Cervical Cancer Growth Is Regulated by a c-ABL-PLK1 Signaling Axis

Balancing Plk1 activity levels: The secret of synchrony between the cell and the centrosome cycle

The accuracy of cell division requires precise regulation of the cellular machinery governing DNA/genome duplication, ensuring its equal distribution among the daughter cells. The control of the centrosome cycle is crucial for the formation of a bipolar spindle, ensuring error-free segregation of the genome. The cell and centrosome cycles operate in close synchrony along similar principles. Both require a single duplication round in every cell cycle, and both are controlled by the activity of key protein kinases. Nevertheless, our comprehension of the precise cellular mechanisms and critical regulators synchronizing these two cycles remains poorly defined. Here, we present our hypothesis that the spatiotemporal regulation of a dynamic equilibrium of mitotic kinases activities forms a molecular clock that governs the synchronous progression of both the cell and the centrosome cycles.

ABL1-mediated phosphorylation promotes FOXM1-related tumorigenicity by Increasing FOXM1 stability

The transcription factor FOXM1, which plays critical roles in cell cycle progression and tumorigenesis, is highly expressed in rapidly proliferating cells and various tumor tissues, and high FOXM1 expression is related to a poor prognosis. However, the mechanism responsible for FOXM1 dysregulation is not fully understood. Here, we show that ABL1, a nonreceptor tyrosine kinase, contributes to the high expression of FOXM1 and FOXM1-dependent tumor development. Mechanistically, ABL1 directly binds FOXM1 and mediates FOXM1 phosphorylation at multiple tyrosine (Y) residues. Among these phospho-Y sites, pY575 is indispensable for FOXM1 stability as phosphorylation at this site protects FOXM1 from ubiquitin-proteasomal degradation. The interaction of FOXM1 with CDH1, a coactivator of the E3 ubiquitin ligase anaphase-promoting complex/cyclosome (APC/C), which is responsible for FOXM1 degradation, is significantly inhibited by Y575 phosphorylation. The phospho-deficient FOXM1(Y575F) mutant exhibited increased ubiquitination, a shortened half-life, and consequently a substantially decreased abundance. Compared to wild-type cells, a homozygous Cr-Y575F cell line expressing endogenous FOXM1(Y575F) that was generated by CRISPR/Cas9 showed obviously delayed mitosis progression, impeded colony formation and inhibited xenotransplanted tumor growth. Overall, our study demonstrates that ABL1 kinase is involved in high FOXM1 expression, providing clear evidence that ABL1 may act as a therapeutic target for the treatment of tumors with high FOXM1 expression.

Polo-Like Kinase 1 and DNA Damage Response

Polo-like kinase 1 (Plk1), an evolutionarily conserved serine/threonine protein kinase, is a key regulator involved in the mitotic process of the cell cycle. Mounting evidence suggests that Plk1 is also involved in a variety of nonmitotic events, including the DNA damage response, DNA replication, cytokinesis, embryonic development, apoptosis, and immune regulation. The DNA damage response (DDR) includes activation of the DNA checkpoint, DNA damage recovery, DNA repair, and apoptosis. Plk1 is not only an important target of the G2/M DNA damage checkpoint but also negatively regulates the G2/M checkpoint commander Ataxia telangiectasia-mutated (ATM), promotes G2/M phase checkpoint recovery, and regulates homologous recombination repair by interacting with Rad51 and BRCA1, the key factors of homologous recombination repair. This article briefly reviews the function of Plk1 in response to DNA damage.

Application of PLK1 and HOXA13 Gene Expression Levels in Urine in the Diagnosis of Non-muscle Invasive Bladder Cancer

Bladder cancer is the most common urinary tract neoplasm, affecting many people annually. Current diagnostic and surveillance methods for bladder cancer are frequently invasive and lack sensitivity and specificity. This study aimed to develop an accurate and non-invasive urine-based gene expression assay, including fibroblast growth factor receptor 3 (FGFR3), homeobox A13 (HOXA13), and polo-like kinase 1 (PLK1), to diagnose non-muscle-invasive bladder cancer (NMIBC) at stages Ta and T1. The samples were acquired from 62 patients with NMIBC, 31 control individuals, and 31 patients with non-cancerous genitourinary tract diseases. The expression levels of three relevant genes were determined using quantitative RT-PCR. In addition, the sensitivity and specificity of the data for these genes were computed. Our results showed that PLK1, HOXA13, and FGFR3 expressions of genes were significantly elevated in patients compared to the control groups (p = 0.0001; p = 0.039). The sensitivity and specificity for the FGFR3 gene were 55% and 76%, respectively (p = 0.39). These parameters for HOXA13 were 100% and 93% (p = 0.0001) and for PLK1 were 100% and 86% (p = 0.0001) for diagnosing and monitoring NMIBC. HOXA13 and PLK 1 exhibited adequate specificity and sensitivity for diagnosis. The results of this research showed that despite the higher expression of these genes in urine, only HOXA13 and PLK1 had sufficient and proper specificity and sensitivity, so the urinary expression of these two genes can be used in future studies for diagnosis and monitoring in cancer bladder.

