Sinomenine inhibits the growth of melanoma by enhancement of autophagy via PI3K/AKT/mTOR inhibition

Sinomenine exerts a neuroprotective effect on PD mouse model through inhibiting PI3K/AKT/mTOR pathway to enhance autophagy

BACKGROUND

Parkinson's disease (PD), as a chronic and progressive neurodegenerative disease, is associated with autophagy. This study focused on the regulation of sinomenine (SN) on autophagy in PD and its related mechanism.

METHODS

The PD mouse model was constructed by MPTP inducement, and the mouse motor function after modeling and SN treatment was examined by rotarod, grip strength, and foot printing tests. Tyrosine hydroxylase (TH)/LC3B-positive neurons in the substantia nigra pars compacta of mouse brains were detected by immunofluorescence. The expressions of proteins related to autophagy (Beclin1, p62, LC3-I and LC3-II) and phosphorylated phosphoinositide 3-kinase (PI3K)/AKT/mechanistic target of rapamycin kinase (mTOR) signaling pathway were measured by western blot. Rescue experiments were performed to determine the effects of MHY1485 (mTOR activator) on SN-treated PD mice.

RESULTS

SN potentiated the motor ability in PD mice, promoted the survival of dopaminergic neurons, increased the protein expression level of Beclin1, LC3-II/LC3-I ratio and LC3B-positive neurons, lowered the protein expression level of p62 and inactivated PI3K/AKT/mTOR pathway in the substantia nigra tissue of mouse brains. Moreover, MHY1485 reversed the above effects of SN on PD mice via reactivating PI3K/AKT/mTOR pathway.

CONCLUSION

SN augments the autophagy of dopaminergic neurons via inhibiting the PI3K/AKT/mTOR pathway and exerts a neuroprotective effect on PD mice.

Sinomenine increases osteogenesis in mice with ovariectomy-induced bone loss by modulating autophagy

BACKGROUND

A decreased autophagic capacity of bone marrow mesenchymal stromal cells (BMSCs) has been suggested to be an important cause of decreased osteogenic differentiation. A pharmacological increase in autophagy of BMSCs is a potential therapeutic option to increase osteoblast viability and ameliorate osteoporosis.

AIM

To explore the effects of sinomenine (SIN) on the osteogenic differentiation of BMSCs and the underlying mechanisms.

METHODS

For in vitro experiments, BMSCs were extracted from sham-treated mice and ovariectomized mice, and the levels of autophagy markers and osteogenic differentiation were examined after treatment with the appropriate concentrations of SIN and the autophagy inhibitor 3-methyladenine. In vivo, the therapeutic effect of SIN was verified by establishing an ovariectomy-induced mouse model and by morphological and histological assays of the mouse femur.

RESULTS

SIN reduced the levels of AKT and mammalian target of the rapamycin (mTOR) phosphorylation in the phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR signaling pathway, inhibited mTOR activity, and increased autophagy ability of BMSCs, thereby promoting the osteogenic differentiation of BMSCs and effectively alleviating bone loss in ovariectomized mice in vivo.

CONCLUSION

The Chinese medicine SIN has potential for the treatment of various types of osteoporosis, bone homeostasis disorders, and autophagy-related diseases.

Qufeng tongluo decoction decreased proteinuria in diabetic mice by protecting podocytes via promoting autophagy

Background

Diabetic kidney disease (DKD) is one of diabetic complications, which has become the leading cause of end-stage kidney disease. In addition to angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker(ACEI/ARB) and sodium-glucose cotransporter-2 inhibitor (SGLT2i), traditional Chinese medicine (TCM) is an effective alternative treatment for DKD. In this study, the effect of Qufeng Tongluo (QFTL) decoction in decreasing proteinuria has been observed and its mechanism has been explored based on autophagy regulation in podocyte.

Methods

In vivo study, db/db mice were used as diabetes model and db/m mice as blank control. Db/db mice were treated with QFTL decoction, rapamycin, QFTL + 3-Methyladenine (3-MA), trehalose, chloroquine (CQ) and QFTL + CQ. Mice urinary albumin/creatinine (UACR), nephrin and autophagy related proteins (LC3 and p62) in kidney tissue were detected after intervention of 9 weeks. Transcriptomics was operated with the kidney tissue from model group and QFTL group. In vitro study, mouse podocyte clone-5 (MPC-5) cells were stimulated with hyperglycemic media (30 mmol/L glucose) or cultured with normal media. High-glucose-stimulated MPC-5 cells were treated with QFTL freeze-drying powder, rapamycin, CQ, trehalose, QFTL+3-MA and QFTL + CQ. Cytoskeletal actin, nephrin, ATG-5, ATG-7, Beclin-1, cathepsin L and cathepsin B were assessed. mRFP-GFP-LC3 was established by stubRFP-sensGFP-LC3 lentivirus transfection.

