PUM1 is upregulated by DNA methylation to suppress antitumor immunity and results in poor prognosis in pancreatic cancer

Pumilio RNA binding family member 1 deficiency activates anti-tumor immunity in hepatocellular carcinoma via restraining M2 macrophage polarization

Pumilio RNA-binding family member 1 (PUM1) has been implicated in both the progression of colorectal cancer and the regulation of inflammation. The role of PUM1 in the polarization of tumor-associated macrophages (TAMs) into the M2 phenotype has not yet been reported in hepatocellular carcinoma. Using the PUM1-knockout mice model, flow cytometry, and IHC, we validated the role of PUM1 in hepatocellular carcinoma (HCC) TAMs. One-way analysis of variance (ANOVA) or student's t-tests was used to compare the experimental groups. We found that PUM1 inhibited anti-tumor immunity in HCC through TAM-mediated inhibition of CD8+ T cells. We also showed that PUM1 promotes the transformation of TAMs into pro-tumorigenic M2-like phenotypes by activating cAMP signaling pathway. This study emphasized the potential of PUM1 as a target for immunotherapy in HCC through TAMs. The present study revealed the molecular mechanism underlying the pro-tumor role of PUM1 in HCC.

Exosome-mediated circGMPS facilitates the development of gastric cancer cells through miR-144-3p/PUM1

In recent years, gastric cancer (GC) is still one of the major public health burdens in the world. It is reported that exosome circular RNA (circRNA) is involved in the GC progression. However, the function and potential mechanism of circGMPS in GC remains unclear and needs further exploration. In this study, we isolated and identified exosomes from serum by TEM, NTA analysis and Western blot. RNA expression was evaluated by qRT-PCR. Western blot was employed to examine protein expression. Cell proliferation was measured using CCK-8. Transwell assay was adopted to analyze cell migration and invasion. The relationship between genes was explored through bioinformatics analysis, dual-luciferase reporter gene assay and spearman correlation coefficient. We found that circGMPS was elevated in GC exosomes, tissues and cells. Poor prognosis of GC patients was related to high circGMPS expression. Both exosome co-culture with cells and insertion of circGMPS clearly promoted cell progression. Mechanically, circGMPS sponged miR-144-3p to regulate PUM1. Inhibition of PUM1 or miR-144-3p overexpression inhibited the malignant GC cell progression. Our data confirmed that exosome-derived circGMPS boosted malignant progression by miR-144-3p/PUM1 axis in GC cells, providing strong evidences for circGMPS as a clinical biomarker of GC treatment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10616-023-00597-9.

Promoter Methylation-Regulated Differentially Expressed Genes in Breast Cancer

Background

Breast cancer is one of the most common malignancies among women. Recent studies revealed that differentially methylated regions (DMRs) are implicated in regulating gene expression. The goal of this research was to determine which genes and pathways are dysregulated in breast cancer when their promoters are methylated in an abnormal way, leading to differential expression. Whole-genome bisulfite sequencing was applied to analyze DMRs for eight peripheral blood samples collected from five Saudi females diagnosed with stages I and II of breast cancer aligned with three normal females. Three of those patients and three normal samples were used to determine differentially expressed genes (DEG) using Illumina platform NovaSeq PE150.

Results

Based on ontology (GO) and KEGG pathways, the analysis indicated that DMGs and DEG are closely related to associated processes, such as ubiquitin-protein transferase activity, ubiquitin-mediated proteolysis, and oxidative phosphorylation. The findings indicated a potentially significant association between global hypomethylation and breast cancer in Saudi patients. Our results revealed 81 differentially promoter-methylated and expressed genes. The most significant differentially methylated and expressed genes found in gene ontology (GO) are pumilio RNA binding family member 1 (PUM1) and zinc finger AN1-type containing 2B (ZFAND2B) also known as (AIRAPL).

