The depletion of PinX1 involved in the tumorigenesis of non-small cell lung cancer promotes cell proliferation via p15/cyclin D1 pathway

Silencing PinX1 enhances radiosensitivity and antitumor-immunity of radiotherapy in non-small cell lung cancer

BACKGROUND

We aimed to investigate the effects of PinX1 on non-small cell lung cancer(NSCLC) radiosensitivity and radiotherapy-associated tumor immune microenvironment and its mechanisms.

METHODS

The effect of PinX1 silencing on radiosensitivity in NSCLC was assessed by colony formation and CCK8 assay, immunofluorescence detection of γ- H2AX and micronucleus assay. Western blot was used to assess the effect of PinX1 silencing on DNA damage repair pathway and cGAS-STING pathway. The nude mouse and Lewis lung cancer mouse model were used to assess the combined efficacy of PinX1 silencing and radiotherapy in vivo. Changes in the tumor immune microenvironment were assessed by flow cytometry for different treatment modalities in the Lewis luuse model. The interaction protein RBM10 was screened by immunoprecipitation-mass spectrometry.

RESULTS

Silencing PinX1 enhanced radiosensitivity and activation of the cGAS-STING pathway while attenuating the DNA damage repair pathway. Silencing PinX1 further increases radiotherapy-stimulated CD8+ T cell infiltration and activation, enhances tumor control and improves survival in vivo; Moreover, PinX1 downregulation improves the anti-tumor efficacy of radioimmunotherapy, increases radioimmune-stimulated CD8+ T cell infiltration, and reprograms M2-type macrophages into M1-type macrophages in tumor tissues. The interaction of PinX1 and RBM10 may promote telomere maintenance by assisting telomerase localization to telomeres, thereby inhibiting the immunostimulatory effects of IR.

CONCLUSIONS

In NSCLC, silencing PinX1 significantly contributed to the radiosensitivity and promoted the efficacy of radioimmunotherapy. Mechanistically, PinX1 may regulate the transport of telomerase to telomeres through interacting with RBM10, which promotes telomere maintenance and DNA stabilization. Our findings reveal that PinX1 is a potential target to enhance the efficacy of radioimmunotherapy in NSCLC patients.

A novel lupene derivative from Thymus capitatus possesses an apoptosis-inducing effect via Let-7 miRNA/Cyclin D1/VEGF cascade in the A549 cell line

Non-small-cell lung carcinoma (NSCLC) is a type of epithelial lung cancer accounting for about 85% of all lung cancers. In our research, a novel lupene derivative namely acetoxy-lup-5(6), 20(29)-diene (ALUP), as well as two known triterpenes; lupeol (LUP) and betulinic acid (BA) were isolated through the chromatographic purification of the 95% ethanolic extract of Thymus capitatus. Identification of the compounds was carried out by physicochemical properties as well as spectral 1D and 2D NMR analysis. The anti-cancer activity of the three triterpenes was assessed on non-small cell lung cancer cell line; A549 using MTT assay and cell cycle analysis using annexin V/propidium iodide. The molecular mechanism underlying anti-apoptotic effects was determined by analyzing Let-7 miRNA and miRNA-21 expression, the mRNA gene expression level of Bax, CASP-8, CD95, Bcl2, KRAS, VEGF, Cyclin D1 using qRT-PCR. Our results revealed that the three isolated compounds ALUP, LUP, and BA caused cell cycle arrest at the G2/M phase with an increase in the apoptosis which may be attributed to their significant effect on raising Bax, CASP-8, and CD95 and reducing the mRNA expression levels of Bcl-2, KRAS, VEGF, and Cyclin D1 compared to control cells. RT-PCR results showed that the ALUP, LUP, and BA significantly downregulated miRNA-21 expression. Meanwhile, the three compounds caused significant overexpression of Let-7 miRNA. This is the first report on the anti-cancer activity of acetoxy-lup-5(6), 20(29)-diene (ALUP) in reducing the proliferation and differentiation of the A549 cell line through inducing apoptosis. Finally, by targeting the Let-7 miRNA/Cyclin D1/VEGF cascade, acetoxy-lup-5(6), 20(29)-diene could be a potential therapeutic agent for lung cancer.

