Deciphering anoikis resistance and identifying prognostic biomarkers in clear cell renal cell carcinoma epithelial cells

This study tackles the persistent prognostic and management challenges of clear cell renal cell carcinoma (ccRCC), despite advancements in multimodal therapies. Focusing on anoikis, a critical form of programmed cell death in tumor progression and metastasis, we investigated its resistance in cancer evolution. Using single-cell RNA sequencing from seven ccRCC patients, we assessed the impact of anoikis-related genes (ARGs) and identified differentially expressed genes (DEGs) in Anoikis-related epithelial subclusters (ARESs). Additionally, six ccRCC RNA microarray datasets from the GEO database were analyzed for robust DEGs. A novel risk prognostic model was developed through LASSO and multivariate Cox regression, validated using BEST, ULCAN, and RT-PCR. The study included functional enrichment, immune infiltration analysis in the tumor microenvironment (TME), and drug sensitivity assessments, leading to a predictive nomogram integrating clinical parameters. Results highlighted dynamic ARG expression patterns and enhanced intercellular interactions in ARESs, with significant KEGG pathway enrichment in MYC + Epithelial subclusters indicating enhanced anoikis resistance. Additionally, all ARESs were identified in the spatial context, and their locational relationships were explored. Three key prognostic genes-TIMP1, PECAM1, and CDKN1A-were identified, with the high-risk group showing greater immune infiltration and anoikis resistance, linked to poorer prognosis. This study offers a novel ccRCC risk signature, providing innovative approaches for patient management, prognosis, and personalized treatment.

Platycodin D induces apoptosis via regulating MAPK pathway and promotes autophagy in colon cancer cell

Platycodin D (PD) is the main component of triterpene saponins found in Platycodi radix. In this study, we observed a decrease in cell viability, an increase in apoptotic bodies, and an increase in the rate of apoptosis. Also, we observed an increase in cleaved PARP and Bax, a decrease in Bcl-2, and p-ERK, and an increase in p-p38 and p-JNK. Furthermore, a change in cell viability and the expression of p-p38, Bax, and Bcl-2 using the p38 inhibitor revealed a decrease in p-p38 and Bax and an increase in Bcl-2 in the inhibitor treatment group. In addition, we observed an increase in vacuole formation through morphological changes and an increase in acidic vesicular organelles (AVOs). We also observed an increase in the expression of beclin 1, LC 3-I, and -II. There was no significant decrease in cell viability in the group treated with 3-MA, but a decrease in cell viability was noted in the group treated with HCQ. HCQ treatment resulted in an increase in Bax and a decrease in Bcl-2. These findings reveal that in HT-29 colon cancer cells, PD induces apoptosis through the MAPK pathway, thereby exerting anticancer effects. Moreover, autophagy caused by PD inhibits apoptosis by protecting the cells.

Platycodin D induces apoptotic cell death through PI3K/AKT and MAPK/ERK pathways and synergizes with venetoclax in acute myeloid leukemia

Acute myeloid leukemia (AML) is a highly heterogeneous and rapidly progressive hematopoietic neoplasm characterized by frequent relapses and variable prognoses. The development of new treatment options, therefore, is of crucial importance. Platycodin D (PD) is a triterpenoid saponin, extracted from the roots of the traditional Chinese herbal medicine Platycodon grandiflorum (Jacq.) A. DC., which has been reported to exhibit therapeutic potential against a broad range of cancers. Although the effects of PD on AML remain unclear, in the present study, we observed a concentration-dependent reduction in the viability of multiple human AML cell lines in response to treatment with PD. In addition to triggering mitochondria-dependent apoptosis via the upregulation of BAK and BIM, treatment with PD also induced cell cycle arrest at the G0/G1 phase. Western blot analyses revealed marked suppression of the phosphorylation of protein kinase B (AKT), glycogen synthase kinase-3β, ribosomal protein S6, and extracellular signal-regulated kinase (ERK) by PD, in turn implying the participation of the phosphoinositide 3-kinase (PI3K)/AKT and mitogen-activated protein kinase (MAPK)/ERK pathways. Pre-incubation with LY294002, MK2206, AR-A014418, or U0126 was consistently found to significantly aggravate PD-induced inhibition of viability. Additionally, PD combined with the B-cell lymphoma 2 (BCL2) inhibitor venetoclax elicited synergistically enhanced cytotoxic effects. The anti-leukemic activity of PD was further validated using primary samples from de novo AML patients. Given the results of the present study, PD may be a potent therapeutic candidate for the treatment of AML.

Regulation of anoikis by extrinsic death receptor pathways

Metastatic cancer cells can develop anoikis resistance in the absence of substrate attachment and survive to fight tumors. Anoikis is mediated by endogenous mitochondria-dependent and exogenous death receptor pathways, and studies have shown that caspase-8-dependent external pathways appear to be more important than the activity of the intrinsic pathways. This paper reviews the regulation of anoikis by external pathways mediated by death receptors. Different death receptors bind to different ligands to activate downstream caspases. The possible mechanisms of Fas-associated death domain (FADD) recruitment by Fas and TNF receptor 1 associated-death domain (TRADD) recruitment by tumor necrosis factor receptor 1 (TNFR1), and DR4- and DR5-associated FADD to induce downstream caspase activation and regulate anoikis were reviewed. This review highlights the possible mechanism of the death receptor pathway mediation of anoikis and provides new insights and research directions for studying tumor metastasis mechanisms. Video Abstract.

Natural products targeting signaling pathways associated with regulated cell death in gastric cancer: Recent advances and perspectives

Gastric cancer (GC) is one of the most serious gastrointestinal malignancies with high morbidity and mortality. The complexity of GC process lies in the multi-phenotypic linkage regulation, in which regulatory cell death (RCD) is the core link, which largely dominates the fate of GC cells and becomes a key determinant of GC development and prognosis. In recent years, increasing evidence has been reported that natural products can prevent and inhibit the development of GC by regulating RCDs, showing great therapeutic potential. In order to further clarify its key regulatory characteristics, this review focused on specific expressions of RCDs, combined with a variety of signaling pathways and their crosstalk characteristics, sorted out the key targets and action rules of natural products targeting RCD. It is highlighted that a variety of core biological pathways and core targets are involved in the decision of GC cell fate, including the PI3K/Akt signaling pathway, MAPK-related signaling pathways, p53 signaling pathway, ER stress, Caspase-8, gasdermin D (GSDMD), and so on. Moreover, natural products target the crosstalk of different RCDs by modulating above signaling pathways. Taken together, these findings suggest that targeting various RCDs in GC with natural products is a promising strategy, providing a reference for further clarifying the molecular mechanism of natural products treating GC, which warrants further investigations in this area.

Platycodin D induces proliferation inhibition and mitochondrial apoptosis in diffuse large B-cell lymphoma

Patients with diffuse large B-cell lymphoma (DLBCL) have unsatisfactory outcomes especially when relapse occurs after initial chemotherapy. Platycodin D (PD), a triterpenoid saponin isolated from the root of Platycodon grandiflorum (Jacq.) A. DC., has demonstrated potent anti-cancer activities. So far, however, information regarding the effect of PD on malignant lymphoma remains unavailable. In the present study, we showed that PD dose-dependently inhibited the viability of a serial of established DLBCL cell lines representing different molecular subtypes, and their sensitivities to PD were comparable. Mitochondrial dysfunction and subsequent intrinsic apoptosis were induced by PD, as indicated by the loss of mitochondrial membrane potential and the increase in the percentage of Annexin Ⅴ positive cells. Mechanistically, PD treatment downregulated expression levels of anti-apoptotic proteins including MCL-1, BCL-2, and BCL-XL, while upregulated the expression level of pro-apoptotic protein BAK, followed by the cleavage of PARP. Moreover, PD synergistically enhanced the cytotoxicity of BCL-2 inhibitor venetoclax. In a SUDHL-4-derived xenograft mouse model, PD administration significantly constrained the tumor growth without obvious side effects. Therefore, our results provided new insights into the role of PD in lymphoma therapy.

