The ubiquitin–proteasome system is an essential regulator of several cellular pathways involving oncogenes. Deubiquitination negatively regulates target proteins or substrates linked to both hereditary and sporadic forms of cancer. The deubiquitinating enzyme ubiquitin-specific protease 14 (USP14) is associated with proteasomes where it trims the ubiquitin chain on the substrate. Here, we found that USP14 is highly expressed in patients with lung cancer. We also demonstrated that USP14 inhibitors (IU1-47 and siRNA-USP14) significantly decreased cell proliferation, migration, and invasion in lung cancer. Remarkably, we found that USP14 negatively regulates lung tumorigenesis not only through apoptosis but also through the autophagy pathway. Our findings suggest that USP14 plays a crucial role in lung tumorigenesis and that USP14 inhibitors are potent drugs in lung cancer treatment.

Combining standard surgical procedures with personalized chemotherapy and the continuous monitoring of cancer progression is necessary for effective NSCLC treatment. In this study, we developed liposomal nanoparticles as theranostic agents capable of simultaneous therapy for and imaging of target cancer cells. Copper-64 (⁶⁴Cu), with a clinically practical half-life (t_1/2 = 12.7 h) and decay properties, was selected as the radioisotope for molecular PET imaging. An anti-epidermal growth factor receptor (anti-EGFR) antibody was used to achieve target-specific delivery. Simultaneously, the chemotherapeutic agent doxorubicin (Dox) was encapsulated within the liposomes using a pH-gradient method. The conjugates of ⁶⁴Cu-labeled and anti-EGFR antibody-conjugated micelles were inserted into the doxorubicin-encapsulating liposomes via a post-insertion procedure (⁶⁴Cu-Dox-immunoliposomes). We evaluated the size and zeta-potential of the liposomes and analyzed target-specific cell binding and cytotoxicity in EGFR-positive cell lines. Then, we analyzed the specific therapeutic effect and PET imaging of the ⁶⁴Cu-Dox-immunoliposomes with the A549 xenograft mouse model. In vivo therapeutic experiments on the mouse models demonstrated that the doxorubicin-containing ⁶⁴Cu-immunoliposomes effectively inhibited tumor growth. Moreover, the ⁶⁴Cu-immunoliposomes provided superior in vivo PET images of the tumors compared to the untargeted liposomes. We suggest that nanoparticles will be the potential platform for cancer treatment as a widely applicable theranostic system.

Extracellular vesicles (EVs) demonstrate immense potential as naturally derived carriers of active therapeutics. To maximize their capacity, it is crucial to develop effective methods for manipulating cargo and ensuring scalability. To address this challenge, we propose that protein-free mRNA granule-like structures, named gene-encoded nanoparticle RNA for inducing superior EVs (GENRISE), can function as active translational sponge and as transient subcellular compartments. The overexpression of proteins in proximity to RNA assemblies stimulates parental cells to release excess exogenous proteins in induced superior EVs (iSEVs). The iSEV system enables the single-module–based enrichment of exogenous cargo in EVs with scalable manufacturing. By harnessing mass-produced iSEVs induced by GENRISEs, encoding an antigenic peptide, we have successfully demonstrated target-specific in vivo cancer immunotherapy. These findings suggest that the emerging iSEV platform shows considerable potential for biomedical applications by enabling the controlled production of cargo-specific EVs.

Background: Gastric cancer is one of the most prevalent malignancies worldwide and the fourth leading cause of cancer-related mortality. Protein ubiquitination and deubiquitination regulate protein stability as post-translational modifications, playing essential roles in tumorigenesis. Although UCHL1, a deubiquitinating enzyme (DUB), is implicated in the progression of several cancer types, its role in gastric cancer remains unclear. Methods: Kaplan–Meier analysis and gastric cancer patient tissues were used to assess UCHL1 expression. Cell viability assay, colony-forming assay, and transwell migration and invasion assay were performed to evaluate cell growth. Immunoprecipitation and Western blotting analyzed protein expression and interactions. Results: This study demonstrates that UCHL1 expression is markedly upregulated in gastric cancer tissues compared to normal tissues. Elevated UCHL1 expression is associated with poor patient prognosis, supporting its potential role as an oncogenic factor. Reduced UCHL1 expression suppressed cell proliferation, migration, and invasion in gastric cancer cell lines. As the underlying mechanism, we identified CIP2A, a known oncogenic regulator of c-Myc, as a downstream effector of UCHL1. UCHL1 knockdown reduced CIP2A protein levels via deubiquitination, attenuated c-Myc signaling, and decreased expression of key cell cycle regulators. Furthermore, UCHL1 knockdown significantly downregulated cyclin D1 expression, arresting the cell cycle in the G1 phase and inhibiting cell proliferation. Conclusions: Collectively, our findings reveal that UCHL1 promotes gastric cancer progression, highlighting it as a potential therapeutic target.

Background/Objectives: Gastric cancer is an aggressive malignancy with poor prognosis, and acquired resistance to 5-fluorouracil (5-FU) remains a major therapeutic challenge. BRCA1-associated protein-1 (BAP1), a deubiquitinating enzyme, has been implicated in tumorigenesis; however, its role in gastric cancer and 5-FU resistance remains unclear. This study investigated the functional and molecular roles of BAP1 in gastric cancer progression and chemoresistance. Methods: BAP1 expression and its association with patient prognosis were evaluated in gastric cancer tissues. The effects of BAP1 depletion on cancer cell proliferation, migration, invasion, and apoptosis were examined. The interaction between BAP1 and BIRC5 (Survivin) and the effects of BAP1-mediated deubiquitination on BIRC5 stability were investigated. The therapeutic effect of the BAP1 inhibitor iBAP-II was further assessed in 5-FU resistant gastric cancer cells. Results: BAP1 was significantly upregulated in gastric cancer tissues and associated with poor prognosis. BAP1 knockdown suppressed proliferation, migration, and invasion. Further analysis revealed that BAP1 interacted with and stabilized BIRC5 through deubiquitination, thereby suppressing apoptosis. BAP1 and BIRC5 were markedly upregulated in 5-FU resistant cells, whereas iBAP-II treatment enhanced 5-FU sensitivity and increased caspase-3 and PARP cleavage. Conclusions: BAP1 promotes gastric cancer progression and 5-FU resistance by stabilizing BIRC5. Targeting the BAP1–BIRC5 axis may represent a promising strategy for overcoming 5-FU resistance and improving therapeutic efficacy in gastric cancer.