Dual targeting of Polo-like kinase 1 and baculoviral inhibitor of apoptosis repeat-containing 5 in TP53-mutated hepatocellular carcinoma

Fatty acid binding protein 5 is a novel therapeutic target for hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is an aggressive subtype of liver cancer and is one of the most common cancers with high mortality worldwide. Reprogrammed lipid metabolism plays crucial roles in HCC cancer cell survival, growth, and evolution. Emerging evidence suggests the importance of fatty acid binding proteins (FABPs) in contribution to cancer progression and metastasis; however, how these FABPs are dysregulated in cancer cells, especially in HCC, and the roles of FABPs in cancer progression have not been well defined.

AIM

To understand the genetic alterations and expression of FABPs and their associated cancer hallmarks and oncogenes in contributing to cancer malignancies.

METHODS

We used The Cancer Genome Atlas datasets of pan cancer and liver hepatocellular carcinoma (LIHC) as well as patient cohorts with other cancer types in this study. We investigated genetic alterations of FABPs in various cancer types. mRNA expression was used to determine if FABPs are abnormally expressed in tumor tissues compared to non-tumor controls and to investigate whether their expression correlates with patient clinical outcome, enriched cancer hallmarks and oncogenes previously reported for patients with HCC. We determined the protein levels of FABP5 and its correlated genes in two HCC cell lines and assessed the potential of FABP5 inhibition in treating HCC cells.

RESULTS

We discovered that a gene cluster including five FABP family members (FABP4, FABP5, FABP8, FABP9 and FABP12) is frequently co-amplified in cancer. Amplification, in fact, is the most common genetic alteration for FABPs, leading to overexpression of FABPs. FABP5 showed the greatest differential mRNA expression comparing tumor with non-tumor tissues. High FABP5 expression correlates well with worse patient outcomes (P < 0.05). FABP5 expression highly correlates with enrichment of G2M checkpoint (r = 0.33, P = 1.1e-10), TP53 signaling pathway (r = 0.22, P = 1.7e-5) and many genes in the gene sets such as CDK1 (r = 0.56, P = 0), CDK4 (r = 0.49, P = 0), and TP53 (r = 0.22, P = 1.6e-5). Furthermore, FABP5 also correlates well with two co-expressed oncogenes PLK1 and BIRC5 in pan cancer especially in LIHC patients (r = 0.58, P = 0; r = 0.58, P = 0; respectively). FABP5high Huh7 cells also expressed higher protein levels of p53, BIRC5, CDK1, CDK2, and CDK4 than FABP5low HepG2 cells. FABP5 inhibition more potently inhibited the tumor cell growth in Huh7 cells than in HepG2 cells.

CONCLUSION

We discovered that FABP5 gene is frequently amplified in cancer, especially in HCC, leading to its significant elevated expression in HCC. Its high expression correlates well with worse patient outcome, enriched cancer hallmarks and oncogenes in HCC. FABP5 inhibition impaired the cell viability of FABP5high Huh7 cells. All these support that FABP5 is a novel therapeutic target for treating FABP5high HCC.

Prognostic and immunological roles of heat shock protein A4 in lung adenocarcinoma

BACKGROUND

Heat shock protein A4 (HSPA4) belongs to molecular chaperone protein family which plays important roles within variable cellular activities, including cancer initiation and progression. However, the prognostic and immunological significance of HSPA4 in lung adenocarcinoma (LUAD) has not been revealed yet.

AIM

To explore the prognostic and immunological roles of HSPA4 to identify a novel prognostic biomarker and therapeutic target for LUAD.

METHODS

We assessed the prognostic and immunological significance of HSPA4 in LUAD using data from The Cancer Genome Atlas database. The association between HSPA4 expression and clinical-pathological features was assessed through Kruskal-Wallis and Wilcoxon signed-rank test. Univariate/multivariate Cox regression analyses and Kaplan-Meier curves were employed to evaluate prognostic factors, including HSPA4, in LUAD. Gene set enrichment analysis (GSEA) was conducted to identify the key signaling pathways associated with HSPA4. The correlation between HSPA4 expression and cancer immune infiltration was evaluated using single-sample gene set enrichment analysis (ssGSEA).

RESULTS

Overexpressing HSPA4 was significantly related to advanced pathologic TNM stage, advanced pathologic stage, progression disease status of primary therapy outcome and female subgroups with LUAD. In addition, increased HSPA4 expression was found to be related to worse disease-specific survival and overall survival. GSEA analysis indicated a significant correlation between HSPA4 and cell cycle regulation and immune response, particularly through diminishing the function of cytotoxicity cells and CD8 T cells. The ssGSEA algorithm showed a positive correlation between HSPA4 expression and infiltrating levels of Th2 cells, while a negative correlation was observed with cytotoxic cell infiltration levels.

