4.1N is involved in a flotillin-1/β-catenin/Wnt pathway and suppresses cell proliferation and migration in non-small cell lung cancer cell lines

Identification of a unique stress response state of T cells-related gene signature in patients with gastric cancer

Gastric cancer (GC), the third most lethal cancer worldwide, is often diagnosed at an advanced stage, leaving limited therapeutic options. Given the diverse outcomes among GC patients with similar AJCC/UICC-TNM characteristics, there is a pressing need for more reliable prognostic tools. Recent advances in targeted therapy and immunotherapy have underscored this necessity. In this context, our study focused on a novel stress response state of T cells, termed TSTR, identified across multiple cancers, which is associated with resistance to immunotherapy. We aimed to develop a predictive gene signature for the TSTR phenotype within the tumor microenvironment (TME) of GC patients. By categorizing GC patients into high and low TSTR groups based on the infiltration states of TME TSTR cells, we observed significant differences in clinical prognosis and characteristics between the groups. Through a multi-step bioinformatics approach, we established an eight-gene signature based on genes differentially expressed between these groups. We conducted functional validations for the signature gene PDGFRL in GC cells. This gene signature effectively stratifies GC patients into high and low-risk categories, demonstrating robustness in predicting clinical outcomes. Furthermore, these risk groups exhibited distinct immune profiles, somatic mutations, and drug susceptibilities, highlighting the potential of our gene signature to enhance personalized treatment strategies in clinical practice.

Subtype classification based on t cell proliferation-related regulator genes and risk model for predicting outcomes of lung adenocarcinoma

Background

Lung adenocarcinoma (LUAD), the major lung cancer histotype, represents 40% lung cancers. Currently, outcomes are remarkably different in LUAD patients with similar AJCC/UICC-TNM features. T cell proliferation-related regulator genes (TPRGs) relate to the proliferation, activity and function of T cells and tumor progression. The values of TPRGs in classifying LUAD patients and predicting outcomes remain unknown.

Methods

Gene expression profile and corresponding clinical data were downloaded from TCGA and the GEO databases. We systematically analyzed the expression profile characteristics of 35 TPRGs in LUAD patients and investigated the differences in overall survival (OS), biology pathway, immunity and somatic mutation between different TPRGs-related subtypes. Subsequently, we constructed a TPRGs-related risk model in TCGA cohort to quantify risk scores using LASSO cox regression analysis and then validated this risk model in two GEO cohorts. LUAD patients were divided into high- and low-risk subtypes according to the median risk score. We systematically compared the biology pathway, immunity, somatic mutation and drug susceptibility between the two risk subtypes. Finally, we validate biological functions of two TPRGs-encoded proteins (DCLRE1B and HOMER1) in LUAD cells A549.

Results

We identified different TPRGs-related subtypes (including cluster 1/cluster A and its counterpart cluster 2/cluster B). Compared to the cluster 1/cluster A subtype, cluster 2/cluster B subtype tended to have a prominent survival advantage with an immunosuppressive microenvironment and a higher somatic mutation frequency. Then, we constructed a TPRGs-related 6-gene risk model. The high-risk subtype characterized by higher somatic mutation frequency and lower immunotherapy response had a worse prognosis. This risk model was an independent prognostic factor and showed to be reliable and accurate for LUAD classification. Furthermore, subtypes with different risk scores were significantly associated with drug sensitivity. DCLRE1B and HOMER1 suppressed cell proliferation, migration and invasion in LUAD cells A549, which was in line with their prognostic values.

Conclusion

We construed a novel stratification model of LUAD based on TPRGs, which can accurately and reliably predict the prognosis and might be used as a predictive tool for LUAD patients.

