Growth regulation and co-stimulation of human colorectal cancer cell lines by insulin-like growth factor I, II and transforming growth factor alpha.

We have tested growth factor responsiveness of a panel of eight human colorectal carcinoma cell lines. Insulin-like growth factors I and II (IGF-I and IGF-II) stimulated growth of five lines (HT-29, LS411N, LS513, SW480, WiDr). At 30 ng ml-1 both factors enhanced growth up to 3-fold. They induced half-maximal stimulation at 1.9-6.51 ng ml-1. Even after delayed addition IGF-I and II significantly enhanced growth in a short-term proliferation assay. They exerted maximal effects under limiting serum conditions (0.5% FCS) and at low cell density (1.25-5 x 10(4) ml-1). Using these conditions transforming growth factor alpha (TGF alpha) enhanced proliferation of all IGF-responsive cell lines, except SW480. 1.11-3.31 ng ml-1 were required to obtain a half-maximal response. With 10-20 ng ml-1 maximal stimulation occurred at plateau values different from those for IGF-I/II. Proliferation of all cell lines responsive to both IGF-I and TGF alpha was further enhanced by combining both factors, resulting a synergistic response of LS513, while the effects on HT-29, LS411N and WiDr were additive. With HT-29 and LS411N a 24 h exposure to TGF alpha was sufficient to obtain a full response in the co-stimulatory assay. Our results illustrate the importance of IGF-I/II and TGF alpha as stimulators of growth of colorectal carcinomas

Formule chromosomique de Micropotamogale lamottei (Mammalia, Tenrecidae)

Le caryotype d'un mâle de Micropotamogale lamottei est décrit. La formule chromosomique est de 2N = 38, le nombre fondamental (NF) s'élève à 76. Ce caryotype diverge considérablement de celui des Microgales malgaches, considérés généralement comme les parents les plus proches des Potamogalinae

Etude pronostique comparative de l'evolution in vitro et in vivo des tumeurs colorectales. Communication preliminaire. [Comparative prognostic study of the in vitro and in vivo development of colorectal tumors. Preliminary communication]

In vitro clonal growth of tumour cells may reflect biological properties of cancer and thus have prognostic value. This study seeks to establish correlations between the clinical outcome in patients after surgery for colorectal cancer and clonal growth of their tumours. History, status and follow-up data are collected. Tumour samples taken at operation under sterile conditions are plated immediately in our methylcellulose clonal assay system. Out of 65 consecutive samples, 3 did not yield sufficient cells for culture. Thirty-four (55%) grew more than 0.3 colonies/10(5) cells seeded; cloning efficiency was greater than 10 colonies/10(5) cells in 19. The 28 (45%) failures included 3 benign polyps cultured; 7 samples had visible bacterial or fungal contamination. The other 18 negative cultures may be due to cytotoxicity of the antibiotics or heterogeneity of tumour cells. These preliminary results show that colorectal cancers grow well in vitro in the absence of restricting factors, but they do not confirm the hypothesis that proliferative potential and differentiation are opposing processes. Location of the tumour may play a role, since best growth was seen in tumours of the caecum and terminal colon