bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1802: Small molecule compound NCI-8 induces mutant p53 degradation via inhibition of the MDM2-Hsp90 axis
Authors: Zhang Shengliang , Zhou Lanlan , Kline Christina Leah B. , Dicker David T. , El-Deiry Wafik S.
Published: May 2015

The tumor suppressor p53 prevents cancer development via regulating cell cycle arrest, cell death, or repair processes. Over 50% of human cancers harbor mutant p53. Mutations in p53 not only abrogate its tumor suppressor function, but also endow mutant p53 with a gain-of-function (GOF), creating a proto-oncogene that contributes to tumorigenesis, tumor progression and chemotherapeutic resistance. Thus, targeting mutant p53 to restore wild-type p53 pathway signaling is an attractive strategy for cancer therapy. We previously reported a novel small molecular compound, NCI-8, which not only restores wild-type p53 signaling, but also depletes mutant p53 protein (Zhang S, Zhou L, Hong B, et al. Cancer Res 2013;73(8 Suppl):Abstract 2171). In this study, we further elucidate the mechanism of the small molecular compound NCI-8-mediated degradation of mutant p53 protein. We found that the small molecule NCI-8 induces mutant p53 protein degradation via the MDM2-ubiquitin-proteasome pathway. NCI-8 exposure leads to phosphorylation of p53 at Thr55. Dephosphorylation of p53 at Thr55 rescues mutant p53 protein from degradation in cells treated with Apigenin, suggesting that phosphorylation at Thr55 is required for mutant p53 protein degradation induced by NCI-8. Hsp90 and hsp70 are two molecular chaperones that stabilize mutant p53 protein by affecting the MDM2 mediated turnover of mutant p53, therefore, we investigated the effect of NCI-8 on the MDM2-hsp chaperone axis. We found that less HSP90 but more MDM2 were bound to mutant p53 in cells treated with NCI-8, suggesting that NCI-8 induces mutant p53 protein degradation through disturbing the MDM2-hsp chaperone axis. Correlated to the degradation of mutant p53 protein, the p73 pathway was activated in response to NCI-8 treatment specifically in mutant p53-expressing colorectal cancer cells. Our results provide a possible mechanism of NCI-8-mediated p73-dependent restoration of the p53 pathway via mutant p53 protein degradation.

Citation Format: Shengliang Zhang, Lanlan Zhou, Christina Leah B. Kline, David T. Dicker, Wafik S. El-Deiry. Small molecule compound NCI-8 induces mutant p53 degradation via inhibition of the MDM2-Hsp90 axis. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1802. doi:10.1158/1538-7445.AM2014-1802
Abstract 1804: New insights in the induction of cell death by the imidazolium based compound YM155
Authors: Danielpour David , Shankar Eswar , Corum Sarah L.
Published: May 2015

The inhibitor of apoptosis protein (IAP) Survivin is robustly over-expressed in a variety of cancers including prostate carcinomas, and has been shown to play pivotal roles in cancer progression and resistance to chemotherapy. The imidazolium based small molecule YM155, which was first identified as a robust suppressor of the Survivin promoter of PC-3 prostate carcinoma and under clinical investigation for the treatment of multiple cancers, is a potent apoptosis inducer of castration-resistant prostate cancer (CRPC) cells. However, the mechanisms by which it inhibits the expression of Survivin and kills cancer cells remain unclear. Here we studied early signaling responses to YM155 in a panel of prostate and kidney cancer cell lines in standard cell culture conditions and showed that YM155 rapidly decreases the expression of cyclin Ds 1, 2 and 3, and activates the retinoblastoma protein (Rb), leading to the downregulation of the Survivin promoter. However, despite the robust lost of cyclin Ds, YM155 promotes an S-phase arrest rather than arrests cells at either G1 or G2/M. This suggests cell killing by YM155 involves S-phase arrest, consistent with a DNA damage response. In addition, we show that YM155 also downregulates the expression of the anti-apoptotic protein Mcl-1 and induces the expression of proapoptotic proteins Bad and Bim followed by the activation of caspases -3 and -8. Moreover, early time course experiments show that YM155 induces rapid (10 - 60 min) but transient activation of Akt and Erk1/2 followed by a marked suppression by 4 to 8 h likely via the induced expression of phosphatases 1 and 5 (DUSP1 and 5). Taken together we suggest YM155 induces apoptosis of prostate epithelial cells through a complex mechanism involving Akt, Erk1/2, DUSPs, cyclin Ds, Rb, S-phase arrest, Bim, Bad, Mcl-1,Survivin, and activation of caspases -3 and -8.

