UBCH5 Family Members Differentially Impact Stabilization of Mutant p53 via RNF128 Iso1 During Barrett's Progression to Esophageal Adenocarcinoma

Differences in Gender and Overall Survival for Temperature-Sensitive TP53 Mutations in Gastroesophageal Cancer

Background and Objectives: Temperature-sensitive (TS) mutants of TP53 are thermally unstable, unfolded, and inactive at body temperature but can be refolded and reactivated at sub-physiological temperatures. TS TP53 may be amenable for functional rescue by hypothermia or structure-stabilizing drugs, and may retain low-level transcriptional activity at 37 °C. TP53 mutations are observed in 47% of all esophageal cancers (ECs) and 25% to 40% of gastric cancers (GCs). We aimed to investigate the trends and outcomes of EC and GC with TS TP53 mutations using cBioportal. We hypothesize that TS TP53 mutants in EC and GC present a unique prognostic profile distinct from non-TS TP53 mutants, potentially affecting overall survival and cancer progression. Materials and Methods: We identified 1924 patients from cBioportal with GC or EC, harboring any TP53 mutation. Patients were then stratified based on the TP53 temperature sensitivity according to a recently reported functional analysis of its activity. Patients were also stratified based on a history of Barrett's esophagus (BE), cancer stage, sex, and race. We then compared populations (TS vs. non-TS TP53) to assess differences and evaluated survival outcomes. Results: Males represented 77% of the cohort, and 51.6% of the samples were from patients with stage IV cancer. No association was found between TS vs. non-TS mutational status and BE, cancer stage, or race. Interestingly, a significantly higher proportion of females (22.9%) than males (14.5%) displayed a TS TP53 mutation (p = 0.012). No significant difference was seen in overall survival between the TS and non-TS mutations capable of ≥50% growth suppression at 32 °C (median = 33 vs. 28 months, p = 0.36). This trend was also observed when the patients were filtered based on cancer location. The median survival for EC was 32.5 months compared to 33 months (p = 0.67). In cases of GC, median survival times could not be determined due to the insufficient number of events. Conclusions: Although no statistical significance was observed, a decrease in overall survival for patients with TS TP53 mutations was noted. The result is counterintuitive given that TS mutants have less severe structural destabilization and suggests TS TP53 mutations may have a unique prognostic value that warrants further investigation.

GRAIL1 Stabilizes Misfolded Mutant p53 through a Ubiquitin Ligase-Independent, Chaperone Regulatory Function

Frequent (>70%) TP53 mutations often promote its protein stabilization, driving esophageal adenocarcinoma (EAC) development linked to poor survival and therapy resistance. We previously reported that during Barrett's esophagus progression to EAC, an isoform switch occurs in the E3 ubiquitin ligase RNF128 (aka GRAIL-gene related to anergy in lymphocytes), enriching isoform 1 (hereby GRAIL1) and stabilizing the mutant p53 protein. Consequently, GRAIL1 knockdown degrades mutant p53. But, how GRAIL1 stabilizes the mutant p53 protein remains unclear. In search for a mechanism, here, we performed biochemical and cell biology studies to identify that GRAIL has a binding domain (315-PMCKCDILKA-325) for heat shock protein 40/DNAJ. This interaction can influence DNAJ chaperone activity to modulate misfolded mutant p53 stability. As predicted, either the overexpression of a GRAIL fragment (Frag-J) encompassing the DNAJ binding domain or a cell-permeable peptide (Pep-J) encoding the above 10 amino acids can bind and inhibit DNAJ-Hsp70 co-chaperone activity, thus degrading misfolded mutant p53. Consequently, either Frag-J or Pep-J can reduce the survival of mutant p53 containing dysplastic Barrett's esophagus and EAC cells and inhibit the growth of patient-derived organoids of dysplastic Barrett's esophagus in 3D cultures. The misfolded mutant p53 targeting and growth inhibitory effects of Pep-J are comparable with simvastatin, a cholesterol-lowering drug that can degrade misfolded mutant p53 also via inhibiting DNAJA1, although by a distinct mechanism. Implications: We identified a novel ubiquitin ligase-independent, chaperone-regulating domain in GRAIL and further synthesized a first-in-class novel misfolded mutant p53 degrading peptide having future translational potential.