The Eyes Absent family members EYA4 and EYA1 promote PLK1 activation and successful mitosis through tyrosine dephosphorylation

The Eyes Absent proteins (EYA1-4) are a biochemically unique group of tyrosine phosphatases known to be tumour-promoting across a range of cancer types. To date, the targets of EYA phosphatase activity remain largely uncharacterised. Here, we identify Polo-like kinase 1 (PLK1) as an interactor and phosphatase substrate of EYA4 and EYA1, with pY445 on PLK1 being the primary target site. Dephosphorylation of pY445 in the G2 phase of the cell cycle is required for centrosome maturation, PLK1 localization to centrosomes, and polo-box domain (PBD) dependent interactions between PLK1 and PLK1-activation complexes. Molecular dynamics simulations support the rationale that pY445 confers a structural impairment to PBD-substrate interactions that is relieved by EYA-mediated dephosphorylation. Depletion of EYA4 or EYA1, or chemical inhibition of EYA phosphatase activity, dramatically reduces PLK1 activation, causing mitotic defects and cell death. Overall, we have characterized a phosphotyrosine signalling network governing PLK1 and mitosis.

Eph signal inhibition potentiates the growth-inhibitory effects of PLK1 inhibition toward cancer cells

Anti-mitotic drugs are clinically used as anti-cancer treatments. Polo-like kinase 1 (PLK1) is a promising target against cancer cell division due to its importance in the whole process of mitosis, and thus PLK1-targeting agents have been developed in the last few decades. Clinical trial studies show that several PLK1 inhibitors are generally well-tolerated. However, the response rates are limited; therefore, it is needed to improve the efficacy of those drugs. Here, we show that NVP-BHG712, an erythropoietin-producing human hepatocellular (Eph) signaling inhibitor, potentiates the growth-inhibitory effects of the PLK1 inhibitors BI2536 and BI6727 in cancer cells. This combination treatment strongly suppresses cancer spheroid formation. Moreover, the combination drastically arrests cells at mitosis by continuous activation of the spindle assembly checkpoint (SAC), thereby inducing apoptosis. SAC activation caused by the combination of NVP-BHG712 and BI2536 is due to the inhibition of centrosome maturation and separation. Although the inactivation level of the PLK1 kinase is comparable between BI2536 treatment alone and combination treatment, the combination treatment strongly inactivates MAPK signaling in mitosis. Since inhibition of MAPK signaling potentiates the efficacy of BI2536 treatment, inactivation of PLK1 kinase and MAPK signaling contributes to the strong inhibition of centrosome separation. These results suggest that Eph signal inhibition potentiates the effect of PLK1 inhibition, leading to strong mitotic arrest via SAC activation and the subsequent reduction of cancer cell survival. The combination of PLK1 inhibition and Eph signal inhibition will provide a new effective strategy for targeting cancer cell division.

USP7 promotes non-small-cell lung cancer cell glycolysis and survival by stabilizing and activating c-Abl

BACKGROUND

Abelson tyrosine kinase (c-Abl) is frequently mutated and highly expressed, and promotes non-small-cell lung cancer (NSCLC) survival, metastasis and tumorigenesis. c-Abl could also be modified through ubiquitination, but the underlying mechanism is not well understood.

METHODS

Mass spectrometry assays were performed to search c-Abl deubiquitination enzymes. The molecular mechanism was determined using Co-IP assays, pull-down assays, Western blotting upon gene knockdown or overexpression. Cell lines and animal models were used to investigate the role of c-Abl and USP7 in NSCLC. EdU staining assay and Transwell assay were performed to evaluate the proliferation and migration ability of NSCLC cells, respectively.

RESULTS

Ubiquitin-specific protease 7 (USP7) is found to upregulate c-Abl via the deubiquitinase screen. USP7 interacts with c-Abl and decreases its K48-linked polyubiquitination, thereby increasing the stability of c-Abl. In addition to the wild-type one, c-Abl mutants can also be deubiquitinated and stabilized by USP7. Moreover, USP7 promotes c-Abl accumulation in cytoplasm by increasing its binding to 14-3-3α/β and activates the oncogenic c-Abl signalling pathway. Furthermore, the USP7/c-Abl axis promotes NSCLC cell glycolysis by direct phosphorylating and stabilizing hexokinase-2 (HK2). Knockdown of USP7 or c-Abl suppresses NSCLC cell glycolysis and reduces lactate production. Further studies revealed that overexpression of USP7 facilitates NSCLC cell growth and metastasis as well as xenograft growth in nude mice, while these activities are suppressed with USP7 or c-Abl being knocked down.

CONCLUSIONS

USP7 is a deubiquitinase of c-Abl and upregulates its oncogenic activity. USP7 promotes NSCLC cell metabolism by activating c-Abl and HK2. Targeting the USP7/c-Abl/HK2 axis might be a potential strategy to the precision therapy of NSCLC.

RAIDS atlas of significant genetic and protein biomarkers in cervical cancer

Loss of function in epigenetic acting genes together with driver alterations in the PIK3CA pathway have been shown significantly associated with poor outcome in cervical squamous cell cancer. More recently, a CoxBoost analysis identified 16 gene alterations and 30 high level activated proteins to be of high interest, due to their association with either good or bad outcome, in the context of treatment received by chemoradiation. The objectives here were to review and confirm the significance of these molecular alterations as suggested by literature reports and to pinpoint alternate treatments options for poor-responders to chemoradiation.