Conclusion

The essential outcomes of this study suggested that aberrant hypermethylation at crucial genes that have significant parts in the molecular pathways of breast cancer could be used as a potential prognostic biomarker for breast cancer.

Identification of a New m6A Regulator-Related Methylation Signature for Predicting the Prognosis and Immune Microenvironment of Patients with Pancreatic Cancer

Pancreatic cancer (PC) is a malignant tumor of the digestive system that has a bad prognosis. N6-methyladenosine (m6A) is involved in a wide variety of biological activities due to the fact that it is the most common form of mRNA modification in mammals. Numerous research has accumulated evidence suggesting that a malfunction in the regulation of m6A RNA modification is associated with various illnesses, including cancers. However, its implications in PC remain poorly characterized. The methylation data, level 3 RNA sequencing data, and clinical information of PC patients were all retrieved from the TCGA datasets. Genes associated with m6A RNA methylation were compiled from the existing body of research and made available for download from the m6Avar database. The LASSO Cox regression method was used to construct a 4-gene methylation signature, which was then used to classify all PC patients included in the TCGA dataset into either a low- or high-risk group. In this study, based on the set criteria of |cor| > 0.4 and p value < 0.05. A total of 3507 gene methylation were identified to be regulated by m6A regulators. Based on the univariate Cox regression analysis and identified 3507 gene methylation, 858 gene methylation was significantly associated with the patient's prognosis. The multivariate Cox regression analysis identified four gene methylation (PCSK6, HSP90AA1, TPM3, and TTLL6) to construct a prognosis model. Survival assays indicated that the patients in the high-risk group tend to have a worse prognosis. ROC curves showed that our prognosis signature had a good prediction ability on patient survival. Immune assays suggested a different immune infiltration pattern in patients with high- and low-risk scores. Moreover, we found that two immune-related genes, CTLA4 and TIGIT, were downregulated in high-risk patients. We generated a unique methylation signature that is related to m6A regulators and is capable of accurately predicting the prognosis for patients with PC. The findings might prove useful for therapeutic customization and the process of making medical decisions.

Up-regulation of PUM1 by miR-218-5p promotes colorectal tumor-initiating cell properties and tumorigenesis by regulating the PI3K/AKT axis

Background

Colorectal cancer (CRC) is the third most common cancer and the fourth most common cause of cancer-related death worldwide. Advanced stage CRC, during the recent past, had a dismal prognosis and only a few available treatments. Pumilio homologous protein 1 (PUM1) is reportedly aberrant in human malignancies, including CRC. However, the role of PUM1 in the regulation of tumor-initiating cells (T-ICs) remains unknown.

Methods

The levels of messenger RNAs (mRNAs) were determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and immunoblot analyses. Statistical analyses were performed to determine the associations between the levels of PUM1 and tumor features and patient outcomes. Whether PUM1 is a downstream target of miR-218-5p was verified by bioinformatics target gene prediction and qRT-PCR.

Results

Herein, it was found that T-ICs, chemoresistance, and recurrent CRC samples all manifest increased PUM1 expression. Functional investigations have shown that PUM1 increased the self-renewal, tumorigenicity, malignant proliferation, and chemoresistance of colorectal cells. PUM1 activates the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) signaling pathway biochemically. Furthermore, it was discovered that miR-218-5p specifically targets T-ICs' PUM1 3'-untranslated region (3'-UTR). More importantly, the PUM1/PI3K/AKT axis regulates CRC cells' responses to treatment with cetuximab, and PUM1 overexpression increased cetuximab resistance. More evidence points to the possibility that low PUM1 may predict cetuximab benefits in CRC patients after analysis of the patient cohort, patient-derived tumor organoids, and patient-derived xenografts (PDXs).

Conclusions

Taken together, the result of this work points to the critical function of the miR-218-5p/PUM1/PI3K/AKT regulatory circuit in regulating T-ICs characteristics and thus suggests possible therapeutic targets for CRC.

