bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 3554: The fungal metabolite galiellalactone inhibits ALDH positive prostate cancer cells
Authors: Hellsten Rebecka , Dahlman Anna , Culig Zoran , Johansson Martin , Sterner Olov , Bjartell Anders
Published: February 2011

Introduction: Tumor stem cells have shown resistance to conventional cancer therapy and may be a cause for recurrent cancer, making tumor stem cell targeted therapy attractive. The fungal metabolite galiellalactone is suggested to be a Stat3 specific inhibitor and we have previously shown that galiellalactone inhibits prostate cancer (PCa) cell growth, both in vitro and in vivo, in PCa cells expressing phosphorylated Stat3 (Hellsten et al, 2008). Aldehyde dehydrogenase (ALDH) has shown promise as a marker of cancer stem cells and in this study we investigated the ALDH activity in human PCa cell lines and the effects of galiellalactone on ALDH+ PCa cells.

Methods: The human PCa cell lines DU145, LNCaP, and long-term interleukin-6 stimulated LNCaP (LNCaP-IL6) cells were used. Galiellalactone was prepared by synthesis (Johansson & Sterner, 2002). PCa cells were subjected to Aldefluor assay followed by flow cytometry to detect ALDH+ subpopulations. WST-1 proliferation assay was performed to study the effect of galiellalactone on proliferation of ALDH+ and ALDH- cells sorted from LNCaP-IL6 cells.

Results: In DU145 cells 2 ± 0.25% of the cells were ALDH+ and in LNCaP-IL6 cells, 2 ± 0.36% were ALDH+. No ALDH+ cells were detected in LNCaP cells. Treatment with 5, 10, 25 or 50 µM galiellalactone for 24h decreased the ALDH+ cell population in DU145 and LNCaP-IL6 cells in a dose dependent manner: 25 µM galiellalactone decreased the ALDH+ population in DU145 cells by 40% and by 75% in LNCaP-IL6 cells. In LNCaP-IL6 cells a dose dependent decrease in ALDH+ cells was observed after 72h (65% decrease at 25 µM galiellalactone). However, in DU145 cells no difference in the relative amount of ALDH+ cells was observed in galiellalactone treated DU145 cells compared to untreated control cells after 72h. The proliferation was decreased by galiellalactone in a dose dependent manner in all cell populations isolated from LNCaP-IL6 cells. The proliferation of ALDH+ cells isolated from LNCaP-IL6 cells was inhibited by 75%, ALDH- cells by 75% and unsorted LNCaP-IL6 cells by 80% after treatment with 25 µM galiellalactone for 48h.

Conclusions: ALDH+ subpopulations, possibly representing tumor stem cell populations were detected in human PCa cell lines, and were clearly inhibited by galiellalactone. ALDH is associated with cell growth and drug resistance, and targeting ALDH+ PCa cells with galiellalactone may be a novel potent treatment against therapy resistant PCa. The effect and mechanism of galiellalactone treatment of ALDH+ PCa cells will be further investigated.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3554.
Abstract 3559: Celastrol, a unique multifunctional pharmacophore with multiple targets as an effective therapeutic against ErbB2-overexpressing cancers
Authors: Raja Srikumar M. , Clubb Robert J. , Ortega-Cava Cesar , Duan Lei , Bailey Tameka A. , Band Vimla , Band Hamid
Published: February 2011

Celastrol, a novel triterpene natural product, has shown immense promise against various cancer models including prostate cancer, pancreatic cancer, leukemia, and melanoma. A unique property of Celastrol is its ability to affect multiple oncogenic cellular targets that include the proteasome, HSP90, I Kappa B Kinase and the cellular redox-balance system. Celastrol could therefore be viewed as a multifunctional pharmacophore simultaneously affecting multiple targets within oncogenically transformed cell. In this paper we explore the properties of this unique pharmacophore as therapeutic agent for treating ErbB2-overexpressing breast cancers. Celastrol not only induced ubiquitinylation and degradation of ErbB2 and other HSP90 client proteins; it also increased cellular ROS levels, and killed ErbB2-overexpressing cells with higher selectivity. Comparison of IC50 values amongst a panel of breast cancer cell lines indicated a strong correlation of basal ROS-levels to sensitivity to killing. ErbB2-overexpression led to increase in basal ROS and consequently ErbB2-high cells were more sensitive to Celastrol than ErbB2-low cells. Celastrol also strongly synergized with ErbB2-targeted therapeutics, Trastuzumab and Lapatinib, resulting in enhanced ErbB2-specific cellular cytotoxicity at substantially reduced doses of Celastrol. Pharmacogenomic expression analysis comparing 17-AAG and Celastrol confirmed several common signatures and revealed unique signatures. Celastrol, but not 17-AAG, could potently induce depletion of Aurora A Kinase at both the transcript as well as protein level, adding to the spectrum of targets, given the importance of Aurora Kinase as a target in development of anti-cancer therapeutics. In vivo xenograft experiments using ErbB2-overexpressing breast cancer model confirmed the potential of Celastrol as a therapeutic agent for the treatment of ErbB2-overexpressing breast cancers.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3559.
Abstract 3601: Evaluation of a mathematical modeling framework to describe combination therapy with Gemcitabine
Authors: Spilker Mary E. , Yamazaki Shinji , Blasina Alessandra , Hallin Jill , Bartkowski Darian M. , Vicini Paolo
Published: February 2011

