PAK1 Research Articles

The effect of microRNA-224 on the anti-apoptosis and proliferation promoting of cholangiocarcinoma cells in vitro

Objective To explore the regulatory mechanism of microRNA-224 (miR-224) in the apoptosis and proliferation of human cholangiocarcinoma (CC) cells and examine whether the pathway of miR-224-HOXD10-PAK4 exist in cc cells or not. Methods The expression of miR-224 in CC and adjacent normal tissue were measured by RT-PCR. QBC939 cells were chosen and divided into two groups: cell groups transducted with negative control viruses (NC group) and cell groups transducted with target gene miRNA-down virus (DOMN group). The rate of apoptosis and the number of colonies formed in QBC939 cell lines of DOWN group and NC group were counted. The expression of miR-224, API5, PAK4 and HOXD10 in QBC939 cell lines of DOWN group and NC group were measured by RT-PCR and western blotting. Results (1) MiR-224 expression was higher in CC tissues than that in normal bile duct tissues (P<0.05). (2) In QBC939 cells lines, miR-224 expression was lower in DOMN group than that in NC group. The clone formation of QBC939 cells in DOWN group was significantly lower than that of NC group. The apoptosis rate of QBC939 cells of DOWN group was significantly higher than that of NC group. (3)The expression of API5 and HOXD10 in QBC939 cells of DOWN group was significantly higher than that of NC group in the RT-PCR and western blotting experiments. (4) The expression of PAK4 in QBC939 cells of DOWN group was significantly lower than that of NC group in the RT-PCR and western blotting. Conclusions MiR-224 has anti-apoptotic effects and can promote the proliferation of QBC939 cells and may serve as an important regulator of QBC939 cell proliferation in vitro. There are miR-224-HOXD10-PAK4 signaling pathways in cholangiocarcinoma. Key words: Cholangiocarcinoma; microRNA-224 (miR-224); Cell apoptosis; Proliferation; Signal transduction, API5P1, PAK4, HOXD10

Inhibitory effect of JQ1 on proliferation of acute myeloid leukemia U937 cell line and its effect on the signal transduction pathway of STAT-5

Objective To study the suppressive mechanism of the bromo structural domain inhibitor JQ1 on the acute myeloid leukemia cell line U937 and its regulation of the STAT-5 signaling pathway. Methods U937 cells in the logarithmic growth phase were tested. Each experimental group was fed with 0.2, 1.0 and 4.0 μmol/L of JQ1, and a blank control group without JQ1 was set up. U937 cells were cultured for 48 h, and the cell proliferation inhibitory rate was measured by MTT assay. Flow cytometry (FCM) was used to detect the apoptotic rate. Real-time fluorescence quantitative polymerase chain reaction (RT-PCR) was used to detect the mRNA expression of focal adhesion kinase (FAK) and P21 activated kinase (PAK1). The expression of STAT-5 protein was analyzed by Western blot. Results Different concentration of JQ1 could inhibit the proliferation of U937 cells in a time and dose-dependent manner, and different concentration of JQ1 could induce the apoptosis of U937 cells in a dose-dependent manner. Treatment of U937 cells with different concentrations of JQ1 (0.2, 1.0 and 4.0 μmol/L) reduced the expression of FKA mRNA and PAK1 mRNA after 48 h, the expression of FAK mRNA was 0.417±0.066, 0.140±0.026, and 0.027±0.006 (F = 454.651, P = 0.000), and the expression of PAK1 mRNA was 0.533±0.045, 0.080±0.010, and 0.010±0.001 (F = 2 434.610, P = 0.000), and STAT-5 protein expression was also significantly inhibited. The expression of STAT-5 protein in U937 cells after treated with different concentrations of JQ1 (0.2, 1.0 and 4.0 μmol/L) for 48 h were 0.71±0.19, 0.62±0.16, 0.53±0.14, and 1.00±0.21 in the control group (F = 263.135, P = 0.000). Conclusion JQ1 can effectively inhibit the proliferation of the acute myeloid leukemia cell line U937 cells and induce their apoptosis, and the possible mechanism of action is regulated via STAT-5 signaling pathway. Key words: Leukemia, myeloid, acute; Cell line, U937; JQ1; STAT-5

Effect of PAK1 gene silencing on proliferation and apoptosis in hepatocellular carcinoma cell lines MHCC97-H and HepG2 and cells in xenograft tumor.