HDAC6 deacetylates IDH1 to promote the homeostasis of hematopoietic stem and progenitor cells

Hematopoietic stem and progenitor cells (HSPCs) are cells mainly present in the bone marrow and capable of forming mature blood cells. However, the epigenetic mechanisms governing the homeostasis of HSPCs remain elusive. Here, we demonstrate an important role for histone deacetylase 6 (HDAC6) in regulating this process. Our data show that the percentage of HSPCs in Hdac6 knockout mice is lower than in wild-type mice due to decreased HSPC proliferation. HDAC6 interacts with isocitrate dehydrogenase 1 (IDH1) and deacetylates IDH1 at lysine 233. The deacetylation of IDH1 inhibits its catalytic activity and thereby decreases the 5-hydroxymethylcytosine level of ten-eleven translocation 2 (TET2) target genes, changing gene expression patterns to promote the proliferation of HSPCs. These findings uncover a role for HDAC6 and IDH1 in regulating the homeostasis of HSPCs and may have implications for the treatment of hematological diseases.

The β-catenin-LINC00183-miR-371b-5p-Smad2/LEF1 axis promotes adult T-cell lymphoblastic lymphoma progression and chemoresistance

BACKGROUND

High-intensity chemotherapy regimens are often used in adult T-cell lymphoblastic lymphoma (T-LBL) patients. Nevertheless, the response rate remains unsatisfactory due to emergence of chemoresistance. Growing evidence has shown that long non-coding RNAs (lncRNAs) are involved in tumor progression and chemoresistance. Herein, we investigated the potential role of lncRNAs in T-LBLs.

METHODS

RNAseq was used to screen and identify candidate lncRNAs associated with T-LBL progression and chemoresistance. Luciferase reporter assay was used to examine the binding of miR-371b-5p to the 3'UTR of Smad2 and LEF1, and the binding of TCF-4/LEF1 to the promoter of LINC00183. Chromatin immunoprecipitation assay was undertaken to analyze the connection between LEF1 and the LINC00183 promoter region. RNA immunoprecipitation assays were used to explore the mechanism whereby LINC00183 regulated miR-371b-5p. MTT and flow cytometry assays were used to measure apoptosis of T-LBL cells.

RESULTS

LINC00183 was upregulated in T-LBL progression and chemoresistant tissues in both the Sun Yat-sen University Cancer Center dataset and the First Affiliated Hospital of Anhui Medical University dataset. High expression of LINC00183 was correlated with poorer overall survival and progression-free survival of T-LBL patients compared to those with low expression of LINC00183. Furthermore, miR-371b-5p was negatively regulated by LINC00183. In vivo and in vitro assays showed that LINC00183-mediated T-LBL chemoresistance depended on miR-371b-5p expression. The direct binding of miR-371b-5p to Smad2 and LEF1 was verified by luciferase assays. It was shown that TCF4/LEF1 could bind to the LINC00183 promoter site and increase its transcript level. Downregulation of miR-371b-5p led to increased expression of Smad2/LEF1, and in turn increased LINC00183 expression. Additionally, phospho-Smad2 promotes nuclear translocation of β-catenin, LINC00183 downregulation decreased chemoresistance induced by β-catenin and TGF-β1 in T-LBL cells.

CONCLUSION

We unraveled a β-catenin-LINC00183-miR-371b-5p-Smad2/LEF1 feedback loop that promotes T-LBL progression and chemoresistance, indicating that LINC00183 may serve as a potential therapeutic target in T-LBLs.

Arteannuin B Enhances the Effectiveness of Cisplatin in Non-Small Cell Lung Cancer by Regulating Connexin 43 and MAPK Pathway

Cisplatin (DDP)-based chemotherapy is the first-line regimen for advanced non-small cell lung cancer (NSCLC) patients. However, advanced NSCLC patients may have innate resistance to DDP or develop resistance during DDP treatment. We investigated a natural compound, arteannuin B (Art B), for its potential effects on DDP resistance in NSCLC. Art B was isolated from Artemisia annua by chromatographic purification and spectral elucidation. The activities of Art B on DDP-mediated effects were examined using in vitro and in vivo assays. We observed significant correlations in T stage, clinical stage, chemotherapy resistance and poor survival of NSCLC patients with low Cx43 expression. Art B enhanced the effectiveness of cisplatin by increasing Cx43 expression in normal and DDP-resistant NSCLC cells. Art B also increased DDP uptake through up-regulating Cx43. The combination of DDP and Art B showed better therapeutic effect than individual treatments both in vitro and in vivo. Art B increased intracellular Fe[Formula: see text] level, promoted calcium influx, and activated gap junction and MAPK pathways, which might contribute to Art B-mediated effects. Art B may serve as a new drug candidate to enhance the antitumor effect of DDP on NSCLC.

