Transforming growth factor-beta in GI neoplasia, wound healing and immune response

Recurrent Intramucosal Gastric Carcinoma with Extensive Invasion to Duodenal Mucosa after Endoscopic Mucosal Resection: A Case Report

The occurrence of early gastric carcinoma with invasion to the duodenum is supposed to be very low, although advanced cancers arising in the antrum can often invade the duodenal area. Generally, malignant invasion of the duodenum is difficult to diagnose preoperatively, as spread of gastric cancer to the duodenum is often infiltrative and invades through the submucosal or subserosal layer. We report an unusual case of an intramucosal gastric carcinoma with extensive duodenal invasion that was preoperatively diagnosed by endoscopy.

Transforming growth factor-beta promotes 'death by neglect' in post-activated human T cells

Transforming growth factor-beta (TGF-beta) is central to the wound repair processes that follow local trauma and inflammation. In order to mimic the early events of wound-healing, we studied the effects of TGF-beta on mitogen-stimulated peripheral blood cells. TGF-beta added at the initiation of mitogenesis did not significantly alter T-cell activation, proliferation, CD45 isoform switching, or activation-induced cell death. By contrast, TGF-beta added 72 hr post-activation (or later) enhanced the cumulative increase in apoptotic T cells. TGF-beta had no effect on mitogen-induced up-regulation of Fas (CD95) or Fas ligand and did not enhance killing of the Fas-sensitive Jurkat cell line by activated T cells. Furthermore, TGF-beta had no direct effect on levels of mRNA for members of the bcl family (bcl-X, bfl-1, bik, bak, bax, bcl-2 and mcl-1). These findings suggest that TGF-beta does not directly induce apoptosis via the Fas system or by direct effects on bcl proteins. However, interleukin-2, which can 'rescue' lymphocytes from spontaneous apoptosis due to cytokine deprivation, abolished the pro-apoptotic effects of TGF-beta on post-activated T cells, thus demonstrating that TGF-beta increases the cytokine-dependence of T cells for survival. We propose a novel role for TGF-beta in the suppression of inflammation by promoting the elimination of post-activated T cells once the initiating stimulus has been resolved.

Plasma transforming growth factor beta1 in breast cancer patients treated with CMF chemotherapy

BACKGROUND

In early breast cancer patients the transformed epithelial cells are thought to be sensitive to transforming growth factor beta1 (TGFbeta1)-mediated growth arrest. TGFbeta1 may therefore act as an anti-tumour promoter. However, in advanced breast cancer resistance to such TGFbeta1 action develops. Neoplastic cells produce TGFbeta1, which may enhance tumour invasion and metastasis, mainly by intensifying angiogenesis, which is an immunosuppressive action. In the light of the potential role of TGFbeta1 in breast cancer pathogenesis, an understanding of the effect of applied therapeutic methods on plasma TGFbeta1 concentration is essential.

OBJECTIVE

To investigate the effect of adjuvant chemotherapy on plasma transforming growth factor beta1 (TGFbeta1) concentration in breast cancer patients with metastases to axillary lymph nodes.

METHOD

Fifteen stage II breast cancer patients on adjuvant chemotherapy with cyclophosphamide, methotrexate and 5-fluorouracil (CMF) were studied along with 15 healthy premenopausal women.

RESULTS

Plasma TGFbeta1 concentration (determined by the ELISA method) in the breast cancer patients did not differ significantly from that of the healthy women. Adjuvant CMF chemotherapy significantly decreased plasma TGFbeta1 concentration in those pre-menopausal breast cancer women with metastases to axillary lymph nodes.

CONCLUSION

The possible pathogenic action of this growth factor in stage II breast cancer disease warrants further investigation to elucidate whether the induced decrease of blood TGFbeta1 concentration is essential to successful chemotherapy.

The future of recombinant growth factors in wound healing

For more than a decade, clinical trials have been conducted of the application of topical exogenous recombinant growth factors in attempts to accelerate the healing of chronic wounds. Although the results of some of these trials have been encouraging, overall the results have been somewhat discouraging. Much of the difficulty lies in the paucity of carefully controlled clinical trials of wound healing. Since wound healing is a complex process that can be influenced, both positively and negatively, by many factors, designing these trials has proved difficult. To date, only a single recombinant growth factor-recombinant human platelet-derived growth factor-BB (rhPDGF-BB)- has been approved by the US Food and Drug Administration; and that only for use in diabetic foot ulcers. It is unlikely, however, that a single growth factor will be able to resolve all issues of repair or strengthen all vulnerabilities of chronic wounds. Our expectation, therefore, is that growth factors, cytokines, and other biologic agents will be used more specifically in the future, for example, by targeting growth factor therapy at those specific components or processes that a given wound uses to heal.