The quantitative assessment of the effectiveness of chemotherapeutic combinations is of increasing interest. This is especially true given the complexities of different dosing schedules and animal model systems. This work evaluates a recently proposed mathematical modeling framework (Koch et al., J Pharmacokinet Pharmacodyn 36:179-197, 2009), and modifications thereof, for quantifying synergisms between drugs used in combination therapy based on preclinical data. In this study, we evaluated published NSCLC (H460a) tumor growth inhibition (TGI) data following treatment with Erlotinib and Gemcitabine (Higgins et al., Anticancer Drugs 15: 503-512, 2004), administered both alone and in combination. We simultaneously modeled the pharmacodynamic data from all therapeutic regimens. TGI data from both monotherapy and combination therapy were adequately described. The results suggest that Erlotinib and Gemcitabine at sub-maximal doses work in a synergistic manner to reduce tumor growth. This modeling framework may prove useful in the design and optimization of preclinical experiments involving drug combinations.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3601.
Abstract 3602: Radiation pharmacogenomics: an integrative analysis approach to identify biomarkers using the human lymphoblastoid cell lines
Authors: Hou Junmei , Niu Nifang , Qin Yuxin , Fridley Brooke L. , Kalari Krishna , Jenkins Gregory , Batzler Anthony , Wang Liewei
Published: February 2011

Background Radiation therapy is used to treat half of the all cancer patients. Response to radiation therapy varies widely, in terms of both response and toxicity related events. Previous studies suggested almost 80% of the variation in normal tissue response to radiation treatment was likely to be due to genetic factors. Therefore, we performed a genome-wide association study (GWAS) to identify biomarkers that might help predict radiation response using a the “Human Variation Panel” lymphoblastoid cell lines (LCLs) that consists 287 ethnically defined cell lines.

Method Basal gene expression level, 1.3 million genome-wide SNP data were obtained for 287 human LCLs using Affymetrix U133 plus 2.0 GeneChip, Illumina HumanHap 550K, 510S BeadChips and Affymetix SNP Array 6.0. Radiation cytotoxicity assay was also performed to obtain the area under radiation dose response curve (AUC), a summary measure for cytotoxicity for the same cell lines. Functional validation of candidate genes, selected based on the integrated analysis of SNP, expression and AUC data, was performed in multiple cancer cell lines using specific siRNAs followed by MTS and colony formation assays.

Results 27 loci, containing at least 2 SNPs of p values <10−4 within 50kb were associated with radiation AUC. 270 expression probe sets were associated with radiation AUC (p< 10−3). The integrated analysis of 27 loci, 54,000 basal expression probe sets and radiation AUC identified 50 unique SNPs associated with AUC were also associated with gene expression of 39 unique annotated genes. In addition, these 39 genes were associated with radiation AUC with p values <10−3. Based on the GWAS and integrated analysis of SNP, expression array and radiation AUC data, 22 genes were selected for functional validation studies using siRNA knock down followed by MTS and colony formation assays in multiple tumor cell lines. C13orf34 (Bora), MAD2L1, PLK4, TPD52 significantly altered the radiation sensitivity in at least 2 cancer cell lines for both MTS and colony formation assays (p<0.05). Knock down of DEPDC1B, a gene containing 2 SNPs at the 3′-end that was significantly related with Bora gene expression level (p<10−4) significantly desensitized cancer cells to radiation treatment. Both microarray data and QRT-PCR analysis indicated that expression levels for those two genes were significantly correlated. Conclusion Our results using the lymphoblastoid cell lines might help identify novel biomarkers that contribute to variation in response to radiation therapy and help understand the mechanisms underlying the association.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3602.
Abstract 3605: Enterohepatic circulation of indolecarboxamide ML-970 (NSC 716970), an investigative anticancer agent
Authors: Rayburn Elizabeth , Wang Wei , Grau Silvana , Li Haibo , Xu Hongxia , Zhang Xu , Li Mao , Sommers Charnell , Jia Lee , Lee Moses , Zhang Ruiwen
Published: February 2011

