Pleomorphic adenoma gene 1 mediates the role of karyopherin alpha 2 and has prognostic significance in hepatocellular carcinoma

Novel roles of karyopherin subunit alpha 2 in hepatocellular carcinoma

Hepatocellular carcinoma is the most common type of liver cancer and associated with a high fatality rate. This disease poses a major threat to human health worldwide. A considerable number of genetic and epigenetic factors are involved in the development of hepatocellular carcinoma. However, the molecular mechanism underlying the progression of hepatocellular carcinoma remains unclear. Karyopherin subunit alpha 2 (KPNA2), also termed importin α1, is a member of the nuclear transporter family. In recent years, KPNA2 has been gradually linked to the nuclear transport pathway for a variety of tumor-associated proteins. Furthermore, it promotes tumor development by participating in various pathophysiological processes such as cell proliferation, apoptosis, immune response, and viral infection. In hepatocellular carcinoma, it has been found that KPNA2 expression is significantly higher in liver cancer tissues versus paracancerous tissues. Moreover, it has been identified as a marker of poor prognosis and early recurrence in patients with hepatocellular carcinoma. Nevertheless, the role of KPNA2 in the development of hepatocellular carcinoma remains to be determined. This review summarizes the current knowledge on the pathogenesis and role of KPNA2 in hepatocellular carcinoma, and provides new directions and strategies for the diagnosis, treatment, and prediction of prognosis of this disease.

IGFBP5 is Upregulated and Associated with Poor Prognosis in Colorectal Cancer

Purpose

This study aimed to investigate the role of IGFBP5 in colorectal cancer (CRC) and the relationship between the expression of IGFBP5 and clinicopathological parameters in CRC patients.

Patients and Methods

Immunohistochemical analysis was used to detect the expression of IGFBP5 and its correlation with clinicopathological parameters of CRC patients. Prognosis analysis, gene set enrichment analysis, and protein interaction network analysis were performed using bioinformatics analysis. The Genomics of Drug Sensitivity in Cancer (GDSC) dataset was used to analyze the correlation between the expression of IGFBP5 and drug resistance.

Results

Immunohistochemical analysis revealed that the expression of IGFBP5 was significantly higher in CRC tissues than in para-cancerous tissues (P < 0.05). High expression of IGFBP5 was associated with tumor differentiation and the N stage of CRC (P < 0.05). Moreover, high expression of IGFBP5 predicted worse overall survival and disease-free survival in CRC patients (P < 0.05). The expression of IGFBP5 was associated with cell–matrix adhesion, extracellular matrix binding, and collagen binding (P < 0.05). Furthermore, IGFBP5 was involved in the Hedgehog signaling pathway and PI3K-Akt signaling pathway (P < 0.05). IGF1, IGF2, SPP1, LTBP1, and FAM20C were most closely related to IGFBP5.

Conclusion

The expression of IGFBP5 is upregulated and associated with tumor differentiation, lymph node metastasis, drug resistance, and prognosis in CRC patients.

Overexpression of Karyopherin α2 in small cell carcinoma of the cervix correlates with poor prognosis

BACKGROUND

Cervical small cell carcinoma (SCCC) is uncommon and little is known about its molecular markers. Karyopherin α2 (KPNA2) has been demonstrated in a variety of malignancies. Our objective was to determine whether the KPNA2 level is predictive of clinical outcome in patients with SCCC.

METHODS

We detected KPNA2 expression by immunohistochemistry in SCCC tumors from 62 patients. The staining results were evaluated by H-score. The correlation among KPNA2 expression level, clinical characteristics, and prognosis was analyzed.

RESULTS

KPNA2 expression was detected in tumor tissue from 55 patients with SCCC (55/62, 89%). High KPNA2 expression correlated significantly with International Federation of Gynecology and Obstetrics staging (P=0.035), tumor size (P=0.019), poorer overall survival (OS) (P=0.008), and poorer disease-free survival (P=0.004) compared to low KPNA2 expression. Multivariate analysis showed that KPNA2 expression level (P=0.037) and tumor size (P=0.046) were independent prognostic factors of OS.

CONCLUSIONS

KPNA2 may be a molecular marker and indicator of prognosis in SCCC.

