Triterpenes as Therapeutic Agents

Sex hormone-dependent cancers currently contribute to the high number of cancer-related deaths worldwide. The study and elucidation of the molecular mechanisms underlying the progression of these tumors was a double-edged sword, leading to the expansion and development of new treatment options, with the cost of triggering more aggressive, therapy resistant relapses. The interaction of androgen, estrogen and progesterone hormones with specific receptors (AR, ER, PR) has emerged as a key player in the development and progression of breast, ovarian, prostate and endometrium cancers. Sex hormone-dependent cancers share a common and rather unique carcinogenesis mechanism involving the active role of endogenous and exogenous sex hormones to maintain high mitotic rates and increased cell proliferation thus increasing the probability of aberrant gene occurrence and accumulation highly correlated with abnormal cell division and the occurrence of malignant phenotypes. Cancer related hormone therapy has evolved, currently being associated with the blockade of other signaling pathways often associated with carcinogenesis and tumor progression in cancers, with promising results. However, despite the established developments, there are still several shortcomings to be addressed. Triterpenes are natural occurring secondary metabolites biosynthesized by various pathways starting from squalene cyclization. Due to their versatile therapeutic potential, including the extensively researched antiproliferative effect, these compounds are most definitely a cornerstone in the research and development of new natural/semisynthetic anticancer therapies. The present work thoroughly describes the ongoing research related to the antitumor activity of triterpenes in sex hormone-dependent cancers. Also, the current review highlights both the biological activity of various triterpenoid compounds and their featured mechanisms of action correlated with important chemical structural features.

Metformin exhibits antiproliferation activity in breast cancer via miR-483-3p/METTL3/m6A/p21 pathway

Evidence suggests that metformin might be a potential candidate for breast cancer treatment. Yet, its relevant molecular mechanisms remain to be fully investigated. We found that metformin could suppress the N6-methyladenosine (m6A) level in breast cancer cells significantly. The latter has an essential role in breast cancer progression and is newly considered as a therapeutic target. In this study, we measured the m6A level by m6A colorimetric analysis and dot blot assay. We then performed qRT-PCR, western blot, MeRIP, dual-luciferase reporter assay, and others to explore the m6A-dependent pathway associated with metformin. In vivo effect of metformin was investigated using a mouse tumorigenicity model. In addition, breast cancer and normal tissues were used to determine the role of METTL3 in breast cancer. Metformin could reduce the m6A level via decreasing METTL3 expression mediated by miR-483-3p in breast cancer. METTL3 is known to be able to promote breast cancer cell proliferation by regulating the p21 expression by an m6A-dependent manner. Metformin can take p21 as the main target to inhibit such effect. To specify, this study exhibited that metformin can inhibit breast cancer cell proliferation through the pathway miR-483-3p/METTL3/m6A/p21. Our findings suggest that METTL3 may be considered as a potential therapeutic target of metformin for breast cancer.

α-hederin induces autophagic cell death in colorectal cancer cells through reactive oxygen species dependent AMPK/mTOR signaling pathway activation

α-hederin, a monodesmosidic triterpenoid saponin, had previously demonstrated strong anticancer effects. In the current study, the pharmacological mechanism of autophagic cell death induced by α-hederin was investigated in human colorectal cancer cells. First, through cell counting kit-8 and colony formation assays, it was demonstrated that α-hederin could inhibit the proliferation of HCT116 and HCT8 cell. Results of flow cytometry using fluorescein isothiocyanate Annexin V/propidium iodide and Hoechst 33258 staining indicated that α-hederin could induce apoptosis. Western blotting demonstrated that α-hederin could activate mitochondrial apoptosis signal pathway. Then, using light chain 3 lentiviral and electron microscope assay, it was demonstrated that α-hederin could induce autophagy in colorectal cancer cells. In addition, immunohistochemistry results from in vivo experiments also demonstrated that α-hederin could induce autophagy. AMP-activated protein kinase (AMPK)/mechanistic target of rapamycin (mTOR) signaling was demonstrated to be activated by α-hederin, which could be blocked by reactive oxygen species (ROS) inhibitor NAC. Furthermore, NAC could inhibit apoptosis and autophagy induced by α-hederin. Finally, 3-MA (autophagy inhibitor) reduced the inhibition of α-hederin on cell activity, but it had no significant effect on apoptosis. In conclusion, α-hederin triggered apoptosis through ROS-activated mitochondrial signaling pathway and autophagic cell death through ROS dependent AMPK/mTOR signaling pathway activation in colorectal cancer cells.