This study intends to explore the effect of the PAK1 gene silencing on apoptosis and proliferation of hepatocellular carcinoma (HCC) MHCC97-H and HepG2 cells and cells in xenograft tumor. MHCC97-H and HepG2 cells and mice with xenograft tumor in vivo were randomly divided into control, empty vector and PAK1 shRNA groups. Morphology and the expression of green fluorescent protein of MHCC97-H and HepG2 cells and cells in xenograft tumor were observed. MTT assay and flow cytometry were used to detect proliferation, cell cycle and apoptosis of MHCC97-H and HepG2 cells and cells in xenograft tumor. The expressions of PAK1, PCNA, Ki67, Cyclin E, CDK2, p21, p53, Bax and Bcl-2 were measured using the quantitative reverse transcription polymerase chain reaction and western blotting. Compared with the control and empty vector groups, number of adherent cells of MHCC97-H and HepG2 cells and cells in xenograft tumor was reduced, and green fluorescent cells became round and reduced in the PAK1 shRNA group. Cell proliferation, the cells at S phase, the mRNA and protein expressions of PAK1, PCNA, Ki67, Cyclin E, CDK2 and Bcl-2 of MHCC97-H and HepG2 cells and cells in xenograft tumor were decreased, while the cells at G1 phase, apoptosis rate, the mRNA and protein expressions of p21, p53 and Bax of MHCC97-H and HepG2 cells and cells in xenograft tumor were increased in the PAK1 shRNA group. PAK1 gene silencing decreases proliferation of MHCC97-H cells, HepG2 cells and cells in xenograft tumor through the p53/p21 pathway.

Backbone 1H, 15N, 13C assignment of Human Myc, N353 to A399, phosphorylated by PAK2

Backbone 1H, 15N, 13C assignment of Human Myc, N353 to A399, phosphorylated by PAK2

The Role of PAK2 in Tumor Progression

The Role of PAK2 in Tumor Progression

DNA methylation of a novel PAK4 locus influences ototoxicity susceptibility following cisplatin and radiation therapy for pediatric embryonal tumors

Ototoxicity is a common adverse side effect of platinum chemotherapy and cranial radiation therapy; however, individual susceptibility is highly variable. Therefore, our objective was to conduct an epigenome-wide association study to identify differentially methylated cytosine-phosphate-guanine (CpG) sites associated with ototoxicity susceptibility among cisplatin-treated pediatric patients with embryonal tumors. Samples were collected for a discovery cohort (n = 62) and a replication cohort (n = 18) of medulloblastoma and primitive neuroectodermal tumor patients. Posttreatment audiograms were evaluated using the International Society of Paediatric Oncology (SIOP) Boston Ototoxicity Scale. Genome-wide associations between CpG methylation and ototoxicity were examined using multiple linear regression, controlling for demographic and treatment factors. The mean cumulative dose of cisplatin was 330 mg/m2 and the mean time from end of therapy to the last available audiogram was 6.9 years. In the discovery analysis of 435233 CpG sites, 6 sites were associated with ototoxicity grade (P < 5 × 10-5) after adjusting for confounders. Differential methylation at the top CpG site identified in the discovery cohort (cg14010619, PAK4 gene) was replicated (P = 0.029) and reached genome-wide significance (P = 2.73 × 10-8) in a combined analysis. These findings were robust to a sensitivity analysis evaluating other potential confounders. We identified and replicated a novel CpG methylation loci (cg14010619) associated with ototoxicity severity. Methylation at cg14010619 may modify PAK4 activity, which has been implicated in cisplatin resistance in malignant cell lines.

