Chemosensitizing effect of Paris Saponin I on Camptothecin and 10-hydroxycamptothecin in lung cancer cells via p38 MAPK, ERK, and Akt signaling pathways

Research trends and hotspots of polyphyllin in high-incidence cancers: A bibliometric analysis

Background

Polyphyllin, a natural compound derived primarily from the Paris genus, manifests its anticancer properties. Extensive research on its therapeutic potential in cancers has been reported. However, there is no systematical analysis of the general aspects of research on polyphyllin by bibliometric analysis. The aim of this study is to visualize emerging trends and hotspots and predict potential research directions in this field.

Methods

In this study, we collected relevant research articles from the Web of Science Core Collection Bibliometrics. Using R-bibliometrix, we analyzed the research status, hotspots, frontiers, and development trends of polyphyllin in high-incidence cancers. To conduct a comprehensive visual analysis, CiteSpace and VOSviewer were used for visual analysis of authors, countries, institutions, keywords, and co-cited references within the published articles.

Results

A total of 257 articles focusing on the research of polyphyllin in high-incidence cancers were retrieved from the WOSCC database, covering the period from 2005 to 2023. The analysis revealed a consistent increasing trend in annual publications during this timeframe. Notably, China emerged as the most productive country, with Tianjin University leading the institutions. The Journal of Ethnopharmacology stood out as the most prominent journal in this field, while Gao WY emerged as the most prolific author. Polyphyllin VI, polyphyllin II, and polyphyllin VII have emerged as the latest research hotspots. Additionally, the investigation of autophagy and its associated mechanisms has gained significant attention as a novel research direction.

Conclusion

This study presents a novel visualization of the research on polyphyllin saponins in the field of highly prevalent cancers using bibliometric analysis. The investigation of polyphyllin D has emerged as a primary focus in this field, with lung cancer, breast cancer, and liver cancer being the key areas of current research. Lastly, polyphyllin saponins show potential application in the field of cancer.

The Application of Nano-drug Delivery System With Sequential Drug Release Strategies in Cancer Therapy

Currently, multidrug combinations are often used clinically to improve the efficacy of oncology chemotherapy, but multidrug combinations often lead to multidrug resistance and decreased performance, resulting in more severe side effects than monotherapy. Therefore, sequential drug release strategies in time and space as well as nano-carriers that respond to the tumor microenvironment have been developed. First, the advantage of the sequential release strategy is that they can load multiple drugs simultaneously to meet their spatiotemporal requirements and stability, thus exerting synergistic effects of two or more drugs. Second, in some cases, sequential drug delivery of different molecular targets can improve the sensitivity of cancer cells to drugs. Control the metabolism of cancer cells, and remodel tumor vasculature. Finally, some drug combinations with built-in release control are used for sequential administration. This paper focuses on the use of nanotechnology and built-in control device to construct drug delivery carriers with different stimulation responses, thus achieving the sequential release of drugs. Therefore, the nano-sequential delivery carrier provides a new idea and platform for the therapeutic effect of various drugs and the synergistic effect among drugs.

Polyphyllin D induces necroptosis in neuroblastoma cells (IMR-32 and LA-N-2) in mice

BACKGROUND

We previously reported that polyphyllin D, the main component of the traditional herbal medicinal Paris polyphylla, exhibited anticancer effects in vitro against human neuroblastoma cells. The aim of this investigation was to examine in vivo antitumor effects of polyphyllin D.

METHODS

Subcutaneous tumors were established in immune-deficient BALB/c nude mice using human neuroblastoma cell lines IMR-32 and LA-N-2. To evaluate the polyphyllin D activity, we used a mouse model of IMR-32 or LA-N-2 cell lines and analyzed subcutaneous tumors.

RESULTS

Subcutaneous tumor models were successfully established in mice using two human neuroblastoma cell lines. In the subcutaneous tumor model, porphyrin D was found to suppress tumor volume. We found that polyphyllin D suppressed the number of foci by Ki-67 staining (IMR-32 and LA-N-2; p < 0.01, 0.02, respectively). We found that polyphyllin D induces the RIPK3 expression, while polyphyllin D phosphorylates Ser358 in IMR-32 and Ser358 and Tyr376 in LA-N-2.

CONCLUSION

We developed a mouse model of subcutaneous tumors of neuroblastoma and demonstrated for the first time that polyphyllin D has an antitumor effect on neuroblastoma. Polyphyllin D can cause necroptosis depending on the cell type. The new drug can be expected by investigating a method to selectively induce cell death through the analysis of necroptosis.

Effects of saponins from Chinese herbal medicines on signal transduction pathways in cancer: A review

Cancer poses a serious threat to human health, and the search for safe and effective drugs for its treatment has aroused interest and become a long-term goal. Traditional Chinese herbal medicine (TCM), an ancient science with unique anti-cancer advantages, has achieved outstanding results in long-term clinical practice. Accumulating evidence shows that saponins are key bioactive components in TCM and have great research and development applications for their significant role in the treatment of cancer. Saponins are a class of glycosides comprising nonpolar triterpenes or sterols attached to hydrophilic oligosaccharide groups that exert antitumor effects by targeting the NF-κB, PI3Ks-Akt-mTOR, MAPK, Wnt-β-catenin, JAK-STAT3, APMK, p53, and EGFR signaling pathways. Presently, few advances have been made in physiological and pathological studies on the effect of saponins on signal transduction pathways involved in cancer treatment. This paper reviews the phytochemistry and extraction methods of saponins of TCM and their effects on signal transduction pathways in cancer. It aims to provide theoretical support for in-depth studies on the anticancer effects of saponins.

Beneficial effects of genistein in suppression of proliferation, inhibition of metastasis, and induction of apoptosis in PC3 prostate cancer cells

OBJECTIVES

Beneficial effects of genistein have been studied in various cancer types but the underlying molecular mechanisms of its actions have not been well established. This study investigated the effects of genistein on caspase-3 and p38 mitogen-activated protein kinase (p38MAPK) as main cellular signalling targets in PC3 prostate cancer cells.

