Tumor Suppressor Role Research Articles

HDAC1 and FOXK1 mediate EGFR-TKI resistance of non-small cell lung cancer through miR-33a silencing

BackgroundThe development of acquired EGFR-TKI treatment resistance is still a major clinical challenge in the treatment of non-small cell lung cancer (NSCLC). This study aimed to investigate the role of HDAC1/FOXK1/miR-33a signaling in EGFR-TKI resistance.MethodsThe expression levels of miR‐33a, HDAC1, and FOXK1 were examined using quantitative polymerase chain reaction (PCR) and bioinformatics analysis. Cell proliferation, migration, and apoptosis were explored by cell number assay, Transwell, and flow cytometry assays, respectively. After overexpression or knockdown of HDAC1, miR-33a expression in the cells, cell functions were tested. Immunoprecipitation and correlation analyses were used to evaluate the interaction between HDAC1 and FOXK1 protein. The tumor-suppressive role of miR-33a was investigated by animal experiments.ResultsThe suppression of miR-33a increased TKI resistance by affecting cell proliferation, migration, and apoptosis in gefitinib-resistant cells. HDAC1 is the key upstream molecule that inhibits miR-33 expression. HDAC1 upregulation increased gefitinib resistance by its binding to FOXK1 in cells to silence miR-33a expression. MiR-33a overexpression exerts tumor-suppressive effects by negatively regulating ABCB7 and p70S6K1 expression. Moreover, overexpression of miR-33a inhibited tumor growth in a xenograft nude mouse model.ConclusionsHDAC1/FOXK1 upregulation and miR-33a silencing are new mechanisms of EGFR-TKI resistance in NSCLC.

ITCH inhibits alkaliptosis in human pancreatic cancer cells through YAP1-dependent SLC16A1 activation

Alkaliptosis is a type of pH-dependent cell death and plays an emerging role in tumor suppression. However, the key modulation mechanism of alkaliptosis remains largely unknown. In particular, the nucleus, as the centre of genetic and metabolic regulation, is crucial for the regulation of cellular life. It is not known whether nuclear proteins are involved in the regulation of alkaliptosis. Here, we isolated nuclear proteins to perform a proteomics that identified itchy E3 ubiquitin protein ligase (ITCH) as a natural inhibitor of alkaliptosis in human pancreatic ductal adenocarcinoma (PDAC) cells. The downregulation of ITCH protein is associated with the induction of alkaliptosis in three human PDAC cell lines (SW1990, MiaPaCa2, and PANC1). Functionally, increasing ITCH expression reduces JTC801-induced growth inhibition and cell death. In contrast, knocking down ITCH using specific shRNA increases JTC801-induced cell growth inhibition in the short or long term, resulting in increased cell death. Mechanistically, JTC801-induced ITCH inhibition blocks large tumor suppressor kinase 1 (LATS1) ubiquitination, which in turn suppresses Yes1 associated transcriptional regulator (YAP1)-dependent the transcriptional activation of solute carrier family 16 member 1 (SLC16A1), a proton-linked monocarboxylate transporter that inhibits JTC801-induced alkaliptosis. Additionally, decreased expression of ITCH is associated with longer survival times in patients with PDAC. Collectively, our results establish an ITCH-dependent pathway that regulates alkaliptotic sensitivity in PDAC cells and deepen the understanding of alkaliptosis in targeted therapy.

Sirtuin 5 (SIRT5) Suppresses Tumor Growth by Regulating Mitochondrial Metabolism and Synaptic Remodeling in Gliomas.

Sirtuin 5 (SIRT5) is increasingly recognized as a key regulator of cellular metabolism, which is commonly dysregulated in cancer cells, resulting in enhanced proliferation and tumor progression. To investigate the clinicopathologic implications of SIRT5 dysregulation in glioblastoma, we performed comprehensive analyses of transcriptomic data and functional verifications using in vitro and in vivo glioblastoma models. We found that higher SIRT5 expression levels were associated with a favorable prognosis in glioma patients. Knockdown of SIRT5 significantly enhanced glioblastoma cell growth. Our data suggest its potential role in regulating mitochondrial metabolism in gliomas. Furthermore, SIRT5 is also significantly correlated with synaptic remodeling pathways. Our findings indicate a tumor-suppressive role for SIRT5 that extends beyond regulating cancer metabolism, by which it may function through modulating neuroplasticity. Understanding these cellular interactions provides nuanced insights into the multifaceted role of SIRT5 and the broader therapeutic implications of this for the development of novel treatment strategies.

