Transforming growth factor-beta (TGF-beta) is a potent inhibitor of immune responses. Macrophage-derived products, including TGF-beta, have been suggested as inhibitors of the antitumor immune response. We hypothesized that IL-7, a cytokine with antitumor properties, may exert its immunoregulatory effects in part through the down-regulation of TGF-beta. To test this hypothesis we analyzed IL-2-...

Transforming growth factor beta (TGF-beta) is a multifunctional cytokine capable of regulating diverse cellular processes. In this study we investigated the effect of autocrine TGF-beta signaling on tumor necrosis factor (TNF) alpha-induced cell death. We abrogated the TGF-beta autocrine loop by overexpression of a truncated TGF-beta type II receptor in MCF-7 breast carcinoma cells and found th...

We report the results of a histochemical study, using polyclonal antipeptide antibodies to the different TGF beta isoforms, which demonstrates that retinoic acid regulates the expression of TGF beta 2 in the vitamin A-deficient rat. Basal expression of TGF beta 2 diminished under conditions of vitamin A deficiency. Treatment with retinoic acid caused a rapid and transient induction of TGF beta ...

Several observations correlate increased expression of transforming growth factor (TGF) beta 1 with tumorigenesis, suggesting that expression of this multifunctional growth factor may provide an advantage in tumor formation. However, many tumor cells are inhibited in their proliferation by TGF-beta in vitro, thus suggesting that TGF-beta synthesis could exert an antiproliferative effect on tumo...

Previous studies from this laboratory (Schroy, P., Rifkin, J., Coffey, R.J., Winawer, S., and Friedman, E. (Cancer Res., 50: 261-265, 1990; Schroy, P.C., Winawer, S., and Friedman, E. Cancer Lett., 48: 53-58, 1989) found that a 7-day treatment of the human colon carcinoma cell line HT29 with the differentiation agent hexamethylene bisacetamide (HMBA) induces both a 4-5-fold increase in transfor...

Biopsies from volunteers challenged with Cryptosporidium parvum were examined for transforming growth factor beta1 (TGF-beta1). None of the prechallenge biopsies exhibited TGF-beta. Seven of 12 volunteers with oocyst shedding expressed TGF-beta versus 2 of 13 volunteers without detected oocysts. The association of TGF-beta expression with oocyst excretion and the timing of symptoms suggests tha...

Transforming growth factor beta (TGF-beta) signaling via Smad proteins occurs in various cell types. However, whereas the biological response to TGF-beta can be as distinct as growth promoting (i.e., mesenchymal cells) versus growth inhibiting (i.e., epithelial cells), few discernible differences in TGF-beta signaling have been reported. In the current study, we examined the role of Ras in the ...

Although hematopoietic growth factors have been extensively studied as to their roles in recruitment of hematopoietic progenitors from quiescence state to cell division state, little is known of their effects on cell-cycling of progenitors that have already transited from quiescence into active cell-cycling. We examined the effects of the flt3 ligand (FL) on cell-cycling of hematopoietic progen...

BACKGROUND Growth arrest in many cell types is triggered by transforming growth factor beta (TGF-beta), which signals through two TGF-beta receptors (type I, TGF-beta RI, and type II, TGF-beta). In the signaling pathway, TGF-beta binds to the extracellular domain of TGF-betaRII, which can then transphosphorylate TGF-betaRI in its glycine/serine (GS)-rich box. Activated TGF-betaRI phosphorylates...

TGF-beta is a therapeutic target for renal fibrosis. Scientists have long sought ways to antagonize TGF-beta to ameliorate diabetic nephropathy. Bone morphogenetic protein (BMP-2) is a member of the TGF-beta superfamily and is highly regulated in the kidney. Thus, the role of BMP-2 was investigated in NRK-49F cells (rat fibroblasts). We showed that TGF-beta1 induces an increase in fibronectin. ...