Loss of Expression of a Novel Chromatin Remodeler SMARCA1 in Soft Tissue Sarcoma

Targeting Chromatin-Remodeling Factors in Cancer Cells: Promising Molecules in Cancer Therapy

ATP-dependent chromatin-remodeling complexes can reorganize and remodel chromatin and thereby act as important regulator in various cellular processes. Based on considerable studies over the past two decades, it has been confirmed that the abnormal function of chromatin remodeling plays a pivotal role in genome reprogramming for oncogenesis in cancer development and/or resistance to cancer therapy. Recently, exciting progress has been made in the identification of genetic alteration in the genes encoding the chromatin-remodeling complexes associated with tumorigenesis, as well as in our understanding of chromatin-remodeling mechanisms in cancer biology. Here, we present preclinical evidence explaining the signaling mechanisms involving the chromatin-remodeling misregulation-induced cancer cellular processes, including DNA damage signaling, metastasis, angiogenesis, immune signaling, etc. However, even though the cumulative evidence in this field provides promising emerging molecules for therapeutic explorations in cancer, more research is needed to assess the clinical roles of these genetic cancer targets.

A pan-cancer bioinformatic analysis of the carcinogenic role of SMARCA1 in human carcinomas

SMARCA1is a mammalian imitation switch (ISWI) gene that encodes for SNF2L. SNF2L is involved in regulating cell transition from a committed progenitor state to a differentiated state. Although many papers have detailed the correlation between SMARCA1 and different cancers, no pan-cancer analysis has been conducted to date. We started by exploring the potential carcinogenic role of SMARCA1 across 33 carcinomas using the cancer genome atlas (TCGA) and the genotype-tissue expression (GTEx) databases. The expression of SMARCA1 was significantly elevated in some tumor types but not in others. There was a distinct relationship between SMARCA1 expression and patient prognosis. S116 phosphorylation levels were up-regulated in both lung adenocarcinoma and uterine corpus endometrial carcinoma. The expression level of SMARCA1 was positively correlated with cancer-associated fibroblasts infiltration in a number of tumors, such as colon adenocarcinoma, cervical squamous cell carcinoma and endocervical adenocarcinoma. It was also associated with CD8+ T-cell infiltration in head and neck squamous cell carcinoma and lung adenocarcinoma. Furthermore, SMARCA1 is involved in chromatin remodeling and protein processing-associated mechanisms. Our study presents an initial assessment and illustration of the carcinogenic role of SMARCA1 in different carcinomas.

ARP-T1-associated Bazex-Dupré-Christol syndrome is an inherited basal cell cancer with ciliary defects characteristic of ciliopathies

Actin-Related Protein-Testis1 (ARP-T1)/ACTRT1 gene mutations cause the Bazex-Dupré-Christol Syndrome (BDCS) characterized by follicular atrophoderma, hypotrichosis, and basal cell cancer. Here, we report an ARP-T1 interactome (PXD016557) that includes proteins involved in ciliogenesis, endosomal recycling, and septin ring formation. In agreement, ARP-T1 localizes to the midbody during cytokinesis and the basal body of primary cilia in interphase. Tissue samples from ARP-T1-associated BDCS patients have reduced ciliary length. The severity of the shortened cilia significantly correlates with the ARP-T1 levels, which was further validated by ACTRT1 knockdown in culture cells. Thus, we propose that ARP-T1 participates in the regulation of cilia length and that ARP-T1-associated BDCS is a case of skin cancer with ciliopathy characteristics.

Park et al. characterise the interactome, localisation and function of Actin-Related Protein-Testis1 protein (ARP-T1), encoded by the ACTRT1 gene, associated with inherited basal cell cancer. They find that ARP-T1 is localised to the primary cilia basal body in epidermal cells, interacts with the cilia machinery, and is needed for proper ciliogenesis.

FOXC1 Downregulates Nanog Expression by Recruiting HDAC2 to Its Promoter in F9 Cells Treated by Retinoic Acid

FOXC1, a transcription factor involved in cell differentiation and embryogenesis, is demonstrated to be a negative regulator of Nanog in this study. FOXC1 is up-regulated in retinoic acid-induced differentiation of F9 Embryonal Carcinoma (EC) cells; furthermore, FOXC1 specifically inhibits the core pluripotency factor Nanog by binding to the proximal promoter. Overexpression of FOXC1 in F9 or knockdown in 3T3 results in the down-regulation or up-regulation of Nanog mRNA and proteins, respectively. In order to explain the mechanism by which FOXC1 inhibits Nanog expression, we identified the co-repressor HDAC2 from the FOXC1 interactome. FOXC1 recruits HDAC2 to Nanog promoter to decrease H3K27ac enrichment, resulting in transcription inhibition of Nanog. To the best of our knowledge, this is the first report that FOXC1 is involved in the epigenetic regulation of gene expression.