The lipid-metabolism enzyme ECI2 reduces neutrophil extracellular traps formation for colorectal cancer suppression

Abnormalities in ether lipid metabolism as well as the formation of neutrophil extracellular traps have recently been recognized as detrimental factors affecting tumorigenesis and progression. However, the role of abnormal ether lipid metabolism in colorectal cancer (CRC) evolution has not been reported. Here we show that the lipid metabolism-related gene enoyl-CoA δ-isomerase 2 (ECI2) plays a tumor-suppressor role in CRC and is negatively associated with poor prognosis in CRC patients. We mechanistically demonstrate that ECI2 reduces ether lipid-mediated Interleukin 8 (IL-8) expression leading to decreased neutrophil recruitment and neutrophil extracellular traps formation for colorectal cancer suppression. In particular, ECI2 inhibits ether lipid production in CRC cells by inhibiting the peroxisomal localization of alkylglycerone phosphate synthase (AGPS), the rate-limiting enzyme for ether lipid synthesis. These findings not only deepen our understanding of the role of metabolic reprogramming and neutrophil interactions in the progression of CRC, but also provide ideas for identifying potential diagnostic markers and therapeutic targets for CRC.

Hippo pathway effectors YAP, TAZ and TEAD are associated with EMT master regulators ZEB, Snail and with aggressive phenotype in phyllodes breast tumors

BackgroundPhyllodes tumors (PTs) of the breast are uncommon fibroepithelial neoplasms that tend to recur locally and may have metastatic potential. Their pathogenesis is poorly understood. Hippo signaling pathway plays an essential role in organ size control, tumor suppression, tissue regeneration and stem cell self-renewal. Hippo signaling dysfunction has been implicated in cancer. Recent evidence suggests that there is cross-talk between the Hippo signaling key proteins YAP/TAZ and the epithelial-mesenchymal transition (EMT) master regulators Snail and ZEB. In this study we aimed to investigate the expression of Hippo signaling pathway components and EMT regulators in PTs, in relation to tumor grade. MethodsExpression of Hippo signaling effector proteins YAP, TAZ and their DNA binding partner TEAD was evaluated by immunohistochemistry in paraffin-embedded tissue specimens from 86 human phyllodes breast tumors (45 benign, 21 borderline, 20 malignant), in comparison with tumor grade and with the expression of EMT-related transcription factors ZEB and Snail. ResultsNuclear immunopositivity for YAP, TAZ and TEAD was detected in both stromal and epithelial cells in PTs and was significantly higher in high grade tumors. Interestingly, there was a significant correlation between the expression of YAP, TAZ, TEAD and the expression of ZEB and SNAIL. ConclusionsOur results originally implicate Hippo signaling pathway in PTs pathogenesis and suggest that an interaction between Hippo signaling key components and EMT regulators may promote the malignant features of PTs.

The Overexpressed MicroRNAs miRs-182, 155, 493, 454, and U6 snRNA and Underexpressed let-7c, miR-328, and miR-451a as Potential Biomarkers in Invasive Breast Cancer and Their Clinicopathological Significance.

Breast cancer comprises the leading cause of cancer-related death in women. MicroRNAs (miRNAs) have emerged as important factors with concern to carcinogenesis and have potential for use as biomarkers. This study provides a comprehensive evaluation of the microRNA expression in invasive breast carcinoma of no special type tissues compared with benign tissues via large-scale screening and the candidate-specific validation of 15 miRNAs and U6 snRNA applying qPCR and the examination of clinicopathological data. Of the six downregulated miRNAs, let-7c was identified as the most promising miRNA biomarker and its lower expression was linked with Ki-67 positivity, luminal B versus luminal A samples, multifocality, lymph node metastasis, and inferior PFS. Of the 9 upregulated sncRNAs, the data on U6 snRNA, miR-493 and miR-454 highlighted their potential oncogenic functions. An elevated U6 snRNA expression was associated with the tumor grade, Ki-67 positivity, luminal B versus A samples, lymph node metastasis, and worsened PFS (and OS) outcomes. An elevated miR-454 expression was detected in higher grades, Ki-67 positive and luminal B versus A samples. Higher miR-493 levels were noted for the tumor stage (and grade) and worse patient outcomes (PFS, OS). The data also suggested that miR-451a and miR-328 may have tumor suppressor roles, and miR-182 and miR-200c pro-oncogenic functions, while the remaining sncRNAs did not evince any significant associations. We showed particular microRNAs and U6 snRNA as differentially expressed between tumors and benign tissues and associated with clinicopathological parameters, thus potentially corresponding with important roles in breast carcinogenesis. Their importance should be further investigated and evaluated in follow-up studies to reveal their potential in clinical practice.

