Lysis of type-i collagen by squamous carcinomas of the head and neck

Abstract

Lysis of type‐1 collagen by squamous carcinomas of the head and neck has beeen studied in freshly excised tissues, xenografts and established cell lines. Investigations with 35 freshly excised tumours showed only low levels of active and total collagenase in both carcinomas and controls. A difference became apparent when the tissues were set up in explant organ culture where a significant (P < 0.05) increase in total collagenase was found in 13/19 tumours compared with paired control tissues over a 4–week culture period. Two xenografts showed little capacity to lyse collagen in vitro and there was only limited evidence of an increase in total collagenase after explantation and growth in organ culture. Twenty tumour cell lines showed low levels of active collagenase. Total collagenase levels were significantly increased (p < 0.05) in 4 of the the cell lines derived from cancers of the tongue; this activity was sustained in subsequent passages. Six control fibroblastoid cell lines also showed low levels of active collagenase. Levels of total collagenase were consistently high, but this activity was transient and declined in subsequent passages. Co‐cultivation experiments with 11 tumour‐cell lines and 5 fibroblastoid cell lines showed some enhanced, synergistic destruction of collagen. Parallel experiments with supernatant media from the carcinoma and fibroblastoid lines showed no enhancement, indicating that intact carcinoma cells and fibroblastoid cells are requited for synergistic collagenolysis to take place.