DAB2IP modulates primary cilia formation associated with renal tumorigenesis

A Systematic Analysis of Expression and Function of RAS GTPase-Activating Proteins (RASGAPs) in Urological Cancers: A Mini-Review

The RAS signaling pathway is one of the most commonly dysregulated pathways in urological cancers. This pathway can be regulated by RASGAPs, which catalyze the hydrolysis of RAS-GTP to RAS-GDP. As such, the loss of RASGAPs can promote the activation of the RAS signaling pathway. Dysregulation of RASGAPs significantly contributes to the progression of urological cancers, including prostate cancer, bladder cancer, and renal cell carcinoma. Furthermore, alterations in RASGAP expression may influence sensitivity to chemotherapy, radiotherapy, and targeted therapies, suggesting their potential as therapeutic targets. Despite the challenges involved, a deeper understanding of the complexity of the RAS signaling network, along with the evolution of personalized medicine, holds promise for delivering more precise and effective treatment options targeting RASGAPs in urological cancers.

Kidney cancer: From tumor biology to innovative therapeutics

Renal cell carcinoma (RCC) constitutes the most frequent kidney cancer of the adult population and one of the most lethal malignant tumors worldwide. RCC often presents without early symptoms, leading to late diagnosis. Prognosis varies widely based on the stage of cancer at diagnosis. In the early-stage, localized RCC has a relatively good prognosis, while advanced or metastatic RCC has a poor outcome. Obesity, smoking, genetic mutations and family history are all considered risk factors for RCC, while inherited disorders, such as Tuberous Sclerosis and von Hippel-Lindau syndrome, are causally associated with RCC development. Genetic screening, deep sequencing analysis, quantitative proteomics and immunostaining analysis on RCC tissues, biological fluids and blood samples have been employed to identify novel biomarkers, predisposing factors and therapeutic targets for RCC with important clinical implications for patient treatment. Combined approaches of gene-targeting strategies coupled to a deep functional analysis of cancer cell biology, both in vitro and in appropriate animal models of RCC, significantly contributed to identify and characterize relevant pathogenic mechanisms underlying development and progression of RCC. These studies provided also important cues for the generation of novel target-specific therapeutics that selectively restore deranged cancer cell signalling and dysfunctional immune checkpoints, positively impacting on the survival rate of treated RCC patients. In this review, we will describe the recent discoveries concerning the most relevant pathogenic mechanisms of RCC and will highlight novel therapeutic strategies that interrupt oncogenic pathways and restore immune defences in RCC patients.

An update on the tumor-suppressive functions of the RasGAP protein DAB2IP with focus on therapeutic implications

The dynamic crosstalk between tumor and stromal cells is a major determinant of cancer aggressiveness. The tumor-suppressor DAB2IP (Disabled homolog 2 interacting protein) plays an important role in this context, since it modulates cell responses to multiple extracellular inputs, including inflammatory cytokines and growth factors. DAB2IP is a RasGAP and negatively controls Ras-dependent mitogenic signals. In addition, it modulates other major oncogenic pathways, including TNFα/NF-κB, WNT/β-catenin, PI3K/AKT, and androgen receptor signaling. In line with its tumor-suppressive role, DAB2IP is frequently inactivated in cancer by transcriptional and post-transcriptional mechanisms, including promoter methylation, microRNA-mediated downregulation, and protein-protein interactions. Intriguingly, some observations suggest that downregulation of DAB2IP in cells of the tumor stroma could foster establishment of a pro-metastatic microenvironment. This review summarizes recent insights into the tumor-suppressive functions of DAB2IP and the consequences of its inactivation in cancer. In particular, we explore potential approaches aimed at reactivating DAB2IP, or augmenting its expression levels, as a novel strategy in cancer treatment. We suggest that reactivation or upregulation of DAB2IP would concurrently attenuate multiple oncogenic pathways in both cancer cells and the tumor microenvironment, with implications for improved treatment of a broad spectrum of tumors.

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.

Abnormal accumulation of OFD1 in endometrial cancer with poor prognosis inhibits ciliogenesis

The aim of the present study was to examine primary cilia in endometrial tissue during the menstrual cycle and to clarify their morphological changes with different grades of endometrial cancer. Images of fluorescence immunostaining taken by confocal microscopy were used to count the number of primary cilia in normal endometrium and endometrioid carcinoma Grade 1 and Grade 3 specimens. To examine the association between autophagy and ciliogenesis in endometrioid carcinoma, the expression of p62/Sequestosome-1, a selective substrate for autophagy, and oral-facial-digital syndrome 1 protein (OFD1), a protein associated with ciliogenesis, were examined using images of fluorescence immunostaining taken by confocal microscopy. The level of p62 expression was confirmed by western blotting. In proliferative and secretory endometrial stromal cells, the percentage of cells that were ciliated was 7.2 and 32.7% (95% confidence interval=21.61-39.79; P<0.01), and the length of the primary cilia was 1.24 µm and 2.34 µm (0.92-1.26; P<0.01), respectively. In stromal cells of endometrioid carcinoma Grade 1 and Grade 3, the percentage of ciliated cells was 13.5 and 2.9% (7.89-15.05; P<0.001), and the length of the primary cilia was 2.02 and 1.14 µm (0.76-0.99; P<0.001), respectively. In both normal menstrual cycle tissue and endometrial carcinomas, the percentage of primary cilia was lower and their length was shorter in tissues with higher proliferative potential. The expression of OFD1 was significantly higher in Grade 3 compared with Grade 1 as indicated by quantifying the intensity of the fluorescence images (133–12248; P=0.046). To the best of our knowledge, this is the first study concerning the distribution of primary cilia in normal endometrium and endometrial cancer tissues. Overall, fewer ciliated cells in the highly malignant endometrial cancer tissues may be associated not only to the proliferation of cancer cells, but also to the excessive accumulation of OFD1 due to dysfunctional autophagy.

Role of primary cilia and Hedgehog signaling in craniofacial features of Ellis-van Creveld syndrome

Ellis-van Creveld syndrome (EvC) is an autosomal recessive genetic disorder involving pathogenic variants of EVC and EVC2 genes and classified as a ciliopathy. The syndrome is caused by mutations in the EVC gene on chromosome 4p16, and EVC2 gene, located close to the EVC gene, in a head-to-head configuration. Regardless of the affliction of EVC or EVC2, the clinical features of Ellis-van Creveld syndrome are similar. Both these genes are expressed in tissues such as, but not limited to, the heart, liver, skeletal muscle, and placenta, while the predominant expression in the craniofacial tissues is that of EVC2. Biallelic mutations of EVC and EVC2 affect Hedgehog signaling and thereby ciliary function, crucial factors in vertebrate development, culminating in the phenotypical features characteristic of EvC. The clinical features of Ellis-van Creveld syndrome are consistent with significant abnormalities in morphogenesis and differentiation of the affected tissues. The robust role of primary cilia in histodifferentiation and morphodifferentiation of oral, perioral, and craniofacial tissues is becoming more evident in the most recent literature. In this review, we give a summary of the mechanistic role of primary cilia in craniofacial development, taking Ellis-van Creveld syndrome as a representative example.