Maintaining Genome Integrity: Protein Kinases and Phosphatases Orchestrate the Balancing Act of DNA Double-Strand Breaks Repair in Cancer

DNA double-strand breaks (DSBs) are the most lethal DNA damages which lead to severe genome instability. Phosphorylation is one of the most important protein post-translation modifications involved in DSBs repair regulation. Kinases and phosphatases play coordinating roles in DSB repair by phosphorylating and dephosphorylating various proteins. Recent research has shed light on the importance of maintaining a balance between kinase and phosphatase activities in DSB repair. The interplay between kinases and phosphatases plays an important role in regulating DNA-repair processes, and alterations in their activity can lead to genomic instability and disease. Therefore, study on the function of kinases and phosphatases in DSBs repair is essential for understanding their roles in cancer development and therapeutics. In this review, we summarize the current knowledge of kinases and phosphatases in DSBs repair regulation and highlight the advancements in the development of cancer therapies targeting kinases or phosphatases in DSBs repair pathways. In conclusion, understanding the balance of kinase and phosphatase activities in DSBs repair provides opportunities for the development of novel cancer therapeutics.

Polo-like kinase 1 (PLK1) O-GlcNAcylation is essential for dividing mammalian cells and inhibits uterine carcinoma

The O-linked β-N-acetylglucosamine (O-GlcNAc) transferase (OGT) mediates intracellular O-GlcNAcylation modification. O-GlcNAcylation occurs on Ser/Thr residues and is important for numerous physiological processes. OGT is essential for dividing mammalian cells and is involved in many human diseases; however, many of its fundamental substrates during cell division remain unknown. Here, we focus on the effect of OGT on polo-like kinase 1 (PLK1), a mitotic master kinase that governs DNA replication, mitotic entry, chromosome segregation, and mitotic exit. We show that PLK1 interacts with OGT and is O-GlcNAcylated. By utilizing stepped collisional energy/higher-energy collisional dissociation mass spectrometry, we found a peptide fragment of PLK1 that is modified by O-GlcNAc. Further mutation analysis of PLK1 shows that the T291A mutant decreases O-GlcNAcylation. Interestingly, T291N is a uterine carcinoma mutant in The Cancer Genome Atlas. Our biochemical assays demonstrate that T291A and T291N both increase PLK1 stability. Using stable H2B-GFP cells, we found that PLK1-T291A and PLK1-T291N mutants display chromosome segregation defects and result in misaligned and lagging chromosomes. In mouse xenograft models, we demonstrate that the O-GlcNAc-deficient PLK1-T291A and PLK1-T291N mutants enhance uterine carcinoma in animals. Hence, we propose that OGT partially exerts its mitotic function through O-GlcNAcylation of PLK1, which might be one mechanism by which elevated levels of O-GlcNAc promote tumorigenesis.

Contribution of integrin adhesion to cytokinetic abscission and genomic integrity

Recent research shows that integrin-mediated adhesion contributes to the regulation of cell division at two key steps: the formation of the mitotic spindle at the mitotic entry and the final cytokinetic abscission at the mitotic exit. Failure in either of these processes will have a direct impact on the other in each round of the cell cycle and on the genomic integrity. This review aims to present how integrin signals are involved at these cell cycle stages under normal conditions and some safety mechanisms that may counteract the generation of aneuploid cells in cases of defective integrin signals.

The anaphase-promoting complex/cyclosome co-activator, Cdh1, is a novel target of human papillomavirus 16 E7 oncoprotein in cervical oncogenesis

The transforming properties of the high-risk human papillomavirus (HPV) E7 oncoprotein are indispensable for driving the virus life cycle and pathogenesis. Besides inactivation of the retinoblastoma family of tumor suppressors as part of its oncogenic endeavors, E7-mediated perturbations of eminent cell cycle regulators, checkpoint proteins and proto-oncogenes are considered to be the tricks of its transformative traits. However, many such critical interactions are still unknown. In the present study, we have identified the anaphase-promoting complex/cyclosome (APC) co-activator, Cdh1, as a novel interacting partner and a degradation target of E7. We found that HPV16 E7-induced inactivation of Cdh1 promoted abnormal accumulation of multiple Cdh1 substrates. Such a mode of deregulation possibly contributes to HPV-mediated cervical oncogenesis. Our mapping studies recognized the C-terminal zinc-finger motif of E7 to associate with Cdh1 and interfere with the timely degradation of FoxM1, a bona fide Cdh1 substrate and a potent oncogene. Importantly, the E7 mutant with impaired interaction with Cdh1 exhibited defects in its ability for overriding typical cell cycle transition and oncogenic transformation, thereby validating the functional and pathological significance of the E7-Cdh1 axis during cervical carcinoma progression. Altogether, the findings from our study discover a unique nexus between E7 and APC/C-Cdh1, thereby adding to our understanding of the mechanism of E7-induced carcinogenesis and provide a promising target for the management of cervical carcinoma.

