Actinin-4 protein overexpression as a predictive biomarker in adjuvant chemotherapy for resected lung adenocarcinoma

A novel disulfidptosis-related prognostic gene signature and experimental validation identify ACTN4 as a novel therapeutic target in lung adenocarcinoma

BACKGROUND

Lung adenocarcinoma (LUAD) is a prevalent form of malignancy globally. Disulfidptosis is novel programmed cell death pathway based on disulfide proteins, may have a positive impact on the development of LUAD treatment strategies.

OBJECTIVE

To investigate the impact of disulfidptosis-related genes (DRGs) on the prognosis of LUAD, developed a risk model to facilitate the diagnosis and prognostication of patients. We also explored ACTN4 (DRGs) as a new therapeutic biomarker for LUAD.

METHODS

We investigated the expression patterns of DRGs in both LUAD and noncancerous tissues. To assess the prognostic value of the DRGs, we developed risk models through univariate Cox analysis and lasso regression. The expression and function of ACTN4 was evaluated by qRT-PCR, immunohistochemistry and in vitro experiments. The TIMER examined the association between ACTN4 expression and immune infiltration in LUAD.

RESULTS

Ten differentially expressed DRGs were identified. And ACTN4 was identified as potential risk factors through univariate Cox regression analysis (P< 0.05). ACTN4 expression and riskscore were used to construct a risk model to predict overall survival in LUAD, and high-risk demonstrated a significantly higher mortality rate compared to the low-risk cohort. qRT-PCR and immunohistochemistry assays indicated ACTN4 was upregulated in LUAD, and the upregulation was associated with clinicopathologic features. In vitro experiments showed the knockdown of ACTN4 expression inhibited the proliferation in LUAD cells. The TIMER analysis demonstrated a correlation between the expression of ACTN4 and the infiltration of diverse immune cells. Elevated ACTN4 expression was associated with a reduction in memory B cell count. Additionally, the ACTN4 expression was associated with m6A modification genes.

CONCLUSIONS

Our study introduced a prognostic model based on DRGs, which could forecast the prognosis of patients with LUAD. The biomarker ACTN4 exhibits promise for the diagnosis and management of LUAD, given its correlation with tumor immune infiltration and m6A modification.

Transforming Diagnosis and Therapeutics Using Cancer Genomics

In past quarter of the century, much has been understood about the genetic variation and abnormal genes that activate cancer in humans. All the cancers somehow possess alterations in the DNA sequence of cancer cell's genome. In present, we are heading toward the era where it is possible to obtain complete genome of the cancer cells for their better diagnosis, categorization and to explore treatment options.

Alpha-actnin-4 (ACTN4) selectively affects the DNA double-strand breaks repair in non-small lung carcinoma cells

BACKGROUND

ACTN4 is an actin-binding protein involved in many cellular processes, including cancer development. High ACTN4 expression is often associated with a poor prognosis. However, it has been identified as a positive marker for platinum-based adjuvant chemotherapy for non-small cell lung cancer (NSCLC). The goal of our study was to investigate the involvement of ACTN4 in the NSCLC cells' response to the genotoxic drugs.

RESULTS

We generated H1299 cells with the ACTN4 gene knock-out (ACTN4 KO), using the CRISPR/Cas9 system. The resistance of the cells to the cisplatin and etoposide was analyzed with the MTT assay. We were also able to estimate the efficiency of DNA repair through the DNA comet assay and gamma-H2AX staining. Possible ACTN4 effects on the non-homologous end joining (NHEJ) and homologous recombination (HR) were investigated using pathway-specific reporter plasmids and through the immunostaining of the key proteins. We found that the H1299 cells with the ACTN4 gene knock-out did not show cisplatin-resistance, but did display a higher resistance to the topoisomerase II inhibitors etoposide and doxorubicin, suggesting that ACTN4 might be somehow involved in the repair of DNA strand breaks. Indeed, the H1299 ACTN4 KO cells repaired etoposide- and doxorubicin-induced DNA breaks more effectively than the control cells. Moreover, the ACTN4 gene knock-out enhanced NHEJ and suppressed HR efficiency. Supporting the data, the depletion of ACTN4 resulted in the faster assembly of the 53BP1 foci with a lower number of the phospho-BRCA1 foci after the etoposide treatment.

