Comparison of the cytotoxic response against ovarian cancer by immune effector cells isolated and expanded from normal donors and ovarian cancer patients.

BACKGROUND/AIMS: The aim of this study was to compare the cytotoxic response against ovarian cancer (OC) cells elicited by different immune effector cells in combination with the cytokines interleukin (IL)-2 and interferon (IFN) α-2b. METHODS: OC cells were co-cultured with peripheral blood mononuclear cells (PBMC) from normal donors or OC patients and IL-2 or IFN α-2b alone or in combination, in order to determine the cytotoxicity. T cells were isolated from healthy donors to determine T cell cytotoxic activity. PBMC from healthy donors and OC patients were expanded in an IL-2/IL-7/IL-12 cocktail with and without anti-CD3 antibody, and the cytotoxic activity measured. Flow cytometry was performed on primary, selected and expanded cells to determine T, B, and natural killer- (NK) cell percentages. RESULTS: Healthy donor PBMC elicited a significant cytotoxic response (59%) compared with OC patient PBMC (7%). T cells enriched from normal donors elicited a significant cytotoxic response (18%) compared with controls lacking effector cells (1.4%); however, the cytotoxicity observed was significantly less compared with unselected PBMC. Expanded effector cells consisted primarily of T cells (98%) and the fold-expansion was significantly higher in the presence of anti-CD3 (19- versus 132-fold). No significant difference in the expansion (either fold-expansion or cell type) was observed between OC patients and healthy donors. Expanded cells from both healthy donors and OC patients elicited a significant cytotoxic response in the presence of IL-2 (19% and 22%) compared with controls. CONCLUSIONS: PBMC from OC patients do not elicit a significant cytotoxic response; however, ex vivo-expanded cells from OC patients are capable of cytotoxic killing similar to unexpanded T cells isolated from normal donors. These data provide the groundwork for further development of cellular therapy against OC.

Functional characterization of a fluorescent highly tumorigenic ovarian cancer line to test cellular therapy in experimental models.

OBJECTIVES: The objective of this study was to functionally characterize a fluorescent highly tumorigenic ovarian cancer line to test cellular therapy in combination with cytokines or chemotherapies in experimental models. METHODS: A fluorescent highly tumorigenic subline (SKOV3-AF2) was derived from the SKOV3 ovarian cancer cell line. Peripheral blood mononuclear cell (PBMC)-mediated cytotoxicity of SKOV3-AF2 in the presence of interleukin 2 (IL-2) and interferon α-2b (IFNα-2b) was assayed by lactate dehydrogenase release. Sensitivity of SKOV3-AF2 cells to polyethylene glycol-IFNα-2b and IL-2 was assayed in a xenograph nude mouse model. Histopathology was performed to determine necrosis and tumor-infiltrating lymphocytes in the solid tumors. Reverse transcriptase-polymerase chain reaction was used for gene expression analyses of E-cadherin and cysteine-rich 61 (CCN1). RESULTS: The SKOV3-AF2 subline exhibits increased cytotoxicity (up to 70%), mediated by PBMCs, IL-2, and IFNα-2b, compared with parental SKOV3-red fluorescent protein (RFP) cells. SKOV3-AF2 cells are more tumorigenic in vivo as indicated by tumor incidence, time to sacrifice, tumor weight, and ascitic fluid production. SKOV3-AF2 tumor growth was inhibited by polyethylene glycol-IFNα-2b but not low-dose IL-2. Histopathology revealed that the tumors consisted of poorly differentiated surface epithelial carcinoma. SKOV3-RFP, and -AF2 cell lines as well as -AF2 tumors expressed E-cadherin. SKOV3-AF2 derived tumors expressed CCN1; however, the SKOV3-RFP and SKOV3-AF2 cell lines did not. CONCLUSIONS: Characterization of SKOV3-AF2 cells revealed that it is more susceptible to PBMC-mediated cytotoxicity than SKOV3-RFP and highly tumorigenic in a xenograph model, and AF-2 tumors express genes that promote aggressive behavior. Collectively, our data suggest that the SKOV3-AF2 subline will be a useful tool to test cellular therapy for the treatment of ovarian cancer utilizing experimental models.