METHODS

Caspase-3 and p38MAPK gene expression and intracellular protein levels were determined. Matrix metalloproteinase-2 (MMP2) gelatinase activity and caspase-3 enzyme activity were measured and PC3 cell migration and proliferation potencies were assessed.

RESULTS

Genistein induced apoptosis by enhancing the gene expression, intracellular protein level, and enzyme activity of caspase-3. Genistein also inhibited cell proliferation by reducing p38MAPK gene expression and protein level and strongly suppressed metastatic potency of PC3 cells by reducing MMP2 activity.

CONCLUSION

Genistein exhibits its beneficial anticancer properties on PC3 cells by reducing metastatic potency and regulating caspase-3 and p38MAPK pathways at different transcriptional and protein levels.

PCAT19 Regulates the Proliferation and Apoptosis of Lung Cancer Cells by Inhibiting miR-25-3p via Targeting the MAP2K4 Signal Axis

Both PCAT19 and miR-25-3p have been reported in lung cancer studies, but whether there is a correlation between the two and whether they jointly regulate the progress of lung cancer have not been reported yet. Therefore, this study carried out a further in-depth research. The expression of PCAT19 was detected in lung cancer (LC) tissues and cells by quantitative real-time polymerase chain reaction (qRT-PCR). The effect of PCAT19 on tumor growth was detected in a tumor-bearing model of nude mice. PCAT19-transfected cells were treated with Honokiol and anisomycin. The effects of PCAT19 on proliferation, apoptosis, and cycle of LC cells were investigated by biomolecule experiments. The effects of PCAT19 on the expressions of mitogen-activated protein kinase- (MAPK-) related proteins were evaluated by western blotting. The expression of PCAT19 was decreased in LC tissues and related to patient survival, tumor size, and pathology. In addition, upregulation of PCAT19 hindered LC cell proliferation, miR-25-3p expression, and the activation of extracellular regulated protein kinases (ERK) 1/2, p38, and c-Jun N-terminal kinase (JNK), while facilitating LC cell apoptosis. Furthermore, upregulation of PCAT19 reversed the effects of Honokiol and anisomycin on promoting cell proliferation and inhibiting cell apoptosis. Collectively, our findings show that upregulated PCAT19 suppresses proliferation yet promotes the apoptosis of LC cells through modulating the miR-25-3p/MAP2K4 signaling axis.

Developments in the Antitumor Activity, Mechanisms of Action, Structural Modifications, and Structure-Activity Relationships of Steroidal Saponins

Steroidal saponins, a class of natural products formed by the combination of spirosteranes with sugars, are widely distributed in plants and have various biological activities, such as anti-tumor, anti-inflammatory, anti-bacterial, anti-Alzheimer's, anti-oxidation, etc. Particularly, extensive researches on the antitumor property of steroidal saponins have been received. Steroidal sapogenins, the aglycones of steroidal saponins, also have attracted much attention due to a vast range of pharmacological activities similar to steroidal saponins. In the past few years, structural modifications on the aglycones and sugar chains of steroidal saponins have been carried out and some achievements have been made. In this mini-review, the antitumor activity, action mechanisms, and structural modifications along with the structure-activity relationships of steroidal saponins and their derivatives are summarized.

The effect and mechanisms of melatonin on the proliferation and apoptosis of lung cancer cells

The aim of the present study was to observe the effects and mechianisms of melatonin on the proliferation and apoptosis of lung cancer (LC) cells. A549 cells were treated with a concentration gradient (0–100 μM) of melatonin for 24 hours, and cell viability was detected by XTT ((2,3-Bis-(2-methoxy-4-nitro-5-sulfophenyl) −2H-tetrazolium-5-carboxanilide)) colorimetry. Melatonin with a concentration of 50 μM was selected to interact with the LC cells for ten days, and then a colony formation assay was used to detect the proliferation of the LC cells. TUNEL (Terminal-deoxynucleoitidyl Transferase Mediated Nick End Labeling) staining was used to evaluate the amount of apoptosis in the two groups. Finally, Western blotting was used to detect the expression levels of related proteins in the p38MAP (mitogen-activated protein) signaling pathway. Meanwhile, another experiment, CCK-8 cell proliferation test, was conducted to detect the OD540 absorbance of LC cells at 24, 48, 72, and 96 hours. Melatonin inhibited the proliferation of LC cells in a concentration-dependent (5–100 μM) manner (P < 0.05), and inhibited the proliferation of LC cells in a time-dependent (0–96 hour) manner (P < 0.05). Melatonin (50 μM) could significantly inhibit the colony formation ability of LC cells (P < 0.05). The ratio of LC cells in the G0/G1 phase in the melatonin group increased, while the ratio of cells in the G2/M and S phase was significantly reduced (P < 0.05). Melatonin significantly promoted the apoptosis of LC cells (P < 0.05) and activate the phosphorylation of p38 (P < 0.05).

Pure drug nano-assemblies: A facile carrier-free nanoplatform for efficient cancer therapy

Nanoparticulate drug delivery systems (Nano-DDSs) have emerged as possible solution to the obstacles of anticancer drug delivery. However, the clinical outcomes and translation are restricted by several drawbacks, such as low drug loading, premature drug leakage and carrier-related toxicity. Recently, pure drug nano-assemblies (PDNAs), fabricated by the self-assembly or co-assembly of pure drug molecules, have attracted considerable attention. Their facile and reproducible preparation technique helps to remove the bottleneck of nanomedicines including quality control, scale-up production and clinical translation. Acting as both carriers and cargos, the carrier-free PDNAs have an ultra-high or even 100% drug loading. In addition, combination therapies based on PDNAs could possibly address the most intractable problems in cancer treatment, such as tumor metastasis and drug resistance. In the present review, the latest development of PDNAs for cancer treatment is overviewed. First, PDNAs are classified according to the composition of drug molecules, and the assembly mechanisms are discussed. Furthermore, the co-delivery of PDNAs for combination therapies is summarized, with special focus on the improvement of therapeutic outcomes. Finally, future prospects and challenges of PDNAs for efficient cancer therapy are spotlighted.