The pharmacology and mechanisms of platycodin D, an active triterpenoid saponin from Platycodon grandiflorus

Chinese doctors widely prescribed Platycodon grandiflorus A. DC. (PG) to treat lung carbuncles in ancient China. Modern clinical experiences have demonstrated that PG plays a crucial role in treating chronic pharyngitis, plum pneumonia, pneumoconiosis, acute and chronic laryngitis, and so forth. Additionally, PG is a food with a long history in China, Japan, and Korea. Furthermore, Platycodin D (PLD), an oleanane-type triterpenoid saponin, is one of the active substances in PG. PLD has been revealed to have anti-inflammatory, anti-viral, anti-oxidation, anti-obesity, anticoagulant, spermicidal, anti-tumor etc., activities. And the mechanism of the effects draws lots of attention, with various signaling pathways involved in these processes. Additionally, research on PLD’s pharmacokinetics and extraction processes is under study. The bioavailability of PLD could be improved by being prescribed with Glycyrrhiza uralensis Fisch. or by creating a new dosage form. PLD has been recently considered to have the potential to be a solubilizer or an immunologic adjuvant. Meanwhile, PLD was discovered to have hemolytic activity correlated. PLD has broad application prospects and reveals practical pharmacological activities in pre-clinical research. The authors believe that these activities of PLD contribute to the efficacy of PG. What is apparent is that the clinical translation of PLD still has a long way to go. With the help of modern technology, the scope of clinical applications of PLD is probable to be expanded from traditional applications to new fields.

Phytochemicals and mitochondria: Therapeutic allies against gastric cancer

BACKGROUND

Mitochondria are the energy factories of cells with the ability to modulate the cell cycle, cellular differentiation, signal transduction, growth, and apoptosis. Existing drugs targeting mitochondria in cancer treatment have disadvantages of drug resistance and side effects. Phytochemicals, which are widely found in plants, are bioactive compounds that could facilitate the development of new drugs for gastric cancer. Studies have shown that some phytochemicals can suppress the development of gastric cancer.

METHODS

We searched for data from PubMed, China National Knowledge Infrastructure, Web of Science, and Embase databases from initial establishment to December 2021 to review the mechanism by which phytochemicals suppress gastric cancer cell growth by modulating mitochondrial function. Phytochemicals were classified and summarized by their mechanisms of action.

RESULTS

Phytochemicals can interfere with mitochondria through several mechanisms to reach the goal of promoting apoptosis in gastric cancer cells. Some phytochemicals, e.g., daidzein and tetrandrine promoted cytochrome c spillover into the cytoplasm by modulating the members of the B-cell lymphoma-2 protein family and induced apoptotic body activity by activating the caspase protein family. Phytochemicals (e.g., celastrol and shikonin) could promote the accumulation of reactive oxygen species and reduce the mitochondrial membrane potential. Several phytochemicals (e.g., berberine and oleanolic acid) activated mitochondrial apoptotic submission via the phosphatidylinositol-3-kinase/Akt signaling pathway, thereby triggering apoptosis in gastric cancer cells. Several well-known phytochemicals that target mitochondria, including berberine, ginsenoside, and baicalein, showed the advantages of multiple targets, high efficacy, and fewer side effects.

CONCLUSIONS

Phytochemicals could target the mitochondria in the treatment of gastric cancer, providing potential directions and evidence for clinical translation. Drug discovery focused on phytochemicals has great potential to break barriers in cancer treatment.

Platycodin-D exerts its anti-cancer effect by promoting c-Myc protein ubiquitination and degradation in gastric cancer

Platycodin D (PD) is a triterpene saponin extracted from the root of Platycodon grandiflorum. It has been reported to exhibit multiple pharmacological and biological properties. There is substantial evidence to support that PD displays a wide range of anti-tumor activities. However, the detailed molecular mechanism still needs further elaboration. In the present study, to explore whether PD inhibits gastric cancer (GC) cell viability, eight GC cell lines and the GES-1 cell line (a gastric mucosal cell line) were tested. We found that PD exhibited better inhibitory activity on GC cell lines than on the non-tumor cell line. Besides, treatment with PD led to a significant cell cycle arrest, thereby causing subsequent apoptosis. Regarding the cell growth inhibition mechanism, PD can downregulate the protein level of c-Myc rather than its mRNA level in a dose-dependent manner. Further studies revealed that PD disturbed the overall ubiquitination level in GC cell lines and enhanced the ubiquitination-dependent degradation of c-Myc. Interestingly, the inhibition of cell viability by PD could be restored to a certain extent when the expression of c-Myc was recovered, suggesting that PD-mediated GC cell growth inhibition is closely associated with c-Myc expression. Our study proposes a novel molecular mechanism for PD inhibiting GC cell proliferation and growth by destabilizing the c-Myc protein. This work may lay a preliminary foundation for developing PD as an anti-cancer therapy.

Molecular mechanisms underlying the action of carcinogens in gastric cancer with a glimpse into targeted therapy

BACKGROUND

Gastric cancer imposes a substantial global health burden despite its overall incidence decrease. A broad spectrum of inherited, environmental and infectious factors contributes to the development of gastric cancer. A profound understanding of the molecular underpinnings of gastric cancer has lagged compared to several other tumors with similar incidence and morbidity rates, owing to our limited knowledge of the role of carcinogens in this malignancy. The International Agency for Research on Cancer (IARC) has classified gastric carcinogenic agents into four groups based on scientific evidence from human and experimental animal studies. This review aims to explore the potential comprehensive molecular and biological impacts of carcinogens on gastric cancer development and their interactions and interferences with various cellular signaling pathways.

CONCLUSIONS

In this review, we highlight recent clinical trial data reported in the literature dealing with different ways to target various carcinogens in gastric cancer. Moreover, we touch upon other multidisciplinary therapeutic approaches such as surgery, adjuvant and neoadjuvant chemotherapy. Rational clinical trials focusing on identifying suitable patient populations are imperative to the success of single-agent therapeutics. Novel insights regarding signaling pathways that regulate gastric cancer can potentially improve treatment responses to targeted therapy alone or in combination with other/conventional treatments. Preventive strategies such as control of H. pylori infection through eradication or immunization as well as dietary habit and lifestyle changes may reduce the incidence of this multifactorial disease, especially in high prevalence areas. Further in-depth understanding of the molecular mechanisms involved in the role of carcinogenic agents in gastric cancer development may offer valuable information and update state-of-the-art resources for physicians and researchers to explore novel ways to combat this disease, from bench to bedside. A schematic outlining of the interaction between gastric carcinogenic agents and intracellular pathways in gastric cancer H. pylori stimulates multiple intracellular pathways, including PI3K/AKT, NF-κB, Wnt, Shh, Ras/Raf, c-MET, and JAK/STAT, leading to epithelial cell proliferation and differentiation, apoptosis, survival, motility, and inflammatory cytokine release. EBV can stimulate intracellular pathways such as the PI3K/Akt, RAS/RAF, JAK/STAT, Notch, TGF-β, and NF-κB, leading to cell survival and motility, proliferation, invasion, metastasis, and the transcription of anti-apoptotic genes and pro-inflammatory cytokines. Nicotine and alcohol can lead to angiogenesis, metastasis, survival, proliferation, pro-inflammatory, migration, and chemotactic by stimulating various intracellular signaling pathways such as PI3K/AKT, NF-κB, Ras/Raf, ROS, and JAK/STAT. Processed meat contains numerous carcinogenic compounds that affect multiple intracellular pathways such as sGC/cGMP, p38 MAPK, ERK, and PI3K/AKT, leading to anti-apoptosis, angiogenesis, metastasis, inflammatory responses, proliferation, and invasion. Lead compounds may interact with multiple signaling pathways such as PI3K/AKT, NF-κB, Ras/Raf, DNA methylation-dependent, and epigenetic-dependent, leading to tumorigenesis, carcinogenesis, malignancy, angiogenesis, DNA hypermethylation, cell survival, and cell proliferation. Stimulating signaling pathways such as PI3K/Akt, RAS/RAF, JAK/STAT, WNT, TGF-β, EGF, FGFR2, and E-cadherin through UV ionizing radiation leads to cell survival, proliferation, and immortalization in gastric cancer. The consequence of PI3K/AKT, NF-κB, Ras/Raf, ROS, JAK/STAT, and WNT signaling stimulation by the carcinogenic component of Pickled vegetables and salted fish is the Warburg effect, tumorigenesis, angiogenesis, proliferation, inflammatory response, and migration.

