Stress-Survival Pathway Profiling Reveals MCM10 as a Candidate Biomarker of Hispanic Colorectal Cancer Disparities

Colorectal cancer (CRC) remains the second leading cause of cancer mortality in the U.S., with significant racial and ethnic disparities in incidence, survival, and mortality rates. The rising incidence of early-onset CRC and the frequent presentation at advanced stages of CRC among the Hispanics makes this an important ethnic group to study. A deeper understanding of the complex interplay between molecular, genetic, and environmental factors is critical for developing targeted therapies to reduce the prevalence in specific racial and ethnic groups, such as Hispanics. This study explores the role of stress-survival pathway (SSP) genes in early-onset and late-stage CRC, primarily focusing on disparities between Hispanics and Non-Hispanic Whites (NHWs). Additionally, this study investigates the role of MCM10, in contributing to CRC disparities among the Hispanic populations with an emphasis of early-onset and late-stage CRC Hispanics.

One of our previous studies had identified some SSP protein coding genes associated with CRC. The transcript and protein level expressions of these genes were validated in CRC cell lines, cDNA arrays, and tissue microarrays, using qRT-PCR and immunohistochemistry, respectively. The transcript level expressions of differentially expressed SSP genes were further evaluated in Hispanic and NHWs tumor tissues, including early onset and late-stage cohorts. Additionally, we performed cellular, physiological, and functional assays to explore the role of MCM10 in tumor progression, before and after siRNA mediated knockdown of MCM10. High-throughput transcriptomic and proteomic analyses were performed to reveal the underlying molecular mechanism.

We observed the differential expressions of twelve SSP genes in CRC cell lines, at the transcript level; that of ten genes in early and late stages using cDNA arrays, and nine genes at the protein levels using tissue microarrays and immunohistochemistry. Hispanic CRC samples showed differential expression of all nine SSP genes compared to NHWs, in early-onset, and late-stage CRC, with all genes being upregulated other than CDK4 and PRDX4 in late-stage CRC and CDK4 in early-onset CRC. Our functional study demonstrated that MCM10 knockdown in CRC cell lines significantly reduced cell proliferation, growth, invasion, and migration by inducing cell cycle arrest, apoptosis, and reactive oxygen species pathways. The integrative RNA-sequencing and proteomics study identified that PPFIA1 could be associated with MCM10 mediated cancer progression. The role of MCM10 and PPFIA1 in cancer progression has also been validated by CRISPR-Cas9 mediated MCM10 knock out, using a Hispanic CRC patient derived organoid.

The differential expression of SSP genes suggest a potential molecular contribution to CRC disparities in the Hispanic population. The essential oncogenic role of MCM10 and its axis with PPFIA1 was identified; this could lead to a new avenue for therapeutics targeting the MCM10-PPFIA1 axis, thereby, combating early-onset and advanced-stage CRC in this high-risk ethnic group.