Genes Co-Expressed with ESR2 Influence Clinical Outcomes in Cancer Patients: TCGA Data Analysis.

ERβ has been assigned a tumor suppressor role in many cancer types. However, as conflicting findings emerge, ERβ's tissue-specific expression and functional role have remained elusive. There remains a notable gap in compact and comprehensive analyses of ESR2 mRNA expression levels across diverse tumor types coupled with an exploration of its potential gene network. In this study, we aim to address these gaps by presenting a comprehensive analysis of ESR2 transcriptomic data. We distinguished cancer types with significant changes in ESR2 expression levels compared to corresponding healthy tissue and concluded that ESR2 influences patient survival. Gene Set Enrichment Analysis (GSEA) distinguished molecular pathways affected by ESR2, including oxidative phosphorylation and epithelial-mesenchymal transition. Finally, we investigated genes displaying similar expression patterns as ESR2 in tumor tissues, identifying potential co-expressed genes that may exert a synergistic effect on clinical outcomes, with significant results, including the expression of ACIN1, SYNE2, TNFRSF13C, and MDM4. Collectively, our results highlight the significant influence of ESR2 mRNA expression on the transcriptomic landscape and the overall metabolism of cancerous cells across various tumor types.

Decreased sirtuin 4 levels promote cellular proliferation and invasion in papillary thyroid carcinoma.

This study examined the effect of sirtuin 4 (SIRT4), a NAD+-dependent deacetylase, on the proliferation and progression of papillary thyroid carcinoma (PTC). Data from The Cancer Genome Atlas (TCGA) were analyzed to identify SIRT4 expression in thyroid cancer. Subsequently, the correlation between SIRT4 expression and clinical characteristics was examined in 205 PTC tissue samples. In vitro assays using three human thyroid cancer cell lines (B-CPAP, TPC-1, and SNU-790) were conducted to assess the effects of regulated SIRT4 expression on cell growth, apoptosis, invasion, and migration. Furthermore, in vivo experiments were performed in a xenograft mouse model. Gene Expression Omnibus (GEO) and TCGA data indicated that SIRT4 expression is lower in thyroid cancer and SIRT4 downregulation is associated with poor overall survival. In PTC tissues, positive SIRT4 expression was associated with decreased extracapsular extension. In in vitro experiments using three human thyroid cancer cell lines, overexpression of SIRT4 decreased cell survival, clonogenic potential, and invasion and migratory capabilities, as well as inducing apoptosis and increasing reactive oxygen species levels. SIRT4 overexpression upregulated E-cadherin and downregulated N-cadherin, suggesting its potential involvement in the regulation of epithelial-mesenchymal transition. These findings were confirmed in vivo using a xenograft mouse model. This study provides novel insight into the potential contribution of SIRT4 to the regulation of the pathological progression of PTC. The data suggest that SIRT4 plays a tumor-suppressive role in PTC by inhibiting growth, survival, and invasive potential. Future research should investigate the molecular mechanisms underlying these effects of SIRT4.

