Decreased Expression of LAMB3 Is Associated with EsophagealCancer Stem Cell Formation

Esophageal squamous cell carcinoma (ESCC) is a highly aggressive cancer. The maincause of death in ESCC is related to relapse, metastasis, and resistance to cancer therapy. Recentstudies have shown that a minor subset of cancer cells, known as cancer stem cells (CSCs), areresponsible for tumor formation initiation and cancer progression. Understanding the genesassociated with CSCs and metastasis can help in targeted cancer therapy. The aim of this studywas to assess the expression of LAMB3 and TOP2A metastasis-associated genes in CSCs andadherent cells in the xenograft mouse model.

Esophageal CSCs were enriched by the sphere formation method. The expressionlevel of LAMB3 and TOP2A genes were evaluated in spheres and adherent cells in vitro byqRT-PCR. A xenograft mouse model was established to investigate the tumorigenesis andmetastasis potential by subcutaneous and tail vein injection of CSCs and adherent YM-1 cells.Consequently, LAMB3 and TOP2A expression at the mRNA level was assessed in tumors.Immunohistochemistry was also used to evaluate the LAMB3 expression at the protein levelin tumors.

CSCs-derived tumor was developed more quickly than the adherent cells-derivedtumor. LAMB3 at mRNA and protein level was significantly down-regulated in sphere-derivedtumor compared with adherent cells-derived tumor (P value <0.05). TOP2A expression wasalmost similar in both sphere cells and adherent cells and there was no significant difference.

we concluded that YM-1 spheres have CSCs characteristics in vitro with highcapability of tumorigenicity in vivo. Our results were also shown that the LAMB3 expressionwas decreased in YM-1 spheres suggesting LAMB3 association with sphere formation.