Collaboration of MYC and RUNX2 in lymphoma simulates T-cell receptor signaling and attenuates p53 pathway activity

SMYD2 aggravates gastrointestinal stromal tumor via upregulation of EZH2 and downregulation of TET1

SMYD2, as an oncogene, has been involved in multiple types of cancer, but the potential role of SMYD2 in gastrointestinal stromal tumors (GIST) remains enigmatic and requires further investigation. Hence, this study was conducted with the main objective of analyzing the effect of SMYD2 on GIST. GIST and adjacent normal tissues were collected from 46 patients with GIST where the expression of EZH2, SMYD2, and TET1 was determined, followed by the analysis of their interactions. The functional role of SMYD2 in cell biological functions was determined using a loss-of-function assay in GIST-T1 cells. Nude mouse xenograft experiments were performed to verify the role of the SMYD2/EZH2/TET1 axis in GIST in vivo. EZH2 was upregulated in GIST tissues and cell lines, which was positively correlated with SMYD2 expression and inversely correlated with TET1 expression in GIST tissues. EZH2 silencing due to SMYD2 inhibition reduced GIST-T1 cell proliferation and accelerated cell senescence. EZH2 repressed TET1 expression by promoting H3K27me3 methylation in the TET1 promoter region. TET1 inhibition reversed the effect of EZH2 silencing on the biological functions of GIST-T1 cells. In vivo data further revealed the promoting effect of SMYD2 on the progression of GIST by regulating the EZH2/TET1 axis. Overall, this study demonstrates that SMYD2 can increase EZH2 expression while suppressing TET1 expression, thus accelerating GIST, and creating new treatment opportunities for GIST.

The Mechanism of Nano-Particles Intervening Invasion and Metastasis of Lymphoma Based on Autophagy Targeted with miR-36b and Orienteering Analysis on Apoptosis Gene

Whether the expression of gene P53 related with autophagy and apoptosis and action was regulated by miR-36b was discussed in our study. And the action of orienteering nano-particles on intervening invasion and metastasis of lymphoma was analyzed. The normal lymphoid tissue collected from the patients with simple lymphatic hyperplasia was set as control. The lymphoma samples from patients with early indolent lymphoma were collected. The level of mRNA in miR-36b and P53 was detected by PCR. The level of P53 protein and level of mRNA in miR-36b and P53 among normal lymphoid cell, cell strain of low metastatic lymphoma and cell strain of high metastatic lymphoma was compared. They were divided into four groups: miR-NC group, orienteering nano-particles’ group, siRNA-NC group and siRNA-P53 group. The cell proliferative capacity was detected by FCM. The quantity of cell invasion and metastasis was detected by transwell. The expression quantity of P53 mRNA in lymphoma tissue was increased obviously compared with control group. The expression of miR-36b was lower while the expression of P53 was higher along with the later staging of TNM. And the express was related with the staging of TNM. The expression quantity of P53 mRNA in lymphoma cell was higher in normal cell notably. But expression quantity of miR-36b in lymphoma cell was lower in normal cell notably. The decreased of expression of miR-36b and increased of expression of P53 was related with enhancing the ability of invasion and metastasis of lymphoma cells.

The SMYD family proteins in immunology: An update of their obvious and non-obvious relations with the immune system

Epigenetics is an emerging field, due to its relevance in the regulation of a wide range of biological processes. The Su(Var)3–9, Enhancer-of-zeste and Trithorax (SET) and Myeloid, Nervy, and DEAF-1 (MYND) domain-containing (SMYD) proteins, named SMYD1, SMYD2, SMYD3, SMYD4 and SMYD5, are enzymes that catalyse methylation of histone and non-histone substrates, thereby playing a key role in gene expression regulation in many biological contexts, such as muscle development and physiology, haematopoiesis and many types of cancer. This review focuses on a relatively unexplored aspect of SMYD family members - their relation with immunology. Here, immunology is defined in the broadest sense of the word, including basic research on macrophage function or host immunity against pathogen infection, as well as clinical studies, most of which are centred on blood cancers.

Oncogenic RUNX3: A Link between p53 Deficiency and MYC Dysregulation

The RUNX transcription factors serve as master regulators of development and are frequently dysregulated in human cancers. Among the three family members, RUNX3 is the least studied, and has long been considered to be a tumor-suppressor gene in human cancers. This idea is mainly based on the observation that RUNX3 is inactivated by genetic/epigenetic alterations or protein mislocalization during the initiation of tumorigenesis. Recently, this paradigm has been challenged, as several lines of evidence have shown that RUNX3 is upregulated over the course of tumor development. Resolving this paradox and understanding how a single gene can exhibit both oncogenic and tumor-suppressive properties is essential for successful drug targeting of RUNX. We propose a simple explanation for the duality of RUNX3: p53 status. In this model, p53 deficiency causes RUNX3 to become an oncogene, resulting in aberrant upregulation of MYC.