PLK1 as one novel target for the poor prognosis of bladder cancer: An observational study

Bladder cancer (BC) is one of the most common male malignant tumors and the most common urological tumor. However, the molecular mechanism and role of PLK1 on bladder cancer were unclear. Therefore, the study aims to explore the potential part of the overall survival of bladder cancer through bioinformatics analysis. GSE121711 and GSE130598, from the Gene Expression Omnibus database. The GEO2R screened differently expressed genes, and DAVID and Metascape were used for functional annotation. The cytoHubba made hub genes identification and expression. A total of 50 BC participants were recruited. After surgery, 50 BC tumor samples from BC patients and 50 adjacent standard bladder tissue samples were obtained. The RT-qPCR assay was performed to verify the expression of hub genes. The Kaplan-Meier Plotter analyzed the effect of hub gene expression for overall survival of BC. The compulsory module of Molecular Complex Detection tool analysis was shown, which included CDK1, TTK, AURKB, MELK, PLK1, and BUB1. And the six hub genes were up-regulated in the BC compared with the normal tissues. The relative expression levels of CDK1, TTK, AURKB, MELK, PLK1, and BUB1 were significantly higher in BC samples compared with the regular kidney tissue groups. The result demonstrated that CDK1, TTK, AURKB, MELK, PLK1, and BUB1 might be considered biomarkers for BC. Overall survival analysis showed that BC patients with high expression level of PLK1 had poorer overall survival times than those with low expression level (P < .05). The expression levels of CDK1, TTK, AURKB, MELK, and BUB1 was not related to the overall survival of BC patients (P > .05). The PLK1 gene might provide new ideas and evidence for bladder cancer research.

CDK7/GRP78 signaling axis contributes to tumor growth and metastasis in osteosarcoma

Osteosarcoma derives from primitive bone-forming mesenchymal cells and is the most common primary bone malignancy. Therapeutic targeting of osteosarcoma has been unsuccessful; therefore, identifying novel osteosarcoma pathogenesis could offer new therapeutic options. CDK7 is a subunit within the general transcription factor TFIIH. We aim to explore the new mechanism by which CDK7 regulates osteosarcoma and our studies may provide new theoretical support for the use of CDK7 inhibitors in the treatment of osteosarcoma. Here, we investigate the molecular mechanism underlying the association between CDK7 and GRP78 in osteosarcoma. Specifically, we find that an E3 ubiquitin ligase TRIM21 binds and targets GRP78 for ubiquitination and degradation, whereas CDK7 phosphorylates GRP78 at T69 to inhibit TRIM21 recruitment, leading to GRP78 stabilization. Notably, a CDK7-specific inhibitor, THZ1, blunts osteosarcoma growth and metastasis. Combination treatment with CDK7 and GRP78 inhibitors yield additive effects on osteosarcoma growth and progression inhibition. Thus, simultaneous suppression of CDK7 and GRP78 activity represents a potential new approach for the treatment of osteosarcoma. In conclusion, the discovery of this previously unknown CDK7/GRP78 signaling axis provides the molecular basis and the rationale to target human osteosarcoma.

FANCI may serve as a prognostic biomarker for cervical cancer: A systematic review and meta-analysis

BACKGROUND

DNA damage is a fundamental process that plays a considerable role in generating protein diversity. FANCI, loaded on the altered chromatin, plays a vital role in DNA damage. Abnormal FANCI expression is potentially associated with carcinogenesis.However, the biological role of FANCI in cervical cancer is yet to be determined.

METHODS

We analyzed FANCI expression via multiple gene expression databases. Genes co-expressed with FANCI and its regulators were identified using LinkedOmics. The correlations between FANCI and cancer immune infiltrates were investigated via Tumor Immune Estimation Resource (TIMER).

RESULTS

FANCI was found upregulated with amplification in tumor tissues of multiple cervical cancer cohorts. High FANCI expression was associated with poorer overall survival (OS). Functional network analysis suggested that FANCI regulates spliceosome, DNA replication, and cell cycle signaling via pathways involving several cancer-related kinases and the E2F family. In additional, FANCI expression was positively correlated with infiltrating levels of CD4+ T and CD8+ T cells, and neutrophils. FANCI expression also showed strong correlations with diverse immune marker sets in cervical cancer.

CONCLUSION

These findings suggested that FANCI is correlated with prognosis of and immune infiltration in cervical cancer, laying a foundation for further study of the immune regulatory role of FANCI in cervical cancer.

Molecular Markers to Predict Prognosis and Treatment Response in Uterine Cervical Cancer

Uterine cervical cancer is one of the leading causes of cancer-related mortality in women worldwide. Each year, over half a million new cases are estimated, resulting in more than 300,000 deaths. While less-invasive, fertility-preserving surgical procedures can be offered to women in early stages, treatment for locally advanced disease may include radical hysterectomy, primary chemoradiotherapy (CRT) or a combination of these modalities. Concurrent platinum-based chemoradiotherapy regimens remain the first-line treatments for locally advanced cervical cancer. Despite achievements such as the introduction of angiogenesis inhibitors, and more recently immunotherapies, the overall survival of women with persistent, recurrent or metastatic disease has not been extended significantly in the last decades. Furthermore, a broad spectrum of molecular markers to predict therapy response and survival and to identify patients with high- and low-risk constellations is missing. Implementation of these markers, however, may help to further improve treatment and to develop new targeted therapies. This review aims to provide comprehensive insights into the complex mechanisms of cervical cancer pathogenesis within the context of molecular markers for predicting treatment response and prognosis.

