PTEN and rapamycin inhibiting the growth of K562 cells through regulating mTOR signaling pathway

Anti-hypertensive effect and potential mechanism of gastrodia-uncaria granules based on network pharmacology and experimental validation

Hypertension has become a major contributor to the morbidity and mortality of cardiovascular diseases worldwide. Despite the evidence of the anti-hypertensive effect of gastrodia-uncaria granules (GUG) in hypertensive patients, little is known about its potential therapeutic targets as well as the underlying mechanism. GUG components were sourced from TCMSP and HERB, with bioactive ingredients screened. Hypertension-related targets were gathered from DisGeNET, OMIM, GeneCards, CTD, and GEO. The STRING database constructed a protein-protein interaction network, visualized by Cytoscape 3.7.1. Core targets were analyzed via GO and KEGG using R package ClusterProfiler. Molecular docking with AutodockVina 1.2.2 revealed favorable binding affinities. In vivo studies on hypertensive mice and rats validated network pharmacology findings. GUG yielded 228 active ingredients and 1190 targets, intersecting with 373 hypertension-related genes. PPI network analysis identified five core genes: AKT1, TNF-α, GAPDH, IL-6, and ALB. Top enriched GO terms and KEGG pathways associated with the anti-hypertensive properties of GUG were documented. Molecular docking indicated stable binding of core components to targets. In vivo study showed that GUG could improve vascular relaxation, alleviate vascular remodeling, and lower blood pressure in hypertensive animal models possibly through inhibiting inflammatory factors such as AKT1, mTOR, and CCND1. Integrated network pharmacology and in vivo experiment showed that GUG may exert anti-hypertensive effects by inhibiting inflammation response, which provides some clues for understanding the effect and mechanisms of GUG in the treatment of hypertension.

LncRNA meg3 suppresses hepatocellular carcinoma in vitro and vivo studies

Although abnormal expression of the long non-coding RNA (lncRNA) MEG3 has been reported in multiple cancer types, the role of MEG3 in the pathobiology of hepatocellular carcinoma (HCC) remains unknown. This study evaluated the expression of lncRNA MEG3 and a microRNA (miRNA-10a-5p) implicated in HCC metastasis in cancer and carcinoma adjacent tissues of HCC samples (n=30 each) via in situ hybridization and quantitative RT-PCR. The effects of overexpressing either MEG3 alone, or MEG3 in combination with miRNA-10a-5p, on the proliferation, apoptosis, cell cycle progression, migration, and invasion of HepG2 cells were evaluated using functional assays. Dual luciferase reporter assays and western blotting were employed to delineate the mechanisms of MEG3 and miRNA-10a-5p regulation of key oncogenes and tumor suppressors in HCC cells. Compared to carcinoma-adjacent regions, MEG3 expression was downregulated in cancer regions of HCC samples; by contrast, miRNA-10a-5p was overexpressed in cancer regions compared to tumor-adjacent areas. Furthermore, overexpression of MEG3 (a) decreased proliferation, migration, and invasion of HepG2 cells; (b) enhanced apoptosis and the proportion of HepG2 cells in G1 of the cell cycle; (c) increased the expression of phosphatase and tensin homolog (PTEN), Bcl2-associated X (Bax), and p53 proteins; and (d) decreased the expression of miRNA-10a-5p, AKT, p-AKT, Bcl-2, and the matrix metalloproteinases (MMPs)-2 and -9. Furthermore, miRNA-10a-5p bound the 3-untranslated region of PTEN mRNA and downregulated PTEN protein expression. Taken together, these data suggest that MEG3 regulates the PTEN/AKT/MMP-2/MMP-9 signaling axis and contributes to HCC development by targeting miRNA-10a-5p.

The subsequent biological effects of simulated microgravity on endothelial cell growth in HUVECs

PURPOSE

Microgravity is known to cause endothelium dysfunction in astronauts returning from spaceflight. We aimed to reveal the regulatory mechanism in alterations of human endothelial cells after simulated microgravity (SMG).

METHODS

We utilized the rotary cell culture system (RCCS-1) to explore the subsequent effects of SMG on human umbilical vein endothelial cells (HUVECs).

RESULTS

SMG-treated HUVECs appeared obvious growth inhibition after return to normal gravity, which might be attributed to a set of responses including alteration of cytoskeleton, decreased cell adhesion capacity and increased apoptosis. Expression levels of mTOR and its downstream Apaf-1 were increased during subsequent culturing after SMG. miR-22 was up-regulated and its target genes SRF and LAMC1 were down-regulated at mRNA levels. LAMC1 siRNAs reduced cell adhesion rate and inhibited stress fiber formation while SRF siRNAs caused apoptosis.

CONCLUSION

SMG has the subsequent biological effects on HUVECs, resulting in growth inhibition through mTOR signaling and miR-22-mediated mechanism.

