Knockdown of PAK1 Inhibits the Proliferation and Invasion of Non-Small Cell Lung Cancer Cells Through the ERK Pathway

Activation of oncogenic signaling kinase PAK1 by ionising radiation confers an aggressive phenotype in head and neck squamous cell carcinoma

Head and neck squamous cancers are very aggressive tumors often diagnosed in late stages with poor prognosis. HNSCCs are usually treated by a course of radiation (IR) therapy and followed by surgery. These treatment regimens fail to bring a complete response. Molecular signatures in tumors are attributed to this response and an improved understanding of the signaling events could offer new avenues for therapy. Here, we show that P21 activated kinase-1 (PAK1) - an oncogenic signaling serine/threonine kinase, is activated upon exposure to IR and this leads to an accelerated tumorigenic character in HNSCC cells. Our results show that PAK1 is highly expressed in HNSCC cell lines, as compared to normal buccal mucosa cells and when HNSCC cells were exposed to IR, they show activated PAK1 and an aggressive phenotype as determined by in vitro functional assays. PAK1 levels were elevated in HNSCC as compared to adjacent normal oral tissues and our results also show convincing evidence of activated PAK1 in patient tumor samples of post- IR treatment as compared to pre-IR treatment and is associated with poor survival. Pak1 Knockout (KO) clones in HNSCC cells showed that they were more sensitive to IR as compared to wild type (wt) cells. This altered sensitivity to IR was attributed to enhanced DNA damage response modulated by PAK1 in cells. Overall, our results suggest that PAK1 expression in HNSCC could be a critical determinant in IR therapy response and silencing PAK1 is likely to be a treatment modality to improve clinical outcomes.

PAK in Pancreatic Cancer-Associated Vasculature: Implications for Therapeutic Response

Angiogenesis has been associated with numbers of solid tumours. Anti-angiogenesis drugs starve tumours of nutrients and oxygen but also make it difficult for a chemo reagent to distribute into a tumour, leading to aggressive tumour growth. Anti-angiogenesis drugs do not appear to improve the overall survival rate of pancreatic cancer. Vessel normalisation is merging as one of the new approaches for halting tumour progression by facilitating the tumour infiltration of immune cells and the delivery of chemo reagents. Targeting p21-activated kinases (PAKs) in cancer has been shown to inhibit cancer cell growth and improve the efficacy of chemotherapy. Inhibition of PAK enhances anti-tumour immunity and stimulates the efficacy of immune checkpoint blockades. Inhibition of PAK also improves Car-T immunotherapy by reprogramming the vascular microenvironment. This review summarizes current research on PAK's role in tumour vasculature and therapeutical response, with a focus on pancreatic cancer.

Clinicopathological significance and the associated signaling pathway of p21-activated kinase 1 (PAK1) in colorectal cancer

The aim of this study was to evaluate the clinicopathological significance and associated signaling pathways of p21-activated kinase 1 (PAK1) in colorectal cancer (CRC). PAK1 immunohistochemical expression was investigated in 246 human CRC tissues to evaluate its clinicopathological significance and prognostic role. Correlations between PAK1 and the immunoscore, HIF-1α, and pFOXO1 were also evaluated. PAK1 was expressed in 169 of 246 CRC tissues (68.7%). PAK1 expression significantly correlated with the metastatic lymph node ratio (P = 0.023). However, PAK1 expression did not correlate with tumor size, tumor location, tumor differentiation, lymphovascular and perineural invasion, or distant metastasis. PAK1 expression was significantly higher in CRC with a low immunoscore than in CRC with a high immunoscore (P = 0.017). In addition, there were significant correlations between PAK1, HIF-1α, and pFOXO1 expression (P = 0.001 and P = 0.024, respectively). Patients with PAK1 expression had worse overall and recurrence-free survival than those without PAK1 expression (P 0.001 and P = 0.001, respectively). PAK1 expression was significantly correlated with worse prognosis in CRCs patients. In addition, PAK1 expression was significantly correlated with a low immunoscore and high expression of HIF-1α and pFOXO1 in CRCs.

Immune- and Stemness-Related Genes Revealed by Comprehensive Analysis and Validation for Cancer Immunity and Prognosis and Its Nomogram in Lung Adenocarcinoma

Objective

Lung adenocarcinoma (LUAD) is a familiar lung cancer with a very poor prognosis. This study investigated the immune- and stemness-related genes to develop model related with cancer immunity and prognosis in LUAD.