ML-970 (NSC 716970), an analog of CC-1065 (a DNA minor-groove binding agent) is under preclinical investigation as a novel anticancer agent. The compound has shown in vitro and in vivo anti-cancer activity. As part of the preclinical evaluation of this agent, we carried out pharmacokinetic studies of ML-970 in CD-1 and nude mice. Of interest, we observed that there was minimal urinary and fecal excretion of the agent within the first 24 hr and relatively low concentrations of the compound in tissues examined (lungs, kidneys, heart, spleen, brain). Additionally, the compound was still detectable at low levels in the plasma for at least 8 hr, and in tissues for at least 24 hr after administration, regardless of the routes of administration. Although high levels of plasma protein binding of the compound may be partially responsible, it was apparent that other factors might be contributing. To examine the underlying mechanism, we performed a pharmacokinetic study evaluating the distribution of the compound in tissues, organs, and organ contents (plasma, liver, lungs, kidneys, spleen, heart, brain, stomach, stomach contents, small intestine, small intestine contents, large intestine, large intestine contents, gallbladder, muscle, urine and feces) after i.v. and oral administration. We found the highest levels of the compound in the gallbladder, small intestine, small intestine contents, large intestine contents and liver, regardless of route of administration. Concentrations of 314.7μg/g, 1383.5μg/g, and 392.6μg/g for 0.5, 2, and 8 hr after i.v. injection, and 28.0μg/g, 313.1μg/g, and 123.7μg/g for 0.5, 2, and 8 hr after oral administration, respectively, were observed for the gallbladder. Average concentrations higher than 19 μg/g were found in the other tissues for at least one time point (range: 19.3μg/g to 286.2μg/g). The high concentrations present in gastrointestinal and hepato-biliary organs, persistence of the compound, and relatively low levels of urinary and fecal excretion during the first 24 hr, indicate that the compound undergoes enterohepatic circulation. These results should be useful for interpretation of future preclinical and clinical developmental studies of ML-970. (This work was supported by NCI Contract N01-CM-52207.)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3605.
Abstract 3607: The effect of gefitinib on the expression of c-MYC and TSP-1 in cancer cells
Authors: Suenaga Mitsuhiro , Tei Chuwa , Akiyama Shin-ichi
Published: February 2011

Gefitinib is a selective inhibitor of epidermal growth factor receptor tyrosine kinase, and is known to suppress tumor angiogenesis. We previously reported that gefitinib suppressed E2F-1 expression and telomerase activity in A431 and A549 cells. The expression of hTERT was increased by c-MYC, whereas we found that 5-FU decreased the expression of c-MYC and increased Thrombospondin-1 (TSP-1) expression. In the present study, we examined the effects of gefitinib on the expression of c-MYC and TSP-1 in human epidermmoid carcinoma A431 and lung adenocarcinoma A549 cells. Gefitinib suppressed the expression of c-MYC in both of two cell lines within 12 hours after gefitinib exposure, however, the expression of c-MYC mRNA was reduced only in A431 cells. A549 cells are known to have K-RAS mutation but A431 cells do not. We suppose that post-transcriptional inhibition or degradation of c-MYC had been induced by the treatment with gefitinib. MG132, a proteasome inhibitor, could inhibit the suppression of c-MYC expression by gefitinib exposure in both of these cells. Thus, the promotion of c-MYC degradation may be one of the mechanisms of the suppression of c-MYC expression by gefitinib exposure on these cells.

On the other hand, in A549 cells, 5-20μM of gefitinib suppressed the expression of c-MYC after incubation for 96 hours too, while TSP-1 expression was increased by gefitinib. In A431 cells, 0.12-1.0μM of gefitinib affected the expression of c-MYC and TSP-1. As in A549 cells, TSP-1 expression was up-regulated but the expression of c-MYC was attenuated by gefitinib. Our findings suggest that the anti-angiogenic effects of gefitinib might be, at least in part, due to TSP-1 expression augmented by gefitinib.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3607.
Abstract 361: Large scale virtual screening to identify novel inhibitors of Fyn as potential drugs for cancer treatment
Authors: Mottamal Madhusoodanan , Kim Jong-Eun , Kang Nam Joo , Lee Ki Won , Sosa Carlos P. , Bode Ann M. , Dong Zigang
Published: February 2011

Protein kinases are involved in a number of signaling cascades and they are considered as one of the major classes of potential drug targets. Overexpression of protein kinases is often found in many human cancers. Fyn, a member of the Src family of tyrosine kinases, plays a critical role in T-cell receptor signaling, brain function, and cell adhesion-mediated signaling. More importantly, Fyn has oncogenic potential and is involved in carcinogenesis processes, including skin cancer development. These properties make Fyn an ideal molecular target for chemoprevention of skin cancer and other diseases. Molecular docking-based virtual screening has become an important tool in the drug discovery process, and it significantly reduces the number of possible chemical compounds to be investigated. In the present study, we carried out virtual screening of chemical databases to find potential inhibitors of Fyn by targeting the ATP-binding pocket. Because binding of ATP to a protein kinase is essential for the phosphotransferase activity of kinases, the ATP-binding pocket is often considered as the first potentially effective target of most inhibitor screens. Potential Fyn kinase activity inhibitors were identified based on the docking score and selected compounds were subjected to in vitro and cellular assays. The in vitro kinase assay has resulted in the identification of a compound with strong (<50 nM) inhibition of Fyn kinase activity. The same compound was found to suppress UVB-induced Fyn kinase activity in JB6 P+ cells. The inhibitor also suppressed UVB-induced cyclooxygenase-2 expression in JB6 P+ cells, indicating its involvement in skin carcinogenesis. Thus, by using virtual screening, we have identified a potential drug candidate to prevent UVB-induced skin cancer. Studies are in progress to validate our observations in vivo.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 361.
Abstract 3611: LY2801653, an orally available small molecule inhibitor of c-Met, demonstrated broad antitumor efficacy in patient derived xenograft models
Authors: Yang Wei J. , Credille Kelly , Gao Hong , Uhlik Mark , Pomeroy Julie , Walgren Richard , Shih Chuan , Baltes Steffen , Beckers Thomas , Yingling Jonathan M.
Published: February 2011