The Role of PAK1 in a Gut Manipulation Model of Ileus

Feeding intolerance is prevalent in surgical, critically ill, and trauma patients leading to prolonged hospital and intensive care unit stays, increased infectious and thromboembolic complications, and increased patient care costs. Ileus is a slowing of intestinal motility which contributes to feeding intolerance. At present there are no effective pharmacological treatments for preventing or treating feeding ileus. In previous studies, we have shown that upregulation of PAK1 activity inhibited intestinal contractility in an intestinal edema model of ileus. The purpose of this study was to determine if PAK1 also contributed to decreased intestinal contractility in a gut manipulation model of ileus. We hypothesized that, after gut manipulation, increased inflammatory mediators cause PAK1 activation leading to decreased intestinal contractility. We utilized both mouse and rat models. Ileus was induced by gently rolling the entire length of the small intestine between two cotton tipped applicators three times. Contractile activity was measured ex vivo in an organ bath system. PAK1 levels and Raf phosphorylation were measured by western blotting. In both mouse and rat models, we found that PAK1 expression was increased after gut manipulation. Inhibition of PAK1, as well as PAK1 genetic ablation, attenuated the decreased contractility induced by gut manipulation. PAK1 inhibition also improved response to carbachol in mice after gut manipulation. Pretreatment with a Rho kinase inhibitor blocked the effects of PAK1 inhibitors on contractile activity. CXCL1 and LIX, both CXCR2 ligands, were significantly upregulated within 1 hour after gut manipulation in intestinal smooth muscle. We found that CXCL1 can increase Raf1 phosphorylation, a known PAK1 target, and decrease MLC phosphorylation in primary human intestinal smooth muscle cells. CXCL1 also reduced the response to carbachol in rats. Taken together, these data suggest that PAK1 mediates the inhibitory effects of several inflammatory cytokines on intestinal contractility after gut manipulation. PAK1 is a potential drug target for the treatment of ileus.

Quercetin Promotes the Expression of Genes Involved in Phagocytosis in Bovine Neutrophils

This study was conducted to explore the effect of Quercetin (QH) on phagocytosis of bovine neutrophils. Neutrophils were isolated from fifteen multiparous Holstein cows. We in vitro treated neutrophils with PBS or 50 µM of Quercetin (QH) or Cytochalasin B (CytB), as phagocytosis inhibitor, prior to monitoring phagocytosis of Escherichia coli by flow cytometry and microscopic examination. Additionally, the expressions of CORO1A, CYBA (gp91phox), LAMP1, RAB7A, RAC1 and PAK1 mRNA were analyzed by real-time PCR. In the time-course experiment, treated neutrophils were allowed to co-cultured with live bacteria for 30, 60 and 90 min before measuring gene expressions. The expression levels of IL-1 β and TNF genes in order to demonstrate the anti-inflammatory property of quercetin were assessed by conventional RT-PCR. The results of flow cytometry and microscopic examination showed that the percentage of neutrophils performing phagocytosis were significantly higher in QH group in comparison with other groups. We reported here that mRNA expressions of CORO1A, CYBA, LAMP1, RAB7A, RAC1 and PAK1 genes involved in phagocytosis, were significantly up-regulated in QH group. As expected, CytB group had profound down-regulation of genes with one exception in PAK1. From our observations, the expression levels of phagocytic process genes in the QH group were optimum at 60 min and started to decline at 90 min of incubation. The data also indicated that quercetin inhibited inflammation by reducing the expressions of both IL-1β and TNF. In conclusion, the information in our experiments conclude that quercetin has the ability to boost the expression of genes involved in phagocytosis while reduces the expression of proinflammatory genes.

A de novo mutation in the X-linked PAK3 gene is the underlying cause of intellectual disability and macrocephaly in monozygotic twins

Pathogenic variants in theP21 protein (Cdc42/Rac)-activated kinase 3gene (PAK3) lead to a rare non syndromic X-linked intellectual disability. The protein encoded by this gene forms an activated complex with GTP-bound RAS-like (P21), CDC2 and RAC1 proteins which then mediates a variety of cellular processes. So far, mutations in PAK3 gene have been reported in few families affected with intellectual disability associated with neurological manifestations such as speech defect, behavioral problem, brain structural abnormalities, microcephaly and cerebral palsy. In this study whole exome sequencing revealed a de novo likely pathogenic variant in PAK3 gene in monozygotic twins presented with intellectual disability, speech delay, behavioral problems and macrocephaly. Macrocephaly was noticed in our patients from birth at 35 weeks of gestation. This aspect of the phenotype has not been previously reported in other documented cases with pathogenic mutations in PAK3 gene. Our findings extend the phenotype of this disorder to include macrocephaly and offers further clues to the importance of the serine/threonine-protein kinase 3 (PAK3) protein in brain development and function.

MLST-Based Population Genetic Analysis in a Global Context Reveals Clonality amongst Cryptococcus neoformans var. grubii VNI Isolates from HIV Patients in Southeastern Brazil.

