Low tumour PPM1H indicates poor prognosis in colorectal cancer via activation of cancer-associated fibroblasts

Measuring cancer driving force of chromosomal aberrations through multi-layer Boolean implication networks

Multi-layer Complex networks are commonly used for modeling and analysing biological entities. This paper presents the advantage of using COMBO (Combining Multi Bio Omics) to suggest a new role of the chromosomal aberration as a cancer driver factor. Exploiting the heterogeneous multi-layer networks, COMBO integrates gene expression and DNA-methylation data in order to identify complex bilateral relationships between transcriptome and epigenome. We evaluated the multi-layer networks generated by COMBO on different TCGA cancer datasets (COAD, BLCA, BRCA, CESC, STAD) focusing on the effect of a specific chromosomal numerical aberration, broad gain in chromosome 20, on different cancer histotypes. In addition, the effect of chromosome 8q amplification was tested in the same TCGA cancer dataset. The results demonstrate the ability of COMBO to identify the chromosome 20 amplification cancer driver force in the different TCGA Pan Cancer project datasets.

Functional regulation of the protein phosphatase PPM1M by phosphorylation at multiple sites with Ser/Thr-Pro motifs

The imbalance in the phosphorylation and the dephosphorylation of proteins leads to various diseases. Therefore, in vivo, the functions of protein kinases and protein phosphatases are strictly regulated. Mg2+/Mn2+-dependent protein phosphatase PPM1M has been implicated in immunity and cancer; however, the regulation mechanism remains unknown. In this study, we show that PPM1M is regulated in different ways by multiple phosphorylation. PPM1M has four Ser/Thr-Pro motifs (Ser27, Ser43, Ser60, and Thr254) that are recognized by proline-directed kinases, and Ser60 was found to be phosphorylated by cyclin-dependent kinase 5 (CDK5) in the cell. The phospho-mimetic mutation of Ser27 and Ser43 in the N-terminal domain suppresses the nuclear localization of PPM1M and promotes its accumulation in the cytoplasm. The phospho-mimetic mutation of Ser60 decreases PPM1M activity; conversely, the phospho-mimetic mutation of Thr254 increases PPM1M activity. These results suggest that the subcellular localization and phosphatase activity of PPM1M are regulated by protein kinases, including CDK5, via phosphorylation at multiple sites. Thus, PPM1M is differentially regulated by proline-directed kinases, including CDK5.

Association between immune-related hub genes CD36, CXCL13, FGFR4, GABBR1, LAMP3, MMP12, and PPM1H and colorectal cancer prognosis

The present study aims to identify immune-related prognostic genes in colorectal cancer (CRC), and to explore potential mechanisms through which these genes regulate CRC progression. We first constructed a prognostic risk model based on seven gene signatures [cluster of differentiation-36 (CD36), chemokine (C-X-C-motif) ligand 13 (CXCL13), fibroblast growth factor receptor 4 (FGFR4), gamma-amino-butyric acid type B receptor 1 (GABBR1), lysosome-associated membrane glycoprotein 3 (LAMP3), recombinant matrix metalloproteinase 12 (MMP12), and protein phosphatase 1H (PPM1H)] using integrated bioinformatic analyses. FGFR4, GABBR1, and LAMP3 were highly expressed in CRC cell lines (in comparison with a normal colonic epithelial cell line), while CD36, CXCL13, MMP12, and PPM1H were weakly expressed. These in vitro expression results were largely consistent with our bioinformatic analysis. A prognostic model was generated to identify a high-risk group with worse survival outcome based on Kaplan-Meier analysis. Our prognostic model showed superior accuracy in both the training and test cohorts. In addition, we found that the low-risk subgroup exhibited greater infiltration by M1 macrophages, CD8+ T cells, CD4+ T cells, and activated NK cells. In conclusion, our findings provide evidence that seven immune-related hub genes can be considered as gene signatures to predict CRC prognosis and to differentiate CRC patient benefit, ultimately serving as a guide for individualized immunotherapy.

Colon cancer transcriptome

Over the last four decades, methodological innovations have continuously changed transcriptome profiling. It is now feasible to sequence and quantify the transcriptional outputs of individual cells or thousands of samples using RNA sequencing (RNA-seq). These transcriptomes serve as a connection between cellular behaviors and their underlying molecular mechanisms, such as mutations. This relationship, in the context of cancer, provides a chance to unravel tumor complexity and heterogeneity and uncover novel biomarkers or treatment options. Since colon cancer is one of the most frequent malignancies, its prognosis and diagnosis seem to be critical. The transcriptome technology is developing for an earlier and more accurate diagnosis of cancer which can provide better protectivity and prognostic utility to medical teams and patients. A transcriptome is a whole set of expressed coding and non-coding RNAs in an individual or cell population. The cancer transcriptome includes RNA-based changes. The combined genome and transcriptome of a patient may provide a comprehensive picture of their cancer, and this information is beginning to affect treatment decision-making in real-time. A full assessment of the transcriptome of colon (colorectal) cancer has been assessed in this review paper based on risk factors such as age, obesity, gender, alcohol use, race, and also different stages of cancer, as well as non-coding RNAs like circRNAs, miRNAs, lncRNAs, and siRNAs. Similarly, they have been examined independently in the transcriptome study of colon cancer.

