Tissue engineered tumor models.

Many research programs use well-characterized tumor cell lines as tumor models for in vitro studies. Because tumor cells grown as three-dimensional (3-D) structures have been shown to behave more like tumors in vivo than do cells growing in monolayer culture, a growing number of investigators now use tumor cell spheroids as models. Single cell type spheroids, however, do not model the stromal-epithelial interactions that have an important role in controlling tumor growth and development in vivo. We describe here a method for generating, reproducibly, more realistic 3-D tumor models that contain both stromal and malignant epithelial cells with an architecture that closely resembles that of tumor microlesions in vivo. Because they are so tissue-like we refer to them as tumor histoids. They can be generated reproducibly in substantial quantities. The bioreactor developed to generate histoid constructs is described and illustrated. It accommodates disposable culture chambers that have filled volumes of either 10 or 64 ml, each culture yielding on the order of 100 or 600 histoid particles, respectively. Each particle is a few tenths of a millimeter in diameter. Examples of histological sections of tumor histoids representing cancers of breast, prostate, colon, pancreas and urinary bladder are presented. Potential applications of tumor histoids include, but are not limited to, use as surrogate tumors for pre-screening anti-solid tumor pharmaceutical agents, as reference specimens for immunostaining in the surgical pathology laboratory and use in studies of invasive properties of cells or other aspects of tumor development and progression. Histoids containing nonmalignant cells also may have potential as "seeds" in tissue engineering. For drug testing, histoids probably will have to meet certain criteria of size and tumor cell content. Using a COPAS Plus flow cytometer, histoids containing fluorescent tumor cells were analyzed successfully and sorted using such criteria.

Lymphocytic infiltration of bladder after local cellular immunotherapy.

BACKGROUND: This is a case report of a patient who received cellular immunotherapy, in the form of local injections of autologous stimulated lymphocytes (ASL) into individual tumors in the urinary bladder. A major consideration in cellular immunotherapy being the ability of immune cells to reach all target areas, we hypothesized that direct delivery of effector cells into individual bladder tumors might assure such access. METHODS: ASL were generated by exposing the patient's PBL to phytohemagglutinin and culturing them in the presence of IL-2 to expand the population. ASL were injected into the base of individual bladder tumors three times at intervals of 3 weeks. RESULTS: The patient died of a myocardial infarct, unrelated to cell therapy, 20 days after the third injection. An autopsy was performed. Histological sections of the bladder showed extensive lymphocytic infiltration of virtually the entire organ. DISCUSSION: No conclusions about the therapeutic efficacy of local immunotherapy using ASL are possible. Nevertheless, the observations reported, taken together with reports of therapeutic efficacy of other immunotherapy regimens in the management of bladder cancer, suggest that ready access of stimulated lymphocytes to all regions of the organ may account, in part, for the relatively high rate of therapeutic success reported for various immunotherapy regimens for this malignancy.

Three-dimensional growth patterns of various human tumor cell lines in simulated microgravity of a NASA bioreactor.

Growth patterns of a number of human tumor cell lines that from three-dimensional structures of various architectures when cultured without carrier beads in a NASA rotary cell culture system are described and illustrated. The culture system, which was designed to mimic microgravity, maintained cells in suspension under very low-shear stress throughout culture. Spheroid (particulate) production occurred within a few hours after culture was started, and spheroids increased in size by cell division and fusion of small spheroids, usually stabilizing at a spheroid diameter of about 0.5 mm. Architecture of spheroids varied with cell type. Cellular interactions that occurred in spheroids resulted in conformation and shape changes of cells, and some cell lines produced complex, epithelial-like architectures. Expression of the cell adhesion molecules, CD44 and E cadherin, was upregulated in the three-dimensional constructs. Coculture of fibroblast spheroids with PC3 prostate cancer cells induced tenascin expression by the fibroblasts underlying the adherent prostate epithelial cells. Invasion of the fibroblast spheroids by the malignant epithelium was also demonstrated.

Immunotherapy for recurrent malignant glioma: an interim report on survival.

We present interim survival data for a group of 83 adult patients with recurrent malignant glioma treated by implanting stimulated autologous lymphocytes into the tumour bed following surgical debulking. The patients were treated 6 months or more prior to data analysis. Fifty-nine patients were male and 24 female. The mean age for the entire group was 48.4 years and the mean Karnofsky rating (KR) was 67.2. Eight of the patients had grade II tumours, 33 had grade III tumours and 42 had grade IV tumours. Statistical analysis focuses on tumour grade, KR and patient age, factors that have been shown to affect survival in previous studies. Multifactorial analyses are employed to identify interrelationships among factors related to survival. Seven patients (8%) did not respond to immunotherapy, 76 (92%) had a good initial response. Twenty-five patients (30.1%) are living and 18 (22%) have shown no evidence of recurrence. Results are evaluated in the light of those obtained in trials of other experimental therapies for recurrent malignant gliomas. It is concluded that the present protocol offers a safe and comparatively effective treatment option.

Immunohistochemical detection and correlation between MHC antigen and cell-mediated immune system in recurrent glioma by APAAP method.

As part of an on-going clinical trial of immunotherapy for recurrent malignant gliomas, using alkaline phosphatase-anti-alkaline phosphatase method with monoclonal antibodies, we investigated the correlation between expression of the major histocompatibility complex (MHC) and the subpopulation of tumor-infiltrating lymphocytes (TILs) in 38 glioma specimens (20 grade IV, 11 grade III, and 7 grade II) from 33 patients. Thirty specimens (78.9%) were positive to class I MHC antigen and 20 (52.6%) were positive to class II MHC antigen. The correlations between class I MHC antigen expression and the number of infiltrating T8 (p less than 0.01), and also between class II MHC antigen expression and the number of infiltrating T4 (p less than 0.05) were significant. We conclude that TILs are the result of immunoreaction (host-defense mechanism). 31.6% of specimens had perivascular infiltration of T cells. The main infiltrating lymphocyte subset in moderate to marked perivascular cuffing was T4. Our results may indicate that lack of MHC antigen on the glioma cell surface has a share in the poor immunogenicity in glioma-bearing patients. In addition, considering the effector/target ratio, the number of infiltrating lymphocytes against glioma cells was too small, so the immunological intervention seems to be essential in glioma therapy. Previous radiation therapy and chemotherapy, including steroid therapy, did not influence lymphocyte and macrophage infiltration.

Salvage immunotherapy of malignant glioma.

We present the preliminary results of a phase I trial of adoptive immunotherapy for recurrent or residual malignant glioma. The protocol is based on surgical debulking followed by implantation into the tumor bed of autologous lymphocytes that have been stimulated with phytohemagglutinin-P and then cultured in vitro in the presence of interleukin 2. Fifty-five patients with a mean Karnofsky rating of 64 were treated between February 1985 and March 1987. No significant toxicity was associated with the immunotherapy. Fifty patients had a positive initial response to therapy, nine patients had early recurrence (two to four months after treatment), and 22 patients died. We comment on major differences between the protocol described and other immunotherapy protocols.

Preliminary clinical trial of immunotherapy for malignant glioma.

An immunotherapy protocol based on intracranial implantation of stimulated, autologous lymphocytes into the tumor bed following surgical debulking of malignant glioma is described. Phase I clinical trials in human patients are now in progress. Preliminary data representing the first 39 patients treated are presented briefly.