Saikosaponin-d Increases the Radiosensitivity of Hepatoma Cells by Adjusting Cell Autophagy

Advances in the anti-tumor mechanisms of saikosaponin D

Saikosaponin D, a saponin compound, is extracted from Bupleurum and is a principal active component of the plant. It boasts a variety of pharmacologic effects including anti-inflammatory, antioxidant, immunomodulatory, metabolic, and anti-tumor properties, drawing significant attention in anti-tumor research in recent years. Research indicates that saikosaponin D inhibits the proliferation of numerous tumor cells, curbing the progression of cancers such as liver, pancreatic, lung, glioma, ovarian, thyroid, stomach, and breast cancer. Its anti-tumor mechanisms largely involve inhibiting tumor cell proliferation, promoting tumor cell apoptosis, thwarting tumor-cell invasion, and modulating tumor cell autophagy. Moreover, saikosaponin D enhances the sensitivity to anti-tumor drugs and augments body immunity. Given its multi-faceted anti-tumor roles, saikosaponin D offers promising potential in anti-tumor therapy. This paper reviews recent studies on its anti-tumor effects, aiming to furnish new theoretical insights for clinical cancer treatments.

Investigating autophagy and intricate cellular mechanisms in hepatocellular carcinoma: Emphasis on cell death mechanism crosstalk

Hepatocellular carcinoma (HCC) stands as a formidable global health challenge due to its prevalence, marked by high mortality and morbidity rates. This cancer type exhibits a multifaceted etiology, prominently linked to viral infections, non-alcoholic fatty liver disease, and genomic mutations. The inherent heterogeneity of HCC, coupled with its proclivity for developing drug resistance, presents formidable obstacles to effective therapeutic interventions. Autophagy, a fundamental catabolic process, plays a pivotal role in maintaining cellular homeostasis, responding to stressors such as nutrient deprivation. In the context of HCC, tumor cells exploit autophagy, either augmenting or impeding its activity, thereby influencing tumorigenesis. This comprehensive review underscores the dualistic role of autophagy in HCC, acting as both a pro-survival and pro-death mechanism, impacting the trajectory of tumorigenesis. The anti-carcinogenic potential of autophagy is evident in its ability to enhance apoptosis and ferroptosis in HCC cells. Pertinently, dysregulated autophagy fosters drug resistance in the carcinogenic context. Both genomic and epigenetic factors can regulate autophagy in HCC progression. Recognizing the paramount importance of autophagy in HCC progression, this review introduces pharmacological compounds capable of modulating autophagy-either inducing or inhibiting it, as promising avenues in HCC therapy.

An Overview of Traditional Chinese Medicine in the Treatment After Radical Resection of Hepatocellular Carcinoma

According to the Barcelona Clinic Liver Cancer (BCLC) system, radical resection of early stage primary hepatocellular carcinoma (HCC) mainly includes liver transplantation, surgical resection, and radiofrequency ablation (RFA), which yield 5-year survival rates of about 70-79%, 41.3-69.5%, and 40-70%, respectively. The tumor-free 5-year rate for HCC patients undergoing radical resection only reach up to 13.7 months, so the prevention of recurrence after radical resection of HCC is very important for the prognosis of patients. The traditional Chinese medicine (TCM) takes the approach of multitarget and overall-regulation to treat tumors, it can also independently present the "component-target-pathway" related to a particular disease, and its systematic and holistic characteristics can provide a personalized therapy based on symptoms of the patient by treating the patient as a whole. TCM as postoperative adjuvant therapy after radical resection of HCC in Barcelona Clinic liver cancer A or B stages, and the numerous clinical trials confirmed that the efficacy of TCM in the field of HCC has a significant effect, not only improving the prognosis and quality of life but also enhancing patient survival rate. However, with the characteristics of multi-target, multi-component, and multi-pathway, the specific mechanism of Chinese medicine in the treatment of diseases is still unclear. Because of the positive pharmacological activities of TCM in combating anti-tumors, the mechanism studies of TCM have demonstrated beneficial effects on the regulation of immune function, chronic inflammation, the proliferation and metastasis of liver cancer cells, autophagy, and cell signaling pathways related to liver cancer. Therefore, this article reviews the mechanism of traditional Chinese medicine in reducing the recurrence rate of HCC after radical resection.