CONCLUSION

Our findings indicate HSPA4 is related to prognosis and immune cell infiltrates and may act as a novel prognostic biomarker and therapeutic target for LUAD.

Combined Inhibition of UBE2C and PLK1 Reduce Cell Proliferation and Arrest Cell Cycle by Affecting ACLY in Pan-Cancer

Various studies have shown that the cell-cycle-related regulatory proteins UBE2C, PLK1, and BIRC5 promote cell proliferation and migration in different types of cancer. However, there is a lack of in-depth and systematic research on the mechanism of these three as therapeutic targets. In this study, we found a positive correlation between the expression of UBE2C and PLK1/BIRC5 in the Cancer Genome Atlas (TCGA) database, revealing a potential combination therapy candidate for pan-cancer. Quantitative real-time PCR (qRT-PCR), Western blotting (WB), cell phenotype detection, and RNA-seq techniques were used to evidence the effectiveness of the combination candidate. We found that combined interference of UBE2C with PLK1 and UBE2C with BIRC5 affected metabolic pathways by significantly downregulating the mRNA expression of IDH1 and ACLY, which was related to the synthesis of acetyl-CoA. By combining the PLK1 inhibitor volasertib and the ACLY inhibitor bempedoic acid, it showed a higher synergistic inhibition of cell viability and higher synergy scores in seven cell lines, compared with those of other combination treatments. Our study reveals the potential mechanisms through which cell-cycle-related genes regulate metabolism and proposes a potential combined targeted therapy for patients with higher PLK1 and ACLY expression in pan-cancer.

A novel association of pyroptosis-related gene signature with the prognosis of hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the global leading lethal tumors. Pyroptosis has recently been defined as an inflammatory programmed cell death, which is closely linked to cancer progression. However, the significance of pyroptosis-related genes (PRGs) in the prognosis of HCC remains elusive.

Methods

RNA sequencing (RNA-seq) data of HCC cases and their corresponding clinical information were collected from the Cancer Genome Atlas (TCGA) database, and differential PRGs were explored. The prognostic PRGs were analyzed with univariate COX regression and the least absolute shrinkage and selection operator (LASSO) Cox regression analysis to build a prognostic model in the TCGA training cohort. The predictive model was further validated in the TCGA test cohort and ICGC validation cohort. Differential gene function and associated pathway analysis were performed by Gene ontology (GO) and Kyoto Encyclopedia of Gene and Genomes (KEGG). Single-sample gene set enrichment analysis (ssGSEA) was used to identify distinct immune cell infiltration. The mRNA and protein expression of prognostic PRGs was examined by quantitative RT-qPCR and immunohistochemistry.

Results

We identified 46 PRGs that were differentially expressed between normal and HCC tissues in a TCGA cohort, and HCC patients could be well categorized into two clusters associated with distinct survival rates based on expression levels of the PRGs. A three-PRG prognostic model comprising CHMP4A, HMGB1 and PLK1 was constructed in the training cohort, and HCC patients could be classified into the high- and low-risk subgroups based on the median risk score. High-risk patients exhibited shorter overall survival (OS) than low-risk ones, which was validated in the test cohort and ICGC validation cohort. The risk score of this model was confirmed as an independent prognostic factor to predict OS of HCC patients. GO, KEGG and ssGSEA demonstrated the differential immune cell infiltrations were associated with the risk scores. The higher expression of CHMP4A, HMGB1 and PLK1 were validated in HCC compared to normal in vivo and in vitro.

Conclusion

The three-PRG signature (CHMP4A, HMGB1, and PLK1) could act as an independent factor to predict the prognosis of HCC patients, which would shed light upon a potent therapeutic strategy for HCC treatment.

Mechanisms of carcinogenic activity triggered by lysine-specific demethylase 1A

Epigenetics has emerged as a prime focus area in the field of cancer research. Lysine-specific demethylase 1A (LSD1), the first discovered histone demethylase, is mainly responsible for catalysing demethylation of histone 3 lysine 4 (H3K4) and H3K9 to activate or inhibit gene transcription. LSD1 is abnormally expressed in various cancers and participates in cancer proliferation, apoptosis, metastasis, invasion, drug resistance and other processes by interacting with regulatory factors. Therefore, it may serve as a potential therapeutic target for cancer. This review summarises the major oncogenic mechanisms mediated by LSD1 and provides a reference for developing novel and efficient anticancer strategies targeting LSD1.