Platycodin D induces apoptosis through JNK1/AP-1/PUMA pathway in non-small cell lung cancer cells: A new mechanism for an old compound

Platycodin D, a triterpenoid monomer, has been shown to possess an anti-tumor effect on various types of cancer. Although Platycodin D has been reported to suppress tumorigenesis, the detailed underlying mechanism remains elusive. Platycodin D treatment significantly reduced the cell viability, decreased the number of colonies, impaired the mitochondrial function, and induced apoptosis in non-small cell lung cancer (NSCLC) cells. To understand the mechanism by which platycodin D induces apoptosis, the expression levels of apoptosis-related proteins were examined, and we found that the expression of PUMA (p53 upregulated modulator of apoptosis) was upregulated upon platycodin D treatment. Knockdown of PUMA resulted in attenuation of platycodin D-induced apoptosis, indicating that PUMA up-regulation is essential for platycodin D to induce apoptosis. The induction of PUMA expression by platycodin D treatment was through activation of AP-1 since mutation of AP-1 binding site in the PUMA promoter abolished the PUMA promoter activity. In addition, the chromatin immunoprecipitation further demonstrated that platycodin D promoted AP-1 binding to PUMA promoter. Moreover, knockdown of JNK1, but not JNK2, significantly abolished the phosphorylation of c-Jun at Ser63 (a component of AP-1), decreased the platycodin D-induced expression of PUMA and cleaved caspase 3, indicating that platycodin D inhibits JNK1/AP-1 signaling pathway. Furthermore, immunohistochemical staining studies showed that tumors from the mice treated with platycodin D activated JNK by translocation of JNK into nuclei, increased phosphorylation of JNK and c-Jun at Ser63 in nuclei, and boosted the PUMA expression. Taken together, our in vitro and in vivo data revealed a novel mechanism by which platycodin D up-regulates PUMA to induce apoptosis through JNK1/AP-1 axis in NSCLC.

Platycodin D sensitizes KRAS-mutant colorectal cancer cells to cetuximab by inhibiting the PI3K/Akt signaling pathway

Cetuximab is a monoclonal antibody against epidermal growth factor receptor that blocks downstream signaling pathways of receptor tyrosine kinases, including Ras/Raf/MAPK and PI3K/Akt, thereby inhibiting tumor cell proliferation and inducing cancer cell apoptosis. Owing to KRAS mutations, the effectiveness of cetuximab is usually limited by intrinsic drug resistance. Continuous activation of the PI3K/Akt signaling pathway is another reason for cetuximab resistance. Platycodin-D, a bioactive compound isolated from the Chinese herb Platycodon grandiflorum, regulates Akt in different trends based on tissue types. To investigate whether platycodin-D can sensitize KRAS-mutant colorectal cancer cells to cetuximab by inhibiting the PI3K/Akt signaling pathway, HCT116 and LoVo cells were treated with cetuximab and platycodin-D. LY294002 and SC79 were used to regulate Akt to further evaluate whether platycodin-D sensitizes cells to cetuximab by inhibiting Akt. Our results confirmed that platycodin-D increased the cytotoxic effects of cetuximab, including inhibition of growth, migration, and invasion, via downregulation of PI3K and Akt phosphorylation in HCT116 and LoVo cells both in vitro and in vivo. Given these data, platycodin-D may sensitize KRAS-mutant colorectal cancer cells to cetuximab via inhibition of the PI3K/Akt signaling pathway.

Protective Effects of Platycodin D3 on Airway Remodeling and Inflammation via Modulating MAPK/NF-κB Signaling Pathway in Asthma Mice

Background

Asthma is a disease with airway hyperresponsive and airway inflammation. Platycodin D is a triterpenoid saponin extracted from Platycodon grandiflorus root, which has various pharmacological activities. The study mainly explored the effects of platycodin D3 (PD₃) in airway remodeling and inflammation of asthma.

Methods

The ovalbumin (OVA)-induced asthma mice were given PD3 (20 mg/kg, 40 mg/kg, and 80 mg/kg) in different groups. The asthma mice administrated with dexamethasone (DXM) were enrolled as the positive control group, and the normal control mice and asthma model mice separately received the same volume of saline. Mouse airway lung dynamic compliance (Cdyn) and total airway resistance (RL) were measured by the EMKA animal lung function analysis system. The inflammation factor levels were estimated by ELISA. Histopathological changes were tested by HE and PAS staining. The protein and phosphorylation levels of NF-κBp65, p38, ERK1/2, and JNK1/2 were detected by Western blot.

Results

In asthmatic mice, PD3 enhanced the airway Cdyn and decreased RL to improve the airway hyperreactivity and alleviated the pathological injury of lung tissues. In addition, PD3 could reduce the infiltration of inflammatory cells in BALF and suppress the levels of eotaxin, IL-4, IL-5, IL-13, IFN-γ, and IgE. Furthermore, PD3 treatment inhibited the phosphorylation of NF-κBp65, p38, ERK1/2, and JNK1/2 proteins in asthma mice.

Conclusion

PD3 treatment alleviated the airway remodeling and inflammation in asthmatic mice, which might be related to downregulating the phosphorylated proteins in the MAPK/NF-κB signaling pathway.

Platycodon grandiflorum Triggers Antitumor Immunity by Restricting PD-1 Expression of CD8+ T Cells in Local Tumor Microenvironment

In the tumor microenvironment (TME), the activation of programmed death-1 (PD-1)–programmed death ligand-1 (PD-L1) pathway is one of the main signals of immune escape and tumor deterioration. Clinically, the application of monoclonal antibodies slows down the progression of various malignancies and prolongs the survival of patients effectively. However, these treatments result in serious immune-related adverse events (irAEs) owning to systemic immune activation. Therefore, to achieve long-term therapeutic effects and low side effects, it is necessary to find drugs inhibiting the local PD-1/PD-L1 signaling pathway of the TME. Here, we discovered that Platycodon grandiflorum (PG), a medicine and food homology herb, reduced the expression of PD-1 on the surface of CD8⁺ T cells to exert antitumor effects in non-small cell lung cancer (NSCLC). Firstly, by combining systems pharmacology strategies and clinical data analysis, we found that PG has the potential to immunomodulate T cells and suppress tumors. Secondly, in vivo and in vitro experiments have confirmed the antitumor effect of the combination of Platycodin D and Platycodin D3, which is preferred and representative of the compounds. Mechanistically, PG increased the infiltration and killing activity of CD8⁺ T cells, which was related to the decrease of PD-1⁺ CD8⁺ T cells. Furthermore, we confirmed that PG regulated the expression of PD-1 on the surface of CD8⁺ T cells via reducing the secretion of VEGF-A regulated by the level of P-STAT3 in tumor cells. Additionally, PG also positively impacted the biological processes downstream of STAT3. Overall, we demonstrated that PG-mediated downregulation of PD-1 on the surface of CD8⁺ T cells represents a promising strategy to locally enhance T-cell responses and improve antitumor immunity.

Comprehensive review on signaling pathways of dietary saponins in cancer cells suppression

Nutrigenomics utilizes high-throughput genomic technologies to reveal changes in gene and protein levels. Excitingly, ever-growing body of scientific findings has provided sufficient evidence about the interplay between diet and genes. Cutting-edge research and advancements in genomics, epigenetics and metabolomics have deepened our understanding on the role of dietary factors in the inhibition of carcinogenesis and metastasis. Dietary saponins, a type of triterpene glycosides, are generally found in Platycodon grandifloras, Dioscorea oppositifolia, asparagus, legumes, and sea cucumber. Wealth of information has started to shed light on pleiotropic mechanistic roles of dietary saponins in cancer prevention and inhibition. In this review, we have attempted to summarize the in vitro research of dietary saponins in the last two decades by searching common databases such as Google Scholar, PubMed, Scopus, and Web of Science. The results showed that dietary saponins exerted anti-cancer activities via regulation of apoptosis, autophagy, arrest cell cycle, anti-proliferation, anti-metastasis, and anti-angiogenesis, by regulation of several critical signaling pathways, including MAPK, PI3K/Akt/mTOR, NF-κB, and VEGF/VEGFR. However, there is no data about the dosage of dietary saponins for practical anti-cancer effects in human bodies. Extensive clinical studies are needed to confirm the effectiveness of dietary saponins for further commercial and medical applications.

Terpenoids' anti-cancer effects: focus on autophagy

Terpenoids are the largest class of natural products, most of which are derived from plants. Amongst their numerous biological properties, their anti-tumor effects are of interest for they are extremely diverse which include anti-proliferative, apoptotic, anti-angiogenic, and anti-metastatic activities. Recently, several in vitro and in vivo studies have been dedicated to understanding the 'terpenoid induced autophagy' phenomenon in cancer cells. Light has already been shed on the intricacy of apoptosis and autophagy relationship. This latter crosstalk is driven by the delicate balance between activating or silencing of certain proteins whereby the outcome is expressed via interrelated signaling pathways. In this review, we focus on nine of the most studied terpenoids and on their cell death and autophagic activity. These terpenoids are grouped in three classes: sesquiterpenoid (artemisinin, parthenolide), diterpenoids (oridonin, triptolide), and triterpenoids (alisol, betulinic acid, oleanolic acid, platycodin D, and ursolic acid). We have selected these nine terpenoids among others as they belong to the different major classes of terpenoids and our extensive search of the literature indicated that they were the most studied in terms of autophagy in cancer. These terpenoids alone demonstrate the complexity by which these secondary metabolites induce autophagy via complex signaling pathways such as MAPK/ERK/JNK, PI3K/AKT/mTOR, AMPK, NF-kB, and reactive oxygen species. Moreover, induction of autophagy can be either destructive or protective in tumor cells. Nevertheless, should this phenomenon be well understood, we ought to be able to exploit it to create novel therapies and design more effective regimens in the management and treatment of cancer.