Results

QFTL decoction decreased the UACR and increased the nephrin level in kidney tissue and high-glucose-stimulated podocytes. Autophagy inhibitors, including 3-MA and chloroquine blocked the effects of QFTL decoction. Further study showed that QFTL decoction increased the LC3 expression and relieved p62 accumulation in podocytes of db/db mice. In high-glucose-stimulated MPC-5 cells, QFTL decoction rescued the inhibited LC3 and promoted the expression of ATG-5, ATG-7, and Beclin-1, while had no effect on the activity of cathepsin L and cathepsin B. Results of transcriptomics also showed that 51 autophagy related genes were regulated by QFTL decoction, including the genes of ATG10, SCOC, ATG4C, AMPK catalytic subunit, PI3K catalytic subunit, ATG3 and DRAM2.

Conclusion

QFTL decoction decreased proteinuria and protected podocytes in db/db mice by regulating autophagy.

Ginsenoside Rg1 Induces Autophagy in Colorectal Cancer through Inhibition of the Akt/mTOR/p70S6K Pathway

This study aimed to elucidate the anti-colon cancer mechanism of ginsenoside Rg1 in vitro and in vivo. Cell viability rate was detected using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) tetrazolium assay. The inhibitory effect of ginsenoside Rg1 against CT26 cell proliferation gradually increased with increasing concentration. The in vivo experiments also demonstrated an antitumor effect. The monodansylcadaverine (MDC), transmission electron microscopy (TEM), and expression of autophagy marker proteins confirmed that ginsenoside Rg1 induced autophagy in vitro. Ginsenoside Rg1 induced autophagy death of CT26 cells, but this effect could be diminished by autophagy inhibitor (3-methyladenine, 3-MA). Additionally, in a xenograft model, immunohistochemical analysis of tumor tissues showed that the LC3 and Beclin-1 proteins were highly expressed in the tumors from the ginsenoside Rg1-treated nude mice, confirming that ginsenoside Rg1 also induced autophagy in vivo. Furthermoer, both in vivo and in vitro, the protein expressions of p-Akt, p-mTOR, and p-p70S6K were inhibited by ginsenoside Rg1, which was verified by Akt inhibitors. These results indicated that the mechanism of ginsenoside Rg1 against colon cancer was associated with autophagy through inhibition of the Akt/mTOR/p70S6K signaling pathway.

Bioactivities and Mechanisms of Action of Sinomenine and Its Derivatives: A Comprehensive Review

Sinomenine, an isoquinoline alkaloid extracted from the roots and stems of Sinomenium acutum, has been extensively studied for its derivatives as bioactive agents. This review concentrates on the research advancements in the biological activities and action mechanisms of sinomenine-related compounds until November 2023. The findings indicate a broad spectrum of pharmacological effects, including antitumor, anti-inflammation, neuroprotection, and immunosuppressive properties. These compounds are notably effective against breast, lung, liver, and prostate cancers, exhibiting IC50 values of approximately 121.4 nM against PC-3 and DU-145 cells, primarily through the PI3K/Akt/mTOR, NF-κB, MAPK, and JAK/STAT signaling pathways. Additionally, they manifest anti-inflammatory and analgesic effects predominantly via the NF-κB, MAPK, and Nrf2 signaling pathways. Utilized in treating rheumatic arthritis, these alkaloids also play a significant role in cardiovascular and cerebrovascular protection, as well as organ protection through the NF-κB, Nrf2, MAPK, and PI3K/Akt/mTOR signaling pathways. This review concludes with perspectives and insights on this topic, highlighting the potential of sinomenine-related compounds in clinical applications and the development of medications derived from natural products.

Oncogenic DNA methyltransferase 1 activates the PI3K/AKT/mTOR signalling by blocking the binding of HSPB8 and BAG3 in melanoma

Abnormal DNA methylation has been observed in multiple malignancies, including melanoma. In this study, we initially noticed the overexpression of DNA methyltransferase 1 (DNMT1) in melanoma samples in bioinformatics analysis and, subsequently, validated it in the purchased melanoma cell lines. After treatment with short-hairpin RNAs or Decitabine (a DNA methylation inhibitor), silencing of DNMT1 was demonstrated to suppress cell viability and invasive and migratory potentials as well as to augment apoptosis and autophagy in melanoma cells. To further explore the downstream mechanisms, we revealed that DNMT1 inhibited HSPB8 expression through augmenting HSPB8 methylation, thereby suppressing the binding between HSPB8 and BAG3. Then, we elucidated through a series of gain- and loss- of function assays that the interplay of HSPB8 and BAG3 blocked the PI3K/AKT/mTOR pathway, thereby repressing the malignant phenotypes of melanoma cells and contributing to melanoma cell apoptosis and autophagy. We further established a mouse model of melanoma and substantiated that DNMT1 enhanced the in vivo tumorigenesis of melanoma cells via activation of the PI3K/AKT/mTOR pathway through repressing the binding between HSPB8 and BAG3. Taken together, our data supported that DNMT1 repressed the binding between HSPB8 and BAG3 and activated the PI3K/AKT/mTOR pathway, thus playing a tumour-promoting role in melanoma.

