KPNA2 is overexpressed in human and mouse endometrial cancers and promotes cellular proliferation

Integrated grade-wise profiling analysis reveals potential plasma miR-373-3p as prognostic indicator in Prostate Cancer & its target KPNA2

Background

Plasma microRNAs (miRNAs) have recently garnered attention for their potential as stable biomarkers in the context of Prostate Cancer (PCa), demonstrating established associations with tumor grade, biochemical recurrence (BCR), and metastasis. This study seeks to assess the utility of plasma miRNAs as prognostic indicators for distinguishing between high-grade and low-grade PCa, and to explore their involvement in PCa pathogenesis.

Methodology

We conducted miRNA profiling in both plasma and tissue specimens from patients with varying PCa grades. Subsequently, the identified miRNAs were validated in a substantial independent PCa cohort. Furthermore, we identified and confirmed the gene targets of these selected miRNAs through Western blot analysis.

Results

In our plasma profiling investigation, we identified 98, 132, and 154 differentially expressed miRNAs (DEMs) in high-grade PCa vs. benign prostatic hyperplasia (BPH), low-grade PCa vs. BPH, and high-grade PCa vs. low-grade PCa, respectively. Our tissue profiling study revealed 111, 132, and 257 statistically significant DEMs for the same comparisons. Notably, miR-373-3p emerged as the sole consistently dysregulated miRNA in both plasma and tissue samples of PCa. This miRNA displayed significant overexpression in plasma and tissue samples, with fold changes of 3.584 ± 0.5638 and 8.796 ± 1.245, respectively. Furthermore, we observed a significant reduction in KPNA2 protein expression in PCa.

Conclusion

Our findings lend support to the potential of plasma miR-373-3p as a valuable biomarker for predicting and diagnosing PCa. Additionally, this miRNA may contribute to the progression of PCa by inhibiting KPNA2 expression, shedding light on its role in the disease.

Value of KPNA4 as a diagnostic and prognostic biomarker for hepatocellular carcinoma

It is important to identify novel biomarkers to improve hepatocellular carcinoma (HCC) diagnosis and treatment. Herein, we reported the role of karyopherin α4 (KPNA4) in HCC patients through public data mining and examined the results using clinical samples in our center. Our results revealed that KPNA4 expression level was positively correlated with the infiltration of CD8⁺ T cells, B cells, dendritic cells, CD4⁺ T cells, neutrophils and macrophages. In addition, KPNA4 expression was significantly associated with T cell exhaustion. KPNA4 mRNA and protein expression levels were significantly higher in cancerous tissue than in normal tissue. Besides, the increased expression of KPNA4 indicated poor overall survival. Univariate and multivariate Cox regression analyses showed KPNA4 could be viewed as an independent risk factor for HCC patients. Moreover, our experimental results were consistent with those obtained from bioinformatic results. These findings revealed KPNA4 may serve as a novel prognostic biomarker and a potential therapeutic target for HCC.

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.

Prognostic molecular biomarkers in endometrial cancer: A review

Background:

Endometrial cancer (EC) is the fourth most common malignancy in women worldwide and the most common gynecological cancer in developed countries. The endometrioid subtype has an excellent prognosis with conventional treatment; however, recurrence reduces overall survival.

Objective:

Describe the most relevant evidence regarding selected potential molecular biomarkers that may predict overall survival (OS), relapse-free survival (RFS), and cancer-specific survival (CSS) in EC.

Methods:

An exhaustive search was performed in PUBMED with the search terms endometrial cancer, molecular biomarker, and survival. We selected original articles written in English about endometrial cancer, molecular biomarkers, and that included survival analysis published between January 2000 and December 2016.

Results:

Several molecular prognostic biomarkers have been studied in terms of survival and therapeutic response in women with endometrial cancer; hormone receptors, microRNAs, and other molecules have emerged as potentially useful biomarkers, including HER2, p21, HE4, PTEN, p27, ANCCA, and ANXA2.

Conclusions:

The use of biomarkers in the assessment of OS, RFS, and CSS requires large trials to expand our understanding of endometrial carcinogenesis. Several molecular markers are significantly associated with a high tumor grade and advanced clinical stage in EC and, therefore, could have additive effects when combined.