Platycodin D attenuates airway inflammation via suppression Th2 transcription factor in a murine model of acute asthma

Introduction: Bronchial asthma is a common chronic inflammatory condition of the airway tissue. Platycodin D (PLD) has antiinflammatory effects in a mouse model of allergic asthma. In this work, the anti-asthma potential of PLD was studied by investigation of its effect to suppress airway inflammation and mucin production, a murine model of asthma and the possible mechanisms.Methods: Mice were randomly assigned to five experimental groups: control, ovalbumin (OVA), OVA+ICS (intranasal fluticasone), OVA+PLD and OVA+PLD/ICS. Airway histological studies were evaluated by the H&E staining; IL-4, IL-5, and IL-13 in bronchoalveolar lavage fluid were evaluated by ELISA; GATA3 and IRF4 mRNA of airway were measured by RT-PCR and their protein level were measured by Western blotting.Results: Our study showed that PLD suppressed eosinophilic inflammation and mucin production in bronchial mucosa. Moreover, PLD inhibited production of Th2 cytokines such as IL-4, IL-5, and IL-13. Protein production of GATA3 and IRF4, were also decreased in PLD treated OVA asthma model. Taken together, our results provided evidence that PLD inhibits the airway inflammation via suppression of Th2 transcription factor production.Conclusion: These findings suggest that PLD may effectively ameliorate the progression of asthma. These results suggest that PLD could be used as a therapy for allergic asthma.

Anti-obesity Medications in Cancer Therapy: A Comprehensive Insight

The interplay between cancer and obesity is multifactorial and complex with the increased risk of cancer development in obese individuals posing a significant threat. Obesity leads to the upregulation or hyperactivation of several oncogenic pathways in cancer cells, which drives them towards a deleterious phenotype. The cross-talk between cancer and obesity is considered a large contributing factor in the development of chemotherapeutic drug resistance and the resistance to radiotherapy. The link between obesity and the development of cancer is so strong that a medication that demonstrates effectiveness against both conditions would serve as an essential step. In this context, anti-obesity medications provide a worthy list of candidates based on their chemo-preventive potential and chemotherapeutic properties. The current study focuses on exploring the potential of anti-obesity medicines as dual anticancer drugs. These medications target several key signaling pathways (e.g., AMPK, PI3K/Akt/mTOR, MAPK, NF-κB, JNK/ERK), which prove to be crucial for both cancer growth and metastases. Some of these drugs also play an important role in attenuating the signaling and cellular events which incite cancer-obesity cross-talk and demonstrate efficient counteraction of neoplastic transformation. Thus, this review highlights a comprehensive view of the potential use of anti-obesity medicines to treat both cancer and obesity for patients exhibiting both comorbities.

New bioactive 5-arylcarboximidamidopyrazolo[3,4-c]pyridines: Synthesis, cytotoxic activity, mechanistic investigation and structure-activity relationships

In this study, a series of novel substituted pyrazolo[3,4-c]pyridin-5-ylamidines was synthesized and their cytotoxicity against three cancer cell lines (MDA-MB-231, HT-1080, PC-3), as well as a human normal cell line (AG01523) was evaluated. A number of derivatives could strongly reduce cancer cells proliferation and exhibit apoptotic induction capability, while reasonable structure-activity relationships could be extracted. Certain analogues were endowed with low toxicity against normal cells. Cell cycle analysis revealed that most of the active compounds induced a G₀/G₁ arrest of HT-1080 cells. Moreover, the potential mechanisms of the cytotoxic activity of the promising compounds were investigated in HT-1080 cells, upon study of their effects on the phosphorylation of Akt, ERK and p38 MAPK. Most of the active derivatives inhibit phosphorylation of Akt and ERK and/or induce p38 MAPK phosphorylation, providing a potential indication on the mode of action of this class.

Platycodin D reverses histone deacetylase inhibitor resistance in hepatocellular carcinoma cells by repressing ERK1/2-mediated cofilin-1 phosphorylation

BACKGROUND

Chemoresistance remains the main obstacle in hepatocellular carcinoma (HCC) therapy. Despite significant advances in HCC therapy, HCC still has a poor prognosis. Thus, there is an urgent need to identify a treatment target to reverse HCC chemotherapy resistance. Platycodon grandiflorus (PG) is a perennial herb that has been used as food and traditional Chinese medicine for thousands of years in Northeast Asia. Platycodin D (PD), a main active triterpenoid saponin found in the root of PG, has been reported to possess anticancer properties in several cancer cell lines, including HCC; however, the reversal effect of this molecule on HCC chemoresistance remains largely unknown.

PURPOSE

This study aimed to investigate the role and the mechanism of PD-mediated reversal of the histone deacetylase inhibitor (HDACi) resistance in HCC cells.

METHODS

Human HCC cells (HA22T) and HDACi-resistant (HDACi-R) cells were used. Cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Combination index was used to calculate the synergism potential. Expression of ERK1/2 (total/phospho), cofilin-1 (total/phospho) and apoptosis-related protein was determined using western blotting. Mitochondrial membrane potential was assessed using the JC-1 (5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanine iodide) probe. Apoptosis was detected using the terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Mitochondrial reactive oxygen species generation was measured using the MitoSOX Red fluorescent probe.

RESULTS

We found that PD treatment inhibited cell viability both in HA22T HCC and HDACi-R cells. Inhibition of ERK1/2 by PD98059 could reverse drug resistance in HDACi-R cells treated with PD98059 and PD. Nevertheless, pre-treatment with U46619, an ERK1/2 activator, rescued PD-induced apoptosis by decreasing levels of apoptosis-related proteins in HCC cells. The combined treatment of PD with apicidin a powerful HDACi, dramatically enhanced the apoptotic effect in HDACi-R cells.

CONCLUSION

For the first time, we showed that PD reversed HDACi resistance in HCC by repressing ERK1/2-mediated cofilin-1 phosphorylation. Thus, PD can potentially be a treatment target to reverse HCC chemotherapy resistance in future therapeutic trials.

Effects of Platycodin D on apoptosis, migration, invasion and cell cycle arrest of gallbladder cancer cells

Platycodin D (PD) is a triterpenoid saponin that exists in the roots of Platycodonis. It exhibits evident growth inhibitory effects and potent cytotoxicity against multiple types of cancer. Gallbladder cancer (GBC) is the most common malignant disease of the biliary tract system. Patients with GBC usually have limited available treatment strategies and a poor prognosis. The present study investigated the antitumor effects of PD on human GBC cells in vitro and its underlying molecular mechanisms of action. The results indicated that PD, as assessed using MTT and colony forming assays, induced evident growth inhibition. Flow cytometry indicated that PD robustly induced apoptosis and blocked GBC cells at the G₂/M phase. Cell migration and invasion assays demonstrated that PD effectively inhibited the migratory and invasive abilities of GBC cell lines. Western blotting indicated that PD may initiate mitochondrial destruction in GBC cells through the JNK signaling pathway, thereby inducing apoptosis. The present results indicated that PD may exhibit antitumor effects by inducing apoptosis; inhibiting migration and invasion; and affecting the cell cycle in GBC cells. Therefore, PD has the potential to become a novel antitumor drug for GBC therapy.

Platycodin D suppresses cisplatin-induced cytotoxicity by suppressing ROS-mediated oxidative damage, apoptosis, and inflammation in HEK-293 cells

Cisplatin, a proven effective chemotherapeutic agent, has been used clinically to treat malignant solid tumors, whereas its clinical use is limited by serious side effect including nephrotoxicity. Platycodin D (PD), the major and marked saponin isolated from Platycodon grandiflorum, possesses many pharmacological effects. In this study, we evaluated its protective effect against cisplatin-induced human embryonic kidney 293 (HEK-293) cells injury and elucidated the related mechanisms. Our results showed that PD (0.25, 0.5, and 1 μM) can dose-dependently alleviate oxidative stress by decreasing malondialdehyde and reactive oxygen species, while increasing the levels of glutathione, superoxide dismutase, and catalase. Moreover, the elevation of apoptosis including Bax, Bad, cleaved caspase-3,-9, and decreased protein levels of Bcl-2, Bcl-XL induced by cisplatin were reversed after PD treatment. Importantly, PD pretreatment can also regulate PI3K/Akt and ERK/JNK/p38 signaling pathways. Furthermore, PD was found to reduce NF-κB-mediated inflammatory relative proteins. Our finding indicated that PD exerted significant effects on cisplatin induced oxidative stress, apoptosis and inflammatory, which will provide evidence for the development of PD to attenuate cisplatin-induced nephrotoxicity.

