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Supplementary Fig. S1 from ABT-263 and rapamycin act cooperatively to kill lymphoma cells in vitro and in vivo

Supplementary Fig. S3 from ABT-263 and rapamycin act cooperatively to kill lymphoma cells in vitro and in vivo

ABT-263 is a potent, orally bioavailable inhibitor of the antiapoptotic Bcl-2 family members Bcl-2, Bcl-xL, and Bcl-w, which is currently in phase I clinical trials. Previous work has shown that this compound has low nanomolar cell-killing activity in a variety of lymphoma and leukemia cell lines, many of which overexpress Bcl-2 through a variety of mechanisms. Rapamycin is a macrolide antibiotic that inhibits the mammalian target of rapamycin complex, leading to cell cycle arrest and inhibition of protein translation. Rapamycin (and its analogues) has shown activity in a variety of tumor cell lines primarily through induction of cell cycle arrest. Activity has also been shown clinically in mantle cell lymphoma and advanced renal cell carcinoma. Here, we show that treatment of the follicular lymphoma lines DoHH-2 and SuDHL-4 with 100 nmol/L rapamycin induces substantial G0-G1 arrest. Addition of as little as 39 nmol/L ABT-263 to the rapamycin regimen induced a 3-fold increase in sub-G0 cells. Combination of these agents also led to a significant increase in Annexin V staining over ABT-263 alone. In xenograft models of these tumors, rapamycin induced a largely cytostatic response in the DoHH-2 and SuDHL-4 models. Coadministration with ABT-263 induced significant tumor regression, with DoHH-2 and SuDHL-4 tumors showing 100% overall response rates. Apoptosis in these tumors was significantly enhanced by combination therapy as measured by staining with an antibody specific for cleaved caspase-3. These data suggest that combination of ABT-263 and rapamycin or its analogues represents a promising therapeutic strategy for the treatment of lymphoma. [Mol Cancer Ther 2008;7(10):3265–74]

AKT1/protein kinase Balpha is a protein-serine/threonine kinase that regulates multiple targets involved in cell survival and cell cycle progression in a variety of cell types including breast cancer cells. To explore the role of Akt1 in mammary gland function and tumorigenesis, transgenic mice were generated that express human AKT1 under the control of the MMTV promoter. Virgin transgenic mice did not exhibit a dominant phenotype, but upon cessation of lactation, a notable delay in involution occurred compared to age-matched non-transgenic mice. The delay in involution coincided with increased hyperplasia as evidenced by an increased number of binucleated epithelial cells and a marked elevation in cyclin D1 expression in mammary epithelium. The delayed involution phenotype corresponded to increased phosphorylation of Thr308 in AKT1 and Ser136 in BAD, but not phosphorylation of Ser21 in GSK-3alpha. There was no evidence of mammary dysplasia or neoplasia during the lifespan of multiparous transgenic mice. These data suggest that AKT1 is involved in cell survival in the lactating and involuting mammary gland, but that overexpression of AKT1 alone is insufficient to induce transformation.