Wip1 cooperates with KPNA2 to modulate the cell proliferation and migration of colorectal cancer via a p53-dependent manner

Due to the increasing incidence and mortality, the early diagnosis, specific targeted therapies, and prognosis for colorectal cancer (CRC) attract more and more attention. Wild-type p53-induced phosphatase 1 (Wip1) and karyopherin α2 (KPNA2) have been regarded as oncogenes in many cancers, including CRC. Wip1 dephosphorylates p53 to inactivate it. TP53 activator and Wip1 inhibitor downregulate KPNA2 expression. Therefore, we speculate that Wip1 may co-operate with KPNA2 to modulate CRC progression in a p53-dependent manner. Here, Wip1 and KPNA2 messenger RNA expression and protein levels are significantly increased in CRC tissues and cell lines and are positively correlated with each other. Wip1 silence increases p53 phosphorylation while decreases KPNA2 protein. Wip1 knockdown remarkably suppresses CRC cell proliferation and migration while KPNA2 overexpression exerts an opposing effect. KPNA2 overexpression could partially rescue Wip1 silence-inhibited CRC cell proliferation and migration. Finally, Wip1 interacts with KPNA2 to modulate the activation of AKT/GSK-3β signaling and metastasis-related factors. In summary, Wip1 could co-operate with KPNA2 to modulate CRC cell proliferation and migration, possibly via a p53-dependent manner, through downstream AKT/GSK-3β pathway. We provided a novel mechanism of Wip1 interacting with KPNA2, therefore modulating CRC cell proliferation and migration.

MicroRNA-139 inhibits hepatocellular carcinoma cell growth through down-regulating karyopherin alpha 2

BACKGROUND

MicroRNA-139-5p (miR-139) has been shown to play important roles in hepatocellular carcinoma (HCC) development. However, the exact mechanism of miR-139 in HCC remains largely unknown.

METHODS

We investigated the function in human cell lines and patient tissue samples by experimental techniques in molecular biology including Co-IP assay, cell viability assay, quantitative real-time-PCR, et al. In addition, datasets were used to verify the results by database analysis. Statistical analysis was performed by using the GraphPad Prism 6 (GraphPad Software Inc., USA). A P value < 0.05 was defined as statistically significant.

RESULTS

In this study, we found that miR-139 was significantly down-regulated in HCC. MiR-139 level was negatively associated with the stage of HCC, and HCC patients with higher miR-139 level had longer overall survival (OS) than these having lower miR-139 expression. Overexpression of miR-139 led to reduced cell viability, elevated apoptosis, and decreased colony forming, migratory and invasive capacities in HCC cells, while down-regulation of miR-139 led to opposite phenotypes. MiR-139 also inhibited HCC growth in a xenograft mouse model. We identified karyopherin alpha 2 (KPNA2) as a direct target of miR-139. KPNA2 is up-regulated in HCC and higher KPNA2 level is associated with poor patient prognosis. Silencing of KPNA2 expression led to similar phenotypic changes as miR-139 overexpression. Restoration of KPNA2 attenuated the suppressive effects of miR-139 overexpression on cell viability, apoptosis, colony formation, migration and invasion. In addition, miR-139 overexpression and KPNA2 depletion led to decreased nucleus level of POU class 5 homeobox 1 (POU5F1) and c-myc, two well-known pro-oncogenes.

CONCLUSION

In together, these data revealed the essential roles of the miR-139/KPNA2 axis in HCC.

KPNA2 promotes metabolic reprogramming in glioblastomas by regulation of c-myc

Background

Cancer cells maintain energy metabolism mainly by glycolysis, even under sufficient oxygen conditions. It gives cancer cells better growth advantages under complicated internal environment. KPNA2 is a novel oncogene that has received much attention in recent years, but the exact mechanisms of KPNA2 in tumorigenesis and progression are largely unknown. Especially its potential roles in the metabolic transformation of tumors still remain to be explored.

Methods

The expressions of KPNA2 in glioblastoma and normal human brain samples were analyzed by immunohistochemical analysis. The activities of key enzymes in glycolysis, the production of lactate acid and glucose uptake were investigated by colorimetry. GLUT-1 expression was measured by flow cytometry. CCK8 was used to examine the cell viability in vitro, and the xenograft models in nude mice were established to explore the roles of KPNA2 in vivo. In addition, Co-IP, subcellular fractionation, western blot, immunofluorescence and luciferase assay were used to investigate the internal connection between KPNA2, c-myc and E2F1.