Saponins in Cancer Treatment: Current Progress and Future Prospects

Saponins are steroidal or triterpenoid glycoside that is distinguished by the soap-forming nature. Different saponins have been characterized and purified and are gaining attention in cancer chemotherapy. Saponins possess high structural diversity, which is linked to the anticancer activities. Several studies have reported the role of saponins in cancer and the mechanism of actions, including cell-cycle arrest, antioxidant activity, cellular invasion inhibition, induction of apoptosis and autophagy. Despite the extensive research and significant anticancer effects of saponins, there are currently no known FDA-approved saponin-based anticancer drugs. This can be attributed to a number of limitations, including toxicities and drug-likeness properties. Recent studies have explored options such as combination therapy and drug delivery systems to ensure increased efficacy and decreased toxicity in saponin. This review discusses the current knowledge on different saponins, their anticancer activity and mechanisms of action, as well as promising research within the last two decades and recommendations for future studies.

Natural Polyphyllins (I, II, D, VI, VII) Reverses Cancer Through Apoptosis, Autophagy, Mitophagy, Inflammation, and Necroptosis

Cancer is the second leading cause of mortality worldwide. Conventional therapies, including surgery, radiation, and chemotherapy, have limited success because of secondary resistance. Therefore, safe, non-resistant, less toxic, and convenient drugs are urgently required. Natural products (NPs), primarily sourced from medicinal plants, are ideal for cancer treatment because of their low toxicity and high success. NPs cure cancer by regulating different pathways, such as PI3K/AKT/mTOR, ER stress, JNK, Wnt, STAT3, MAPKs, NF-kB, MEK-ERK, inflammation, oxidative stress, apoptosis, autophagy, mitophagy, and necroptosis. Among the NPs, steroid saponins, including polyphyllins (I, II, D, VI, and VII), have potent pharmacological, analgesic, and anticancer activities for the induction of cytotoxicity. Recent research has demonstrated that polyphyllins (PPs) possess potent effects against different cancers through apoptosis, autophagy, inflammation, and necroptosis. This review summarizes the available studies on PPs against cancer to provide a basis for future research.

Synergy between vinorelbine and afatinib in the inhibition of non-small cell lung cancer progression by EGFR and p53 signaling pathways

Currently, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) were approved for the treatment of non-small cell lung cancer (NSCLC) patients harboring EGFR mutation. However, some lung cancer patients fail to respond and eventually develop drug resistance. Therefore, new therapeutic strategies are needed to improve the outcomes for substantial clinical benefit. Here we aimed to explore the combination of vinorelbine with the second EGFR-TKI afatinib in NSCLC cells with or without EGFR mutation. The three cells of H1975, HCC827, and H460 were assessed for the combination of vinorelbine and afatinib. Vinorelbine combined with afatinib synergistically inhibited the three lung cancer cells growth without aggravating adverse effect on the normal lung cells. The combination of low doses of vinorelbine and afatinib suppressed the cancer cell proliferation by cell colony formation assay and significantly induced cell apoptosis. The anti-apoptotic proteins Bcl-xL and Bcl-2 showed significant reduction after the drug combination treatment, while the pro-apoptotic protein Bax as well as apoptosis indicators cytochrome C and cleaved PARP were observed a notable increasing. EGFR downstream pathways including AKT, ERK, JNK, and p38 were highly active and p53 was inactive in the three lung cancer cells, favoring tumor growth. The low doses of vinorelbine plus afatinib blocked the phosphorylation of AKT, ERK, JNK, and p38, but restored the expression of p53. Our findings suggested that the combination of vinorelbine and afatinib could be recommended as a therapeutic regimen for treatment of NSCLC with or without EGFR mutation.

Effect of verapamil on the pharmacokinetics of hydroxycamptothecin and its potential mechanism

Context: Hydroxycamptothecin (HCPT) has antitumor activity in various cancers, but its poor bioavailability and efflux limit its clinical application. Verapamil has been demonstrated to improve the bioavailability of many drugs. However, the effect of verapamil on the pharmacokinetics of HCPT was not clear.Objective: The effect of verapamil on the pharmacokinetics of HCPT was investigated to clarify the drug-drug interaction between HCPT and verapamil.Materials and methods: The pharmacokinetic profiles of oral administration of HCPT (50 mg/kg) in two group of Sprague-Dawley rats (six rats each), with pre-treatment of verapamil (10 mg/kg/day) for 7 days were investigated, with the group without verapamil pre-treatment as control. Additionally, the metabolic stability and transport of HCPT in the presence or absence of verapamil were also investigated with the employment of the rat liver microsomes and Caco-2 cell transwell model.Results: Verapamil significantly increased the peak plasma concentration (from 91.97 ± 11.30 to 125.30 ± 13.50 ng/mL), and decrease the oral clearance (from 63.85 ± 10.79 to 32.95 ± 6.17 L/h/kg). The intrinsic clearance rate was also significantly decreased (from 39.49 ± 0.42 to 28.64 ± 0.30 μL/min/mg protein) by the preincubation of verapamil. The results of Caco-2 cell transwell experiments showed the efflux of HCPT was inhibited by verapamil, as the efflux ratio decreased from 1.82 to 1.21.Discussion and conclusions: The system exposure of HCPT was increased by verapamil. Verapamil may exert this effect through inhibiting the activity of CYP3A4 or P-gp, which are related to the metabolism and transport of HCPT.

