FANCA facilitates G1/S cell cycle advancement, proliferation, migration and invasion in gastric cancer

Abstract

The present study explores the function of FANCA gene, a pivotal member of the Fanconi anaemia (FA) pathway crucial for preserving genomic stability and preventing cancer, particularly in the context of gastric cancer (GC). Using immunohistochemistry, quantitative real-time PCR, and western blot analysis, we evaluate FANCA mRNA and protein expressions in GC cell lines. The relationship between FANCA expression and clinicopathological characteristics is also explored. Various assays, including CCK8, colony formation, wound healing, and Transwell assays, are used to assess functional changes in cells associated with FANCA. Flow cytometry is utilized to evaluate alterations in the cell cycle resulted from FANCA knockdown and overexpression. Our findings show elevated FANCA expression in GC cell lines, with levels correlated with pathologic stage and lymphatic metastasis. FANCA knockdown impedes cell proliferation, migration, and invasion and induces G1/S phase cell cycle arrest. Conversely, FANCA overexpression stimulates cell proliferation, migration, and invasion. In vivo xenograft experiments confirm the promotional role of FANCA in GC tumor progression. Moreover, FANCA overexpression is associated with the activation of cell cycle. Collectively, our results suggest that FANCA drives malignant cell behaviors in GC through the cell cycle pathway, highlighting its potential as a therapeutic target for the treatment of GC.

1. Introduction

Gastric cancer (GC), or stomach cancer, remains a challenging global health concern, demanding continued research and innovation for prevention, early detection, and treatment. This malignancy is associated with significant morbidity and mortality and ranks as the fifth most common cancer worldwide, with substantial regional variations in its incidence and outcomes [1,2]. Emerging research is shedding light on the complexities of GC, including its genetic and molecular underpinnings, paving the way for novel approaches to deal with this formidable disease. The global distribution of GC is marked by notable disparities, with a disproportionately higher burden in specific regions, such as Eastern Asia and parts of South America, and a lower incidence in North America and Western Europe [3]. These geographic differences reflect a convergence of genetic, environmental, and lifestyle factors that contribute to disease initiation and progression. The role of Helicobacter pylori infection, a well-established risk factor, continues to be a focal point in GC research, as does the impact of dietary habits, tobacco use, and familial predisposition [4]. Recent advances in molecular biology have illuminated the heterogeneity of gastric cancer, leading to the recognition of distinct subtypes that have different prognoses and therapeutic implications. The integration of genomics and precision medicine is shaping the development of targeted therapies and personalized treatment strategies for patients [5,6].

The FANCA gene is a vital component of the Fanconi anaemia (FA) pathway, a complex network of proteins responsible for mending DNA interstrand crosslinks (ICLs). These crosslinks arise when both strands of the DNA double helix are covalently linked, posing a significant threat to genomic stability. If left unrepaired, these crosslinks can lead to chromosomal abnormalities, cell death, and increased susceptibility to cancers [7]. Positioned on the long arm of chromosome 16 (16q24.3), the FANCA gene extends across a genomic region comprising multiple exons and introns. This gene encodes the FANCA protein, a large protein crucial to the FA core complex. This complex, consisting of various FA proteins, such as FANCB, FANCC, FANCE, FANCF, FANCG, FANCL, and others, is central to activating the FA pathway [8,9]. The role of FANCA involves the assembly and stability of this core complex. The core complex is essential for the monoubiquitination of the FANCD2 and FANCI proteins, a critical step in FA pathway activation. The activated FANCD2-FANCI complex plays a central role in coordinating the repair of DNA interstrand crosslinks [10]. Mutations in the FANCA gene can lead to FA, resulting in a non-functional or less stable FANCA protein. This disruption affects the formation of the FA core complex, impairing the repair of DNA interstrand crosslinks and contributing to the phenotypic manifestations of FA. [11]. Individuals with biallelic mutations in FANCA may exhibit various clinical features, including bone marrow failure, congenital anomalies (such as skeletal abnormalities), and an elevated risk of cancer.