Bioinformatics screening of biomarkers related to liver cancer

Background

Liver cancer is a common malignant tumor in China, with high mortality. Its occurrence and development were thoroughly studied by high-throughput expression microarray, which produced abundant data on gene expression, mRNA quantification and the clinical data of liver cancer. However, the hub genes, which can be served as biomarkers for diagnosis and treatment of early liver cancer, are not well screened.

Results

Here we present a new method for getting 6 key genes, aiming to diagnose and treat the early liver cancer. We firstly analyzed the different expression microarrays based on TCGA database, and a total of 1564 differentially expressed genes were obtained, of which 1400 were up-regulated and 164 were down-regulated. Furthermore, these differentially expressed genes were studied by using GO and KEGG enrichment analysis, a PPI network was constructed based on the STRING database, and 15 hub genes were obtained. Finally, 15 hub genes were verified by applying the survival analysis method on Oncomine database, and 6 key genes were ultimately identified, including PLK1, CDC20, CCNB2, BUB1, MAD2L1 and CCNA2. The robustness analysis of four independent data sets verifies the accuracy of the key gene’s classification of the data set.

Conclusions

Although there are complicated differences between cancer and normal cells in gene functions, cancer cells could be differentiated in case that a group of special genes expresses abnormally. Here we presented a new method to identify the 6 key genes for diagnosis and treatment of early liver cancer, and these key genes can help us understand the pathogenesis of liver cancer more deeply.

Role of the ABL tyrosine kinases in the epithelial-mesenchymal transition and the metastatic cascade

The ABL kinases, ABL1 and ABL2, promote tumor progression and metastasis in various solid tumors. Recent reports have shown that ABL kinases have increased expression and/or activity in solid tumors and that ABL inactivation impairs metastasis. The therapeutic effects of ABL inactivation are due in part to ABL-dependent regulation of diverse cellular processes related to the epithelial to mesenchymal transition and subsequent steps in the metastatic cascade. ABL kinases target multiple signaling pathways required for promoting one or more steps in the metastatic cascade. These findings highlight the potential utility of specific ABL kinase inhibitors as a novel treatment paradigm for patients with advanced metastatic disease. Video abstract.

Synergistic Therapy for Cervical Cancer by Codelivery of Cisplatin and JQ1 Inhibiting Plk1-Mutant Trp53 Axis

JQ1, a specific inhibitor of bromodomain-containing protein 4 (BRD4), could have great potential in the treatment of cervical cancer. However, its clinical application is limited by its short plasma half-life and limited antitumor efficacy. In this work, cisplatin (CDDP) was first utilized as the stabilizer and cooperator in the nanosystem (mPEG₁₁₃-b-P(Glu₁₀-co-Phe₁₀)-CDDP/JQ1, called PGP-CDDP/JQ1) to break through the efficiency limitation of JQ1. The PGP-CDDP/JQ1 had a combination index (CI) of 0.21, exerting a strong cytotoxic synergistic effect. In vivo experiments revealed that PGP-CDDP/JQ1 had a significantly higher tumor inhibition effect (tumor inhibition rate: 85% vs 14%) and plasma stability of JQ1 (area under the curve (AUC_0-∞): 335.97 vs 16.88 μg × h/mL) than free JQ1. The mechanism underling the synergism of JQ1 with CDDP in PGP-CDDP/JQ1 was uncovered to be inhibiting Plk1-mutant Trp53 axis. Thus, this study provides an optional method for improving the clinical application of JQ1 in cervical cancer.

Polo like kinase 1 expression in cervical cancer tissues generated from multiple detection methods

Background

Existing studies of PLK1 in cervical cancer had several flaws. The methods adopted by those studies of detecting PLK1 expression in cervical cancer were single and there lacks comprehensive evaluation of the clinico-pathological significance of PLK1 in cervical cancer.

Methods

A total of 303 cervical tissue samples were collected for in-house tissue microarrays. Immunohistochemistry was performed for evaluating PLK1 expression between cervical cancer (including cervical squamous cell carcinoma (CESC) and cervical adenocarcinoma) and non-cancer samples. The Expression Atlas database was searched for querying PLK1 expression in different cervical cancer cell lines and different tissues in the context of pan-cancer. Standard mean difference (SMD) was calculated and the summarized receiver's operating characteristics (SROC) curves were plotted for integrated tissue microarrays, exterior high-throughput microarrays and RNA sequencing data as further verification. The effect of PLK1 expression on the overall survival, disease-free survival and event-free survival of cervical cancer patients was analyzed through Kaplan Meier survival curves for cervical cancer patients from RNA-seq and GSE44001 datasets. The gene mutation and alteration status of PLK1 in cervical cancer was inspected in COSMIC and cBioPortal databases. Functional enrichment analysis was performed for genes correlated with PLK1 from aggregated RNA-seq and microarrays.