Methylprednisolone potentiates tetrandrine pharmacodynamics against human T lymphoblastoid leukemia MOLT-4 cells via regulation of NF-κB activation and cell cycle transition

Low response to glucocorticoid (GC) predicts therapeutic failure in acute T lymphoblastic leukemia (T-ALL). The efficient and safe strategies are still required for the treatment of relapsed T-ALL. Our previous study revealed that tetrandrine induces apoptosis in human T lymphoblastoid leukemia cells possibly via activation of NF-κB. GCs are recognized as typical NF-κB inhibitors and are used for the treatment of T-ALL patients. In the present study, we examined whether methylprednisolone (MP) potentiates the cytotoxic effect of tetrandrine (TET) via NF-κB regulation by using human T lymphoblastoid leukemia MOLT-4 cells. WST-8 assay data showed that nM grade of MP increased cytotoxicity of TET against MOLT-4 cells in vitro. This effect seemed to be related to the potentiation of TET action by MP to induce apoptosis. Meanwhile, the combination also impeded the transition of cell cycle from G0/G1 phase to S phase. However, the regulation effect of this combination on cell cycle had no relationship with cyclin signaling pathway, since the drug-combination did not influence on the expression of cyclin A2/B1/D1 in MOLT-4 cells. On the other hand, the combination significantly inhibited the phosphorylation of NF-κB (p < 0.01). These results suggest that nM grade of MP potentiates the cytotoxic effect of TET possibly via regulation of NF-κB activation and "G0/G1 to S" phase transition in human T lymphoblastoid leukemia MOLT-4 cells. Combination of TET and MP may provide a new therapeutic strategy for relapsed T-ALL.

Tetrandrine enhances glucocorticoid receptor translocation possibly via inhibition of P-glycoprotein in daunorubicin-resistant human T lymphoblastoid leukemia cells

Glucocorticoids are used as anticancer and immunosuppressive agents, whereas glucocorticoid resistance has been observed in a significant fraction of patients due to overexpression of P-glycoprotein encoded by multi-drug resistance-1 gene. Tetrandrine is a bisbenzylisoquinoline alkaloid isolated from traditional herb Fangji. According to our previous report, tetrandrine potentiated glucocorticoid pharmacodynamics partially via inhibiting P-glycoprotein function. In the present study, we investigated whether glucocorticoid receptor translocation was influenced indirectly by tetrandrine via P-glycoprotein inhibition, using human T lymphoblastoid leukemia MOLT-4 cell line with little P-glycoprotein expression and its multidrug resistant sub-line MOLT-4/DNR exhibiting a large amount of P-glycoprotein. Molecular mechanism investigation suggested that overexpressed P-glycoprotein weakened the glucocorticoid receptor translocation in MOLT-4/DNR cells comparing with the parent MOLT-4 cells. Our data also suggested that tetrandrine enhanced nuclear glucocorticoid receptor translocation in MOLT-4/DNR cells indirectly by dual influences on P-glycoprotein, inhibiting the efflux function and downregulating the protein expression. Therefore, tetrandrine potentiated the cytotoxic effect of methylprednisolone against MOLT-4/DNR cells with less effects on MOLT-4 cells. These effects of tetrandrine were suggested to be beneficial for the treatment of glucocorticoid resistant diseases induced by the overexpression of P-glycoprotein.

Effect of Ganoderma applanatum polysaccharides on MAPK/ERK pathway affecting autophagy in breast cancer MCF-7 cells

Fungal polysaccharides have become hotspots in the field of health foods due to their antitumor activity in recent years. In this experiment, antitumor effect of the medicinal fungus Ganoderma applanatum polysaccharide (GAP) was investigated in human breast cancer MCF-7 cells, as well as the molecular mechanism of its effect on autophagy. Results showed that GAP contains three polysaccharides with molecular weights of 6.36 × 10⁵ Da, 4.25 × 10⁵ Da, and 2.53 × 10⁵ Da and which composed of rhamnose, glucose, arabinose, fucose in the molar ratio of 1:22:16.1:3.2. GAP inhibited the proliferation and migration of MCF-7 cells in a time-dose-dependent manner, the maximum inhibition rate reached 50.2% at 500 μg/mL in 48 h. Flow cytometry analysis showed that GAP could induce apoptosis, treatment of cells with GAP could result in up-regulation of gene and protein levels of autophagy-associated markers LC3 and Beclin-1; addition of autocrine late inhibitor CQ significantly raised the protein expression level of LC3II. The mitogen-activated protein kinases (MAPK) signaling pathway was not only related to the apoptotic pathway but also to the autophagy pathway; Western blot analysis showed that MAPK signaling pathway is involved in GAP-induced autophagy in MCF-7 cells. Detection of the relevant signaling pathway protein showed that the expression of p-ERK1/2 protein was down-regulated, however the expression of p-p38 and p-JNK protein was up-regulated. These results indicate that GAP could induce early autophagy in MCF-7 cells via the MAPK/ERK pathway. In conclusion, GAP showed strong antitumor activity by inducing apoptosis and autophagy through MAPK signaling pathway in MCF-7 cells, suggesting the molecular mechanism of fungal polysaccharide on its antitumor activity.

The biosynthesis of camptothecin derivatives by Camptotheca acuminata seedlings

10-hydroxycamptothecin and 9-methoxycamptothecin, naturally occurring camptothecin derivatives, are reportedly present in Camptotheca acuminata with a powerful cytotoxic effect and strong antitumor activity. In this paper, we studied the derivatization reaction of camptothecin catalyzed by C. acuminata seedlings. HPLC traced the reaction between exogenous camptothecin and C. acuminata seedlings. The results showed that the exogenous camptothecin was converted into 10-hydroxycamptothecin and 9-methoxycamptothecin by the tender roots and stems of C. acuminata seedlings, which would be a new method for the synthesis of two camptothecin derivatives.

MicroRNA-188-5p promotes apoptosis and inhibits cell proliferation of breast cancer cells via the MAPK signaling pathway by targeting Rap2c

Breast cancer is a common malignancy that is highly lethal with poor survival rates and immature therapeutics that urgently needs more effective and efficient therapies. MicroRNAs are intrinsically involved in different cancer remedies, but their mechanism in breast cancer has not been elucidated for prospective treatment. The function and mechanism of microRNA-188-5p (miR-188) have not been thoroughly investigated in breast cancer. In our study, we found that the expression of miR-188 in breast cancer tissues was obviously reduced. Our findings also revealed the abnormal overexpression of miR-188 in 4T1 and MCF-7 cells significantly suppressed cell proliferation and migration and also enhanced apoptosis. miR-188 induced cell cycle arrest in the G1 phase. To illuminate the molecular mechanism of miR-188, Rap2c was screened as a single target gene by bioinformatics database analysis and was further confirmed by dual-luciferase assay. Moreover, Rap2c was found to be a vital molecular switch for the mitogen-activated protein kinase signaling pathway in tumor progression by decreasing apoptosis and promoting proliferation and migration. In conclusion, our results revealed that miR-188 is a cancer progression suppressor and a promising future target for breast cancer therapy.

