Acta Biochimica et Biophysica Sinica•2026•DOI: 10.3724/abbs.2025118
Cervical cancer represents a significant global health concern affecting women. The global cancer burden data published by the World Health Organization’s International Agency for Research on Cancer (IARC) indicated that the incidence and mortality of cervical cancer were the fourth most common malignancy in females worldwide in 2022 [1]. DNA methylation is recognized as a pivotal epigenetic mechanism for gene silencing, which may accumulate with disease severity [2]. Hypermethylation has been discovered in several tumor suppressor gene (TSG) promoters in human cancers, and further understanding of gene silencing mechanisms has led more studies to consider epigenetic disruption as an important mechanism leading to the silencing of tumor suppressor genes in tumor development [3]. Recent studies have reported that methylation of the zinc finger protein 154 (ZNF154) gene plays an oncogenic role in the development of several cancers [4]. ZNF154 has been shown to inhibit tumor cell proliferation in nasopharyngeal carcinoma by altering the expression of E-cadherin through the Wnt/β-catenin pathway, thereby inhibiting epithelial-to-mesenchymal transition (EMT) [5]. He et al. [6] demonstrated that ZNF154 could transcriptionally regulate the expressions of tumor suppressor genes involved in the cell cycle, the p53 signaling pathway, and the Wnt/β-catenin signaling pathway in esophageal squamous cell carcinoma. Thus, ZNF154 can be considered a novel cancer biomarker of clinical significance. However, the role of ZNF154 in cervical cancer remains unclear. In the present study, we analyzed ZNF154 expression and its potential biological functions and molecular mechanisms in cervical cancer. ZNF154 was found to be downregulated by promoter methylation in cervical cancer tissue. Its overexpression in cervical cancer cells inhibited cell proliferation and migration. Mechanistically, ZNF154 inhibits the Wnt/β-catenin signaling pathway by directly targeting and positively modulating Nemo-like kinase (NLK) activity. Collectively, our findings indicate the crucial role of ZNF154 in the proliferation and migration of cervical cancer cells, indicating that ZNF154 may serve as a promising target for future therapeutic development.
Acta Biochimica et Biophysica Sinica•2025•DOI: 10.3724/abbs.2025053
Krüppel-like factors (KLFs) are a family of 18 transcriptional regulators characterized by three highly conserved C2H2 zinc fingers at their C-terminal regions. KLF7, a member of this family, plays a crucial role in cell proliferation, differentiation, and the development of the nervous system, adipogenesis, diabetes, and various cancers. Studies have shown that KLF7 aggravates metabolic disorders by impeding insulin secretion and sensitivity. The nuclear factor kappa-B (NF-κB) signaling cascade is essential for inflammatory responses, while fatty acid β-oxidation is vital for metabolism. Both are linked to insulin resistance, obesity, and cardiovascular diseases. A functional link between KLF7 and the NF-κB signaling pathway has been demonstrated. In rheumatoid arthritis, KLF7 activates NF-κB signaling pathway, leading to increased cell proliferation and the production of proinflammatory cytokines, including interleukin 6 (IL-6), IL-1β, and IL-17A. In adipose tissue, KLF7 may initiate NF-κB signaling pathway by upregulating protein kinase Cζ, causing significant IL-6 secretion. KLF7 also reduces oleate-induced lipid droplets in chicken preadipocytes, indicating its role in fatty acid metabolism. Studies in mice showed that KLF7 regulates the transcription of genes of the rate-limiting glycolytic enzyme phosphofructokinase liver type (PFKL) and the fatty acid β-oxidation enzyme acyl-CoA dehydrogenase long-chain (ACADL) in cardiomyocytes independently of peroxisome proliferator-activated receptor (PPAR) γ, thereby altering heart metabolism. Additionally, KLF7 may promote cervical cancer progression by enhancing fatty acid utilization efficiency at least via ACADL upregulation. Overall, KLF7 is crucial for the regulation of fatty acid β-oxidation. KLF7 is a ring-shaped protein with zinc fingers forming the protruding part of ring surface. The lack of the third zinc finger domain in KLF7 affected its function in chicken preadipocytes. However, the importance of zinc finger domains for the regulatory function of human KLF7 remains unclear. In this study, we engineered an overexpression vector for wild-type KLF7 (pCMV-myc-KLF7_WT) and three vectors for KLF7 mutants with different zinc finger deletions (pCMV-myc-KLF7_D1, pCMV-myc-KLF7_D2, and pCMV-myc-KLF7_D3). These vectors were constructed using primers shown in Supplementary Table S1 and cDNA from HEK293T cells. Western blot analysis in the HEK293T, Ishikawa, HeLa, and EC109 cells (Pricella, Wuhan, China) showed that, unlike cells transfected with the empty vector (EV) of pCMV-myc (Clontech, Mountain