The role of phosphorylation of MLF2 at serine 24 in BCR-ABL leukemogenesis

CPSF4-mediated regulation of alternative splicing of HMG20B facilitates the progression of triple-negative breast cancer

BACKGROUND

Aberrant alternative splicing (AS) contributes to tumor progression. A crucial component of AS is cleavage and polyadenylation specificity factor 4 (CPSF4). It remains unclear whether CPSF4 plays a role in triple-negative breast cancer (TNBC) progression through AS regulation. In this study, our objective is to investigate the prognostic value of CPSF4 and pinpoint pivotal AS events governed by CPSF4 specifically in TNBC.

METHODS

We examined the expression levels and prognostic implications of CPSF4 in patients diagnosed with TNBC through public databases. CPSF4-interacting transcripts, global transcriptome, and alternative splicing were captured through RNA immunoprecipitation sequencing (RIP-seq) and RNA sequencing (RNA-seq). The top 10 CPSF4-regulated alternative splicing events (ASEs) were validated using qRT-PCR. TNBC cells transfected with high mobility group 20B (HMG20B) siRNA were subjected to CCK-8 and transwell assays.

RESULTS

In TNBC, CPSF4 exhibited heightened expression levels and was correlated with unfavorable prognosis. Overexpression of CPSF4 significantly promoted colony formation and migration, whereas knockdown of CPSF4 had the opposite effect. Inhibition of CPSF4 altered the transcriptome profile of MDA-MB-231 cells. CPSF4-regulated numerous genes showed enrichment in cancer-related functional pathways, including mRNA processing, cell cycle, RNA transport, mRNA surveillance pathway, and apoptosis. CPSF4-regulated ASEs were highly validated by qRT-PCR. CPSF4 modulated selective splicing events by inhibiting alternative 3' splice site events of HMG20B and promoted cell proliferation, migration, and invasion.

CONCLUSION

CPSF4 promotes TNBC progression by regulating AS of HMG20B. These findings contribute to the development of more useful prognostic, diagnostic and potentially therapeutic biomarkers for TNBC.

MLF2 Negatively Regulates P53 and Promotes Colorectal Carcinogenesis

Inactivation of the p53 pathway is linked to a variety of human cancers. As a critical component of the p53 pathway, ubiquitin-specific protease 7 (USP7) acts as a deubiquitinase for both p53 and its ubiquitin E3 ligase mouse double minute 2 homolog. Here, myeloid leukemia factor 2 (MLF2) is reported as a new negative regulator of p53. MLF2 interacts with both p53 and USP7. Via these interactions, MLF2 inhibits the binding of USP7 to p53 and antagonizes USP7-mediated deubiquitination of p53, thereby leading to p53 destabilization. Functionally, MLF2 plays an oncogenic role in colorectal cancer, at least partially, via the negative regulation of p53. Clinically, MLF2 is elevated in colorectal cancer and its high expression is associated with poor prognosis in patients with colorectal cancer. In wild-type-p53-containing colorectal cancer, MLF2 and p53 expressions are inversely correlated. These findings establish MLF2 as an important suppressor of p53 function. The study also reveals a critical role for the MLF2-p53 axis in promoting colorectal carcinogenesis.

Pierre C, Bimschleger H, Gao J, Cheng R, Polesskaya O, Solberg Woods LC, Palmer AA, Chen H. Genome-Wide Association Study on Three Behaviors Tested in an Open Field in Heterogeneous Stock Rats Identifies Multiple Loci Implicated in Psychiatric Disorders

Many personality traits are influenced by genetic factors. Rodents models provide an efficient system for analyzing genetic contribution to these traits. Using 1,246 adolescent heterogeneous stock (HS) male and female rats, we conducted a genome-wide association study (GWAS) of behaviors measured in an open field, including locomotion, novel object interaction, and social interaction. We identified 30 genome-wide significant quantitative trait loci (QTL). Using multiple criteria, including the presence of high impact genomic variants and co-localization of cis-eQTL, we identified 17 candidate genes (Adarb2, Ankrd26, Cacna1c, Cacng4, Clock, Ctu2, Cyp26b1, Dnah9, Gda, Grxcr1, Eva1a, Fam114a1, Kcnj9, Mlf2, Rab27b, Sec11a, and Ube2h) for these traits. Many of these genes have been implicated by human GWAS of various psychiatric or drug abuse related traits. In addition, there are other candidate genes that likely represent novel findings that can be the catalyst for future molecular and genetic insights into human psychiatric diseases. Together, these findings provide strong support for the use of the HS population to study psychiatric disorders.