Biotransformation of Glycosylated Saponins in Balloon Flower Root Extract into 3-O-β-D-Glucopyranosyl Platycosides by Deglycosylation of Pectinase from Aspergillus aculeatus

Platycodon grandiflorum root (Platycodi radix) saponins, platycosides, have been used as health supplements and food items for the treatment of respiratory disorders and pulmonary diseases. Deglycosylated saponins have been known to exert stronger biological effects than their glycosylated forms. In the present study, glycosylated platycosides in Platycodi radix extract were biotransformed into deglycosylated 3-O-β-D-glucopyranosyl platycosides, including 3-O-β-Dglucopyranosyl platycodigenin, 3-O-β-D-glucopyranosyl polygalacic acid, and 3-O-β-Dglucopyranosyl platyconic acid, by pectinase from Aspergillus aculeatus. This is the first report on the quantitative enzymatic production of 3-O-β-D-glucopyranosyl platycosides. The chemical structures of 3-O-β-D-glucopyranosyl platycosides were identified with LC/MS. Moreover, the biotransformation pathways of the three types of platycosides in Platycodi radix into 3-O-β-Dglucopyranosyl platycosides were established.

Bioactive platycodins from Platycodonis Radix: Phytochemistry, pharmacological activities, toxicology and pharmacokinetics

Platycodonis Radix, the root of Platycodon grandiflorum (Jacq.) A. DC., is a well-known edible herbal medicine. It is a common vegetable used for the preparation of side dish, kimchi, dessert, and tea. Besides, it has been used to treat respiratory disease including cough, excessive phlegm, and sore throat for a long history. In the past decades, the bioactive components and the pharmacological activities of Platycodonis Radix have been widely investigated. Thereinto, platycodins, the oleanane-type triterpenoid saponins were demonstrated to be the main bioactive components in Platycodonis Radix, and more than 70 platycodins have been identified up to date. This paper mainly reviewed the phytochemistry, pharmacological activities (apophlegmatic, anti-tussive, anti-inflammatory, anti-cancer, anti-obesity, anti-diabetic, immunomodulatory, cardiovascular protective, and hepatoprotective activities, etc.), toxicology and pharmacokinetics of platycodins isolated from Platycodonis Radix, aiming to promote further investigation on therapeutic potential of these platycodins.

Anticancer Potential of Raddeanin A, a Natural Triterpenoid Isolated from Anemone raddeana Regel

Natural compounds extracted from plants have gained immense importance in the fight against cancer cells due to their lesser toxicity and potential therapeutic effects. Raddeanin A (RA), an oleanane type triterpenoid is a major compound isolated from Anemone raddeana Regel. As an anticancer agent, RA induces apoptosis, cell cycle arrest, inhibits invasion, migration and angiogenesis in malignant cell lines as well as in preclinical models. In this systemic review, the pharmacological effects of RA and its underlying molecular mechanisms were carefully analyzed and potential molecular targets have been highlighted. The apoptotic potential of RA can be mediated through the modulation of Bcl-2, Bax, caspase-3, caspase-8, caspase-9, cytochrome c and poly-ADP ribose polymerase (PARP) cleavage. PI3K/Akt signaling pathway serves as the major molecular target affected by RA. Furthermore, RA can block cell proliferation through inhibition of canonical Wnt/β-catenin signaling pathway in colorectal cancer cells. RA can also alter the activation of NF-κB and STAT3 signaling pathways to suppress invasion and metastasis. RA has also exhibited promising anticancer potential against drug resistant cancer cells and can enhance the anticancer effects of several chemotherapeutic agents. Overall, RA may function as a promising compound in combating cancer, although further in-depth study is required under clinical settings to validate its efficacy in cancer patients.

Some Ototoxic Drugs Destroy Cochlear Support Cells Before Damaging Sensory Hair Cells

A wide variety of ototoxic drugs are capable of damaging the sensory hair cells in the mammalian cochlea resulting in permanent hearing loss. However, the toxic properties of these drugs suggest that some could potentially damage cochlear support cells as well. To test the hypothesis, we treated postnatal day three rat cochlear cultures with toxic doses of gentamicin, cisplatin, mefloquine, and cadmium. Gentamicin primarily destroyed the hair cells and disrupted the intercellular connection with the surrounding support cells. Gentamicin-induced hair cell death was initiated through the caspase-9 intrinsic apoptotic pathway followed by activation of downstream executioner caspase-3. In contrast, cisplatin, mefloquine, and cadmium initially damaged the support cells and only later damaged the hair cells. Support cell death was initiated through the caspase-8 extrinsic apoptotic pathway followed later by downstream activation of caspase-3. Cisplatin, mefloquine, and cadmium significantly reduced the expression of actin and laminin, in the extracellular matrix, leading to significant disarray of the sensory epithelium.

Immuno-enhancement effects of Platycodon grandiflorum extracts in splenocytes and a cyclophosphamide-induced immunosuppressed rat model

Background

Platycodon grandiflorum is a flowering plant that is used in traditional medicine for treating pulmonary and respiratory disorders. It exerts various pharmacological effects, including immunomodulatory and anti-cancer activities. The purpose of this study was to confirm the in vitro and in vivo immune-enhancing effects of P. grandiflorum extract (PGE) on splenocytes isolated from cyclophosphamide (CP)-induced immunosuppressed rats.

Methods

For in vitro analysis, splenocytes were treated with PGE at various doses along with CP. Cell viability was measured by a WST-1 assay, and NK cell activity and cytotoxic T lymphocyte (CTL) activity was also examined. In addition, immunoglobulin A (IgA), IgG, and cytokine levels were measured. For in vivo analysis, Sprague Dawley rats were treated with various doses of PGE along with CP. Complete blood count (CBC) was performed, and plasma levels of IgA, IgG, TNF-α, IFN-γ, IL-2, and IL-12 were quantified. Additionally, tissue damage was assessed through histological analyses of the thymus and spleen.

Results

PGE treatment enhanced cell viability and natural killer cell and cytotoxic T lymphocyte activity, and increased the production of CP-induced inflammatory cytokines (TNF-α, IFN-γ, IL-2, and IL-12) and immunoglobulins (IgG and IgA) in splenocytes. In addition, in CP-treated rats, PGE treatment induced the recovery of white blood cell, neutrophil, and lymphocyte counts, along with mid-range absolute counts, and increased the serum levels of inflammatory cytokines (TNF-α, IFN-γ, IL-2, and IL-12) and immunoglobulins (IgG and IgA). Moreover, PGE attenuated CP-induced spleen and thymic damage.

Conclusions

Our results confirmed that PGE exerts an immune-enhancing effect both in vitro and in vivo, suggesting that PGE may have applications as a component of immunostimulatory agents or as an ingredient in functional foods.

miR-34a Enhances the Susceptibility of Gastric Cancer to Platycodin D by Targeting Survivin

INTRODUCTION

Platycodin D (PD), a triterpenoid saponin isolated from Platycodon grandiflorum, has a well-known anti-tumor effect in multiple human cancers, including gastric cancer (GC). miR-34a plays an important role in the progression of GC. However, the relationship between miR-34a and the susceptibility of GC cells to PD is still unclear. The aim of our research was to investigate the functions of miR-34a in mediating the susceptibility of GC to PD.

METHODS

qPCR was performed to detect the expression level of miR-34a and survivin in GC cells. The expression of survivin, Bcl-2, Bax, and cleaved caspase-3 was analyzed using Western blot. Cell viability was detected by MTT assay, and apoptosis was analyzed via Annexin V-FITC/PI staining followed by flow cy-tometry. The colony formation and scratch-wound assays were applied to assess cell proliferation and migration. Caspase-3/7 activity was detected by a Caspase-Glo®3/7 detection kit. The relationship between miR-34a and survivin was determined by dual luciferase reporter gene assay. Finally, a GC xenograft mouse model was used to confirm our findings in vivo.

RESULTS

The expression of miR-34a decreased but survivin increased inversely in human GC cells. Survivin is a direct target of miR-34a and may be negatively regulated by miR-34a. PD could inhibit GC cell proliferation and induce apoptosis. Importantly, overexpression miR-34a or suppressing survivin was shown to enhance the susceptibility of GC to PD both in vitro and in vivo.