Cryptococcosis is an important fungal infection in immunocompromised individuals, especially those infected with HIV. In Brazil, despite the free availability of antiretroviral therapy (ART) in the public health system, the mortality rate due to Cryptococcus neoformans meningitis is still high. To obtain a more detailed picture of the population genetic structure of this species in southeast Brazil, we studied 108 clinical isolates from 101 patients and 35 environmental isolates. Among the patients, 59% had a fatal outcome mainly in HIV-positive male patients. All the isolates were found to be C. neoformans var. grubii major molecular type VNI and mating type locus alpha. Twelve were identified as diploid by flow cytometry, being homozygous (AαAα) for the mating type and by PCR screening of the STE20, GPA1, and PAK1 genes. Using the ISHAM consensus multilocus sequence typing (MLST) scheme, 13 sequence types (ST) were identified, with one being newly described. ST93 was identified from 81 (75%) of the clinical isolates, while ST77 and ST93 were identified from 19 (54%) and 10 (29%) environmental isolates, respectively. The southeastern Brazilian isolates had an overwhelming clonal population structure. When compared with populations from different continents based on data extracted from the ISHAM-MLST database (mlst.mycologylab.org) they showed less genetic variability. Two main clusters within C. neoformans var. grubii VNI were identified that diverged from VNB around 0.58 to 4.8 million years ago.

Genetic variation in the 3'-untranslated region of PAK1 influences schizophrenia susceptibility.

The present study aimed to investigate the association of two polymorphisms (rs2844337 and rs11237200) in the P21 protein (cell division control protein 42/Rac)-activated kinase 1 gene with susceptibility to schizophrenia (SCZ) in Chinese Zhuang and Chinese Han populations. A total of 700 patients with SCZ and 700 healthy controls were recruited. Rs2844337 and rs11237200 polymorphisms were genotyped using Sequenom technology. A total of 591 patients completed the Positive and Negative Syndrome Scale (PANSS) assessment. Data were statistically analyzed using PLINK version 1.07 and SPSS version 17.0. In the Chinese Han population, the genotypic (P=0.038) and allelic (P=0.033) frequencies of the 3'-untranslated region (UTR) genetic variation of rs2844337 in patients were significantly decreased compared to that in controls; these frequencies were significantly associated with SCZ susceptibility in the additive model (Padj=0.032) and in the recessive model (Padj=0.031). Moreover, the TG haplotype constructed by rs2844337 and rs11237200 polymorphisms remained significantly associated with SCZ risk following adjustment for gender and age and applying a Bonferroni correction in the Chinese Han population (Padj=0.003, PBC=0.009). The adjacent 5'-UTR genetic variation of rs11237200 was significantly associated with the total score (Padj=0.006), positive scale score (Padj=0.014) and general psychopathology scale scores (Padj=0.009) in the recessive model of the Chinese Han population. However, these polymorphisms were not significantly associated with SCZ susceptibility or the PANSS scores in the Chinese Zhuang population. In conclusion, variations in the PAK1 gene influenced the susceptibility and severity of the clinical symptoms of SCZ in the Chinese Han population investigated in the present study.

The intellectual disability protein PAK3 regulates oligodendrocyte precursor cell differentiation

Oligodendrocyte and myelin deficits have been reported in mental/psychiatric diseases. The p21-activated kinase 3 (PAK3), a serine/threonine kinase, whose activity is stimulated by the binding of active Rac and Cdc42 GTPases is affected in these pathologies. Indeed, many mutations of Pak3 gene have been described in non-syndromic intellectual disability diseases. Pak3 is expressed mainly in the brain where its role has been investigated in neurons but not in glial cells. Here, we showed that PAK3 is highly expressed in oligodendrocyte precursors (OPCs) and its expression decreases in mature oligodendrocytes. In the developing white matter of the Pak3 knockout mice, we found defects of oligodendrocyte differentiation in the corpus callosum and to a lesser extent in the anterior commissure, which were compensated at the adult stage. In vitro experiments in OPC cultures, derived from Pak3 knockout and wild type brains, support a developmental and cell-autonomous role for PAK3 in regulating OPC differentiation into mature oligodendrocytes. Moreover, we did not detect any obvious alterations of the proliferation or migration of Pak3 null OPCs compared to wild type. Overall, our data highlight PAK3 as a new regulator of OPC differentiation.