HIF-1α-activated long non-coding RNA KDM4A-AS1 promotes hepatocellular carcinoma progression via the miR-411-5p/KPNA2/AKT pathway

Hepatocellular carcinoma (HCC) is the most common type of liver cancer with poor clinical outcomes. Long non-coding RNAs (lncRNAs) are extensively involved in the tumorigenesis and progression of HCC. However, more investigations should be carried out on novel lncRNAs and their effects on HCC. Here we identified a novel lncRNA KDM4A-AS1, which was aberrantly overexpressed in HCC tissues, associated with unfavorable clinical features and poor prognosis of patients. KDM4A-AS1 promoted HCC cell proliferation, migration, and invasion in vitro and contributed to HCC growth and lung metastasis in vivo. Mechanistically, KDM4A-AS1 was inversely modulated by miR-411-5p at the post-transcriptional level and facilitated Karyopherin α2 (KPNA2) expression by competitively binding miR-411-5p, thereby activating the AKT pathway. KPNA2 silencing, miR-411-5p overexpression, and AKT inhibitor (MK2206) consistently reversed KDM4A-AS1-enhanced proliferation, mobility, and EMT of HCC cells. KDM4A-AS1 was identified as a novel hypoxia-responsive gene and transactivated by hypoxia-inducible factor 1α (HIF-1α) in HCC cells. In turn, KDM4A-AS1 regulated HIF-1α expression through the KPNA2/AKT signaling pathway. Hence, this study revealed a novel hypoxia-responsive lncRNA, KDM4A-AS1, which contributed to HCC growth and metastasis via the KDM4A-AS1/KPNA2/HIF-1α signaling loop. Our findings provide a promising prognostic and therapeutic target for HCC.

Multiomics-based analyses of KPNA2 highlight its multiple potentials in hepatocellular carcinoma

Dysregulation and prognostic roles of Karyopherin α2 (KPNA2) were reported in many malignancies including hepatocellular carcinoma (HCC). A multi-omics analysis of KPNA2 is needed to gain a deeper understanding of its multilevel molecular characteristics and provide novel clues for HCC diagnosis, prognosis, and target therapy. Herein multi-omic alterations of KPNA2 were analyzed at genetic, epigenetic, transcript, and protein levels with evaluation of their relevance with clinicopathological features of HCC by integrative analyses. The significant correlations of KPNA2 expression with its gene copy number variation (CNV) and methylation status were shown through Spearman correlation analyses. With Cox regression, Kaplan-Meier survival, and receiver operating characteristic (ROC) analyses, based on the factors of KPNA2 CNV, methylation, expression, and tumor stage, risk models for HCC overall survival (OS) and disease-free survival (DFS) were constructed which could discriminate the 1-year, 3-year, and 5-year OS/DFS status effectively. With Microenvironment Cell Populations-counter (MCP-counter), the immune infiltrations of HCC samples were evaluated and their associations with KPNA2 were shown. KPNA2 expression in liver was found to be influenced by low fat diet and presented significant correlations with fatty acid metabolism and fatty acid synthase activity in HCC. KPNA2 was detected lowered in HCC patient's plasma by enzyme linked immunosorbent assay (ELISA), consistent with its translocation to nuclei of HCC cells. In conclusion, KPNA2 multilevel dysregulation in HCC and its correlations with immune infiltration and the fatty acid metabolism pathway indicated its multiple roles in HCC. The clinicopathological significance of KPNA2 was highlighted through the in-depth analyses at multilevels.

Comprehensive analysis of the competing endogenous circRNA-lncRNA-miRNA-mRNA network and identification of a novel potential biomarker for hepatocellular carcinoma

BACKGROUND

The competing endogenous RNAs (ceRNAs) hypothesis has received increasing attention as a novel explanation for tumorigenesis and cancer progression. However, there is still a lack of comprehensive analysis of the circular RNA (circRNA)-long non-coding RNA (lncRNA)-miRNA-mRNA ceRNA network in hepatocellular carcinoma (HCC).

METHODS

RNA sequencing data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) database were employed to identify Differentially Expressed mRNAs (DEmRNAs), DElncRNAs, and DEcircRNAs between HCC and normal tissues. Candidates were identified to construct networks through a comprehensive bioinformatics strategy. A prognostic mRNA signature was established based on data from TCGA database and validated using data from the GEO database. Then, the HCC prognostic circRNA-lncRNA-miRNA-mRNA ceRNA network was established. Finally, the expression and function of an unexplored hub gene, deoxythymidylate kinase (DTYMK), was explored through data mining. The results were examined using clinical samples and in vitro experiments.