The receptor tyrosine kinase c-Met and its ligand hepatocyte growth factor (HGF) play important roles in cell growth, migration, and survival. Dysregulation of the c-Met/HGF signaling pathway has been found in many human malignancies. LY2801653 was identified and developed as a novel, potent, and orally active small molecule inhibitor of human c-Met. It demonstrated dose dependent inhibition of c-Met phosphorylation in xenograft tumors with a long lasting PD effect. In the current study, the anti-tumor activity of LY2801653 was evaluated in a panel of human patient derived xenograft models. LY2801653 displayed potent anti-tumor efficacy in a number of non small cell lung, renal, pancreatic, and breast tumor models. Examination of c-Met expression in these tumors by immunohistochemistry (IHC) revealed a good correlation between response and c-Met expression in the tumor tissue. Interestingly, the two non small cell lung adenocarcinoma models LXFA526 and LXFA1647 that were resistant to EGFR inhibitors Cetuximab and Erlotinib, displayed high sensitivity towards LY2801653. High level of genomic amplification of c-Met locus was found in these models, consistent with the hypothesis that c-Met activation represents one of the resistant mechanisms to EGFR inhibition. LY2801653 treatment led to increase in functional vessel areas, and decrease in tumor hypoxia. Enhanced anti-tumor efficacy was achieved when Erlotinib was combined with LY2801653. In summary, these results demonstrated the promising therapeutic potential of LY2801653 in mono and combination therapy of cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3611.
Abstract 3614: Multi-targeted kinase inhibitor E7080 showed anti-tumor activity against medullary thyroid carcinoma and squamous thyroid carcinoma cell line based on RET and VEGFR2 tyrosine kinase inhibition
Authors: Matsui Junji , Minoshima Yukinori , Tsuruoka Akihiko , Funahashi Yasuhiro
Published: February 2011

There are about 37,000 and 8,000 new cases of thyroid cancer each year in the US and JP respectively, according to reports of the National Cancer Institute and National Cancer Center in Japan. Thyroid cancer is one of most common cancers after age 30, and its aggressiveness increases significantly in older patients. VEGFR tyrosine kinase inhibitors showed anti-tumor activity against thyroid carcinoma in early clinical study and some of inhibitors have been tested in late stage of clinical trial.

E7080, a multi-targeted kinase inhibitor, potently inhibits VEGFR1-3, FGFR1-4 and RET tyrosine kinases and has been tested in several PhII trials including thyroid carcinoma trial. In this study, we report the efficacy of E7080 as an anti-cancer agent for thyroid carcinoma, based on both anti-tumorigenic activity and anti-angiogenic activity.

E7080 inhibit RET kinase and VEGFR2 kinase with Ki values of 1.5 and 0.74 nmol/L, respectively, in cell free kinase assays. E7080 inhibited proliferation and phosphorylation of RET as well that of downstream Erk1/2 in medullary thyroid carcinoma (MTC) cell lines, TT and MTC-M, which expressed RET kinase in a dose dependent manner. E7080 showed significantly anti-tumor activity at the dose of 10-100 mg/kg in TT xenograft and 1-100 mg/kg in MTC xenograft without affecting microvessel density, suggesting that anti-tumor activity was caused by anti-tumorigenic activity based on RET kinase inhibition. On the other hand, E7080 did not show anti-proliferative activity against thyroid squamous carcinoma cell line, SW579, which did not expressed RET kinase, even at 10 µmol/L of E7080. While E7080 significantly inhibited in vivo growth of SW579 tumor in nude mice, accompanied by decreased of microvessel density within xenografted tumors at 3 - 100 mg/kg.

These results demonstrated that the blockage of RET and VEGFR2 was a promising therapeutic strategy against several types of thyroid carcinoma and E7080, a dual inhibitor of both VEGFR2 and RET tyrosine kinase, is warranted to be examined for thyroid cancer patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3614.
Abstract 3619: Inhibition of FLT3 autophosphorylation and downstream signaling both in vitro and in vivo by AC220, a second generation potent and selective FLT3 inhibitor
Authors: Gunawardane Ruwanthi , Rooks Allison , Dao Alan , Brigham Daniel , Ricono Jill , Zarrinkar Patrick , Bhagwat Shripad , Belli Barbara , Wierenga Wendell , Armstrong Robert
Published: February 2011