Doxorubicin resistance in breast cancer is mediated via the activation of FABP5/PPARγ and CaMKII signaling pathway

Breast cancer is the most prevalent malignancy among women. Doxorubicin (Dox) resistance was one of the major obstacles to improving the clinical outcome of breast cancer patients. The purpose of this study was to investigate the relationship between the FABP signaling pathway and Dox resistance in breast cancer. The resistance property of MCF-7/ADR cells was evaluated employing CCK-8, Western blot (WB), and confocal microscopy techniques. The glycolipid metabolic properties of MCF-7 and MCF-7/ADR cells were identified using transmission electron microscopy, PAS, and Oil Red O staining. FABP5 and CaMKII expression levels were assessed through GEO and WB approaches. The intracellular calcium level was determined by flow cytometry. Clinical breast cancer patient's tumor tissues were evaluated by immunohistochemistry to determine FABP5 and p-CaMKII protein expression. In the presence or absence of FABP5 siRNA or the FABP5-specific inhibitor SBFI-26, Dox resistance was investigated utilizing CCK-8, WB, and colony formation methods, and intracellular calcium level was examined. The binding ability of Dox was explored by molecular docking analysis. The results indicated that the MCF-7/ADR cells we employed were Dox-resistant MCF-7 cells. FABP5 expression was considerably elevated in MCF-7/ADR cells compared to parent MCF-7 cells. FABP5 and p-CaMKII expression were increased in resistant patients than in sensitive individuals. Inhibition of the protein expression of FABP5 by siRNA or inhibitor increased Dox sensitivity in MCF-7/ADR cells and lowered intracellular calcium, PPARγ, and autophagy. Molecular docking results showed that FABP5 binds more powerfully to Dox than the known drug resistance-associated protein P-GP. In summary, the PPARγ and CaMKII axis mediated by FABP5 plays a crucial role in breast cancer chemoresistance. FABP5 is a potentially targetable protein and therapeutic biomarker for the treatment of Dox resistance in breast cancer.

Endoplasmic reticulum stress regulates autophagic response that is involved in Saikosaponin a-induced liver cell damage

Saikosaponin a (Ssa) is an active ingredient of the Chinese herbal plant Radix Bupleuri (RB) and has severe hepatotoxicity. However, biomolecular mechanisms involved in Ssa-induced hepatotoxicity are not yet entirely clear. Previous studies reported that Ssd (an isomer of Ssa) as a sarcoplasmic/endoplasmic reticulum calcium ATPase (SERCA) inhibitor can induce autophagy in apoptotic defective cells, leading to autophagy-dependent cell death. Therefore, we speculate that endoplasmic reticulum (ER) stress and autophagy may also play an important role in Ssa-induced hepatocyte death. This study aimed to explore the connection between ER stress and autophagy and Ssa-induced hepatotoxicity. Experiments in vitro showed that the cell viability of L-02 cells in the Ssa treatment group decreased, the level of autophagy marker LC3-II/LC3-I and Beclin1 increased, the level of p62 decreased, the colocalization of autophagosome and lysosome increased, and the cell viability was significantly increased after the application of autophagy inhibitors 3-MA. In addition, SSa can induce ER stress in L-02 cells in vitro. Further studies demonstrated that SSa activated the PERK/eIF2α/ATF4/CHOP pathway, IRE1-TRAF2 pathway, ATF6 pathway, and AMPK/mTOR pathway associated with ER stress. Application of ER stress inhibitors 4-PBA can significantly down-regulate the level of autophagy and improve cell viability. Results of in vivo experiments showed that treatment with 150 and 300 mg/kg Ssa significantly elevated the liver/body weight ratio and caused histological injury in mice liver. Furthermore, Ssa treatment induced significantly downregulated p62 expression but upregulated LC3-II, CHOP, and GRP78 expression in mice livers. Taken together, our results showed that SSa can activate endoplasmic reticulum stress, promote toxic autophagy, and then induce cell death. We revealed an alternative mechanism involving autophagy and ERs, by which Ssa induced hepatotoxicity.