RESULTS

We constructed a prognostic signature with seven target mRNAs by univariate, lasso and multivariate Cox regression analyses, which yielded 1, 3 and 5-year AUC values of 0.797, 0.733 and 0.721, respectively, indicating its sensitivity and specificity in the prognosis of HCC. Moreover, the prognostic signature could be validated in GSE14520. The prognostic ceRNA network of 21 circRNAs, 15 lncRNAs, 5 miRNAs, and 7 mRNAs was established according to the targeting relationship between 7 hub mRNAs and other RNAs. Our experiment results indicated that the depletion of DTYMK inhibited liver cancer cell proliferation and invasion.

CONCLUSIONS

The network revealed in this study may help comprehensively elucidate the ceRNA mechanisms driving HCC, and provide novel candidate biomarkers for evaluating the prognosis of HCC.

KPNA2 interaction with CBX8 contributes to the development and progression of bladder cancer by mediating the PRDM1/c-FOS pathway

BACKGROUND

Bladder cancer (BCa) is a common malignancy characterized by high heterogeneity, yet the current treatment modalities are limited. The aim of the present investigation was to unravel the functional role of Karyopherin alpha 2 (KPNA2), a tumor facilitator identified in multiple malignancies, in the progression of BCa.

METHODS

BCa tissues and adjacent normal tissues were surgically resected and analyzed from patients with BCa to determine the expression profile of KPNA2 and Chromobox 8 (CBX8) by RT-qPCR, Western blot analysis and immunohistochemistry. The relationship among KPNA2, CBX8 and PR domain zinc finger protein 1 (PRDM1) was explored by co-immunoprecipitation and chromatin-immunoprecipitation. The functions of KPNA2, CBX8 and PRDM1 on BCa cell proliferation, migration and invasion were evaluated. Next, a nude mouse model of BCa was established for validating the roles of KPNA2, CBX8 and PRDM1 in vivo.

RESULTS

KPNA2 and CBX8 were highly expressed in BCa and are in association with dismal oncologic outcomes of patients with BCa. KPNA2 promoted nuclear import of CBX8. CBX8 downregulated PRDM1 by recruiting BCOR in the promoter region of PRDM1. Overexpression of KPNA2 promoted the malignant behaviors of BCa cells, which was counteracted by silencing of CBX8. Overexpressing PRDM1 attenuated the progression of BCa by inhibiting c-FOS expression. The tumor-promoting effects of KPNA2 via the PRDM1/c-FOS pathway were also validated in vivo.

CONCLUSION

Collectively, our findings attached great importance to the interplay between KPNA2 and CBX8 in BCa in mediating the development and progression of BCa, thus offering a promising candidate target for better BCa patient management.

PLAGL2-EGFR-HIF-1/2α Signaling Loop Promotes HCC Progression and Erlotinib Insensitivity

BACKGROUND AND AIMS

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide, hence a major public health threat. Pleomorphic adenoma gene like-2 (PLAGL2) has been reported to play a role in tumorigenesis. However, its precise function in HCC remains poorly understood.

APPROACH AND RESULTS

In this study, we demonstrated that PLAGL2 was up-regulated in HCC compared with that of adjacent nontumorous tissues and also correlated with overall survival times. We further showed that PLAGL2 promoted HCC cell proliferation, migration, and invasion both in vitro and in vivo. PLAGL2 expression was positively correlated with epidermal growth factor receptor (EGFR) expression. Mechanistically, this study demonstrated that PLAGL2 functions as a transcriptional regulator of EGFR and promotes HCC cell proliferation, migration, and invasion through the EGFR-AKT pathway. Moreover, hypoxia was found to significantly induce high expression of PLAGL2, which promoted hypoxia inducible factor 1/2 alpha subunit (HIF1/2A) expression through EGFR. Therefore, this study demonstrated that a PLAGL2-EGFR-HIF1/2A signaling loop promotes HCC progression. More importantly, PLAGL2 expression reduced hepatoma cells' response to the anti-EGFR drug erlotinib. PLAGL2 knockdown enhanced the response to erlotinib.

CONCLUSIONS

This study reveals the pivotal role of PLAGL2 in HCC cell proliferation, metastasis, and erlotinib insensitivity. This suggests that PLAGL2 can be a potential therapeutic target of HCC.

Karyopherin α 2 promotes proliferation, migration and invasion through activating NF-κB/p65 signaling pathways in melanoma cells

AIMS

Melanoma is a fatal malignancy. Karyopherin α 2 (KPNA2) plays an important role in many carcinogenesis. This study was aimed to study the role of KPNA2 in cellular functions and molecular mechanisms of melanoma.

