Cell Death & Disease最新文献

Extrahepatic cholangiocarcinoma (ECCA) is a malignant tumor. The precise role of T-cell immunoreceptor with Ig and ITIM domains (TIGIT), an emerging immunosuppressive receptor, in ECCA, and its impact on CD8+ T cell exhaustion (Tex) remains unclear. We performed single-cell RNA sequencing (scRNA-seq) to characterize tumor-infiltrating lymphocytes (TILs) isolated from ECCA. We found that TIGIT was significantly overexpressed in TOX+CD8 T cells. Tissue microarray and immunohistochemistry staining demonstrated that increased TIGIT expression was associated with poorer patient survival. Flow cytometry analysis revealed that TIGIT+CD8+ T cells exhibited decreased TNF-α, IFN-γ, and TCF-1 expression, accompanied by elevated PD-1 and TIM-3 expression compared to TIGIT-CD8+ T cells. In the patient-derived xenograft (PDX) model, the anti-TIGIT treatment group demonstrated reduced tumor weight, enhanced CD8 frequency, and an increased IFN-γ proportion compared to the PBS treatment group. The TIGIT antibody-treated group exhibited a notably higher fraction of GRZB, and anti-TIGIT treatment led to elevated TCF-1 protein levels and decreased protein levels of TOX1 and NR4A1. Moreover, TIGIT+CD8 T cells from TILs appear to be in a state of exhaustion with low potential killing capacity in ECCA, as shown by scRNA-seq. Taken together, the present study underscores the significant role of TIGIT in ECCA, contributing to T cell exhaustion and a compromised CD8+ T cell immune response. Targeting TIGIT presents a promising therapeutic avenue to enhance the CD8+ T-cell response, thereby potentially improving ECCA therapeutic benefits.

Ubiquitination is a posttranslational modification that regulates tumour progression-associated proteins through the ubiquitin‒proteasome system, making E3 ligases potential antitumour targets. Here, we report that TRIM8, a member of the TRIM family and an E3 ligase, can act as a tumour suppressor in non-small cell lung cancer (NSCLC). Both gain- and loss-of-function experiments revealed that TRIM8 inhibits the proliferation, colony formation, migration and invasion of NSCLC cells. Experiments with a xenograft model showed that TRIM8 expression suppresses tumour metastasis in vivo. Moreover, low expression of TRIM8 was associated with poor overall survival in both the Taiwanese and GEO lung cancer cohorts. TRIM8 overexpression in lung cancer cells reduced MYOF expression, and restoring MYOF rescued cell migration in TRIM8-overexpressing cells. TRIM8 targeted MYOF for K48-linked ubiquitination, facilitating proteasome-mediated degradation and subsequently suppressing the extracellular secretion of MMPs. Our results provide new insights into the contribution of TRIM8 to lung cancer progression, suggesting that TRIM8 is a new biomarker and a novel therapeutic target for lung cancer.

Mutation in genes involved in DNA replication continuously disrupt DNA replication and give rise to genomic instability, a critical driver of oncogenesis. To prevent leukemia, immature T lymphocytes with genomic instability often undergo rapid cell death during development. However, the mechanism by which immature T lymphocytes undergo rapid cell death upon genomic instability has been enigmatic. Here we show that zebrafish mcm5 mutation leads to DNA damage in immature T lymphocytes and the immature T cells sensitively undergo rapid cell death. Detailed analyses demonstrated that the immature T lymphocytes undergo rapid apoptosis via upregulation of tp53 and downregulation of bcl2 transcription in mcm5 mutants. Mechanistically, Mcm5 directly binds to Stat1a and facilitates its phosphorylation to enhance bcl2a expression under the conditions of DNA replication stress. However, in mcm5 mutants, the absence of the Mcm5-Stat1 complex decreases Stat1 phosphorylation and subsequent bcl2a transcription, accelerating apoptosis of immature T lymphocytes with genomic instability. Furthermore, our study shows that the role of Mcm5 in T-cell development is conserved in mice. In conclusion, our work identifies a role of Mcm5 in regulating T cell development via Stat1-Bcl2 cascade besides its role in DNA replication, providing a kind of mechanism by which immature T cells with gene mutation-induced DNA damage are rapidly cleared during T lymphocyte development.

Proline-rich 15 (PRR15) is a protein primarily known for its role in placental development. This study investigates the expression, functional significance, and underlying mechanisms of PRR15 in non-small cell lung cancer (NSCLC). Our findings demonstrate significantly elevated PRR15 expression in NSCLC tissues compared to normal lung parenchyma, with higher expression correlating with adverse clinical outcomes. Single-cell RNA sequencing confirmed PRR15 overexpression within the malignant tumor cell population. PRR15 expression was elevated in NSCLC tissues from locally treated patients and in a panel of primary and established NSCLC cells. PRR15 depletion using shRNA or CRISPR/Cas9-mediated knockout significantly suppressed proliferation and migration, while promoting apoptosis in various NSCLC cells. Conversely, ectopic PRR15 overexpression using a lentiviral construct enhanced cell proliferation and migration. Mechanistic investigations implicated PRR15 in the activation of the Akt-mTOR signaling pathway. Inhibition of PRR15 expression via shRNA or CRISPR/Cas9-mediated knockout resulted in decreased Akt and S6K phosphorylation, while PRR15 overexpression led to augmented Akt-S6K signaling in primary human NSCLC cells. In vivo studies using xenograft models further validated the oncogenic role of PRR15, demonstrating that PRR15 knockdown suppressed tumor growth and attenuated Akt-mTOR activation. These findings collectively highlight the potential of PRR15 as a novel oncogenic driver and therapeutic target in NSCLC.