Polyphyllin VI induces apoptosis and autophagy in human osteosarcoma cells by modulation of ROS/JNK activation

Purpose

Polyphyllin VI, a main active saponin isolated from traditional medicinal plant Paris polyphylla, has exhibited antitumor activities in several cancer cell lines. In the present study, we investigated the antitumor effect of Polyphyllin VI against human osteosarcoma cells (U2OS) and the underlying molecular mechanisms.

Methods

The U2OS cell lines were used to determine the antiproliferative effect of Polyphyllin VI by CCK8 assay. Cell cycle was analyzed by flow cytometry. The Polyphyllin VI-induced apoptosis was determined by Annexin V-APC/7-AAD apoptosis detection kit and JC-1 staining. Meanwhile, the autophagy was determined by acridine orange staining. The apoptosis and autophagy-related proteins were monitored by Western blot assay. Subsequently, intracellular hydrogen peroxide (H₂O₂) and the activation of ROS/JNK pathway were detected.

Results

Polyphyllin VI could potently inhibit cell proliferation by causing G2/M phase arrest. Polyphyllin VI induced mitochondria-mediated apoptosis with the upregulation of proapoptotic proteins Bax and poly ADP-ribose polymerase, and downregulation of antiapoptotic protein Bcl-2 in U2OS cells. Concomitantly, Polyphyllin VI provoked autophagy with the upregulation of critical Atg proteins and accumulation of LC3B-II. Intracellular H₂O₂ production was triggered upon exposure to Polyphyllin VI, which could be blocked by ROS scavenger. Polyphyllin VI dramatically promoted JNK phosphorylation, whereas it decreased the levels of phospho-p38 and ERK.

Conclusion

Our results reveal that Polyphyllin VI may effectively induce apoptosis and autophagy to suppress cell growth via ROS/JNK activation in U2OS cells, suggesting that Polyphyllin VI is a potential drug candidate for the treatment of osteosarcomas.

Recent nanotechnological interventions targeting PI3K/Akt/mTOR pathway: A focus on breast cancer

Breast cancer is the major cause of deaths in women worldwide. Detection and treatment of breast cancer at earlier stages of the disease has shown encouraging results. Modern genomic technologies facilitated several therapeutic options however the diagnosis of the disease at an advanced stage claim more deaths. Therefore more research directed towards genomics and proteomics into this area may lead to novel biomarkers thereby enhancing the survival rates in breast cancer patients. Phosphoinositide-3-kinase/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway was shown to be hyperactivated in most of the breast carcinomas resulting in excessive growth, proliferation, and tumor development. Development of nanotechnology has provided many interesting avenues to target the PI3K/Akt/mTOR pathway both at the pre-clinical and clinical stages. Therefore, the current review summarizes the underlying mechanism and the importance of targeting PI3K/Akt/mTOR pathway, novel biomarkers and use of nanotechnological interventions in breast cancer.

Hepatocellular Toxicity of Paris Saponins I, II, VI and VII on Two Kinds of Hepatocytes-HL-7702 and HepaRG Cells, and the Underlying Mechanisms

Rhizoma paridis is a popularly-used Chinese medicine in clinics, based on the pharmacodynamic properties of its saponin components. The four main saponins in Rhizoma paridis are designated saponins I, II, VI, and VII. At present, much attention is focused on the anticancer effect of Rhizoma paridis which is manifested in its cytotoxicity to various cancer cells. The purpose of this study was to investigate the hepatocellular toxicities of the four saponins in Rhizoma paridis and the relative intensities of their cytotoxic effects. It was found that the four saponins were cytotoxic to two types of hepatocytes-HL-7702 and HepaRG cells. The cytotoxicities of the four saponins to the two cell models were compared. One of the most cytotoxic saponins was Rhizoma paridis saponin I (PSI). This was used to determine the mechanism of hepatocellular toxicity. Results from MTT assays demonstrated that the four saponins induced apoptosis of the two hepatocyte models in a dose-dependent and time-dependent manner. In addition, fluorescent 4′,6-diamidino-2-phenylindole (DAPI) staining was used to observe the morphological changes of HepaRG cells after saponin administration. Further, as the concentration increased, PSI-induced lactate dehydrogenase (LDH) release from HepaRG cells increased gradually. In addition, PSI enhanced the levels of reactive oxygen species (ROS) and blocked the S and G2 phases of the cell cycle in HepaRG cells. A western blot indicated that PSI upregulated the protein expression levels of p53, p21, and Fas. Furthermore, the PSI-induced changes in the p53 protein increased the Bax/bcl-2 ratio, resulting in enhancement of the release of mitochondrial cytochrome c, activation of caspases-3, -8, and -9, poly-ADP ribose polymerase (PARP), and ultimately apoptosis. Increased Fas protein activated caspase-8, which led to the activation of caspase-3 and its downstream PARP protein, resulting in cell apoptosis. These results indicate that PSI induced apoptosis in HepaRG cells through activation of ROS and death receptor pathways. The results obtained in this study suggest that the hepatocellular toxicity of saponins in Rhizoma paridis should be considered during the clinical application of this drug. In addition, they provide a reference for future anti-cancer studies on Rhizoma paridis.