Results

A total of 963 cervical cancer samples and 178 non-cancer samples were collected from in-house tissue microarrays and exterior microarrays and RNA-seq datasets. The combined expression analysis supported overexpression of PLK1 in CESC, cervical adenocarcinoma and all types of cervical cancer (SMD = 1.59, 95%CI [0.56-2.63]; SMD = 2.99, 95%CI [0.75-5.24]; SMD = 1.57, 95% CI [0.85-2.29]) and the significant power of PLK1 expression in distinguishing CESC or all types of cervical cancer samples from non-cancer samples (AUC = 0.94, AUC = 0.92). Kaplan-Meier survival curves showed that the event-free survival rate of cervical cancer patients with higher expression of PLK1 was shorter than that of patients with lower PLK1 (HR = 2.020, P = 0.0197). Genetic alteration of PLK1 including missense mutation and mRNA low occurred in 6% of cervical cancer samples profiled in mRNA expression. Genes positively or negatively correlated with PLK1 were mainly assembled in pathways such as DNA replication, cell cycle, mismatch repair, Ras signaling pathway, melanoma, EGFR tyrosine kinase inhibitor resistance and homologous recombination (P < 0.05).

Conclusions

Here, we provided sufficient evidence of PLK1 overexpression in cervical cancer. The overexpression of PLK1 in cervical cancer and the contributory effect of it on clinical progression indicated the hopeful prospect of PLK1 as a biomarker for cervical cancer.

Analyses of expressions and prognostic values of Polo-like kinases in non-small cell lung cancer

BACKGROUND

Despite great advances in its early diagnosis and treatment, lung cancer is still an intractable disease and the second leading cause of cancer-related deaths and morbidity in the world. The family of Polo-like kinases (PLKs) consists of five serine/threonine kinases, which have been reported to participate in various human diseases. However, the expression and prognostic value of each PLK in human lung cancer have not been fully understood. This study analyzed mRNA expression and prognostic value of different PLKs in human non-small cell lung cancer (NSCLC).

METHODS

First, mRNA expression of PLKs in patients with NSCLC from the Oncomine and the Gene Expression Profiling Interactive Analysis (GEPIA) database was investigated. Then, a Kaplan-Meier plotter was employed for survival analysis. The sequence alteration for PLKs was analyzed using The Cancer Genome Atlas (TCGA) and the cBioPortal database. Additionally, we analyzed the association among different PLKs using the LinkedOmics database. Finally, the enrichment analysis of PLKs was achieved using the DAVID database.

RESULTS

The mRNA expression levels of PLK1 and PLK4 were significantly overexpressed, while mRNA expression level of PLK3 was underexpressed in patients with NSCLC. mRNA expressions of PLK1 and PLK4 were significantly and positively related to the tumor stage of NSCLC. Increased expressions of PLK1, PLK4, and PLK5 and decreased expression of PLK2 were attributed to limited overall survival time in NSCLC. PLK1 was positively correlated with PLK4 via the LinkedOmics database.

CONCLUSIONS

PLKs are relevant targets for NSCLC treatment, especially PLK1 and PLK4.

Analysis of deubiquitinase OTUD5 as a biomarker and therapeutic target for cervical cancer by bioinformatic analysis

OTU deubiquitinase 5 (OTUD5), as a member of the ovarian tumor protease (OTU) family, was previously reported to play important roles in DNA repair and immunity. However, little is known about its function in tumors. Cervical cancer is a malignant tumor that seriously endangers the lives of women. Here, we found that low expression of OTUD5 in cervical cancer is associated with poor prognosis. Its expression is associated with tumor stage, metastatic nodes and tumor subtypes such as those related to the phosphatidylinositol–3–kinase (PI3K)–AKT signaling, epithelial-mesenchymal transition (EMT) and hormones. In addtion, we analyzed the coexpressed genes, related miRNAs, transcription factors, kinases, E3s and interacting proteins of OTUD5. We demonstrated that OTUD5 affects the expression levels of WD repeat domain 45 (WDR45), ubiquitin-specific peptidase 11 (USP11), GRIP1 associated protein 1 (GRIPAP1) and RNA binding motif protein 10 (RBM10). Moreover, hsa-mir-137, hsa-mir-1913, hsa-mir-937, hsa-mir-607, hsa-mir-3149 and hsa-mir-144 may inhibit the expression of OTUD5. Furthermore, we performed enrichment analysis of 22 coexpressed genes, 33 related miRNAs and 30 interacting proteins. In addition to ubiquitination and immunology related processes, they also participate in Hippo signaling, insulin signaling, EMT, histone methylation and phosphorylation kinase binding. Our study for the first time analyzed the expression of OTUD5 in cervical cancer and its relationship with clinicopathology and provided new insights for further study of its regulatory mechanism in tumors.

Identification of hub genes in hepatocellular carcinoma using integrated bioinformatic analysis

The molecular mechanisms underlying hepatocellular carcinoma (HCC) progression remain largely undefined. Here, we identified 176 commonly upregulated genes in HCC tissues based on three Gene Expression Omnibus datasets and The Cancer Genome Atlas (TCGA) cohort. We integrated survival and methylation analyses to further obtain 12 upregulated genes for validation. These genes were overexpressed in HCC tissues at the transcription and protein levels, and increased mRNA levels were related to higher tumor grades and cancer stages. The expression of all markers was negatively associated with overall and disease-free survival in HCC patients. Most of these hub genes can promote HCC proliferation and/or metastasis. These 12 hub genes were also overexpressed and had strong prognostic value in many other cancer types. Methylation and gene copy number analyses indicated that the upregulation of these hub genes was probably due to hypomethylation or increased gene copy numbers. Further, the methylation levels of three genes, KPNA2, MCM3, and LRRC1, were associated with HCC clinical features. Moreover, the levels of most hub genes were related to immune cell infiltration in HCC microenvironments. Finally, we identified three upregulated genes (KPNA2, TARBP1, and RNASEH2A) that could comprehensively and accurately provide diagnostic and prognostic value for HCC patients.

