TUSC3 inhibits cell proliferation and invasion in cervical squamous cell carcinoma via suppression of the AKT signalling pathway

The decreased expression of tumour suppressor candidate 3 (TUSC3) is associated with proliferation in several types of cancer, leading to an unfavourable prognosis. The present study aimed to assess the cellular and molecular function of TUSC3 in patients with cervical squamous cell carcinoma (CSCC). Levels of mRNA expressions of TUSC3 were analysed in CSCC tissues and six cell lines using qRT‐PCR. Immunohistochemistry(IHC) was used to evaluate the protein expression level of TUSC3 in four paired specimens, 220 paraffin‐embedded CSCC specimens and 60 cases of normal cervical tissues(NCTs), respectively. Short hairpin RNA interference was employed for TUSC3 knockdown. Cell proliferation, migration and invasion were evaluated using growth curve, MTT assay, wound healing, transwell assay and xenograft tumour model, respectively. The results demonstrated that TUSC3 mRNA and protein expression levels were downregulated in CSCC samples. Multivariate and univariate analyses indicated that TUSC3 was an independent prognostic factor for patients with CSCC. Decreased TUSC3 expression levels were significantly associated with proliferation and an aggressive phenotype of cervical cancer cells both in vitro and in vivo. Moreover, the knockdown of TUSC3 promoted migration and invasion of cancer cells, while the increased expression of TUSC3 exhibited the opposite effects. The downregulation of TUSC3 facilitated proliferation and invasion of CSCC cells through the activation of the AKT signalling pathway. Our data demonstrated that the downregulation of TUSC3 promoted CSCC cell metastasis via the AKT signalling pathway. Therefore, TUSC3 may serve as a novel prognostic marker and potential target for CSCC.     

Retracted: Sapylin inhibits lung cancer cell proliferation and promotes apoptosis by attenuating PI3K/AKT signaling

Sapylin (OK-432) revealed biological properties in cancers. In this study, the effect of sapylin on lung cancer cell A549 was investigated. A549 cell lines were treated with sapylin (0.1, 0.5, and 1 KE/mL) for different time intervals. A549 cell proliferation and apoptosis was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide/Ki67 assay and flow cytometry, respectively. Western blot was used to determine the expressions of proteins involved in proliferation, apoptosis, and phosphoinositide 3-kinase/serine/threonine kinase (PI3K/AKT), Wnt3a/β-catenin signaling pathway. Level of intracellular reactive oxygen species (ROS) was insured by using the ROS kit. Sapylin inhibited A549 cell viability and the expressions of proliferation-related proteins (cyclin E1 and D1) in dose- and time-dependent manners. Sapylin promoted apoptosis in a dose- and time-dependent manners. Sapylin also promoted the expressions of apoptotic proteins (cleaved caspase-3 and 8) in dose- and time-dependent manners. Furthermore, sapylin increased the intracellular concentration of ROS in a dose-dependent manner. Besides, the high expression of ROS level might induce inhibition of cell viability and increase cell apoptosis. The mechanistic study revealed that sapylin inactivated the PI3K/AKT and Wnt3a/β-catenin signaling pathways. Our findings suggest that sapylin inhibits proliferation and promotes apoptosis in lung cancer cells, thus providing a new theoretical basis for the treatment of lung cancer.     

miR-206 inhibits thyroid cancer proliferation and invasion by targeting RAP1B

Thyroid cancer (TC) is one of the primary tumors arisen from endocrine system. The purpose of this study was to investigate the underlying mechanism by which RAP1B (Ras-related protein Rap-1b) modulates microRNA (miR)-206 related effects on TC cells. Expression of miR-206 and RAP1B was analyzed in cells and tissues. miR-206 mimics or inhibitors and RAP1B vector were used in functional experiments to investigate the effects of miR-206 and RAP1B on cell activities including proliferation, migration, and invasion. Luciferase assay was performed to explore the association between miR-206 and RAP1B. The influence of miR-206 on tumorigenesis of TC cells was investigated using an ex vivo model. Our results demonstrated the reduce of miR-206 in TC tissues and cell lines in which RAP1B was increased. Overexpression of miR-206 significantly inhibited the functional capacities of TPC-1 cells including proliferation, invasion, and migration, most likely, through reducing the expression of RAP1B. Xenograft experiment showed that increased miR-206 could effectively inhibit the tumorigenesis of TC cells. Our study showed that miR-206 negatively regulated cell activities of proliferation, invasion, and migration in TC via suppressing RAP1B expression, suggesting that miR-206 exerts a vital role in TC.     

