Protein ubiquitination is a reversible post-translational modification regulated by ubiquitin-conjugating and deubiquitinating enzymes (DUBs). Ubiquitin-specific protease 7 (USP7), a well-characterized DUB, plays multifaceted roles in various cellular processes, making it a promising therapeutic target. The plasticity of its catalytic domain and unique allosteric regulation by substrates or external or intramolecular factors facilitate the identification of highly selective USP7 inhibitors. These inhibitors can engage distinct ubiquitin-binding sites through covalent or non-covalent mechanisms. Despite its therapeutic promise, no USP7 inhibitors have entered clinical trials, underscoring the urgent need for novel therapeutics. Here we provide a crystallographic and functional landscape of USP7's multilayer regulation and analyze the structure-activity relationship of inhibitors by chemotypes. Additionally, we explore USP7's roles in diseases and discuss the challenges in USP7-targeted drug discovery and future directions for therapeutic development. This Perspective aims to provide a systematic overview of USP7, from its regulatory mechanisms to its therapeutic potential.

Ubiquitin-specific proteases (USPs) are a subset of deubiquitinating enzymes (DUBs) that have crucial roles in regulating key signaling pathways, DNA repair mechanisms, and immune responses by modulating the interactions and stability of proteins, including oncogenes and tumor suppressors in many cancers, such as colorectal cancer (CRC). USPs present an attractive reservoir of drug targets that could potentially overcome the shortcomings of conventional pathway-specific cancer therapies. This review explores the roles of USPs in CRC, addresses the challenges in discovering and developing USP inhibitors, highlights recent advancements in drug development, and discusses the potential of targeted protein degraders and stabilizers including proteolysis-targeting chimeras (PROTACs), molecular glues, and DUB-targeting chimeras (DUBTACs) as strategies for drugging USPs.

Deubiquitinases (DUBs) are essential for the maintenance of protein homeostasis and assembly of proteins into functional complexes. Despite growing interest in DUBs biological functions, the roles of DUBs in regulating intestinal stem cells (ISCs) and gut homeostasis remain largely unknown. Here, we perform an in vivo RNAi screen through induced knock-down of DUBs expression in adult midgut ISCs and enteroblasts (EBs) to identify DUB regulators of intestinal homeostasis in Drosophila. We screen 43 DUBs and identify 8 DUBs that are required for ISCs homeostasis. Knocking-down of usp1, CG7857, usp5, rpn8, usp10 and csn5 decreases the number of ISCs/EBs, while knocking-down of CG4968 and usp8 increases the number of ISCs/EBs. Moreover, knock-down of usp1, CG4968, CG7857, or rpn8 in ISCs/EBs disrupts the intestinal barrier integrity and shortens the lifespan, indicating the requirement of these DUBs for the maintenance of gut homeostasis. Furthermore, we provide evidences that USP1 mediates ISC lineage differentiation via modulating the Notch signaling activity. Our study identifies, for the first time, the deubiquitinases required for the maintenance of intestinal homeostasis in Drosophila, and provide new insights into the functional links between the DUBs and intestinal homeostasis.

Tumor recurrence is a mechanism triggered in sparse populations of cancer cells that usually remain in a quiescent state after strict stress and/or therapeutic factors, which is affected by a variety of autocrine and microenvironmental cues. Despite thorough investigations, the biology of dormant and/or cancer stem cells is still not fully elucidated, as for the mechanisms of their reawakening, while only the major molecular patterns driving the relapse process have been identified to date. These molecular patterns profoundly interfere with the elements of cellular proteostasis systems that support the efficiency of the recurrence process. As a major proteostasis machinery, we review the role of the ubiquitin-proteasome system (UPS) in tumor cell dormancy and reawakening, devoting particular attention to the functions of its components, E3 ligases, deubiquitinating enzymes and proteasomes in cancer recurrence. We demonstrate how UPS components functionally or mechanistically interact with the pivotal proteins implicated in the recurrence program and reveal that modulators of the UPS hold promise to become an efficient adjuvant therapy for eradicating refractory tumor cells to impede tumor relapse.

The transcription factor FOXL2 is required in ovarian somatic cells for female fertility. Differential timing of Foxl2 deletion, in embryonic versus adult mouse ovary, leads to distinctive outcomes, suggesting different roles across development. Here, we comprehensively investigated FOXL2's role through a multi-omics approach to characterize gene expression dynamics and chromatin accessibility changes, coupled with genome-wide identification of FOXL2 targets and on-chromatin interacting partners in somatic cells across ovarian development. We found that FOXL2 regulates more targets postnatally, through interaction with factors regulating primordial follicle formation and steroidogenesis. Deletion of one interactor, ubiquitin-specific protease 7 (Usp7), results in impairment of somatic cell differentiation, germ cell nest breakdown, and ovarian development, leading to sterility. Our datasets constitute a comprehensive resource for exploration of the molecular mechanisms of ovarian development and causes of female infertility.

Colorectal cancer (CRC) is the third most frequent and the second most fatal cancer. The search for more effective drugs to treat this disease is ongoing. A better understanding of the mechanisms of CRC development and progression may reveal new therapeutic strategies. Ubiquitin-specific peptidases (USPs), the largest group of the deubiquitinase protein family, have long been implicated in various cancers. There have been numerous studies on the role of USPs in CRC; however, a comprehensive view of this role is lacking.

