Page 135 - 2014 Printable Abstract Book
P. 135
dependence of HRR and the possible cross-talk between HRR and B-NHEJ. Supported by:
Bundesministerium für Wirtschaft und Technologie“(BMWi: ESA-AO-08-IBER, 50WB1229) and the,
Bundesministerium für Bildung und Forschung“(BMBF: 02NUK005C and 03NUK001B)
(PS1-61) Targeting HSP90 increases he efficacy of ionizing radiation in human non-small cell lung cancer.
Vera Levina; Roberto Gomez-casal; Chitralekha Bhattacharya, PhD; Michael Epperly, PhD; and Mark
Socinski, MD, University of Pittsburgh Cancer institute, Pittsburgh, PA
Background: Ionizing irradiation (IR) is used to treat NSCLC; however, radiotherapy remains
largely palliative due to radioresistance. Recently, we reported that IR-resistant residual cells in NSCLC
expresses a complex phenotype combing cancer stem cell (CSC) and the epithelial to mesenchymal
transition (EMT) traits. The tyrosine kinase receptors (RTK) receptors, such as PDGFRa, EGFR, FGFR and
VEGFR are expressed in nonrelated cells and IR-resistant residual cells. Moreover, PDGFRb is dramatically
upregulated in IR resistant cells. Since all of these RTK receptors, as well as other oncogenic proteins are
client proteins of the molecular chaperone HSP90, NSCLC cells and specifically IR-resistant residual cells
could be highly dependent on HSP90 and sensitive to HSP90 inhibition.
We hypothesize that the inhibition of HSP90 will eliminate IR-resistant residual cells and sensitize NSCLC
cells to IR treatment. Methods/Results: HSP90 inhibitor Ganetespib, kindly provided by SYNTA
Pharmaceuticals, was used in this study. A549 cells and primary human adenocarcinoma cells were
utilized. Using MTT and clonogenic assays we have demonstrated that ganetespib suppresses the
proliferation of NSCLC cells and potentiates the effect of IR treatment. Ganetespib inhibits the growth of
lung tumor spheres. Using a wound healing assay we have determined that ganetespib inhibits motility of
NSCLC cells and IR-resistant residual cells. We also have investigated the effect of ganetespib on the cells
cycle, apoptosis and DNA repair machinery in irradiated cells. Using a SCID mice model, we have
demonstrated that ganetespib applied as monotherapy inhibits the growth of T2821 primary
adenocarcinoma cells in vivo and significantly sensitizes T2821 tumors to IR-treatment.
Conclusion: The HSP90 inhibitor ganetespib potentiates the effect of IR in NSCLC and eliminates IR-
resistant residual cells. Work is supported by the grants: NIH, 1R21CA164740-01 and P50 CA090440.
(PS1-63) Characterization of exosomes derived from irradiated breast cancer cells. Julie Diamond;
Jessica R. Chapman; Beatrix Ueberheide; and Sandra Demaria, NYU School of Medicine, New York, NY
Exosomes are membrane microvesicles (30-100nm) released from living cells that shuttle and
transfer selected intracellular components, including cytokines, growth factors, mRNA, and miRNA.
Tumor-derived exosomes (TEX) allow for communication with a variety of cells, including immune cells,
within the tumor microenvironment or in distant sites. This transfer of information can lead to
downstream effects, and we hypothesized that TEX released from irradiated tumors may play a role in the
abscopal effect by altering the susceptibility of distal metastases to immune-mediated tumor rejection.
To determine if radiation changes the composition of TEX we first treated mouse mammary carcinoma
cells (TSA) in vitro with 0Gy (mock radiation), 1 dose of 20Gy and 3 fractions of 8Gy (8Gyx3). Cells were
cultured in exosome-depleted media. Supernatant fractions were collected 48hr post-treatment and
purified for exosomes using differential ultracentrifugation. Exosomes were lysed for identification of
proteins using liquid chromatography mass spectrometry (LC-MS) followed by MS/MS analyses. Mass
133 | P a g e
Bundesministerium für Wirtschaft und Technologie“(BMWi: ESA-AO-08-IBER, 50WB1229) and the,
Bundesministerium für Bildung und Forschung“(BMBF: 02NUK005C and 03NUK001B)
(PS1-61) Targeting HSP90 increases he efficacy of ionizing radiation in human non-small cell lung cancer.