CONCLUSIONS

Thus, we are the first to demonstrate that ACTN4 may influence the resistance of cancer cells to the topoisomerase II inhibitors, and affect the efficiency of the DNA double strand breaks repair. We hypothesize that ACTN4 interferes with the assembly of the NHEJ and HR complexes, and hence regulates balance between these DNA repair pathways.

Benefits from Adjuvant Chemotherapy in Patients with Resected Non-Small Cell Lung Cancer: Possibility of Stratification by Gene Amplification of ACTN4 According to Evaluation of Metastatic Ability

Surgical treatment is the best curative treatment option for patients with non-small cell lung cancer (NSCLC), but some patients have recurrence beyond the surgical margin even after receiving curative surgery. Therefore, therapies with anti-cancer agents also play an important role perioperatively. In this paper, we review the current status of adjuvant chemotherapy in NSCLC and describe promising perioperative therapies, including molecularly targeted therapies and immune checkpoint inhibitors. Previously reported biomarkers of adjuvant chemotherapy for NSCLC are discussed along with their limitations. Adjuvant chemotherapy after resective surgery was most effective in patients with metastatic lesions located just outside the surgical margin; in addition, these metastatic lesions were the most sensitive to adjuvant chemotherapy. Thus, the first step in predicting patients who have sensitivity to adjuvant therapies is to perform a qualified evaluation of metastatic ability using markers such as actinin-4 (ACTN4). In this review, we discuss the potential use of biomarkers in patient stratification for effective adjuvant chemotherapy and, in particular, the use of ACTN4 as a possible biomarker for NSCLC.

Binding of alpha-ACTN4 to EGF receptor enables its rapid phosphorylation

Alpha-ACTN4, a member of alpha-actinin family is critical for cell motility through its regulated binding of actin filaments. We previously found that EGF exposure of cells triggers the tyrosyl-phosphorylation of ACTN4 in fibroblasts that dramatically downregulates its binding to actin filaments. However, the exact kinase remained uncertain. In the present study, we report that the phosphorylation of ACTN4 occurs within seconds upon EGF treatments and is accomplished via direct interaction of ACTN4 with the EGF receptor. The major binding domain of ACTN4 for EGF receptor is mapped to the N-terminal 32 amino acids. A second domain minimizes the interaction, as truncation of the C-terminal tail enhances ACTN4 binding to EGF receptor. A mimetic phosphorylated ACTN4, Y4/31E, presents low binding to EGF receptor. Overexpression of EGF receptor in melanoma cell lines, also accomplishes the phosphorylation of ACTN4 in the presence of EGF. These findings suggest that the binding of ACTN4 to EGFR enables its direct and rapid phosphorylation resulting in dissociation from EGFR and decreased binding to actin filaments.

The mechanobiome: a goldmine for cancer therapeutics

Cancer progression is dependent on heightened mechanical adaptation, both for the cells' ability to change shape and to interact with varying mechanical environments. This type of adaptation is dependent on mechanoresponsive proteins that sense and respond to mechanical stress, as well as their regulators. Mechanoresponsive proteins are part of the mechanobiome, which is the larger network that constitutes the cell's mechanical systems that are also highly integrated with many other cellular systems, such as gene expression, metabolism, and signaling. Despite the altered expression patterns of key mechanobiome proteins across many different cancer types, pharmaceutical targeting of these proteins has been overlooked. Here, we review the biochemistry of key mechanoresponsive proteins, specifically nonmuscle myosin II, α-actinins, and filamins, as well as the partnering proteins 14-3-3 and CLP36. We also examined a wide range of data sets to assess how gene and protein expression levels of these proteins are altered across many different cancer types. Finally, we determined the potential of targeting these proteins to mitigate invasion or metastasis and suggest that the mechanobiome is a goldmine of opportunity for anticancer drug discovery and development.