UBE2D1 promotes glioblastoma proliferation by modulating p21 ubiquitination

Glioblastoma (GBM) cells exhibit aberrant proliferative abilities and resistance to conventional therapies. However, the mechanisms underlying these malignant phenotypes are poorly understood. In this study, we identified ubiquitin-conjugating enzyme E2D1 (UBE2D1) as a crucial stimulator of GBM development. It is highly expressed in GBM and closely associated with poor prognosis in patients with GBM. UBE2D1 knockdown inhibits GBM cell growth and leads to G1 cell cycle arrest. Mechanistically, UBCH5A binds to p21 at the protein level and induces the ubiquitination and degradation of p21. This negative regulation is mediated by STUB1. Our findings are the first to identify UBE2D1 as a key driver of GBM growth and provide a potential target for improving prognosis and therapy.

Downregulation of RNF128 Inhibits the Proliferation, Migration, Invasion and EMT of Colorectal Cancer Cells

Colorectal cancer has the third highest incidence and second highest mortality rate among all cancer types. Exploring the molecular mechanisms driving malignant proliferation and metastasis of colorectal cancer will benefit the treatment and management of cancer patients. Recent studies have reported diametrically opposed roles of Ring finger protein 128 (RNF128) in different types of cancer. However, the role of RNF128 in colorectal cancer is still completely unknown, which this study attempts to analyze. The differential expression of RNF128 mRNA and protein in 30 pairs of colorectal cancer and corresponding peritumoral tissues was detected using RT-qPCR, western blot and immunohistochemical staining. siRNA specifically targeting RNF128 was transfected into colorectal cancer cell lines (SW1116 and SW480) cultured in vitro. Proliferation, growth, migration, invasion and epithelial-mesenchymal transition (EMT) of colorectal cancer cells were examined by CCK-8, clone formation, wound-healing, transwell, western blot and immunofluorescence assays. Both RNF128 mRNA and protein levels were significantly increased in colorectal cancer tissues compared to pericarcinoma tissues. Knockdown of RNF128 significantly inhibited the proliferation, growth, migration, invasion and EMT of SW480 and SW1116 cells. Targeting RNF128 may benefit the treatment and management of colorectal cancer.

ISG15/GRAIL1/CD3 axis influences survival of patients with esophageal adenocarcinoma

Immunosuppression is a common feature of esophageal adenocarcinoma (EAC) and has been linked to poor overall survival (OS). We hypothesized that upstream factors might negatively influence CD3 levels and T cell activity, thus promoting immunosuppression and worse survival. We used clinical data and patient samples of those who progressed from Barrett's to dysplasia to EAC, investigated gene (RNA-Seq) and protein (tissue microarray) expression, and performed cell biology studies to delineate a pathway impacting CD3 protein stability that might influence EAC outcome. We showed that the loss of both CD3-ε expression and CD3+ T cell number correlated with worse OS in EAC. The gene related to anergy in lymphocytes isoform 1 (GRAIL1), which is the prominent isoform in EACs, degraded (ε, γ, δ) CD3s and inactivated T cells. In contrast, isoform 2 (GRAIL2), which is reduced in EACs, stabilized CD3s. Further, GRAIL1-mediated CD3 degradation was facilitated by interferon-stimulated gene 15 (ISG15), a ubiquitin-like protein. Consequently, the overexpression of a ligase-dead GRAIL1, ISG15 knockdown, or the overexpression of a conjugation-defective ISG15-leucine-arginine-glycine-glycine mutant could increase CD3 levels. Together, we identified an ISG15/GRAIL1/mutant p53 amplification loop negatively influencing CD3 levels and T cell activity, thus promoting immunosuppression in EAC.

