Low E-cadherin and beta-catenin expression correlates with increased spontaneous and artificial lung metastases of...

This study examined the relationship between the expression of E-cadherin or beta-catenin in murine adenocarcinomas and their hematogenous metastatic propensity, assessed by both spontaneous and artificial lung metastasis. Seven different carcinomas, syngeneic to C3Hf/Kam mice were used: 4 mammary carcinomas (MCa-4, MCa-29, MCa-35, and MCa-K), ovarian carcinoma OCa-I, hepatocarcinoma HCa-I, and adenosquamous carcinoma ACa-SG. These tumors vary widely in their ability to spontaneously metastasize to the lung (from 0 to 100% metastatic incidence), and their cells greatly differ in their ability to form artificial lung nodules when injected i.v. Primary tumors in the leg were assessed for E-cadherin and beta-catenin expression by western blotting. The expression of both proteins showed wide variation among the tumors; however, the expression of E-cadherin correlated well with that of beta-catenin. There was significant inverse correlation between the expression of E-cadherin, as well as beta-catenin, and the incidence of both spontaneous and artificial lung metastases from these tumors. Spontaneous metastases of highly metastatic HCa-I and moderately metastatic MCa-35 were significantly lower in E-cadherin and beta-catenin expression than their corresponding primary tumors were. Thus, the propensity of murine carcinomas for hematogenous spread is highly related to E-cadherin and beta-catenin levels in primary tumors. The inverse correlation between the expression of these molecules and spontaneous and artificial metastases implies that tumor cells with low E-cadherin and beta-catenin content have increased ability to enter the vascular circulation at the primary tumor site and to colonize distant tissues.