d Rhamnose β-hederin reverses chemoresistance of breast cancer cells by regulating exosome-mediated resistance transmission

d Rhamnose β-hederin (DRβ-H), an active component extracted from the traditional Chinese medicinal plant Clematis ganpiniana, has been reported to be effective against breast cancer. Recent studies have also indicated that the isolated exosomes (D/exo) from docetaxel-resistant breast cancer cells MCF-7 (MCF-7/Doc) were associated with resistance transmission by delivering genetic cargo. However, the relevance of D/exo during DRβ-H exposure remains largely unclear. In the present work, exosomes were characterized by morphology and size distribution. We reinforced the significant role of D/exo in spreading chemoresistance from MCF-7/Doc to recipient sensitive cells after absorption and internalization. DRβ-H could reduce the formation and release of D/exo. Next, we demonstrated that DRβ-H was able to reverse docetaxel resistance and that D/exo was responsible for DRβ-H-mediated resistance reversal. We also found that DRβ-H could decrease the expressions of several most abundant miRNAs (miR-16, miR-23a, miR-24, miR-26a, and miR-27a) transported by D/exo. Target gene prediction and pathway analysis showed the involvement of these selected miRNAs in pathways related to treatment failure. Our results suggested that DRβ-H could reduce D/exo secretion from MCF-7/Doc cells and induce the reduction in resistance transmission via D/exo.

D Rhamnose β-Hederin against human breast cancer by reducing tumor-derived exosomes

D Rhamnose β-hederin (DRβ-H), a novel oleanane-type triterpenoid saponin isolated from the traditional Chinese medicinal plant Clematis ganpiniana, has been demonstrated to be effective against various types of tumor. However, the exact role of DRβ-H on breast cancer remains largely unresolved. In the present study, it was observed that DRβ-H exhibited anti-proliferative and pro-apoptotic activity in human breast cancer cells (MCF-7/S). DRβ-H was able to inhibit exosome secretion, and the level of exosomes was positively associated with cell growth after absorption and internalization by target breast cancer cells. By analyzing the miRNA profiles of exosomes and MCF-7/S, it was identified that several miRNAs were detected exclusively in exosomes. Knockdown of the top five exosomal miRNAs and an MCF-7/S proliferation assay indicated that exosomal miR-130a and miR-425 may enhance MCF-7/S cell viability. Target gene prediction and pathway analysis revealed the involvement of miR-130a and miR-425 in pathways associated with malignant cell proliferation. These results demonstrated that DRβ-H inhibited MCF-7/S cell growth through reducing exosome release.

Ophiopogonin D', a Natural Product From Radix Ophiopogonis, Induces in Vitro and in Vivo RIPK1-Dependent and Caspase-Independent Apoptotic Death in Androgen-Independent Human Prostate Cancer Cells

Objective: The purpose of this study was to evaluate the anticancer effects of Ophiopogonin D′ (OPD′, a natural product extracted from a traditional Chinese medicine (Radix Ophiopogonis) against androgen-independent prostate cancer cells and to explore the underlying molecular mechanism(s) of action.

