Cell subpopulations dispersed from solid tumours and separated by centrifugal elutriation

Abstract

Summary.-The degree of non-neoplastic host-cell infiltration was assessed in 3 in vivo-in vitro tumour models commonly used in radiobiological studies: EMT6/Ro mammary carcinoma, 9L/Ro tumour and KHT sarcoma. While the 2 former tumour models have been shown to be moderately to highly immunogenic when grown s.c., the KHT sarcoma is apparently non-immunogenic. Using differential staining on single-cell suspensions from enzymatically dissociated solid tumours, all 3 tumour types were found to contain large proportions (3060%) of non-neoplastic host cells.The actual host-cell component found in the cell suspensions differed both in type and percentage for the 3 tumours studied. These host and neoplastic cells in the cell suspensions prepared from the solid tumours could readily be separated by centrifugal elutriation. After separation the clonogenic potential of the neoplastic cells was assessed, and was found to be higher than the clonogenic capacity of the unseparated cell suspension by a factor directly related to the host/neoplastic cell ratio. Even after the removal of the host cells, the clonogenic capacities of the neoplastic EMT6 and 9L tumour cells were lower than that of the corresponding in vitro sublines (,30 vs -75%). However, in the KHT sarcoma the removal of the host cell component raised the plating efficiency to .60°/,, which was similar to the value for the in vitro cell subline of this tumour.

Effects of tumour acidification with glucose+MIBG on the spontaneous metastatic potential of two murine cell lines

“…A possible explanation for the lack of a detectable change is offered by Kallinowski et al (1989), who postulated that a decrease in oxygen consumption by tumour cells may be concealed by an up to 70-fold elevation in oxygen consumption by immune cells. Approximately 40% of cells from dissociated KHT-C tumours have been reported to be immune cells, primarily macrophages (Siemann et al, 1981). Alternatively, this observation may be due to the absence of anaesthetics in the current study, use of which has been reported to influence tissue pH e and pO 2 (Buelke-Sam et al, 1978;Kerger et al, 1997).…”

CD8+ T cell-mediated control of distant tumours following local photodynamic therapy is independent of CD4+ T cells and dependent on natural killer cells

“…The regimen-dependent induction of inflammatory responses following PDT could also account for the failure of other groups to detect an effect of Foscan (meta-tetrahydroxyphenylchlorin)-PDT of orthotopic rat liver tumours on liver tumours present outside the treatment field (van Duijnhoven et al, 2003). In addition, NK cell activation of DCs in anti-tumour immunity appears to depend upon tumour expression of NKG2D ligands (Adam et al, 2005), or expression of costimulatory molecules such as CD70, CD80 or CD86 (Kelly et al, 2002); EMT6 tumours are immunogenic (Siemann et al, 1981) respond well to PDT (Korbelik and Dougherty, 1999) and may be more susceptible to immune-mediated control. PDT is likely to be less effective at stimulating systemic anti-tumour immune responses against less immunogenic tumours such as those used in other PDT studies of systemic immunity (van Duijnhoven et al, 2003).…”

Exclusion of host cells during spheroid formation from disaggregated solid tumours

“…There has been much recent interest in the possibility of growing spheroids directly from disaggregated clinical tumour material. Suspensions prepared from solid tumours generally contain a considerable population of normal host cells including macrophages, endothelial cells, lymphocytes and granulocytes (Siemann et al, 1981). The proportions will vary between tumour types, but investigation of two different sublines of the EMT6 mouse tumour have showed that -40% of the total cellular composition consists of macrophages (Stewart & Beetham, 1978;Siemann et al, 1981 (Twentyman & Watson, 1977).…”

“…Suspensions prepared from solid tumours generally contain a considerable population of normal host cells including macrophages, endothelial cells, lymphocytes and granulocytes (Siemann et al, 1981). The proportions will vary between tumour types, but investigation of two different sublines of the EMT6 mouse tumour have showed that -40% of the total cellular composition consists of macrophages (Stewart & Beetham, 1978;Siemann et al, 1981 (Twentyman & Watson, 1977). A suspension prepared from the solid tumour contains -40% host cells and these may be separated from tumour cells by a selective adherence technique (Twentyman & Watson, 1977).…”