FOXC1 transcriptionally suppresses ABHD5 to inhibit the progression of renal cell carcinoma through AMPK/mTOR pathway

BackgroundIncreased activity of the transcription factor FOXC1 leads to elevated transcription of target genes, ultimately facilitating the progression of various cancer types. However, there are currently no literature reports on the role of FOXC1 in renal cell carcinoma.MethodsBy using RT-qPCR, immunohistochemistry and Western blotting, FOXC1 mRNA and protein expression was evaluated. Gain of function experiments were utilized to assess the proliferation and metastasis ability of cells. A nude mouse model was created for transplanting tumors and establishing a lung metastasis model to observe cell proliferation and spread in a living organism. Various techniques including biological analysis, CHIP assay, luciferase assay, RT-qRCR and Western blotting experiments were utilized to investigate how FOXC1 contributes to the transcription of ABHD5 on a molecular level. FOXC1 was assessed by Western blot for its impact on AMPK/mTOR signaling pathway.ResultsFOXC1 is down-regulated in RCC, causing unfavorable prognosis of patients with RCC. Further experiments showed that forced FOXC1 expression significantly restrains RCC cell growth and cell metastasis. Mechanically, FOXC1 promotes the transcription of ABHD5 to activate AMPK signal pathway to inhibit mTOR signal pathway. Finally, knockdown of ABHD5 recovered the inhibitory role of FOXC1 overexpression induced cell growth and metastasis suppression.ConclusionIn general, our study demonstrates that FOXC1 exerts its tumor suppressor role by promoting ABHD5 transcription to regulating AMPK/mTOR signal pathway. FOXC1 could serve as both a diagnostic indicator and potential treatment focus for RCC.

Decreased expression of p53 is associated with down expression of zyxin in breast cancer.

Breast cancer (BC) is considered one of the most common malignant tumors leading to death in women, and genetic factors have a crucial role in BC pathogenesis. Zyxin (ZYX) is one of these factors that may be important in p53 level and function. Thus, the present work aimed to investigate the ZYX gene and protein expression in tumor tissue and matched margin tissue and its correlation with the p53 expression. In a present case-control study, 30 tumors and 30 matched margin tissues were obtained from Iran Tumor Bank/Tehran University of Medical Sciences. Real-time polymerase chain reaction and western blot analysis techniques were applied to evaluate the genes and protein expression, respectively. The data showed that expression of the ZYX gene in tumor tissues significantly decreased (p = 0.0274) compared to matched margin tissues. In contrast, the p53 gene expression in tumor tissues had no significant difference with matched margin tissues. Additionally, we observed that ZYX and p53 genes expression in tumor tissues of estrogen receptor-positive patients had significant elevation than estrogen receptor-negative patients (p < 0.001, p < 0.001, respectively). The data of the western blot analysis technique showed that protein expression of ZYX (p = 0.0024) and P53 protein (p = 0.0218) in tumor tissues was significantly reduced compared to matched margin tissues. Additionally, our analysis showed a direct and significant correlation between the expression of ZYX and p53 proteins (r = 0.7797, p = 0.0126) and expression of ZYX and p53 genes (r = 0.3079, p = 0.0187). Based on our observation, ZYX might have a tumor suppressor role and is associated with p53.

PADI3 inhibits epithelial-mesenchymal transition by targeting CKS1-induced signal transduction in colon cancer.

Protein arginine deiminase 3 (PADI3) is involved in various biological processes of human disease. PADI3 has recently received increasing attention due to its role in tumorigenesis. In a previous study, we found that PADI3 plays a tumor suppressor role in colon cancer by inducing cell cycle arrest, but its critical role and mechanism in cancer metastasis remain obscure. In this study, we fully studied the role of PADI3 in colon cancer cell metastasis. The expression levels of related proteins were detected by Western blotting, and Transwell and wound healing assays were used to examine the cell migration ability. Flow cytometry was used to measure and exclude cell apoptosis-affected cell migration. Both overexpression and rescue experiments were employed to elucidate the molecular mechanism of CKS1 in colon cancer cells. The expression levels of PADI3 and CKS1 are negatively related, and PADI3 can promote CKS1 degradation in a ubiquitin-dependent manner. PADI3 can suppress colon cancer cell migration and reduce the wound healing speed by inhibiting CKS1 expression. The molecular mechanism showed that CKS1 can promote EMT by increasing Snail and N-cadherin expression and suppressing E-cadherin expression. PADI3, as a suppressor of CKS1, can block the process of EMT by impairing CKS1-induced Snail upregulation and E-cadherin downregulation; however, the expression of N-cadherin cannot be rescued. CKS1 promotes EMT in colon cancer by regulating Snail/E-cadherin expression, and this effect can be reversed by PADI3 via the promotion of CKS1 degradation in a ubiquitylation-dependent manner.