Phosphatase and tensin homologue: a therapeutic target for SMA

Spinal muscular atrophy (SMA) is one of the most common juvenile neurodegenerative diseases, which can be associated with child mortality. SMA is caused by a mutation of ubiquitously expressed gene, Survival Motor Neuron1 (SMN1), leading to reduced SMN protein and the motor neuron death. The disease is incurable and the only therapeutic strategy to follow is to improve the expression of SMN protein levels in motor neurons. Significant numbers of motor neurons in SMA mice and SMA cultures are caspase positive with condensed nuclei, suggesting that these cells are prone to a process of cell death called apoptosis. Searching for other potential molecules or signaling pathways that are neuroprotective for central nervous system (CNS) insults is essential for widening the scope of developmental medicine. PTEN, a Phosphatase and Tensin homologue, is a tumor suppressor, which is widely expressed in CNS. PTEN depletion activates anti-apoptotic factors and it is evident that the pathway plays an important protective role in many neurodegenerative disorders. It functions as a negative regulator of PIP3/AKT pathway and thereby modulates its downstream cellular functions through lipid phosphatase activity. Moreover, previous reports from our group demonstrated that, PTEN depletion using viral vector delivery system in SMN delta7 mice reduces disease pathology, with significant rescue on survival rate and the body weight of the SMA mice. Thus knockdown/depletion/mutation of PTEN and manipulation of PTEN medicated Akt/PKB signaling pathway may represent an important therapeutic strategy to promote motor neuron survival in SMA.

Pancreatic cancer cell-derived IGFBP-3 contributes to muscle wasting

Background

Progressive loss of skeletal muscle, termed muscle wasting, is a hallmark of cancer cachexia and contributes to weakness, reduced quality of life, as well as poor response to therapy. Previous studies have indicated that systemic host inflammatory response regarding tumor development results in muscle wasting. However, how tumor directly regulates muscle wasting via tumor-derived secreted proteins is still largely unknown.

Methods

In this study, we performed bioinformatics analysis in two datasets of pancreatic ductal adenocarcinoma, which causes cancer cachexia and muscle wasting with the highest prevalence, and uncovered that IGFBP3, which encodes IGF-binding protein-3 (IGFBP-3), is dramatically up-regulated in pancreatic tumor samples. We also verified the wasting effect of IGFBP-3 on C2C12 muscle cells with biochemical and genetic assays.

Results

IGFBP-3 potently leads to impaired myogenesis and enhanced muscle protein degradation, the major features of muscle wasting, via IGF signaling inhibition. Moreover, conditioned medium from Capan-1 pancreatic cancer cells, which contains abundant IGFBP-3, significantly induces muscle cell wasting. This wasting effect is potently alleviated by IGFBP3 knockdown in Capan-1 cells or IGFBP-3 antibody neutralization. Strikingly, compared to muscle cells, IGF signaling and proliferation rate of Capan-1 cells were rarely affected by IGFBP-3 treatment.

Conclusions

Our results demonstrated that pancreatic cancer cells induce muscle wasting via IGFBP-3 production.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0317-z) contains supplementary material, which is available to authorized users.

Expression of PTEN and mTOR in sacral chordoma and association with poor prognosis

Sacral chordoma is an aggressive, locally invasive neoplasm, and has a poor prognosis. However, the molecular basis for the clinical behavior remains unknown. The purpose of this study was to investigate the expression of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and mammalian target of rapamycin (mTOR) in sacral chordoma, and explore their roles in the prognosis. PTEN and mTOR were detected immunohistochemically in 40 sacral chordoma tissues and 10 adjacent normal tissues. Correlations between PTEN and mTOR expression and clinicopathological factors were analyzed. Kaplan-Meier survival curves and log-rank test were used to analyze the continuous disease-free survival time (CDFS). The expression of PTEN in sacral chordoma was significantly lower than that in adjacent normal tissues, while the levels of mTOR expression in sacral chordoma were significantly higher than that in adjacent normal tissues (P = 0.000, P = 0.030). The positive expression of mTOR appears to correlate with the negative expression of PTEN in sacral chordoma (P = 0.021). PTEN-negative expression and mTOR-positive expression were associated with tumor invasion into the surrounding muscles (P = 0.038, P = 0.014). Log-rank test showed that PTEN-negative and mTOR-positive expressions had an important impact on the patients' CDFS (P = 0.011, P = 0.015). Our results suggest that PTEN and mTOR might play an important role in the local invasiveness of sacral chordoma. PTEN and mTOR might be recognized as important prognostic predictors of recurrence and could be used as potential therapeutic targets for the treatment for sacral chordoma.

Effect of PTEN antisense oligonucleotide on oesophageal squamous cell carcinoma cell lines

OBJECTIVE

To investigate the effects of a phosphatase and tensin homologue (PTEN) antisense oligonucleotide on PTEN and mammalian target of rapamycin (mTOR) mRNA and protein, cell proliferation and apoptosis in oesophageal squamous cell carcinoma (OCSS) cell lines.

METHODS

EC9706 and EC1 cells were transfected with PTEN antisense oligonucleotide, sense oligonucleotide or nonsense oligonucleotide. Cell proliferation and apoptosis were quantified. Immuno cyto chemistry and in situ hybridization were used to determine PTEN and mTOR protein and mRNA levels, respectively.

