Antisense oligonucleotides specific for transforming growth factor beta2 inhibit the growth of malignant mesothelioma both in vitro and in vivo.

Transforming growth factor beta (TGF-beta) is a potent growth-regulatory and immunomodulatory cytokine that exerts a diverse range of effects on many types of cells. High levels of TGF-beta are produced by several human and mouse malignant mesothelioma (MM) cell lines, and it is known to act as a growth factor for these cells. Antisense oligonucleotides (ODNs), targeted against specific TGF-beta mRNA, were used to block TGF-beta production from MM cells in vitro and in vivo. TGF-beta antisense ODNs were encapsulated in liposomes and transfected into MM cells or delivered intratumorally. TGF-beta2 mRNA levels, assessed by semiquantitative PCR, and TGF-beta2 protein secretion were reduced after TGF-beta2 antisense ODN transfection. MM cell proliferation, assessed by tritiated thymidine uptake, was specifically inhibited by both TGF-beta1- and TGF-beta2-specific antisense ODNs. In vivo administration of TGF-beta2 antisense ODNs, delivered locally, reduced tumor growth. These data show that the blockade of TGF-beta2 within this tumor reduces tumor growth and raises the possibility that TGF-beta2 antisense ODNs may be useful as a therapy for this disease.