Methods: The CCK-8 assay was used to assess the viability of prostate cancer cells. The cell morphology was examined by an ultrastructural analysis via transmission electron microscopy. Cells in apoptosis (early and late stages) were detected using an Annexin V-FITC/propidium iodide kit with a FACSCaliber flow cytometer. JC-1, a cationic lipophilic probe, was employed to measure the mitochondrial membrane potential (MMP) of PC3 cells. Changes in the protein expression of RIPK1, C-RIPK1, caspase 8, cleaved-caspase 8, Bim, Bid, caspase 10, and cleaved-caspase 10 were evaluated by Western blotting. The mRNA expression of Bim was examined by quantitative real-time reverse transcription polymerase chain reaction. Z-VAD-FMK (a caspase inhibitor) and necrostatin-1 (a specific inhibitor of RIPK1) were utilized to determine whether the cell death was mediated by RIPK1 or caspases. PC3 and DU145 xenograft models in BALB/c nude mice were used to evaluate the anticancer activity of OPD′ in vivo.

Results: OPD′ was shown to exert potent anti-tumor activity against PC3 cells. It induced apoptosis via a RIPK1-related pathway, increased the protein expression levels of RIPK1 and Bim, and decreased the levels of cleaved-RIPK1, caspase 8, cleaved-caspase 8, Bid, caspase 10, and cleaved-caspase 10. OPD′ also increased the mRNA expression of Bim. The protein expression of Bim was decreased when cells were pre-treated with necrostatin-1. Treatment with OPD′ inhibited the growth of PC3 and DU145 xenograft tumors in BALB/c nude mice.

Conclusion: OPD′ significantly inhibited the in vitro and in vivo growth of prostate cells via RIPK1, suggesting that OPD′ may be developed as a potential anti-prostate cancer agent.

Glycyrrhetinic Acid Functionalized Graphene Oxide for Mitochondria Targeting and Cancer Treatment In Vivo

Mitochondria-mediated apoptosis (MMA) is a preferential option for cancer therapy due to the presence of cell-suicide factors in mitochondria, however, low permeability of mitochondria is a bottleneck for targeting drug delivery. In this paper, glycyrrhetinic acid (GA), a natural product from Glycyrrhiza glabra, is found to be a novel mitochondria targeting ligand, which can improve mitochondrial permeability and enhance the drug uptake of mitochondria. GA-functionalized graphene oxide (GO) is prepared and used as an effective carrier for targeted delivery of doxorubicin into mitochondria. The detailed in vitro and in vivo mechanism study shows that GA-functionalized GO causes a decrease in mitochondrial membrane potential and activates the MMA pathway. The GA-functionalized drug delivery system demonstrates highly improved apoptosis induction ability and anticancer efficacy compared to the non-GA-functionalized nanocarrier delivery system. The GA-functionalized nanocarrier also shows low toxicity, suggesting that it can be a useful tool for drug delivery.

Phytochemicals and PI3K Inhibitors in Cancer-An Insight

In today's world of modern medicine and novel therapies, cancer still remains to be one of the prime contributor to the death of people worldwide. The modern therapies improve condition of cancer patients and are effective in early stages of cancer but the advanced metastasized stage of cancer remains untreatable. Also most of the cancer therapies are expensive and are associated with adverse side effects. Thus, considering the current status of cancer treatment there is scope to search for efficient therapies which are cost-effective and are associated with lesser and milder side effects. Phytochemicals have been utilized for many decades to prevent and cure various ailments and current evidences indicate use of phytochemicals as an effective treatment for cancer. Hyperactivation of phosphoinositide 3-kinase (PI3K) signaling cascades is a common phenomenon in most types of cancers. Thus, natural substances targeting PI3K pathway can be of great therapeutic potential in the treatment of cancer patients. This chapter summarizes the updated research on plant-derived substances targeting PI3K pathway and the current status of their preclinical studies and clinical trials.

A hederagenin saponin isolated from Clematis ganpiniana induces apoptosis in breast cancer cells via the mitochondrial pathway

Natural plants offer a treasure trove of resources for anticancer drug development. Clematis are widely used in Traditional Chinese Medicine. However, studies on the active substances in Clematis are scarce. In the present study, four monomer compounds were successfully extracted from this species and their inhibitory effects on the growth of breast cancer cells were investigated using bioactivity tests. Among them, Clematis hederagenin saponin (CHS) belongs to the class of triterpenoid saponins. CHS showed cytotoxic effects on breast cancer cells in a dose- and time-dependent manner. The compound also induced apoptosis in breast cancer cells in a time-dependent manner. Further investigation into the underlying mechanisms of apoptosis induction in breast cancer cells showed that the compound significantly reduced mitochondrial Apaf-1 and cytochrome c proteins in breast cancer cells. In addition, it upregulated the activities of caspase-3 and −9. In conclusion, CHS induced apoptosis in breast cancer cells through regulation of the mitochondrial apoptosis pathway. The results suggest that the hederagenin saponin extracted from Clematis ganpiniana offers great potential as a novel anti-breast cancer drug.