Development of PI3Kα inhibitors for tumor therapy

The PI3K/AKT/mTOR signaling pathway is well known to be involved in cell growth, proliferation, metabolism and other cellular physiological processes. Abnormal activation of this pathway is closely related to tumorigenesis and metastasis. As the starting node of the pathway, PI3K is known to contain 4 isoforms, including PI3Kα, a heterodimer composed of the catalytic subunit p110α and the regulatory subunit p85. PIK3CA, which encodes p110α, is frequently mutated in cancer, especially breast cancer. Abnormal activation of PI3Kα promotes cancer cell proliferation, migration, invasion, and angiogenesis; therefore, PI3Kα has become a key target for the development of anticancer drugs. The hinge region and the region of the mutation site in the PI3Kα protein are important for designing PI3Kα-specific inhibitors. As the group shared by the most PI3Kα-specific inhibitors reported thus far, carboxamide can produce hydrogen bonds with Gln859 and Ser854. Gln859 is specific to the p110α protein in producing hydrogen bond interactions with PI3Kα-specific inhibitors and this is a key point for designing PI3Kα inhibitors. To date, alpelisib is the only PI3Kα inhibitor approved for the treatment of breast cancer. Several other PI3Kα inhibitors are under evaluation in clinical trials. In this review, we briefly describe PI3Kα and its role in tumorigenesis, summarize the clinical trial results of some PI3Kα inhibitors as well as the synthetic routes of alpelisib, and finally give our proposal for the development of novel PI3Kα inhibitors for tumor therapy. HighlightsWe summarize the progress of PI3Kα and PI3Kα inhibitors in cancer from the second half of the 20th century to the present.We describe the clinical trial results of PI3Kα inhibitors as well as the synthetic routes of the only approved PI3Kα inhibitor alpelisib.Crystal structure of alpelisib bound to the PI3Kα receptor binding domain.This review gives proposal for the development of novel PI3Kα inhibitors and will serve as a complementary summary to other reviews in the research field of PI3K inhibitors.Communicated by Ramaswamy H. Sarma.

TRAF6 regulates autophagy and apoptosis of melanoma cells through c-Jun/ATG16L2 signaling pathway

Autophagy and apoptosis are essential processes that participate in cell death and maintain cellular homeostasis. Dysregulation of these biological processes results in the development of diseases, including cancers. Therefore, targeting the interaction between apoptosis and autophagy offers a potential strategy for cancer therapy. Melanoma is the most lethal skin cancer. We previously found that tumor necrosis factor receptor-associated factor 6 (TRAF6) is overexpressed in melanoma and benefits the malignant phenotype of melanoma cells. Additionally, TRAF6 promotes the activation of cancer-associated fibroblasts in melanoma. However, the role of TRAF6 in autophagy and apoptosis remains unclear. In this study, we found that knockdown of TRAF6 induced both apoptosis and autophagy in melanoma cells. Transcriptomic data and real-time PCR analysis demonstrated reduced expression of autophagy related 16 like 2 (ATG16L2) in TRAF6-deficient melanoma cells. ATG16L2 knockdown resulted in increased autophagy and apoptosis. Mechanism studies confirmed that TRAF6 regulated ATG16L2 expression through c-Jun. Importantly, targeting TRAF6 with cinchonine, a TRAF6 inhibitor, effectively suppressed the growth of melanoma cells by inducing autophagy and apoptosis through the TRAF6/c-Jun/ATG16L2 signaling pathway. These findings highlight the pivotal role of TRAF6 in regulating autophagy and apoptosis in melanoma, emphasizing its significance as a novel therapeutic target for melanoma treatment.

Advances in mitophagy and mitochondrial apoptosis pathway-related drugs in glioblastoma treatment

Glioblastoma (GBM) is the most common malignant tumor of the central nervous system (CNS). It is a leading cause of death among patients with intracranial malignant tumors. GBM exhibits intra- and inter-tumor heterogeneity, leading to drug resistance and eventual tumor recurrence. Conventional treatments for GBM include maximum surgical resection of glioma tissue, temozolomide administration, and radiotherapy, but these methods do not effectively halt cancer progression. Therefore, development of novel methods for the treatment of GBM and identification of new therapeutic targets are urgently required. In recent years, studies have shown that drugs related to mitophagy and mitochondrial apoptosis pathways can promote the death of glioblastoma cells by inducing mitochondrial damage, impairing adenosine triphosphate (ATP) synthesis, and depleting large amounts of ATP. Some studies have also shown that modern nano-drug delivery technology targeting mitochondria can achieve better drug release and deeper tissue penetration, suggesting that mitochondria could be a new target for intervention and therapy. The combination of drugs targeting mitochondrial apoptosis and autophagy pathways with nanotechnology is a promising novel approach for treating GBM.This article reviews the current status of drug therapy for GBM, drugs targeting mitophagy and mitochondrial apoptosis pathways, the potential of mitochondria as a new target for GBM treatment, the latest developments pertaining to GBM treatment, and promising directions for future research.