Targeting and regulation of autophagy in hepatocellular carcinoma: revisiting the molecular interactions and mechanisms for new therapy approaches

Autophagy is an evolutionarily conserved process that plays a role in regulating homeostasis under physiological conditions. However, dysregulation of autophagy is observed in the development of human diseases, especially cancer. Autophagy has reciprocal functions in cancer and may be responsible for either survival or death. Hepatocellular carcinoma (HCC) is one of the most lethal and common malignancies of the liver, and smoking, infection, and alcohol consumption can lead to its development. Genetic mutations and alterations in molecular processes can exacerbate the progression of HCC. The function of autophagy in HCC is controversial and may be both tumor suppressive and tumor promoting. Activation of autophagy may affect apoptosis in HCC and is a regulator of proliferation and glucose metabolism. Induction of autophagy may promote tumor metastasis via induction of EMT. In addition, autophagy is a regulator of stem cell formation in HCC, and pro-survival autophagy leads to cancer cell resistance to chemotherapy and radiotherapy. Targeting autophagy impairs growth and metastasis in HCC and improves tumor cell response to therapy. Of note, a large number of signaling pathways such as STAT3, Wnt, miRNAs, lncRNAs, and circRNAs regulate autophagy in HCC. Moreover, regulation of autophagy (induction or inhibition) by antitumor agents could be suggested for effective treatment of HCC. In this paper, we comprehensively review the role and mechanisms of autophagy in HCC and discuss the potential benefit of targeting this process in the treatment of the cancer. Video Abstract.

Chemotherapeutic Potential of Saikosaponin D: Experimental Evidence

Saikosaponin D (SSD), an active compound derived from the traditional plant Radix bupleuri, showcases potential in disease management owing to its antioxidant, antipyretic, and anti-inflammatory properties. The toxicological effects of SSD mainly include hepatotoxicity, neurotoxicity, hemolysis, and cardiotoxicity. SSD exhibits antitumor effects on multiple targets and has been witnessed in diverse cancer types by articulating various cell signaling pathways. As a result, carcinogenic processes such as proliferation, invasion, metastasis, and angiogenesis are inhibited, whereas apoptosis, autophagy, and differentiation are induced in several cancer cells. Since it reduces side effects and strengthens anti-cancerous benefits, SSD has been shown to have an additive or synergistic impact with chemo-preventive medicines. Regardless of its efficacy and benefits, the considerations of SSD in cancer prevention are absolutely under-researched due to its penurious bioavailability. Diverse studies have overcome the impediments of inadequate bioavailability using nanotechnology-based methods such as nanoparticle encapsulation, liposomes, and several other formulations. In this review, we emphasize the association of SSD in cancer therapeutics and the discussion of the mechanisms of action with the significance of experimental evidence.

Natural-Product-Mediated Autophagy in the Treatment of Various Liver Diseases

Autophagy is essential for the maintenance of hepatic homeostasis, and autophagic malfunction has been linked to the pathogenesis of substantial liver diseases. As a popular source of drug discovery, natural products have been used for centuries to effectively prevent the progression of various liver diseases. Emerging evidence has suggested that autophagy regulation is a critical mechanism underlying the therapeutic effects of these natural products. In this review, relevant studies are retrieved from scientific databases published between 2011 and 2022, and a novel scoring system was established to critically evaluate the completeness and scientific significance of the reviewed literature. We observed that numerous natural products were suggested to regulate autophagic flux. Depending on the therapeutic or pathogenic role autophagy plays in different liver diseases, autophagy-regulative natural products exhibit different therapeutic effects. According to our novel scoring system, in a considerable amount of the involved studies, convincing and reasonable evidence to elucidate the regulatory effects and underlying mechanisms of natural-product-mediated autophagy regulation was missing and needed further illustration. We highlight that autophagy-regulative natural products are valuable drug candidates with promising prospects for the treatment of liver diseases and deserve more attention in the future.

Saikosaponin d Alleviates Liver Fibrosis by Negatively Regulating the ROS/NLRP3 Inflammasome Through Activating the ERβ Pathway

Background and aims: Saikosaponin d (SSd) has a steroidal structure and significant anti-inflammatory effects. The purpose of this study was to explore the mechanism underlying SSd’s inhibitory effects on liver fibrosis.

