Kruppel-like factor 13 inhibits cell proliferation of gastric cancer by inducing autophagic degradation of β-catenin

F-box/WD Repeat-Containing Protein 5 Promotes Breast Cancer Progression by Regulating Ferroptosis via Enhancing Krüppel-like Factor 13 Ubiquitination Through Phosphoinositide 3-Kinase/Serine/Threonine Protein Kinase Pathway

Breast cancer (BC) is a prevalent malignancy among women. Evidence has indicated that F-box/WD repeat-containing protein 5 (FBXW5) is crucial in oncogenesis and progression. However, the function of FBXW5 in BC remains elusive. This work aims to explore the regulatory mechanisms of FBXW5 in the development of BC. The expression of FBXW5 in pan-cancer and breast invasive carcinoma (BRCA) was analyzed using The Cancer Genome Atlas (TCGA) database. FBXW5 level was enhanced in BC tissues. Besides, FBXW5 inhibition significantly decreased cell viability by 49.05% in MDA-MB-231 cells and 62.30% in MCF-7 cells. FBXW5 inhibition significantly inhibited cell proliferation by 66% in MDA-MB-231 cells and 74% in MCF-7 cells. FBXW5 inhibition significantly suppressed cell migration by 77.2% in MDA-MB-231 cells and 82.15% in MCF-7 cells. FBXW5 inhibition significantly inhibited cell invasion by 64.14% in MDA-MB-231 cells and 71.33% in MCF-7 cells. In vivo, FBXW5 depletion reduced tumor weight by 63.39% and tumor volume by 65.17%. Moreover, FBXW5 silencing restrained lung metastases in vivo. Besides, the impact of FBXW5 on the malignant behavior of BC cells was mediated through the regulation of ferroptosis. Mechanically, FBXW5 facilitated Kruppel-like factor 13 (KLF13) degradation by enhancing its ubiquitination. The addition of FBXW5 facilitated cell proliferation, migration, and invasion and inhibited ferroptosis in MDA-MB-231 and MCF-7 cells, which were neutralized by KLF13 overexpression. Besides, the knockdown of KLF13 led to the activation of the PI3K/AKT pathway. KLF13 silencing counteracted the inhibitory effects of FBXW5 depletion on cell proliferation, migration, and invasion, as well as its promotion of ferroptosis, effects that were reversed by LY294002. In conclusion, targeting FBXW5 may serve as a potential therapeutic strategy for BC by modulating the KLF13/PI3K/AKT axis.

METTL3-Dependent YTHDF2 Mediates TSC1 Expression to Regulate Alveolar Epithelial Mesenchymal Transition and Promote Idiopathic Pulmonary Fibrosis

Diffuse, progressive interstitial lung disease with few treatment options and low survival rates is known as idiopathic pulmonary fibrosis (IPF). Alveolar epithelial cell damage and dysfunction are the main features of IPF. TSC1 has been documented to exert a pivotal function in governing cellular growth, proliferation, and ontogenesis. This work investigated TSC1's function and mechanism in IPF. Mice were given BLM to cause pulmonary fibrosis, and A549 cells underwent epithelial mesenchymal transition (EMT) in response to TGF-β1. According to the data, TSC1 expression was reduced in IPF. Overexpression of TSC1 was established by adenopathy-associated virus in vivo and adenovirus in vitro to significantly block the EMT process. Besides, the findings from the RNA-sequencing analysis indicate that overexpression of TSC1 mitigated the EMT process by suppressing the activation of the AKT/mTOR pathway via downregulation of ACTN4 expression. To examine the upstream regulatory mechanism, we employed the SRAMP database to predict m6A modification of TSC1 mRNA, followed by verification of m6A modification levels and expression using MERIP-qPCR, Dot blot, RT-qPCR, and WB. The results indicated a high degree of m6A modification in TSC1 mRNA in pulmonary fibrosis. The expression of METTL3 was further found to be significantly elevated. METTL3 knockdown impeded EMT progression. METTL3 inhibits TSC1 expression by increasing TSC1 m6A modification through the reading protein YTHDF2. In conclusion, our study elucidated that the METTL3/YTHDF2/TSC1 signaling axis activates the AKT/mTOR pathway to promote the development of IPF. This study provides potential molecular-level therapeutic targets for IPF disease.

Bioinformatic Evaluation of KLF13 Genetic Variant: Implications for Neurodevelopmental and Psychiatric Symptoms

The Krüppel-like factor (KLF) family represents a group of transcription factors (TFs) performing different biological processes that are crucial for proper neuronal function, including neuronal development, synaptic plasticity, and neuronal survival. As reported, genetic variants within the KLF family have been associated with a wide spectrum of neurodevelopmental and psychiatric symptoms. In a patient exhibiting attention deficit hyperactivity disorder (ADHD) combined with both neurodevelopmental and psychiatric symptoms, whole-exome sequencing (WES) analysis revealed a de novo heterozygous variant within the Krüppel-like factor 13 (KLF13) gene, which belongs to the KLF family and regulates axonal growth, development, and regeneration in mice. Moreover, in silico analyses pertaining to the likely pathogenic significance of the variant and the impact of the mutation on the KLF13 protein structure suggested a potential deleterious effect. In fact, the variant was localized in correspondence to the starting residue of the N-terminal domain of KLF13, essential for protein-protein interactions, DNA binding, and transcriptional activation or repression. This study aims to highlight the potential involvement of the KLF13 gene in neurodevelopmental and psychiatric disorders. Nevertheless, we cannot rule out that excluded variants, those undetectable by WES, or the polygenic risk may have contributed to the patient's phenotype given ADHD's high polygenic risk. However, further functional studies are required to validate its potential contribution to these disorders.

Krüppel-like Factor-9 and Krüppel-like Factor-13: Highly Related, Multi-Functional, Transcriptional Repressors and Activators of Oncogenesis

Specificity Proteins/Krüppel-like Factors (SP/KLF family) are a conserved family of transcriptional regulators. These proteins share three highly conserved, contiguous zinc fingers in their carboxy-terminus, requisite for binding to cis elements in DNA. Each SP/KLF protein has unique primary sequence within its amino-terminal and carboxy-terminal regions, and it is these regions which interact with co-activators, co-repressors, and chromatin-modifying proteins to support the transcriptional activation and repression of target genes. Krüppel-like Factor 9 (KLF9) and Krüppel-like Factor 13 (KLF13) are two of the smallest members of the SP/KLF family, are paralogous, emerged early in metazoan evolution, and are highly conserved. Paradoxically, while most similar in primary sequence, KLF9 and KLF13 display many distinct roles in target cells. In this article, we summarize the work that has identified the roles of KLF9 (and to a lesser degree KLF13) in tumor suppression or promotion via unique effects on differentiation, pro- and anti-inflammatory pathways, oxidative stress, and tumor immune cell infiltration. We also highlight the great diversity of miRNAs, lncRNAs, and circular RNAs which provide mechanisms for the ubiquitous tumor-specific suppression of KLF9 mRNA and protein. Elucidation of KLF9 and KLF13 in cancer biology is likely to provide new inroads to the understanding of oncogenesis and its prevention and treatments.