PURPOSE The resistance of tumors to antiangiogenic therapies is becoming increasingly relevant. There are currently no validated predictive biomarkers for selecting which cancer patients will benefit from antiangiogenic therapy. Also lacking are resistance biomarkers that can identify which escape pathways should be targeted after tumors develop resistance to VEGF treatment. Recent studies show...

Natural killer (NK) cells are innate effector lymphocytes that control the growth of major histocompatibility complex class I negative tumors. We show here that T lymphocytes, expanded in vitro in the presence isopentenylpyrophosphate (IPP), induce NK cell–mediated killing of tumors that are usually resistant to NK cytolysis. The induction of cytotoxicity toward these resistant tumors requires ...

Aromatase inhibitors (AI) are a standard-of-care treatment for postmenopausal, estrogen receptor–positive breast cancers. Although tumor recurrence on AI therapy occurs, themechanisms underlying acquired resistance to AIs remain unknown. In this study, we examined a cohort of endocrine-treated breast cancer patients and used a cell line model of resistance to the AI letrozole. In patients treat...

The isolation and purification of at least two distinct macromolecular lipids from murine L1210 tumors either sensitive or resistant to the terephthalanilide NSC 38280 are described. The lipids are extracted from the tumors with chlorofornrmethanol and purified utilizing a series of gel permeation and affinity chromatography columns with chlorofornrmethanol elution. Preliminary characterization...

Her-2/neu(+) tumor cells refractory to antibody or receptor tyrosine kinase inhibitors are emerging in treated patients. To investigate if drug resistant tumors can be controlled by active vaccination, gefitinib and antibody sensitivity of four neu(+) BALB/c mouse mammary tumor lines were compared. Significant differences in cell proliferation and Akt phosphorylation were observed. Treatment-in...

Primary resistance to vincristine (VCR) has been selected in rhabdomyosarcoma xenograft HxRh12 by sequential administration of VCR at 1.5 and subsequently 3 mg/kg/passage. The resistant tumor (HxRh12/VCR-3) was approximately 4-fold resistant to VCR and resistance was stable in the absence of selecting pressure (greater than 2 yr). HxRh12/VCR-3 was 2- to 3-fold cross-resistant to L-phenylalanine...

PURPOSE Drug resistance is a major obstacle in cancer chemotherapy. Although the statistical probability of therapeutic success is known for larger patient groups from clinical therapy trials, it is difficult to predict the individual response of tumors. The concept of individualized therapy aims to determine in vitro the drug response of tumors beforehand to choose effective treatment options ...

Chemotherapy resistance of tumors is an important biological and clinical problem. Studies Troni many tumor types have indicated that resistance may he hased on multiple genetic pathways. Human male (¡ermacell tumors (GCTs) are an especially good model system to study the genetic hasis of tumor sensitivity and resistance to chemotherapy. GCTs are exquisitely sensitive to treatment with DNA-dam...

The PI3K/AKT/mTOR pathway has frequently been found activated in human tumors. We show that in addition to Wnt signaling dysfunction, the PI3K/AKT/mTOR pathway is often upregulated in mouse Msh2(-/-) initiated intestinal tumors. NVP-BEZ235 is a dual PI3K/mTOR inhibitor toxic to many cancer cell lines and currently involved in clinical trials. We have treated two mouse models involving Msh2 that...

S. Moreno, E.M. Galván, N. Vázquez, G. Fiorilli and P.A. Cáceres Guido 1 Institute Leloir Foundation (ex Campomar Foundation)-Biochemistry Institute Research of Buenos Aires (IIBBACONICET), Av. Patricias Argentinas 435, CABA Argentina 2 Maimónides University, Hidalgo 755, CABA, Argentina 3 Microbiology Service, Garrahan Pediatric Hospital, Combate de los Pozos 1881, CABA, Argentina 4 Integrativ...