Betulinic acid induces apoptosis by regulating PI3K/Akt signaling and mitochondrial pathways in human cervical cancer cells

Betulinic acid (BA), a potential anticancer compound, could induce apoptosis in human cervical cancer (HeLa) cells, but its mechanism has yet to be fully elucidated. The present study was focused on deciphering the detailed molecular mechanism of BA-induced apoptosis. In the present study, results indicated that BA was highly effective against HeLa cells via induction of time-dependent apoptosis, and the authors demonstrated that the BA treatment acted through downregulating a phosphatidylinositol 3-kinase (PI3K) subunit and suppressing the Akt phosphorylation at Thr308 and Ser473 after increasing the generation of intracellular reactive oxygen species. Then, BA induced cell cycle arrest at the G0/G1 phase, which was consistent with the cell cycle-related protein results in which BA significantly enhanced the expression of p27Kip and p21Waf1/Cip1 in HeLa cells. This target-specific inhibition was associated with mitochondrial apoptosis, as reflected by the increased expression of Bad and caspase-9, the generation of reactive oxygen species (ROS) and the decline in mitochondrial membrane potential. Moreover, preincubation of the cells with glutathione (antioxidant) blocked the process of apoptosis, prevented the phosphorylation of downstream substrates. These results established that ROS acted as a key factor to effect apoptosis by BA treatment in HeLa cells. Therefore, these findings demonstrated that BA induced apoptosis in HeLa cells by downregulating the expression of PI3K/Akt signaling molecules via ROS, and triggering a mitochondrial pathway.

Cytotoxic and Hypoglycemic Activity of Triterpenoid Saponins from Camellia oleifera Abel. Seed Pomace

One new and three known triterpenoid saponins were isolated and identified from Camellia oleifera seeds through IR, NMR, HR-ESI-MS and GC-MS spectroscopic methods, namely oleiferasaponin A₃, oleiferasaponin A₁, camelliasaponin B₁, and camelliasaponin B₂. The structure of oleiferasaponin A₃ was elucidated as 16α-hydroxy-21β-O-angeloyl-22α-O-cinnamoyl-23α-aldehyde-28-dihydroxymethylene-olean-12-ene-3β-O-[β-d-galactopyranosyl-(1→2)]-[β-d-xylopyranosyl-(1→2)-β-d-galactopyranosyl-(1→3)]-β-d-gluco-pyranosiduronic acid. Camelliasaponin B₁ and camelliasaponin B₂ exhibited potent cytotoxic activity on three human tumour cell lines (human lung tumour cells (A549), human liver tumour cells (HepG2), cervical tumour cells (Hela)). The hypoglycemic activity of oleiferasaponin A₁ was testified by protecting pancreatic β-cell lines from high-glucose damage.

Anticancer Effects of Sinocrassulosides VI/VII from Silene viscidula on HeLa Cells

Natural products are becoming increasingly important in chemoprevention and for cancer therapy. Silene viscidula (S. viscidula), a traditional Chinese herb, has long been used as an anti-inflammatory and neuroleptic agent. However, the anticancer activity of S. viscidula has remained unclear. In this study, 16 compounds were extracted from S. viscidula. Among those compounds, sinocrassulosides VI/VII, an inseparable isomer mixture, possess the strongest inhibitory activity on HeLa cells with the IC₅₀ value of 2.37 μM. Mechanism studies found that sinocrassulosides VI/VII downregulated the expression of cyclin D1 and decreased retinoblastoma (Rb) phosphorylation, which arrested HeLa cells in the G1 phase. Also, sinocrassulosides VI/VII could induce senescence via the upregulation of p16 and a significant increase of β-galactosidase (β-gal) staining. Our results suggest that sinocrassulosides VI/VII may be a new therapeutic potential agent for cervical cancer. In addition, we explored the structure-activity relationships of three groups of the configurational isomer with similar chemical structure from S. viscidula. We first demonstrated that the length of the ester chains linked to the carboxyl group of the glucuronic acid residue could affect the potent cytotoxicity. This finding will open new avenues for developing effective anticancer compounds by modifying the components derived from plants in nature.

