Gene therapy of murine teratocarcinoma: separate functions for insulin-like growth factors I and II in immunogenicity and differentiation.

Abstract

Teratocarcinoma is a germ-line carcinoma giving rise to an embryoid tumor with structures derived from the three embryonic layers: mesoderm, endoderm, and ectoderm. Teratocarcinoma is widely used as an in vitro model system to study regulation of cell determination and differentiation during mammalian embryogenesis. Murine embryonic carcinoma (EC) PCC3 cells express insulin-like growth factor I (IGF-I) and its receptor, while all derivative tumor structures express IGF-I and IGF-II and their receptors. Therefore the system lends itself to dissect the role of these two growth factors during EC differentiation. With an episomal antisense strategy, we defme a role for IGF-I in tumorigenicity and evasion of immune surveillance. Antisense IGF-I EC transfectants are shown to elicit a curative anti-tumor immune response with tumor regression at distal sites. In contrast, IGF-II is shown to drive determination and differentiation in EC cells. Since IGF-I and IGF-U bind to type I receptor and antisense sequence used for IGF-II cannot form duplex with endogenous IGF-I tran-

Enhancement of immunogenicity of tumor cells by cotransfection with genes encoding antisense insulin-like growth factor-1 and B7.1 molecules

“…In addition, this treatment abolished tumorigenicity in syngeneic animals. [5][6][7][8][9][10][11][12] Immunization with the IGF-1 antisense transfectants elicited effective antitumoral immune responses that were both preventive and curative. 7,8 More recently, similar results have been reported by several groups, demonstrating that blockage of IGF-1 receptor with an antisense approach could convert tumor cells to an immunogenic phenotype.…”

“…Our results further support those obtained in studies of glioblastoma, melanoma, and hepatoma, which indicated that tumor cells transfected either with the IGF-1 antisense or with the B7 gene can directly stimulate naive T cells without the participation of CD4 ϩ T cells. 6,8,14,17 The tumor-specific antitumoral immunity can be adoptively transferred into naive animals by i.v. injection of CTLs generated either in vitro or in vivo.…”

“…[5][6][7][8] Ab specific for IGF-1 was purchased from KabiGen (Stockholm, Sweden) and used at a 1/500 dilution. For detection of the expression of MHC and adhesion molecules on the transfectants that have a potential to costimulate host immune responses, the cells were washed with phosphate-buffered saline and stained with rat monoclonal Abs (mAbs) to mouse MHC class I (M1/42), MHC class II (M5/114), B7.1 (4H12), intracellular adhesion molecule-1 (ICAM-1) (HA58), ICAM-2 (3C4), vascular cell adhesion molecule-1 (51-10C9) (PharMingen, San Diego, Calif), and CD44 (KM81) (ATCC).…”

The Role of the C Terminus and Na+/H+ Exchanger Regulatory Factor in the Functional Expression of Cystic Fibrosis Transmembrane Conductance Regulator in Nonpolarized Cells and Epithelia

“…All mutants were sequence-verified. To express CFTR in PANC-1 epithelia, WT and ⌬6 CFTR were subcloned into the pMT/EP episomal expression cassette, provided by Dr. J. Ilan (37). CFTR-GFP fusion was constructed by shuttling the HpaI/SalI fragment of the pEGFP-N3 vector (BD Biosciences) into pNUT-CFTR-HAC t after eliminating the hemagglutinin (HA) tag.…”

True

“…Firstly, overexpression of Akt inhibits apoptosis induced by various stimuli (Yuan et al, 2000). Secondly, treatment of tumour with antibody or anti-sense oligonucleotides targeting IGF-1R could decrease Akt protein expression and sensitize cells to drug-or irradiated-induced programmed cell death (Trojan et al, 1994;Shevelev et al, 1997;and Scotlandi et al, 1998). Finally, our results from kinetics experiments showed that the levels and tyrosine activity of Akt1 were decreased before MCF-7 apoptotic cell death induced the by IGF-1 inhibitor.…”