Identifying General Tumor and Specific Lung Cancer Biomarkers by Transcriptomic Analysis

The bioinformatic pipeline previously developed in our research laboratory is used to identify potential general and specific deregulated tumor genes and transcription factors related to the establishment and progression of tumoral diseases, now comparing lung cancer with other two types of cancer. Twenty microarray datasets were selected and analyzed separately to identify hub differentiated expressed genes and compared to identify all the deregulated genes and transcription factors in common between the three types of cancer and those unique to lung cancer. The winning DEGs analysis allowed to identify an important number of TFs deregulated in the majority of microarray datasets, which can become key biomarkers of general tumors and specific to lung cancer. A coexpression network was constructed for every dataset with all deregulated genes associated with lung cancer, according to DAVID’s tool enrichment analysis, and transcription factors capable of regulating them, according to oPOSSUM´s tool. Several genes and transcription factors are coexpressed in the networks, suggesting that they could be related to the establishment or progression of the tumoral pathology in any tissue and specifically in the lung. The comparison of the coexpression networks of lung cancer and other types of cancer allowed the identification of common connectivity patterns with deregulated genes and transcription factors correlated to important tumoral processes and signaling pathways that have not been studied yet to experimentally validate their role in lung cancer. The Kaplan–Meier estimator determined the association of thirteen deregulated top winning transcription factors with the survival of lung cancer patients. The coregulatory analysis identified two top winning transcription factors networks related to the regulatory control of gene expression in lung and breast cancer. Our transcriptomic analysis suggests that cancer has an important coregulatory network of transcription factors related to the acquisition of the hallmarks of cancer. Moreover, lung cancer has a group of genes and transcription factors unique to pulmonary tissue that are coexpressed during tumorigenesis and must be studied experimentally to fully understand their role in the pathogenesis within its very complex transcriptomic scenario. Therefore, the downstream bioinformatic analysis developed was able to identify a coregulatory metafirm of cancer in general and specific to lung cancer taking into account the great heterogeneity of the tumoral process at cellular and population levels.

Hesperidin Inhibits Lung Cancer In Vitro and In Vivo Through PinX1

New drugs or active leads with high efficiency and low toxicity are needed in the treatment of lung cancer. Natural products are an important source of anti-tumor drugs. At present, there are many molecular-targeted anti-tumor drugs derived from natural products or their derivatives for tumor treatment or in clinical trials. Hesperidin is a flavanone isolated from the Rutaceae plant lime Citrus aurantium L. or Citrus sinensis Osbeck. It has been considered to inhibit cancer cell viability in vitro. However, the effect of hesperidin on lung cancer and its underlying mechanism remain unclear. In this study, we found that the pinX1 expression level is closely related to overall survival and plays an important role in regulating lung cancer cell proliferation, migration, invasion, and senescence. More importantly, hesperidin significantly increased pinX1 protein expression, and knockdown pinX1 by its specific siRNA blocked the protective effects of hesperidin. Moreover, we also assessed that hesperidin at 100 mg/kg is safe in vivo. These findings showed that hesperidin is a potential therapeutic candidate for preventing the progression of lung cancer.

PINX1 promotes malignant transformation of thyroid cancer through the activation of the AKT/MAPK/β-catenin signaling pathway

Although thyroid cancer is the most prevalent endocrine malignancy, overall patients with thyroid cancer have a good long-term survival. However, a small percentage of patients with progressive thyroid cancer have poor outcomes, and the genetic drivers playing a key role thyroid cancer progression are mostly unknown. Here, we investigated the role of the PINX1 in thyroid cancer progression. Interestingly, PINX1 expression was significantly higher in ATC than in PTC in both patients and cell lines. When PINX1 was knockdown in ATC cells, cell proliferation rates, colony formation capacity, and cell cycle progression were significantly reduced. Furthermore, cell motility and the expression of EMT drivers were reduced by PINX1 downregulation. In contrast, the overexpression of PINX1 in PTC cells significantly increased those phenotypes of tumor progression, which demonstrates that PINX1 could promote tumor proliferation and malignant transformation in both PTC and ATC cells. To further understand whether PINX1 is also involved in the progression of PTC to ATC, we examined PI3K/AKT, MAPK, and β-catenin signaling activation after PINX1 modulation. Decreased PINX1 expression reduced the levels of p-AKT, p-ERK, p-p38, and β-catenin in ATC cells, but the increase of PINX1 expression upregulated the phosphorylation of AKT, ERK, and p38 and the levels of β-catenin in PTC cells. These results were all confirmed in xenograft mouse tumors. Our findings suggest that PINX1 regulates thyroid cancer progression by promoting cell proliferation, EMT, and signaling activation, and support the hypothesis that PINX1 could be a prognostic marker and a therapeutic target of thyroid cancer.