Fms-like tyrosine kinase 3 (FLT3) is thought to be a major driver in the pathogenesis of acute myeloid leukemia (AML). FLT3-activating mutations are found in ∼ 30% of AML patients and are associated with poor outcome in this patient population. AC220 is a small molecule kinase inhibitor with potent and selective FLT3 inhibitory activity. Here we characterize the effect of AC220 on FLT3 autophosphorylation, activation of downstream signaling pathways (STAT5, ERK and AKT), cell cycle distribution, and apoptosis endpoints in multiple leukemia cell lines expressing either wild type FLT3 (FLT3-WT, SEM-K2 cells (FLT3-WT overexpression) and RS4;11 cells (FLT3-WT)) and/or ITD-mutated FLT3 (FLT3-ITD, MV4-11 (FLT3-ITD), MOLM-14 (FLT3-ITD/FLT3-WT)). Across each of these parameters we also compare the effects of AC220 to those of other known FLT3 inhibitors including, sorafenib, sunitinib, lestaurtinib, and midostaurin. AC220 inhibited FLT3 autophosphorylation in both FLT3-WT and FLT3-ITD cells with roughly equal potency, while other FLT3 inhibitors showed differential pFLT3 inhibition across several cell lines. Although AC220-mediated inhibition of FLT3 autophosphorylation was observed in all cell lines, subsequent cell death was only detected in the cell lines with activated FLT3. This contrasts with other FLT3 inhibitors, where potent inhibition of cell proliferation in the non-FLT3 activated RS4;11 cells was observed, highlighting the lack of FLT3 selectivity of these compounds. Consistent with FLT3 inhibition, AC220 also inhibited constitutively activated STAT5, ERK and AKT in these cell lines, suggesting that one or more of these pathways play a role in FLT3-mediated cell growth and survival. Furthermore, the inhibition of these downstream markers correlated with the inhibition of FLT3 across each of the FLT3 inhibitors tested. Lastly, in an MV4-11 murine xenograft model, AC220 administration resulted in the reduction of phosphorylated FLT3 and downstream signaling molecules concomitant with tumor reduction. Together, these data suggest that selective FLT3 inhibition is sufficient to inhibit the growth and induce cell death of FLT3-driven leukemia cells. AC220 is currently being evaluated in a phase II clinical trials in relapsed or refractory AML patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3619.
Abstract 3625: Exogenous short-term activation of c-Met and EGFR sensitizes them to kinase inhibitors
Authors: Zhang Ying , Farenholtz Kaitlyn , Yang Yanzhi , Guessous Fadila , Kofman Alexander V. , Christensen James , Abounader Roger
Published: February 2011

Activation of the c-Met and EGFR receptor tyrosine kinases induces brain tumor malignancy and is associated with poor clinical outcome of brain tumor patients. Consequently, c-Met and EGFR are promising targets for the therapy of brain tumors and clinically applicable inhibitors of these receptors have been developed by biotechnology and pharmaceutical companies. We tested the effects of a specific and potent c-Met kinase inhibitor (PF-2341066) on glioma cells and glioma stem cells. Surprisingly, we found that the inhibitor induced significantly greater cell death when c-Met was shortly pre-activated with its ligand hepatocyte growth factor (HGF). Glioblastoma cells (U87, U373), primary glioblastoma cells (GBM10) and glioblastoma stem cells (1228, 0308) were pre-treated with 20 ng/ml HGF for 2h, 4h, 6h, 8h, 16h or 24h prior to treatment with PF-2341066 (100 nM for established and primary cells and 300 nM for cancer stem cells) for 24 hr. The cells were subsequently assessed for apoptosis using annexin-V flow cytometry. The results showed that the inhibitor induced significantly greater (34-79%) absolute cell death in pre-activated cells than in non-activated cells. The optimal time of pre-activation that achieved greatest sensitization of the receptor to kinase inhibitor-induced cell death was 2-4 hours. Using a similar experimental approach, we also tested the effects of EGFR pre-activation on EGFR inhibitor erlotinib-induced cell death in glioma cells. Glioma cells were pre-treated with EGF (100ng/ml) for 3h, 6h, 16h or 24h prior to treatment with erlotinib (2.5 µM) for 24 hrs and assessment of cell death by annexin V flow cytometry. EGFR pre-activation led to significantly greater (138 %) erlotinib-induced cell death than without pre-activation. Based on the above findings, we hypothesize that short-term exogenous activation of c-Met, EGFR and possibly also other receptor tyrosine kinases can trigger fast oncogene addiction that sensitizes tumor cells to death induced by receptor tyrosine kinase inhibitors. We are currently testing this hypothesis using in vivo glioblastoma animal models. Verification of this new hypothesis would imply that quick short-term activation of tyrosine kinase receptors by bolus delivery of receptor tyrosine kinase ligands would sensitize tumors to kinase inhibitors and therefore improve the efficacy of these inhibitors in cancer therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3625.
Abstract 3636: The complex mechanism of resistance of human neuroblastoma cells to chemotherapeutic drugs
Authors: Clark Sandra H. , Lautz Timothy B. , Zheng Xin , Holub Janette L. , Qui Yi-Yong , Chu Fei , Madonna Mary Beth
Published: February 2011

It has become evident that the biological processes which allow malignant cells to survive in the presence of cytotoxic drugs are extraordinarily complex, and recent findings indicate that a multitude of cellular defense mechanisms may be involved in the development of drug resistance. In order to dissect the dynamic changes in gene expression during the process of acquiring drug resistance, four human neuroblastoma cell lines (IMR 32, BE(2)-C, SK-N-SH and SH-SY5Y) were used to generate drug-resistant cell lines using clinically appropriate chemotherapeutic agents (Doxorubicin and Busulfan). Additionally, in order to understand the physiological role of histone deacetylase (HDACs) in the development of drug resistance in human neuroblastoma and to determine if this development can be delayed or totally suppressed by the HDACs inhibition, the cells were separated into those that were pretreated with a histone deacetylase (HDAC) inhibitor: suberoylanilide hydroxamic acid (SAHA), and those that were not pretreated. Cells were deemed drug-resistant when the cells were able to grow efficiently in drug concentrations of two log concentrations higher than the IC50 level. Neuroblastoma cells were collected at each log phase increase of cytotoxic agent to compare changes in P-glycoprotein and midkine expression; cross-resistance between chemotherapeutic agents, and presence of survival proteins in each group. The creation of these resistant human neuroblastoma cell lines and the determination of the transcriptional changes occurring as the cells become resistant may have important implications for clinical treatment of human neuroblastoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3636.
Abstract 3639: Cell death mechanisms associated with the carbamoylating activity of the anticancer prodrug Laromustine
Authors: Paine Adam N. , Praggastis V. Alexandra , Dale Lindsay E. , Tepper Jared L. , Reichelderfer Bridget , Rice Kevin P.
Published: February 2011