Integrated analysis of lncRNAs and mRNAs reveals key trans-target genes associated with ETEC-F4ac adhesion phenotype in porcine small intestine epithelial cells

BACKGROUND

Long non-coding RNAs (lncRNAs) play crucial roles in gene regulation at the transcriptional and post-transcriptional levels. LncRNAs are belonging to a large class of transcripts with ≥200 nt in length which do not code for proteins, have been widely investigated in various physiological and pathological contexts by high-throughput sequencing techniques and bioinformatics analysis. However, little is known about the regulatory mechanisms by which lncRNAs regulate genes that are associated with Enterotoxigenic Escherichia coli F4 fimbriae (ETEC-F4ac) adhesion phenotype in small intestine epithelial cells of Large White piglets. To address this, we used RNA sequencing to profile lncRNAs and mRNAs of small intestine epithelial cells in Large White piglets differing in their ETEC-F4 adhesion phenotypes and ITGB5 genotypes. Eight male piglets were used in this study and were divided into two groups on the basis of their adhesion phenotype and ITGB5 genotypes, a candidate gene for F4ac receptor. Non-adhesive group (n = 4) with CC genotype and adhesive group (n = 4) with TT genotype.

RESULTS

In total, 78 differentially expressed lncRNAs (DE-lncRNA) and 223 differentially expressed mRNAs (log2 |FC| > 1, P < 0.05) were identified in the comparison of non-adhesive vs. adhesive small intestine epithelial cells. Furthermore, cis- and trans-regulatory target genes of DE-lncRNAs were identified, then interaction networks of lncRNAs and their cis- and trans-target differentially expressed genes (DEGs) were constructed separately. A total of 194 cis-targets were involved in the lncRNAs-cis genes interaction network and 61 trans-targets, were involved in lncRNA-trans gene interaction network that we constructed. We determined that cis-target genes were involved in alcoholism, systemic lupus erythematosus, viral carcinogenesis and malaria. Whereas trans-target DEGs were engaged in three important pathways related to the ETEC-F4 adhesion phenotype namely cGMP-PKG signaling pathway, focal adhesion, and adherens junction. The trans-target DEGs which directly involved in these pathways are KCNMB1 in cGMP-PKG signaling pathway, GRB2 in focal adhesion pathway and ACTN4 in focal adhesion and adherens junction pathways.

CONCLUSION

The findings of the current study provides an insight into biological functions and epigenetic regulatory mechanism of lncRNAs on porcine small intestine epithelial cells adhesion to ETEC-F4-ac and piglets' diarrhea susceptibility/resistance.

Cytoskeletal Remodeling in Cancer

Simple Summary

Cell migration is an essential process from embryogenesis to cell death. This is tightly regulated by numerous proteins that help in proper functioning of the cell. In diseases like cancer, this process is deregulated and helps in the dissemination of tumor cells from the primary site to secondary sites initiating the process of metastasis. For metastasis to be efficient, cytoskeletal components like actin, myosin, and intermediate filaments and their associated proteins should co-ordinate in an orderly fashion leading to the formation of many cellular protrusions-like lamellipodia and filopodia and invadopodia. Knowledge of this process is the key to control metastasis of cancer cells that leads to death in 90% of the patients. The focus of this review is giving an overall understanding of these process, concentrating on the changes in protein association and regulation and how the tumor cells use it to their advantage. Since the expression of cytoskeletal proteins can be directly related to the degree of malignancy, knowledge about these proteins will provide powerful tools to improve both cancer prognosis and treatment.