Abstract LB-011: PAK1 inhibitor FRAX1036 sensitizes ovarian cancer cells with amplified 11q13 to cytotoxic effect of rottlerin

Abstract p21-activated kinases (PAKs) are Cdc42/Rac-activated serine-threonine protein kinases that regulate several key cancer-relevant signaling pathways, such as the Mek/Erk, PI3K/Akt, and Wnt/b-catenin. Pak1 is frequently overexpressed and/or hyperactivated in different human cancers, including human breast, ovary, prostate, and brain cancer, due to amplification of the PAK1 gene in an 11q13 amplicon. In our previous in vitro and in vivo studies we have shown that ovarian cancer cells with amplified/overexpressed Pak1 were significantly more sensitive to pharmacologic or genetic inhibition of Pak1 compared to cells without 11q13 amplification. In the present study we examined the combination effect of the Pak1 inhibitor FRAX1036 in ovarian cancer cells using ICCB Known Bioactives Library (Enzo). We found that the cytotoxic effect of FRAX1036 was significantly higher when combined with the PKC delta inhibitor, Rottlerin. We tested FRAX1036 alone and in combination with Rottlerin on 11q13-amplified human ovarian cancer cell lines with respect to cell proliferation, migration and apoptosis. FRAX1036 alone inhibited cell proliferation and migration in 11q13-amplified ovarian cancer cell lines. Co-administration of FRAX1036 with Rottlerin further synergized the inhibition of cell proliferation in vitro and decreased tumor growth in vivo. To explain the synergistic inhibition of cell proliferation induced by the FRAX1036/Rottlerin combination we analyzed Pak1 and PKC delta down-stream signaling molecules. Western blot data indicated that FRAX1036 and Rottlerin synergistically inhibited phosphorylation of critical signaling molecules such as MEK, ERK1/2, b-Catenin, and 4EBP1. Our findings suggest that Pak1 small molecule inhibitors in combination with Rottlerin hold potential clinical value as chemotherapeutic drugs for the ∼25% of ovarian cancers characterized by PAK1 gene amplification. Citation Format: Tatiana Prudnikova, Jonathan Chernoff. PAK1 inhibitor FRAX1036 sensitizes ovarian cancer cells with amplified 11q13 to cytotoxic effect of rottlerin. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-011.

The serum/PDGF-dependent "melanogenic" role of the minute level of the oncogenic kinase PAK1 in melanoma cells proven by the highly sensitive kinase assay.

We previously demonstrated that the oncogenic kinase PAK4, which both melanomas and normal melanocytes express at a very high level, is essential for their melanogenesis. In the present study, using the highly sensitive "Macaroni-Western" (IP-ATP-Glo) kinase assay, we investigated the melanogenic potential of another oncogenic kinase PAK1, which melanoma (B16F10) cells express only at a very minute level. After transfecting melanoma cells with PAK1-shRNA for silencing PAK1 gene, melanin content, tyrosinase activity, and kinase activity of PAK1 were compared between the wild-type and transfectants. We found that (i) PAK1 is significantly activated by melanogenic hormones such as IBMX (3-isobutyl-1-methyl xanthine) and α-MSH (melanocyte-stimulating hormone), (ii) silencing the endogenous PAK1 gene in melanoma cells through PAK1-specific shRNA reduces both melanin content and tyrosinase activity in the presence of both serum and melanogenic hormones to the basal level, (iii) the exogenously added wild-type PAK1 in the melanoma cells boosts the α-MSH-inducible melanin level by several folds without affecting the basal, and (iv) α-MSH/IBMX-induced melanogenesis hardly takes place in the absence of either serum or PAK1, clearly indicating that PAK1 is essential mainly for serum- and α-MSH/IBMX-dependent melanogenesis, but not the basal, in melanoma cells. The outcome of this study might provide the first scientific basis for explaining why a wide variety of herbal PAK1-blockers such as CAPE (caffeic acid phenethyl ester), curcumin and shikonin in cosmetics are useful for skin-whitening.

P21-activated kinase group II small compound inhibitor GNE-2861 perturbs estrogen receptor alpha signaling and restores tamoxifen-sensitivity in breast cancer cells.