Anticancer Chemodiversity of Ranunculaceae Medicinal Plants: Molecular Mechanisms and Functions

The buttercup family, Ranunculaceae, comprising more than 2,200 species in at least 62 genera, mostly herbs, has long been used in folk medicine and worldwide ethnomedicine since the beginning of human civilization. Various medicinal phytometabolites have been found in Ranunculaceae plants, many of which, such as alkaloids, terpenoids, saponins, and polysaccharides, have shown anti-cancer activities in vitro and in vivo. Most concerns have been raised for two epiphany molecules, the monoterpene thymoquinone and the isoquinoline alkaloid berberine. At least 17 genera have been enriched with anti-cancer phytometabolites. Some Ranunculaceae phytometabolites induce the cell cycle arrest and apoptosis of cancer cells or enhance immune activities, while others inhibit the proliferation, invasion, angiogenesis, and metastasis, or reverse the multi-drug resistance of cancer cells thereby regulating all known hallmarks of cancer. These phytometabolites could exert their anti-cancer activities via multiple signaling pathways. In addition, absorption, distribution, metabolism, and excretion/toxicity properties and structure/activity relationships of some phytometabolites have been revealed assisting in the early drug discovery and development pipelines. However, a comprehensive review of the molecular mechanisms and functions of Ranunculaceae anti-cancer phytometabolites is lacking. Here, we summarize the recent progress of the anti-cancer chemo- and pharmacological diversity of Ranunculaceae medicinal plants, focusing on the emerging molecular machineries and functions of anti-cancer phytometabolites. Gene expression profiling and relevant omics platforms (e.g. genomics, transcriptomics, proteomics, and metabolomics) could reveal differential effects of phytometabolites on the phenotypically heterogeneous cancer cells.

Oleiferasaponin C6 from the seeds of Camellia oleifera Abel.: a novel compound inhibits proliferation through inducing cell-cycle arrest and apoptosis on human cancer cell lines in vitro

Oleiferasaponin C₆ was isolated from Camellia oleifera Abel. and inhibits proliferation through inducing cell-cycle arrest and apoptosis on cancer cell lines in vitro.

Caspase-9 as a therapeutic target for treating cancer

INTRODUCTION

Caspase-9 is the apoptotic initiator protease of the intrinsic or mitochondrial apoptotic pathway, which is activated at multi-protein activation platforms. Its activation is believed to involve homo-dimerization of the monomeric zymogens. It binds to the apoptosome to retain substantial catalytic activity. Variety of apoptotic stimuli can regulate caspase-9. However, the mechanism of action of various regulators of caspase-9 has not been summarized and compared yet. In this article, we elucidate the regulators of caspase-9 including microRNAs, natural compounds that are related to caspase-9 and ongoing clinical trials with caspase-9 to better understand the caspase-9 in suppressing cancer.

AREAS COVERED

In this study, the basic mechanism of apoptosis pathways, regulators of caspase-9 and the development of drugs to regulate caspase-9 are reviewed. Also, ongoing clinical trials for caspase-9 are discussed.

EXPERT OPINION

Apoptosis has crucial role in cancer, brain disease, aging and heart disease to name a few. Since caspase-9 is an initiator caspase of apoptosis, it is an important therapeutic target of various diseases related to apoptosis. Therefore, a deep understanding on the roles as well as regulators of caspase-9 is required to find more effective ways to conquer apoptosis-related diseases especially cancer.