Ameliorative effects of Modified Huangqi Chifeng decoction on podocyte injury via autophagy mediated by PI3K/AKT/mTOR and AMPK/mTOR pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Proteinuria is recognized as a risk factor for the exacerbation of chronic kidney disease. Modified Huangqi Chifeng decoction (MHCD) has distinct advantages in reducing proteinuria. Our previous experimental results have shown that MHCD can inhibit excessive autophagy. However, the specific mechanism by which MHCD regulates autophagy needs to be further explored.

AIM OF THE STUDY

In this study, in vivo and in vitro experiments were conducted to further clarify the protective mechanism of MHCD on the kidney and podocytes by regulating autophagy based on phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) and adenosine monophosphate-activated protein kinase (AMPK)/mTOR signaling pathways.

MATERIALS AND METHODS

By a single injection via the tail vein, Sprague-Dawley rats received Adriamycin (5 mg/kg) to establish a model of proteinuria nephropathy. They were divided into control, model, MHCD, 3-methyladenine (3 MA), 3 MA + MHCD, and telmisartan groups and were administered continuously for 6 weeks. The MHCD-containing serum was prepared, and a model of podocyte injury induced by Adriamycin (0.2 μg/mL) was established.

RESULTS

MHCD reduced the 24-h urine protein levels and relieved pathological kidney damage. During autophagy in the kidneys of rats with Adriamycin-induced nephropathy, the PI3K/AKT/mTOR signaling pathway is inhibited, while the AMPK/mTOR signaling pathway is activated. MHCD antagonized these effects, thereby inhibiting excessive autophagy. MHCD alleviated Adriamycin-induced podocyte autophagy, as demonstrated using Pik3r1 siRNA and an overexpression plasmid for Prkaa1/Prkaa2. Furthermore, MHCD could activate the PI3K/AKT/mTOR signaling pathway while suppressing the AMPK/mTOR signaling pathway.

CONCLUSIONS

This study demonstrated that MHCD can activate the interaction between the PI3K/AKT/mTOR and the AMPK/mTOR signaling pathways to maintain autophagy balance, inhibit excessive autophagy, and play a role in protecting the kidneys and podocytes.

Bufalin targeting BFAR inhibits the occurrence and metastasis of gastric cancer through PI3K/AKT/mTOR signal pathway

Gastric cancer (GC) is the most common malignant tumor of digestive system. Bufalin extracted from Venenum Bufonis is one of the most effective anticancer monomers, which has been proved to play anticancer roles in a variety of cancers such as ovarian cancer, prostate cancer and neuroblastoma. However, there are few studies on bufalin in GC, and lack of clear targets. The effect of bufalin on the proliferation and migration of GC cells was detected by CCK-8, scratch wound healing assay, transwell assay and Western blotting. The potential direct interaction proteins of bufalin were screened by human proteome microarray containing 21,838 human proteins. The target protein was determined by bioinformatics, and the binding sites were predicted by molecular docking technique. Biological experiments in vitro and in vivo were conducted to verify the effect of bufalin directly interaction protein and the mechanism of bufalin targeting the protein to inhibit the development of GC. The results showed that bufalin inhibited the proliferation and migration of MKN-45 and HGC-27 GC cell lines in vitro. BFAR, a direct interaction protein of bufalin has several potential binding sites to bufalin. BFAR is highly expressed in GC and promotes the occurrence and metastasis of GC by activating PI3K/AKT/mTOR signal pathway in vitro and in vivo. Bufalin reversed the promoting effect of BFAR on the carcinogenesis and metastasis of GC by down-regulating the expression of BFAR. Our results show that bufalin targeting BFAR inhibits the occurrence and metastasis of GC through PI3K/AKT/mTOR signal pathway. These results provide a new basis for bufalin as a promising drug for the treatment of GC.

Hinokiflavone Inhibits Growth of Esophageal Squamous Cancer By Inducing Apoptosis via Regulation of the PI3K/AKT/mTOR Signaling Pathway

Background

Globally, esophageal cancer ranks as the seventh most common cancer. Esophageal squamous cell carcinoma (ESCC) is one of its major histological types. ESCC accounts for the vast majority of cases in China, and the mortality rate is high. Cisplatin, the standard adjuvant chemotherapy drug for ESCC, has a modest response rate due to the development of drug resistance. Hinokiflavone (HF) is a natural biflavonoid compound with anti-melanoma activity. However, its anti-tumor effect on ESCC and the underlying mechanisms remain largely unknown.