The preclinical anticancer prodrug Laromustine (VNP40101M; Cloretazine) yields 2-chloroethylating and methyl carbamoylating activities upon activation in cells. While the induction of DNA damage from its chloroethylating activity is widely considered to be the primary cause of its therapeutic cytotoxicity, Laromustine's carbamoylating activity has proven critical to the drug's mechanistic profile. Methyl isocyanate, the carbamoylating species derived from Laromustine in situ, can enhance the effectiveness of DNA damaging agents, including the cogenerated chloroethylating agent. This consequence is thought to be a result of a diminishment of cellular DNA damage response. However, carbamoylating agents themselves cause acute cell death in cultured mammalian neoplastic cells, principally via apoptosis. Several overlapping cell death pathways can be induced upon exposure to Laromustine's carbamoylating activity. Using Laromustine and its analogs, the chloroethylating-only 90CE and the carbamoylating-only 101MDCE, we identified molecular markers of apoptosis via Western blot analysis and flow cytometry. Poly(ADP-ribose) polymerase (PARP) is often proteolyzed by caspase-3 in the course of an apoptotic death. We report here that Laromustine, with its carbamoylating activity, induced PARP cleavage similarly to the cytotoxic agent etoposide in HL-60 human leukemia cells. In addition, flow cytometry analyses using FITC-annexin V / propidium iodide staining revealed that the carbamoylating activity of Laromustine is responsible for substantial apoptosis in HL-60 cells at clinically relevant doses within three hours of drug treatment. However, the DNA damaging, 2-chloroethylating activity did not induce appreciable apoptosis in similar experiments. Levels of poly(ADP-ribosyl)ation and expression levels of the Bax and Bcl-2 proteins are also being investigated. Given its effects on DNA repair systems and its provocation of apoptosis, methyl isocyanate continues to demonstrate its utility to the cytotoxic action of Laromustine.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3639.
Abstract 3640: Increased anti-tumor effects of sequential docetaxel followed by 5-FU treatment against human oral cancer cells
Authors: Tamatani Tetsuya , Ferdous Tarannum , Uchida Daisuke , Nagai Hirokazu , Miyamoto Youji
Published: February 2011

[Background] Docetaxel (TXT), a novel member of the taxoid family, and 5-fluorouracil (5-FU) are key drugs against oral cancer chemotherapy. The promising clinical activity of TXT and 5-FU has promoted considerable interest in combining these drugs. Although the combination treatment has been reported to improve the response rates, sequential treatment with TXT and 5-FU was unknown.

[Purpose] The aim of this study was to evaluate the anti-tumor effects of sequential treatment with TXT and 5-FU against oral squamous cell carcinoma cells.

[Methods and Results] Two human oral squamous cell carcinoma cell lines, B88 and CAL27 cells were used in this study. The effects of sequential treatment on the inhibition of tumor growth with TXT and 5-FU were investigated by 3-(4, 5-dimethylthiaol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometric analysis, and the xenograft on nude mice. In vivo study, B88 or CAL cells (5×106) were subcutaneously inoculated into the backs of nude mice. When the tumor reached 0.5 cm in diameter, tumor-bearing nude mice received either the intraperitoneal administration of TXT (10 mg/kg) alone, 5-FU (15 mg/kg) alone, TXT followed by 5-FU or 5-FU followed by TXT treatment. TXT followed by 5-FU treatment more effectively inhibited the tumor growth in vitro and in vivo, and induced apoptosis than 5-FU followed by TXT treatment. To elucidate the mechanisms underlying growth inhibitory effect of TXT followed by 5-FU, we examined the expression of 5-FU metabolic enzymes, thymidylate synthase (TS), dehydropyrimidine dehydrogenase (DPD), and ortate phosphorybosyl transferase (OPRT) by real-time PCR and western blot analysis. Down-regulation of TS and DPD expression, and up-regulation of OPRT expression were induced by TXT treatment compared with 5-FU, suggesting that they enhanced the efficacy of 5-FU.

