SHF Acts as a Novel Tumor Suppressor in Glioblastoma Multiforme by Disrupting STAT3 Dimerization

Bergaptol inhibits glioma cell proliferation and induces apoptosis via STAT3/Bcl-2 pathway

Glioblastoma (GBM) is the most common primary malignant brain tumour and lacks therapeutic options with significant effects. The aberrant activation of STAT3 is a critical factor in glioma progression via activating multiple signalling pathways that promote glioma. Among them, the antiapoptotic gene Bcl-2 could be upregulated by p-STAT3, which is an important reason for the continuous proliferation of glioma. We previously reported that bergaptol, a natural furanocoumarin widely found in citrus products, exerts antineuroinflammatory effects by inhibiting the overactivation of STAT3. Here, we aimed to evaluate whether bergaptol could promote glioma apoptosis by inhibiting the STAT3/Bcl-2 pathway. This study found that bergaptol inhibited the proliferation and migration of GBM cell lines (U87 and A172) and promoted apoptosis in vitro. We also found that bergaptol significantly inhibited the STAT3/Bcl-2 pathway in GBM cells. U87 cells were implanted intracranially into nude mice to establish a glioma model, and glioma-bearing mice were treated with bergaptol (40 mg/kg). Bergaptol treatment significantly inhibited glioma growth and prolonged the glioma-bearing mice's survival time. In addition, bergaptol administration also significantly inhibited the STAT3/Bcl-2 pathway of tumour tissue in vivo. Overall, we found that bergaptol could effectively play an antiglioma role by inhibiting STAT3/Bcl-2 pathway, suggesting the potential efficacy of bergaptol in treating glioma.

Interleukin-6 serves as a critical factor in various cancer progression and therapy

Interleukin-6 (IL-6), a pro-inflammatory cytokine, plays a crucial role in host immune defense and acute stress responses. Moreover, it modulates various cellular processes, including proliferation, apoptosis, angiogenesis, and differentiation. These effects are facilitated by various signaling pathways, particularly the signal transducer and activator of transcription 3 (STAT3) and Janus kinase 2 (JAK2). However, excessive IL-6 production and dysregulated signaling are associated with various cancers, promoting tumorigenesis by influencing all cancer hallmarks, such as apoptosis, survival, proliferation, angiogenesis, invasiveness, metastasis, and notably, metabolism. Emerging evidence indicates that selective inhibition of the IL-6 signaling pathway yields therapeutic benefits across diverse malignancies, such as multiple myeloma, prostate, colorectal, renal, ovarian, and lung cancers. Targeting key components of IL-6 signaling, such as IL-6Rs, gp130, STAT3, and JAK via monoclonal antibodies (mAbs) or small molecules, is a heavily researched approach in preclinical cancer studies. The purpose of this study is to offer an overview of the role of IL-6 and its signaling pathway in various cancer types. Furthermore, we discussed current preclinical and clinical studies focusing on targeting IL-6 signaling as a therapeutic strategy for various types of cancer.

The interface targeting hnRNPA2B1 regulates the repression of transthyretin against human retinal microvascular endothelial cells in high-glucose environment

BACKGROUND

The interaction between transthyretin (TTR) and heterogeneous nuclear ribonucleoprotein (hnRNP)A2B1 is involved in the neovascularization of human retinal microvascular endothelial cells (hRECs) under hyperglycemic conditions. However, whether the TTR-hnRNPA2B1 interface can be altered and how this protein-protein interaction and associated downstream pathways are regulated is unclear.

METHODS

We performed homologous sequential analysis and binding energy assays using Discovery Studio and designed substitution targeting three fragments of the interface (fragment 1: aa 34-39, -RKAADD-; fragment 2, aa 61-68, -EEEFVEGI-; and fragment 3, aa 96-102, -TANDSGP-) to disrupt or stabilize the TTR-hnRNPA2B1 complex and were subjected to Co-immunoprecipitation analysis. To investigate the effect of TTR-hnRNPA2B1 interface alterations on the physiological properties of hRECs, we performed CCK-8, EdU, migration, wound healing and tube formation assays. To study the downstream genes, we performed qRT-PCR and western blot.

RESULTS

Nineteen TTR substitutions were recombinantly expressed in soluble form, results indicated that reducing the binding energy stabilized the TTR-hnRNPA2B1, while increasing the binding energy had the opposite effect. The native TTR significantly prohibited the proliferation, DNA synthesis, migration and tube formation capacities of hRECs, while fragment 1 always reduced these effects. However, the I68R and D99R substitutions in fragments 2 and 3, respectively, increased the inhibitory effect of TTR. Furthermore, our qRT-PCR and western blot results showed that the expression and protein levels of STAT-4, miR-223-3p and FBXW7 were also regulated by the alteration of the TTR-hnRNPA2B1 interface.

CONCLUSION

This work suggests that the formation of the TTR-hnRNPA2B1 complex plays vital role in hyperglycemia, and modification of this interface regulates the TTR-mediated inhibition of hREC neovascularization via the STAT-4/miR-223-3p/FBXW7 pathway. This mechanism could have important implications for diabetic retinopathy treatment.

Acetylation halts missense mutant p53 aggregation and rescues tumor suppression in non-small cell lung cancers

TP53 mutations are ubiquitous with tumorigenesis in non-small cell lung cancers (NSCLC). By analyzing the TCGA database, we reported that TP53 missense mutations are correlated with chromosomal instability and tumor mutation burden in NSCLC. The inability of wild-type nor mutant p53 expression can't predict survival in lung cancer cohorts, however, an examination of primary NSCLC tissues found that acetylated p53 did yield an association with improved survival outcomes. Molecularly, we demonstrated that acetylation drove the ubiquitination and degradation of mutant p53 but enhanced stability of wild-type p53. Moreover, acetylation of a missense p53 mutation prevented the gain of oncogenic function observed in typical TP53 mutant-expressing cells and enhanced tumor suppressor functions. Consequently, acetylation inducer targeting of missense mutant p53 may be a viable therapeutic goal for NSCLC treatment and may improve the accuracy of current efforts to utilize p53 mutations in a prognostic manner.

Acetylcholine promotes chronic stress-induced lung adenocarcinoma progression via α5-nAChR/FHIT pathway

Chronic stress significantly elevates the expression levels of various neurotransmitters in the tumour microenvironment, thereby promoting the cell growth and metastasis of lung adenocarcinoma (LUAD). However, the role of chronic stress in the progression of LUAD remains unclear. In this study, we found that chronic restraint stress increases the levels of the neurotransmitter acetylcholine (ACh), and the α5-nicotinic acetylcholine receptor (α5-nAChR) and decreased fragile histidine triad (FHIT) expression in vivo. Crucially, the increased ACh levels promoted LUAD cell migration and invasion via modulation of the α5-nAChR/DNA methyltransferase 1 (DNMT1)/FHIT axis. In a chronic unpredictable stress (CUMS) mouse model, chronic stress promotes tumour development, accompanied by changes in α5-nAChR, DNMT1, FHIT, and vimentin. Together, these findings reveal a novel chronic stress-mediated LUAD signalling pathway: chronic stress enforces lung adenocarcinoma cell invasion and migration via the ACh/α5-nAChR/FHIT axis, which could be a potential therapeutic target for chronic stress-related LUAD.