2nd Edition of Public Health World Conference (PHWC) 2026

Abstract

Objective: This study aims to elucidate the degradation mechanism of circ_FANCA in the malignant transformation of human bronchial epithelial cells induced by cadmium and to reveal its regulatory mechanism on the tricarboxylic acid (TCA) cycle, thereby providing new molecular targets and a theoretical basis for the prevention and early diagnosis of cadmium-related lung cancer.

Materials and Methods:

1. Screening of mutant genes and functional characterization. Genome-wide association analysis combined with Sanger sequencing was used to predict and validate the mutation sites of the POLN gene in malignantly transformed cells. By constructing overexpression plasmid vectors for POLN mutants, the role of POLN mutations in malignant transformation was determined using Transwell, EdU, soft agar colony formation, and nude mouse tumorigenesis assays.

2. Screening and functional validation of circRNA. High-throughput sequencing and qRT-PCR were employed to screen and validate the significantly downregulated circRNA—circ_FANCA. Its circular structure was confirmed by linear enzyme treatment and agarose gel electrophoresis. Interference and overexpression plasmid vectors for circ_FANCA were constructed, and combined with in vivo and in vitro functional experiments, the tumor-suppressive role of circ_FANCA in malignant transformation was established.

3. Elucidating the regulatory mechanism of POLN on circ_FANCA. Based on database analysis and me-RIP experiments, the specific m6A methylation modifications of POLN and circ_FANCA were predicted and validated. Dual-luciferase reporter gene and dot blot assays were used to demonstrate that POLN mediates the downregulation of circ_FANCA by enhancing m6A modification. Further rescue experiments clarified the specific mechanism by which POLN mutations mediate the degradation of circ_FANCA through the regulation of m6A modification, recognition by YTHDF2, and recruitment of the HRSP12-POP1 complex.

4. Investigating the regulatory mechanism of circ_FANCA in cadmium-induced malignant transformation. Bioinformatics analysis was used to screen the downstream signaling pathways of circ_FANCA. RNA pull-down and western blot experiments were employed to validate the interaction between circ_FANCA and its downstream target protein MYC. Combined with molecular biology experiments, its regulatory network was clarified, systematically revealing the functional mechanism of circ_FANCA in cadmium-induced malignant transformation.

Results:

1. Mutant POLN recruits YTHDF2 and enhances m6A methylation modification;

2. The YTHDF2-HRSP12-POP1 complex specifically degrades m6A-modified circ_FANCA;

3. Circ_FANCA regulates the upregulation of MYC, activates TCA cycle enzymes (ACLY/ASCT2), and drives metabolic reprogramming and malignant transformation.

Conclusion: This study is the first to reveal that cadmium exposure induces POLN mutations, which mediate the degradation of circ_FANCA via the "m6A/YTHDF2-HRSP12-POP1" axis, thereby activating the TCA cycle to promote metabolic reprogramming and malignant transformation. This discovery not only deepens the understanding of the epigenetic regulatory mechanisms of environmental carcinogens but also provides an important theoretical basis for the targeted therapy of cadmium-related cancers and public health risk prevention and control.