Estrogen receptor alpha (ERα) is highly expressed in most breast cancers. Consequently, ERα modulators, such as tamoxifen, are successful in breast cancer treatment, although tamoxifen resistance is commonly observed. While tamoxifen resistance may be caused by altered ERα signaling, the molecular mechanisms regulating ERα signaling and tamoxifen resistance are not entirely clear. Here, we found that PAK4 expression was consistently correlated to poor patient outcome in endocrine treated and tamoxifen-only treated breast cancer patients. Importantly, while PAK4 overexpression promoted tamoxifen resistance in MCF-7 human breast cancer cells, pharmacological treatment with a group II PAK (PAK4, 5, 6) inhibitor, GNE-2861, sensitized tamoxifen resistant MCF-7/LCC2 breast cancer cells to tamoxifen. Mechanistically, we identified a regulatory positive feedback loop, where ERα bound to the PAK4 gene, thereby promoting PAK4 expression, while PAK4 in turn stabilized the ERα protein, activated ERα transcriptional activity and ERα target gene expression. Further, PAK4 phosphorylated ERα-Ser305, a phosphorylation event needed for the PAK4 activation of ERα-dependent transcription. In conclusion, PAK4 may be a suitable target for perturbing ERα signaling and tamoxifen resistance in breast cancer patients.

The potential role of the NEK6, AURKA, AURKB, and PAK1 genes in adenomatous colorectal polyps and colorectal adenocarcinoma.

Colorectal adenomatous polyp (CRAP) is a major risk factor for the development of sporadic colorectal cancer (CRC). Histone modifications are one of the epigenetic mechanisms that may have key roles in the carcinogenesis of CRC. The objective of the present study is to investigate the alternations in the defined histone modification gene expression profiles in patients with CRAP and CRC. Histone modification enzyme key gene expressions of the CRC, CRAP, and control groups were evaluated and compared using the reverse transcription PCR (RT-PCR) array method. Gene expression analysis was performed in the CRAP group after dividing the patients into subgroups according to the polyp diameter, pathological results, and morphological parameters which are risk factors for developing CRC in patients with CRAP. PAK1, NEK6, AURKA, AURKB, HDAC1, and HDAC7 were significantly more overexpressed in CRC subjects compared to the controls (p < 0.05). PAK1, NEK6, AURKA, AURKB, and HDAC1 were significantly more overexpressed in the CRAP group compared to the controls (p < 0.005). There were no significant differences between the CRAP and CRC groups with regards to PAK1, NEK6, AURKA, or AURKB gene overexpression. PAK1, NEK6, AURKA, and AURKB were significantly in correlation with the polyp diameter as they were more overexpressed in polyps with larger diameters. In conclusion, overexpressions of NEK6, AURKA, AURKB, and PAK1 genes can be used as predictive markers to decide the colonoscopic surveillance intervals after the polypectomy procedure especially in polyps with larger diameters.

Never in mitosis gene A-related kinase 6 and aurora kinase A: New gene biomarkers in the conversion from ulcerative colitis to colorectal cancer.

Ulcerative colitis (UC) is an important risk factor for colorectal cancer (CRC). Histone modifications are one of the epigenetic mechanisms that may have key roles in the carcinogenesis of CRC. At present, there are no studies comparing histone modification patterns of UC and CRC in the literature. Therefore the aim of the present study was to investigate whether genes, particularly those involved in histone modification, have value in patient monitoring with regards to CRC development in UC. Key gene expressions of the histone modification enzyme were assessed and compared in CRC, UC and control groups using the RT-PCR array technique. Patients were divided into subgroups based on the extent and duration of the disease and inflammatory burden, which are considered risk factors for CRC development in UC patients. In UC and CRC groups, a significantly higher overexpression of the NEK6 and AURKA genes compared to the control group was identified. In addition, there was a significantly higher overexpression of HDAC1 and PAK1 genes in the UC group, and of HDAC1, HDAC7, PAK1 and AURKB genes in the CRC group. NEK6, AURKA, HDAC1 and PAK1 were significantly overexpressed in patients with a longer UC duration. Overexpression of AURKA and NEK6 genes was significantly more pronounced in UC patients with more extensive colon involvement. HDAC1, HDAC7, PAK1, NEK6, AURKA and AURKB are important diagnostic and prognostic markers involved in the carcinogenesis of CRC. HDAC1, PAK1, NEK6 and AURKA may be considered as diagnostic markers to be used in CRC screening for UC patients.