Sinomenium acutum: A Comprehensive Review of its Botany, Phytochemistry, Pharmacology and Clinical Application

Sinomenium acutumis the dry stem of Sinomenium acutum (Thunb.) Rehd et Wils. (S. acutum) and Sinomenium acutum(Thunb.) Rehd. et Wils. var. cinereumRehd. et Wils and is mainly distributed in China and Japan. As a traditional Chinese medicine (TCM) for dispelling wind and dampness in China, it is widely distributed and has a long history of drug use. In recent years, with the increase of the incidence of rheumatoid disease, S. acutum has become the focus of research. This paper reviews the literature on the chemical constituents, pharmacological effects, clinical applications and pharmacokinetics and safety of S. acutum from the past 60 years. At present, more than 210 natural compounds have been isolated from S. acutum, including alkaloids, lignans, triterpenoid saponins, steroids, and other structures. Pharmacological activities of S. acutum were mainly reported on anti-inflammatory, analgesic, anti-allergic, immunosuppressive, anti-tumor, liver-protective, anti-oxidative, and other effects, and clinical applications were mainly recorded on rheumatoid arthritis, ankylosing spondylitis, and other diseases. The clinical use of SIN has fewer side effects and more safety; only a small number of gastrointestinal reactions occurred, and the symptoms disappeared after the drug stopped. The purpose of this paper is to lay a foundation and provide reference for the follow-up research and wide application of S. acutum.

Synthesis, Antitumor of Sinomenine Derivatives and Apoptotic Induction via IL-6/PI3K/Akt/NF-κB Signaling Pathway in MCF-7 Cells

Natural products have been widely considered as an important resource for new drugs or lead compounds. Sinomenine (SIN) and its derivatives exert antitumor activity via regulation of inflammatory mediators. For these reasons we synthesized three series of SIN derivatives (compounds 4a-i, 7a-c and 11a-c) as antitumor agents from this natural product. All compounds were prepared by the modification at the C1 and C4 positions of A ring, the C4 position of A ring and the C6 and C7 positions of C ring, respectively. All the derivatives were subjected to in vitro antitumor activity against HeLa, A549, HepG-2, MCF-7 and HT-29 cell lines. To observe the apoptotic induction of SIN derivatives and its mechanism, fluorescent staining and western bolt were carried out for active compound against MCF-7. Based on the screening results, most of SIN derivatives showed better antitumor activity than SIN. Some of them were found to possess broad spectrum antitumor activity. Most notably, 11c exhibited obvious antitumor activity in both cell lines with IC50 value less than 11 μM. Besides, 11c induced apoptosis of MCF-7 in a dose-dependent manner. Western blot assay demonstrated that 11c inhibited IL-6-mediated activation of PI3K/Akt pathway. A docking study revealed that 11c had stronger binding interaction with the residues of IL-6 than SIN. All these results indicate that 11c may be a potential anti-breast cancer agent by directly targeting IL-6.

PI3K/AKT/p53 pathway inhibits infectious spleen and kidney necrosis virus infection by regulating autophagy and immune responses

The PI3K/AKT/p53 signaling pathway is activated by various types of cellular stimuli or pathogenic infection, and then regulates fundamental cellular functions to combat these stimulations. Here, we studied the meaningful roles of PI3K/AKT/p53 in regulating cellular machine such as autophagy, immune responses, as well as antiviral activity in Chinese perch brain (CPB) cells infected by infectious spleen and kidney necrosis virus (ISKNV), which is an agent caused devastating losses in mandarin fish (Siniperca chuatsi) industry. We found that ISKNV infection induced up-regulation of host PI3K/AKT/p53 axis, but inhibited autophagy in CPB cells. Interestingly, activation of PI3K/AKT/p53 axis factors trough agonists or overexpression dramatically decreased host autophagy level, inhibited ISKNV replication, and elevated the expression of immune-related genes in CPB cells. In contrast, suppression of PI3K/AKT/p53 pathway by inhibitors or small interfering RNA (siRNA)-mediated gene silence increased the autophagy and ISKNV replication, but down-regulated immune responses in CPB cells. All these results indicate that PI3K/AKT/p53 pathway plays an important role in anti-ISKNV infection and can be used as a new target for controlling ISKNV disease.

Sinomenine ester derivative inhibits glioblastoma by inducing mitochondria-dependent apoptosis and autophagy by PI3K/AKT/mTOR and AMPK/mTOR pathway

Glioblastoma multiforme (GBM) in the central nervous system is the most lethal advanced glioma and currently there is no effective treatment for it. Studies of sinomenine, an alkaloid from the Chinese medicinal plant, Sinomenium acutum, showed that it had inhibitory effects on several kinds of cancer. Here, we synthesized a sinomenine derivative, sino-wcj-33 (SW33), tested it for antitumor activity on GBM and explored the underlying mechanism. SW33 significantly inhibited proliferation and colony formation of GBM and reduced migration and invasion of U87 and U251 cells. It also arrested the cell cycle at G2/M phase and induced mitochondria-dependent apoptosis. Differential gene enrichment analysis and pathway validation showed that SW33 exerted anti-GBM effects by regulating PI3K/AKT and AMPK signaling pathways and significantly suppressed tumorigenicity with no obvious adverse effects on the body. SW33 also induced autophagy through the PI3K/AKT/mTOR and AMPK/mTOR pathways. Thus, SW33 appears to be a promising drug for treating GBM effectively and safely.