Systematic expression analysis of WEE family kinases reveals the importance of PKMYT1 in breast carcinogenesis

OBJECTIVES

Many cancer cells depend on G2 checkpoint mechanism regulated by WEE family kinases to maintain genomic integrity. The PKMYT1 gene, as a member of WEE family kinases, participates in G2 checkpoint surveillance and probably links with tumorigenesis, but its role in breast cancer remains largely unclear.

MATERIALS AND METHODS

In this study, we used a set of bioinformatic tools to jointly analyse the expression of WEE family kinases and investigate the prognostic value of PKMYT1 in breast cancer.

RESULTS

The results indicated that PKMYT1 is the only frequently overexpressed member of WEE family kinases in breast cancer. KM plotter data suggests that abnormally high expression of PKMYT1 predicts poor prognosis, especially for some subtypes, such as luminal A/B and triple-negative (TNBC) types. Moreover, the up-regulation of PKMYT1 was associated with HER2-positive (HER2+), basal-like (Basal-like), TNBC statuses and increased classifications of Scarff, Bloom and Richardson (SBR). Co-expression analysis showed PKMYT1 has a strong positive correlation with Polo-like kinase 1 (PLK1), implying they may cooperate in regulating cancer cell proliferation by synchronizing rapid cell cycle with high quality of genome maintenance.

CONCLUSIONS

Collectively, this study demonstrates that overexpression of PKMYT1 is always found in breast cancer and predicts unfavourable prognosis, implicating it as an appealing therapeutic target for breast carcinoma.

ERK Regulates HIF1α-Mediated Platinum Resistance by Directly Targeting PHD2 in Ovarian Cancer

PURPOSE

Up to 80% of patients with ovarian cancer develop platinum resistance over time to platinum-based chemotherapy. Increased HIF1α level is an important mechanism governing platinum resistance in platinum-resistant ovarian cancer (PROC). However, the mechanism regulating HIF1α stability in PROC remains largely unknown. Here, we elucidate the mechanism of HIF1α stability regulation in PROC and explore therapeutic approaches to overcome cisplatin resistance in ovarian cancer.

EXPERIMENTAL DESIGN

We first used a quantitative high-throughput combinational screen (qHTCS) to identify novel drugs that could resensitize PROC cells to cisplatin. Next, we evaluated the combination efficacy of inhibitors of HIF1α (YC-1), ERK (selumetinib), and TGFβ1 (SB431542) with platinum drugs by in vitro and in vivo experiments. Moreover, a novel TGFβ1/ERK/PHD2-mediated pathway regulating HIF1α stability in PROC was discovered.

RESULTS

YC-1 and selumetinib resensitized PROC cells to cisplatin. Next, the prolyl hydroxylase domain-containing protein 2 (PHD2) was shown to be a direct substrate of ERK. Phosphorylation of PHD2 by ERK prevents its binding to HIF1α, thus inhibiting HIF1α hydroxylation and degradation-increasing HIF1α stability. Significantly, ERK/PHD2 signaling in PROC cells is dependent on TGFβ1, promoting platinum resistance by stabilizing HIF1α. Inhibition of TGFβ1 by SB431542, ERK by selumetinib, or HIF1α by YC-1 efficiently overcame platinum resistance both in vitro and in vivo. The results from clinical samples confirm activation of the ERK/PHD2/HIF1α axis in patients with PROC, correlating highly with poor prognoses for patients.

CONCLUSIONS

HIF1α stabilization is regulated by TGFβ1/ERK/PHD2 axis in PROC. Hence, inhibiting TGFβ1, ERK, or HIF1α is potential strategy for treating patients with PROC.

Crinamine Induces Apoptosis and Inhibits Proliferation, Migration, and Angiogenesis in Cervical Cancer SiHa Cells

Crinum asiaticum is a perennial herb widely distributed in many warmer regions, including Thailand, and is well-known for its medicinal and ornamental values. Crinum alkaloids contain numerous compounds, such as crinamine. Even though its mechanism of action is still unknown, crinamine was previously shown to possess anticancer activity. In this study, we demonstrate that crinamine was more cytotoxic to cervical cancer cells than normal cells. It also inhibited anchorage-independent tumor spheroid growth more effectively than existing chemotherapeutic drugs carboplatin and 5-fluorouracil or the CDK9 inhibitor FIT-039. Additionally, unlike cisplatin, crinamine induced apoptosis without promoting DNA double-strand breaks. It suppressed cervical cancer cell migration by inhibiting the expression of positive regulators of epithelial-mesenchymal transition SNAI1 and VIM. Importantly, crinamine also exerted anti-angiogenic activities by inhibiting secretion of VEGF-A protein in cervical cancer cells and blood vessel development in zebrafish embryos. Gene expression analysis revealed that its mechanism of action might be attributed, in part, to downregulation of cancer-related genes, such as AKT1, BCL2L1, CCND1, CDK4, PLK1, and RHOA. Our findings provide a first insight into crinamine's anticancer activity, highlighting its potential use as an alternative bioactive compound for cervical cancer chemoprevention and therapy.