Effects of p21-activated kinase 1 inhibition on 11q13-amplified ovarian cancer cells.

p21-activated kinases (PAKs) are Cdc42/Rac–activated serine-threonine protein kinases that regulate of several key cancer-relevant signaling pathways, such as the Mek/Erk, PI3K/Akt, and Wnt/b-catenin signaling pathways. Pak1 is frequently overexpressed and/or hyperactivated in different human cancers, including human breast, ovary, prostate, and brain cancer, due to amplification of the PAK1 gene in an 11q13 amplicon. Genetic or pharmacological inactivation of Pak1 has been shown to reduce proliferation of different cancer cells in vitro and reduce tumor progression in vivo.In this work, we examined the roles of Pak1 in cellular and animal models of PAK1-amplified ovarian cancer. We found that inhibition of Pak1 leads to decreased proliferation and migration in PAK1 amplified/overexpressed ovarian cancer cells, and has no effect in cell that lack such amplification/overexpression. Further, we observed that loss of Pak1 function causes 11q13 amplified ovarian cancer cells to arrest in the G2/M phase of the cell cycle. This arrest correlates with activation of p53 and p21Cip and decreased expression of cyclin B1. These findings suggest that small molecule inhibitors of Pak1 may play a therapeutic role in the ~25% of ovarian cancers characterized by PAK1 gene amplification.

MiR-30c Mediates Upregulation of Cdc42 and Pak1 in Diabetic Cardiomyopathy.

Cardiac hypertrophy and myocardial fibrosis significantly contribute to the pathogenesis of diabetic cardiomyopathy (DCM). Altered expression of several genes and their regulation by microRNAs has been reported in hypertrophied failing hearts. This study aims to examine the role of Cdc42, Pak1, and miR-30c in the pathogenesis of cardiac hypertrophy in DCM. DCM was induced in Wistar rats by low-dose streptozotocin-high-fat diet for 12 weeks. Cardiac expression of Cdc42, Pak1 and miR-30c, and hypertrophy markers (ANP and β-MHC) was studied in DCM vs control rats and in high-glucose (HG)-treated H9c2 cardiomyocytes. Diabetic rats showed cardiomyocyte hypertrophy, increased heart-to-body weight ratio, and an increased expression of ANP and β-MHC. Cardiac expression of Cdc42 and Pak1 genes was increased in diabetic hearts and in HG-treated cardiomyocytes. miR-30c was identified to target Cdc42 and Pak1 genes, and cardiac miR-30c expression was found to be decreased in DCM rats, patients with DCM, and in HG-treated cardiomyocytes. miR-30c overexpression decreased Cdc42 and Pak1 genes and attenuated HG-induced cardiomyocyte hypertrophy, whereas miR-30c inhibition increased Cdc42 and Pak1 gene expression and myocyte hypertrophy in HG-treated cardiomyocytes. Downregulation of miR-30c mediates prohypertrophic effects of hyperglycemia in DCM by upregulation of Cdc42 and Pak1 genes.

P21-activated kinase 1 and 4 were associated with colorectal cancer metastasis and infiltration

BackgroundP21-activated kinases (PAKs) are small guanosine triphosphate effectors that play critical roles in many fundamental cellular functions, including cytoskeletal reorganization and cell motility. PAKs are widely expressed in a variety of tissues and are often overexpressed in multiple cancer types. The aim of this study was to investigate the relationship between PAK1 and PAK4 and clinicopathologic features of colorectal cancer. MethodsPAK1 and PAK4 expression in colorectal cancer patients were investigated via TaqMan real-time polymerase chain reaction and immunohistochemistry and clinical analysis. ResultsThe relative expression levels of PAK1 and PAK4 gene in colorectal carcinoma tissues were significantly higher than those in normal tissues (P < 0.01). PAK4 expression was higher than PAK1 in the same cancer tissue. The expression of PAK1 and PAK4 increased gradually with the clinical stages in carcinoma tissues (P < 0.01). PAK1 expression was higher in lymph node positive patients, and PAK4 expression was higher in infiltration into serous layer patients (P < 0.05). PAK1 overexpression group has a higher recurrence/metastasis rate compared with that of the PAK1 low expression group. Follow-up analysis showed that the median progression-free survival time of the PAK1 high expression group was significantly shorter than that of the PAK1 low expression group. ConclusionsPAK1 and PAK4 expression were associated with colorectal cancer metastasis and infiltration, PAK1 high expression may indicate poor prognosis of colorectal cancer.