p75NTR silencing inhibits proliferation, migration, and extracellular matrix deposition of hypertrophic scar fibroblasts by activating autophagy through inhibiting the PI3K/Akt/mTOR pathway

Hypertrophic scar (HS) results from abnormal wound healing, accompanied by excessive hypercellularity, migration, and extracellular matrix (ECM) deposition. Autophagy dysregulation plays crucial roles during HS formation. The overexpressed p75 neurotrophin receptor (p75NTR) in injured skin tissue after wound healing becomes a factor aggravating scar. This study was designed to investigate the role of p75NTR and p75NTR-mediated autophagy in the process of HS. The results revealed that p75NTR expression was significantly upregulated while that of autophagy proteins was downregulated in cicatrix at 3 and 6 months after a burn, which was recovered at 12 months. p75NTR silencing inhibited proliferation, migration, and ECM deposition of hypertrophic scar fibroblasts (HSF), whereas p75NTR overexpression presented the opposite results. Silencing of p75NTR reduced the expression of PI3K/Akt/mTOR signaling molecules while enhancing that of autophagy proteins. Importantly, PI3K agonist (IGF-1) intervention notably decreased the levels of LC3B II/I and Beclin-1 and restored the inhibitory effects of p75NTR silencing on proliferation, migration, and ECM deposition of HSF. Concurrently, autophagy inhibitor 3-methyladenine (3-MA) treatment exhibited the same variation trends with IGF-1. Taken together, these findings demonstrated that p75NTR silencing inhibits proliferation, migration, and ECM deposition of HSF by activating autophagy by inhibiting the PI3K/Akt/mTOR pathway.

Compound TDB (Tricyclic decyl benzoxazole) induces autophagy-dependent apoptosis in the gastric cancer cell line MGC-803 by regulating PI3K/AKT/mTOR

OBJECTIVE

Gastric cancer is a potential malignant tumor. Extensive research has shown that apoptosis and autophagy are important mechanisms of cancer pathogenesis. This study aimed to explore the role and mechanism of TDB in apoptosis and autophagy in MGC-803 cells.

METHODS

In cell experiments, the proliferation, apoptosis and autophagy of MGC-803 cells were evaluated by the MTT assay, TUNEL, flow cytometry, MDC, and TEM. Through molecular experiments, the TDB-induced apoptosis and autophagy effects were evaluated by examining the levels of Cleaved-PARP/PARP, Cleaved-caspase3/procaspase3, Beclin-1, p62 and the ratio of LC3-II/LC3-I. At the animal level, the anti-tumor effect of TDB in vivo was evaluated by assessing tumor volume and bioluminescence value.

RESULTS

Regarding mechanism, TDB induces apoptosis and autophagy through PI3K/AKT/mTOR. At the same time, more importantly, TDB promotes 3-methyladenine or autophagy activator rapamycin-mediated. The induced proliferation inhibition and pro-apoptosis effect, which inhibit autophagy and induce an increase in apoptosis.

CONCLUSION

TDB may up-regulate PARP, Cleaved Caspase-3, Beclin1 and LC3B and down-regulate the expression of P62 and other apoptosis and autophagy genes through the activation of PI3K/AKT/mTOR pathway signalling proteins, leading to autophagy-dependent apoptosis. At the animal level, TDB has good anti-tumor efficacy in vivo. In summary, TDB has potential anti-tumor efficacy in vivo and in vitro.

Alternative Options for Skin Cancer Therapy via Regulation of AKT and Related Signaling Pathways

Global environmental pollution has led to human exposure to ultraviolet (UV) radiation due to the damaged ozone layer, thereby increasing the incidence and death rate of skin cancer including both melanoma and non-melanoma. Overexpression and activation of V-akt murine thymoma viral oncogene homolog (AKT, also known as protein kinase B) and related signaling pathways are major factors contributing to many cancers including lung cancer, esophageal squamous cell carcinoma and skin cancer. Although BRAF inhibitors are used to treat melanoma, further options are needed due to treatment resistance and poor efficacy. Depletion of AKT expression and activation, and related signaling cascades by its inhibitors, decreases the growth of skin cancer and metastasis. Here we have focused the effects of AKT and related signaling (PI3K/AKT/mTOR) pathways by regulators derived from plants and suggest the need for efficient treatment in skin cancer therapy.

Polyphyllin I Promoted Melanoma Cells Autophagy and Apoptosis via PI3K/Akt/mTOR Signaling Pathway

