WNT-Regulated Transcriptional Enhancers and Stem Cell Plasticity

Safely Targeting Cancer, the Wound That Never Heals, Utilizing CBP/Beta-Catenin Antagonists

Stem cells, both normal somatic (SSC) and cancer stem cells (CSC) exist in minimally two states, i.e., quiescent and activated. Regulation of these two states, including their reliance on different metabolic processes, i.e., FAO and glycolysis in quiescent versus activated stem cells respectively, involves the analysis of a complex array of factors (nutrient and oxygen levels, adhesion molecules, cytokines, etc.) to initiate the epigenetic changes to either depart or enter quiescence. Quiescence is a critical feature of SSC that is required to maintain the genomic integrity of the stem cell pool, particularly in long lived complex organisms. Quiescence in CSC, whether they are derived from mutations arising in SSC, aberrant microenvironmental regulation, or via dedifferentiation of more committed progenitors, is a critical component of therapy resistance and disease latency and relapse. At the beginning of vertebrate evolution, approximately 450 million years ago, a gene duplication generated the two members of the Kat3 family, CREBBP (CBP) and EP300 (p300). Despite their very high degree of homology, these two Kat3 coactivators play critical and non-redundant roles at enhancers and super-enhancers via acetylation of H3K27, thereby controlling stem cell quiescence versus activation and the cells metabolic requirements. In this review/perspective, we discuss the unique regulatory roles of CBP and p300 and how specifically targeting the CBP/β-catenin interaction utilizing small molecule antagonists, can correct lineage infidelity and safely eliminate quiescent CSC.

OTUD7B promotes cell migration and invasion, predicting poor prognosis of gastric cancer

BACKGROUND

OTUD7B, a member of the ovarian tumor (OTU) protein superfamily, functions as a deubiquitinating enzyme and is associated with various biological processes and disease conditions, including tumors. In this study, we aimed to explore the expression patterns, prognostic significance, and the functional roles and underlying mechanisms of OTUD7B in gastric cancer (GC).

MATERIALS AND METHODS

Using a blend of bioinformatics, clinical case reviews, and molecular experiments, we evaluated the expression of OTUD7B in GC at both mRNA and protein levels. We examined the relationship between OTUD7B expression and clinicopathological characteristics of GC patients. Additionally, in vitro assays were utilized to assess the effects of OTUD7B on the migratory and invasive capabilities of GC cells. RNA sequencing analysis was conducted to identify critical genes and pathways linked to OTUD7B in GC.

RESULTS

OTUD7B was found to be significantly overexpressed in GC, both at mRNA and protein levels. Higher levels of OTUD7B were positively associated with advanced tumor TNM stage, higher histological grade, and presence of lymph/vein invasion. These correlations were indicative of poorer overall survival (OS) and disease-free survival (DFS) in GC patients. In vitro assays revealed that genetic knockout of OTUD7B markedly reduced the migration and invasion of GC cells, while overexpression of OTUD7B led to enhanced cellular migration and invasion. Furthermore, RNA sequencing and bioinformatic analyses indicated that the absence of OTUD7B suppressed signaling pathways related to cancer progression, metastasis, and metabolism. Mechanistically, OTUD7B likely promotes GC metastasis through the WNT signaling pathway, specifically targeting β-catenin.

CONCLUSIONS

OTUD7B serves as a novel marker for poor prognosis in GC and actively promotes tumor metastasis. Our results shed light on the signaling pathways regulated by OTUD7B and highlight potential targets for therapeutic intervention.

Belling the "cat": Wnt/β-catenin signaling and its significance in future cancer therapies

The WNT/β-catenin is among one of the most extensively studied cellular signaling pathways involved in the initiation and progression of several deadly cancers. It is now understood that the WNT/β-catenin signaling, during tumor progression operates in a very complex fashion beyond the earlier assumed simple WNT 'On' or 'Off' mode as it recruits numerous WNT ligands, receptors, transcriptional factors and also cross-talks with other signaling molecules including the noncanonical WNT regulators. WNT/β-catenin signaling molecules are often mutated in different cancers which makes them very challenging to inhibit and sometimes ranks them among the undruggable targets. Furthermore, due to the evolutionary conservation of this pathway, inhibiting WNT/β-catenin has caused significant toxicity in normal cells. These challenges are reflected in clinical trial data, where the use of WNT/β-catenin inhibitors as standalone treatments remains limited. In this review, we have highlighted the crucial functional associations of diverse WNT/β-catenin signaling regulators with cancer progression and the phenotypic switching of tumor cells. Next, we have shed light on the roles of WNT/β-catenin signaling in drug resistance, clonal evolution, tumor heterogeneity, and immune evasion. The present review also focuses on various classes of routine and novel WNT/β-catenin therapeutic regimes while addressing the challenges associated with targeting the regulators of this complex pathway. In the light of multiple case studies on WNT/β-catenin inhibitors, we also highlighted the challenges and opportunities for future clinical trial strategies involving these treatments. Additionally, we have proposed strategies for future WNT/β-catenin-based drug discovery trials, emphasizing the potential of combination therapies and AI/ML-driven prediction approaches. Overall, here we showcased the opportunities, possibilities, and potentialities of WNT/β-catenin signaling modulatory therapeutic regimes as promising precision cancer medicines for the future.

Taking the road less traveled - the therapeutic potential of CBP/β-catenin antagonists

AREAS COVERED

This perspective discusses the challenges of targeting the Wnt signaling cascade, the safety, efficacy, and therapeutic potential of specific CBP/β-catenin antagonists and a rationale for the pleiotropic effects of CBP/β-catenin antagonists beyond Wnt signaling.

EXPERT OPINION

CBP/β-catenin antagonists can correct lineage infidelity, enhance wound healing, both normal and aberrant (e.g. fibrosis) and force the differentiation and lineage commitment of stem cells and cancer stem cells by regulating enhancer and super-enhancer coactivator occupancy. Small molecule CBP/β-catenin antagonists rebalance the equilibrium between CBP/β-catenin versus p300/β-catenin dependent transcription and may be able to treat or prevent many diseases of aging, via maintenance of our somatic stem cell pool, and regulating mitochondrial function and metabolism involved in differentiation and immune cell function.