Method

The Cancer Genome Atlas (TCGA) was utilized for obtaining original transcriptome data and clinical information. Differential expression, prognostic value, and correlation with clinic parameter of mRNA stemness index (mRNAsi) were conducted in LUAD. Significant mRNAsi-related module and hub genes were screened using weighted gene coexpression network analysis (WGCNA). Meanwhile, immune-related differential genes (IRGs) were screened in LUAD. Stem cell index and immune-related differential genes (SC-IRGs) were screened and further developed to construct prognosis-related model and nomogram. Comprehensive analysis of hub genes and subgroups, involving enrichment in the subgroup [gene set enrichment analysis (GSEA)], gene mutation, genetic correlation, gene expression, immune, tumor mutation burden (TMB), and drug sensitivity, used bioinformatics and reverse transcription polymerase chain reaction (RT-PCR) for verification.

Results

Through difference analysis, mRNAsi of LUAD group was markedly higher than that of normal group. Clinical parameters (age, gender, and T staging) were ascertained to be highly relevant to mRNAsi. MEturquoise and MEblue were found to be the most significant modules (including positive and negative correlations) related to mRNAsi via WGCNA. The functions and pathways of the two mRNAsi-related modules were mainly enriched in tumorigenesis, development, and metastasis. Combining stem cell index-related differential genes and immune-related differential genes, 30 prognosis-related SC-IRGs were screened via Cox regression analysis. Then, 16 prognosis-related SC-IRGs were screened to construct a LASSO regression model at last. In addition, the model was successfully validated by using TCGA-LUAD and GSE68465, whereas c-index and the calibration curves were utilized to demonstrate the clinical value of our nomogram. Following the validation of the model, GSEA, immune cell correlation, TMB, clinical relevance, etc., have found significant difference in high- and low-risk groups, and 16-gene expression of the SC-IRG model also was tested by RT-PCR. ADRB2, ANGPTL4, BDNF, CBLC, CX3CR1, and IL3RA were found markedly different expression between the tumor and normal group.

Conclusion

The SC-IRG model and the prognostic nomogram could accurately predict LUAD survival. Our study used mRNAsi combined with immunity that may lay a foundation for the future research studies in LUAD.

Circular RNA hsa_circ_0004396 acts as a sponge of miR-615-5p to promote non-small cell lung cancer progression and radioresistance through the upregulation of P21-Activated Kinase 1

BACKGROUNDS

CircRNA hsa_circ_0004396 has been confirmed to be upregulated in human non-small cell lung cancer (NSCLC). The aim of his study was to evaluate its mechanism in the radioresistance and progression of NSCLC.

METHODS

Hsa_circ_0004396, miR-615-5p, and P21-Activated Kinase 1 (PAK1) were measured by reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR). The binding between miR-615-5p and hsa_circ_0004396 or PAK1 was predicted by circinteractome or Targetscan, as verified by dual-luciferase reporter assay and RIP assay. Proliferation, clonogenicity capacity, cell cycle progression, apoptosis, migration, and invasion were assessed by CCK-8, colony formation, flow cytometry, and Transwell assay. Bcl-2, Bcl-2 associated protein X (Bax), MMP-2, and PAK1 protein levels were detected using western blot assay. In addition, in vivo function of hsa_circ_0004396 was evaluated by tumor xenograft assay.

RESULTS

Hsa_circ_0004396 and PAK1 levels were upregulated, while miR-615-5p was declined in NSCLC. Hsa_circ_0004396 silencing inhibited NSCLC cell malignant behavior and induced radiosensitivity. Hsa_circ_0004396 functions as a molecular sponge of miR-615-5p to regulate PAK1 expression. Moreover, hsa_circ_0004396 knockdown inhibited NSCLC tumor growth in vivo.

CONCLUSION

Our findings demonstrated that hsa_circ_0004396 promoted NSCLC development and radioresistance through the miR-615-5p/PAK1 axis, which might provide a new therapeutic target for NSCLC treatment.