[Conclusions]These findings demonstrated that sequential treatment with TXT followed by 5-FU can be effective for the patients with oral squamous cell carcinoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3640.
Abstract 3660: Bicarbonate attenuates irinotecan-induced cytotoxicity by altering intracellular pH in HT29 cells
Authors: Miyazaki Teruo , Saitoh Erika , Nagai Yoshiaki , Ikegami Tadashi , Matsuzaki Yasushi , Kobayashi Kunihiko , Bouscarel Bernard E.
Published: February 2011

[Background/Aim] The therapeutic efficacy of irinotecan (CPT-11) is often limited by the induction of severe late-onset diarrhea. CPT-11 and its active metabolite (SN-38) have a labile α-hydroxy-lactone ring that undergoes pH-dependent reversible hydrolysis, and the toxicity is more potent in the lactone (LA) form at acidic pH compared to that in the carboxylate (CA) form in physiological and higher pH. We have previously demonstrated that sodium bicarbonate (Bicarb) reduced the intestinal toxicity of CPT-11/SN-38 in in vivo, in a mouse model, and in a cultured intestinal cancer (HT29) cell line. The hypothesis was that protective action of Bicarb might be due, at least in part, to reduced CPT-11/SN-38-induced intracellular (pHi) acidification.

[Method] HT29 cells were exposed to ∼1µM SN-38 LA or CA form for 2h and further incubated in fresh medium at two different extracellular pH (6.2 and 7.4) adjusted by HCl with 44 mM Bicarb for an additional 96h. In addition, the HT29 cells exposed to SN-38 LA were also incubated at 5-set points of extracellular pH at 6.8, 7.0, 7.4, 7.8, 8.2 adjusted by either increasing concentrations of Bicarb (5, 10, 20, 44, 100mM, respectively) or HCl/NaOH in combination with Trice, Tris, and NaH2PO4 to maintain extracellualr pH during culture. The cell proliferation and apoptosis were examined by MTT assay and Flow Cytometry, respectively. The pHi following SN-38 exposure was also analyzed using Snarf-1 with two concentrations (10 and 30mM) of Bicarb.

[Result] The cell proliferation was significantly decreased on exposure to SN-38 LA form compared to the CA form, while there was no difference in the lower cell growth on exposure to LA form between pH 6.2 and 7.4. In the SN-38 exposed cells, the cell proliferation and apoptosis were significantly higher and lower, respectively, dependent on the concentration of Bicarb. However, the decreased cell viabilities were not influenced by extracellular pH without Bicarb. The SN-38 LA exposure induced a significant decrease of pHi, and the incubation with 30mM Bicarb significantly prevented from the acidification of pHi compared to that in 10mM Bicarb.

[Conclusion] The present study showed that cell cytotoxicity of SN-38 was independent of extracellular pH but dependent on pHi that converts the SN-38 form, while the acidification of pHi was reduced by Bicarb. The novel protective mechanism of Bicarb action against intestinal cell injury by CPT-11/SN-38 would be beneficial for anti-cancer therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3660.
Abstract 3666: Follicle-stimulating hormone inhibits apoptosis and autophagy in ovarian cancer cells by activating survivin and Rab25
Authors: Liu Yingtao , Huang Yan , Jin Hongyan , Cheng Kwai Wa , Lu Yiling , Yu Yinhua , Feng Youji
Published: February 2011

Follicle-stimulating hormone (FSH) has been demonstrated to increase the risk of ovarian malignancy, but the mechanisms remains unclear. Our previous results showed that FSH increases the expression of VEGF through activation of survivin, which is mediated by the activation of the PI3K/AKT signaling pathway. We reported, herein, that FSH promoted ovarian cancer cells proliferation and prevented apoptosis in vitro and in vivo. FSH up-regulated the expression of survivin and down-regulated the expression of programmed cell death 6 (PDCD6) and death receptor 5 (DR5), two molecules required for apoptosis induction. Further, we have defined that the decreased expression of DR5, but not PDCD6, was mediated by survivin. We have established animal xenografts tissue arrays, the tumors from the groups with FSH treatment had higher expression of survivin and lower expression of DR5 comparing with the tumors from untreated groups, further confirming the interaction of FSH-survivin-DR5. In addition, we have demonstrated that FSH does not only inhibit apoptosis, but also inhibit autophagy. FSH inhibits autophagy by activating mTOR pathway in ovarian cancer cells under different stress conditions, including serum starvation. By Reverse Phase Protein Arrays (RPPA) analysis and western blot confirmation, we found that FSH stimulation increases the level of Rab25 in multiple ovarian cancer cells in a dose dependent manner. Rab25, a small GTPase, is found to be associated with the progression of ovarian tumor. Rab25, belongs to Rab11 supfamily, was shown to involve in endosomal recycling. To study the role of FSH-Rab25 interaction in regulating autophagy, we knocked down Rab25 expression in ES-2, Hey and SKOv3 ovarian cancer cell lines by siRNA, and examined the effects of FSH on autophagy. Rab25 knockdown increased the starvation induced autophagy through the inhibition of pAkt, while FSH administration could partly reverse the effects of Rab25 knockdown, due to the increase of Rab25 expression stimulated by FSH. Our findings indicated that Rab25 is one of the molecules regulated by FSH in ovarian cancer cells that has a novel role as a regulator in autophagy. Taken together, we have demonstrated that FSH promotes ovarian cancer development through regulating expression of survivin, Rab25, PDCD6 and DR5, which in turn regulates cell proliferation, apoptosis as well as autophagy. Further understanding the molecular mechanisms of FSH in the process of ovarian carcinogenesis and development will ultimately help developing an effective cancer prevention method, and find a novel targeted therapy for ovarian cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3666.
Abstract 3671: First-line treatment of patients with disseminated poorly differentiated neuroendocrine carcinomas with carboplatin, etoposide, and vincristine
Authors: Andresen Marie T. , Knigge Ulrich , Hansen Carsten Palnæs , Hasselby Jane Preuss , Langer Seppo W.
Published: February 2011