Epigenetic silencing of BEND4, a novel DNA damage repair gene, is a synthetic lethal marker for ATM inhibitor in pancreatic cancer.

Synthetic lethality is a novel model for cancer therapy. To understand the function and mechanism of BEN domain-containing protein 4 (BEND4) in pancreatic cancer, eight cell lines and a total of 492 cases of pancreatic neoplasia samples were included in this study. Methylation-specific polymerase chain reaction, CRISPR/Cas9, immunoprecipitation assay, comet assay, and xenograft mouse model were used. BEND4 is a new member of the BEN domain family. The expression of BEND4 is regulated by promoter region methylation. It is methylated in 58.1% (176/303) of pancreatic ductal adenocarcinoma (PDAC), 33.3% (14/42) of intraductal papillary mucinous neoplasm, 31.0% (13/42) of pancreatic neuroendocrine tumor, 14.3% (3/21) of mucinous cystic neoplasm, 4.3% (2/47) of solid pseudopapillary neoplasm, and 2.7% (1/37) of serous cystic neoplasm. BEND4 methylation is significantly associated with late-onset PDAC (> 50 years, P < 0.01) and tumor differentiation (P < 0.0001), and methylation of BEND4 is an independent poor prognostic marker (P < 0.01) in PDAC. Furthermore, BEND4 plays tumor-suppressive roles in vitro and in vivo. Mechanistically, BEND4 involves non-homologous end joining signaling by interacting with Ku80 and promotes DNA damage repair. Loss of BEND4 increased the sensitivity of PDAC cells to ATM inhibitor. Collectively, the present study revealed an uncharacterized tumor suppressor BEND4 and indicated that methylation of BEND4 may serve as a potential synthetic lethal marker for ATM inhibitor in PDAC treatment.

A syngeneic spontaneous zebrafish model of tp53-deficient, EGFRvIII, and PI3KCAH1047R-driven glioblastoma reveals inhibitory roles for inflammation during tumor initiation and relapse in vivo.

High-throughput vertebrate animal model systems for the study of patient-specific biology and new therapeutic approaches for aggressive brain tumors are currently lacking, and new approaches are urgently needed. Therefore, to build a patient-relevant in vivo model of human glioblastoma, we expressed common oncogenic variants including activated human EGFRvIII and PI3KCAH1047R under the control of the radial glial-specific promoter her4.1 in syngeneic tp53 loss-of-function mutant zebrafish. Robust tumor formation was observed prior to 45 days of life, and tumors had a gene expression signature similar to human glioblastoma of the mesenchymal subtype, with a strong inflammatory component. Within early stage tumor lesions, and in an in vivo and endogenous tumor microenvironment, we visualized infiltration of phagocytic cells, as well as internalization of tumor cells by mpeg1.1:EGFP+ microglia/macrophages, suggesting negative regulatory pressure by pro-inflammatory cell types on tumor growth at early stages of glioblastoma initiation. Furthermore, CRISPR/Cas9-mediated gene targeting of master inflammatory transcription factors irf7 or irf8 led to increased tumor formation in the primary context, while suppression of phagocyte activity led to enhanced tumor cell engraftment following transplantation into otherwise immune-competent zebrafish hosts. Altogether, we developed a genetically relevant model of aggressive human glioblastoma and harnessed the unique advantages of zebrafish including live imaging, high-throughput genetic and chemical manipulations to highlight important tumor-suppressive roles for the innate immune system on glioblastoma initiation, with important future opportunities for therapeutic discovery and optimizations.

Expression Pattern of PDE4B, PDE4D, and SFRP5 Markers in Colorectal Cancer.