Cytoplasmic P120ctn Promotes Gefitinib Resistance in Lung Cancer Cells by Activating PAK1 and ERK Pathway

Our previous studies indicated that cytoplasmic p120ctn mediated epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKI) resistance in lung cancer. In the present study, we aim to further explore the underlying molecular mechanisms. Immunohistochemistry detected PAK1, Cdc42, and Rac1 expression in lung cancer with cytoplasmic p120ctn. Immunoblotting, protein activity analysis, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide evaluated p120ctn location, PAK1, Cdc42/Rac1, and extracellular signal-regulated kinase (ERK) activity in response to TKI treatment in HCC827 and PC9 cell lines, as well as the cell sensitivity to Gefitinib. Most non-small cell lung cancer patients with cytoplasmic p120ctn showed enhanced PAK1 and Cdc42/Rac1. When Gefitinib resistance was induced, cytoplasmic p120ctn is accompanied with increasing PAK1 and Cdc42/Rac1. Cytoplasmic p120ctn activated ERK via PAK1, while PAK1 downregulation attenuated ERK activation by cytoplasmic p120ctn. After Cdc42/Rac1 inhibition, cytoplasmic p120ctn could not activate PAK1. Cytoplasmic p120ctn activates PAK1 via Cdc42/Rac1 activation, constitutively activates ERK in the EGFR downstream signaling, and promotes EGFR-TKI resistance in lung cancer cells. The current study will aid to screen the subpopulation patients who would benefit from therapy with first-generation EGFR-TKIs.

Effect of differential hypoxia-related gene expression on glioblastoma

Objective

Glioblastoma (GB) is a refractory malignancy with a high rate of recurrence and treatment resistance. Hypoxia-related genes are promising prognostic indicators for GB, so we herein developed a reliable hypoxia-related gene risk scoring model to predict the prognosis of patients with GB.

Method

Gene expression profiles and corresponding clinicopathological features of patients with GB were obtained from the Cancer Genome Atlas (TCGA; n = 160) and Gene Expression Omnibus (GEO) GSE7696 (n = 80) databases. Univariate and multivariate Cox regression analyses of differentially expressed hypoxia-related genes were performed using R 3.5.1 software.

Result

Fourteen prognosis-related genes were identified and used to construct a risk signature. Patients with high-risk scores had significantly lower overall survival (OS) than those with low-risk scores. The median risk score was used as a critical value and for OS prediction in an independent external verification GSE7696 cohort. Risk score was not significantly affected by clinical-related factors. We also developed a prediction nomogram based on the TCGA training set to predict survival rates, and included six independent prognostic parameters in the TCGA prediction model.

Conclusion

We determined a reliable hypoxia-related gene risk scoring model for predicting the prognosis of patients with GB.

Use of cucurbitacins for lung cancer research and therapy

As the main substance in some traditional Chinese medicines, cucurbitacins have been used to treat hepatitis for decades in China. Currently, the use of cucurbitacins against cancer and other diseases has achieved towering popularity among researchers worldwide, as detailed in this review with summarized tables. Numerous studies have reported the potential tumor-killing activities of cucurbitacins in multiple aspects of human malignancies. Continuous research on its anticancer activity mechanisms also brings a glimmer of light to the treatment of patients with lung cancer. In line with the promising roles of cucurbitacins against cancer, through various molecular signaling pathways, it is justifiable to propose the use of cucurbitacins as a potential mainline chemotherapy before the onset and after the diagnosis of lung cancers. Here, this article mainly summarized the findings about the biological functions and underlying mechanisms of cucurbitacins on lung cancer pathogenesis and treatment. In addition, we also discussed the safety and efficacy of their application for further research and even clinical practice.

Overexpression of RhoV Promotes the Progression and EGFR-TKI Resistance of Lung Adenocarcinoma

Background

The Rho GTPase family with ~20 member genes play central roles in a wide variety of cellular processes and tumor cell migration and metastasis. Different Rho GTPase may play different roles in the progression of lung adenocarcinoma.

Methods

We comprehensively examined the expression of all Rho GTPase family member genes in a panel of lung adenocarcinoma patient’s tumors and matched normal tissues. We next investigated the critical role of RhoV in different lung adenocarcinoma cells and animal models.

Results

RhoV was identified as one of the most significantly overexpressed Rho GTPases in lung adenocarcinoma and associated with patients’ survival. Silencing RhoV expression inhibits proliferation, migration and invasion, and tumorigenicity capacities of lung adenocarcinoma cells. Moreover, knockdown RhoV promoted the sensitivity of EGFR-TKI in the gefitinib resistant PC9 cells (PC9-GR) and aggravated gefitinib-induced lung cancer cell apoptosis both in PC9 and PC9-GR cells. Our data also indicated that RhoV induced progression and EGFR-TKI resistance of lung adenocarcinoma may be related to the activation of the AKT/ERK pathway.

Conclusion

Overexpression of RhoV in lung adenocarcinoma promotes the progression and EGFR-TKI resistance, suggesting RhoV is a promising prognosis and therapeutic target of lung adenocarcinoma.