Results

In the present study, we found that KPNA2 was highly expressed in the glioma compared to the normal brain tissues. Level of KPNA2 was an independent predictor of prognosis in the glioma patients. Knockdown of KPNA2 in the glioblastoma cell lines U87 and U251 decreased deoxyglucose uptake, activities of the key glycolytic enzymes and lactate production. The level of oxidative phosphorylation (OXPHOS) was moderately decreased. Additioanlly, tumor proliferation and invasiveness were concomitantly downregulated. We have identified c-myc as a potential mediator of KPNA2. Aberrant expression of KPNA2 significantly changed the subcellular distribution of c-myc as well as its expression level. E2F1, another key cargo protein of KPNA2, was further identified to play a potential role in regulating the transcription of c-myc by KPNA2.

Conclusions

Our findings suggested that KPNA2, a potential tumor oncogene, performs its function in part via regulating cellular metabolism through c-myc signaling axis. It would provide a possible explanation for Warburg effect and thus offer a new perspective to the roles of KPNA2 in gliomagenesis.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0861-9) contains supplementary material, which is available to authorized users.

Depletion of nuclear import protein karyopherin alpha 7 (KPNA7) induces mitotic defects and deformation of nuclei in cancer cells

Background

Nucleocytoplasmic transport is a tightly regulated process carried out by specific transport machinery, the defects of which may lead to a number of diseases including cancer. Karyopherin alpha 7 (KPNA7), the newest member of the karyopherin alpha nuclear importer family, is expressed at a high level during embryogenesis, reduced to very low or absent levels in most adult tissues but re-expressed in cancer cells.

Methods

We used siRNA-based knock-down of KPNA7 in cancer cell lines, followed by functional assays (proliferation and cell cycle) and immunofluorescent stainings to determine the role of KPNA7 in regulation of cancer cell growth, proper mitosis and nuclear morphology.

Results

In the present study, we show that the silencing of KPNA7 results in a dramatic reduction in pancreatic and breast cancer cell growth, irrespective of the endogenous KPNA7 expression level. This growth inhibition is accompanied by a decrease in the fraction of S-phase cells as well as aberrant number of centrosomes and severe distortion of the mitotic spindles. In addition, KPNA7 depletion leads to reorganization of lamin A/C and B1, the main nuclear lamina proteins, and drastic alterations in nuclear morphology with lobulated and elongated nuclei.

Conclusions

Taken together, our data provide new important evidence on the contribution of KPNA7 to the regulation of cancer cell growth and the maintenance of nuclear envelope environment, and thus deepens our understanding on the impact of nuclear transfer proteins in cancer pathogenesis.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4261-5) contains supplementary material, which is available to authorized users.

Salidroside induces apoptosis in human ovarian cancer SKOV3 and A2780 cells through the p53 signaling pathway

Salidroside is one of the most potent compounds extracted from the plant Rhodiola rosea, and its cardiovascular protective effects have been studied extensively. However, the role of salidroside in human ovarian carcinoma remains unknown. The aim of the current study was to investigate the effects of salidroside on the proliferation and apoptosis of SKOV3 and A2780 cells using MTT assay and acridine orange/ethidium bromide staining. Salidroside activated caspase-3 and upregulated the levels of apoptosis-inducing factor, Bcl-2-associated X and Bcl-2-associated death promoter (Bad) proteins. Furthermore, salidroside downregulated the levels of Bcl-2, p-Bad and X-linked inhibitor of apoptosis proteins. Salidroside activated the caspase-dependent pathway in SKOV3 and A2780 cells, upregulating p53, p21^Cip1/Waf1 and p16^INK4a. These results suggest that the p53/p21^Cip1/Waf1/p16^INK4a pathway may serve a key function in salidroside-mediated effects on SKOV3 and A2780 cells. The current findings indicate that salidroside may be a promising novel drug candidate for ovarian 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.

Karyopherins in cancer

Malfunction of nuclear-cytoplasmic transport contributes to many diseases including cancer. Defective nuclear transport leads to changes in both the physiological levels and temporal-spatial location of tumor suppressors, proto-oncogenes and other macromolecules that in turn affect the tumorigenesis process and drug sensitivity of cancer cells. In addition to their nuclear transport functions in interphase, Karyopherin nuclear transport receptors also have important roles in mitosis and chromosomal integrity. Therefore, alterations in the expressions or regular functions of Karyopherins may have substantial effects on the course and outcome of diseases.