Methods

The ESCC cell lines KYSE150 and TE14 were used. The cell counting kit-8 assay and flow cytometry analysis, along with colony formation, EdU, wound healing, and Transwell migration assays, were performed to assess cell characteristics (viability, migration, invasion, and apoptosis) following treatment with HF. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), western blotting, and molecular docking were used to investigate the pathways potentially modulated by HF. In vivo anti-tumor effects of HF were also investigated using a mouse xenograft model.

Results

Our findings revealed that HF inhibited ESCC cell proliferation. Hoechst 33342 staining, annexin V-FITC/PI staining, and western blotting confirmed that HF causes caspase-dependent apoptosis. KEGG pathway enrichment analysis and western blotting indicated that the PI3K/AKT/mTOR pathway played an important role in the process of HF-induced apoptosis. Furthermore, HF effectively impaired the migration and invasion abilities of KYSE150 cells and downregulated the expression of the matrix metalloproteinases (MMP) MMP2 and MMP9. HF inhibited tumor growth and exhibited minimal toxicity in the organs of the KYSE150 xenograft model.

Conclusion

This is the first study to demonstrate the inhibition of ESCC growth and progression by HF. The underlying mechanism is through blocking the PI3K/AKT/mTOR signaling pathway, thereby inhibiting cell proliferation and inducing apoptosis. HF can be used as a complementary/alternative agent for ESCC therapy.

Rosmarinic acid inhibits proliferation and invasion of hepatocellular carcinoma cells SMMC 7721 via PI3K/AKT/mTOR signal pathway

OBJECTIVE

To investigate the effect of rosmarinic acid (RosA) on hepatocellular carcinoma cell in vivo and in vitro and to explore its possible mechanism of anti-hepatocarcinoma.

METHODS

The hepatocellular carcinoma cell line SMMC-7721 was treated with different concentrations of RosA (0, 20, 50, 100 μmol/L) to detect cell proliferation, cell cycle, apoptosis and invasion.PI3K pathway-specific activator IGF-1 was used to explore whether the mechanism for RosA action relates to PI3K/AKT signal pathway.Nude mice inoculated with SMMC-7721 cells were treated with different doses of RosA (0, 5, 10 and 20 mg/kg) to detect the tumor formation of cancer cells in vivo.

RESULTS

RosA significantly inhibited the proliferation of SMMC-7721 cells and induced G1 arrest and apoptosis in a dose-dependent manner. RosA might inhibit cell invasion by regulating epithelial-mesenchymal transition. Rescue experiments showed that IGF-1 could reverse the inhibition of PI3K/AKT/mTOR signal pathway by RosA and the effect on proliferation, apoptosis, cell cycle, invasion and EMT by IGF-1 in SMMC-7721 cells;RosA could inhibit tumor formation of SMMC-7721 cells in vivo.

CONCLUSION

RosA can inhibit the proliferation and invasion of hepatocellular carcinoma cell in vitro and inhibit tumour growth in vivo and the mechanism may relate to inhibiting the activation of PI3K/AKT signal pathway.

[Inhibitory effect and mechanism of platycodin D combined with imatinib on K562/R]

Platycodin D(PD) has a significantly inhibitory effect on multiple malignant tumors, and can inhibit the proliferation of leukemia cells K562 and induce apoptosis. However, its effect in improving the sensitivity of drug-resistant cells to imatinib and their molecular mechanism remained unclear. To investigate the effect and mechanism of PD alone or combined with imatinib (IM) in inhibiting CML imatinib resistant cell line K562/R, the cell proliferation was examined by CCK8 assay to reveal the effect of PD on the inhibitory function of imatinib. Cell apoptosis was detected by Annexin V-FITC/PI double staining. Protein expressions of cleaved caspase-3, cleaved caspase-9, PARP, cleaved PARP, Bcr/abl, p-AKT and p-mTOR were detected by Western blot. The results showed that the inhibitory effect of PD combined with imatinib on the proliferation and apoptosis of K562/R cells was significantly higher than that of the control group and the single drug group. Protein expressions of cleaved caspase-3, cleaved caspase-9 and cleaved PARP were significantly up-regulated in the combination group, and protein expressions of PARP, Bcr/abl, p-AKT and p-mTOR were down-regulated. The results indicated that PD increased the sensitivity of drug-resistant cells to imatinib, and the inhibitory effect of PD combined with imatinib was significantly better than the single drug on cell proliferation, induction of apoptosis, inhibition of Bcr/abl protein and PI3K/AKT/mTOR signaling pathway.