Methods: Wild-type and estrogen receptor knockout (ERKO) mice were treated with CCl₄ to establish liver fibrosis mouse models. The effects of SSd on hepatic fibrogenesis were studied in these mouse models. Hepatic stellate cells (HSCs) were activated by H₂O₂ to investigate the potential molecular mechanisms. The establishment of the models and the degrees of inflammation and liver tissue fibrosis were evaluated by detecting changes in serum liver enzymes and liver histopathology. The expression of α-SMA and TGF-β1 was determined by immunohistochemistry. The expression and significance of NLRP3 inflammasome proteins were explored by RT-PCR and Western blotting analyses. The mitochondrial ROS-related indexes were evaluated by MitoSOX Red.

Results: In wild-type and ERKO mice treated with CCl₄, the fluorescence expression of mitochondrial ROS was up-regulated, while the mitochondrial membrane potential and ATP content were decreased, suggesting that the mitochondria were damaged. In addition, the expression of NLRP3 inflammatory bodies and fibrosis markers (α-SMA, TGF-β, TIMP-1, MMP-2, and Vimentin) in liver tissue increased. Furthermore, the above indexes showed the same expression trend in activated HSCs. In addition, the peripheral serum ALT and AST levels increased in CCl₄-induced liver injury model mice. And HE staining showed a large number of inflammatory cell infiltration in the liver of model mice. Picric acid-Sirius staining and Masson staining showed that there was significant collagen fibrous tissue deposition in mice liver sections. IHC and WB detection confirmed that the expression of α-SMA and TGF-β1 increased. Liver fibrosis scores were also elevated. Then, after SSd intervention, the expression of ROS in wild-type mice and αERKO mice decreased, mitochondrial membrane potential recovered, ATP level increased, NLRP3 inflammasome and fibrosis indexes decreased, liver enzyme levels decreased, and liver pathology showed liver inflammation. The damage and collagen deposition were significantly relieved, the expression of α-SMA and TGF-β1 was decreased, and the fibrosis score was also decreased. More importantly, the effect of SSd in alleviating liver injury and liver fibrosis had no effect on βERKO mice.

Conclusion: SSd alleviated liver fibrosis by negatively regulating the ROS/NLRP3 inflammasome through activating the ERβ pathway. By establishing liver fibrosis models using wild-type and ERKO mice, we demonstrated that SSd could alleviate liver fibrosis by inhibiting the ROS/NLRP3 inflammasome axis through activating the ERβ pathway.

Targeting autophagy in ethnomedicine against human diseases

ETHNOPHARMACOLOGICAL RELEVANCE

In the past five years, ethnopharmacy-based drugs have been increasingly used in clinical practice. It has been reported that hundreds of ethnopharmacy-based drugs can modulate autophagy to regulate physiological and pathological processes, and ethnomedicines also have certain therapeutic effects on illnesses, revealing the important roles of these medicines in regulating autophagy and treating diseases.

AIM OF THE STUDY

This study reviews the regulatory effects of natural products on autophagy in recent years, and discusses their pharmacological effects and clinical applications in the process of diseases. It provides a preliminary literature basis and reference for the research of plant drugs in the regulation of autophagy.

MATERIALS AND METHODS

A comprehensive systematic review in the fields of relationship between autophagy and ethnomedicine in treating diseases from PubMed electronic database was performed. Information was obtained from documentary sources.

RESULTS

We recorded some illnesses associated with autophagy, then classified them into different categories reasonably. Based on the uses of these substances in different researches of diseases, a total of 80 active ingredients or compound preparations of natural drugs were searched. The autophagy mechanisms of these substances in the treatments of divers diseases have been summarized for the first time, we also looked forward to the clinical application of some of them.

CONCLUSIONS

Autophagy plays a key function in lots of illnesses, the regulation of autophagy has become one of the important means to prevent and treat these diseases. About 80 compounds and preparations involved in this review have been proved to have therapeutic effects on related diseases through the mechanism of autophagy. Experiments in vivo and in vitro showed that these compounds and preparations could treat these diseases by regulating autophagy. The typical natural products curcumin and tripterine have powerful roles in regulating autophagy and show good and diversified curative effects.

Saikosaponin D: review on the antitumour effects, toxicity and pharmacokinetics

CONTEXT

Bupleuri Radix, the dried root of Bupleurum chinense DC and Bupleurum scorzonerifolium Willd (Apiaceae), is an important medicinal herb widely used to treat cancers for hundreds of years in Asian countries. As the most antitumour component but also the main toxic component in Bupleuri Radix, saikosaponin D (SSD) has attracted extensive attention. However, no summary studies have been reported on the antitumour effects, toxicity and pharmacokinetics of this potential natural anticancer substance.