Abnormal Expression and Prognostic Significance of Bone Morphogenetic Proteins and Their Receptors in Lung Adenocarcinoma

Background

Lung adenocarcinoma (LUAD) is one of the most life-threatening malignancies. The crucial role of bone morphogenetic protein (BMP)/BMP receptors reveals the significance of exploring BMP protein-related prognostic predictors in LUAD.

Methods

The mRNA expression of BMPs/BMP receptors was investigated in LUAD and normal lung tissues. Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed, and the prognostic values were assessed by Kaplan-Meier Plotter. Univariate and multivariate Cox regression analyses were executed to ascertain the correlation between overall survival (OS) and the mRNA expression of BMPs/BMP receptors. The receiver operating characteristic (ROC) curves were implemented to evaluate the predictive power of the prognostic model. Then, the prognostic model was validated in the GEO cohort. Furthermore, a nomogram comprising the prognostic model was established.

Results

The mRNA expression of BMP2/5/6/R2, ACVRL1, and TGFBR2/3 was lower in LUAD tissues than in normal lung tissues. High expression of BMP2/4/5/R1A/R2, ACVR1/2A/L1, and TGFBR1/3 was associated with better OS, while BMP7 and ACVR1C/2B were associated with poorer OS. Three genes (BMP5, BMP7, and ACVR2A) were screened by univariate and multivariate Cox regression analyses to develop the prognostic model in TCGA. Significantly better survival was observed in LUAD patients with a low-risk score than those with a high-risk score. The ROC curves confirmed the good performance of the prognostic model, then, the prognostic model was validated in the GSE31210 dataset. A nomogram was constructed (AUCs>0.7). And hub genes were further evaluated, including gene set enrichment analysis and immune cell infiltration.

Conclusions

BMP5, BMP7, and ACVR2A are potential therapeutic targets in LUAD. The three-gene prognostic model and the nomogram are reliable tools for predicting the OS of LUAD patients.

Keratin 17 Suppresses Cell Proliferation and Epithelial-Mesenchymal Transition in Pancreatic Cancer

Keratin 17 (K17), a member of type I acidic epithelial keratin family, has been reported to be upregulated in many malignant tumors and to be involved in promoting the development of tumors. However, the precise role of K17 in progression of pancreatic cancer is still unknown. In this study, we found that K17 expression was highly expressed in pancreatic cancer tissues and cell lines and that upregulated expression was associated with the pathological grade and poor prognosis. K17 expression served as an independent predictor of pancreatic cancer survival. Meanwhile, we showed that knocking down K17 induced pancreatic cancer cell proliferation, colony formation and tumor growth in xenografts in mice. However, K17 upregulation inhibited pancreatic cancer cell proliferation and colony formation. Further mechanistic study revealed that K17 knockdown promoted cell cycle progression by upregulating CyclinD1 expression and repressed cell apoptosis. However, K17 upregulation suppressed cell cycle progression by decreasing CyclinD1 expression, and induced apoptosis by increasing the levels of cleaved Caspase3. In addition, K17 knockdown promoted pancreatic cancer cell migration and invasion, but K17 upregulation suppressed cell migration and invasion. Moreover, knocking down K17 promoted epithelial-mesenchymal transition (EMT) in pancreatic cancer cell by inhibiting E-cadherin expression and inducing Vimentin expression, and the effects of K17 upregulation were opposite to that of K17downregulation. Taken together, our findings suggest that K17 functions as a potential tumor suppressor, even though it is upregulated in pancreatic cancer.

BRD2 induces drug resistance through activation of the RasGRP1/Ras/ERK signaling pathway in adult T-cell lymphoblastic lymphoma

BACKGROUND

Adult patients with T-cell lymphoblastic lymphoma (T-LBL) are treated with high-intensity chemotherapy regimens, but the response rate is still unsatisfactory because of frequent drug resistance. We aimed to investigate the potential mechanisms of drug resistance in adults with T-LBL.

METHODS

Gene expression microarray was used to identify differential mRNA expression profiles between chemotherapy-resistant and chemotherapy-sensitive adult T-LBL tissues. Real-time PCR and immunohistochemistry were performed to detect the expression of bromodomain-containing protein 2 (BRD2) and c-Myc in fresh-frozen T-LBL tissues from 85 adult patients. The Ras pull-down assay was performed to monitor Ras activation. Chromatin immunoprecipitation assays were used to analyze the binding of E2F transcription factor 1 (E2F1)/BRD2 to the RAS guanyl releasing protein 1 (RasGRP1) promoter region. The drug resistance effect and mechanism of BRD2 were determined by both in vivo and in vitro studies.