Potent antiproliferative effect of fatty-acid derivative AIC-47 on leukemic mice harboring BCR-ABL mutation

Therapy based on targeted inhibition of BCR‐ABL tyrosine kinase has greatly improved the prognosis for patients with Philadelphia chromosome (Ph)‐positive leukemia and tyrosine kinase inhibitors (TKI) have become standard therapy. However, some patients acquire resistance to TKI that is frequently associated with point mutations in BCR‐ABL. We previously reported that a medium‐chain fatty‐acid derivative AIC‐47 induced transcriptional suppression of BCR‐ABL and perturbation of the Warburg effect, leading to growth inhibition in Ph‐positive leukemia cells. Herein, we showed that AIC‐47 had anti‐leukemic effects in either wild type (WT)‐ or mutated‐BCR‐ABL‐harboring cells. AIC‐47 suppressed transcription of BCR‐ABL gene regardless of the mutation through downregulation of transcriptional activator, c‐Myc. Reprogramming of the metabolic pathway has been reported to be associated with resistance to anti‐cancer drugs; however, we found that a point mutation of BCR‐ABL was independent of the profile of pyruvate kinase muscle (PKM) isoform expression. Even in T315I‐mutated cells, AIC‐47 induced switching of the expression profile of PKM isoforms from PKM2 to PKM1, suggesting that AIC‐47 disrupted the Warburg effect. In a leukemic mouse model, AIC‐47 greatly suppressed the increase in BCR‐ABLmRNA level and improved hepatosplenomegaly regardless of the BCR‐ABL mutation. Notably, the improvement of splenomegaly by AIC‐47 was remarkable and might be equal to or greater than that of TKI. These findings suggest that AIC‐47 might be a promising agent for overcoming the resistance of Ph‐positive leukemia to therapy.

Cyclin B2 Overexpression in Human Hepatocellular Carcinoma is Associated with Poor Prognosis

BACKGROUND AND AIMS

Cyclin B2 (CCNB2) has been reported to be highly expressed in a few malignancies. However, the biological function of CCNB2 in hepatocellular carcinoma (HCC) is largely unknown. We aimed to investigate the effect of CCNB2 in HCC.

METHODS

The expression of CCNB2 in HCC and normal liver tissues and connection of its expression with prognosis and clinical parameters were studied. The effect of knocking down CCNB2 on cell proliferation, migration, cell cycle distribution, and apoptosis were estimated in BEL-7404 cells.

RESULTS

Compared to normal liver tissues, the level of CCNB2 was higher in HCC tissues from the Gene Expression Profiling Interactive Analysis (GEPIA). The 5 year overall survival and disease-free survival of HCC patients with high CCNB2 levels were shorter than that of those with low CCNB2 levels. Immunohistochemistry analysis also discovered the expression differences of CCNB2 in HCC and normal liver tissues and showed that CCNB2 expression was significantly associated with tumor number, tumor size, tumor thrombus, and alanine aminotransferase level. CCNB2 expression was higher in HCC cell lines (BEL-7404, Hep3B, BEL-7402, and SMMC-7721) than that in the normal hepatic cell line (HL-7702). Knockdown of CCNB2 inhibited cell proliferation and migration, promoted cell apoptosis, and caused S phase arrest in BEL-7404 cells. Finally, CCNB2 was associated with Polo Like Kinase 1 (PLK1) in the GEPIA database and BEL-7404 cells.

CONCLUSIONS

CCNB2 may serve as a prognostic factor and participated in the development and progression and promote cell proliferation and migration through CCNB2/PLK1 pathway in HCC.

EnABLing Tumor Growth and Progression: Recent progress in unraveling the functions of ABL kinases in solid tumor cells

PURPOSE OF REVIEW

The goal of this review is to summarize our current knowledge regarding how ABL family kinases are activated in solid tumors and impact on solid tumor development/progression, with a focus on recent advances in the field.

RECENT FINDINGS

Although ABL kinases are known drivers of human leukemia, emerging data also implicates the kinases in a large number of solid tumor types where they promote diverse processes such as proliferation, survival, cytoskeletal reorganization, cellular polarity, EMT (epithelial-mesenchymal-transition), metabolic reprogramming, migration, invasion and metastasis via unique signaling pathways. ABL1 and ABL2 appear to have overlapping but also unique roles in driving these processes. In some tumor types, the kinases may act to integrate pro- and anti-proliferative and -invasive signals, and also may serve as a switch during EMT/MET (mesenchymal-epithelial) transitions.

CONCLUSIONS

Most data indicate that targeting ABL kinases may be effective for reducing tumor growth and preventing metastasis; however, ABL kinases also may have a tumor suppressive role in some tumor types and in some cellular contexts. Understanding the functions of ABL kinases in solid tumors is critical for developing successful clinical trials aimed at targeting ABL kinases for the treatment of solid tumors.