To investigate whether Polyphyllin I (PPI) might induce the autophagy and apoptosis of melanoma cells by regulating PI3K/Akt/mTOR signal pathway. Melanoma A375 cells were incubated with different concentrations of Polyphyllin I (0, 1.5, 3.0, and 6.0 mg/L) and PI3K/Akt/mTOR signaling pathway activator IGF-1(20 mg/L). CCK-8 assay was utilized to detect cell proliferation; Cell apoptosis and cell cycle were measured by flow cytometry; Western blot was used to examine the expressions of proteins. Immunofluorescence analysis was performed to evaluate autophagy of A375 cells; In addition, xenograft-bearing nude mice were applied to study the role of Polyphyllin I on melanoma development, melanoma cell proliferation, as well as melanoma cell apoptosis in vivo. The outcomes represented that Polyphyllin I promoted A375 cell apoptosis via upregulating Bax level and cleaved caspase-3 level and downregulating Bcl-2 level, inhibited the growth of A375 cells at the G0/G1 phase, and enhanced cell autophagy via regulating the levels of Beclin 1, LC3II, and p62. However, IGF-1 (an activator of PI3K/Akt/mTOR signal pathway) attenuated these changes that Polyphyllin I induced. Furthermore, the xenograft model experiment confirmed that Polyphyllin I treatment suppressed xenograft tumor growth, increased apoptotic index evaluated by the TUNEL method, and reduced the level of Ki67 in tumor tissues in vivo. In conclusion, Polyphyllin I treatment enhanced melanoma cell autophagy and apoptosis, as well as blocked melanoma cell cycle via suppressing PI3K/Akt/mTOR signal pathway. Meanwhile, Polyphyllin I treatment suppressed the development of melanoma in vivo. Therefore, Polyphyllin I possibly is a promising molecular targeted agent used in melanoma therapy.

Ezetimibe protects against spinal cord injury by regulating autophagy and apoptosis through inactivation of PI3K/AKT/mTOR signaling

Spinal cord injury (SCI) is a severe traumatic disease of the central nervous system characterized by high incidence and disability rate. We aimed to investigate the therapeutic potential of Ezetimibe (Eze) in SCI and identify the underlying mechanisms. Acute SCI rat model was established by using the modified weight-drop method. Following administration with Eze, the neurological function was evaluated using the Basso, Beattie, and Bresnahan (BBB) locomotor scale score, and the motor neurons were stained with Nissl staining. The pathological changes of spinal cord tissues were tested using Hematoxylin and eosin staining. The presence of apoptotic cells was examined using Terminal dexynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining. Moreover, the expression of main autophagy markers LC3II/I, Beclin1 and p62 and apoptosis-related proteins was tested using western blot analysis. The changes of PI3K/AKT/mTOR signaling-associated proteins were measured. Experimental results showed that Eze treatment obviously improved functional recovery, the neuronal survival and morphological characteristics of spinal cord. Additionally, Eze administration dramatically upregulated the expression of LC3II/I and Beclin1 whereas downregulated that of p62. Concurrently, significantly reduced apoptosis was observed following Eze intervention, accompanied by increased expression of anti-apoptotic protein Bcl-2 and decreased expression of pro-apoptotic proteins Bax, cleaved caspase-3 and cleaved caspase-9. Further results indicated that Eze treatment remarkably suppressed the expression of phospho-PI3K (p-PI3K), p-AKT and p-mTOR. These findings demonstrated that Eze could protect against SCI by activating autophagy and hindering apoptosis through regulating PI3K/AKT/mTOR signaling, suggesting a potential candidate for SCI therapy.

Sinomenine Inhibits Non-Small Cell Lung Cancer via Downregulation of Hexokinases II-Mediated Aerobic Glycolysis

Background

Addiction to aerobic glycolysis is a common metabolic phenotype in human non-small cell lung cancer (NSCLC). The natural product Sinomenine (Sin) exhibits significant anti-tumor effects in various human cancers. However, the underlying mechanism remains elusive.

Methods

The inhibitory effect of Sin on NSCLC cells was determined by MTS and soft agar assays. The glycolysis efficacy of NSCLC cells was examined by glucose uptake and lactate production. The activation of Akt signaling and the protein level of hexokinases II (HK2) were examined by immunoblot (IB), qRT-PCR, and immunohistochemical staining (IHC). The in vivo anti-tumor effect of Sin was validated by the xenograft mouse model.

Results

We showed that HK2 is highly expressed in NSCLC tissues and cell lines. Depletion of HK2 suppressed cell viability, anchorage-independent colony formation, and xenograft tumor growth. Sinomenine exhibited a profound inhibitory effect on NSCLC cells by reducing HK2-mediated glycolysis both in vitro and in vivo. Ectopic overexpression of HK2 compromised these anti-tumor efficacies in sinomenine-treated NSCLC cells. Moreover, we revealed that sinomenine decreased Akt activity, which caused the down-regulation of HK2-mediated glycolysis. Knockdown of Akt reduced HK2 protein level and impaired glycolysis. In contrast, overexpression of constitutively activated Akt1 reversed this phenotype.

Conclusion

This study suggests that targeting HK2-mediated aerobic glycolysis is required for sinomenine-mediated anti-tumor activity.