Vera Levina; Roberto Gomez-casal; Chitralekha Bhattacharya, PhD; Michael Epperly, PhD; and Mark
Socinski, MD, University of Pittsburgh Cancer institute, Pittsburgh, PA
Background: Ionizing irradiation (IR) is used to treat NSCLC; however, radiotherapy remains
largely palliative due to radioresistance. Recently, we reported that IR-resistant residual cells in NSCLC
expresses a complex phenotype combing cancer stem cell (CSC) and the epithelial to mesenchymal
transition (EMT) traits. The tyrosine kinase receptors (RTK) receptors, such as PDGFRa, EGFR, FGFR and
VEGFR are expressed in nonrelated cells and IR-resistant residual cells. Moreover, PDGFRb is dramatically
upregulated in IR resistant cells. Since all of these RTK receptors, as well as other oncogenic proteins are
client proteins of the molecular chaperone HSP90, NSCLC cells and specifically IR-resistant residual cells
could be highly dependent on HSP90 and sensitive to HSP90 inhibition.
We hypothesize that the inhibition of HSP90 will eliminate IR-resistant residual cells and sensitize NSCLC
cells to IR treatment. Methods/Results: HSP90 inhibitor Ganetespib, kindly provided by SYNTA
Pharmaceuticals, was used in this study. A549 cells and primary human adenocarcinoma cells were
utilized. Using MTT and clonogenic assays we have demonstrated that ganetespib suppresses the
proliferation of NSCLC cells and potentiates the effect of IR treatment. Ganetespib inhibits the growth of
lung tumor spheres. Using a wound healing assay we have determined that ganetespib inhibits motility of
NSCLC cells and IR-resistant residual cells. We also have investigated the effect of ganetespib on the cells
cycle, apoptosis and DNA repair machinery in irradiated cells. Using a SCID mice model, we have
demonstrated that ganetespib applied as monotherapy inhibits the growth of T2821 primary
adenocarcinoma cells in vivo and significantly sensitizes T2821 tumors to IR-treatment.
Conclusion: The HSP90 inhibitor ganetespib potentiates the effect of IR in NSCLC and eliminates IR-
resistant residual cells. Work is supported by the grants: NIH, 1R21CA164740-01 and P50 CA090440.
(PS1-63) Characterization of exosomes derived from irradiated breast cancer cells. Julie Diamond;
Jessica R. Chapman; Beatrix Ueberheide; and Sandra Demaria, NYU School of Medicine, New York, NY
Exosomes are membrane microvesicles (30-100nm) released from living cells that shuttle and
transfer selected intracellular components, including cytokines, growth factors, mRNA, and miRNA.
Tumor-derived exosomes (TEX) allow for communication with a variety of cells, including immune cells,
within the tumor microenvironment or in distant sites. This transfer of information can lead to
downstream effects, and we hypothesized that TEX released from irradiated tumors may play a role in the
abscopal effect by altering the susceptibility of distal metastases to immune-mediated tumor rejection.
To determine if radiation changes the composition of TEX we first treated mouse mammary carcinoma
cells (TSA) in vitro with 0Gy (mock radiation), 1 dose of 20Gy and 3 fractions of 8Gy (8Gyx3). Cells were
cultured in exosome-depleted media. Supernatant fractions were collected 48hr post-treatment and
purified for exosomes using differential ultracentrifugation. Exosomes were lysed for identification of
proteins using liquid chromatography mass spectrometry (LC-MS) followed by MS/MS analyses. Mass
133 | P a g e