Mytoxin B and Myrothecine A Induce Apoptosis in Human Hepatocarcinoma Cell Line SMMC-7721 via PI3K/Akt Signaling Pathway

Trichothecene macrolides comprise a class of valuable leading compounds in developing anticancer drugs, however, there are few reports concerning their anticancer mechanisms, especially the anticancer mechanism of the 10,13-cyclotrichothecane derivatives that are found mainly in symbiotic fungi. In vitro anticancer activity of two trichothecene macrolides mytoxin B and myrothecine A against the human hepatocarcinoma cell line SMMC-7721 was investigated in the present study. MTT assay showed that mytoxin B and myrothecine A inhibited the proliferation of SMMC-7721 cells in dose- and time-dependent manners. Annexin V-FITC/PI dual staining assay revealed that mytoxin B and myrothecine A both could induce SMMC-7721 cells apoptosis in a dose-dependent manner. The decreased expression level of anti-apoptotic protein Bcl-2 and the increased expression level of pro-apoptotic protein Bax were observed apparently in Western blot analysis. The reduced ratio of Bcl-2/Bax further confirmed the apoptosis-inducing effect of mytoxin B and myrothecine A on SMMC-7721 cells. Moreover, the expression levels of caspases-3, -8, and -9, and cleaved caspases-3, -8, and -9 were all upregulated in both mytoxin B and myrothecine A-treated cells in Western blot analysis, which indicated that both compounds might induce SMMC-7721 cells apoptosis through not only the death receptor pathway but also the mitochondrial pathway. Finally, mytoxin B and myrothecine A were found to reduce the activity of PI3K/Akt signaling pathway that was similar to the effect of LY294002 (a potent and specific PI3K inhibitor), suggesting that both mytoxin B and myrothecine A might induce SMMC-7721 cells apoptosis via PI3K/Akt pathway.

Dioscin-6'-O-acetate inhibits lung cancer cell proliferation via inducing cell cycle arrest and caspase-dependent apoptosis

BACKGROUND

Lung cancer is the leading cause of global cancer-related mortality. Dioscin-6'-O-acetate (DA), a novel natural steroidal saponin, was firstly isolated from the rhizomes of Dioscorea althaeoides R. Knuth. Until now, there were no studies on its pharmacological activities.

PURPOSE

Here, we investigated the growth inhibitory effect and explored the underlying molecular mechanisms of DA against lung cancer cells.

METHODS/STUDY DESIGNS

NSCLC H460, H1299, H520 cells and SCLC H446 cells were treated with DA. To display the cytotoxic effects and possible mechanism of DA on these cells, MTT assay, flow cytometry and western blot analysis were carried out.

RESULTS

Our results showed that DA exerted strong anti-proliferative activity against lung cancer cells in a concentration- and time-dependent manner. Flow cytometry demonstrated DA induced the cell cycle arrest at S-phase (NCI-H460, NCI-H1299, NCI-H520) or G1-phase (NCI-H446), caused cellular apoptosis, generation of reactive oxygen species (ROS) and loss of mitochondrial membrane potential. Western blotting analysis showed DA treatment increased the levels of caspase 3, 8, 9, Bax, p21, p53, phosphorylated JNK and p38 MAPK and markedly decreased the expression of Bcl-2, p-ERK, p-PI3K, p-AKT and NF-κB. Blockade of caspases with Z-VAD-FMK converted apoptosis-related proteins. Suppression of p53 with pifithrin-α (PFT) attenuated cell cycle-related protein. Inhibition of ROS with N-acetyl-cysteine (NAC) adjusted apoptosis-related proteins and phosphorylated MAPK and PI3K, as well as NF-κB.

CONCLUSION

Overall, our study indicated that DA suppressed lung cancer cells proliferation via inducing cell-cycle arrest and enhancing caspase-dependent apoptosis, at least partly, through ROS-mediated PI3K/AKT, MAPK and NF-κB signaling pathways.

Advances in the antitumor activities and mechanisms of action of steroidal saponins

The steroidal saponins are one of the saponin types that exist in an unbound state and have various pharmacological activities, such as anticancer, anti-inflammatory, antiviral, antibacterial and nerves-calming properties. Cancer is a growing health problem worldwide. Significant progress has been made to understand the antitumor effects of steroidal saponins in recent years. According to reported findings, steroidal saponins exert various antitumor activities, such as inhibiting proliferation, inducing apoptosis and autophagy, and regulating the tumor microenvironment, through multiple related signaling pathways. This article focuses on the advances in domestic and foreign studies on the antitumor activity and mechanism of actions of steroidal saponins in the last five years to provide a scientific basis and research ideas for further development and clinical application of steroidal saponins.

Astragalus polysaccharide combined with 10-hydroxycamptothecin inhibits metastasis in non-small cell lung carcinoma cell lines via the MAP4K3/mTOR signaling pathway

Non‑small cell lung carcinoma (NSCLC) is a life‑threatening malignancy. The level of the cell growth regulator mitogen‑activated protein kinase kinase kinase kinase 3 (MAP4K3) has been shown to be correlated with a high risk of NSCLC recurrence and poor recurrence‑free survival rate. The present study examined the effects of Astragalus polysaccharide (APS) and 10‑hydroxycamptothecin (HCPT), which are associated with marked suppression and dephosphorylation of the MAP4K3/mammalian target of rapamycin (mTOR) signaling pathway, in the H1299 NSCLC cell line. APS and HCPT decreased H1299 cell viability, induced apoptosis and altered the cell cycle stages, as evaluated using an 3‑(4,5‑dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazolium bromide assay and flow cytometric analysis. Furthermore, APS increased the expression of apoptosis‑associated genes B‑cell lymphoma 2 (Bcl‑2) and Bcl‑2‑associated X protein (BAX), of proteases cysteine‑aspartic acid protease (caspase)‑3 and ‑9, and of cytochrome c. HCPT promoted autophagy in H1299 cells, with concomitant suppression of the expression of MAP4K3 and downregulation of mTOR signaling. Notably, combination treatment with the two agents reduced the migration and invasion of H1299 cells compared with the single treatments. It was also demonstrated that the overexpression of MAP4K3 promoted the migration and invasion of H1299 cells, and that the kinase activity was essential to this. These findings suggested that MAP4K3 may be an attractive target for the treatment of NSCLC.