Tumor Suppressor 4.1N/EPB41L1 is Epigenetic Silenced by Promoter Methylation and MiR-454-3p in NSCLC

Non–small-cell lung cancer (NSCLC) is divided into three major histological types, namely, lung adenocarcinoma (LUAD), lung squamous cell carcinoma (LUSC), and large-cell lung carcinoma (LCLC). We previously identified that 4.1N/EPB41L1 acts as a tumor suppressor and is reduced in NSCLC patients. In the current study, we explored the underlying epigenetic mechanisms of 4.1N/EPB41L1 reduction in NSCLC. The 4.1N/EPB41L1 gene promoter region was highly methylated in LUAD and LUSC patients. LUAD patients with higher methylation level in the 4.1N/EPB41L1 gene promoter (TSS1500, cg13399773 or TSS200, cg20993403) had a shorter overall survival time (Log-rank p = 0.02 HR = 1.509 or Log-rank p = 0.016 HR = 1.509), whereas LUSC patients with higher methylation level in the 4.1N/EPB41L1 gene promoter (TSS1500 cg13399773, TSS1500 cg07030373 or TSS200 cg20993403) had a longer overall survival time (Log-rank p = 0.045 HR = 0.5709, Log-rank p = 0.018 HR = 0.68 or Log-rank p = 0.014 HR = 0.639, respectively). High methylation of the 4.1N/EPB41L1 gene promoter appeared to be a relatively early event in LUAD and LUSC. DNA methyltransferase inhibitor 5-Aza-2′-deoxycytidine restored the 4.1N/EPB41L1 expression at both the mRNA and protein levels. MiR-454-3p was abnormally highly expressed in NSCLC and directly targeted 4.1N/EPB41L1 mRNA. MiR-454-3p expression was significantly correlated with 4.1N/EPB41L1 expression in NSCLC patients (r = −0.63, p < 0.0001). Therefore, we concluded that promoter hypermethylation of the 4.1N/EPB41L1 gene and abnormally high expressed miR-454-3p work at different regulation levels but in concert to restrict 4.1N/EPB41L1 expression in NSCLC. Taken together, this work contributes to elucidate the underlying epigenetic disruptions of 4.1N/EPB41L1 deficiency in NSCLC.

DEK modulates both expression and alternative splicing of cancer‑related genes

DEK is known to be a potential proto‑oncogene and is highly expressed in gastric cancer (GC); thus, DEK is considered to contribute to the malignant progression of GC. DEK is an RNA‑binding protein involved in transcription, DNA repair, and selection of splicing sites during mRNA processing; however, its precise function remains elusive due to the lack of clarification of the overall profiles of gene transcription and post‑transcriptional splicing that are regulated by DEK. We performed our original whole‑genomic RNA‑Seq data to analyze the global transcription and alternative splicing profiles in a human GC cell line by comparing DEK siRNA‑treated and control conditions, dissecting both differential gene expression and potential alternative splicing events regulated by DEK. The siRNA‑mediated knockdown of DEK in a GC cell line led to significant changes in gene expression of multiple cancer‑related genes including both oncogenes and tumor suppressors. Moreover, it was revealed that DEK regulated a number of alternative splicing in genes which were significantly enriched in various cancer‑related pathways including apoptosis and cell cycle processes. This study clarified for the first time that DEK has a regulatory effect on the alternative splicing, as well as on the expression, of numerous cancer‑related genes, which is consistent with the role of DEK as a possible oncogene. Our results further expand the importance and feasibility of DEK as a clinical therapeutic target for human malignancies including GC.

Flotillin-1 promotes progression and dampens chemosensitivity to cisplatin in gastric cancer via ERK and AKT signaling pathways

BACKGROUND

Several past studies have reported the overexpression of Flotillin-1 in a variety of cancer types. Cisplatin is a chemotherapeutic drug commonly used for cancer treatment. The present study investigated the role of Flotillin-1 in the progression of GC and assessed whether it assists in the chemical sensitization of GC cells toward cisplatin.

METHOD

The expression of Flotillin-1 was detected both in human gastric mucosal cells and GC cells. Next, siRNA and shRNA were used to construct a stable cell line expressing low levels of Flotillin-1. Furthermore, the Cell Counting Kit 8 (CCK-8), flow cytometry, and transwell assays were employed to detect the impact of Flotillin-1 on GC cells. In addition, a nude mouse model of human GC was used to verify the knockdown of Flotillin-1 to increase the sensitivity of GC cells to cisplatin.

RESULTS

Flotillin-1 was overexpressed in GC cells when compared to that in human gastric mucosal cells. The results for in vitro and vivo assays revealed that the knockdown of Flotillin-1 could significantly inhibit the proliferation of GC cells and increased the sensitivity of GC cells to cisplatin via the regulation of the protein kinase B (AKT) and extracellular signal-regulated kinase (ERK) signaling pathway.