CONCLUSIONS

miR-34a could modulate the susceptibility of GC to PD via targeting survivin, suggesting miR-34a overexpression may serve as a novel strategy to sensitize GC to anti-cancer drugs.

Glycitein induces reactive oxygen species-dependent apoptosis and G0/G1 cell cycle arrest through the MAPK/STAT3/NF-κB pathway in human gastric cancer cells

Glycitein is an isoflavone that reportedly inhibits the proliferation of human breast cancer and prostate cancer cells. However, its anti-cancer molecular mechanisms in human gastric cancer remain to be defined. This study evaluated the antitumor effects of glycitein on human gastric cancer cells and investigated the underlying mechanisms. We used MTT assay, flow cytometry and western blotting to investigate its molecular mechanisms with focus on reactive oxygen species (ROS) production. Our results showed that glycitein had significant cytotoxic effects on human gastric cancer cells. Glycitein markedly decreased mitochondrial transmembrane potential (ΔΨm) and increased AGS cells mitochondrial-related apoptosis, and caused G0/G1 cell cycle arrest by regulating cycle-related protein. Mechanistically, accompanying ROS, glycitein can activate mitogen-activated protein kinase (MAPK) and inhibited the signal transducer and activator of transcription 3 (STAT3) and nuclear factor-kappaB (NF-κB) signaling pathways. Furthermore, the MAPK signaling pathway regulated the expression levels of STAT3 and NF-κB upon treatment with MAPK inhibitor and N-acetyl-L-cysteine (NAC). These findings suggested that glycitein induced AGS cell apoptosis and G0/G1 phase cell cycle arrest via ROS-related MAPK/STAT3/NF-κB signaling pathways. Thus, glycitein has the potential to a novel targeted therapeutic agent for human gastric cancer.

Biocatalysis of Platycoside E and Platycodin D3 Using Fungal Extracellular β-Glucosidase Responsible for Rapid Platycodin D Production

Platycodi radix (i.e., Platycodon grandiflorum root) products (e.g., tea, cosmetics, and herbal supplements) are popular in East Asian nutraceutical markets due to their reported health benefits and positive consumer perceptions. Platycosides are the key drivers of Platycodi radixes' biofunctional effects; their nutraceutical and pharmaceutical activities are primarily related to the number and varieties of sugar side-chains. Among the various platycosides, platycodin D is a major saponin that demonstrates various nutraceutical activities. Therefore, the development of a novel technology to increase the total platycodin D content in Platycodi radix extract is important, not only for consumers' health benefits but also producers' commercial applications and manufacturing cost reduction. It has been reported that hydrolysis of platycoside sugar moieties significantly modifies the compound's biofunctionality. Platycodi radix extract naturally contains two major platycodin D precursors (platycoside E and platycodin D3) which can be enzymatically converted to platycodin D via β-d-glucosidase hydrolysis. Despite evidence that platycodin D precursors can be changed to platycodin D in the Platycodi radix plant, there is little research on increasing platycodin D concentrations during processing. In this work, platycodin D levels in Platycodi radix extracts were significantly increased via extracellular Aspergillus usamii β-d-glucosidase (n = 3, p < 0.001). To increase the extracellular β-d-glucosidase activity, A. usamii was cultivated in a culture media containing cellobiose as its major carbon source. The optimal pH and temperature of the fungal β-d-glucosidase were 6.0 and 40.0 °C, respectively. Extracellular A. usamii β-d-glucosidase successfully converted more than 99.9% (w/v, n = 3, p < 0.001) of platycoside E and platycodin D3 into platycodin D within 2 h under optimal conditions. The maximum level of platycodin D was 0.4 mM. Following the biotransformation process, the platycodin D was recovered using preparatory High Performance Liquid Chromatography (HPLC) and applied to in vitro assays to evaluate its quality. Platycodin D separated from the Platycodi radix immediately following the bioconversion process showed significant anti-inflammatory effects from the Lipopolysaccharide (LPS)-induced macrophage inflammatory responses with decreased nitrite and IL-6 production (n = 3, p < 0.001). Taken together, these results provide evidence that biocatalysis of Platycodi radix extracts with A. usamii may be used as an efficient method of platycodin D-enriched extract production and novel Platycodi radix products may thereby be created.

Inhibition of miR-126 protects chondrocytes from IL-1β induced inflammation via upregulation of Bcl-2

OBJECTIVES

The aim of this study was to investigate the role of miR-126 in the development of osteoarthritis, as well as the potential molecular mechanisms involved, in order to provide a theoretical basis for osteoarthritis treatment and a novel perspective for clinical therapy.

METHODS

Human chondrocyte cell line CHON-001 was administrated by different doses of interleukin (IL)-1β to simulate inflammation. Cell viability, migration, apoptosis, IL-6, IL-8, and tumour necrosis factor (TNF)-α expression, as well as expression of apoptosis-related factors, were measured to assess inflammation. miR-126 expression was measured by quantitative polymerase chain reaction (qPCR). Cells were then transfected with miR-126 inhibitor to assess the effect of miR-126 on IL-1β-injured CHON-001 cells. Expression of B-cell lymphoma 2 (Bcl-2) and the activity of mitogen-activated protein kinase (MAPK) / Jun N-terminal kinase (JNK) signaling pathway were measured by Western blot to explore the underlying mechanism through which miR-126 affects IL-1β-induced inflammation.

RESULTS

After IL-1β administration, cell viability and migration were suppressed while apoptosis was enhanced. Expression of IL-6, IL-8, and TNF-α were all increased, and miR-126 was upregulated. In IL-1β-administrated CHON-001 cells, miR-126 inhibitor suppressed the effect of IL-1β on cell viability, migration, apoptosis, and inflammatory response. Bcl-2 expression was negatively regulated with miR-126 in IL-1β-administrated cells, and thus affected expressions of phosphorylated MAPK and JNK.

CONCLUSION

IL-1β-induced inflammatory markers and miR-126 was upregulated. Inhibition of miR-126 decreased IL-1β-induced inflammation and cell apoptosis, and upregulated Bcl-2 expression via inactivating the MAKP/JNK signalling pathway.Cite this article: C. D. Yu, W. H. Miao, Y. Y. Zhang, M. J. Zou, X. F. Yan. Inhibition of miR-126 protects chondrocytes from IL-1β induced inflammation via upregulation of Bcl-2. Bone Joint Res 2018;7:414-421. DOI: 10.1302/2046-3758.76.BJR-2017-0138.R1.

Anti-tumour effects of beta-sitosterol are mediated by AMPK/PTEN/HSP90 axis in AGS human gastric adenocarcinoma cells and xenograft mouse models

We investigated the anti-cancer effects of beta-sitosterol (BS), a plant-derived sterol in AGS human gastric adenocarcinoma cells and xenograft mouse models. BS significantly reduced cell viability by inducing apoptosis in AGS adenocarcinoma cells. This was accompanied by the formation of apoptotic bodies, as detected by Annexin V, caspase 3/7 activity, and MitoPotential assay. BS stimulated phosphatase and tensin homolog (PTEN) and phospho-AMP-activated protein kinase (p-AMPK) expression. Pharmacological inhibitors or siRNA were used to further analyse the relationship between the two proteins. AMPK was found to represent a likely upstream regulator of PTEN. Additionally, two-dimensional gel electrophoresis was used to identify related proteins in the treatment of BS. The decrease of Hsp90 protein by BS was observed. Induction of PTEN protein and reduction of Hsp90 was mediated by AICAR, an AMPK activator, indicating that AMPK is necessary for PTEN and Hsp90 expression. Additionally, BS was found to be effective through the regulation of cancer biomarker. Furthermore, BS suppressed tumour growth without toxicity in the AGS xenograft mouse models-. Taken together, the present results demonstrate that BS exerts anti-cancer effects in AGS cells and xenograft mouse models by mediating AMPK, PTEN, and Hsp90.

Deconvoluting the relationships between autophagy and metastasis for potential cancer therapy

Autophagy is a highly conserved lysosome-dependent degradation process that may digest some long-lived proteins and damaged organelles. As an essential homeostasis maintaining system in normal cells, autophagy plays a key role in several pathological settings, especially cancer. Metastasis, known as a crucial hallmark of cancer progression, is the primary cause of cancer lethality. The role of autophagy in metastasis is quite complex as supportive evidence has indicated both pro-metastatic and anti-metastatic functions of autophagy. Autophagy can inhibit metastasis by restricting necrosis and mediating autophagic cell death, whereas it may also promote metastasis by enhancing cancer cell fitness in response to stress. Moreover, the function of autophagy is context- and stage-dependent. Specifically, during the early steps of metastasis, autophagy mainly serves as a suppressor, while it plays a pro-metastatic role in the later steps. Here, we focus on highlighting the dual roles of autophagy in metastasis and address the molecular mechanisms involved in this process, which may provide a new insight into cancer biology. While, we also summarize several anti-metastatic agents manipulating autophagy, in the hope of shedding light on exploration of potential novel drugs for future cancer therapy.