Locally Deployable Nanofiber Patch for Sequential Drug Delivery in Treatment of Primary and Advanced Orthotopic Hepatomas

With unsatisfactory effects of systemic chemotherapy for treatment of unresectable or advanced hepatoma, local and sustained delivery of chemotherapeutic agents is becoming a promising solution. The in situ administered platforms increase the drug concentrations in tumor regions, decrease the side effects to organs, prevent the damage to vascular endothelium, and reduce the frequency of drug administration. The prevalent strategy based on minimally invasive transarterial chemoembolization oftentimes induces upper gastrointestinal hemorrhage, liver failure, and liver abscess. In addition, integrating various antitumor drugs in one platform, especially the drugs with different hydrophilic/hydrophobic properties, and achieving sustained and/or sequential release profiles to synergistically inhibit cancer progression remain challenging. In this study, a local drug delivery system made of an emulsion-electrospun polymer patch was developed, which contained hydrophobic 10-hydroxycamptothecin (HCPT) and hydrophilic tea polyphenols (TP) in the shell and core of the nanofiber, respectively. Due to this core-sheath structure, HCPT and TP exhibited sustained and sequential releases first with HCPT followed by TP. HCPT was used to suppress the proliferation and malignant transformation of hepatoma, whereas TP was aimed to decrease the levels of oxygen free radicals and further prevent the invasion and metastasis of tumor cells. Our study presented the potential superiority of this class of core-sheath structured nanofiber membranes in localized treatment of both primary and advanced orthotopic hepatomas.

Camptothecin inhibits the progression of NPC by regulating TGF-β-induced activation of the PI3K/AKT signaling pathway

Nasopharyngeal carcinoma (NPC) is a type of cancer that is characterized by increased invasiveness, metastatic potential and tumor recurrence. Camptothecin has been demonstrated to exhibit anticancer activity. However, the potential underlying molecular mechanisms mediated by camptothecin in NPC cells remain elusive. In the present study, the efficacy of camptothecin for NPC was investigated in vitro and in vivo. Additionally, the potential signaling pathway mediated by camptothecin in NPC cells was also examined. The results indicated that the viability and aggressiveness of NPC cells were suppressed by camptothecin treatment in a dose-dependent manner. Camptothecin administration downregulated the expression levels of cell-cycle-associated proteins including cyclin 1, cyclin-dependent kinase (CDK)1 and CDK2 in NPC cells. Expression levels of migration-associated proteins including vimentin, fibronectin and epithelial cadherin were regulated by camptothecin treatment in NPC cells. Additionally, camptothecin inhibited the expression of transforming growth factor-β (TGF-β), phosphoinositide 3-kinase (PI3K) and protein kinase B (AKT), whereas TGF-β overexpression abrogated camptothecin-mediated inhibition of PI3K and AKT expression and camptothecin-mediated inhibition of the viability and aggressiveness of NPC cells. Camptothecin significantly inhibited tumor growth and increased survival times in a mouse model of cancer. In conclusion, these results indicate that camptothecin treatment may inhibit the viability of NPC cells and aggressiveness by regulating the TGF-β-induced PI3K/AKT signaling pathways, which in turn may be a potential molecular target for the treatment of NPC.

Self-Assembled Nanoparticles Platform Based on Pectin-Dihydroartemisinin Conjugates for Codelivery of Anticancer Drugs

Natural pectin is an important carrier for delivering drugs in biomedical research, however, there are only a few reports on the preparation of pectin nanoparticles, especially a particle size of below 100 nm with high yield. Here we design pectin-dihydroartemisinin/hydrooxycampothecin nanoparticles (PDC-H NPs) through a self-assembly method. The prepared PDC-H NPs contained hydrophilic part of pectin and hydrophobic anticancer drugs of dihydroartemisinin and hydroxycamptothecin, which could increase drug loading, improve water solubility, and achieve controlled release of drugs. The results indicated that the particle size of PDC-H NPs was about 70 nm, drug-loaded efficiency of DHA was 20.33 wt %, and encapsulation efficiency of HCPT was 14.11 wt %. PDC-H NPs exhibited a higher cytotoxicity, the blood retention time of PDC-H NPs was 4.8-fold longer than DHA and was 6.8-fold longer than HCPT. In addition, effective cellular uptake exhibited an obvious synergistic effect compared with DHA and HCPT. 4T1 tumor-bearing mice also showed a higher survival rate than free DHA and free HCPT. The result show that the self-assembled PDC-H NPs is a promising anticancer drug for codelivery.

Dual-specificity phosphatase 6 (DUSP6): a review of its molecular characteristics and clinical relevance in cancer

Mitogen-activated protein kinases (MAPKs) are the main regulators of cellular proliferation, growth, and survival in physiological or pathological conditions. Aberrant MAPK signaling plays a pivotal role in carcinogenesis, which leads to development and progression of human cancer. Dual-specificity phosphatase 6 (DUSP6), a member of the MAPK phosphatase family, interacts with specifically targeted extracellular signal-regulated kinase 1/2 via negative feedback regulation in the MAPK pathway of mammalian cells. This phosphatase functions in a dual manner, pro-oncogenic or tumor-suppressive, depending on the type of cancer. To date, the tumor-suppressive role of DUSP6 has been demonstrated in pancreatic cancer, non-small cell lung cancer, esophageal squamous cell and nasopharyngeal carcinoma, and ovarian cancer. Its pro-oncogenic role has been observed in human glioblastoma, thyroid carcinoma, breast cancer, and acute myeloid carcinoma. Both roles of DUSP6 have been documented in malignant melanoma depending on the histological subtype of the cancer. Loss- or gain-of-function effects of DUSP6 in these cancers highlights the significance of this phosphatase in carcinogenesis. Development of methods that use the DUSP6 gene as a therapeutic target for cancer treatment or as a prognostic factor for diagnosis and evaluation of cancer treatment outcome has great potential. This review focuses on molecular characteristics of the DUSP6 gene and its role in cancers in the purview of development, progression, and cancer treatment outcome.