Background and Objectives: Colorectal cancer (CRC) is the most frequently diagnosed malignant disease of the gastrointestinal system, and new diagnostic and prognostic markers are needed to elucidate the complete tumor profile. Materials and Methods: We used CRC tumor tissues (Dukes' A-D) and adjacent noncancerous tissues of 43 patients. Immunohistochemistry was used to examine the expression of phosphodiesterase 4B (PDE4B), phosphodiesterase 4D (PDE4D), and secreted frizzled related protein 5 (SFRP5) markers. We also analyzed the expression levels of PDE4B, PDE4D, and SFRP5 in CRC tissues compared to control tissues using RNA-sequencing data from the UCSC Xena browser. Results: In CRC stages, the distribution of PDE4B-positive cells varied, with differing percentages between epithelium and lamina propria. Statistically significant differences were found in the number of PDE4B-positive epithelial cells between healthy controls and all CRC stages, as well as between different CRC stages. Similarly, significant differences were observed in the number of PDE4B-positive cells in the lamina propria between healthy controls and all CRC stages, as well as between different CRC stages. CRC stage Dukes' C exhibited a significantly higher number of PDE4B-positive cells in the lamina propria compared to CRC stage Dukes' B. Significant differences were noted in the number of PDE4D-positive epithelial cells between healthy controls and CRC stages Dukes' A, B, and D, as well as between CRC stage Dukes' C and stages A, B, and D. CRC stage Dukes' A had significantly more PDE4D-positive cells in the lamina propria compared to stage D. Significant differences were also observed in the number of SFRP5-positive cells in the lamina propria between healthy controls and all CRC stages, as well as between CRC stages Dukes' A and D. While the expression of PDE4D varied across CRC stages, the expression of SFRP5 remained consistently strong in both epithelium and lamina propria, with significant differences noted mainly in the lamina propria. The expression levels of PDE4B, PDE4D, and SFRP5 reveal significant differences in the expression of these genes between CRC patients and healthy controls, with notable implications for patient prognosis. Namely, our results demonstrate that PDE4B, PDE4D, and SFRP5 are significantly under-expressed in CRC tissues compared to control tissues. The Kaplan-Meier survival analysis and the log-rank (Mantel-Cox) test revealed distinct prognostic implications where patients with lower expression levels of SFRP5 exhibited significantly longer overall survival. The data align with our immunohistochemical results and might suggest a potential tumor-suppressive role for these genes in CRC. Conclusions: Considering significantly lower gene expression, aligned with our immunohistochemical data in tumor tissue in comparison to the control tissue, as well as the significantly poorer survival rate in the case of its higher expression, we can hypothesize that SFRP5 is the most promising biomarker for CRC out of the observed proteins. These findings suggest alterations in PDE4B, PDE4D, and SFRP5 expression during CRC progression, as well as between different stages of CRC, with potential implications for understanding the molecular mechanisms involved in CRC development and progression.

Role of MARCH E3 ubiquitin ligases in cancer development.

Membrane-associated RING-CH (MARCH) E3 ubiquitin ligases, a family of RING-type E3 ubiquitin ligases, have garnered increased attention for their indispensable roles in immune regulation, inflammation, mitochondrial dynamics, and lipid metabolism. The MARCH E3 ligase family consists of eleven distinct members, and the dysregulation of many of these members has been documented in several human malignancies. Over the past two decades, extensive research has revealed that MARCH E3 ligases play pivotal roles in cancer progression by ubiquitinating key oncogenes and tumor suppressors and orchestrating various signaling pathways. Some MARCH E3s act as oncogenes, while others act as tumor suppressors, and the majority of MARCH E3s play both oncogenic and tumor suppressive roles in a context-dependent manner. Notably, there is special emphasis on the sole mitochondrial MARCH E3 ligase MARCH5, which regulates mitochondrial homeostasis within cancer cells. In this review, we delve into the diverse functions of MARCH E3 ligases across different cancer types, shedding light on the underlying molecular mechanisms mediating their effects, their regulatory effects on cancer and their potential as therapeutic targets.

Down regulation of RBM10 promotes proliferation and metastasis via miR-224-5p/RBM10/p53 feedback loop in lung adenocarcinoma

RNA-binding motif protein 10 (RBM10) has a tumor suppressor role in multiple cancers. Combining Oncomine database results with tissue samples, Western blot analysis showed that RBM10 was significantly lower in lung adenocarcinoma (LUAD) than in adjacent normal tissues. Moreover, KM analysis revealed that the group with higher RBM10 expression in LUAD correlated with better overall survival (OS). Luciferase reporter assay revealed that an important tumor-promotive miRNA, miR-224-5p, was directly bound to the 3′UTR of RBM10, resulting in inhibition of RBM10 expression, and promoted LUAD progression both in vitro and in vivo. Mechanistically, we found that miR-224-5p directly targeted RBM10 to inhibit p53 expression during LUAD progression. Meanwhile, p53 affected RBM10 expression through p53/miR-224-5p axis. Our study identified RBM10 as a key tumor suppressor in the proliferation and metastasis of LUAD. The findings provide a novel mechanism involving a feedback loop of miR-224-5p/RBM10/p53 regulated tumor progression in LUAD, which may help with the design of more effective LUAD treatments.

