Processing of Tumor Tissues for Vaccination with Autologous Tumor Cells

Abstract

Vaccination with gene-transfected tumor cells has recently been proposed as a new strategy in the immunotherapy of cancer. Since autologous tumor cells provide an optimal antigen profile, the possibility of generating single cell suspensions from renal cell carcinoma (RCC), malignant melanoma (MM), colon carcinoma (CC), and non-small-cell lung cancer (NSCLC) biopsies was investigated. One hundred and seventy-four tumor biopsies were processed by mechanic and enzymatic dissociation, yielding 1-2 × 10⁶ cells/g tumor (median), irrespective of tumor type. Primary tumor cell cultures (PTCC) of > 10⁷ cells were established from 29 of 86 (34%) RCC, 14 of 38 (37%) MM, 11 of 23 (48%) NSCLC and 4 of 27 (15%) CC specimens. The amount of non-tumor cells, as assessed by morphology and immunocytology, was generally low ( < 30%) in RCC (35 of 41) and MM (11 of 17), while it exceeded 60% in 8 of 11 PTCC from NSCLC and 3 of 11 CC. A high tumor cell yield was obtained in biopsies with a high degree of vascularization and in the virtual absence of necrosis. Thus, PTCC > 10⁷ cells were obtained in 73% of MM with a high degree of vascularization and in 22% of MM with a low degree of vascularization (p < 0.007). Long-term tumor cell cultures exceeding 20 passages were established in 24 of 86 (18%) RCC, 7 of 38 (18%) MM and 3 of 27 (11%) CC, while successful implantation in nude mice was achieved in 8 of 20 RCC and 5 of 10 MM. Thus, under the conditions described, >10⁷ primary tumor cells of high purity could be generated from about one third of RCC and MM biopsies, while the success rate increased to > 50 and > 70%, respectively, in samples with a high degree of vascularization generated by an optimized biopsy technique excluding necrotic parts.

Pro-Inflammatory and T Cell Inhibitory Cytokines Are Secreted at High Levels in Tumor Cell Cultures of Human Renal Cell Carcinoma

“…We cultured 27 different PTCC of RCC for a minimum of 14 days changing medium sparingly until we obtained a confluency of at least 80% of cultured cells. As previously published, at the end of this culture period each of the examined PTCC had more than 70% of tumor cells as confirmed by subsequent analysis of morphology and immunocytochemistry [3]. No other cells except for small amounts of fibroblast-like cells were detected after this culture period.…”

“…PTCC were obtained as previously described [3, 7]. Patients with diagnosed RCC subjected to surgery at the Department of Urology were randomly included in this study.…”

“…PTCC were randomly selected for analysis from a previously published study [3]. Since supernatant of each selected PTCC was limited, main emphasis of analysis was placed on pro-inflammatory and anti-inflammatory cytokines.…”

“…Autologous cells from primary tumor cell cultures (PTCC) have been of major interest for such a therapy based on the assumption that they are more likely to retain the original antigenic composition [1]. However, vaccination protocols based on autologous cells from PTCC are limited because of the difficulty to obtain high numbers of tumor cells for vaccination [2, 3]. On the other hand, cell lines (CL) are regularly available and yield high cell numbers, but may not express the original antigenic composition of tumor-associated antigens (TAA) [4].…”

A Systematic Overview of Cancer Immunotherapy: An Emerging Therapy

“…Whole cell vaccines may be autologous or allogenic: Autologous: If the tumor cells are obtained from patient itself then it is known as an autologous or self-tumor cell vaccine [31].…”