Biology subjects

Camorlinga-Ponce, M.

Publications and source records attributed to Camorlinga-Ponce, M..

3 recordsLinked to original sources

bioRxiv2025

Determination of Copy Number Variations and Affected Gene Networks in Breast Cancer from Mexican Patients

Triple-negative breast cancer (TNBC) is an aggressive subtype with limited treatment options and high molecular heterogeneity. In this study, we performed a genome-wide analysis of copy number variations (CNVs) using high-density microarrays in tumor tissue (TUM), tumor adjacent tissue (ADJ), and leukocytes (LEU) from five Mexican TNBC patients. We identified both unique and shared CNVs across tissues, including alterations in key chromosomal regions such as 1q23.3, 1q32.1, and 8q24.3, which harbor oncogenes like MYC, MCL1, and BCL9. Losses in 6q25.2 affecting ESR1 were also detected. CNVs were enriched in genes related to the Hallmarks of Cancer, with TUM samples showing profiles associated with proliferation, metastasis, and immune evasion; ADJ samples with growth suppression; and LEU samples with genomic instability. Pathway enrichment analyses revealed disrupted functions in DNA repair, extracellular matrix organization, and TP53 signaling in TUM. Notably, EGFR, ERCC4, and HSP90AB1 emerged as central nodes in interaction networks and may serve as markers or therapeutic targets. This is the first CNV profiling study of its kind in TNBC from Mexican patients, highlighting the importance of including underrepresented populations in genomic research to uncover distinct molecular signatures and potential diagnostic or therapeutic avenues. ImplicationsMolecular signatures of breast cancer (BC), predicted bioinformatically, involve common and distinct CNV-Hallmarks of Cancer genes, which are suitable candidates for screening as potential BC markers.

genomics↗

bioRxiv2021

Copy number alterations and epithelial-mesenchymal transition genes in diffuse and intestinal gastric cancers in Mexican patients

Gastric cancer (GC) is a malignancy with the highest mortality among diseases of the digestive system worldwide. The study of GC-alterations is crucial to understand tumor biology, to establish important aspects of cancer prognosis and treatment response. Here, we purified DNA and performed whole-genome analysis with high-density arrays in samples from Mexican patients diagnosed with GC: diffuse (DGC) or intestinal (IGC), or non-atrophic gastritis (NAG) samples that served as controls. We identified shared and unique copy number alterations (CNA) between these altered tissues involving key genes and signaling pathways associated with cancer, allowing their molecular distinction and identification of the most relevant molecular functions impacted. When focused on epithelial-mesenchymal transition (EMT) genes, our bioinformatic analysis revealed that the altered network associated with chromosomal alterations included 11 genes shared between DGC, IGC, and NAG, as well as 19 DGC- and 7 IGC-exclusive genes, whose main molecular functions included adhesion, angiogenesis, migration, metastasis, morphogenesis, proliferation, and survival. This study presents the first whole-genome high-density array study in GC from Mexican patients and reveals shared and exclusive CNA-genes in DGC and IGC. In addition, we provide a bioinformatically predicted network focused on CNA-altered genes involved in the EMT, associated with the hallmarks of cancer, as well as precancerous alterations that could lead to gastric cancer. ImplicationsMolecular signatures of diffuse and intestinal GC, predicted bioinformatically, involve common and distinct CNA-EMT genes related to the hallmarks of cancer that are potential candidates for screening GC biomarkers, including early stages.

cancer biology↗

bioRxiv2019

cfrB,cfrC, and a potential new cfr-like gene in Clostridium difficile strains recovered across Latin America

Cfr is a radical S-adenosyl-L-methionine (SAM) enzyme that confers cross-resistance to all antibiotics targeting the large ribosomal subunit through hypermethylation of nucleotide A2503 of 23S rRNA. Of the four known cfr genes known to date, cfr(B) and cfr(C) have been sporadically found in C. difficile, yet functional characterization of cfr(C) is still lacking. We identified genes for putative Cfr-like enzymes among clinical C. difficile strains from Mexico, Honduras, Costa Rica, and Chile. To confirm their identity and activity, we obtained minimum inhibitory concentrations for ribosome-targeting antibiotics, annotated whole genome sequences, and performed a functional characterization of Cfr(C). The seven representative isolates analyzed displayed different levels of resistance to PhLOPSA antibiotics in the absence of the ribosome protection factor OptrA, and mutations in genes for 23S rRNAs or the ribosomal proteins L3 and L4. cfr(B) was detected in four isolates as part of a Tn6218-like transposon or an un-described mobile genetic element. In turn, cfr(C) was found integrated into an ICE-element. One isolate harbored a putative cfr-like gene that shows only 51-58% of sequence identity to Cfr and known Cfr-like enzymes. Moreover, our in vitro assays confirmed that Cfr(C) methylates E. coli and C. difficile 23S rRNA fragments. These results indicate selection of cfr-like genes in C. difficile from Latin America, suggest that the diversity of cfr-like resistance genes is larger than anticipated, and provide the first assessment of the methylation activity of Cfr(C).

microbiology↗