PAK1 as a Potential Therapeutic Target in Male Smokers with EGFR-Mutant Non-Small Cell Lung Cancer

P21-activated kinases (PAKs) are serine/threonine protein kinases that contribute to several cellular processes. Here, we aimed to determine the prognostic value of PAK1 and its correlation with the clinicopathological characteristics and five-year survival rates in patients with non-small cell lung cancer (NSCLC). We evaluated PAK1 mRNA and protein expression in NSCLC cells and resected tumor specimens, as well as in healthy human bronchial epithelial cells and adjacent healthy lung tissues, respectively, for effective comparison. Immunohistochemical tissue microarray analysis of 201 NSCLC specimens showed the correlation of PAK1 expression with clinicopathological characteristics. The mRNA and protein expression of PAK1 were 2.9- and 4.3-fold higher in six of seven NSCLC cell types and human tumors (both, p < 0.001) than in healthy human bronchial epithelial BEAS-2B cells and adjacent healthy lung tissues, respectively. Decreased survival was significantly associated with PAK1 overexpression in the entire cohort (χ² = 8.48, p = 0.0036), men (χ² = 17.1, p < 0.0001), and current and former smokers (χ² = 19.2, p < 0.0001). Notably, epidermal growth factor receptor (EGFR) mutation-positive lung cancer patients with high PAK1 expression showed higher mortality rates than those with low PAK1 expression (91.3% vs. 62.5%, p = 0.02). Therefore, PAK1 overexpression could serve as a molecular target for the treatment of EGFR mutation-positive lung cancer, especially among male patients and current/former smokers.

Desmoglein-2 modulates tumor progression and osimertinib drug resistance through the EGFR/Src/PAK1 pathway in lung adenocarcinoma

Desmoglein-2 (DSG2), a member of the cadherin superfamily, has been implicated in cell-cell adhesion and tumorigenesis. Here, we demonstrate that high DSG2 expression in both lung adenocarcinoma (LUAD) cell lines and tissues is associated with poor prognosis in LUAD patients. Notably, DSG2 overexpression promoted cell proliferation and migration, and increased resistance to the EGFR tyrosine kinase inhibitor osimertinib, whereas DSG2 silencing could reverse these results. Moreover, direct interaction between DSG2 and EGFR in the cell membrane stimulated EGFR signaling to promote tumorigenesis, and loss of DSG2 resulted in EGFR translocation into the cytoplasm. In addition, DSG2 was required for EGFR binding to Src; consequently, DSG2 silencing inhibited tumor cell malignancy via suppression of the EGFR-Src-Rac1-PAK1 signaling pathway. Consistent with these findings, a nude mouse xenograft model using H1975 cells demonstrated that DSG2 promoted LUAD cell growth in vivo and increased osimertinib resistance. Collectively, these observations are the first to elucidate a unique role for DSG2 in the development and progression of lung adenocarcinoma via EGFR signaling.

miR-107 inhibited malignant biological behavior of non-small cell lung cancer cells by regulating the STK33/ERK signaling pathway in vivo and vitro

Background

The role of miRNAs in non-small cell lung cancer (NSCLC) has been broadly studied and confirmed, and miR-107 has attracted an ever-growing level of attention. This study set out to research the mechanism of the effect of miR-107 on the malignant biological behavior of NSCLC in vivo and vitro.

Methods

The expression of miRNAs related to the development of NSCLC was detected by RT-qPCR. Western blotting was carried out to detect expression levels of serine/threonine kinase 33 (STK33) and proteins related to the extracellular regulated protein kinases (ERK) signaling pathway, while cell proliferation was detected using cell counting kit-8 (CCK-8). The cell apoptosis rate was measured using flow cytometry. The invasion ability was detected by Transwell assay. In vivo tumor growth assays were performed on mice. The expression ERK signaling pathway-related proteins in vivo was evaluated by immunohistochemistry staining. The targeted relationship between miR-107 and STK33 was confirmed by the dual luciferase reporter gene.

Results

In NSCLC cell lines and tissues, miR-107 was downregulated. Overexpression of miR-107 inhibited malignant biological behavior of NSCLC cell lines, and suppressed tumor growth in vivo. In addition, STK33 is one of the target genes of miR-107. Therefore, miR-107 suppressed cell proliferation and invasion and promoted tumor growth in vivo and cell apoptosis of NSCLC in vitro. The mechanism was found to be miR-107 targeting STK33, and a lack of STK33 led to the activation of ERK signaling pathway.

Conclusions

miR-107 inhibited malignant biological behavior of NSCLC through regulation of the STK33/ERK signaling pathway.