Injury-induced activation of the MAPK/CREB pathway triggers apoptosis-induced compensatory proliferation in hydra head regeneration

After bisection, Hydra polyps regenerate their head from the lower half thanks to a head-organizer activity that is rapidly established at the tip. Head regeneration is also highly plastic as both the wild-type and the epithelial Hydra (that lack the interstitial cell lineage) can regenerate their head. In the wild-type context, we previously showed that after mid-gastric bisection, a large subset of the interstitial cells undergo apoptosis, inducing compensatory proliferation of the surrounding progenitors. This asymmetric process is necessary and sufficient to launch head regeneration. The apoptotic cells transiently release Wnt3, which promotes the formation of a proliferative zone by activating the beta-catenin pathway in the adjacent cycling cells. However the injury-induced signaling that triggers apoptosis is unknown. We previously reported an asymmetric immediate activation of the mitogen-activated protein kinase/ribosomal S6 kinase/cAMP response element binding protein (MAPK/RSK/CREB) pathway in head-regenerating tips after mid-gastric bisection. We show here that pharmacological inhibition of the MAPK/ERK pathway or RNAi knockdown of the RSK, CREB, CREB binding protein (CBP) genes prevents apoptosis, compensatory proliferation and blocks head regeneration. As the activation of the MAPK pathway upon injury plays an essential role in regenerating bilaterian species, these results suggest that the MAPK-dependent activation of apoptosis-induced compensatory proliferation represents an evolutionary-conserved mechanism to launch a regenerative process.     

Dieckol inhibits non‐small–cell lung cancer cell proliferation and migration by regulating the PI3K/AKT signaling pathway

Non‐small–cell lung cancer (NSCLC) is one of the most prevalent type of lung cancers with an increased mortality rate in both developed and developing countries worldwide. Dieckol is one such polyphenolic drug extracted from brown algae which has proven antioxidant and anti‐inflammatory properties. In the present study, we evaluated the anticancer property of dieckol against NSCLC cell line A549. The LC₅₀ value of dieckol was found to be 25 µg/mL by performing 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay and the antiapoptotic property of dieckol was analyzed by dual staining technique with acridine orange/propidium iodide (AO/PI) stains. It was further confirmed with flow cytometry analysis with Annexin FITC and JC‐1 staining and the anti‐invasive property was assessed by Transwell assay. The molecular mechanism of dieckol anticancer activity was confirmed by estimating the levels of caspases and by estimating the signaling proteins of Pi3K/AKT/mTOR signaling pathway using the immunoblotting technique. Our data suggest that dieckol is potent anticancer agent, it effectively inhibits the invasive and migratory property A549 cells and it also induces apoptosis via inhibiting Pi3K/AKT/mTOR signaling, activating the tumor suppressor protein E‐cadherin signifying that dieckol is potent natural anticancer drug to treat NSCLC.     

The RNA recognition motif domains of RBM5 are required for RNA binding and cancer cell proliferation inhibition

RBM5 is a known putative tumor suppressor gene that has been shown to function in cell growth inhibition by modulating apoptosis. RBM5 also plays a critical role in alternative splicing as an RNA binding protein. However, it is still unclear which domains of RBM5 are required for RNA binding and related functional activities. We hypothesized the two putative RNA recognition motif (RRM) domains of RBM5 spanning from amino acids 98–178 and 231–315 are essential for RBM5-mediated cell growth inhibition, apoptosis regulation, and RNA binding. To investigate this hypothesis, we evaluated the activities of the wide-type and mutant RBM5 gene transfer in low-RBM5 expressing A549 cells. We found that, unlike wild-type RBM5 (RBM5-wt), a RBM5 mutant lacking the two RRM domains (RBM5-ΔRRM), is unable to bind RNA, has compromised caspase-2 alternative splicing activity, lacks cell proliferation inhibition and apoptosis induction function in A549 cells. These data provide direct evidence that the two RRM domains of RBM5 are required for RNA binding and the RNA binding activity of RBM5 contributes to its function on apoptosis induction and cell growth inhibition.     

