Tumor antigen-/cytokine-pulsed dendritic cells in therapy against lymphoma

Combination of cytokine-induced killer and dendritic cells pulsed with antigenic α-1,3-galactosyl epitope-enhanced lymphoma cell membrane for effective B-cell lymphoma immunotherapy

BACKGROUND AIMS

Refractory B-cell lymphomas are difficult to successfully treat with current chemotherapeutic regimens; however, immunotherapy may be an effective form of treatment for these patients.

METHODS

Fourteen refractory lymphoma patients (age, 29-74 y) were enrolled in the trial. α-1,3-galactosyl (α-Gal) epitopes were synthesized on lymphoma cell membranes with the use of bovine recombinant α-1,3-galactosyltransferase (α-GT) and neuraminidase to enhance tumor immunogenicity. Subsequent incubation of processed cell membranes with autologous dendritic cells (DCs) in the presence of human serum containing abundant natural anti-α-Gal immunoglobulin G led to the effective phagocytosis of tumor membranes by DCs. The pulsed DCs and autologous cytokine-induced killer cells were then co-cultured to promote maximum cytotoxicity to lymphoma cells and were infused back into the donor lymphoma patients. Therapeutic responses were assessed by clinical observation, laboratory tests and a computed tomography scan at 6 months after treatment.

RESULTS

Complete and partial remission occurred in four and three patients, respectively. The disease status remained unchanged in five patients, and disease progression was observed in two patients. No serious side effects or autoimmune diseases were observed in any participants. Serum lactate dehydrogenase and β2-macroglobulin decreased in 11 and 14 patients, respectively. All patients showed robust systemic cytotoxicity in response to tumor lysate as measured by interferon-γ expression in peripheral blood mononuclear cells after treatment (P < 0.001). The number of peripheral immune effector cells (CD3(+)/CD4(+), CD8(+)/CD28(+) and CD16(+)/CD56(+) cells) increased significantly (P < 0.05) 3 months after treatment.

CONCLUSIONS

Lymphoma cell-specific α-Gal immunotherapy is safe, effective and has great potential for the treatment of refractory B-cell lymphoma.

Downregulation of STAT3 phosphorylation enhances tumoricidal effect of IL-15-activated dendritic cell against doxorubicin-resistant lymphoma and leukemia via TNF-α

Although disputed by some, increasing evidence suggests that TNF-α synergies with traditional chemotherapeutic drugs to exert a heightened antitumor effect. The present study investigated the antitumor efficacy of recombinant IL-15 in combination with the STAT3 inhibitor cucurbitacin-I in a doxorubicin-resistant murine lymphoma model. The significance of the work is to understand and design effective strategies in doxorubicin resistant lymphomas. TNF-α is downregulated in dendritic cells from mice with Dalton's lymphoma and shows an inverse relationship with disease progression. Doxorubicin-resistant DL cells have elevated levels of Bcl-2 and Mcl-1 and increased phosphorylation of STAT3. These cells are refractory to dendritic cell derived TNF-α. Doxorubicin resistant Dalton's lymphoma is susceptible to dendritic cell derived TNF-α upon stimulation with the STAT3 inhibitor cucurbitacin-I, which downregulates STAT3 and other survival molecules. The combined treatment of low dose of cucurbitacin-I and rIL-15 is ineffective in mice with doxorubicin resistant Dalton's lymphoma, but a similar therapy prolongs the survival of mice transplanted with parental Dalton's lymphoma. Doxorubicin resistant Dalton's lymphoma responds to therapy with high doses of cucurbitacin-I and rIL-15. Dendritic cell derived from mice responded positively to the therapy and regained their tumoricidal properties with respect to growth inhibition and killing of DL tumor cells. Similar to DL, DC derived from CML patients are impaired in TNF-α expression and are unable to restrict the growth of drug-resistant lymphoma and leukemia cells. This combination approach could be used as a new therapeutic strategy for aggressive and highly metastatic doxorubicin resistant lymphoma.