Loss of Dab2 expression in breast cancer cells impairs their ability to deplete TGF-β and induce Tregs development via TGF-β

The scaffold protein disabled 2 (DAB2) and its role in tumor development and progression

BACKGROUND

Disabled 2 (DAB2) is a multifunctional protein that has emerged as a critical component in the regulation of tumor growth. Its dysregulation is implicated in various types of cancer, underscoring its importance in understanding the molecular mechanisms underlying tumor development and progression. This review aims to unravel the intricate molecular mechanisms by which DAB2 exerts its tumor-suppressive functions within cancer signaling pathways.

METHODS AND RESULTS

We conducted a comprehensive review of the literature focusing on the structure, expression, physiological functions, and tumor-suppressive roles of DAB2. We provide an overview of the structure, expression, and physiological functions of DAB2. Evidence supporting DAB2's role as a tumor suppressor is explored, highlighting its ability to inhibit cell proliferation, induce apoptosis, and modulate key signaling pathways involved in tumor suppression. The interaction between DAB2 and key oncogenes is examined, elucidating the interplay between DAB2 and oncogenic signaling pathways. We discuss the molecular mechanisms underlying DAB2-mediated tumor suppression, including its involvement in DNA damage response and repair, regulation of cell cycle progression and senescence, and modulation of epithelial-mesenchymal transition (EMT). The review explores the regulatory networks involving DAB2, covering post-translational modifications, interactions with other tumor suppressors, and integration within complex signaling networks. We also highlight the prognostic significance of DAB2 and its role in pre-clinical studies of tumor suppression.

CONCLUSION

This review provides a comprehensive understanding of the molecular mechanisms by which DAB2 exerts its tumor-suppressive functions. It emphasizes the significance of DAB2 in cancer signaling pathways and its potential as a target for future therapeutic interventions.

Disable 2, A Versatile Tissue Matrix Multifunctional Scaffold Protein with Multifaceted Signaling: Unveiling Role in Breast Cancer for Therapeutic Revolution

The Disabled-2 (DAB2) protein, found in 80-90% of various tumors, including breast cancer, has been identified as a potential tumor suppressor protein. On the contrary, some hypothesis suggests that DAB2 is associated with the modulation of the Ras/MAPK pathway by endocytosing the Grb/Sos1 signaling complex, which produces oncogenes and chemoresistance to anticancer drugs, leading to increased tumor growth and metastasis. DAB2 has multiple functions in several disorders and is typically under-regulated in several cancers, making it a potential target for treatment of cancer therapy. The primary function of DAB2 is the modulation of transforming growth factor- β (TGF-β) mediated endocytosis, which is involved in several mechanisms of cancer development, including tumor suppression through promoting apoptosis and suppressing cell proliferation. In this review, we will discuss in detail the mechanisms through which DAB2 leads to breast cancer and various advancements in employing DAB2 in the treatment of breast cancer. Additionally, we outlined its role in other diseases. We propose that upregulating DAB2 could be a novel approach to the therapeutics of breast cancer.

Identification and Validation of a Prognostic Signature Based on Methylation Profiles and Methylation-Driven Gene DAB2 as a Prognostic Biomarker in Differentiated Thyroid Carcinoma

Recurrence is the major death cause of differentiated thyroid carcinoma (DTC), and a better understanding of recurrence risk at early stage may lead to make the optimal medical decision to improve patients’ prognosis. The 2015 American Thyroid Association (ATA) risk stratification system primary based on clinic-pathologic features is the most commonly used to describe the initial risk of persistent/recurrent disease. Besides, multiple prognostics models based on multigenes expression profiles have been developed to predict the recurrence risk of DTC patients. Recent evidences indicated that aberrant DNA methylation is involved in the initiation and progression of DTC and can be useful biomarkers for clinical diagnosis and prognosis prediction of DTC. Therefore, there is a need for integrating gene methylation feature to assess the recurrence risk of DTC. Gene methylation profile from The Cancer Genome Atlas (TCGA) was used to construct a recurrence risk model of DTC by successively performed univariate Cox regression, LASSO regression, and multivariate Cox regression. Two Gene Expression Omnibus (GEO) methylation cohorts of DTC were utilized to validate the predictive value of the methylation profiles model as external cohort by receiver operating characteristic (ROC) curve and survival analysis. Besides, CCK-8, colony-formation assay, transwell, and scratch-wound assay were used to investigate the biological significance of critical gene in the model. In our study, we constructed and validated a prognostic signature based on methylation profiles of SPTA1, APCS, and DAB2 and constructed a nomogram based on the methylation-related model, age, and AJCC_T stage that could provide evidence for the long-term treatment and management of DTC patients. Besides, in vitro experiments showed that DAB2 inhibited proliferation, colony-formation, and migration of BCPAP cells and the gene set enrichment analysis and immune infiltration analysis showed that DAB2 may promote antitumor immunity in DTC. In conclusion, promoter hypermethylation and loss expression of DAB2 in DTC may be a biomarker of unfavorable prognosis and poor response to immune therapy.