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.

Detection of CCNE1/URI (19q12) amplification by in situ hybridisation is common in high grade and type II endometrial cancer

One TCGA subgroup of endometrial cancer (EC) is characterised by extensive genomic DNA copy number alterations. CCNE1 located at 19q12 is frequently amplified in EC and a target for anti-cancer therapy. The relevance of URI, also located at 19q12, is unknown. To evaluate the prevalence of 19q12 (CCNE1/URI) in EC, we investigated different histologic types by in situ hybridisation (ISH) and copy number assay. We applied a previously established 19q12 ISH for the detection of CCNE1/URI copy numbers in EC (n = 270) using conventional bright field microscopy. In a subset (n = 21), 19q12 amplification status was validated by OncoScan assay. Manual ISH was controlled by a recently developed computational ISHProfiler algorithm. Associations of 19q12 status with Cyclin E1, URI and p53 expression, and clinico-pathological parameters were tested.

Amplification of 19q12 (CCNE1/URI) was found in 10.4% (28/270) and was significantly associated with type II EC (high grade and non-endometrioid; p < 0.0001), advanced FIGO stage (p = 0.001), high Cyclin E1 expression (p = 0.008) and aberrant p53 expression (p = 0.04). 19q12 ISH data were confirmed by OncoScan and computational ISHProfiler techniques. The 19q12 in situ hybridisation is a feasible and robust biomarker assay in molecular pathology. Amplification of CCNE1/URI predominantly occurred in type II endometrial cancer. Prospective clinical trials are warranted to assess the utility of combined 19q12 amplification and Cyclin E1/URI protein expression analysis for the prediction of therapeutic response to chemotherapy and/or cyclin-dependent kinase inhibitors in patients with endometrial cancer.

Overexpression of karyopherin-α2 in cholangiocarcinoma correlates with poor prognosis and gemcitabine sensitivity via nuclear translocation of DNA repair proteins

Cholangiocarcinoma is a highly malignant tumor, and the development of new therapeutic strategies is critical. Karyopherin-α2 (KPNA2) functions as an adaptor that mediates nucleocytoplasmic transport. Specifically, KPNA2 transports one of the important DNA repair machineries, the MRE11-RAD50-NBS1 (MRN) complex, to the nucleus. In this study, we clarified the significance of KPNA2 in cholangiocarcinoma. KPNA2 expression evaluated by immunohistochemical analysis was common in malignant tissue but rare in adjacent noncancerous tissues. KPNA2 overexpression was significantly correlated with poor prognosis and was an independent prognostic factor after surgery. In patients with cholangiocarcinoma who received gemcitabine after surgery, KPNA2 overexpression tended to be a prognostic indicator of poor overall survival. In KPNA2-depleted cholangiocarcinoma cells, proliferation was significantly decreased and gemcitabine sensitivity was enhanced in vitro and in vivo. Expression of KPNA2 and the MRN complex displayed colocalization in the nucleus. In addition, nuclear localization of the MRN complex was regulated by KPNA2 in vitro. These results suggest that KPNA2 expression may be a useful prognostic and predictive marker of gemcitabine sensitivity and survival. The regulation of KPNA2 expression may be a new therapeutic strategy for cholangiocarcinoma.

Inhibition of KPNA4 attenuates prostate cancer metastasis

Prostate cancer (PCa) is a common cancer in men. Although current treatments effectively palliate symptoms and prolong life, the metastatic PCa remains incurable. It is important to find biomarkers and targets to improve metastatic PCa diagnosis and treatment. Here we report a novel correlation between karyopherin α4 (KPNA4) and PCa pathological stages. KPNA4 mediates the cytoplasm-to-nucleus translocation of transcription factors, including nuclear factor kappa B, although its role in PCa was largely unknown. We find that knockdown of KPNA4 reduces cell migration in multiple PCa cell lines, suggesting a role of KPNA4 in PCa progression. Indeed, stable knockdown of KPNA4 significantly reduces PCa invasion and distant metastasis in mouse models. Functionally, KPNA4 alters tumor microenvironment in terms of macrophage polarization and osteoclastogenesis by modulating tumor necrosis factor (TNF)-α and -β. Further, KPNA4 is proved as a direct target of miR-708, a tumor-suppressive microRNA. We disclose the role of miR-708-KPNA4-TNF axes in PCa metastasis and KPNA4's potential as a novel biomarker for PCa metastasis.