VLX1570 regulates the proliferation and apoptosis of human lung cancer cells through modulating ER stress and the AKT pathway

The ubiquitin‐proteasome system (UPS) possesses unique functions in tumorigenesis and has great potential for targeting tumours. The effectiveness of inhibitors targeting UPS in solid tumours remains to be studied. We screened a library of inhibitors targeting the ubiquitination system and found the highly potent, low‐concentration inhibitor molecule VLX1570 that specifically killed lung cancer cells. VLX1570 is an inhibitor of deubiquitinating enzyme activity and has also shown potential for preclinical cancer treatment. We found that VLX1570 significantly inhibited lung cancer cells proliferation and colony formation. VLX1570 induced a G2/M cell cycle arrest by downregulating CDK1 and CyclinB1. Moreover, VLX1570 significantly promoted the mitochondrial‐associated apoptosis. Mechanistically speaking, VLX1570 activated the PERK/IRE1/ATF6 pathway and induced ER stress in lung cancer cell lines. The inhibition of ER stress by tauroursodeoxycholic acid sodium or 4‐phenylbutyric acid enhanced VLX1570‐induced apoptosis. In addition, VLX1570 treatment led to the inactivation of Akt signalling and inhibited the proliferation of lung cancer cells by downregulating the Akt pathway. Moreover, combined treatment with VLX1570 and Afatinib or Gefitinib induced synergistic anti‐lung cancer activity. Our present study demonstrated a novel therapy using VLX1570, which inhibited the proliferation and increased apoptosis in human lung cancer.     

Yak OXGR1 promotes fibroblast proliferation via the PI3K/AKT pathways

Oxoglutarate receptor 1 (OXGR1), as one of the intermediates in G protein-coupled receptors (GPCRs), plays a crucial role in the citric acid cycle receptor of α-ketoglutarate and metabolism. GPCR can control the cell proliferation by regulating the downstream signaling of G protein signaling pathways. The PI3K/AKT pathway transmits the downstream signals of GPCRs and receptor tyrosine kinases. However, the specific role of OXGR1 promoting cell proliferation and differentiation are still unknown. In current study, the over-expression vector and knockdown sequence of yak OXGR1 were transfected into yak fibroblasts, and the effects were detected by a series of assays. The results revealed that OXGR1 expression in yak lung parenchyma tissue was significantly higher than that of other tissues. In yak fibroblasts, the upregulated expression of OXGR1 resulted in activating the PIK3CG (downstream signal) of the PI3K/AKT1 pathway that can upregulated the expression of proliferation genes ( CDK1, PCNA, and CyclinD1) and promote cell proliferation. Conversely, the downregulated expression of OXGR1 inhibited cell proliferation via PI3K/AKT1 pathway. Cell cycle and cell proliferation assays demonstrated that over-expression of OXGR1 can enhanced the DNA synthesis and promoted yak fibroblasts proliferation. While the conversely, knockdown of OXGR1 can decreased DNA synthesis and inhibited cell proliferation. These results illustrated that changes of OXGR1 expression can trigger the fibroblasts proliferation via PI3K/AKT signaling pathway, which indicating that OXGR1 is a novel regulator for cell proliferation and differentiation. Furthermore, these results provide evidence supporting the functional role of GPCRs-PI3K-AKT1 and OXGR1 in cell proliferation.     

SLC1A3 promotes gastric cancer progression via the PI3K/AKT signalling pathway

Gastric cancer is a major cause of mortality worldwide. The glutamate/aspartate transporter SLC1A3 has been implicated in tumour metabolism and progression, but the roles of SLC1A3 in gastric cancer remain unclear. We used bioinformatics approaches to analyse the expression of SLC1A3 and its role in gastric cancer. The expression levels of SLC1A3 were examined using RT‐qPCR and Western bolting. SLC1A3 overexpressing and knock‐down cell lines were constructed, and the cell viability was evaluated. Glucose consumption, lactate excretion and ATP levels were determined. The roles of SLC1A3 in tumour growth were evaluated using a xenograft tumour growth model. SLC1A3 was found to be overexpressed in gastric cancer, and this overexpression was associated with poor prognosis. In vitro and in vivo assays showed that SLC1A3 affected glucose metabolism and promoted gastric cancer growth. GSEA analysis suggested that SLC1A3 was positively associated with the up‐regulation of the PI3K/AKT pathway. SLC1A3 overexpression activated the PI3K/AKT pathway and up‐regulated GLUT1, HK II and LDHA expression. The PI3K/AKT inhibitor LY294002 prevented SLC1A3‐induced glucose metabolism and cell proliferation. Our findings indicate that SLC1A3 promotes gastric cancer progression via the PI3K/AKT signalling pathway. SLC1A3 is therefore a potential therapeutic target in gastric cancer.     