Abstract

Successful metastasis depends on cell invasion, migration, host immune escape, extravasation, and angiogenesis. The process of cell invasion and migration relies on the dynamic changes taking place in the cytoskeletal components; actin, tubulin and intermediate filaments. This is possible due to the plasticity of the cytoskeleton and coordinated action of all the three, is crucial for the process of metastasis from the primary site. Changes in cellular architecture by internal clues will affect the cell functions leading to the formation of different protrusions like lamellipodia, filopodia, and invadopodia that help in cell migration eventually leading to metastasis, which is life threatening than the formation of neoplasms. Understanding the signaling mechanisms involved, will give a better insight of the changes during metastasis, which will eventually help targeting proteins for treatment resulting in reduced mortality and longer survival.

Actinin-4 Expression Predicts Poor Disease-free Survival and Correlates with Delayed Lymph Node Metastasis in Patients with Completely Resected Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma is generally characterized by poor prognosis, and biomarkers are needed for development and selection of therapy. The purpose of this study was to assess expression of actinin-4, which has been implicated in cancer invasion and metastasis, to determine its viability as a prognostic indicator in oral squamous cell carcinoma. Clinical factors and tumor samples immunohistochemically stained for actinin-4 were retrospectively investigated in 55 patients who underwent curative surgery for oral squamous cell carcinoma. Overall survival and disease-free survival were estimated by Kaplan-Meier analysis. Significant differences were detected using the Pearson's chi-square and Fisher's exact tests. Univariate and multivariate analyses were performed with the Cox regression model. No association was found between expression of actinin-4 and clinical factors, including age or sex, or histopathological factors, including vascular invasion, lymphatic invasion, stage, mode of invasion, or histological atypicality. Expression of actinin-4 showed a positive correlation with delayed cervical lymph node metastasis. Disease-free survival was significantly lower in patients who were positive for expression of actinin-4 (p=0.010); overall survival showed no difference between patients with or without expression of actinin-4, however. The results revealed that actinin-4 was an independent prognostic factor for disease-free survival. Expression of actinin-4 showed a 73% sensitivity and 68% specificity for prediction of delayed cervical lymph node metastasis. In conclusion, actinin-4 may potentially be a useful biomarker for prediction of delayed cervical lymph node metastasis.

Role of ACTN4 in Tumorigenesis, Metastasis, and EMT

The actin-binding protein ACTN4 belongs to a family of actin-binding proteins and is a non-muscle alpha-actinin that has long been associated with cancer development. Numerous clinical studies showed that changes in ACTN4 gene expression are correlated with aggressiveness, invasion, and metastasis in certain tumors. Amplification of the 19q chromosomal region where the gene is located has also been reported. Experimental manipulations with ACTN4 expression further confirmed its involvement in cell proliferation, motility, and epithelial-mesenchymal transition (EMT). However, both clinical and experimental data suggest that the effects of ACTN4 up- or down-regulation may vary a lot between different types of tumors. Functional studies demonstrated its engagement in a number of cytoplasmic and nuclear processes, ranging from cytoskeleton reorganization to regulation of different signaling pathways. Such a variety of functions may be the reason behind cell type and cell line specific responses. Herein, we will review research progress and controversies regarding the prognostic and functional significance of ACTN4 for tumorigenesis.

Targeting Mechanoresponsive Proteins in Pancreatic Cancer: 4-Hydroxyacetophenone Blocks Dissemination and Invasion by Activating MYH14

