BAP1-mediated MAFF deubiquitylation regulates tumor growth and is associated with adverse outcomes in colorectal cancer.

BACKGROUND: Despite improvements in colorectal cancer (CRC) treatment, the prognosis for advanced CRC patients remains poor. Disruption of protein stability is one of the important factors in cancer development and progression. In this study, we aim to identify and analyze novel dysregulated proteins in CRC, assessing their significance and the mechanisms. METHODS: Using quantitative proteomics, expression pattern analysis, and gain-of-function/loss-of-function experiments, we identify novel functional protein dysregulated by ubiquitin-proteasome axis in CRC. Prognostic significance was evaluated in a training cohort of 546 patients and externally validated in 794 patients. Mechanistic insights are gained through molecular biology experiments, deubiquitinating enzymes (DUBs) expression library screening, and RNA sequencing. RESULTS: MAFF protein emerged as the top novel candidate substrate regulated by ubiquitin-proteasome in CRC. MAFF protein was preferentially downregulated in CRC compared to adjacent normal tissues. More importantly, multicenter cohort study identified reduced MAFF protein expression as an independent predictor of overall and disease-free survival in CRC patients. The in vitro and vivo assays showed that MAFF overexpression inhibited CRC growth, while its knockdown had the opposite effect. Intriguingly, we found the abnormal expression of MAFF protein was predominantly regulated via ubiquitination of MAFF, with K48-ubiquitin being dominant. BAP1 as a nuclear deubiquitinating enzyme (DUB), bound to and deubiquitinated MAFF, thereby stabilizing it. Such stabilization upregulated DUSP5 expression, resulting in the inhibition of ERK phosphorylation. CONCLUSIONS: This study describes a novel BAP1-MAFF signaling axis which is crucial for CRC growth, potentially serving as a therapeutic target and a promising prognostic biomarker for CRC.

Subtype discrimination of acute myeloid leukemia based on plasma SERS technique.

Acute myeloid leukemia (AML) is a common hematologic malignancy. To this day, diagnose of AML and its genetic mutation still rely on invasive and time-consuming methods. In this study, 222 plasma samples were collected to discuss the performance of surface-enhanced Raman spectroscopy (SERS) to discriminate AML subtype acute promyelocytic leukemia and acute monocytic leukemia based on plasma. The Ag nanoparticles-based SERS technique was used to explore the biochemical differences among different AML subtypes. With the help of powerful supervised and unsupervised algorithms, the performance using the whole spectra and band intensities was confirmed to identify different subtypes of AML. The results demonstrated the intensities of several bands and band-intensity ratios were significantly different between groups, thus related to the discrimination of several AML subtypes and control. Combining indexes of band-intensity ratios, the result of multi-indexes ROC has excellent performance in differentiating AML patient with healthy control. Our work demonstrated the great potential of SERS technique as a rapid and micro detection method in clinical laboratory field, it's a new and powerful tool for analyzing human blood plasma.

miR-200b-3p mitigates oxaliplatin resistance via targeting TUBB3 in colorectal cancer.

BACKGROUND: Numerous abnormally expressed miRs have been reported involved in oxaliplatin (L-OHP) resistance of colorectal cancer (CRC). The present study aimed to investigate whether miR-200b-3p could regulate L-OHP resistance via targeting TUBB3 in CRC cells. METHODS: L-OHP resistant HT29 and HCT116 cells were exposed to escalating concentrations of L-OHP up to 30 µm. The effect of miR-200b-3p on L-OHP resistant CRC cells was then evaluated using the cell counting kit-8 (CCK-8) assay. CRC cell apoptosis was detected using Annexin V-FITC/PI double staining. Bioinformatics algorithms and luciferase reporter assays were also performed to investigate whether TUBB3 was a direct target of miR-200b-3p. RESULTS: miR-200b-3p declined in L-OHP resistant CRC tissues and cell lines, and the overexpression of miR-200b-3p elevated the L-OHP sensitivity in L-OHP resistant HT29 and HCT116 cells. In addition, we determined the potential mechanisms underlying miR-200b-3p-mediated reversal of L-OHP resistance by mediating its downstream target TUBB3, and the overexpression of miR-200b-3p could induce migration and growth inhibition and apoptosis in L-OHP resistant HT29 and HCT116 cells by silencing ßIII-tubulin protein expression. However, the overexpression of TUBB3 reversed miR-200b-3p mimic-induced migration, as well as growth inhibition and apoptosis, in L-OHP resistant CRC cells. CONCLUSIONS: miR-200b-3p improved L-OHP resistance and induced growth inhibition and cell apoptosis in L-OHP resistant CRC cells, and the underlying mechanism was mediated, at least partially, through the suppression of ßIII-tubulin protein expression.

(-)-4-O-(4-O-ß-D-glucopyranosylcaffeoyl) Quinic Acid Inhibits the Function of Myeloid-Derived Suppressor Cells to Enhance the Efficacy of Anti-PD1 against Colon Cancer.

