Helicase-like transcription factor-deletion from the tumor microenvironment in a cell line-derived xenograft model of colorectal cancer reprogrammed the human transcriptome-S-nitroso-proteome to promote inflammation and redirect metastasis

AMPA receptor modulation through sequential treatment with perampanel and aniracetam mitigates post-stroke damage in experimental model of ischemic stroke

The present study evaluates the effect of modulating α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor (AMPAR) by inhibiting them in the acute phase and activating them in the sub-acute phase on post-stroke recovery in middle cerebral artery occlusion (MCAo) model of stroke in rats. After 90 min of MCAo, perampanel (an AMPAR antagonist, 1.5 mg/kg i.p) and aniracetam (an AMPA agonist, 50 mg/kg i.p.) were administered for different durations after MCAo. Later, after obtaining the best time point for the antagonist and the agonist treatment protocols, sequential treatment with perampanel and aniracetam were given, and the effect on neurological damage and post stroke recovery were assessed. Perampanel and aniracetam significantly protected MCAo-induced neurological damage and diminished the infarct percentage. Furthermore, treatment with these study drugs improved the motor coordination and grip strength. Sequential treatment with perampanel and aniracetam reduced the infarct percentage as assessed by MRI. Moreover, these compounds diminished the inflammation via reducing the levels of pro-inflammatory cytokines (TNF-α, IL-1β) and increasing the levels of anti-inflammatory cytokine (IL-10) along with reductions in GFAP expression. Moreover, the neuroprotective markers (BDNF and TrkB) were found to be significantly increased. Levels of apoptotic markers (Bax, cleaved-caspase-3; Bcl2 and TUNEL positive cells) and neuronal damage (MAP-2) were normalized with the AMPA antagonist and agonist treatment. Expressions of GluR1 and GluR2 subunits of AMPAR were significantly enhanced with sequential treatment. The present study thus showed that modulation of AMPAR improves neurobehavioral deficits and reduces the infarct percentage through anti-inflammatory, neuroprotective and anti-apoptotic effects.

Intricate confrontation: Research progress and application potential of TRIM family proteins in tumor immune escape

BACKGROUND

Tripartite motif (TRIM) family proteins have more than 80 members and are widely found in various eukaryotic cells. Most TRIM family proteins participate in the ubiquitin-proteasome degradation system as E3-ubiquitin ligases; therefore, they play pivotal regulatory roles in the occurrence and development of tumors, including tumor immune escape. Due to the diversity of functional domains of TRIM family proteins, they can extensively participate in multiple signaling pathways of tumor immune escape through different substrates. In current research and clinical contexts, immune escape has become an urgent problem. The extensive participation of TRIM family proteins in curing tumors or preventing postoperative recurrence and metastasis makes them promising targets.

AIM OF REVIEW

The aim of the review is to make up for the gap in the current research on TRIM family proteins and tumor immune escape and propose future development directions according to the current progress and problems.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This up-to-date review summarizes the characteristics and biological functions of TRIM family proteins, discusses the mechanisms of TRIM family proteins involved in tumor immune escape, and highlights the specific mechanism from the level of structure-function-molecule-pathway-phenotype, including mechanisms at the level of protein domains and functions, at the level of molecules and signaling pathways, and at the level of cells and microenvironments. We also discuss the application potential of TRIM family proteins in tumor immunotherapy, such as possible treatment strategies for combination targeting TRIM family protein drugs and checkpoint inhibitors for improving cancer treatment.

Helicase-like transcription factor (HLTF)-deleted CDX/TME model of colorectal cancer increased transcription of oxidative phosphorylation genes and diverted glycolysis to boost S-glutathionylation in lymphatic intravascular metastatic niches

Helicase-like transcription factor (HLTF) also known as SMARCA3, protects genome integrity. A tumor suppressor, HLTF is expressed in tumor cells but not in the tumor microenvironment (TME) in early-stage colorectal cancer (CRC). With disease progression, there is high concordance between epigenetic silencing of HLTF in CRC cells and negligible HLTF expression in the TME. We developed a cell line-derived xenograft (CDX) model and show for the first time that HLTF-deletion in cancer cells and the TME results in metabolic reprogramming that mitigates oxidative stress in lymphatic intravascular metastatic niches. The two metabolic pathways that derive energy from glucose-glycolysis and oxidative phosphorylation (OXPHOS)-are variously utilized by cancer cells depending upon the TME. HIF-1α, a master regulator of glycolysis, was eliminated from a role in reprogramming metabolism to satisfy CDX energetic requirements by RNAseq and spatial transcriptomics. Variability in the gut microbiome, with a putative role in altered metabolism, was also eliminated. HLTF-deleted cancer cells recovered from DNA damage at a transcriptomic level induction of DNA repair and OXPHOS genes linked to an amoeboid-associated phenotype at the tumor border (confocal microscopy). HLTF-deleted cancer and endothelial cells of lymphatic (PDPN) intravascular niches in the TME shared a site-specific protein S-glutathionylation signature (2D DIGE, MALDI-TOF/TOF mass spectrometry) for three glycolytic enzymes (PGK1 Cys379/380, PGAM1 Cys55, ENOA1 Cys119) that diverted glycolysis in support of continued glutathione biosynthesis. The collective absence of HLTF/Hltf from tumor and TME achieved redox homeostasis throughout the CDX and promoted metastasis.