Metastasis is complex, involving multiple genetic, epigenetic, biochemical, and physical changes in the cancer cell and its microenvironment. Cells with metastatic potential are often characterized by altered cellular contractility and deformability, lending them the flexibility to disseminate and navigate through different microenvironments. We demonstrate that mechanoresponsiveness is a hallmark of pancreatic cancer cells. Key mechanoresponsive proteins, those that accumulate in response to mechanical stress, specifically nonmuscle myosin IIA (MYH9) and IIC (MYH14), α-actinin 4, and filamin B, were highly expressed in pancreatic cancer as compared with healthy ductal epithelia. Their less responsive sister paralogs-myosin IIB (MYH10), α-actinin 1, and filamin A-had lower expression differential or disappeared with cancer progression. We demonstrate that proteins whose cellular contributions are often overlooked because of their low abundance can have profound impact on cell architecture, behavior, and mechanics. Here, the low abundant protein MYH14 promoted metastatic behavior and could be exploited with 4-hydroxyacetophenone (4-HAP), which increased MYH14 assembly, stiffening cells. As a result, 4-HAP decreased dissemination, induced cortical actin belts in spheroids, and slowed retrograde actin flow. 4-HAP also reduced liver metastases in human pancreatic cancer-bearing nude mice. Thus, increasing MYH14 assembly overwhelms the ability of cells to polarize and invade, suggesting targeting the mechanoresponsive proteins of the actin cytoskeleton as a new strategy to improve the survival of patients with pancreatic cancer. SIGNIFICANCE: This study demonstrates that mechanoresponsive proteins become upregulated with pancreatic cancer progression and that this system of proteins can be pharmacologically targeted to inhibit the metastatic potential of pancreatic cancer cells.

Actinin-4 as a Diagnostic Biomarker in Serum of Breast Cancer Patients

Background

α-actinin-4 (Actinin-4 or ACTN4), originally identified as an actin-binding protein associated with the biological function of cancer cells, appears to be highly expressed in numerous human epithelial carcinomas, including breast cancer (BC). In the present study we assessed the role of serum ACTN4 as a biomarker for BC diagnosis, as well as the association between ACTN4 levels and clinicopathological features.

Material/Methods

ACTN4 expression level was measured with quantitative real-time PCR (qRT-PCR) analysis in serum specimens of 128 BC patients and 96 healthy volunteers. χ² testing was conducted to explore the association of ACTN4 levels with clinicopathologic factors. Moreover, the diagnostic value of ACTN4 was analyzed using receiver operating characteristic (ROC) curves.

Results

Serum ACTN4 level was obviously upregulated in patients with BC compared with healthy controls (P<0.05). High ACTN4 expression was significantly associated with clinical stage (P=0.000), tumor grade (P=0.004), and lymph node status (P=0.024). However, no association was found between ACTN4 expression and age, tumor size, ER status, PR status, or HER-2 status (all P>0.05). The ROC analysis showed that the area under the curve (AUC) of ACTN4 was 0.887 (95%CI: 0.843–0.931), with sensitivity of 80.5% and specificity of 84.4%, and the cutoff value was 1.050.

Conclusions

ACTN4 in serum can serve as a clinical predictor in the diagnosis or prediction of clinical outcomes of patients with BC.

Clinical multi-omics strategies for the effective cancer management

Cancer is a global health issue as a multi-factorial complex disease, and early detection and novel therapeutic strategies are required for more effective cancer management. With the development of systemic analytical -omics strategies, the therapeutic approach and study of the molecular mechanisms of carcinogenesis and cancer progression have moved from hypothesis-driven targeted investigations to data-driven untargeted investigations focusing on the integrated diagnosis, treatment, and prevention of cancer in individual patients. Predictive, preventive, and personalized medicine (PPPM) is a promising new approach to reduce the burden of cancer and facilitate more accurate prognosis, diagnosis, as well as effective treatment. Here we review the fundamentals of, and new developments in, -omics technologies, together with the key role of a variety of practical -omics strategies in PPPM for cancer treatment and diagnosis.

BIOLOGICAL SIGNIFICANCE

In this review, a comprehensive and critical overview of the systematic strategy for predictive, preventive, and personalized medicine (PPPM) for cancer disease was described in a view of cancer prognostic prediction, diagnostics, and prevention as well as cancer therapy and drug responses. We have discussed multi-dimensional data obtained from various resources and integration of multisciplinary -omics strategies with computational method which could contribute the more effective PPPM for cancer. This review has provided the novel insights of the current applications of each and combined -omics technologies, which showed their powerful potential for the establishment of PPPM for cancer.