CONCLUSION

Flotillin-1 might be used as a molecular marker for GC diagnosis and could be explored as a potential new target for the treatment of GC.

4.1N-Mediated Interactions and Functions in Nerve System and Cancer

Scaffolding protein 4.1N is a neuron-enriched 4.1 homologue. 4.1N contains three conserved domains, including the N-terminal 4.1-ezrin-radixin-moesin (FERM) domain, internal spectrin–actin–binding (SAB) domain, and C-terminal domain (CTD). Interspersed between the three domains are nonconserved domains, including U1, U2, and U3. The role of 4.1N was first reported in the nerve system. Then, extensive studies reported the role of 4.1N in cancers and other diseases. 4.1N performs numerous vital functions in signaling transduction by interacting, locating, supporting, and coordinating different partners and is involved in the molecular pathogenesis of various diseases. In this review, recent studies on the interactions between 4.1N and its contactors (including the α7AChr, IP3R1, GluR1/4, GluK1/2/3, mGluR8, KCC2, D2/3Rs, CASK, NuMA, PIKE, IP6K2, CAM 1/3, βII spectrin, flotillin-1, pp1, and 14-3-3) and the 4.1N-related biological functions in the nerve system and cancers are specifically and comprehensively discussed. This review provides critical detailed mechanistic insights into the role of 4.1N in disease relationships.

PRR11 unveiled as a top candidate biomarker within the RBM3-regulated transcriptome in pancreatic cancer

The outlook for patients with pancreatic cancer remains dismal. Treatment options are limited and chemotherapy remains standard of care, leading to only modest survival benefits. Hence, there is a great need to further explore the mechanistic basis for the intrinsic therapeutic resistance of this disease, and to identify novel predictive biomarkers. RNA‐binding motif protein 3 (RBM3) has emerged as a promising biomarker of disease severity and chemotherapy response in several types of cancer, including pancreatic cancer. The aim of this study was to unearth RBM3‐regulated genes and proteins in pancreatic cancer cells in vitro, and to examine their expression and prognostic significance in human tumours. Next‐generation RNA sequencing was applied to compare transcriptomes of MIAPaCa‐2 cells with and without RBM3 knockdown. The prognostic value of differentially expressed genes (DEGs) was examined in The Cancer Genome Atlas (TCGA). Top deregulated genes were selected for further studies in vitro and for immunohistochemical analysis of corresponding protein expression in tumours from a clinically well‐annotated consecutive cohort of 46 patients with resected pancreatic cancer. In total, 19 DEGs (p < 0.01) were revealed, among which some with functions in cell cycle and cell division stood out; PDS5A (PDS cohesin associated factor A) as the top downregulated gene, CCND3 (cyclin D3) as the top upregulated gene, and PRR11 (proline rich 11) as being highly prognostic in TCGA. Silencing of RBM3 in MiaPaCa‐2 cells led to congruent alterations of PDS5A, cyclin D3, and PRR11 levels. High protein expression of PRR11 was associated with adverse clinicopathological features and shorter overall survival. Neither PDS5A nor cyclin D3 protein expression was prognostic. This study unveils several RBM3‐regulated genes with potential clinical relevance in pancreatic cancer, among which PRR11 shows the most consistent association with disease severity, at both transcriptome and protein levels.

Loss of 4.1N in epithelial ovarian cancer results in EMT and matrix-detached cell death resistance

Epithelial ovarian cancer (EOC) is one of the leading causes of death from gynecologic cancers and peritoneal dissemination is the major cause of death in patients with EOC. Although the loss of 4.1N is associated with increased risk of malignancy, its association with EOC remains unclear. To explore the underlying mechanism of the loss of 4.1N in constitutive activation of epithelial-mesenchymal transition (EMT) and matrix-detached cell death resistance, we investigated samples from 268 formalin-fixed EOC tissues and performed various in vitro and in vivo assays. We report that the loss of 4.1N correlated with progress in clinical stage, as well as poor survival in EOC patients. The loss of 4.1N induces EMT in adherent EOC cells and its expression inhibits anoikis resistance and EMT by directly binding and accelerating the degradation of 14-3-3 in suspension EOC cells. Furthermore, the loss of 4.1N could increase the rate of entosis, which aggravates cell death resistance in suspension EOC cells. Moreover, xenograft tumors in nude mice also show that the loss of 4.1N can aggravate peritoneal dissemination of EOC cells. Single-agent and combination therapy with a ROCK inhibitor and a 14-3-3 antagonist can reduce tumor spread to varying degrees. Our results not only define the vital role of 4.1N loss in inducing EMT, anoikis resistance, and entosis-induced cell death resistance in EOC, but also suggest that individual or combined application of 4.1N, 14-3-3 antagonists, and entosis inhibitors may be a promising therapeutic approach for the treatment of EOC.