Platycodin D Inhibits Inflammatory Response in LPS-Stimulated Primary Rat Microglia Cells through Activating LXRα-ABCA1 Signaling Pathway

Platycodin D (PLD), an effective triterpenesaponin extracted from Platycodon grandiflorum, has been known to have anti-inflammatory effect. In the present study, we investigate the anti-inflammatory effects of PLD on LPS-induced inflammation in primary rat microglia cells. The results showed that PLD significantly inhibited LPS-induced ROS, TNF-α, IL-6, and IL-1β production in primary rat microglia cells. PLD also inhibited LPS-induced NF-κB activation. Furthermore, our results showed that PLD prevented LPS-induced TLR4 translocation into lipid rafts via disrupting the formation of lipid rafts by inducing cholesterol efflux. In addition, PLD could activate LXRα–ABCA1 signaling pathway which induces cholesterol efflux from cells. The inhibition of inflammatory cytokines by PLD could be reversed by SiRNA of LXRα. In conclusion, these results indicated that PLD prevented LPS-induced inflammation by activating LXRα–ABCA1 signaling pathway, which disrupted lipid rafts and prevented TLR4 translocation into lipid rafts, thereby inhibiting LPS-induced inflammatory response.

Platycodin D, a triterpenoid saponin from Platycodon grandiflorum, suppresses the growth and invasion of human oral squamous cell carcinoma cells via the NF-κB pathway

This work was undertaken to explore the effects of platycodin D, a triterpenoid saponin from Platycodon grandiflorum, on the growth and invasiveness of human oral squamous cell carcinoma (OSCC). Platycodin D caused a significant, concentration-dependent inhibition of cell viability and induced significant apoptosis in OSCC cells. Moreover, platycodin D significantly inhibited OSCC cell invasion. At the molecular level, platycodin D increased the amounts of IκBα protein and reduced the expression of phosphorylated NF-κB p65, MMP-2, and MMP-9. Ectopic expression of constitutively active NF-κB p65 prevented platycodin D-mediated induction of apoptosis and suppression of invasion in OSCC cells. In vivo studies confirmed that platycodin D retarded the growth of subcutaneous SCC-4 xenograft tumors and reduced phosphorylation of NF-κB p65. Altogether, platycodin D shows inhibitory activity on OSCC growth and invasion through inactivation of the NF-κB pathway and might provide therapeutic benefits in the treatment of OSCC.

Silencing of FANCD2 enhances the radiosensitivity of metastatic cervical lymph node-derived head and neck squamous cell carcinoma HSC-4 cells

Fanconi anemia complementation group D2 (FANCD2) is involved in the key steps of the Fanconi anemia (FA) pathway, which plays a role in the repair of DNA crosslink damage. However, the role of FANCD2 during radiotherapy for head and neck squamous cell carcinoma (HNSCC) is unclear. In this study, the HNSCC cell line HSC-4 was used. Western blotting was used to evaluate the expression of the FANCD2 in HSC-4 cells. We investigated the impact of FANCD2 on the radiosensitivity of HSC-4 cells in vitro and in vivo. TUNEL, western blotting and immunohistochemistry were used to analyze the apoptosis and proteins involved in apoptosis-related pathways after radiotherapy to investigate the relevant mechanism. The present study showed that shRNA interference could effectively and stably silence FANCD2 expression in HSC-4 cells. In vitro, the silencing of FANCD2 inhibited cell proliferation, decreased the survival rate, increased apoptosis and induced S phase arrest in HSC-4 cells after radiotherapy. In vivo, the silencing of FANCD2 could prolong the tumor-forming time and slow tumor growth. In addition, the tumor volume was significantly reduced, the weight was deceased, and the tumor inhibition rate was increased after radiotherapy. TUNEL showed that the silencing of FANCD2 significantly increased apoptosis in HSC-4 cells induced by radiotherapy. Both in vitro and in vivo esperiments revealed that the expression of the Bax and p-p38 proteins in HSC-4 cells, in which FANCD2 had been silenced, was increased after radiotherapy, whereas the expression of the p38 and Bcl2 proteins was decreased. Our results suggested that the silencing of FANCD2 enhanced the radiosensitivity of HSC-4 cells, and its mechanism involves the activation of the p38 MAPK signaling pathway and the regulation of the expression of Bax and Bcl2 proteins. This study provides a novel candidate target for HNSCC therapy.

A platycoside-rich fraction from the root of Platycodon grandiflorum enhances cell death in A549 human lung carcinoma cells via mainly AMPK/mTOR/AKT signal-mediated autophagy induction

ETHNOPHARMACOLOGICAL RELEVANCE

The root of Platycodon grandiflorum (PG), commonly known as Kilkyong in Korea, Jiegeng in China, and Kikyo in Japan, has been extensively used as a traditional anti-inflammatory medicine in Asia for the treatment of respiratory conditions, such as bronchitis, asthma, and tonsillitis. Platycosides isolated from PG are especially well-known for their anti-cancer effects.

AIM OF THE STUDY

We investigated the involvement of autophagic cell death and other potential molecular mechanisms induced by the platycoside-containing butanol fraction of PG (PGB) in human lung carcinoma cells.

MATERIALS AND METHODS

PGB-induced growth inhibition and cell death were measured using a 5-diphenyl-tetrazolium bromide (MTT) assay. The effects of PGB on autophagy were determined by observing microtubule-associated protein 1 light chain 3 (LC3) redistribution with confocal microscopy. The PGB-mediated regulation of autophagy-associated proteins was investigated using Western blotting analysis. Furthermore, the anti-cancer mechanism of PGB was confirmed using chemical inhibitors. A high-performance liquid chromatography (HPLC)-DAD system was used to analyze the platycosides in PGB.

RESULTS

In A549 cells, PGB induced significant autophagic cell death. Specifically, PGB upregulated LC3-II in a time- and dose-dependent manner, and it redistributed LC3 via autophagosome formation in the cytoplasm. PGB treatment increased the phosphorylation of AMP-activated protein kinase (AMPK) and subsequently suppressed the AKT/mammalian target of the rapamycin (mTOR) pathway. Furthermore, PGB inhibited cell proliferation by regulating the mitogen-activated protein kinase (MAPK) pathways. In this study, six types of platycosides were identified in the PGB using HPLC.

CONCLUSIONS

PGB efficiently induced cancer cell death via autophagy and the modulation of the AMPK/mTOR/AKT and MAPK signaling pathways in A549 cells. Therefore, PGB may be an efficacious herbal anti-cancer therapy.

Dihydrotanshinone induces apoptosis of SGC7901 and MGC803 cells via activation of JNK and p38 signalling pathways

CONTEXT

Dihydrotanshinone (DHT), a natural compound from Salvia miltiorrhiza Bunge (Lamiaceae), showed higher cytotoxic potential compared with other tanshinones. Its effect and mechanism on gastric cancer have not been investigated.

OBJECTIVE

This study evaluates the effects of DHT on cell proliferation and apoptosis on gastric cancer cells, and elucidates its molecular mechanisms.

MATERIALS AND METHODS

Human gastric cancer MGC803 and SGC7901 cells were treated with various concentrations of DHT (0-15 μM) for 24 and 48 h, and cell growth was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. Cell apoptosis was analysed by flow cytometry and DAPI staining. Western blots were performed to investigate changes in the level of apoptosis related genes in gastric cancer cell.

RESULTS

DHT exhibited obvious inhibition of the survival of gastric cancer cells. The IC₅₀ values in SGC7901 and MGC803 cells were 9.14 and 5.39 μM for 24 h, respectively. Cells treated with 6 μM DHT resulted in 41.3% and 35.4% apoptotic cell fractions in SGC7901 and MGC803 cells, respectively, significantly higher than that of the control. Hallmarks of apoptosis were observed in gastric cancer cells after DHT exposure. DHT enhanced the expression levels of cleaved caspase-3, caspase-9 and poly-ADP-ribose polymerases. Furthermore, DHT increased the phosphorylation of JNK and p38 in SGC7901 and MGC803 cells.

