In vitro modulation of the invasive and metastatic potentials of human renal cell carcinoma by interleukin-2 and/or interferon-alpha gene transfer.

BACKGROUND

Continuous local delivery of interleukin-2 (IL-2) and interferon-alpha (IFN-alpha) via gene transfer appears to be more effective than systemic therapy in preventing the growth of human renal cell carcinoma (RCC) in vitro and in vivo. To understand further if cytokine-gene transfection of RCC could alter certain cellular properties that are associated with the invasive and metastatic potentials of tumor, the authors characterized six cell lines that produce IL-2 and/or IFN-alpha in their expression of intercellular adhesion molecule-1 (ICAM-1) and CD44; binding affinity to extracellular matrix (ECM) components (fibronectin, laminin, type IV collagen, and vitronectin); and preference in forming homotypic aggregation and mRNA levels of c-myc, epidermal growth factor receptor (EGF-R), tumor transforming growth factor-beta (TGF-beta) and type IV collagenase. These six lines were compared with control vector transfected parental R11 line.

METHODS

The expression of ICAM-1 and CD44 was determined by fluorescence-activated cell sorter (FACS) analysis, the tumor cell binding affinity to ECM components was measured by cell attachment assay, the degree of homotypic aggregation was quantified by cell aggregation assay, and the mRNA levels of c-myc, EGF-R, TGF-beta, and collagenase were analyzed by a quantitative polymerase chain reaction analysis.

RESULTS

Both IL-2-gene- and IFN-alpha-gene-modified R11 exhibited enhanced expression of ICAM-1, suppression of CD44, and decreased binding affinity to ECM components, when compared with the R11-control vector. All cytokine-producing tumor lines showed a decreased preference to form homotypic aggregation. Interferon-alpha gene transfer downregulated c-myc, EGF-R, and type IV collagenase mRNA expression, whereas only the higher producers of IL-2 downregulated TGF-beta mRNA expression. Exogenous IL-2 and/or IFN-alpha treatment of a IFN-alpha-resistant RCC enhanced both HLA class I antigen and ICAM-1 expression and suppressed CD44 expression, but had no effect on tumor growth rate.

CONCLUSIONS

The local production of high concentrations of IL-2 and IFN-a at the tumor site may directly alter tumor properties associated with invasive and metastatic phenotypes of RCC. Interleukin-2 and/or IFN-alpha gene therapy may be an effective strategy for treatment of patients with advanced renal cancer.