RESULTS

A total of 86 chemotherapy resistance-related genes in adult T-LBL were identified by gene expression microarray. Among them, BRD2 was upregulated in chemotherapy-resistant adult T-LBL tissues and associated with worse progression-free survival and overall survival of 85 adult T-LBL patients. Furthermore, BRD2 suppressed doxorubicin (Dox)-induced cell apoptosis both in vitro and in vivo. The activation of RasGRP1/Ras/ERK signaling might contribute to the Dox resistance effect of BRD2. Besides, OTX015, a bromodomain and extra-terminal (BET) inhibitor, reversed the Dox resistance effect of BRD2. Patient-derived tumor xenograft demonstrated that the sequential use of OTX015 after Dox showed superior therapeutic effects.

CONCLUSIONS

Our data showed that BRD2 promotes drug resistance in adult T-LBL through the RasGRP1/Ras/ERK signaling pathway. Targeting BRD2 may be a novel strategy to improve the therapeutic efficacy and prolong survival of adults with T-LBL.

MicroRNA-107 may regulate lung cancer cell proliferation and apoptosis by targeting TP53 regulated inhibitor of apoptosis 1

Lung cancer causes over 1.6 million mortalities worldwide annually. MicroRNAs (miRs) are involved in various types of cancer-associated processes. The present study investigated the possible mechanism of miR-107 in the development of lung cancer in order to identify novel targets for clinical treatment. The expression levels of miR-107 and its putative target gene TP53 regulated inhibitor of apoptosis 1 (TRIAP1) were measured in lung cancer tumor tissues and non-tumor adjacent tissues. Subsequently, the association between TRIAP1 and miR-107 was investigated using a dual-luciferase reporter assay. Following transfection, the effects of miR-107 and TRIAP1 on the proliferation and apoptosis of lung cancer cell lines in vitro were investigated using Cell Counting Kit-8 and flow cytometry assays, respectively. Furthermore, the regulatory effect of miR-107 on the expression levels of TRIAP1 and associated proteins was analyzed using a western blot assay. The results revealed lower expression levels of miR-107 and higher expression levels of TRIAP1 in lung cancer tumor tissues compared with non-tumor adjacent tissues. The dual-luciferase reporter assay demonstrated that TRIAP1 is a target gene of miR-107. Additionally, the results revealed that overexpression of miR-107 resulted in a lower proliferation rate and higher apoptosis rate of A549 cells, compared with the negative control (NC) and control groups (P<0.01). The variation of cell proliferation and apoptosis induced by miR-107 mimics was reversed by co-transfection with pcDNA3.1-TRIAP1. Furthermore, the expression levels of cyclin D1 and proliferating cell nuclear antigen were markedly decreased in the miR-107 mimics group compared with the NC group (P<0.01). The expression levels of BCL2 associated X apoptosis regulator, tumor protein p53 and caspase 3 were upregulated and the expression levels of TRIAP1 and BCL2 apoptosis regulator were significantly reduced in the miR-107 mimics group compared with the NC group (P<0.01). The results of the present study suggested that miR-107 regulates lung cancer cell proliferation and apoptosis by targeting TRIAP1.

Benzethonium chloride suppresses lung cancer tumorigenesis through inducing p38-mediated cyclin D1 degradation

Lung cancer is the leading cause of cancer-related deaths worldwide, but effective therapeutics is limited. This study aims to identify novel anticancer strategy from a Food and Drug Administration (FDA)-approved drug library consisting of 528 compounds. Benzethonium Chloride (BZN), a FDA-approved drug for anti-infective, was found to markedly induce apoptosis and inhibit proliferation and colony formation ability of lung cancer cells in dose- and time-dependent manners. BZN also enhanced the sensitivity of lung cancer cells to gefitinib, the first-line treatment strategy for selected lung cancer patients. Furthermore, BZN significantly delayed the growth of tumor xenografts in nude mice by increasing apoptosis and decreasing Ki-67 proliferation index, without obvious toxic effects to the vital organs of animals. Mechanistically, quantitative proteomics coupled with bioinformatics analyses and a series of functional assays demonstrated that BZN induced cell cycle arrest at G1 phase, and this was associated with an increase in p38-mediated phosphorylation at threonine 286 (T286) and accelerated degradation of cyclin D1. Our findings provide the first evidence that BZN could be a promising therapeutic agent in lung cancer treatment.

