IKZF3 promotes gastric cancer progression via Hedgehog signaling activation and is targetable by SANT-1

Abstract

Elevated expression of Aiolos family zinc finger 3 (IKZF3), a transcription factor crucial for lymphocyte maturation, is observed in hematological cancers. However, its role in gastric cancer (GC) remains unclear. We detect the increased IKZF3 levels in GC tissues using immunohistochemical, qRT-PCR and western blot analysis. The function of IKZF3 in GC cells is further studied through CCK-8, Transwell, colony formation, scratch wound healing, and flow cytometry assays. IKZF3 overexpression significantly promotes GC cell invasion, migration, and proliferation, whereas IKZF3 knockdown induces cell cycle arrest at the G1/S phase. Flow cytometry confirms these alterations in cell cycle dynamics. Using the JASPAR database, we determine that IKZF3 binds to the SMO promoter region, thereby activating SMO expression. Notably, the SMO inhibitor SANT-1 effectively reverses IKZF3-mediated effects. Furthermore, IKZF3 promotes GC tumor growth in xenograft models. Our findings highlight the pivotal role of IKZF3 in GC progression by modulating SMO expression and activating the Hedgehog signaling pathway. Therapeutically, targeting IKZF3 with SANT-1 is promising for mitigating GC proliferation and invasion. This study provides insights into potential therapeutic approaches targeting IKZF3 for GC treatment.

1. Introduction

Gastric cancer (GC) is a significant universal health issue in East Asian countries [1,2]. In 2020, GC was the third leading cause of cancer-associated death worldwide, with over 1 million new diagnoses and 768,000 deaths reported [3]. By 2021, 26,560 Americans had been diagnosed with GC, and 11,180 passed away from it, ranking it as the sixteen identified cancer and the seventeen leading causes of cancer-related mortality in the USA [4]. Although a small number of special medications have been produced, treating GC patients in the clinic remains extremely difficult because of their unknown fundamental pathogenic mechanisms [5]. To improve patient prognosis, a therapeutic strategy including potent molecular target medications should be considered [6].

The IKZF3 gene, located at 17q11.22, encodes the transcription factor Aiolos, a key regulator of lymphocyte development and immune function [7,8]. Aiolos, identified as a binding partner of IKAROS, is essential for B-cell proliferation and differentiation. The gene contains eight exons and seven introns. Lenalidomide (Len) targets Aiolos and IKAROS, inhibiting the transdifferentiation of innate lymphoid cell 3 (ILC3) cells to ILC1/NK cells, a process linked to elevated Aiolos expression [9]. Studies in mice lacking Aiolos have revealed its role in Th17 differentiation, B-cell activation, and NK cell maturation [10–12]. Aiolos also collaborates with IKAROS to regulate the expression of λ5, a component of pre-B-cell receptors [13,14].

Previous studies, by using an integrative approach, analyzed extensive datasets encompassing patient genomics, transcriptomics, and clinical information, which led to the identification of IKZF3 as a commonly amplified gene in breast cancer with HER2 overexpression [15,16]. Another study indicated a potential role of IKZF3 in the onset and progression of head and neck squamous cell carcinoma [17]. Furthermore, IKZF3 overexpression has been shown to predict a poor prognosis, particularly in intestinal-type GC. These findings suggest that IKZF3 plays a significant role in the occurrence, metastasis, and prognosis of several neoplasms and hematological malignancies. Therefore, we are interested in exploring the molecular mechanisms that underlie the role of IKZF3 in GC.