N6-methyladenosine-modified ALDH9A1 modulates lipid accumulation and tumor progression in clear cell renal cell carcinoma through the NPM1/IQGAP2/AKT signaling pathway

Aldehyde dehydrogenases superfamily (ALDHs), which are ubiquitously present in various organisms with diverse subcellular localizations, play a crucial role in regulating malignant tumor progression; Nevertheless, their involvement in clear cell renal cell carcinoma (ccRCC) has not been elucidated. In this study, we performed comprehensive bioinformatics analyses on the 19 ALDHs genes, and identified ALDH9A1 as a key contributor in ccRCC. Expression patterns and clinical relevance of ALDH9A1 were determined using bioinformatics analyses, real-time PCR, western blotting, and immunohistochemistry. To explore the underlying mechanism behind the tumor suppressor role of ALDH9A1, RNA sequencing, methylated RNA immunoprecipitation, luciferase reporter assay, mass spectroscopy, immunoprecipitation, mutational studies and immunofluorescence were employed. The impact of ALDH9A1 in ccRCC progression and metabolic programming was assessed through both in vitro and in vivo. Here, this study revealed ALDH9A1 as a tumor suppressor gene in ccRCC. The fat mass and obesity associated protein (FTO) was identified as a demethylase for ALDH9A1 mRNA, resulting in its reduced stability and expression levels in ccRCC. Functional experiments demonstrated that the deficiency of ALDH9A1 in ccRCC promoted tumor proliferation, invasion, migration and lipid accumulation. Mechanistic insights illustrated that the diminished levels of ALDH9A1 resulted in the failure to sequester nucleophosmin 1 (NPM1) within cytoplasm, thereby suppressing the transcription of IQ motif containing the GTPase-activating protein 2 (IQGAP2), subsequently activating the AKT-mTOR signaling, ultimately fostering tumor progression and lipid accumulation. In conclusion, the present study highlights the robust prognostic significance of ALDH9A1 and delivers a comprehensive understanding of ALDH9A1-NPM1-IQGAP2-AKT axis in ccRCC. These findings established a solid research foundation for novel therapeutic strategies for ccRCC patients.

TAZ downregulated ANXA1 expression to modulate myeloma cell interactions with bone marrow mesenchymal stromal cells

We and others have previously shown that TAZ plays a tumor suppressive role in multiple myeloma. However, recent reports suggest that molecular crosstalk between the myeloma cells and bone marrow stromal components contributes to the myeloma cell survival and drug resistance. These reports further point to reciprocal interaction via adhesion molecules as the most prominent mechanism of intercellular crosstalk between myeloma cells and bone marrow mesenchymal stromal cells (BM-MSCs). YAP/TAZ silencing/expression has been shown to correlate across all cancers with a set of adhesion/extracellular matrix proteins. Therefore, we hypothesized that TAZ may regulate myeloma cell interaction with BM stromal cells by influencing the expression of distinct cell adhesion signatures. We used previously established TAZ myeloma cell line models, including DELTA47-pLENTI or TAZ knockout DELTA47 cells cocultured with or without BM-MSCs, as our study models. Using RNA sequencing analysis, we performed the first comprehensive screen for cell adhesion-related transcriptional targets of TAZ in multiple myeloma (MM). In doing so, we uncovered an enrichment of cell adhesion-related genes in TAZ knockout DELTA47 cells relatively to pLENTI-DELTA47 cells, including 11 genes with log2 fold change > 2 (p < 0.05), namely, ANXA1, ADGRL2, NCAM1, NCAM2, ADGRL3, CXADR, ALCAM, JAM2, KIRREL1, KIRREL2, and ADGRG7, suggesting possible relationship with TAZ. We validated ANXA1 as a bona fide target of TAZ in MM. We show that TAZ represses myeloma cell migration and interaction with BM-MSCs by transcriptionally downregulating ANXA1 expression via TEAD-dependent mechanism. Our data provide new insights into the understanding of the role of TAZ in the intercellular communication signals between myeloma cells and BM-MSCs. Our findings also suggest that ANXA1 represents a putative cell adhesion target to attenuate BM-MSC driven, tumor-promoting interaction with myeloma cells.