OBJECTIVE

To analyse and summarise the existing findings regarding to the antitumour effects, toxicity and pharmacokinetics of SSD.

MATERIALS AND METHODS

We collected relevant information published before April 2021 by conducting a search of literature available in various online databases including PubMed, Science Direct, CNKI, Wanfang database and the Chinese Biological Medicine Database. Bupleurum, Bupleuri Radix, saikosaponin, saikosaponin D, tumour, toxicity, and pharmacokinetics were used as the keywords.

RESULTS

The antitumour effects of SSD were multi-targeted and can be realised through various mechanisms, including inhibition of proliferation, invasion, metastasis and angiogenesis, as well as induction of cell apoptosis, autophagy, and differentiation. The toxicological effects of SSD mainly included hepatotoxicity, neurotoxicity, haemolysis and cardiotoxicity. Pharmacokinetic studies demonstrated that SSD had the potential to alter the pharmacokinetics of some drugs for its influence on CYPs and P-gp, and the oral bioavailability and actual pharmacodynamic substances in vivo of SSD are still controversial.

CONCLUSIONS

SSD is a potentially effective and relatively safe natural antitumour substance, but more research is needed, especially in vivo antitumour effects and pharmacokinetics of the compound.

Saikosaponin D Inhibits the Proliferation and Promotes the Apoptosis of Rat Hepatic Stellate Cells by Inducing Autophagosome Formation

Objective

This study aimed to investigate the effects of saikosaponin D (SSd) on the proliferation and apoptosis of the HSC-T6 hepatic stellate cell line and determine the key pathway that mediates SSd's function.

Methods

Cell viability was detected using the CCK-8 kit. The EdU kit and flow cytometry were used to examine cell proliferation. The Annexin V-FITC/PI double staining kit and flow cytometry were used to examine cell apoptosis. Western blot analysis was performed to analyze the expression levels of LC3, Ki67, cleaved caspase 3, Bax, and Bcl2. Autophagosome formation was detected by LC3-GFP adenovirus transfection.

Results

SSd inhibits the proliferation and promotes the apoptosis of acetaldehyde-activated HSC-T6 cells. SSd treatment increased the expression of cleaved caspase 3 and Bax but reduced that of Ki67 and Bcl2. The same concentration of SSd barely influenced the growth of normal rat liver BRL-3A cells. SSd upregulated LC3-II expression and induced autophagosome formation. Autophagy agonist rapamycin had the same effect as SSd and autophagy inhibitor 3-methyladenine could neutralize the effect of SSd in acetaldehyde-activated HSC-T6 cells.

Conclusions

SSd could inhibit the proliferation and promote the apoptosis of HSC-T6 cells by inducing autophagosome formation.

MiR-452-5p mediates the proliferation, migration and invasion of hepatocellular carcinoma cells via targeting COLEC10

Objective: This study explored the potential function of miR-452-5p in hepatocellular carcinoma (HCC) and clarified the mechanism underlying HCC progression. Materials & methods: Real-time quantitative PCR was used to detect miR-452-5p and COLEC10 mRNA expression in HCC, western blot was performed to test COLEC10 protein expression. The regulatory mechanism of miR-452-5p/COLEC10 in HCC cells was explored using CCK-8, wound healing assay, Transwell and dual-luciferase reporter assay. Results: MiR-452-5p was greatly upregulated in HCC cells, and it served as an oncogene playing an active role in HCC cell proliferation, migration and invasion. COLEC10 was identified as the target of miR-452-5p in HCC attenuating the promoting effect of miR-452-5p on HCC cells upon overexpression. Conclusion: MiR-452-5p can promote the progression of HCC via targeting COLEC10.