MTH1 Inhibitor TH287 Suppresses Gastric Cancer Development Through the Regulation of PI3K/AKT Signaling

Background: Cancer cells evade oxidative stress through the MutT homologue-1 (MTH1), a member of the Nudix family. MTH1 maintains genome integrity and the viability of tumor cells. A new class of MTH1 inhibitors have attracted interest as anticancer agents, but their mechanisms of action remain poorly characterized. In this study, the authors evaluated the anticancer effects of the MTH1 inhibitor TH287 on gastric cancer (GCa) cells. Materials and Methods: BGC-823 and SGC-7901 cells were treated with TH287 and CCK-8, and colony-forming assays were performed. Cell migration was assessed through Transwell and scratch assays. Apoptotic status was measured via flow cytometry and 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolyl-carbocyanine iodide (JC-1) staining. Cell cycle status was assessed by propidium iodide (PI) staining. The expression of PI3K/AKT signaling-related proteins was verified by western blotting. Results: TH287 inhibited cell viability, reduced cell proliferation, inhibited apoptosis, induced G2/M arrest, and suppressed cell migration. A loss of mitochondrial membrane potential and reduced Bcl-2/Bax expression were also observed in TH287-treated cells. These effects were mediated through the inhibition of pro-oncogenic PI3K/AKT signaling. Conclusions: These findings indicate that the MTH1 inhibitor TH287 mediates an array of anticancer effects in GCa cells through its effects on mitochondrial function and PI3K/AKT signaling. Collectively, these data highlight the promise of TH287 as a novel therapeutic option for GCa cells.

Repurposing of plant alkaloids for cancer therapy: Pharmacology and toxicology

Drug repurposing (or repositioning) is an emerging concept to use old drugs for new treatment indications. Phytochemicals isolated from medicinal plants have been largely neglected in this context, although their pharmacological activities have been well investigated in the past, and they may have considerable potentials for repositioning. A grand number of plant alkaloids inhibit syngeneic or xenograft tumor growth in vivo. Molecular modes of action in cancer cells include induction of cell cycle arrest, intrinsic and extrinsic apoptosis, autophagy, inhibition of angiogenesis and glycolysis, stress and anti-inflammatory responses, regulation of immune functions, cellular differentiation, and inhibition of invasion and metastasis. Numerous underlying signaling processes are affected by plant alkaloids. Furthermore, plant alkaloids suppress carcinogenesis, indicating chemopreventive properties. Some plant alkaloids reveal toxicities such as hepato-, nephro- or genotoxicity, which disqualifies them for repositioning purposes. Others even protect from hepatotoxicity or cardiotoxicity of xenobiotics and established anticancer drugs. The present survey of the published literature clearly demonstrates that plant alkaloids have the potential for repositioning in cancer therapy. Exploitation of the chemical diversity of natural alkaloids may enrich the candidate pool of compounds for cancer chemotherapy and -prevention. Their further preclinical and clinical development should follow the same stringent rules as for any other synthetic drug as well. Prospective randomized, placebo-controlled clinical phase I and II trials should be initiated to unravel the full potential of plant alkaloids for drug repositioning.

Targeting PI3K/AKT/mTOR-mediated autophagy for tumor therapy

Autophagy is a highly conserved catabolic process and participates in a variety of cellular biological activities. The phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway, as a critical regulator of autophagy, is involved in the initiation and promotion of a series of pathological disorders including various tumors. Autophagy also participates in regulating the balance between the tumor and the tumor microenvironment. Natural products have been considered a treasure of new drug discoveries and are of great value to medicine. Mounting evidence has suggested that numerous natural products are targeting PI3K/AKT/mTOR-mediated autophagy, thereby suppressing tumor growth. Furthermore, autophagy plays a "double-edged sword" role in different tumors. Targeting PI3K/AKT/mTOR-mediated autophagy is an important therapeutic strategy for a variety of tumors, and plays important roles in enhancing the chemosensitivity of tumor cells and avoiding drug resistance. Therefore, we summarized the roles of PI3K/AKT/mTOR-mediated autophagy in tumorigenesis, progression, and drug resistance of tumors, which may be utilized to design preferably therapeutic strategies for various tumors.

Modulation of Multiple Signaling Pathways of the Plant-Derived Natural Products in Cancer

Natural compounds are highly effective anticancer chemotherapeutic agents, and the targets of plant-derived anticancer agents have been widely reported. In this review, we focus on the main signaling pathways of apoptosis, proliferation, invasion, and metastasis that are regulated by polyphenols, alkaloids, saponins, and polysaccharides. Alkaloids primarily affect apoptosis-related pathways, while polysaccharides primarily target pathways related to proliferation, invasion, and metastasis. Other compounds, such as flavonoids and saponins, affect all of these aspects. The association between compound structures and signaling pathways may play a critical role in drug discovery.

Sinomenine ameliorates intervertebral disc degeneration via inhibition of apoptosis and autophagy in vitro and in vivo

BACKGROUND

Aberrant apoptosis in nucleus pulposus (NP) cells is the primary cause of intervertebral disc degeneration (IDD). In contrast, a large number of studies have confirmed that autophagy may protect NP cells from apoptosis. Sinomenine is an alkaloid monomer, which has been reported to stimulate cell autophagy. Therefore, the aim of the present study was to investigate the effects of sinomenine on IDD.

METHODS

The effects of sinomenine on the proliferation and apoptosis of NP cells were evaluated with the CCK-8 assay and Annexin V/PI staining, respectively.

RESULTS

The data obtained from the present study demonstrated that sinomenine could notably reverse TBHP-induced growth inhibition and apoptosis in rat NP cells. In addition, sinomenine significantly induced autophagy in rat NP cells, which was completely inhibited by 3-methyladenine (3MA). In addition, the protective effect of sinomenine against TBHP in rat NP cells was abolished following treatment with 3MA. Finally, an in vivo study further confirmed that sinomenine could ameliorate rat IDD.