Somatic copy number alteration predicts clinical benefit of lung adenocarcinoma patients treated with cytokine-induced killer plus chemotherapy

Somatic copy number alterations (SCNA), which are widespread in cancer, can predict the efficacy of immune checkpoint inhibitors in non-small-cell lung cancer (NSCLC). However, the usefulness of SCNA for predicting the survival of patients treated with cytokine-induced killer (CIK) cells or chemotherapy (CT) is unknown. This study aimed to explore the correlation between SCNA and clinical outcome in NSCLC patients treated with CIK + CT or CT alone. We performed whole-exome sequencing on 45 NSCLC patients treated with CIK + CT, as well as 305 NSCLC patients treated with CT alone, from The Cancer Genome Atlas, which showed SCNA had a superiority in predicting the progression-free survival (PFS) over tumor mutation burden (TMB) and SCNA + TMB in NSCLC patients treated with CIK + CT, especially in lung adenocarcinoma, while SCNA could not predict the efficacy of CT alone. Additionally, we investigated the association between SCNA and immune cell infiltration by RNA sequencing and immunohistochemistry. The results revealed that SCNA was negatively associated with the expression of dendritic cells. Collectively, this study revealed a negative correlation between SCNA and response to CIK + CT and showed that SCNA is a predictive indicator in LUAD patients treated with CIK + CT.

Proteomic and phosphoproteomic profiling of shammah induced signaling in oral keratinocytes

Shammah is a smokeless tobacco product often mixed with lime, ash, black pepper and flavorings. Exposure to shammah has been linked with dental diseases and oral squamous cell carcinoma. There is limited literature on the prevalence of shammah and its role in pathobiology of oral cancer. In this study, we developed a cellular model to understand the effect of chronic shammah exposure on oral keratinocytes. Chronic exposure to shammah resulted in increased proliferation and invasiveness of non-transformed oral keratinocytes. Quantitative proteomics of shammah treated cells compared to untreated cells led to quantification of 4712 proteins of which 402 were found to be significantly altered. In addition, phosphoproteomics analysis of shammah treated cells compared to untreated revealed hyperphosphorylation of 36 proteins and hypophosphorylation of 83 proteins (twofold, p-value ≤ 0.05). Bioinformatics analysis of significantly altered proteins showed enrichment of proteins involved in extracellular matrix interactions, necroptosis and peroxisome mediated fatty acid oxidation. Kinase-Substrate Enrichment Analysis showed significant increase in activity of kinases such as ROCK1, RAF1, PRKCE and HIPK2 in shammah treated cells. These results provide better understanding of how shammah transforms non-neoplastic cells and warrants additional studies that may assist in improved early diagnosis and treatment of shammah induced oral cancer.

Discovery of Berberine that Targetedly Induces Autophagic Degradation of both BCR-ABL and BCR-ABL T315I through Recruiting LRSAM1 for Overcoming Imatinib Resistance

PURPOSE

Imatinib, the breakpoint cluster region protein (BCR)/Abelson murine leukemia viral oncogene homolog (ABL) inhibitor, is widely used to treat chronic myeloid leukemia (CML). However, imatinib resistance develops in many patients. Therefore, new drugs with improved therapeutic effects are urgently needed. Berberine (BBR) is a potent BCR-ABL inhibitor for imatinib-sensitive and -resistant CML.

EXPERIMENTAL DESIGN

Protein structure analysis and virtual screening were used to identify BBR targets in CML. Molecular docking analysis, surface plasmon resonance imaging, nuclear magnetic resonance assays, and thermoshift assays were performed to confirm the BBR target. The change in BCR-ABL protein expression after BBR treatment was assessed by Western blotting. The effects of BBR were assessed in vitro in cell lines, in vivo in mice, and in human CML bone marrow cells as a potential strategy to overcome imatinib resistance.

RESULTS

We discovered that BBR bound to the protein tyrosine kinase domain of BCR-ABL. BBR inhibited the activity of BCR-ABL and BCR-ABL with the T315I mutation, and it also degraded these proteins via the autophagic lysosome pathway by recruiting E3 ubiquitin-protein ligase LRSAM1. BBR inhibited the cell viability and colony formation of CML cells and prolonged survival in CML mouse models with imatinib sensitivity and resistance.

CONCLUSIONS

The results show that BBR directly binds to and degrades BCR-ABL and BCR-ABL T315I via the autophagic lysosome pathway by recruiting LRSAM1. The use of BBR is a new strategy to improve the treatment of patients with CML with imatinib sensitivity or resistance.See related commentary by Elf, p. 3899.