Identification of Long Noncoding RNAs Associated With the Clinicopathological Features of Papillary Thyroid Carcinoma Complicated With Hashimoto’s Thyroiditis

Long noncoding RNAs (lncRNAs) play a significant role in cancer biology. This study aimed to determine the roles of lncRNAs in establishing the differences in clinical features between patients with papillary thyroid carcinoma (PTC) without Hashimoto’s thyroiditis (HT) and patients with PTC and HT. In the present study, we detected the differentially expressed lncRNAs between tumor tissues of patients with PTC with or without HT through lncRNA microarrays. The data were verified and analyzed through qRT-PCR, cell viability, cell cycle and bioinformatics analyses. We found that 1031 lncRNAs and 1338 mRNAs were abnormally expressed in 5 tissue samples of PTC complicated with HT [PTC/HT (+)] compared with 5 samples of PTC without HT [PTC/HT (-)]. Gene Ontology and pathway analyses of the mRNAs suggested that several biological processes and pathways, particularly immune system processes, were induced in the PTC/HT (+) tissues. Twenty lncRNAs were verified in 31 PTC/HT (+) and 64 PTC/HT (-) specimens by qRT-PCR, and the results were consistent with the microarray data. Specifically, ENST00000452578, a downregulated lncRNA in PTC/HT(+), was negatively correlated with the tumor size. Cell viability assays revealed that ENST00000452578 could inhibit cell proliferation. Our results indicate that lncRNAs and mRNAs play an important role in establishing the different clinical characteristics between patients with PTC/HT(+) and patients with PTC/HT(-), and might provide new insights from the perspective of RNA for obtaining a further understanding of the clinical features related to PTC with HT.

SMARCD3 is a potential prognostic marker and therapeutic target in CAFs

OBJECTIVE

Screening for novel prognostic biomarkers and potential therapeutic targets from colorectal cancer microenvironment.

RESULTS

372 genes were overexpressed in colorectal cancer microenvironment, five of which that had the most prognostic powers were enriched in Epithelial-Mesenchymal Transition and cell cycle pathways. For the first time, we showed that SMARCD3 was mainly expressed in CAFs and could be a novel prognostic marker and potential therapeutic target. Function analyses indicated that MSARCD3 might promote CAFs activation and colorectal cancer metastasis through SMARCD3-WNT5A/TGF-β-MAPK14-SMARCD3 positive feedback loop. Signaling map of SMARCD3 was constructed and several potential drugs that could regulate SMARCD3 were also presented.

CONCLUSIONS

SMARCD3 is a novel prognostic biomarker and potential therapeutic target of colorectal cancer, which may promote cancer metastasis through activation of CAFs.

METHODS

Colorectal cancer microenvironment related genes were screened based on immune and stromal scores. Function enrichment analyses were performed to show the underlying mechanistic insights of these tumor microenvironment related genes. Kaplan-Meier survival analysis was used for evaluating the prognostic power. Gene-Pathway interaction network analysis and cellular heterogeneity analysis of tumor microenvironment were also performed. Gene set enrichment analysis was performed for signal gene pathway analysis. Protein data from The Cancer Genome Atlas were used for validation.

Dual phosphorylation of protein phosphatase PPM1H promotes dephosphorylation of Smad1 in cellulo

Protein phosphatase PPM1H is known to participate in various biological or pathophysiological mechanisms. However, little is known about the molecular mechanisms of its regulation. In this study, we investigated the protein kinases that directly phosphorylate PPM1H, identifying them as cAMP-dependent protein kinase (PKA) and Ca²⁺/calmodulin-dependent protein kinase I (CaMKI). In vitro and in silico analyses showed that the phosphorylation sites of PPM1H by PKA and CaMKI were Ser-123 and Ser-210, respectively. The phosphorylation state of PPM1H in cells exhibited the kinase activator- and inhibitor-dependent changes. In mouse neuroblastoma Neuro2a cells, phosphorylation of Ser-210 was much higher in the phospho-mimetic mutant (S123D) than in the non-phosphorylatable mutant (S123A) when they were treated with ionomycin. This suggests that a hierarchical phosphorylation, with initial phosphorylation of Ser-123 promoting subsequent phosphorylation of Ser-210, occurs in these neuron-like cells. Moreover, in cell-based assay a PPM1H(S123A/S210A) double mutant barely dephosphorylated Smad1, a transcription factor known as an endogenous substrate of PPM1H. These results suggest that cAMP and Ca²⁺/calmodulin regulate dephosphorylation of Smad1 through the dual phosphorylation of PPM1H at Ser-123 and Ser-210.

PPM1H phosphatase counteracts LRRK2 signaling by selectively dephosphorylating Rab proteins

Mutations that activate LRRK2 protein kinase cause Parkinson's disease. LRRK2 phosphorylates a subset of Rab GTPases within their Switch-II motif controlling interaction with effectors. An siRNA screen of all human protein phosphatases revealed that a poorly studied protein phosphatase, PPM1H, counteracts LRRK2 signaling by specifically dephosphorylating Rab proteins. PPM1H knockout increased endogenous Rab phosphorylation and inhibited Rab dephosphorylation in human A549 cells. Overexpression of PPM1H suppressed LRRK2-mediated Rab phosphorylation. PPM1H also efficiently and directly dephosphorylated Rab8A in biochemical studies. A "substrate-trapping" PPM1H mutant (Asp288Ala) binds with high affinity to endogenous, LRRK2-phosphorylated Rab proteins, thereby blocking dephosphorylation seen upon addition of LRRK2 inhibitors. PPM1H is localized to the Golgi and its knockdown suppresses primary cilia formation, similar to pathogenic LRRK2. Thus, PPM1H acts as a key modulator of LRRK2 signaling by controlling dephosphorylation of Rab proteins. PPM1H activity enhancers could offer a new therapeutic approach to prevent or treat Parkinson's disease.