Involvement of Disabled-2 on skin fibrosis in systemic sclerosis

BACKGROUND

Systemic sclerosis (SSc) is a connective tissue disease characterized by inflammation and fibrosis. Our previous research found Disabled-2 (DAB2) expression was significantly downregulated by salvianolic acid B, a small molecular medicine which attenuated experimental skin fibrosis of SSc. These suggest that DAB2 plays an important role in SSc skin fibrosis, but the role of DAB2 in SSc remains unclear.

OBJECTIVES

To investigate the role of DAB2 in SSc.

METHODS

DAB2 expression level was detected in the skin and peripheral blood mononuclear cells of SSc patients. Bleomycin (BLM)-induced SSc mice and primary SSc skin fibroblasts were used to investigate the effect of DAB2 downregulation on fibrosis. RNA-seq transcriptome analysis was performed to underlie the mechanism of DAB2 in fibroblasts.

RESULTS

DAB2 expression was enhanced in SSc lesion skin and was positively correlated with fibrotic genes, such as α-SMA and PAI-1. The in vivo study revealed that DAB2 downregulation alleviated skin fibrosis, alleviating skin thickness and reducing collagen deposition, and DAB2 knockdown ameliorated the inflammatory cell infiltration. The in vitro study showed that DAB2 knockdown reduced extracellular matrix genes and proteins expression. Moreover, Transcriptome analysis revealed TGF-β and focal adhesion signaling pathways were the main downregulated pathways involved in DAB2 siRNA treated fibroblasts.

CONCLUSIONS

Taken together, our results revealed that DAB2 was increased in SSc skin, and DAB2 downregulation inhibited BLM-induced mouse skin fibrosis and SSc skin fibroblasts activation. DAB2 played an important role in the pathogenesis of SSc and DAB2 modulation may represent a potential therapeutic method for SSc.

Loss of Disabled-2 Expression in Pancreatic Cancer Progression

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer type characterized by rapid metastasis and resistance to chemotherapy, properties that are shared by cancer stem cells (CSCs). In pancreatic cancer, tumor cells which possess the properties of CSCs also phenotypically resemble cells that have undergone epithelial-to-mesenchymal transition or EMT. Disabled-2 (Dab2) is a multifunctional scaffold protein frequently downregulated in cancer that has been linked to the process of EMT. However, the role of Dab2 in pancreatic cancer development and progression remains unclear. Downregulation of Dab2 expression in pancreatic cancer cell lines was found to trigger induction of genes characteristic of EMT and the CSC phenotype, while overexpression of Dab2 in the Panc1 cell line blocked the process of TGFβ-stimulated EMT. In addition, selective inhibition of the TGFβRI/RII receptors was found to reverse genes altered by Dab2 downregulation. Dab2 mRNA expression was found to be decreased in PDAC tumor samples, as compared to levels observed in normal pancreatic tissue. Methylation of the Dab2 gene promoter was demonstrated in Stage I PDAC tumors and in the MiaPaCa2 cell line, suggesting that promoter methylation may silence Dab2 expression early in pancreatic cancer progression. These results suggest that Dab2 may function as a tumor suppressor in pancreatic cancer by modulation of the TGFβ-stimulated EMT and CSC phenotype.

miR-106b targets DAB2 to promote hepatocellular carcinoma cell proliferation and metastasis