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. The 5-methylcytosine (m5C) RNA methyltransferase NSUN2 is involved in cell proliferation and metastasis and is upregulated in a variety of cancers. However, the biological function and regulatory mechanism of NSUN2-mediated m5C modification have not been well studied in HCC. Our results showed that NSUN2 is upregulated and associated with poor prognosis in HCC patients after hepatectomy. NSUN2 overexpression significantly promoted HCC growth and metastasis, whereas NSUN2 knockdown had the opposite effect. m5C RNA immunoprecipitation sequencing (m5C-RIP-Seq) revealed that m5C hypermethylation correlates with mRNA overexpression and that NSUN2-mediated m5C hypermethylation promotes metabolism in HCC patients. Mechanistically, our data revealed that PKM2, a terminal enzyme in the glycolytic pathway, is a downstream target of NSUN2-mediated m5C modification. Specifically, NSUN2 could stabilize PKM2 mRNA by increasing the m5C level of the m5C site C773 in the 3'-UTR of PKM2 mRNA. In addition, rescue assays revealed that NSUN2 promotes HCC glycolysis and progression by upregulating PKM2. In conclusion, this study revealed that NSUN2-mediated m5C modification promotes glycolysis and the progression of hepatocellular carcinoma by stabilizing PKM2 mRNA, and provides a potential prognostic factor and therapeutic target for HCC patients.

Metastasis is a major challenge for colorectal cancer (CRC) treatment. In this study, we identified autophagy activation as a prognostic indicator in CRC and observed that the expression of key autophagy proteins is elevated in metastatic and recurrent cases. Our subsequent goal was to identify potential genes associated with the autophagy panel and assess their prognostic significance, biological roles, and mechanisms in CRC metastasis. Among the candidates, CENPF emerged as the top gene in our screening process. We found that CENPF expression was preferentially elevated in CRC tissues compared to adjacent normal tissues, with significantly higher levels in CRC patients with tumor recurrence. Furthermore, a multicenter cohort study demonstrated that upregulated CENPF expression was strongly associated with poorer disease-free survival in CRC. Functional experiments showed that CENPF knockdown inhibited CRC cell invasion and metastasis both in vitro and in vivo. Intriguingly, we found CENPF undergoes degradation in CRC via the ubiquitination-proteasome pathway. Mechanistically, we observed that USP4 interacted with and stabilized CENPF via deubiquitination. Furthermore, USP4-mediated CENPF upregulation was critical regulators of metastasis of CRC. Examination of clinical samples confirmed that USP4 expression positively correlates with CENPF protein expression, but not mRNA transcript levels. Taken together, this study describes a novel USP4-CENPF signaling axis which is crucial for CRC metastasis, potentially serving as a therapeutic target and a promising prognostic biomarker for CRC.

RNA-based therapeutics highlighted novel approaches to target either coding or noncoding molecules for multiple diseases treatment. In breast cancer (BC), a multitude of deregulated long noncoding RNAs (lncRNAs) have been identified as potential therapeutic targets also in the context of antiestrogen resistance, and the RNA binding activity of the estrogen receptor α (ERα) points additional potential candidates to interfere with estrogenic signaling. A set of lncRNAs was selected among ERα-associated RNAs in BC cell nuclei due to their roles in processes such as transcriptional regulation and epigenetic chromatin modifications. Native immunoprecipitation of nuclear ERα-interacting RNAs coupled to NGS (RIP-Seq) was performed in MCF-7 cells, leading to the identification of essential lncRNAs interacting with the receptor in multi-molecular regulatory complexes. Among these, PVT1, FGD5-AS1 and EPB41L4A-AS1 were selected for further investigation. Functional assays and transcriptome analysis following lncRNA knock-down indicated PVT1 as the master modulator of some of the most relevant BC hallmarks, such as cell proliferation, apoptosis, migration and response to hypoxia. In addition, targeted experiments identified PVT1 as a key factor in the composition of PRC2-ERα network involved in downregulation of tumor suppressor genes, including BTG2.

Sterile inflammation resulting in an altered immune response is a key determinant of renal injury in diabetic nephropathy (DN). In this investigation, we evaluated the hypothesis that hyperglycemic conditions augment the pro-inflammatory immune response in the kidney by promoting podocyte-specific expression of the stress response protein regulated in development and DNA damage response 1 (REDD1). In support of the hypothesis, streptozotocin (STZ)-induced diabetes increased REDD1 protein abundance in the kidney concomitant with renal immune cell infiltration. In diabetic mice, administration of the SGLT2 inhibitor dapagliflozin was followed by reductions in blood glucose concentration, renal REDD1 protein abundance, and immune cell infiltration. In contrast with diabetic REDD1^+/+ mice, diabetic REDD1^-/- mice did not exhibit albuminuria, increased pro-inflammatory factors, or renal macrophage infiltration. In cultured human podocytes, exposure to hyperglycemic conditions promoted REDD1-dependent activation of NF-κB signaling. REDD1 deletion in podocytes attenuated both the increase in chemokine expression and macrophage chemotaxis under hyperglycemic conditions. Notably, podocyte-specific REDD1 deletion prevented the pro-inflammatory immune cell infiltration in the kidneys of diabetic mice. Furthermore, exposure of podocytes to hyperglycemic conditions promoted REDD1-dependent pyroptotic cell death, evidenced by an NLRP3-mediated increase in caspase-1 activity and LDH release. REDD1 expression in podocytes was also required for an increase in pyroptosis markers in the glomeruli of diabetic mice. The data support that podocyte-specific REDD1 is necessary for chronic NF-κB activation in the context of diabetes and raises the prospect that therapies targeting podocyte-specific REDD1 may be helpful in DN.