Drug resistant pancreatic cancer cells exhibit altered biophysical interactions with stromal fibroblasts in imaging studies of 3D co-culture models.

Interactions between tumor and stromal cells are well known to play a prominent roles in progression of pancreatic ductal adenocarcinoma (PDAC). As knowledge of stromal crosstalk in PDAC has evolved, it has become clear that cancer associated fibroblasts can play both tumor promoting and tumor suppressive roles through a combination of paracrine crosstalk and juxtacrine interactions involving direct physical contact. Another major contributor to dismal survival statistics for PDAC is development of resistance to chemotherapy drugs. Though less is known about how the acquisition of chemoresistance impacts upon tumor-stromal crosstalk. Here, we use 3D co-culture geometries to recapitulate juxtacrine interactions between epithelial and stromal cells. In particular, extracellular matrix (ECM) overlay cultures in which stromal cells (pancreatic stellate cells, or normal human fibroblasts) are placed adjacent to PDAC cells (PANC1), result in direct heterotypic cell adhesions accompanied by dramatic fibroblast contractility which leads to highly condensed macroscopic multicellular aggregates as detected using particle image velocimetry (PIV) analysis to quantify cell velocities over the course of time lapse movie sequences. To investigate how drug resistance impacts these juxtacrine interactions we contrast cultures in which PANC1 are substituted with a drug resistant subline (PANC1-OR) previously established in our lab. We find that heterotypic cell-cell interactions are highly suppressed in drug-resistant cells relative to the parental PANC1 cells. To investigate further we conduct RNA-seq and bioinformatics analysis to identify differential gene expression in PANC1 and PANC1-OR, which shows that negative regulation of cell adhesion molecules, consistent with increased epithelial mesenchymal transition (EMT), is also consistent with loss of hetrotypic cell-cell contact necessary for the contractile behavior observed in drug naïve cultures. Overall these findings elucidate the role of drug-resistance in inhibiting an avenue of stromal crosstalk which is associated with tumor suppression and also help to establish cell culture conditions useful for further mechanistic investigation.

Loss of monopolar spindle-binding protein 3B expression promotes colorectal cancer invasiveness by activation of target of rapamycin kinase/autophagy signaling.

Monopolar spindle-binding protein 3B (MOB3B) functions as a signal transducer and altered MOB3B expression is associated with the development of human cancers. To investigate the role of MOB3B in colorectal cancer (CRC). This study collected 102 CRC tissue samples for immunohistochemical detection of MOB3B expression for association with CRC prognosis. After overexpression and knockdown of MOB3B expression were induced in CRC cell lines, changes in cell viability, migration, invasion, and gene expression were assayed. Tumor cell autophagy was detected using transmission electron microscopy, while nude mouse xenograft experiments were performed to confirm the in-vitro results. MOB3B expression was reduced in CRC vs normal tissues and loss of MOB3B expression was associated with poor CRC prognosis. Overexpression of MOB3B protein in vitro attenuated the cell viability as well as the migration and invasion capacities of CRC cells, whereas knockdown of MOB3B expression had the opposite effects in CRC cells. At the molecular level, microtubule-associated protein light chain 3 II/I expression was elevated, whereas the expression of matrix metalloproteinase (MMP)2, MMP9, sequestosome 1, and phosphorylated mechanistic target of rapamycin kinase (mTOR) was downregulated in MOB3B-overexpressing RKO cells. In contrast, the opposite results were observed in tumor cells with MOB3B knockdown. The nude mouse data confirmed these in-vitro findings, i.e., MOB3B expression suppressed CRC cell xenograft growth, whereas knockdown of MOB3B expression promoted the growth of CRC cell xenografts. Loss of MOB3B expression promotes CRC development and malignant behaviors, suggesting a potential tumor suppressive role of MOB3B in CRC by inhibition of mTOR/autophagy signaling.