Gastric adenocarcinoma (STAD) exhibits extensive intratumoral heterogeneity that contributes to tumor progression and therapeutic resistance. In this study, we integrated single-cell RNA sequencing and bulk transcriptomic analyses to characterize malignant epithelial subtypes in STAD. Among seven identified tumor subtypes, the OLFM4-associated C3 subtype exhibited enriched palmitoylation-related signatures and altered metabolic activities, particularly glycolysis-related pathways. Functional enrichment analyses further supported the enrichment of multiple energy metabolism pathways. To evaluate the association between OLFM4 and metabolic regulation, recombinant OLFM4 treatment and siRNA-mediated OLFM4 knockdown were performed in gastric cancer cell lines. OLFM4 upregulation increased the expression of ZDHHC2 and GLUT1, accompanied by enhanced glucose uptake and elevated ATP production, whereas OLFM4 silencing reduced ZDHHC2 and GLUT1 expression. In addition, a prognostic risk model derived from C3 subtype-associated genes (MUC16, RALA, and PCBD1) effectively stratified STAD patients and was associated with immune checkpoint expression and immune infiltration. Collectively, our findings identify an OLFM4-associated gastric cancer cell state with palmitoylation-related signatures and altered metabolic activities, highlighting its potential relevance to metabolic heterogeneity in gastric adenocarcinoma.

Pancreatic tumors frequently exhibit calcification, suggesting potential osteogenic-related phenotypic plasticity. This study aimed to systematically evaluate whether pancreatic ductal adenocarcinoma (PDAC) cells acquire osteogenic-like features under induction conditions and to assess the associated phenotypic and molecular changes. PDAC cell lines and non-malignant pancreatic epithelial cells were subjected to osteogenic induction. Mineralization, alkaline phosphatase (ALP) activity, osteogenic marker expression, and malignant phenotypes were evaluated. RNA sequencing was performed at defined time points to characterize transcriptional changes. Pharmacological inhibition of MEK and siRNA-mediated knockdown of RUNX2 were applied to examine the involvement of MAPK–ERK signaling and downstream transcriptional regulation. Osteogenic induction led to calcium deposition and increased ALP activity in a subset of PDAC cell lines, accompanied by upregulation of osteogenic-associated markers, including RUNX2 and SPP1. Induced cells exhibited reduced migration, clonogenicity, invasion, and proliferation. Transcriptomic analysis revealed activation of osteogenesis-related and calcium-transport pathways, along with downregulation of cell cycle programs. MAPK–ERK signaling was activated during induction, and MEK inhibition attenuated RUNX2 and ALP expression as well as mineralization-associated changes. Furthermore, RUNX2 knockdown reduced ALP expression and mineralization levels, indicating its contribution to the osteogenic-like phenotype. PDAC cells can acquire osteogenic-like features under defined induction conditions, accompanied by coordinated transcriptional reprogramming and reduced malignant phenotypes. The observed mineralization-associated phenotypes may reflect a combination of active processes and passive calcium deposition. In addition, the MAPK–ERK–RUNX2 axis appears to be involved in this process, although it may reflect a broader adaptive or stress-associated reprogramming rather than lineage commitment. These findings provide insight into the potential relationship between tumor calcification and phenotypic plasticity in PDAC.

As a malignant tumor with high heterogeneity, gastric cancer (GC) still suffers a poor prognosis despite therapeutic advances. For further investigation of its heterogeneity, the single-cell RNA (scRNA) sequencing of human GC samples has been analyzed, which stratifies malignant epithelial cells into seven tumor subtypes. Among these seven subtypes, the C3 tumor subtype characterized by OLFM4 expression shows distinct biological features with enhanced palmitoylation and energetic metabolism, which presents the significant activation of related specific modules, including a palmitoyltransferase of protein palmitoylation, ZDHHC2, and an important transporter of glycolysis named GLUT1. Besides, the functional assays also confirm that the upregulation of expressed OLFM4 could enhance the ATP production in GC cell lines, which indicates elevated energetic metabolism. Moreover, three prognosis-associated genes (MUC16, RALA, PCBD1) are used to establish a prognostic risk model, which could effectively predict the survival of STAD patients and is correlated with the tumor microenvironment (TME) including not only immune checkpoint expression and infiltration of immune cells. These findings not only highlight OLFM4 as a defining biomarker of a metabolically active gastric cancer subtype but also indicate the possibility that targeting palmitoylation and energy metabolism may offer new therapeutic strategies for patients with OLFM4-high gastric tumors.