Disrupting MLV integrase:BET protein interaction biases integration into quiescent chromatin and delays but does not eliminate tumor activation in a MYC/Runx2 mouse model

Murine leukemia virus (MLV) integrase (IN) lacking the C-terminal tail peptide (TP) loses its interaction with the host bromodomain and extraterminal (BET) proteins and displays decreased integration at promoter/enhancers and transcriptional start sites/CpG islands. MLV lacking the IN TP via an altered open reading frame was used to infect tumorigenesis mouse model (MYC/Runx2) animals to observe integration patterns and phenotypic effects, but viral passage resulted in the restoration of the IN TP through small deletions. Mice subsequently infected with an MLV IN lacking the TP coding sequence (TP^-) showed an improved median survival by 15 days compared to wild type (WT) MLV infection. Recombination with polytropic endogenous retrovirus (ERV), Pmv20, was identified in seven mice displaying both fast and slow tumorigenesis, highlighting the strong selection within the mouse to maintain the full-length IN protein. Mapping the genomic locations of MLV in tumors from an infected mouse with no observed recombination with ERVs, TP^-16, showed fewer integrations at TSS and CpG islands, compared to integrations observed in WT tumors. However, this mouse succumbed to the tumor in relatively rapid fashion (34 days). Analysis of the top copy number integrants in the TP^-16 tumor revealed their proximity to known MLV common insertion site genes while maintaining the MLV IN TP^- genotype. Furthermore, integration mapping in K562 cells revealed an insertion preference of MLV IN TP^- within chromatin profile states associated with weakly transcribed heterochromatin with fewer integrations at histone marks associated with BET proteins (H3K4me1/2/3, and H3K27Ac). While MLV IN TP^- showed a decreased overall rate of tumorigenesis compared to WT virus in the MYC/Runx2 model, MLV integration still occurred at regions associated with oncogenic driver genes independently from the influence of BET proteins, either stochastically or through trans-complementation by functional endogenous Gag-Pol protein.

Many different retroviruses, including murine leukemia virus (MLV), are used as vectors for human gene therapy and cancer immunotherapies (CAR-T) because of their stable and efficient delivery of genetic material into the host DNA. However, this process can result in activation and/or disruption of cellular genes, which has resulted in the outgrowth of tumors in previous clinical trials. Of critical importance is the preferred location within the host genome at which the retrovirus integrates. Our study presents a modified MLV virus that has lost the ability to bind to the host BET proteins, the drivers of insertion at promoter/enhancer regions of highly activated genes. This is the first direct study within an animal model to examine whether infection with this type of modified MLV virus affects tumor progression. We found that the modified virus improved the survival of the well-characterized MYC/Runx2 mouse compared to infections with the wild-type MLV. Most modified viral integrants mapped into less active regions of the genome, but some integration events still occurred near cancer-related genes. Thus, while the modified MLV virus can be a safer vector than the wildtype virus, it still maintains the potential to activate oncogenes. This study provides new insights on how to improve the safety of MLV retroviral vectors.

Collaboration of MYC and RUNX2 in lymphoma simulates T-cell receptor signaling and attenuates p53 pathway activity

MYC and RUNX oncogenes each trigger p53‐mediated failsafe responses when overexpressed in vitro and collaborate with p53 deficiency in vivo. However, together they drive rapid onset lymphoma without mutational loss of p53. This phenomenon was investigated further by transcriptomic analysis of premalignant thymus from RUNX2/MYC transgenic mice. The distinctive contributions of MYC and RUNX to transcriptional control were illustrated by differential enrichment of canonical binding sites and gene ontology analyses. Pathway analysis revealed signatures of MYC, CD3, and CD28 regulation indicative of activation and proliferation, but also strong inhibition of cell death pathways. In silico analysis of discordantly expressed genes revealed Tnfsrf8/CD30, Cish, and Il13 among relevant targets for sustained proliferation and survival. Although TP53 mRNA and protein levels were upregulated, its downstream targets in growth suppression and apoptosis were largely unperturbed. Analysis of genes encoding p53 posttranslational modifiers showed significant upregulation of three genes, Smyd2, Set, and Prmt5. Overexpression of SMYD2 was validated in vivo but the functional analysis was constrained by in vitro loss of p53 in RUNX2/MYC lymphoma cell lines. However, an early role is suggested by the ability of SMYD2 to block senescence‐like growth arrest induced by RUNX overexpression in primary fibroblasts.