MicroRNAs (miRNAs) have been proven to have important effects on the proliferation and metastasis of multiple cancers, including hepatocellular carcinoma (HCC). In the present study, our aim was to explore the biological function of miR-106b in HCC cell proliferation and metastasis. qPCR analysis showed that miR-106b was expressed at higher levels, while disabled homolog 2 (DAB2) was expressed at lower levels in HCC tissues and cells. Moreover, the aberrant miR-106b expression in HCC affected the cell proliferative and migratory ability by MTT and Transwell assay. DAB2 was identified as a specific target of miR-106b in HCC by luciferase reporter assay and regression analysis showed a negative correlation between DAB2 and miR-106b expression. In addition, DAB2 may attenuate the miR-106b promotion effect on HCC cell proliferation and migration. In short, miR-106b may promote HCC cell proliferation and migration by targeting DAB2.

Switching Roles of TGF-β in Cancer Development: Implications for Therapeutic Target and Biomarker Studies

TGF-β induces complicated and even opposite responses in numerous biological processes, e.g., tumor suppression in pre-malignant cells and metastasis promotion in cancer cells. However, the cellular contextual determinants of these different TGF-β roles remain elusive, and the driver genes triggering the determinants’ changes have not been identified. Recently, however, several findings have provided new insights on the contextual determinants of Smads in TGF-β’s biological processes. These novel switches and their effectors may serve as prognostic biomarkers and therapeutic targets of TGF-β-mediated cancer progression.

Integrin traffic - the update

Integrins are a family of transmembrane cell surface molecules that constitute the principal adhesion receptors for the extracellular matrix (ECM) and are indispensable for the existence of multicellular organisms. In vertebrates, 24 different integrin heterodimers exist with differing substrate specificity and tissue expression. Integrin–extracellular-ligand interaction provides a physical anchor for the cell and triggers a vast array of intracellular signalling events that determine cell fate. Dynamic remodelling of adhesions, through rapid endocytic and exocytic trafficking of integrin receptors, is an important mechanism employed by cells to regulate integrin–ECM interactions, and thus cellular signalling, during processes such as cell migration, invasion and cytokinesis. The initial concept of integrin traffic as a means to translocate adhesion receptors within the cell has now been expanded with the growing appreciation that traffic is intimately linked to the cell signalling apparatus. Furthermore, endosomal pathways are emerging as crucial regulators of integrin stability and expression in cells. Thus, integrin traffic is relevant in a number of pathological conditions, especially in cancer. Nearly a decade ago we wrote a Commentary in Journal of Cell Science entitled ‘Integrin traffic’. With the advances in the field, we felt it would be appropriate to provide the growing number of researchers interested in integrin traffic with an update.

Dab2, a negative regulator of DC immunogenicity, is an attractive molecular target for DC-based immunotherapy

Dab2 is an adapter protein involved in receptor-mediated signaling, endocytosis, cell adhesion, hematopoietic cell differentiation, and angiogenesis. It plays a pivotal role in controlling cellular homeostasis. In the immune system, the Dab2 is a Foxp3 target gene and is required for regulatory T (Treg) cell function. Dab2 expression and its biological function in dendritic cells (DCs) have not been described. In this study, we found that Dab2 was significantly induced during the development of mouse bone marrow (BM)-derived DCs (BMDCs) and human monocyte-derived DCs (MoDCs). Even in a steady state, Dab2 was expressed in mouse splenic DCs (spDCs). STAT5 activation, Foxp3 expression, and hnRNPE1 activation mediated by PI3K/Akt signaling were required for Dab2 expression during GM-CSF-derived BMDC development regardless of TGF-β signaling. Dab2-silencing was accompanied by enhanced IL-12 and IL-6 expression, and an improved capacity of DC for antigen uptake, migration and T cell stimulation, which generated strong CTL in vaccinated mice. Vaccination with Dab2-silenced DCs inhibited tumor growth more effectively than did vaccination with wild type DCs. Dab2-overexpression abrogated the efficacy of the DC vaccine in DC-based tumor immunotherapy. These data strongly suggest that Dab2 might be an intrinsic negative regulator of the immunogenicity of DCs, thus might be an attractive molecular target to improve DC vaccine efficacy.