LncRNA FOXC2 antisense transcript accelerates non-small-cell lung cancer tumorigenesis via silencing p15

Non-coding RNAs (ncRNAs) have been demonstrated to modulate the oncogenesis of non-small cell lung cancer (NSCLC), especially the long non-coding RNAs (lncRNAs). However, the role of lncRNA FOXC2-AS1 in the NSCLC is still unclear. In this research, we find that lncRNA FOXC2-AS1 is involved to NSCLC oncogenesis. The ectopic high-expression level of FOXC2-AS1 is closely correlated with the limited NSCLC patients' survival. In the functional experiments, the knockdown of FOXC2-AS1 dramatically suppressed the NSCLC cells' (A549, H460) proliferation, accelerated the apoptosis and induced the cycle arrest at G0/G1 phase. Mechanistic experiments revealed that FOXC2-AS1 repressed the p15 expression via recruiting the polycomb repressive complex 2 (PRC2) to the promoter of p15. The interaction within FOXC2-AS1 and p15 was validated using the rescue experiments. In conclusion, the results in this work confirmed that FOXC2-AS1 could aggravate NSCLC oncogenesis through repressing p15 expression via interacting EZH2, which provide new idea for the NSCLC therapeutic strategy.

PinX1 represses renal cancer angiogenesis via the mir-125a-3p/VEGF signaling pathway

BACKGROUND

PIN2/TRF1-interacting telomerase inhibitor 1 (PinX1) is a tumor suppressor in various tumors. However, the molecular mechanism underlying PinX1's role in cancer development and progression remains unclear. In this study, we aimed to uncover the new molecular mechanism and role of PinX1 in renal cell carcinoma (RCC) progression.

METHODS

We used miRNA microarray to detect the different expressed miRNAs upon PinX1 knockdown. Chromatin immunoprecipitation and Luciferase reporter assays were taken to identify the molecular mechanism of PinX1 in regulating mir-125-3p. In situ hybridization was performed to analyze the expression of mir-125a-3p in RCC using tissue microarray. The correlations between the mir-125a-3p expression level and clinicopathological features were evaluated using the χ² test. The role and molecular mechanism of PinX1 in RCC angiogenesis were investigated through a series of in vitro and in vivo experiments.

RESULTS

In this study, we discovered a new molecular mechanism of PinX1, in which PinX1 transcriptionally activated mir-125a-3p expression, thereby inhibiting the expression of vascular endothelial growth factor (VEGF), which is the target gene of mir-125a-3p. PinX1 also repressed tumor angiogenesis by increasing the mir-125a-3p expression in renal cancer. Moreover, the loss of mir-125a-3p expression was manifested in patients with RCC, and low miR-125a-3p levels correlated with poor survival of these patients.

CONCLUSIONS

PinX1 represses renal cancer angiogenesis through mir-125a-3p/VEGF signal pathway. The miR-125a-3p may be a candidate clinical prognostic marker and a novel therapeutic target in RCC.

The PinX1/NPM interaction associates with hTERT in early-S phase and facilitates telomerase activation

Background

Telomere maintenance is an important factor in tumorigenesis. PinX1 is a potent telomerase regulator which also involves in telomerase loading to telomeres. Nucleophosmin (NPM) can partially attenuate PinX1 inhibition of telomerase activity and NPM loading to hTERT requires PinX1. However, the role of the PinX1/NPM interaction in telomerase activity is not fully understood.

Method

The long-term effects of PinX1 and NPM down-regulation on telomere length were investigated by TRF assay. The localization of the PinX1/NPM association and the NPM/PinX1/hTERT complex formation were examined by immunofluorescence studies.

Results

Concurrent long-term down-regulation of PinX1 and NPM led to a substantial decrease in telomere length. The interaction with PinX1 was crucial in NPM localization in the nucleolus during the S phase. PinX1 and NPM associated throughout S phase and the NPM/PinX1/hTERT complex formation peaked during the early-S phase. The PinX1/NPM interaction was shown to localize away from Cajal Bodies at the start of S phase.

Conclusion

PinX1/NPM interaction is important in telomerase regulation during catalysis. NPM is recruited to hTERT by PinX1 and is required in the proposed telomerase modulating unit to activate telomerase when telomere extension occurs during S phase.

Electronic supplementary material

The online version of this article (10.1186/s13578-019-0306-y) contains supplementary material, which is available to authorized users.

Insufficient PINX1 expression stimulates telomerase activation by direct inhibition of EBV LMP1-NF-κB axis during nasopharyngeal carcinoma development

OBJECTIVE

Early malignant transformation of nasopharyngeal carcinoma(NPC) is associated with Epstein-Barr virus(EBV) infection and telomerase activation. The EBV latent membrane protein 1(LMP1) regulates expression of various genes by triggering NF-κB signaling pathway. PINX1 is a well-identified tumor suppressor gene by inhibiting telomerase activity and cancer cell growth. However, whether and how EBV inhibit PINX1 expression and activate telomerase in NPC is still incompletely elucidated.