MAIN METHODS

We investigated the expression and prognosis of KPNA2 in melanoma using the GEPIA database (http://gepia.cancer-pku.cn/). The effect of KPNA2 on melanoma cells was determined using real-time PCR, western blot, immunofluorescence assay, CCK-8, colony formation, wound healing assay, transwell assay, EMSA, and immunohistochemistry. The influence of KPNA2 on the tumorigenicity of melanoma cells was evaluated in a nude mice model in vivo.

KEY FINDINGS

Our results showed that KPNA2 expression is relatively high in melanoma tissues and cells, and melanoma patients with higher expression of KPNA2 had lower overall survival rate and disease free survival rate. KPNA2 promoted proliferation ability and increased the expression of PCNA, Ki67, and C-MYC in melanoma cells. Further, KPNA2 could promote migration and invasion and increase the expression of MMP2 and MMP9. Mechanism studies showed that KPNA2 activated NF-κB/p65 signaling pathways, as evidenced by the nuclear translocation of p65 and increased the expression of COX-2, ICAM-1, iNOS, and MCP1 in melanoma cells. NF-κB inhibitor JSH-23 could reverse the pro-tumor effects of KPNA2 on melanoma cells. Moreover, upregulation of KPNA2 facilitated the tumorigenicity of melanoma cells.

SIGNIFICANCE

KPNA2 promotes proliferation, migration and invasion through enhancing NF-κB/p65 signaling pathways in melanoma cells. Our study suggests KPNA2 as a potential therapeutic target for the treatment of melanoma.

PLAG1 silencing promotes cell chemosensitivity in ovarian cancer via the IGF2 signaling pathway

Ovarian cancer (OC) is one of the most lethal gynecological diseases. Novel prognostic biomarkers and therapeutic targets for OC are urgently required. The aim of this study was to investigate the mechanisms that govern how pleomorphic adenoma gene 1 (PLAG1) influences the biological processes and chemosensitivity of OC cells via the insulin‑like growth factor‑2 (IGF2) signaling pathway. Differentially expressed genes in OC were selected based on bioinformatics data. OC and adjacent tissue specimen were collected, followed by the determination of the expression of PLAG1 and IGF2 signaling pathway‑associated genes. The regulatory mechanisms of PLAG1 in OC cells were analyzed following treatment with pcDNA or small interfering RNA (siRNA), and included the assessment of cell proliferation, migration, invasion and cisplatin resistance. PLAG1 was identified as an upregulated gene in OC. OC tissues exhibited increased expression of PLAG1 and IGF2 compared with the controls. Moreover, PLAG1 was observed to positively regulate the IGF2 signaling pathway. The siRNA‑mediated silencing of PLAG1 resulted in decreased expression of IGF2, IGF1 receptor and insulin receptor substrate 1, as well as inhibited proliferation, migration, invasion and cisplatin resistance of OC cells. Furthermore, the effect of PLAG1 was dependent on IGF2. PLAG1 may therefore be considered as a possible target for the treatment of OC.

The emerging roles of KPNA2 in cancer

Karyopherin α2 (KPNA2, also known as importinα-1), a member of the nuclear transporter family, is involved in the nucleocytoplasmic transport pathway of a variety of tumor-associated proteins. Recent studies have found that KPNA2 is overexpressed in various cancers, which is associated with poor prognosis. In addition, it has been shown to promote tumor formation and progression by participating in cell differentiation, proliferation, apoptosis, immune response, and viral infection. It is indicated that KPNA2 also plays an important role in the diagnosis, treatment and prognosis of tumors. Herein, we provide an overview of the function and mechanism of KPNA2 in cancer and the prospects in the diagnosis and treatment of cancer. In the future, KPNA2 provides new ideas for the early diagnosis of malignant tumors, the development of molecularly targeted drugs, and prognosis evaluation.

Genome-wide screening diagnostic biomarkers and the construction of prognostic model of hepatocellular carcinoma

Although methods in diagnosis and therapy of hepatocellular carcinoma (HCC) have made significant progress in decades, the overall survival (OS) of HCC remains dissatisfactory, so it is particularly important to find better diagnostic and prognostic biomarkers. In this study, we found a more reliable potential diagnostic biomarkers and constructed a more accurate prognostic evaluation model based on integrated transcriptome sequencing analysis of multiple independent data sets. First, we performed quality evaluation and differential analysis on seven Gene Expression Omnibus (GEO) data sets, and then comprehensively analyzed the differentially expressed genes with a robust rank aggregation algorithm. Next, Least absolute shrinkage and selection operator (LASSO) regression was used to establish an 8-gene prognostic risk score (RS) model. Finally, the prognostic model was further validated in the GEO data set. Also, RS has independence on other clinicopathological characteristics but has similarities in prognostic assessment compared with the T stage. Moreover, the combination of T stage and prognostic RS model based on the 8-gene had a better prognostic evaluation effect. In brief, our research suggest that the prognostic risk model of 8 genes has important clinical significance in HCC patients, and can further enrich the prognostic guidance value of the traditional T stage.