PURPOSE: Immunotherapy in the clinic has demonstrated its potential to control cancer through disinhibiting the immune system, especially for immune checkpoint inhibitors such as anti-programmed cell death protein 1/anti-programmed death-ligand 1 (anti-PD1/anti-PD-L1). However, although these new immunotherapies have resulted in durable clinical responses in various cancers, multiple mechanisms of immune resistance and suppression exist in tumors. One significant barrier to efficacy of anti-PD1 against colon cancer may be the recruitment of myeloid-derived suppressor cells (MDSCs) into the tumor microenvironment. Here we demonstrated functional inhibition of G-MDSC with (-)-4-O-(4-O-ß-D-glucopyranosylcaffeoyl) quinic acid (QA), an inhibitor of PI3Kδ/γ, reshaped the tumor immune microenvironment and promoted cytotoxic T cell-mediated tumor regression, resultantly enhancing responses to anti-PD1 treatment in colon tumor model. METHODS: A syngeneic colon tumor mouse model was used to study the effects of QA on tumor immune microenvironment and its potential synergistic effects with anti-PD1 blockade. RESULTS: QA treatment inhibited G-MDSC function in the tumor tissue. Additionally, combination treatment induced CD8+ T lymphocyte-dependent tumor growth delay and prolonged survival time in colon cancer. CONCLUSIONS: Our results offered opportunities for new combination strategies using a selective small molecule PI3Kδ/γ inhibitor, to suppress MDSCs to enhance responses to immune checkpoint blockade in colon cancer.

Upregulation of microRNA-370 promotes cell apoptosis and inhibits proliferation by targeting PTEN in human gastric cancer.

Growing evidence suggests that microRNA plays an essential role in the development and metastasis of many tumors, including gastric cancer. Aberrant miR­370 expression has been indicated in tumor growth, but the mechanism of miR­370 inhibits both the proliferation and metastatic ability for gastric cancer remains unclear. Accumulating evidence reported that PTEN signaling pathway plays an important role in the cellular processes, such as apoptosis, cell growth and proliferation. The goal of this study was to identify whether miR­370 could inhibit the growth, migration, invasion, proliferation and metastasis of gastric cancer through targeting PTEN. Real-time PCR (RT-PCR) was used to quantify miR-370 expression in vitro experiments. The biological functions of miR­370 were determined via cell proliferation. Our study indicated that miR­370 targeted PTEN leading to activation of apoptosis signaling and the cell proliferation of cervical cancer cells, ameliorating gastric cancer growth and progression. In addition, the combination of miR­370 and PTEN inactivated AKT, MDM2 and mTOR while stimulated caspase-3, p53 and GSK3ß expression, promoting apoptosis and suppressing proliferation of gastric cancer cells. Therefore, our study revealed the mechanistic links between miR­370 and PTEN in the pathogenesis of gastric cancer through modulation of cell apoptosis and proliferation. Additionally, targeting miR­370 could serve as a novel strategy for future gastric cancer therapy clinically.

Peptic Ulcer Disease in Healthcare Workers: A Nationwide Population-Based Cohort Study.

Health care workers (HCWs) in Taiwan have heavy, stressful workloads, are on-call, and have rotating nightshifts, all of which might contribute to peptic ulcer disease (PUD). We wanted to evaluate the PUD risk in HCWs, which is not clear. Using Taiwan's National Health Insurance Research Database, we identified 50,226 physicians, 122,357 nurses, 20,677 pharmacists, and 25,059 other HCWs (dieticians, technicians, rehabilitation therapists, and social workers) as the study cohort, and randomly selected an identical number of non-HCW patients (i.e., general population) as the comparison cohort. Conditional logistical regression analysis was used to compare the PUD risk between them. Subgroup analysis for physician specialties was also done. Nurses and other HCWs had a significantly higher PUD risk than did the general population (odds ratio [OR]: 1.477; 95% confidence interval [CI]: 1.433-1.521 and OR: 1.328; 95% CI: 1.245-1.418, respectively); pharmacists had a lower risk (OR: 0.884; 95% CI: 0.828-0.945); physicians had a nonsignificantly different risk (OR: 1.029; 95% CI: 0.987-1.072). In the physician specialty subgroup analysis, internal medicine, surgery, Ob/Gyn, and family medicine specialists had a higher PUD risk than other physicians (OR: 1.579; 95% CI: 1.441-1.731, OR: 1.734; 95% CI: 1.565-1.922, OR: 1.336; 95% CI: 1.151-1.550, and OR: 1.615; 95% CI: 1.425-1.831, respectively). In contrast, emergency physicians had a lower risk (OR: 0.544; 95% CI: 0.359-0.822). Heavy workloads, long working hours, workplace stress, rotating nightshifts, and coping skills may explain our epidemiological findings of higher risks for PUD in some HCWs, which might help us improve our health policies for HCWs.