Metastatic Renal Carcinoma Long-Term Survivors Treated with s.c. Interferon-Alpha and s.c. Interleukin-2

Tumor heterogeneity as a rationale for a multi-epitope approach in an autologous renal cell cancer tumor vaccine

PURPOSE

An autologous tumor vaccine already used successfully in the immune therapy of renal cell carcinoma was investigated in detail. The evaluation of potential tumor markers should allow for the assessment of potency according to pharmaceutical regulations.

METHODS

A panel of 36 tumor-associated antigens and cellular marker proteins was characterized in a total of 133 tumor cell lysates by methods such as ELISA, Western blots, and topological proteomics. The induction of tumor-associated antigen-specific antibodies was demonstrated by immunization in mice.

RESULTS

Tumor heterogeneity was demonstrated: none of the tumor-associated antigens investigated were detectable in each tumor lysate. In parallel, the coincidental presence of potential danger signals was shown for HSP-60 and HSP-70. The presence of both antigen and danger signal allowed a successful induction of an immune response in a murine model.

CONCLUSION

The verified tumor heterogeneity indicates the need for a multi-epitope approach for the successful immunotherapy in renal cell carcinoma.

Interleukin-18 synergism with interleukin-2 in cytotoxicity and NKG2D expression of human natural killer cells

Natural killer (NK) cells play an important role in anti-tumor immunity. Interleukin (IL)-18 is an immunoregulatory cytokine that induces potent NK cell-dependent anti-tumor responses when administrated with other cytokines. In this study, we explored the effects of combining IL-18 and IL-2 on NK cytotoxicity as well as expression levels of the NK cell receptor NKG2D in vitro. Freshly isolated PBMCs were incubated for 48 h with IL-18 and IL-2, then CD107a expression on CD3-CD56+ NK cells was determined by three-colour flow cytometry to evaluate the cytotoxicity of NK cells against human erythroleukemia K562 cells and human colon carcinoma HT29 cells. Flow cytometric analysis was also employed to determine NKG2D expression on NK cells. The combined use of IL-18 and IL-2 significantly increased CD107a expression on NK cells compared with using IL-18 or IL-2 alone, suggesting that the combination of these two cytokines exerted synergistic enhancement of NK cytotoxicity. IL-18 also enhanced NKG2D expression on NK cells when administered with IL-2. In addition, blockade of NKG2D signaling with NKG2D-blocking antibody attenuated the up-regulatory effect of combining IL-18 and IL-2 on NK cytolysis. Our data revealed that IL-18 synergized with IL-2 to dramatically enhance the cytolytic activity of human NK cells in a NKG2D-dependent manner. The results appear encouraging for the use of combined IL-18 and IL-2 in tumor immunotherapy.

Immunological heterogeneity of the RCC microenvironment: do targeted therapies influence immune response?

The introduction of targeted agents has substantially improved treatment of metastatic clear-cell renal cell carcinoma (RCC). However, complete responses are rare and therapy is not curative. Moreover, information on the latest generation of potent and selective vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (TKI) suggests that a plateau has been reached in terms of efficacy. Recent data reveal that targeted agents are involved in modulating immune responses in RCC. In addition, current research adds to our understanding of how RCC escapes an effective anti-tumor response with the potential to modulate these processes by drug development. This review provides specific insight into targeted therapy induced changes in the immunological microenvironment of RCC, summarizes the available evidence, and discusses potential therapeutic implications.

Patient-based strategy for systemic treatment of metastatic renal cell carcinoma

There were only a few options 3 years ago to treat metastatic renal cell carcinoma (mRCC), a disease with a very poor prognosis. With the approval of targeted therapies for mRCC since December 2005, this situation has changed dramatically. Currently, oncologists can choose between several promising options to improve the longevity and quality of their patients' lives. A widely accepted treatment scheme for targeted therapies in mRCC does not yet exist. Based on a selective literature search, drawing on studies with six targeted therapies for mRCC, and including data from the latest American Society of Clinical Oncology (ASCO) and European Society for Medical Oncology (ESMO) Annual Meetings, this review introduces the available therapies, evaluates patient-specific criteria for their application and suggests an algorithm for a patient-based treatment scheme. Clinical experiences with sequential therapies are summarized and potential combination therapies discussed. In conclusion, the crucial criteria of the treatment scheme we propose are the tumor burden and the disease pace, as well as the quality of life of a patient. These define whether tumor control or tumor remission should be the primary therapeutic goal. This scheme suggests which kind of therapeutic sequence to pursue to optimize patient care in mRCC.