Identification of key genes and long non-coding RNA associated ceRNA networks in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths worldwide. Although multiple efforts have been made to understand the development of HCC, morbidity, and mortality rates remain high. In this study, we aimed to discover the mRNAs and long non-coding RNAs (lncRNAs) that contribute to the progression of HCC. We constructed a lncRNA-related competitive endogenous RNA (ceRNA) network to elucidate the molecular regulatory mechanism underlying HCC.

Methods

A microarray dataset (GSE54238) containing information about both mRNAs and lncRNAs was downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) and lncRNAs (DElncRNAs) in tumor tissues and non-cancerous tissues were identified using the limma package of the R software. The miRNAs that are targeted by DElncRNAs were predicted using miRcode, while the target mRNAs of miRNAs were retrieved from miRDB, miRTarBas, and TargetScan. Functional annotation and pathway enrichment of DEGs were performed using the EnrichNet website. We constructed a protein–protein interaction (PPI) network of DEGs using STRING, and identified the hub genes using Cytoscape. Survival analysis of the hub genes and DElncRNAs was performed using the gene expression profiling interactive analysis database. The expression of molecules with prognostic values was validated on the UALCAN database. The hepatic expression of hub genes was examined using the Human Protein Atlas. The hub genes and DElncRNAs with prognostic values as well as the predictive miRNAs were selected to construct the ceRNA networks.

Results

We found that 10 hub genes (KPNA2, MCM7, CKS2, KIF23, HMGB2, ZWINT, E2F1, MCM4, H2AFX, and EZH2) and four lncRNAs (FAM182B, SNHG6, SNHG1, and SNHG3) with prognostic values were overexpressed in the hepatic tumor samples. We also constructed a network containing 10 lncRNA–miRNA–mRNA pathways, which might be responsible for regulating the biological mechanisms underlying HCC.

Conclusion

We found that the 10 significantly overexpressed hub genes and four lncRNAs were negatively correlated with the prognosis of HCC. Further, we suggest that lncRNA SNHG1 and the SNHG3-related ceRNAs can be potential research targets for exploring the molecular mechanisms of HCC.

E2F1 and E2F7 differentially regulate KPNA2 to promote the development of gallbladder cancer

Karyopherin alpha 2 (KPNA2) is a nuclear import factor that is elevated in multiple cancers. However, its molecular regulation at the transcriptional levels is poorly understood. Here we found that KPNA2 was significantly upregulated in gallbladder cancer (GBC), and the increased levels were correlated with short survival of patients. Gene knocking down of KPNA2 inhibited tumor cell proliferation and migration in vitro as well as xenografted tumor development in vivo. A typical transcription factor E2F1 associated with its DNA-binding partner DP1 bond to the promoter region of KPNA2 and induced KPNA2 expression. In contrast, an atypical transcription factor E2F7 competed against DP1 and blocked E2F1-induced KPNA2 gene activation. Mutation of the dimerization residues of E2F7 or DNA-binding domain of E2F1 abolished the suppressive effects of E2F7 on KPNA2 gene expression. In addition, KPNA2 mediated nuclear localization of E2F1 and E2F7, where they in turn controlled KPNA2 expression. Taken together, our data provided mechanistic insights into divergently transcriptional regulation of KPNA2, thus pointing to KPNA2 as a potential target for cancer therapy.

Prognostic value of increased KPNA2 expression in some solid tumors: A systematic review and meta-analysis

Background

Karyopherin α2 (KPNA2), a member of the Karyopherin α family, has recently been reported to play an important role in tumor progression. However, the association between KPNA2 expression and prognosis in cancer remains controversial. So we performed this meta-analysis to evaluate whether expression of KPNA2 was associated with prognosis in patients with solid tumor.

Methods/Findings

24 published eligible studies, including 6164 cases, were identified and included in this meta-analysis through searching of PubMed, EMBASE and Web of Science. We found that KPNA2 expression was an independent predictor for the prognosis of solid tumor with primary outcome (overall survival [OS]: pooled HR=1.767, 95% CI=1.503-2.077, P<0.001) and secondary outcomes (time to recurrence [TTR], recurrence free survival [RFS] and progression free survival [PFS]). However, the association between KPNA2 overexpression and disease free survival [DFS] in solid tumors was not significant (pooled HR=1.653, 95% CI=0.903-3.029, P=0.104). Furthermore, the subgroup analysis revealed that KPNA2 overexpression was associated with poor OS in East-Asian patients and European patients, as well as patients with gastric and colorectal cancer.

