ANNOUNCEMENTS
The complexity and heterogeneity of cancer cells make it a challenging disease to study and treat. Three-dimensional spheroid models have been shown to closely mimic the cellular and molecular features of solid tumours, making them a valuable tool for cancer research. Despite significant investments in cancer research and drug discovery, there is still a need for more effective therapies that can target the genetic heterogeneity and the mechanisms of resistance. The heterogeneity of gastric cancer poses significant challenges for the diagnosis and treatment of the disease. In the present study the 3D spheroid models derived from two cells of AGS cells, provide a physiologically relevant model for studying functional heterogeneity of gastric cancer. Further identification of hyper and hypo proliferative clonal spheroids has provided a new model to capture the functional heterogeneity. The comparative transcriptome analysis of hypo and hyper proliferative clonal spheroids indicates two genetically distinct population with distinct phenotype.
Further, TCGA data set analysis for expression of signature genes suggests a convolution of differentially upregulated and down regulated genes of hypoproliferative clonal spheroids. 42 genes of 100 upregulated genes of hypoproliferative clonal spheroids showed a cumulative increase in gastric cancer tissues whereas 38 genes out of 107 downregulated genes showed downregulation in gastric cancer tissues. Importantly the H2AFZ gene enriched in upregulated pathways also showed increase in gastric cancer tissue compared to normal tissues and higher expression of those genes showed an worst survival in the gastric cancer patients. Same analysis was observed with DUSP1, FOS, and MAPK10 genes enriched in downregulated pathways have lower expression in gastric tissues. Lower expressions of these genes were associated with worse survival of the patients. Further to confirm that hyper and hypo clonal spheroids represent a true functional heterogeneity of gastric cancer cell lines, we treated spheroids with arsenic and curcumin. Arsenic disulfide causes migration of cells only from hypoproliferative clonal spheroids, whereas curcumin only effected the growth of hyperproliferative clonal spheroids. Also, failure of nonoxidisable curcumin in inhibiting the growth of hyperproliferative clonal spheroids highlighted fact that oxidized product may be playing a critical role in inhibition of growth.
In summary this study establishes the presence of functionally distinct clonal cell population in gastric cancer. These functionally distinct clonal spheroids can be used as a model to study proliferation/growth of spheroids and migration of cells from spheroids and ultimately in drug discovery.