PLK1 inhibition-based combination therapies for cancer management

Polo-like kinase I (PLK1), a cell cycle regulating kinase, has been shown to have oncogenic function in several cancers. Although PLK1 inhibitors, such as BI2536, BI6727 (volasertib) and NMS-1286937 (onvansertib) are generally well-tolerated with a favorable pharmacokinetic profile, clinical successes are limited due to partial responses in cancer patients, especially those in advanced stages. Recently, combination therapies targeting multiple pathways are being tested for cancer management. In this review, we first discuss structure and function of PLK1, role of PLK1 in cancers, PLK1 specific inhibitors, and advantages of using combination therapy versus monotherapy followed by a critical account on PLK1-based combination therapies in cancer treatments, especially highlighting recent advancements and challenges. PLK1 inhibitors in combination with chemotherapy drugs and targeted small molecules have shown superior effects against cancer both in vitro and in vivo. PLK1-based combination therapies have shown increased apoptosis, disrupted cell cycle, and potential to overcome resistance in cancer cells/tissues over monotherapies. Further, with successes in preclinical experiments, researchers are validating such approaches in clinical trials. Although PLK1-based combination therapies have achieved initial success in clinical studies, there are examples where they have failed to improve patient survival. Therefore, further research is needed to identify and validate novel biologically informed co-targets for PLK1-based combinatorial therapies. Employing a network-based analysis, we identified potential PLK1 co-targets that could be examined further. In addition, understanding the mechanisms of synergism between PLK1 inhibitors and other agents may lead to a better approach on which agents to pair with PLK1 inhibition for optimum cancer treatment.

Mapping the landscape of synthetic lethal interactions in liver cancer

Almost all the current therapies against liver cancer are based on the "one size fits all" principle and offer only limited survival benefit. Fortunately, synthetic lethality (SL) may provide an alternate route towards individualized therapy in liver cancer. The concept that simultaneous losses of two genes are lethal to a cell while a single loss is non-lethal can be utilized to selectively eliminate tumors with genetic aberrations. Methods: To infer liver cancer-specific SL interactions, we propose a computational pipeline termed SiLi (statistical inference-based synthetic lethality identification) that incorporates five inference procedures. Based on large-scale sequencing datasets, SiLi analysis was performed to identify SL interactions in liver cancer. Results: By SiLi analysis, a total of 272 SL pairs were discerned, which included 209 unique target candidates. Among these, polo-like kinase 1 (PLK1) was considered to have considerable therapeutic potential. Further computational and experimental validation of the SL pair TP53-PLK1 demonstrated that inhibition of PLK1 could be a novel therapeutic strategy specifically targeting those patients with TP53-mutant liver tumors. Conclusions: In this study, we report a comprehensive analysis of synthetic lethal interactions of liver cancer. Our findings may open new possibilities for patient-tailored therapeutic interventions in liver cancer.

Circular RNA ZNF609 promotes the malignant progression of glioma by regulating miR-1224-3p/PLK1 signaling

Objective: Previous studies have demonstrated that circular RNAs (circRNAs) play vital roles in pathological process of various diseases, including tumors. This study aimed at exploring the role and mechanism of circRNA RNA ZNF609 (circ-ZNF609) in the occurrence and development of glioma. Materials and methods: Real-time quantitative PCR (qRT-PCR) was applied to measure the expression of circ-ZNF609, miRNA-1224-3p (miR-1224-3p) and Polo-like kinase 1 (PLK1) in glioma tissues and cell lines. Furthermore, the association between circ-ZNF609 and clinical features of glioma was analyzed. CCK8 assay, EdU assay and Transwell assay were conducted to detect the effect of circ-ZNF609, miR-1224-3p and PLK1 on proliferation, migration and invasion in glioma cells. Then, we investigated the underlying mechanism of circ-ZNF609 by bioinformatics analysis, luciferase reporter assay, RNA immunoprecipitation (RIP), qRT-PCR and western blotting assay. Results: Circ-ZNF609 was confirmed prominently upregulated in glioma. Inhibition of circ-ZNF609 could obviously suppress glioma cell proliferation, migration and invasion, while overexpression of circ-ZNF609 promoted glioma growth and metastasis. In vivo, xenotransplanted tumor model also showed that overexpression of circ-ZNF609 could promote in vivo glioma growth. Mechanistically, circ-ZNF609 could promote PLK1 expression via binding to miR-1224-3p, circ-ZNF609/miR-1224-3p/PLK1 was shown responsible for circ-ZNF609 promoting glioma growth and metastasis. Conclusion: Together, our results revealed that circ-ZNF609 elevates glioma growth and metastasis via enforcing PLK1 expression by competitively binding miR-1224-3p, suggesting that circ-ZNF609 might be an underlying therapeutic target for glioma.