Saikosaponin-d increases radiation-induced apoptosis of hepatoma cells by promoting autophagy via inhibiting mTOR phosphorylation

Objective: The aim of this study was to analyze the effects of saikosaponin-d (SSd) on autophagy activity and radiosensitivity of hepatoma cells, and to elucidate its related molecular mechanisms. Methods: The growth of SMMC-7721 and MHCC97L hepatoma cells were detected by clonal formation and survival fraction. Flow cytometry was used to detect the changes of apoptosis of hepatoma cells. The morphological changes of autophagy of hepatoma cells were observed by transmission electron microscopy and were further quantitatively detected by laser confocal microscopy. The expressions of related proteins were detected by Western blotting. Results: SSd can significantly increase the apoptosis of hepatoma cells induced by radiation and inhibit the proliferation of hepatoma cells. The addition of the autophagy inhibitor chloroquine (CQ) or an mTOR agonist (MHY1485), which could reduce the promoting effect of SSd on radiation-induced apoptosis and inhibitory effect on the proliferation of hepatoma cells. Transmission electron microscopy and confocal microscopy results also showed that the number of autophagosomes was significantly higher in the radiation and SSd co-treatment group than in the radiotherapy or SSd alone group; however, the effect of SSd on autophagy in hepatoma cells was decreased after adding MHY1485, siRNA-P53 or AMPK inhibitor (Compound C). Western blot analysis showed that after the addition of SSd, the phosphorylation of mTOR was significantly decreased by radiation, the expression of the autophagy-related proteins LC3-II and Beclin-1 was increased, p62 was decreased, and the expression of cleaved caspase-3 and cleaved PARP was enhanced; this effect of SSd was partially reversed after the addition of MHY1485, siRNA-P53 or Compound C. Conclusions: SSd increases radiation-induced apoptosis of hepatoma cells by promoting autophagy via inhibiting mTOR phosphorylation and providing a possible potential approach for radiosensitization therapy of liver cancer.

Effects of saikosaponin-d on CYP3A4 in HepaRG cell and protein-ligand docking study

Saikosaponin-d (SSd) is a major bioactive triterpenoid saponin extracted from Bupleurum, which has anti-inflammatory, anticancer, antioxidative and anti-hepatic fibrosis effects. Due to the effects of Bupleurum-related formulations on cytochrome P450 (CYPs) expression still remain unclear, the combination therapies involved formulations containing Bupleurum may sometimes lead to unexpected drug-drug interactions in clinical practice. These interactions can limit the clinical applications of related formulations. In this study, we tried to explore the effects of SSd on CYP3A4 mRNA, protein expression and the enzyme activity in HepaRG cells by real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR), Western blot (WB) and HPLC method, respectively. The interaction between SSd and CYP3A4 was analysed by molecular docking. HepaRG cells were cultured with different concentrations of SSd (0.5, 1, 5 and 10 μmol/L) for 72 hours. It is revealed that SSd can inhibit CYP3A4 mRNA and its protein expression, and also the enzyme activity. Molecular docking study demonstrated that SSd can bind to several key active sites of amino acid residues of CYP3A4 protein with hydrogen bonds and hydrophobic interactions. Thus, drug-drug interactions resulted by SSd inhibiting CYP3A4 need attention when formulations containing SSd or Bupleurum are co-administrated with drugs metabolized by CYP3A4.

Effects of Saikosaponin D on CYP1A2 and CYP2D6 in HepaRG Cells

Background

Bupleurum is one of the most important traditional Chinese medicines and an ingredient in many compound preparations. It is widely used together with other drugs in clinical practice, and thus there is great potential for drug–drug interactions. Saikosaponin D (SsD) is a major bioactive triterpenoid saponin extracted from Bupleurum with anti-inflammatory, anticancer, antioxidative, and antihepatic fibrosis effects. Effects of the main components of Bupleurum on cytochromes P450 (CYPs) need to be clarified in the clinical application of combination therapies of formulations containing SsD or Bupleurum.

Purpose

This study aimed to investigate the effects of SsD on the CYP1A2 and CYP2D6 mRNAs, protein expression, and relative enzyme activities in HepaRG cells.

Methods

HepaRG cells were cultured with SsD at concentrations of 0.5, 1, 5 and 10 μM for 72 hours. mRNA and protein expression of CYP1A2 and CYP2D6 were analyzed with real-time PCR and Western blot analysis. Relative enzyme activities were analyzed with HPLC based on consumption of the specific probe substrate.

Results

SsD significantly induced expression of mRNA and increased relative activity of CYP1A2 in HepaRG cells after the cells had been treated with SsD at concentrations of 1, 5 and 10 μM. SsD also induced protein expression of CYP1A2 at concentrations of 5 and 10 μM. SsD exhibited an inductive effect on CYP2D6 mRNA and protein expression, while increasing the relative activity of CYP2D6 at concentrations of 5 and 10 μM.