Conclusion

KPNA2 expression may be a useful prognostic biomarker to monitor cancer prognosis. Further prospective studies with larger sample sizes are required to confirm our findings.

Suppression of Kpnβ1 expression inhibits human breast cancer cell proliferation by abrogating nuclear transport of Her2

Breast cancer (BC) is one of the most fatal diseases and poses critical health problems worldwide. However, its mechanisms remain unclear. Consequently, there is an urgency to investigate the mechanisms involved in BC initiation and progression and identify novel therapeutics for its prevention and treatment. In this study, we identified karyopherin β-1 (Kpnβ1) as a possible novel therapeutic target for BC. Western blotting was used to evaluate the expression of Kpnβ1 in four pairs of tumorous and adjacent non-tumorous tissues. The results revealed that the protein level of Kpnβ1 was higher in the cancer samples compared with those in the corresponding normal samples. Immunohistochemistry was performed on 140 BC cases and indicated that Kpnβ1 was significantly associated with clinical pathological variables. Kaplan-Meier curve revealed that high expression of Kpnβ1 was related to poor BC patient prognosis. A starvation and re-feeding assay was used to imitate the cell cycle using the SKBR-3 cell line, indicating that Kpnβ1 plays a critical role in cell proliferation. The Cell Counting Kit-8 assay revealed that SKBR-3 cells treated with Kpnβ1-siRNA (siKpnβ1) grew more slowly than the control cells, while flow cytometry revealed that low-Kpnβ1 expressing SKBR-3 cells exhibited increased BC cell apoptosis. Furthermore, the interaction between Kpnβ1 and Her2 was clearly observed by immunoprecipitation, indicating that Kpnβ1-knockdown abrogated nuclear transport of Her2. In summary, our findings revealed that Kpnβ1 is involved in the progression of BC and may be a useful therapeutic target.

Silencing of karyopherin α2 inhibits cell growth and survival in human hepatocellular carcinoma

Karyopherin α2 (KPNA2), involved in nucleocytoplasmic transport, has been reported to be upregulated in hepatocellular carcinoma and considered as a biomarker for poor prognosis. However, comprehensive studies of KPNA2 functions in hepatocellular carcinogenesis are still lacking. Our study examine the roles and related molecular mechanisms of KPNA2 in hepatocellular carcinoma development. Results show that KPNA2 knockdown inhibited the proliferation and growth of hepatocellular carcinoma cells in vitro and in vivo. KPNA2 knockdown also inhibited colony formation ability, induced cell cycle arrest and cellular apoptosis in two hepatocellular carcinoma cell lines, HepG2 and SMMC-7721. Furthermore, gene expression microarray analysis in HepG2 cells with KPNA2 knockdown revealed that critical signaling pathways involved in cell proliferation and survival were deregulated. In conclusion, this study provided systematic evidence that KPNA2 was an essential factor promoting hepatocellular carcinoma and unraveled potential molecular pathways and networks underlying KPNA2-induced hepatocellular carcinogenesis.

Development of a pipeline for automated, high-throughput analysis of paraspeckle proteins reveals specific roles for importin α proteins

We developed a large-scale, unbiased analysis method to measure how functional variations in importin (IMP) α2, IMPα4 and IMPα6 each influence PSPC1 and SFPQ nuclear accumulation and their localization to paraspeckles. This addresses the hypothesis that individual IMP protein activities determine cargo nuclear access to influence cell fate outcomes. We previously demonstrated that modulating IMPα2 levels alters paraspeckle protein 1 (PSPC1) nuclear accumulation and affects its localization into a subnuclear domain that affects RNA metabolism and cell survival, the paraspeckle. An automated, high throughput, image analysis pipeline with customisable outputs was created using Imaris software coupled with Python and R scripts; this allowed non-subjective identification of nuclear foci, nuclei and cells. HeLa cells transfected to express exogenous full-length and transport-deficient IMPs were examined using SFPQ and PSPC1 as paraspeckle markers. Thousands of cells and >100,000 nuclear foci were analysed in samples with modulated IMPα functionality. This analysis scale enabled discrimination of significant differences between samples where paraspeckles inherently display broad biological variability. The relative abundance of paraspeckle cargo protein(s) and individual IMPs each influenced nuclear foci numbers and size. This method provides a generalizable high throughput analysis platform for investigating how regulated nuclear protein transport controls cellular activities.