Gimatecan exerts potent antitumor activity against gastric cancer in vitro and in vivo via AKT and MAPK signaling pathways

Background

We investigated antitumor activity and underlying mechanisms of DNA topoisomerase I (TopI) inhibitor gimatecan and irinotecan in gastric cancer (GC) in vitro cell lines and in vivo patient-derived xenograft (PDX) models.

Methods

GC cell lines SNU-1, HGC27, MGC803 and NCI-N87 were used to evaluate cell viability and apoptosis after gimatecan or irinotecan treatment, using a cell proliferation assay and flow cytometry, respectively. DNA TopI expression and critical molecules of PI3K/AKT, MAPK and apoptosis signaling pathways were analyzed with western blot. For in vivo studies, five PDXs models were treated with gimatecan or irinotecan to assess its antitumor activity. Immunohistochemistry staining of Ki-67 was performed after mice were sacrificed.

Results

Gimatecan inhibited the proliferation of GC cells in vitro in a dose- and time-dependent manner by inducing apoptosis, and gimatecan had greater inhibitory effects than irinotecan. In addition, both gimatecan and irinotecan demonstrated significant tumor growth inhibition in in vivo PDX models. Gimatecan treatment significantly inhibited the expression of DNA TopI, phosphorylated AKT (pAKT), phosphorylated MEK (pMEK) and phosphorylated ERK (pERK). Meanwhile, gimatecan could also activate the JNK2 and p38 MAPK pathway as indicated by upregulation of phosphorylated p38 MAPK (p-p38) and phosphorylated JNK2 (pJNK2).

Conclusions

For the first time, we have shown that the antitumor activity of gimatecan in GC via suppressing AKT and ERK pathway and activating JNK2 and p38 MAPK pathway, which indicated that gimatecan might be an alternative to irinotecan in the treatment of GC.

Electronic supplementary material

The online version of this article (10.1186/s12967-017-1360-z) contains supplementary material, which is available to authorized users.

Self-Assembled Polyprodrug Amphiphile for Subcutaneous Xenograft Tumor Inhibition with Prolonged Acting Time In Vivo

Polymeric drug delivery system termed as "polyprodrug amphiphile" poly(2-methylacryloyloxyethyl phosphorylcholine)-b-poly(10-hydroxy-camptothecin methacrylate (pMPC-b-pHCPT) is developed for the prolonged-acting cancer therapy. It is obtained by two-step reversible addition-fragmentation chain transfer polymerization of zwitterionic monomer MPC and an esterase-responsive polymerizable prodrug methacrylic anhydride-CPT, respectively. This diblock polymer is composed of both antifouling (pMPC) and bioactive (pHCPT) segments and the drug is designed as a building block to construct the polymer skeleton directly. Due to its distinct amphiphilicity, the polymer can self-assemble into micelles with different dynamic sizes by facilely tuning the ratio of MPC/HCPT under physiological conditions. The outer pMPC shell is superhydrophilic to form dense hydrate layer preventing the nanosystem from unwanted nonspecific protein adsorption, which is the main lead cause of the rapid clearance of nanoparticles in vivo, thus facilitating the accumulation of drugs in tumor sites via enhanced permeability and retention effect. The configuration of the polyprodrug amphiphile is confirmed by several measurements. The resistance to albumin adsorption, prolonged plasma retention time, accumulation in tumor sites, and anticancer activity of the micelles is also investigated in vitro and in vivo. This novel amphiphile can be expected as a promising agent for the passive targeted prolonged-acting cancer therapy.

Glycosylated Triterpenoids as Endosomal Escape Enhancers in Targeted Tumor Therapies

Protein-based targeted toxins play an increasingly important role in targeted tumor therapies. In spite of their high intrinsic toxicity, their efficacy in animal models is low. A major reason for this is the limited entry of the toxin into the cytosol of the target cell, which is required to mediate the fatal effect. Target receptor bound and internalized toxins are mostly either recycled back to the cell surface or lysosomally degraded. This might explain why no antibody-targeted protein toxin has been approved for tumor therapeutic applications by the authorities to date although more than 500 targeted toxins have been developed within the last decades. To overcome the problem of insufficient endosomal escape, a number of strategies that make use of diverse chemicals, cell-penetrating or fusogenic peptides, and light-induced techniques were designed to weaken the membrane integrity of endosomes. This review focuses on glycosylated triterpenoids as endosomal escape enhancers and throws light on their structure, the mechanism of action, and on their efficacy in cell culture and animal models. Obstacles, challenges, opportunities, and future prospects are discussed.

Self-assembled nanoparticles based on a carboxymethylcellulose–ursolic acid conjugate for anticancer combination therapy

A new self-assembled nanoparticle platform based on a carboxymethylcellulose (CMC)–ursolic acid (UA) conjugate is presented for the first time.

Synthesis and antitumor activity of novel substituted uracil-1'(N)-acetic acid ester derivatives of 20(S)-camptothecins

A series of novel substituted uracil-1'(N)-acetic acid esters (6-20) of camptothecins (CPTs) were synthesized by the acylation method. These new compounds were evaluated for in vitro antitumor activity against tumor cell lines, A549, Bel7402, BGC-823, HCT-8 and A2780. In vitro results showed that most of the derivatives exhibited comparable or superior cytotoxicity compare to CPT (1) and topotecan (TPT, 2), with 12 and 13 possessing the best efficacy. Four compounds, 9, 12, 13 and 16, were selected to be evaluated for in vivo antitumor activity against H₂₂, BGC-823 and Bel-7402 in mice. In vivo testing results indicated that 12 and 13 had antitumor activity against mouse liver carcinoma H₂₂ close to Paclitaxel and cyclophosphamide. 12 had similar antitumor activity against human gastric carcinoma BGC-823 in nude mice compared to irinotecan (3) and possessed better antitumor activity against human hepatocarcinoma Bel-7402 in nude mice than 2. It is also discovered that 12 showed a similar mechanism but better inhibitory activity on topoisomerase I (Topo I) compared to 2. These findings indicate that 20(S)-O-fluorouracil-1'(N)-acetic acid ester derivative of CPTs, 12, could be developed as an antitumor drug candidate for clinical trial.