Helicase-like transcription factor (Hltf)-deletion activates Hmgb1-Rage axis and granzyme A-mediated killing of pancreatic β cells resulting in neonatal lethality

Epigenetic mechanisms are integral to pancreatic β cell function. Promoter hypermethylation of the helicase like-transcription factor (HLTF) gene-a component of the cellular DNA damage response that contributes to genome stability-has been implicated in age-associated changes in β cells. To study HLTF, we generated global and β cell-specific (β) Hltf knockout (KO) immune competent (IC) and immune deficient (ID) Rag2-/IL2- mice. IC global and β Hltf KO mice were neonatal lethal whereas ID global and β Hltf KO newborn mice had normal survival. This focused our investigation on the effects of Rag2 interruption with common gamma chain interruption on β cell function/survival. Three-way transcriptomic (RNAseq) analyses of whole pancreata from IC and ID newborn β Hltf KO and wild type (Hltf +/+) controls combined with spatially resolved transcriptomic analysis of formalin fixed paraffin embedded tissue, immunohistochemistry and laser scanning confocal microscopy showed DNA damage caused by β Hltf KO in IC mice upregulated the Hmgb1-Rage axis and a gene signature for innate immune cells. Perforin-delivered granzyme A (GzmA) activation of DNase, Nme1, showed damaged nuclear single-stranded DNA (γH2AX immunostaining). This caspase-independent method of cell death was supported by transcriptional downregulation of Serpinc1 gene that encodes a serine protease inhibitor of GzmA. Increased transcriptional availability of complement receptors C3ar1 and C5ar1 likely invited crosstalk with Hmgb1 to amplify inflammation. This study explores the complex dialog between β cells and immune cells during development. It has implications for the initiation of type I diabetes in utero when altered gene expression that compromises genome stability invokes a localized inflammatory response.

Proteome profiling of endogenous and potential S-nitrosylation in colorectal cancer

Background

As a common cancer with high incidence rate and mortality, colorectal cancer (CRC) is seriously threatening human health. S-nitrosylation (SNO) proteins mediated by nitric oxide (NO) has important implications in the genesis, progression, and apoptosis of CRC. It's worth noting that the SNO proteins also play an important role in the tumor endocrine and metabolic pathways of CRC.

Materials and methods

In this study, the protein extracts of human tissues and cell lines were treated by biotin switch technology and magnetic beads enrichment. The proteomic results of endogenous and potential SNO proteins were analyzed by mass spectrometry (MS). Through the comparison and analysis of MS results, Gene Ontology (GO) analysis, and literatures, some endogenous and potential SNO proteins were identified in CRC, which were closely related to the tumor endocrine and metabolic pathways, the apoptotic signaling pathways, protein maturation, and other biological processes of the proliferation and apoptosis of CRC cells.

Results

A total of 19 proteins containing potential or endogenous SNO sites were detected in both human cancer tissue and SW 480 cells. Through the cross validation of MS results, GO analysis, and literatures, several SNO proteins were identified frequently in CRC, such as the actin, cytoplasmic 1 (ACTB), peroxiredoxin-4 (PRDX4), protein S100A8 (S100A8), pyruvate kinase PKM (PKM), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), which were closely related to the tumor endocrine and metabolic pathways and the apoptotic signaling pathways of CRC.

Conclusion

Different CRC cells and tissues contained potential and endogenous SNO modified proteins. In addition, some SNO proteins could participate in the proliferation, metastasis and apoptosis of CRC by regulating the tumor endocrine and metabolic pathways.

Novel Methylation Biomarkers for Colorectal Cancer Prognosis

Colorectal cancer (CRC) comprises the third most common cancer worldwide and the second regarding number of deaths. In order to make a correct and early diagnosis to predict metastasis formation, biomarkers are an important tool. Although there are multiple signaling pathways associated with cancer progression, the most recognized are the MAPK pathway, p53 pathway, and TGF-β pathway. These pathways regulate many important functions in the cell, such as cell cycle regulation, proliferation, differentiation, and metastasis formation, among others. Changes in expression in genes belonging to these pathways are drivers of carcinogenesis. Often these expression changes are caused by mutations; however, epigenetic changes, such as DNA methylation, are increasingly acknowledged to play a role in the deregulation of oncogenic genes. This makes DNA methylation changes an interesting biomarkers in cancer. Among the newly identified biomarkers for CRC metastasis INHBB, SMOC2, BDNF, and TBRG4 are included, all of which are highly deregulated by methylation and closely associated with metastasis. The identification of such biomarkers in metastasis of CRC may allow a better treatment and early identification of cancer formation in order to perform better diagnostics and improve the life expectancy.