To provide a systematic review of the studies investigating the roles and functions of USPs in CRC.

We systematically queried the MEDLINE (via PubMed), Scopus, and Web of Science databases.

Our study highlights the pivotal role of various USPs in several processes implicated in CRC: Regulation of the cell cycle, apoptosis, cancer stemness, epithelial-mesenchymal transition, metastasis, DNA repair, and drug resistance. The findings of this study suggest that USPs have great potential as drug targets and noninvasive biomarkers in CRC. The dysregulation of USPs in CRC contributes to drug resistance through multiple mechanisms.

Targeting specific USPs involved in drug resistance pathways could provide a novel therapeutic strategy for overcoming resistance to current treatment regimens in CRC.

Colorectal cancer (CRC) is the fifth most fatal cancer with a low probability of surgery and limited treatment options, especially in metastatic CRC. In this study, we investigated whether a mouse model of metastatic CRC mimicked tumor progression and evaluated the effect of 5-fluorouracil (5-FU) treatment.

The CT26 mouse derived CRC cancer cell line was inoculated into mice, and the tumor bearing mice were divided into two groups: the experimental group and the control group. Micro-computed tomography (CT) and in vivo fluorescence were used to monitor the progression of metastatic CRC. A lung metastasis mouse model was employed to determine the effects of 5-FU on metastasis.

Bioluminescence imaging (BLI) and computed tomography (CT), as non-invasive methods, can continuously monitor the growth of tumors in vivo. Thus, imaging techniques can be used to qualitatively and quantitatively evaluate tumor growth indicators. 5-FU injected intravenously reduced the viability of metastatic CRC cells and resulted in prolonged survival compared to the control group. Moreover, the 5-FU-treated group had significantly reduced fluorescence of the CT26 cells in the lung. The results observed by BLI and CT are consistent with the tissue morphology and structure presented in pathological examination.

In summary, a successful mouse model of CRC metastasis for clinical application has been established.

Transforming growth factor β (TGFβ) pathway is a master regulator of cell proliferation, differentiation, and death. Deregulation of TGFβ signalling is well established in several human diseases including autoimmune disorders and cancer. Thus, understanding molecular pathways governing TGFβ signalling may help better understand the underlying causes of some of those conditions. Here, we show that a HECT domain E3 ubiquitin ligase TRIP12 controls TGFβ signalling in multiple models. Interestingly, TRIP12 control of TGFβ signalling is completely independent of its E3 ubiquitin ligase activity. Instead, TRIP12 recruits SMURF2 to SMAD4, which is most likely responsible for inhibitory monoubiquitination of SMAD4, since SMAD4 monoubiquitination and its interaction with SMURF2 were dramatically downregulated in TRIP12-/- cells. Additionally, genetic inhibition of TRIP12 in human and murine cells leads to robust activation of TGFβ signalling which was rescued by re-introducing wildtype TRIP12 or a catalytically inactive C1959A mutant. Importantly, TRIP12 control of TGFβ signalling is evolutionary conserved. Indeed, genetic inhibition of Drosophila TRIP12 orthologue, ctrip, in gut leads to a reduced number of intestinal stem cells which was compensated by the increase in differentiated enteroendocrine cells. These effects were completely normalised in Drosophila strain where ctrip was co-inhibited together with Drosophila SMAD4 orthologue, Medea. Similarly, in murine 3D intestinal organoids, CRISPR/Cas9 mediated genetic targeting of Trip12 enhances TGFβ mediated proliferation arrest and cell death. Finally, CRISPR/Cas9 mediated genetic targeting of TRIP12 in MDA-MB-231 breast cancer cells enhances the TGFβ induced migratory capacity of these cells which was rescued to the wildtype level by re-introducing wildtype TRIP12. Our work establishes TRIP12 as an evolutionary conserved modulator of TGFβ signalling in health and disease.

Due to the heterogeneity of colon cancer, surgery, chemotherapy, and radiation are ineffective in all cases. The genomic profile and biomarkers associated with the process are considered in personalized medicine, along with the patient's personal history. It is based on the response of the targeted therapies to specific genetic variations. The patient's genetic transcriptomic and epigenetic features are evaluated, and the best therapeutic approach and diagnostic testing are identified through personalized medicine. This review aims to summarize all the necessary, updated information on colon cancer related to personalized medicine. Personalized medicine is gaining prominence as generalized treatments are finding it challenging to contain colon cancer cases which currently rank fourth among global cancer incidence while being the fifth largest in total death cases worldwide. In personalized therapy, patients are grouped into specific categories, and the best therapeutic approach is chosen based on evaluating their molecular features. Various personalized strategies are currently being explored in the treatment of colon cancer involving immunotherapy, phytochemicals, and other biomarker-specific targeted therapies. However, significant challenges must be overcome to integrate personalized medicine into healthcare systems completely. We look at the various signaling pathways and genetic and epigenetic alterations associated with colon cancer to understand and identify biomarkers useful in targeted therapy. The current personalized therapies available in colon cancer treatment and the strategies being explored to improve the existing methods are discussed. This review highlights the advantages and limitations of personalized medicine in colon cancer therapy. The current scenario of personalized medicine in developed countries and the challenges faced in middle- and low-income countries are also summarized. Finally, we discuss the future perspectives of personalized medicine in colon cancer and how it could be integrated into the healthcare systems.