CONCLUSION

DHT induced growth inhibition and apoptosis of gastric cancer cells, involving activation of caspase proteins and the JNK/p38 signaling pathway. The results indicated that DHT has a promising chemotherapeutic potential for human gastric cancer.

Autophagy Protects from Raddeanin A-Induced Apoptosis in SGC-7901 Human Gastric Cancer Cells

Raddeanin A (RA) is an extractive from Anemone raddeana Regel, a traditional Chinese medicine. The aim of this study is to assess the efficacy of RA against human gastric cancer (GC) cells (SGC-7901) and explore its mechanism. MTT assay showed that RA inhibition of proliferation of SGC-7901 cells increased in a dose-dependent manner. Flow cytometry analysis and Hoechst 33258 staining showed that RA induced apoptosis on SGC-7901 cells. Meanwhile, it induced autophagy. Western blotting analysis showed that the RA induces apoptosis and autophagy by activating p38 MAPK pathway and inhibiting mTOR pathway. Further studies showed that autophagy inhibition could protect from RA-induced apoptosis in SGC-7901 cells. In conclusion, RA can induce SGC-7901 cell apoptosis and autophagy by activating p38 MAPK pathway. And autophagy can protect SGC-7901 cells from apoptosis induced by RA.

Platycodin D inhibits interleukin-13-induced the expression of inflammatory cytokines and mucus in nasal epithelial cells

Allergic rhinitis (AR) is a common chronic inflammatory condition of the nasal mucosal tissue. Platycodin D (PLD), a triterpenoid saponin isolated from the root of Platycodon grandiflorum, has anti-inflammatory effects in a mouse model of allergic asthma. However, the anti-inflammatory effects of PLD in the nasal mucosa have not been deeply investigated. The objective was to investigate the effect of PLD on inflammatory cytokines and mucus production from nasal epithelial cells. Our study showed that PLD inhibited the levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) and eotaxin in interleukin (IL)-13-stimulated RPMI2650 cells. PLD also suppressed IL-13-induced mucin 5AC (MUC5AC) expression in RPMI2650 cells. Moreover, PLD treatment prevented IL-13-induced p-NF-κB p65 expression in RPMI2650 cells, as well as MAPK signaling pathway activation. Taken together, our results provided evidence that PLD inhibits IL-13-induced the expression of inflammatory cytokines and mucus in nasal epithelial cells by inhibiting the activation of NF-κB and MAPK signaling pathways.

Platycodin D, a metabolite of Platycodin grandiflorum, inhibits highly metastatic MDA-MB-231 breast cancer growth in vitro and in vivo by targeting the MDM2 oncogene

The objective of the present study was to explore the in vitro and in vivo anticancer effects of Platycodin D (PD), derived from Platycodin grandiflorum, on highly metastatic MDA-MB-231 breast cancer cells. Using the MTT assay, we found that PD inhibited MDA-MB-231 cell growth in a concentration-dependent manner, with an IC50 value of 7.77±1.86 µM. Further studies showed that PD had anti-proliferative effects and induced cell cycle arrest in the G0/G1 phase. To explore the detailed mechanism(s) by which PD suppressed MDA-MB-231 cell growth, western blot analyses were used to detect the expression levels of proteins related to cell proliferation and survival. The data showed that PD decreased the expression of proteins related to the G0/G1 phases, downregulated the protein expression of MDM2, MDMX, and mutant p53, and increased the expression levels of p21 and p27 in vitro. We verified the effects of PD on the expression of MDM2, MDMX, mutant p53, p21 and p27 using a pcDNA3-Flag-MDM2 plasmid and MDM2 siRNA transfection, and found that PD inhibited MDA-MB-231 cell viability by targeting MDM2 and mutant p53. Compared with the corresponding parental cells, the cells with siRNA-MDM2 transfection had a greater decrease in cell viability and proliferation, while those with pcDNA3-MDM2 plasmid transfection did not show any increase in the effects of PD. We also established a MDA-MB-231 xenograft model in BALB/c nude mice, and found that PD significantly inhibited the growth of MDA-MB-231 xenograft tumors in these mice. The expression levels of various proteins in the tumor tissue exhibited changes similar to those observed in vitro. These findings indicate that PD exerted in vitro and in vivo anticancer effects against MDA-MB-231 breast cancer cells, that PD is a potential MDM2/MDMX inhibitor, and that the anticancer effects of PD were likely associated with its inhibition of these proteins. Our observations help to identify a mechanism by which PD functions as an anti-breast cancer agent.

Proteomic analysis of hepatocellular carcinoma HepG2 cells treated with platycodin D

Platycodin D (PD), a triterpenoid saponin isolated from Platycodonis Radix, is a famous Chinese herbal medicine that has been shown to have anti-proliferative effects in several cancer cell lines. The aim of this study was to determine the changes in cellular proteins after the treatment of hepatocellular carcinoma HepG2 cells with PD using proteomics approaches. The cell viability was determined using the MTT assay. The proteome was analyzed by two-dimensional difference gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Western blot analysis was used to confirm the expression of changed proteins. Our results showed that PD inhibited the proliferation of HepG2 cells in concentration- and time-dependent manners. Sixteen proteins were identified to be up-regulated in PD-treated HepG2 cells, including ATP5H, OXCT1, KRT9, CCDC40, ERP29, RCN1, ZNF175, HNRNPH1, HSP27, PA2G4, PHB, BANF1, TPM3, ECH1, LGALS1, and MYL6. Three proteins (i.e., RPS12, EMG1, and KRT1) decreased in HepG2 cells after treatment with PD. The changes in HSP27 and PHB were further confirmed by Western blotting. In conclusion, our results shed new lights on the mechanisms of action for the anti-cancer activity of PD.

The first EGF domain of coagulation factor IX attenuates cell adhesion and induces apoptosis

Coagulation factor IX (FIX) is an essential plasma protein for blood coagulation. The first epidermal growth factor (EGF) motif of FIX (EGF-F9) has been reported to attenuate cell adhesion to the extracellular matrix (ECM). The purpose of the present study was to determine the effects of this motif on cell adhesion and apoptosis. Treatment with a recombinant EGF-F9 attenuated cell adhesion to the ECM within 10 min. De-adhesion assays with native FIX recombinant FIX deletion mutant proteins suggested that the de-adhesion activity of EGF-F9 requires the same process of FIX activation as that which occurs for coagulation activity. The recombinant EGF-F9 increased lactate dehydrogenase (LDH) activity release into the medium and increased the number of cells stained with annexin V and activated caspase-3, by 8.8- and 2.7-fold respectively, indicating that EGF-F9 induced apoptosis. Activated caspase-3 increased very rapidly after only 5 min of administration of recombinant EGF-F9. Treatment with EGF-F9 increased the level of phosphorylated p38 mitogen-activated protein kinase (MAPK), but not that of phosphorylated MAPK 44/42 or c-Jun N-terminal kinase (JNK). Inhibitors of caspase-3 suppressed the release of LDH. Caspase-3 inhibitors also suppressed the attenuation of cell adhesion and phosphorylation of p38 MAPK by EGF-F9. Our data indicated that EGF-F9 activated signals for apoptosis and induced de-adhesion in a caspase-3 dependent manner.

Platycodin D inhibits B16F10 melanoma metastasis via antiangiogenic activity

Platycodin D inhibits B16F10 melanoma metastasisviaantiangiogenic activity.

Killing cancer with platycodin D through multiple mechanisms

Cancer is a multi-faceted disease comprised of a combination of genetic, epigenetic, metabolic and signalling aberrations which severely disrupt the normal homoeostasis of cell growth and death. Rational developments of highly selective drugs which specifically block only one of the signalling pathways have been associated with limited therapeutic success. Multi-targeted prevention of cancer has emerged as a new paradigm for effective anti-cancer treatment. Platycodin D, a triterpenoid saponin, is one the major active components of the roots of Platycodon grandiflorum and possesses multiple biological and pharmacological properties including, anti-nociceptive, anti-atherosclerosis, antiviral, anti-inflammatory, anti-obesity, immunoregulatory, hepatoprotective and anti-tumour activities. Recently, the anti-cancer activity of platycodin D has been extensively studied. The purpose of this review was to give our perspectives on the current status of platycodin D and discuss its anti-cancer activity and molecular mechanisms which may help the further design and conduct of pre-clinical and clinical trials to develop it successfully into a potential lead drug for oncological therapy. Platycodin D has been shown to fight cancer by inducing apoptosis, cell cycle arrest, and autophagy and inhibiting angiogenesis, invasion and metastasis by targeting multiple signalling pathways which are frequently deregulated in cancers suggesting that this multi-target activity rather than a single effect may play an important role in developing platycodin D into potential anti-cancer drug.