Induction of immunogenic cell death by radiation-upregulated karyopherin alpha 2 in vitro

Accumulating evidence suggests the potential for radiation therapy to generate antitumor immune responses against tumor cells by inducing immunogenic cell death and phenotypic changes. We recently found that ionizing radiation upregulated karyopherin α2 (KPNA2) in HT-29 colorectal tumor cells using quantitative proteomic analysis. To determine whether this increased KPNA2 could function as a damage-associated molecular pattern to induce antitumor immune responses, mouse bone-marrow-derived dendritic cells (BMDCs) were treated with KPNA2. KPNA2 enhanced the surface expression of CD40, CD54, CD80, CD86, and MHC class I/II on BMDCs. DCs treated with KPNA2 exhibited increased secretion of pro-inflammatory cytokines such as IL-1β, IL-6, IL-12, IL-23, and TNF-α. Co-culture of CD4(+) T cells and KPNA2-treated DCs resulted in induction of Th1/17 cytokines (IFN-γ and IL-17) and reduction of TGF-β production. Moreover, KPNA2-treated DCs were capable of increasing granzyme B and perforin expression in cytotoxic T lymphocytes. These results demonstrated that radiation-induced dying colorectal cancer cells released considerable amounts of KPNA2 that induce the maturation and activation of DCs for synergistic antitumor effect of radiation.

Targeting nuclear transporters in cancer: Diagnostic, prognostic and therapeutic potential

The Karyopherin superfamily is a major class of soluble transport receptors consisting of both import and export proteins. The trafficking of proteins involved in transcription, cell signalling and cell cycle regulation among other functions across the nuclear membrane is essential for normal cellular functioning. However, in cancer cells, the altered expression or localization of nuclear transporters as well as the disruption of endogenous nuclear transport inhibitors are some ways in which the Karyopherin proteins are dysregulated. The value of nuclear transporters in the diagnosis, prognosis and treatment of cancer is currently being elucidated with recent studies highlighting their potential as biomarkers and therapeutic targets.

Karyopherin Alpha 2 Promotes the Inflammatory Response in Rat Pancreatic Acinar Cells Via Facilitating NF-κB Activation

BACKGROUND

Activation of the transcription factor NF-κB and expression of pro-inflammatory mediators have been considered as major events of acute pancreatitis (AP). Karyopherin alpha 2 (KPNA2), a member of the importin α family, reportedly modulates p65 subcellular localization.

AIM

This study aimed to investigate the expression and possible functions of KPNA2 in the AP cell and animal model, focusing on its association with NF-κB activation.

METHODS

An AP cell model was established with the cerulein-stimulated AR42J and isolated rat pancreatic acinar cells. The AP rat model was induced by the intraperitoneal injection of cerulein. The secretion of TNF-α, IL-6, and LDH was detected by ELISA kits and the production of NO using nitric oxide kit. Expression of KPNA2 was measured by RT-PCR and Western blot. Expression levels of IKKα, phosphorylation of p65, and total p65 were detected by Western blot. Co-localization of KPNA2 with p65 was observed by immunofluorescence assay. To determine the biological functions of KPNA2 in cerulein-induced inflammatory response, RNA interference was employed to knockdown KPNA2 expression in AR42J and isolated pancreatic acini cells.

RESULTS

Cerulein stimulated KPNA2 expression and IL-6, TNF-α, NO, and LDH production in rat pancreatic acinar cells. Cerulein triggered the phosphorylation and nuclear translocation of NF-κB p65 subunit, indicating the NF-κB activation. The co-localization and nuclear accumulation of KPNA2 and p65 were detected in cerulein-treated cells. Knocking down KPNA2 hindered cerulein-induced nuclear transportation of p65 and alleviated the subsequent inflammatory response in rat pancreatic acinar cells. Additionally, KPNA2 expression was significantly up-regulated in cerulein-induced AP rat model.

CONCLUSIONS

KPNA2-facilitated p65 nuclear translocation promotes NF-κB activation and inflammation in acute pancreatitis.

Karyopherin alpha 2 is a novel prognostic marker and a potential therapeutic target for colon cancer

Background

Karyopherin alpha 2 (KPNA2), a member of the karyopherin family, plays a vital role in carcinogenesis. Yet its role in colon cancer is poorly characterized. We sought to clarify the clinical significance of its dysregulated expression in human colon tumor specimens.