RESULTS

Transfection with PTEN antisense oligonucleotide dose- and time-dependently enhanced cell proliferation and inhibited apoptosis in both EC9706 and EC1 cells. PTEN mRNA and protein were significantly downregulated, and mTOR protein and mRNA were significantly upregulated.

CONCLUSION

These data suggest that PTEN is an important tumour suppressor gene in the development of OSCC.

Immunohistochemical expression of mTOR negatively correlates with PTEN expression in gastric carcinoma

The phosphoinositide-3 kinase (PI3K)-AKT-mammalian target of rapamycin (mTOR) pathway is a cellular pathway involved in cell growth, tumorigenesis and cell invasion which is frequently activated in various types of cancer. The downstream effector of the pathway is mTOR which is important in cellular growth and homeostasis and aberrant activation of mTOR has been reported in several types of cancer. The tumor suppressor gene phosphatase and tensin homolog (PTEN) is essential in this pathway for inhibiting tumor invasion and metastasis. However, the involvement of mTOR and PTEN in the progression of human gastric cancer remains to be identified. Immunohistochemical staining was performed to detect the expression of mTOR and PTEN in paraffin-embedded gastric tissue sections obtained from 33 patients with gastric cancer and 30 normal controls. The expressed mTOR was mainly distributed in the cytoplasm, while PTEN was mainly localized to the nucleus. By considering negative mTOR expression with positive PTEN expression as one group and negative PTEN expression with positive mTOR expression as the other, significant statistical differences were observed in various categories, including histological types and metastatic and clinical pathology stages, between the 2 groups (P<0.01 or 0.05). The results indicated that the expression levels of mTOR and PTEN were negatively correlated in the PI3K-AKT-mTOR signaling pathway. Combined detection of mTOR and PTEN expression may be used to evaluate the degree of malignancy in gastric cancer and may be a useful marker for the early diagnosis of gastric cancer.

Notch-1 inhibition by Withaferin-A: a therapeutic target against colon carcinogenesis

Notch signaling plays a crucial role in the development of colon cancer; targeting the Notch pathway may sensitize colon cancers to various adjuvant agents. The focus of our current study is to identify natural compounds that target Notch signaling and that might be beneficial for the prevention and treatment of colon cancer. Withaferin-A (WA) is a bioactive compound derived from Withania somnifera, which inhibits Notch-1 signaling and downregulates prosurvival pathways, such as Akt/NF-kappaB/Bcl-2, in three colon cancer cell lines (HCT-116, SW-480, and SW-620). In addition, WA downregulated the expression of mammalian target of rapamycin signaling components, pS6K and p4E-BP1, and activated c-Jun-NH(2)-kinase-mediated apoptosis in colon cancer cells. We also established the molecular link between Notch/Akt/mammalian target of rapamycin signaling by complementary approaches (i.e., overexpression of Notch-1 or inhibition of Notch-1 by small interfering RNA). Our results suggest that WA inhibits Notch-mediated prosurvival signaling, which facilitates c-Jun-NH(2)-kinase-mediated apoptosis in colon cancer cell lines. These results underscore the anticancer activity of WA, which exhibits potential for further development for targeted chemotherapy and/or chemoprevention strategies in the context of colon cancer.

Bone marrow mesenchymal stem cells from leukemia patients inhibit growth and apoptosis in serum-deprived K562 cells

BACKGROUND

The regulation of growth and apoptosis in K562 cells by human bone marrow mesenchymal stem cells (MSCs) from leukemia patients was investigated.

METHODS

K562 cells were cocultured with leukemic MSCs under serum deprivation. Cell Counting Kit-8 (CCK-8), PI staining, Annexin V/PI binding and FACS assays were used to investigate cell proliferation, cell cycle status, and apoptosis of K562 cells cultures in the presence or absence of 10% serum. Western blotting was used to determine the levels of Akt, phosphorylated Akt (p-Akt), the BCL-2 family member Bad, and phosphorylated Bad (p-Bad) proteins in K562 cells after coculturing with MSCs. The effects of LY294002 (a specific inhibitor of PI3K) on protein expression were also determined.

RESULTS

K562 cell proliferation was inhibited by coculture with MSCs and the dominant cell cycle was the G0-G1 phase. The proportion of apoptotic K562 cells was decreased and the levels of p-Akt and p-Bad were upregulated after exposing K562 cells to MSCs. However, when LY294002 was used, p-Akt and p-Bad proteins inK562 cells showed a significant reduction, while no distinct variation was seen in the nonphosphorylated Akt and Bad protein levels.

CONCLUSION

Leukemic MSCs can inhibit K562 cell expansion and modulate the cell cycle to a state of relative quiescence. This allows the K562 cells to endure adverse conditions such as serum starvation. The PI3K-Akt-Bad signaling pathway may be involved in this antiapoptotic process via phosphorylation of the Akt and Bad proteins. Blocking MSC-induced transduction of the PI3K-Akt-Bad pathway may be a potential strategy for a targeted therapy to combat leukemia.