CONCLUSION

Taken together, the results of the present study indicated sinomenine could ameliorate rat IDD via induction of autophagy in vitro and in vivo. These findings suggest the therapeutic potential of sinomenine in the prevention of IDD.

Clinical outcomes of BRAF plus MEK inhibition in melanoma: A meta-analysis and systematic review

Background

Melanoma is a potentially fatal malignancy with poor prognosis. Several recent studies have demonstrated that combination therapy of BRAF and MEK inhibition achieved better curative effect and appeared less toxic effects. We conducted a meta‐analysis to evaluate the efficacy and safety between BRAF inhibition plus MEK inhibition combination therapy and BRAF inhibition monotherapy in melanoma patients.

Methods

We performed the search in PubMed, EMBASE, and the Cochrane Library from January 2010 to January 2019. Inclusion and exclusion of studies, assessment of quality, outcome measures, data extraction, and synthesis were independently accomplished by two reviewers. Revman 5.3 software was used for the meta‐analysis.

Results

Totally, seven randomized controlled trials involving 3146 patients met our inclusion criteria. Comparing the results of combination therapy and monotherapy, combination therapy significantly improved OS (RR = 1.13; 95% CI, 1.08, 1.19; P < 0.00001), ORR (RR = 1.36; 95% CI, 1.28, 1.45; P < 0.00001), PFS (RR = 0.57; 95% CI, 0.52, 0.63; P < 0.00001) and reduced deaths (RR = 0.78; 95% CI, 0.69, 0.88; P < 0.0001). Skin‐related adverse events such as hyperkeratosis, cutaneous squamous‐cell carcinoma were less compared with monotherapy. However, gastrointestinal events like nausea, diarrhea, and vomiting were at a higher frequency.

Conclusion

Doublet BRAF and MEK inhibition achieved better survival outcomes over single‐agent BRAF inhibition and occurred less skin‐related events, but gastrointestinal events were more in combination therapy.

Role and Therapeutic Targeting of the PI3K/Akt/mTOR Signaling Pathway in Skin Cancer: A Review of Current Status and Future Trends on Natural and Synthetic Agents Therapy

The mammalian or mechanistic target of rapamycin (mTOR) and associated phosphatidyl-inositiol 3-kinase (PI3K)/protein kinase B (Akt) pathways regulate cell growth, differentiation, migration, and survival, as well as angiogenesis and metabolism. Dysregulation of these pathways is frequently associated with genetic/epigenetic alterations and predicts poor treatment outcomes in a variety of human cancers including cutaneous malignancies like melanoma and non-melanoma skin cancers. Recently, the enhanced understanding of the molecular and genetic basis of skin dysfunction in patients with skin cancers has provided a strong basis for the development of novel therapeutic strategies for these obdurate groups of skin cancers. This review summarizes recent advances in the roles of PI3K/Akt/mTOR and their targets in the development and progression of a broad spectrum of cutaneous cancers and discusses the current progress in preclinical and clinical studies for the development of PI3K/Akt/mTOR targeted therapies with nutraceuticals and synthetic small molecule inhibitors.

Sinomenine exerts antitumour effect in gastric cancer cells via enhancement of miR-204 expression

Gastric carcinoma (GC) is a pernicious neoplasm with high morbidity and mortality. Sinomenine (SIN) has long been exploited to heal rheumatoid arthritis. Recently, SIN has been discovered to exert the antitumour functions in diverse cancers. However, the impacts of SIN on GC remain indistinct. We attempted to expose the antitumour effect of SIN on GC. MKN45 and SGC-7901 cells were administered with SIN for 24 hours, cell viability, proliferation, apoptosis, migration, invasion and the associated proteins in the above processes were examined via exploiting CCK-8, BrdU, flow cytometry, Transwell and Western blot. MiR-204 expression in GC tumour tissues, different GC cell lines and SIN-stimulated GC cells was investigated by executing RT-qPCR. The above cell biological processes were reassessed after transfection with miR-204 inhibitor. The latent mechanisms were probed by examining AMPK and Wnt/β-catenin pathways. We found that SIN memorably repressed cell proliferation, evoked apoptosis and affected CyclinD1, Bcl-2, Bax and cleaved-caspase-3 expression in MKN45 and SGC-7901 cells. Cell migration, invasion and expression of MMP-9 and Vimentin were all restrained by SIN stimulation. The increase of miR-204 was discovered in GC tissues and SIN-treated MKN45 and SGC-7901 cells. But suppression of miR-204 was observed in AGS, MKN28, MKN45 and SGC-7901 cells. Suppression of miR-204 overturned the inhibitory functions of SIN in MKN45 and SGC-7901 cells. Besides, SIN prohibited AMPK and Wnt/β-catenin pathways via enhancement of miR-204. In conclusion, these findings suggested that SIN exerted the antitumour activity in GC cells by hindering AMPK and Wnt/β-catenin pathways via enhancement of miR-204.