bryostatin-1 and Carcinoma

Regression of established tumors can be induced by adoptive immunotherapy (AIT) with tumor draining lymph node (DLN) lymphocytes activated with bryostatin and ionomycin (B/I). Tumor antigen-sensitized DLN lymphocytes from BALB/c mice with 10-day 4T1 mammary carcinomas were harvested, activated with B/I, and expanded in culture with either interleukin-2 (IL-2) or IL-7 + IL-15. Cell yields, proliferation, phenotypes, and in vitro responses to tumor antigen were compared for cells grown in different cytokines. These T cells were also tested for antitumor activity against established 4T1 mammary carcinomas after inoculation of tumor cells subcutaneously (s.c.). IL-7/15 resulted in much faster and more prolonged proliferation of B/I-activated T cells than culturing the same cells in IL-2. This resulted in approximately 5-10-fold greater yields of viable cells. Culture in IL-7/15 yielded higher proportions of CD8(+) T cells and a higher proportion of cells with a central memory phenotype. T cells grown in IL-2 had higher interferon-gamma (IFN-gamma) release responses to tumor antigen than cells grown in IL-7/15. Adoptive transfer of B/I-activated T cells grown in IL-7/15 demonstrated much greater efficacy against 4T1 tumors in vivo. Activation of tumor antigen-sensitized T cells with B/I and culture in IL-7 + IL-15 is a promising modification of standard regimens for production of T cells for use in AIT of cancer.

Topics: Animals; Antigens, Neoplasm; Bryostatins; Carcinoma; Cell Culture Techniques; Cell Line, Tumor; Cell Proliferation; Female; Immunologic Memory; Immunotherapy, Adoptive; Interferon-gamma; Interleukin-15; Interleukin-2; Interleukin-7; Ionomycin; Mammary Neoplasms, Experimental; Mice; Mice, Inbred BALB C; Phenotype; Recombinant Proteins; T-Lymphocyte Subsets; Time Factors; Tumor Burden

Protein kinase C (PKC) influences cellular sensitivity to cis-diamminedichloroplatinum(II) (cDDP). We have investigated whether the PKC signal transduction pathway is affected during the development of cellular resistance to cDDP. Activators of PKC, such as phorbol 12,13-dibutyrate (PDBu), enhanced the sensitivity of human small cell lung cancer H69 cells to cDDP by 2-fold but had no effect on the sensitivity of cDDP-resistant H69 cells (H69/CP) to cDDP. The maximum sensitization was achieved with 10 nM PDBu and blocked by down-regulation of PKC with higher concentrations of PDBu (1 microM) or bryostatin 1 (0.1 microM). PKC activity was decreased significantly in H69/CP cells compared to the drug-sensitive variant. A similar reduction in PKC activity was noted in ovarian carcinoma 2008 cells that were resistant to cDDP. A modest decrease in PKC activity was also observed in etoposide-resistant H69 (H69/VP-16) cells but not in Taxol-resistant H69 cells or bleomycin-resistant human head and neck carcinoma A-253 cells. H69 cells expressed conventional PKC alpha and-beta, novel PKC delta, atypical PKC zeta and-iota, and novel/atypical PKC mu. A decrease in cPKC alpha and-beta and an increase in nPKC delta were associated with the cDDP-resistant phenotype. The abundance of aPKC zeta or-iota was unaffected. H69/ VP-16 cells also displayed a reduction in cPKC beta and an increase in nPKC delta. Taxol-resistant H69 cells had no alteration in the expression of any of the PKC isozymes. Thus, a reduction in cPKCs and an increase in nPKC may be associated with cDDP resistance.

Topics: Antineoplastic Agents; Bleomycin; Bryostatins; Carcinoma; Carcinoma, Small Cell; Cisplatin; Drug Resistance, Neoplasm; Enzyme Activation; Etoposide; Female; Head and Neck Neoplasms; Herpes Simplex Virus Protein Vmw65; Humans; Lactones; Lung Neoplasms; Macrolides; Ovarian Neoplasms; Paclitaxel; Phorbol 12,13-Dibutyrate; Protein Kinase C; Signal Transduction; Tumor Cells, Cultured