Methods

We evaluated KPNA2 mRNA and protein expression by real-time polymerase chain reaction and Western blotting in 40 primary colon cancer tissues and paired adjacent normal colon mucosa specimens. KPNA2 protein expression in colon tissue microarray of tumor and normal tissue specimens and lymph node metastasis specimens obtained from 195 colon cancer patients were analyzed immunohistochemically. The effect of KPNA2 knockdown on carcinogenesis potential of human colon cancer cells was determined using Cell Counting Kit-8 (CCK8), colony formation, cell migration, and tumorigenesis in nude mice.

Results

KPNA2 was expressed at higher levels in colon tumors and lymph node metastasis specimens than in normal tissues. Patients with KPNA2-positive tumors were significantly correlated with the American Joint Committee on Cancer (AJCC) stage (p = 0.01), T-classification (p = 0.018), regional lymph node metastasis (p = 0.025), distant metastasis (p = 0.014), and differentiated degree (p = 0.001). KPNA2 was shown to be an independent prognostic indicator of disease-free survival (HR 1.681; 95 % CI: 1.170–2.416; p = 0.005) and overall survival (HR 2.770; 95 % CI: 1.314–5.837; p = 0.007) for patients with colon cancer. Knockdown of KPNA2 expression inhibited colon cancer cell proliferation, colony formation, and migration.

Conclusion

KPNA2 might play an important role in colorectal carcinogenesis and functions as a novel prognostic indicator and a potential therapeutic target for colorectal cancer.

Anaplastic lymphoma kinase protein expression predicts micrometastases and prognosis for patients with hepatocellular carcinoma

The present study aimed to investigate anaplastic lymphoma kinase (ALK) status in hepatocellular carcinoma (HCC) and to evaluate whether abnormalities in expression were associated with patient prognosis. ALK status was investigated using immunohistochemistry (IHC), reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and fluorescence in situ hybridization (FISH) assays in 342 HCC patients. In addition, rapid amplification of complementary DNA ends-coupled PCR sequencing was performed, in order to confirm the presence of ALK abnormalities in patients exhibiting ALK messenger RNA (mRNA) overexpression. The correlation between ALK expression and the clinicopathological features and prognosis of the HCC patients was statistically analyzed. The results of the present study revealed overexpression of ALK protein and mRNA; furthermore, ALK gene copy number gains were observed via IHC (44.7%; 153/342), RT-qPCR (47.4%; 162/342) and FISH (32.7%; 112/342) analyses, although ALK rearrangement or mutation was not demonstrated in the results of any of these assays. ALK protein expression levels were significantly associated with hepatitis C virus (HCV) status (P<0.001) and the presence of micrometastases (P=0.011). Within the entire patient cohort, ALK expression was associated with poor progression-free survival (PFS; P=0.041). Subsequent analysis in patient subgroups that demonstrated hepatitis B surface antigen positivity, HCV negativity, stage III-IV disease, recurrence and micrometastasis positivity revealed that overall survival (OS) and PFS were significantly reduced in those patients exhibiting ALK expression compared with those patients who were negative for ALK expression. Multivariate analysis revealed that ALK expression was an independent risk factor for OS (P=0.042) and PFS (P=0.033), particularly for patients with stage III-IV tumors. Thus, ALK may serve as a novel indicator for the metastatic behavior and prognosis of HCC.

Genetic and epigenetic aspects of initiation and progression of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a primary cancer of the liver that is predominant in developing countries and is responsible for nearly 600000 deaths each year worldwide. Similar to many other tumors, the development of HCC must be understood as a multistep process involving the accumulation of genetic and epigenetic alterations in regulatory genes, leading to the activation of oncogenes and the inactivation or loss of tumor suppressor genes. Extensive research over the past decade has identified a number of molecular biomarkers, including aberrant expression of HCC-related genes and microRNAs. The challenge facing HCC research and clinical care at this time is to address the heterogeneity and complexity of these genetic and epigenetic alterations and to use this information to direct rational diagnosis and treatment strategies. The multikinase inhibitor sorafenib was the first molecularly targeted drug for HCC to show some extent of survival benefits in patients with advanced tumors. Although the results obtained using sorafenib support the importance of molecular therapies in the treatment of HCC, there is still room for improvement. In addition, no molecular markers for drug sensitivity, recurrence and prognosis are currently clinically available. In this review, we provide an overview of recently published articles addressing HCC-related genes and microRNAs to update what is currently known regarding genetic and epigenetic aspects of the pathogenesis of HCC and propose novel promising candidates for use as diagnostic and therapeutic targets in HCC.