miR-377-5p inhibits lung cancer cell proliferation,invasion, and cell cycle progression by targeting AKT1 signaling

Lung carcinoma is the most common type of malignant tumors globally, and its molecular mechanisms remained unclear. With the aim to investigate the effects of microRNA (miR)-377-5p on the cell development, invasion, metastasis, and cycle of lung carcinoma, this study was performed. We evaluated miR-377-5p expression levels in lung cancer tissues and cell models. Cell viability, proliferation, migration, invasion abilities, and cell cycle distribution were measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, crystal violet, transwell, and flow cytometry assay. Furthermore, expression levels of protein kinase B α subunit (AKT1) and proteins related to cell cycle and epithelial-mesenchymal transition (EMT) were assessed using Western blot analysis and quantitative real-time polymerase chain reaction. These results suggested that miR-377-5p was downregulated in vivo and in cell models, and miR-377-5p overexpression inhibited cell viability, proliferation, migration, invasion, and induced cell-cycle arrest. In addition, as a target of miR-377-5p, AKT1 alleviated the decreases of cell viability, proliferation, migration, invasion, the S-phase cells, the expression of cyclin D1, fibronectin, and vimentin, as well as the increases of the G0/G1-phase cells, the expression of Foxo1, p27 ^kip1, p21 ^Cip1 and E-cadherin when miR-377-5p overexpressed. In conclusion, miR-377-5p inhibited cell development and regulated cell cycle distribution and EMT by targeting AKT1, which provided a theoretical basis for further study of lung carcinoma therapeutics.     

LncRNA MEG3 inhibits rheumatoid arthritis through miR‐141 and inactivation of AKT/mTOR signalling pathway

Rheumatoid arthritis (RA) is a chronic inflammation mediated by autoimmune responses. MEG3, a kind of long noncoding RNA (lncRNA), participates in cell proliferation in cancer tissues. However, the correlation between MEG3 and RA is yet unclear. Therefore, to clarify how MEG3 works in RA, we performed a series of experiments using RA samples. We found that MEG3 was downregulated in the fibroblast‐like synoviocytes of RA patients (RA‐FLS), in comparison with healthy subjects. MEG3 was also down‐regulated evidently in lipopolysaccharide (LPS)‐treated chondrocyte. As part of our experiments, MEG3 was overexpressed in chondrocyte by transfection with lentivirus containing sequences encoding MEG3. In addition, in presence of LPS, reductions were identified not only in the cell proliferation, but also in the generation of interleukin‐23 (IL‐23), which, however were reversed in the lentivirus (containing MEG3‐encoding sequences)‐transfected chondrocytes. Up‐regulated MEG3 resulted in an increase the level of Ki67. Moreover, MEG3 was negatively correlated with miR‐141, and miR‐141 was up‐regulated in LPS‐treated chondrocyte. Inhibitory effects of MEG3 overexpression, mentioned above, were partially abolished by overexpressed miR‐141. Further, animal experiment also showed the inhibitory effect of MEG3 in overexpression on the AKT/mTOR signaling pathway. In‐vivoexperiments also showed that cell proliferation was facilitated by MEG3 overexpression with inhibited inflammation. In summary, the protective role of MEG3 in RA was proved to be exerted by the increase in the rate of proliferation, which might correlate to the regulatory role of miR‐141 and AKT/mTOR signal pathway, suggesting that MEG3 holds great promise as a therapeutic strategy for RA.     

Reduced CENPU expression inhibits lung adenocarcinoma cell proliferation and migration through PI3K/AKT signaling

CENPU (centromere protein U), a centromere component essential for mitosis, relates with some cancers progression. However, it is not well illustrated in lung adenocarcinoma (LAC). Here, we aimed to investigate the potential effect of CENPU on LAC progression and prognosis. In this experiment, expression level of CENPU and association between its expression and LAC patients’ clinicopathological characteristics and prognosis were analyzed. The proliferation, migration and invasive abilities of LAC cells were determined by CCK-8, colony formation, transwell assays. Western blot was used to detect PI3K/AKT signaling key proteins. We found CENPU level was overexpressed in LAC tissues on comparing normal tissues. Moreover, CENPU overexpression correlated with clinicopathological variables and predicted an independent prognostic indicator in LAC patients. Functionally, CENPU downregulation significantly inhibited LAC cell proliferation, migration and invasion in, which was possibly mediated by PI3K/AKT pathway inactivation. Our findings insinuate targeting CENPU may be a potential therapeutic strategy for LAC.