The protective effects of Esculentoside A through AMPK in the triple transgenic mouse model of Alzheimer's disease

BACKGROUND

Neurofibrillary tangles comprising hyperphosphorylated tau are vital factors associated with the pathogenesis of Alzheimer's disease (AD). The elimination or reduction of hyperphosphorylated and abnormally aggregated tau is a valuable measure in AD therapy. Esculentoside A (EsA), isolated from Phytolacca esculenta, exhibits pharmacotherapeutic efficacy in mice with amyloid beta-induced AD. However, whether EsA affects tau pathology and its specific mechanism of action in AD mice remains unclear.

PURPOSE

To investigate the roles and mechanisms of EsA in cognitive decline and tau pathology in a triple transgenic AD (3 × Tg-AD) mouse model.

METHODS

EsA (5 and 10 mg/kg) was administered via intraperitoneal injection to 8-month-old AD mice for eight consecutive weeks. Y-maze and novel object recognition tasks were used to evaluate the cognitive abilities of mice. Potential signaling pathways and targets in EsA-treated AD mice were assessed using quantitative proteomic analysis. The NFT levels and hippocampal synapse numbers were investigated using Gallyas-Braak silver staining and transmission electron microscopy, respectively. Western blotting and immunofluorescence assays were used to measure the expression of tau-associated proteins.

RESULTS

EsA administration attenuated memory and recognition deficits and synaptic damage in AD mice. Isobaric tags for relative and absolute quantitation proteomic analysis of the mouse hippocampus revealed that EsA modulated the expression of some critical proteins, including brain-specific angiogenesis inhibitor 3, galectin-1, and Ras-related protein 24, whose biological roles are relevant to synaptic function and autophagy. Further research revealed that EsA upregulated AKT/GSK3β activity, in turn, inhibited tau hyperphosphorylation and promoted autophagy to clear abnormally phosphorylated tau. In hippocampus-derived primary neurons, inhibiting AMP-activated protein kinase (AMPK) activity through dorsomorphin could eliminate the effect of EsA, as revealed by increased tau hyperphosphorylation, downregulated activity AKT/GSK3β, and blocked autophagy.

CONCLUSIONS

To our knowledge, this study is the first to demonstrate that EsA attenuates cognitive decline by targeting the pathways of both tau hyperphosphorylation and autophagic clearance in an AMPK-dependent manner and it shows a high reference value in AD pharmacotherapy research.

Elevated BTG2 improves the radiosensitivity of non-small cell lung cancer (NSCLC) through apoptosis

BACKGROUND

To identify radio-responsive genes and explore the biological function of encoded proteins in non-small cell lung cancer (NSCLC).

METHODS

Radio-responsive genes in irradiated H460 cells were screened from microarray data deposited in the Gene Expression Omnibus (GEO) database. A quantitative real time polymerase chain reaction assay was used to detect the expression of candidate radio-responsive genes in irradiated cells. CCK-8 assay, EDU assay, clone formation assay, immunofluorescence and flow cytometry were conducted to evaluate the biological function of B cell translocation gene 2 (BTG2) in NSCLC.

RESULTS

Bioinformatic analysis using GES20549 showed that BTG2 was a radio-responsive gene in irradiated H460 cells. The mRNA expression level of BTG2 was lower in H460 cells compared with that in BEAS-2B normal lung epithelial cells. BTG2 expression was elevated upon IR exposure, in a dose-dependent but not a time-dependent manner. CCK-8 and EDU assays revealed that BTG2 overexpression inhibited the growth rate of irradiated cells. Clone formation showed that elevated BTG2 promoted DNA damage of irradiated H460 cells. The number of γ-H2AX foci induced by DNA damage was also markedly increased upon BTG2 overexpression. Flow cytometry showed that BTG2 increased IR-induced cell apoptosis.

CONCLUSIONS

BTG2 may be a novel radio-responsive factor and a promising therapeutic target for radiotherapy of NSCLC.