METHODS

Immunohistochemistry, real-time PCR and Western blotting were utilized to explore the expression of PINX1. Chromatin immunoprecipitation(ChIP) and Dual-luciferase reporter assay were used to elucidate the regulatory mechanism between NF-κB and PINX1. TRAP-SYBR Green assay and Southern blotting were utilized to detect telomerase activity and telomere length. CCK8 and EdU tests were conducted to measure proliferation ability.

RESULTS

We demonstrated that PINX1 is down-regulated in NPC for the first time. Mechanistically, we found that LMP1 could inhibit the transcriptional activity of PINX1 by promoting the binding of p65 to three specific sites in PINX1 promoter, significantly, two(-1698/-1689, tgcaatttcc; -206/-197, cgggctttac) of which have not been reported. In addition, we also observed that LMP1 overexpression resulted in increased telomerase activity, prolonged telomere length and enhanced proliferation.

CONCLUSION

We first discovered EBV led to reduced PINX1 expression through LMP1-NF-κB-PINX1 axis, which up-regulated telomerase activity in NPC. And hence, the tumor cells acquired the ability to proliferate more exuberantly. This signaling pathway illustrates the relationship between EBV latent infection and telomerase activation, and further provides new thinking for early diagnosis and treatment in NPC.

Acidic Microenvironment Up-Regulates Exosomal miR-21 and miR-10b in Early-Stage Hepatocellular Carcinoma to Promote Cancer Cell Proliferation and Metastasis

Rationale: The incidence of hepatocellular carcinoma is rising worldwide. It is predicted that nearly half of the early-stage hepatocellular carcinoma (E-HCC) patients will develop recurrence. Dysregulated pH, a hallmark of E-HCC, is correlated with poor prognosis. The acidic microenvironment has been shown to promote the release of exosomes, the membrane vesicles recognized as intercellular communicators associated with tumor progression, recurrence, and metastasis. We, therefore, aimed to identify exosomes induced by acidic microenvironment that may regulate E-HCC progression and to explore their mechanisms and clinical significance in E-HCCs.

Methods: miRNA microarray analysis and LASSO logistic statistic model were used to identify the main functional exosomal miRNAs. Invasion and scratch assays were performed to examine the migration and invasion of HCC cells. Immunoblotting and immunofluorescence were employed to detect the epithelial-to-mesenchymal transition (EMT) in HCC cells. Chromatin immunoprecipitation (ChIP) was used to analyze the binding of HIF-1α and HIF-2α to promoter regions of miR-21 and miR-10b.

Results: The acidic microenvironment in HCC was correlated with poor prognosis of patients. Exosomes from HCC cells cultured in the acidic medium could promote cell proliferation, migration, and invasion of recipient HCC cells. We identified miR-21 and miR-10b as the most important functional miRNAs in acidic HCC-derived exosomes. Also, the acidic microenvironment triggered the activation of HIF-1α and HIF-2α and stimulated exosomal miR-21 and miR-10b expression substantially promoting HCC cell proliferation, migration, and invasion both in vivo and in vitro. In E-HCC patients, serum exosomal miR-21 and miR-10b levels were associated with advanced tumor stage and HIF-1α and HIF-2α expression and were independent prognostic factors for disease-free survival of E-HCC patients. Most importantly, we developed a nano-drug to target exosomal miR-21 and/or miR-10b and examined its therapeutic effects against HCC in vivo.

Conclusion: Our findings suggested that the exosomal miR-21 and miR-10b induced by acidic microenvironment in HCC promote cancer cell proliferation and metastasis and may serve as prognostic molecular markers and therapeutic targets for HCC.

Prognostic and Clinicopathological Value of PINX1 in Various Human Tumors: A Meta-Analysis