View, USA), Myc-tagged proteins appeared at expected sizes in cells transfected with either the wild-type KLF7 or any of the three mutant KLF7 overexpression plasmids after 48 h (Figure 1A and Supplementary Figure S1). The impacts of overexpressing various KLF7 isoforms on gene transcription related to the NF-κB signaling pathway and fatty acid β-oxidation were evaluated using luciferase reporter assays, real-time PCR, and western blot analysis in Ishikawa, HeLa, and EC109 cells 48 h post-transfection. Details of the luciferase reporter assay transfection protocol are provided in Supplementary Table S2, the oligonucleotide sequences for real-time PCR are shown in Supplementary Table S3, and the antibodies for western blot analysis are listed in Supplementary Table S4. Compared to EV group, wild-type KLF7 overexpression significantly boosted NF-κB pathway activity in HeLa and EC109 cells (P < 0.05, Figure 1B). Furthermore, wild-type KLF7 overexpression significantly elevated IL-6 and TNF-α expressions in Ishikawa and HeLa cells (P < 0.05, Figure 1C), confirming previous findings that KLF7 enhances inflammation via the NF-κB pathway [4,5]. Cells transfected with KLF7 overexpression plasmids lacking zinc fingers showed significant differences in NF-κB pathway activities compared to those transfected with the wild-type KLF7 overexpression plasmid (P < 0.05, Figure 1B). In HeLa and EC109 cells, the absence of zinc fingers reduced NF-κB signaling activity, with the reduction proportional to the number of zinc fingers lost (P < 0.05, Figure 1B). In Ishikawa cells, losing one or two zinc fingers increased NF-κB activity compared to the wild-type KLF7 (P < 0.05, Figure 1B). Additionally, the ability of KLF7 overexpression to increase IL-6 and TNF-α expression decreased with the loss of zinc fingers.
Acta Biochimica et Biophysica Sinica•2025•DOI: 10.3724/abbs.2024212
It is unclear what part KLF7 plays in cervical cancer. In this study, immunohistochemical and bioinformatics analyses reveal that KLF7 expression is lower in normal cervical tissues than in cervical cancer tissues, and the high level of KLF7 transcripts in cervical cancer tissues is negatively correlated with patients’ overall and disease-free survival. In addition, KLF7 overexpression facilitates the proliferation, migration, and invasion of cervical cells, reduces PFKL expression, and increases the expressions of KLF4, Nanog, OCT4, CD44, SOX2, and ACADL. Additionally, knocking out the Exon 2 of KLF7 in HeLa cells results in a decrease in the total expression of KLF7 but an increase in the nuclear expression of KLF7, an increase in the capacity for proliferation, migration, invasion, and oncogenicity, and an increase in the density and ridge density of mitochondria. Consistent with these findings, RNA-seq analysis shows that knocking out the Exon 2 of KLF7 facilitates the expression of gene sets associated with cancer compared with that in wild-type HeLa cells. Moreover, the administration of alpha-lipoic acid (ALA) leads to a reduction in KLF7 expression in cells and tumor tissues, a suppression of the proliferation, migration, and invasion of HeLa and SiHa cells, and an increase in the carcinogenic potential of HeLa cells, while KLF7 overexpression shows the opposite effect on the expressions of ACADL and PFKL in HeLa and SiHa cells. In conclusion, KLF7 promotes the development of cervical cancer, and ALA can downregulate KLF7 expression and play a positive role in cervical cancer treatment.
Acta Biochimica et Biophysica Sinica•2025•DOI: 10.3724/abbs.2025053
Krüppel-like factor 7 (KLF7) is a C2H2 zinc-finger transcriptional regulator implicated in insulin resistance, inflammation, and fatty acid metabolism. The functional necessity of its three zinc fingers for human KLF7 activity remained undefined. We engineered pCMV-myc-KLF7_WT and three zinc-finger deletion mutants (D1, D2, D3) and expressed them in HEK293T, Ishikawa, HeLa, and EC109 cells. Western blot confirmed expected Myc-tagged protein sizes at 48 h. Luciferase reporter assays showed that wild-type KLF7 significantly increased NF-κB activity (P < 0.05) and the promoter activities of ACADL, ECH1, and HADHB (P < 0.05) across all three cell lines, whereas deletion of any single zinc finger abolished these effects (P < 0.05). KLF7 did not alter NFKB1 mRNA (P > 0.05) or RelA (P65) protein levels, indicating downstream action within the NF-κB cascade. For fatty acid β-oxidation, wild-type KLF7 elevated CPT1A, ACADL, and ECH1 promoter activities and protein expression, with ACTB as internal control; zinc-finger-deficient mutants failed to sustain these transcriptional and translational increases. These data establish that the zinc-finger domain is indispensable for KLF7-mediated enhancement of NF-κB signaling and fatty acid β-oxidation gene transcription in human cells, providing a mechanistic basis for targeting KLF7 zinc fingers in metabolic and inflammatory disorders.