Belinostat suppresses cell proliferation by inactivating Wnt/β-catenin pathway and promotes apoptosis through regulating PKC pathway in breast cancer

Belinostat is a histone deacetylase inhibitor drug capable of regulating cell growth in diverse cancers. Nonetheless, little information clarified the role of Belinostat in breast cancer. Hence, the functions of Belinostat in breast cancer cells survival was disclosed in this study. Belinostat at 50 and 100 μM were applied to manage MCF-7 cells, cell viability, Ki67 positive cells, cell cycle and apoptosis were monitored via MTT, immunohistochemistry and flow cytometry. Furthermore, the apoptosis-related factors, Wnt/β-catenin pathway and PKC pathway were tested through western blot and qRT-PCR. Lastly, in vivo effect of Belinostat was determined by a murine model. The results showed that Belinostat dampened cell viability, decreased the proportion of Ki67 positive cells and arrested cells at G0/G1 phase. The decreases of Wnt/β-catenin, CCND2 and Myc were observed in MCF-7 cells after Belinostat stimulation. Additionally, Belinostat induced cell apoptosis, meanwhile dampened Bcl-2 and raised Bax and Cleaved caspase 3 in a dose and time-dependent manner. Additionally, Belinostat activated PKC pathway by upgrading PKCδ and P53 expressions. Furthermore, Belinostat restrained tumour weight and volume in vivo. In summary, this study depicted that Belinostat prohibited proliferation and evoked apoptosis via mediating Wnt/β-catenin and PKC pathways in MCF-7 cells.

Protein 4.1N is required for the formation of the lateral membrane domain in human bronchial epithelial cells

The membrane skeleton forms a scaffold on the cytoplasmic side of the plasma membrane. The erythrocyte membrane represents an archetype of such structural organization. It has been documented that a similar membrane skeleton also exits in the Golgi complex. It has been previously shown that βII spectrin and ankyrin G are localized at the lateral membrane of human bronchial epithelial cells. Here we show that protein 4.1N is also located at the lateral membrane where it associates E-cadherin, β-catenin and βII spectrin. Importantly, depletion of 4.1N by RNAi in human bronchial epithelial cells resulted in decreased height of lateral membrane, which was reversed following re-expression of mouse 4.1N. Furthermore, although the initial phase of lateral membrane biogenesis proceeded normally in 4.1N-depleted cells, the final height of the lateral membrane of 4.1N-depleted cells was shorter compared to that of control cells. Our findings together with previous findings imply that 4.1N, βII spectrin and ankyrin G are structural components of the lateral membrane skeleton and that this skeleton plays an essential role in the assembly of a fully functional lateral membrane.

HG30, a tetrahydroanthraquinone compound isolated from the roots of Prismatomeris connate, induces apoptosis in human non-small cell lung cancer cells

HG30, a tetrahydroanthraquinone compound isolated from the roots of Prismatomeris connate, was previously shown to inhibit the proliferation of A549 cells. The aim of this study was to evaluate the antitumor activity of HG30 in two non-small cell lung cancer cell lines, A549 and H1299, and to explore potential underlying mechanisms. In cell viability and colony formation assays, HG30 treatment suppressed the proliferation and number of colonies formed by A549 and H1299 cells. Western blot analysis further demonstrated that induction of apoptosis by HG30 in A549 and H1299 cells involves both caspase-dependent apoptosis pathways, including mitochondria- and death receptor-mediated pathways, and an apoptosis-inducing factor (AIF) -associated caspase-independent apoptosis pathway. Specifically, HG30 treatment affected Bcl-2 family proteins and inhibitor of apoptosis protein (IAP) family proteins by down-regulating of Mcl-1, survivin and XIAP and up-regulation of Bid, and Bim.