PINX1 (Pin2/TRF1 interacting protein X1, an intrinsic telomerase inhibitor and putative tumor suppressor gene) may represent a novel prognostic tumor biomarker. However, the results of previous studies are inconsistent and the prognostic value of PINX1 remains controversial. Therefore, we conducted a meta-analysis to determine whether PINX1 expression is associated with overall survival (OS), disease-specific survival (DSS), disease-free survival (DFS), recurrence-free survival (RFS), and clinicopathological characteristics in patients with malignant tumors. A systematic search was performed in the PubMed, Web of Science, and Embase databases in April 2018. Quality assessment was performed according to the modified Newcastle-Ottawa Scale. Pooled odds ratios (ORs) and hazard ratios (HRs) with 95.0% confidence intervals (CIs) were calculated to determine the relationship between PINX1 expression and OS, DSS, DFS/RFS, and clinicopathological characteristics. Due to the heterogeneity across the included studies, subgroup and sensitivity analyses were performed. Fixed-effects models were used when the heterogeneity was not significant and random-effects models were used when the heterogeneity was significant. Fourteen studies of 16 cohorts including 2,624 patients were enrolled. Low PINX1 expression was associated with poor OS (HR: 1.51, 95.0% CI: 1.03-2.20; P = 0.035) and DFS/RFS (HR: 1.78, 95.0% CI: 1.28-2.47; P = 0.001) but not DSS (HR: 0.80, 95.0% CI: 0.38-1.67; P = 0.548). Low PINX1 expression was also associated with lymphatic invasion (OR: 2.23, 95.0% CI: 1.35-3.70; P = 0.002) and advanced tumor-node-metastasis stage (OR: 2.43, 95.0% CI: 1.29-4.57; P = 0.006). No significant associations were observed between low PINX1 expression and sex, depth of invasion, grade of differentiation, and distant metastasis. Low PINX1 expression was associated with poor OS and DFS/RFS and lymphatic invasion and advanced tumor-node-metastasis stage, suggesting that PINX1 expression may be a useful predictor of prognosis in patients with malignant tumors.

IL‑17 induces NSCLC A549 cell proliferation via the upregulation of HMGA1, resulting in an increased cyclin D1 expression

Non-small cell lung cancer (NSCLC) is considered to be an inflammation-associated carcinoma. Although interleukin‑17 (IL‑17) production contributes to the proliferation and growth of NSCLC, the mechanisms underlying IL‑17-induced NSCLC cell proliferation have not been fully elucidated. In the present study, by using ELISA and immunohistochemical analyses, we first found that the expression levels of IL‑17, IL‑17 receptor (IL‑17R), high-mobility group A1 (HMGA1) and cyclin D1 were elevated in the samples of patients with NSCLC. Subsequently, by RT-qPCR, western blot analysis and cell proliferation assay in vitro, we revealed that stimulation with recombinant human IL‑17 (namely IL‑17A) markedly induced the expression of HMGA1 and cyclin D1 in the A549 cells (a human lung adenocarcinoma cell line) and promoted cell proliferation. Furthermore, luciferase reporter and ChIP assays confirmed that upregulated HMGA1 directly bound to the cyclin D1 gene promoter and activated its transcription. Notably, the response element of HMGA1 binding to the cyclin D1 promoter was disclosed for the first time, at least to the best of our knowledge. Taken together, our findings indicate that the IL‑17/HMGA1/cyclin D1 axis plays an important role in NSCLC cell proliferation and may provide new insight into NSCLC pathogenesis and may thus aid in the development of novel therapeutic targets for NSCLC.

LncRNA BC032020 suppresses the survival of human pancreatic ductal adenocarcinoma cells by targeting ZNF451

This study examined the effects of long non‑coding RNA (lncRNA) BC032020 on the development of human pancreatic ductal adenocarcinoma (PDAC), and the potential molecular mechanisms responsible for these effects. The expression of BC032020 was assessed in 20 pairs of PDAC tumor tissues and adjacent normal tissues. The overexpression of BC032020 was enforced in the AsPC‑1 and PANC‑1 cells, and the effects on cell proliferation, cell cycle distribution, cell migration and apoptosis were determined. We also analyzed the functions of zinc finger protein 451 (ZNF451), which shares a gene sequence with two exons of BC032020 and a non‑coding region with another two exons, in PDAC cells. The AsPC‑1 and PANC‑1 cells that overexpressed BC032020 were used to establish a subcutaneous tumor xenograft model in order to examine the effects of BC032020 on tumor growth in vivo. The results revealed that the BC032020 levels in the PDAC tumor tissues were lower than those in the adjacent normal tissues, and ZNF451 expression inversely correlated with the BC032020 levels in the PDAC tumor tissues and cell lines. BC032020 overexpression led to a decrease in ZNF451 expression; it also suppressed the proliferation and migration of the AsPC‑1 and PANC‑1 cells, and induced G1 phase arrest and cell apoptosis. The results of in vivo experiments revealed that BC032020 suppressed tumor growth in a xenograft model by inhibiting ZNF451 expression. Taken together, the findings of this study indicate that BC032020 suppresses the survival of PDAC cells by inhibiting ZNF451 expression.