HIGH VALUE OF THE RADIOBIOLOGICAL PARAMETER D-Q CORRELATES TO EXPRESSION OF THE TRANSFORMING-GROWTH-FACTOR-BETA TYPE-II RECEPTOR IN A PANELOF SMALL-CELL LUNG-CANCER CELL-LINES

Our panel of SCLC cell lines have previously been examined for their r adiobiological characteristics and sensitivity to treatment with TGF b eta(1). In this study we examined the possible correlations between ra diobiological parameters and the expression of the TGF beta type II re ceptor (TGF beta-rII). We have. in other studies, shown that the prese nce of TGF beta-rII was mandatory for transmitting the growth inhibito ry effect of TGF beta. The results showed a statistically significant difference in D-q, i.e. the shoulder width of the survival curve, betw een cell lines expressing TGF beta-rII and cell lines which did not ex press the receptor (P = 0.01). Cell lines expressing TGF beta-rII had a high D-q-value. TGF beta-rII expression did not correlate with any o ther radiobiological parameters. We suggest that an intact growth inhi bitory pathway mediated by the TGF beta-rII may have a significant rol e for the repair of radiation induced DNA damage in SCLC. (C) 1998 Els evier Science Ireland Ltd. All rights reserved.