Conclusion

This study is the first to investigate the effect of SsD on CYP1A2 and CYP2D6 in HepaRG cells, and the results may provide some useful information on potential drug–drug interactions related to clinical preparations containing SsD or Bupleurum.

PSPH induces cell autophagy and promotes cell proliferation and invasion in the hepatocellular carcinoma cell line Huh7 via the AMPK/mTOR/ULK1 signaling pathway

Phosphoserine phosphatase (PSPH), a key enzyme of the l-serine synthesis pathway, has been involved in cancer progression and survival. However, limited evidence revealed the PSPH influence on hepatocellular carcinoma (HCC). Herein, we observed that PSPH expression was upregulated in both HCC tissues and cell lines, which was determined by western blotting. TCGA database showed that the PSPH protein levels were significantly upregulated and affected patient survival rates in HCC. Then gain- and loss-of-function manipulations were performed by transfection with a pcDNA-PSPH expression vector or a specific short interfering RNA against PSPH in Huh7 cells. Huh7 cell proliferation, stemness, invasion, and apoptosis were assessed by using CCK-8 test, colony formation assay, Transwell assay, and Flow cytometry analysis, respectively, and levels of autophagy-related proteins were detected by using western blotting. The results showed that PSPH could induce Huh7 cell autophagy, promote cell proliferation and invasion, and inhibit apoptosis. The knockdown of PSPH could inhibit Huh7 cell proliferation, invasion, and autophagy. Furthermore, PSPH activated Liver kinase B1 (LKB1) and TGF beta-activated kinase 1 (TAK1), affected the adenosine 5'-monophosphate-activated protein kinase (AMPK)/mTOR/ULK1 signaling pathway, but could not activate calcium/calmodulin-dependent protein kinase kinase (CaMKK) in Huh7 cells. Inhibition of either LKB1, TAK1, or AMPK could eliminate the effect of PSPH overexpression on Huh7 cell behaviors. However, inhibition of CaMKK could not influence the effect of PSPH overexpression on Huh7 cell behaviors. In conclusion, PSPH could induce autophagy, promote proliferation and invasion, and inhibit apoptosis in HCC cells via the AMPK/mTOR/ULK1 signaling pathway.

Saikosaponin D Inhibits Proliferation and Promotes Apoptosis Through Activation of MKK4-JNK Signaling Pathway in Pancreatic Cancer Cells

Introduction

Pancreatic cancer remains one of the most lethal malignancies and has few treatment options. Saikosaponin D (SSD), a major bioactive triterpene saponin isolated from Bupleurum chinense, has been reported to exert cytotoxicity properties toward many cancer cells. However, the effects of SSD on pancreatic cancer have been little scrutinized.

Methods

Here, we investigated the effect of SSD on the proliferation and apoptosis of human pancreatic cancer BxPC3 and PANC1 cells and the mouse pancreatic cancer cell line Pan02. Cell viability was determined by MTT assays and cell apoptosis analyzed by DAPI staining and flow cytometry. Expression levels of apoptosis-regulating markers and activity of the MKK4–JNK signaling pathway were determined by Western blotting. The inhibitor SP600125 was applied to confirm the role of the JNK pathway in SSD efficiency.

Results

SSD significantly inhibited the proliferation of BxPC3, PANC1, and Pan02 cells in a concentration- and time-dependent manner. Flow-cytometry analysis indicated obvious apoptosis induction after SSD exposure. Furthermore, SSD significantly triggered cleavage of caspase 3 and caspase 9 proteins and increased the expression of FoxO3a. In addition, activity of the MKK4–JNK pathway was dramatically increased after treatment with SSD in BxPC3 cells. SSD obviously stimulated phosphorylation of JNK, cJun, and SEK1/MKK4 proteins within 30 minutes. The addition of SP600125 blocked the activation of SSD on the MKK4–JNK regulatory pathway and reversed the effects of SSD on proliferation inhibition and apoptosis induction in BxPC3 cells.

Conclusion

These results revealed that SSD was capable of suppressing tumor growth and promoting apoptosis of pancreatic cancer cells via targeting the MKK4–JNK signaling pathway, indicating the possibility of further developing SSD as a potential therapeutic candidate for pancreatic cancer.