Isoform alterations in the ubiquitination machinery impacting gastrointestinal malignancies

The advancement of RNAseq and isoform-specific expression platforms has led to the understanding that isoform changes can alter molecular signaling to promote tumorigenesis. An active area in cancer research is uncovering the roles of ubiquitination on spliceosome assembly contributing to transcript diversity and expression of alternative isoforms. However, the effects of isoform changes on functionality of ubiquitination machineries (E1, E2, E3, E4, and deubiquitinating (DUB) enzymes) influencing onco- and tumor suppressor protein stabilities is currently understudied. Characterizing these changes could be instrumental in improving cancer outcomes via the identification of novel biomarkers and targetable signaling pathways. In this review, we focus on highlighting reported examples of direct, protein-coded isoform variation of ubiquitination enzymes influencing cancer development and progression in gastrointestinal (GI) malignancies. We have used a semi-automated system for identifying relevant literature and applied established systems for isoform categorization and functional classification to help structure literature findings. The results are a comprehensive snapshot of known isoform changes that are significant to GI cancers, and a framework for readers to use to address isoform variation in their own research. One of the key findings is the potential influence that isoforms of the ubiquitination machinery have on oncoprotein stability.

IGF2BP2-modified UBE2D1 interacts with Smad2/3 to promote the progression of breast cancer

Recent studies have suggested that ubiquitin-conjugating enzyme E2D1 (UBE2D1) is involved in tumor progression. In this study, we found that UBE2D1 expression was upregulated in breast cancer (BC) and was related to the prognosis of BC patients. Through in vitro and in vivo experiments, we demonstrated the aberrant expression of UBE2D1 promoted the proliferation and migration of BC cells, and the IGF2BP2-mediated N6-methyladenosine (m6A) modification increased the stability of UBE2D1 mRNA. Mechanistically, UBE2D1 expression regulated the activity of TGF-β signaling through modulating the expression and the phosphorylation level of Smad2/3. Furthermore, UBE2D1 directly bound to Smad2/3 and affected the subsequent binding of Smad2 and Smad3, which is a necessary step for TGF-β signaling activation. Thus, our study reveals a pro-oncogenic role of UBE2D1 in the progression of BC and may provide novel strategies for BC treatment.

Towards artificial intelligence to multi-omics characterization of tumor heterogeneity in esophageal cancer

Esophageal cancer is a unique and complex heterogeneous malignancy, with substantial tumor heterogeneity: at the cellular levels, tumors are composed of tumor and stromal cellular components; at the genetic levels, they comprise genetically distinct tumor clones; at the phenotypic levels, cells in distinct microenvironmental niches acquire diverse phenotypic features. This heterogeneity affects almost every process of esophageal cancer progression from onset to metastases and recurrence, etc. Intertumoral and intratumoral heterogeneity are major obstacles in the treatment of esophageal cancer, but also offer the potential to manipulate the heterogeneity themselves as a new therapeutic strategy. The high-dimensional, multi-faceted characterization of genomics, epigenomics, transcriptomics, proteomics, metabonomics, etc. of esophageal cancer has opened novel horizons for dissecting tumor heterogeneity. Artificial intelligence especially machine learning and deep learning algorithms, are able to make decisive interpretations of data from multi-omics layers. To date, artificial intelligence has emerged as a promising computational tool for analyzing and dissecting esophageal patient-specific multi-omics data. This review provides a comprehensive review of tumor heterogeneity from a multi-omics perspective. Especially, we discuss the novel techniques single-cell sequencing and spatial transcriptomics, which have revolutionized our understanding of the cell compositions of esophageal cancer and allowed us to determine novel cell types. We focus on the latest advances in artificial intelligence in integrating multi-omics data of esophageal cancer. Artificial intelligence-based multi-omics data integration computational tools exert a key role in tumor heterogeneity assessment, which will potentially boost the development of precision oncology in esophageal cancer.