Background:

The poorly differentiated neuroendocrine carcinomas (PDEC) represent a highly malignant tumor with an immense tendency to metastasize and a poor prognosis, with a median survival of approximately 6 months without treatment. Treatment based on platin and etoposide is widely recommended as palliative chemotherapy and corresponds to the treatment of extensive stage small cell lung cancer. The recommendation is based on relatively few, older studies, which did not use the 2000 WHO tumor classification, and no controlled, randomised studies have been published.

Method:

Successive chemonaïve patients with disseminated PDEC (small cell carcinomas excluded) allocated for treatment from May 2007 to June 2008 were identified. Patients received carboplatin AUC 5 IV day 1 + etoposide 100 mg/m2 PO day 1-3, and vincristine 1.3 mg/m2 (maximum 2.0 mg) IV day 1. Treatment was repeated every 3 weeks until progression or intolerable toxicity up to a maximum of 6 courses.

Results:

Twenty-two patients diagnosed with PDEC according to the 2000 WHO tumor classification were eligible for analysis, 11 females and 11 males. The median age was 61 years (range 35-80). Performance status: 0/1/2 = 9/11/2. All patients had disseminated disease. Immunohistochemical analyses of synaptophysin were positive in 21/22 (95.4%), and chromogranin A positive in 17/21 (80.9%). In one patient (4.5%) both analyses were negative; in 17/21 (80.9%) both were positive. The Ki-67 proliferation index ranged from 20% to 100%; the index reaching 50% or higher in 17 patients (77.2%). Octreotide scintigraphy was negative in 10 of 12 scanned patients (83,3%). Three patients (13.6%) achieved complete response (CR), 11 (50%) partial response (PR), 4 (18.2%) no change (NC), and 4 (18.2%) progressive disease (PD). The overall response rate (CR+PR) was 63.6%, and the disease control rate (CR+PR+NC) 81.8%. The median progression free survival time was 7.4 months. The median overall survival time was 10.5 months, and the 1-year survival 48%.

Conclusion: In conclusion, treatment with carboplatin, etoposide, and vincristin in previously untreated patients with disseminated PDEC results in a noticeable survival benefit compared to untreated historical controls. The prognosis is however still poor.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3671.
Abstract 3686: Antibody-functionalized single-walled carbon nanotubes for detection and selective destruction of breast and pancreas cancer cells
Authors: Xiao Yan , Gao Xiugong , Cheung William , Urbas Aaron , Taratula Oleh , Holbrook David , Cavicchi Richard E. , Souchek Joshua J. , Wagner Paul D. , Srivastava Sudhir , Avedisian Thomas , He Huixin , Batra Surinder
Published: February 2011

Nanocarrier-based antibody targeting is a promising modality in therapeutic and diagnostic oncology. Single-walled carbon nanotubes (SWNTs) exhibit two unique optical properties that can be exploited for such applications, i.e., strong Raman signal for cancer cell detection and near-infrared (NIR) absorbance for selective photothermal ablation of tumors. In the present study, we constructed a HER2 IgY-SWNT complex and a MUC4 IgG-SWNT complex, and demonstrated in vitro their dual functionality for both detection and selective destruction of breast and pancreas cancer cells.

The two complexes were constructed by covalently conjugating carboxylated SWNTs with anti-HER2 chicken polyclonal IgY antibody and with anti-MUC4 mouse monoclonal IgG antibody, respectively. Raman signals were recorded on a Raman spectrometer with a laser excitation at 785 nm. NIR irradiation was performed using a diode laser system, and cells with or without nanotube treatment were irradiated by 808 nm laser at 50 W/cm2 for 5 min. Cell viability was examined by calcein AM/ethidium homodimer-1 (EthD-1) staining.

Immunohistochemical studies showed that HER2 IgY-SWNT complex specifically targeted receptor-expressing SK-BR-3 cells but not receptor-negative MCF-7 cells; MUC4 IgG-SWNT complex specifically targeted pancreatic cancer cells but not normal pancreas cells. Using a Raman optical microscope, we found the Raman signal collected at single-cell level from the complex-treated breast or pancreatic cancer cells was significantly greater than that from various control cells. NIR irradiation selectively destroyed the complex-targeted breast and pancreatic cancer cells without harming receptor-free cells. The death rate after NIR irradiation were 94.1% and 96.6% respectively for complex-treated breast and pancreatic cancer cells, but only 1.3% and 1.8% for the untreated controls of the two cancer cell types, respectively.

These results demonstrated that the antibody-SWNT complexes have the potential to detect cancer cells at the early stages of tumor development. In addition, the complexes are potentially useful for selectively killing cancer cells while sparing healthy ones. Thus, the unique intrinsic properties of SWNTs combined with high specificity and sensitivity of antibodies can lead to new strategies for cancer detection and therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3686.