MicroRNA-210 Protects PC-12 Cells Against Hypoxia-Induced Injury by Targeting BNIP3

MicroRNA (miR)-210 is the most consistently and predominantly up-regulated miR in response to hypoxia in multiple cancer cells. The roles of miR-210 in rat adrenal gland pheochromocytoma (PC-12) cells remain unknown. We aimed to explore the possible effect of miR-210 in neonatal brain injury. We explored the potential molecular mechanism by using PC-12 cells under hypoxia. Scramble miRs, miR-210 mimic, miR-210 inhibitor or its negative control were respectively transfected into PC-12 cells. Cell viability, migration, invasion and apoptosis were also assessed to evaluate hypoxia-induced cell injury. The expression level of miR-210 was identified by quantitative real-time polymerase chain reaction (qRT-PCR) analysis. Apoptosis-related protein expression as well as key kinases in the phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signal pathway was studied by Western blot analysis. Hypoxia suppressed cell viability, migration and invasion, but promoted apoptosis through activation of mitochondrial- and caspase-dependent pathways. Hypoxia markedly induced up-regulation of miR-210 in PC-12 cells. Overexpression of miR-210 protected PC-12 cells against hypoxia-induced injury. Bcl-2 adenovirus E1B 19 kDa-interacting protein 3 (BNIP3) was proven to be a target gene of miR-210 in PC-12 cells. miR-210 overexpression ameliorated the hypoxia-induced injury in PC-12 cells by down-regulating BNIP3. Hypoxia-induced alterations of key kinases in the PI3K/AKT/mTOR signal pathway were affected by aberrant expression of BNIP3. These findings suggested that miR-210 protected PC-12 cells against hypoxia-induced injury by targeting BNIP3, involving the PI3K/AKT/mTOR signal pathway.

PI3K/AKT/mTOR signaling pathway inhibitors in proliferation of retinal pigment epithelial cells

AIM

To determine whether the PI3K/AKT/mTOR pathway is activated in proliferative vitreoretinopathy (PVR) in homo-sapiens.

METHODS

The retina of controls and patients with PVR were collected and their levels of PI3K, phospho-AKT, phospho-mTOR, phospho-p70S6k and phospho-4EBP-1 were determined by Western blot. The cultured human retinal pigment epithelial cell line D407 was treated with a specific mTOR inhibitor, rapamycin (RAPA) or a PI3K inhibitor, LY294002, of various concentrations and durations. Cell morphology was observed by phase contrast microscopy and the proliferation and apoptosis of treated cells were determined by MTT assay and flow cytometry.

RESULTS

Levels of PI3K, phospho-AKT, phospho-mTOR, phospho-P70S6K and phospho-4EBP1 was increased in the retina in PVR (P<0.05). In D407 cells, both RAPA and LY294002 significantly inhibited cell proliferation and cell cycle progression, and promoted apoptosis (P <0.05); morphologically, the cells became smaller. Both RAPA and LY294002 reduced levels of phospho-AKT, phospho-mTOR, phospho-p70S6k and phospho-4EBP1 expression (P <0.05). RAPA, but not LY294002, had no significant effect on PI3K expression.

CONCLUSION

PI3K/AKT/mTOR signaling pathway is highly activated in the retinal pigment epithelial cells of PVR. The inhibitors of PI3K/AKT/mTOR signaling pathway, RAPA and LY294002, could inhibited the PI3K/AKT/mTOR signaling pathway by reducing the levels of phosphorylation of mTOR pathway components.