Image-based computational quantification and visualization of genetic alterations and tumour heterogeneity

Recent large-scale genome analyses of human tissue samples have uncovered a high degree of genetic alterations and tumour heterogeneity in most tumour entities, independent of morphological phenotypes and histopathological characteristics. Assessment of genetic copy-number variation (CNV) and tumour heterogeneity by fluorescence in situ hybridization (ISH) provides additional tissue morphology at single-cell resolution, but it is labour intensive with limited throughput and high inter-observer variability. We present an integrative method combining bright-field dual-colour chromogenic and silver ISH assays with an image-based computational workflow (ISHProfiler), for accurate detection of molecular signals, high-throughput evaluation of CNV, expressive visualization of multi-level heterogeneity (cellular, inter- and intra-tumour heterogeneity), and objective quantification of heterogeneous genetic deletions (PTEN) and amplifications (19q12, HER2) in diverse human tumours (prostate, endometrial, ovarian and gastric), using various tissue sizes and different scanners, with unprecedented throughput and reproducibility.

Population analysis of microsatellite genotypes reveals a signature associated with ovarian cancer

Ovarian cancer (OV) ranks fifth in cancer deaths among women, yet there remain few informative biomarkers for this disease. Microsatellites are repetitive genomic regions which we hypothesize could be a source of novel biomarkers for OV and have traditionally been under-appreciated relative to Single Nucleotide Polymorphisms (SNPs). In this study, we explore microsatellite variation as a potential novel source of genomic variation associated with OV. Exomes from 305 OV patient germline samples and 54 tumors, sequenced as part of The Cancer Genome Atlas, were analyzed for microsatellite variation and compared to healthy females sequenced as part of the 1,000 Genomes Project. We identified a subset of 60 microsatellite loci with genotypes that varied significantly between the OV and healthy female populations. Using these loci as a signature set, we classified germline genomes as ‘at risk’ for OV with a sensitivity of 90.1% and a specificity of 87.6%. Cross-analysis with a similar set of breast cancer associated loci identified individuals ‘at risk’ for both diseases. This study revealed a genotype-based microsatellite signature present in the germlines of individuals diagnosed with OV, and provides the basis for a potential novel risk assessment diagnostic for OV and new personal genomics targets in tumors.

High expression of KPNA2 defines poor prognosis in patients with upper tract urothelial carcinoma treated with radical nephroureterectomy

BACKGROUND

To analyze the expression of karyopherin alpha 2 (KPNA2) in upper tract urothelial carcinoma (UTUC) and to investigate whether the KPNA2 expression provides additional prognostic information following radical nephroureterectomy (RNU).

METHODS

A tissue microarray (TMA) containing samples from 176 patients with UTUC who underwent RNU at our institute was analyzed for KPNA2 expression using immunohistochemistry. KPNA2 expression in normal urothelial cell line and urothelial carcinoma cell lines was evaluated by western blot analysis. Using RNA interference in vitro, the effects of KPNA2 inhibition on cellular viability, migration and apoptosis were determined.

RESULTS

KPNA2 expression was significantly upregulated in the UTUC samples compared with the adjacent normal urothelial tissues. High KPNA2 immunoreactivity was identified as a predictor of bladder recurrence (hazard ratio [HR]: 2.017, 95% CI 1.13-3.61, p = 0.018), poor disease-free survival (DFS, HR: 2.754, 95% CI 1.68-4.51, p = 0.001) and poor overall survival (OS, HR: 4.480, 95% CI 1.84-10.89, p = 0.001) for patients with UTUC after RNU. Furthermore, high KPNA2 immunoreactivity was independent of the conventional predictive factors in a multivariate analysis. Additional in vitro experiments revealed that KPNA2 expression was higher in urothelial carcinoma cell lines than in normal urothelial cell line. KPNA2 inhibition with a specific siRNA decreased cell viability and migration and increased apoptosis in urothelial carcinoma cell lines.

CONCLUSIONS

KPNA2 is a novel independent prognostic marker for bladder recurrence, DFS and OS of UTUC patients who have undergone RNU. Moreover, these data suggest that KPNA2 may be a promising therapeutic target for UTUC.