Citation Format: David Danielpour, Eswar Shankar, Sarah L. Corum. New insights in the induction of cell death by the imidazolium based compound YM155. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1804. doi:10.1158/1538-7445.AM2014-1804
Abstract 1805: Characterization of pyoluteorin derivatives as Mcl-1 antagonists
Authors: Doi Kenichiro , Gowda Krishne , Liu Qiang , Sung Shen-Shu , Lin Jyh Ming , Amin Shantu , Loughran Thomas P. , Wang Hong-Gang
Published: May 2015

The evasion of apoptosis is considered to be a hallmark of cancers and a cause of resistance to anti-cancer therapies. Consistently, aberrant overexpression of anti-apoptotic Bcl-2 family proteins (e.g., Bcl-2, Bcl-xL, Mcl-1) is associated with tumorigenesis and increased resistance to chemotherapy in multiple malignancies. To date, several small-molecule Bcl-2 inhibitors that bind the BH3-binding pocket of the protein have entered clinical trials. These BH3 mimetics are known to induce apoptosis by disrupting the interactions between pro- and anti-apoptotic Bcl-2 family proteins. The most well characterized selective agents are the Bcl-2 inhibitor ABT-737 and its orally active analog ABT-263 which inhibit Bcl-2 and Bcl-XL but not Mcl-1. Consequently, cancers with elevated Mcl-1 do not respond to these drugs. Moreover, Mcl-1 is frequently upregulated in cancer cells and compensates for the inhibition of Bcl-2 function by ABT-737, thereby mediating resistance to the drug. Thus, there is an urgent need to develop Mcl-1-specific inhibitors for the treatment of Mcl-1-dependent human cancers. We have recently identified and characterized the natural product marinopyrrole A (maritoclax) as a novel Mcl-1 inhibitor, which induces apoptosis by targeting Mcl-1 for proteasomal degradation without significant effects on mRNA levels. To determine the pharmacophore of maritoclax, we systematically altered or removed portions of the molecule to identify regions essential for inhibition of Mcl-1 and induction of apoptosis. To date, we synthesized over 40 derivatives of maritoclax and evaluated their inhibitory actions toward Mcl-1 and cytotoxicity in cell lines of human hematological malignancies. As a result, we have identified several pharmacophore sites in maritoclax that are required for biological activity and two pyoluteorin derivatives, KS04 and KS18, which bind to a similar site(s) in Mcl-1 as maritoclax, as determined by NMR titration experiments. Like maritoclax, KS04 or KS18 markedly reduced the half-life of Mcl-1 protein, induced apoptosis selectively in Mcl-1-dependent but not Bcl-2-dependent K562 cells, and acted synergistically with ABT-737 to enhance apoptosis in ABT-737 resistant HL60 cells. Moreover, the combination treatment of KS18 (10 mg/kg/d) and ABT-737 (20 mg/kg/d) significantly suppressed the growth of ABT-737-resistant HL60 xenografts in nude mice. Thus, further studies are warranted to develop pyoluteorin derivatives as a novel class of Mcl-1 inhibitors.

Citation Format: Kenichiro Doi, Krishne Gowda, Qiang Liu, Shen-Shu Sung, Jyh Ming Lin, Shantu Amin, Thomas P. Loughran, Hong-Gang Wang. Characterization of pyoluteorin derivatives as Mcl-1 antagonists. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1805. doi:10.1158/1538-7445.AM2014-1805
Abstract 1821: HER3 activation by MET contributes to trastuzumab resistance in HER2-positive breast cancer
Authors: Hashimoto Kenji , Macaulay Valentine , Kong Anthony
Published: May 2015

Background: Trastuzumab is a standard therapy for HER2-positive breast cancer patients. Majority of the patients treated with trastuzumab in metastatic disease experience relapse. MET has been reported as one possible candidate of trastuzumab resistance however, detailed mechanism is unclear.

Methods: Using panel of HER2-positive cell lines, pHER3 level was assessed with trastuzumab treatment by western blot. Co-immunoprecipitation and siRNA knockdown were used to assess the interaction between HER3 and MET.

Results: Phospho-HER3 as well as pAKT levels were decreased after trastuzumab treatment in trastuzumab sensitive cell lines, while there were no deactivation in the resistant cell lines. In the primary trastuzumab resistant cell lines, 5 of 6 cells expressed MET while only one of 4 cells expressed MET in the sensitive cell lines. BT474 cells were found to have increased MET level when the cells acquired resistance to trastuzumab. HCC1954 cells, MET overexpressing and primary trastuzumab cell line, were sensitized to trastuzumab when MET was knocked down. MET knockdown led to a decrease of phosphor-HER3 level in HCC1954, BT474, and BT474 trastuzumab resistant (BT-TR) cells. The paraffin-embedded tumor samples from BT474 xenograft treated with trastuzumab and HER2-positive breast cancer patients will be stained for MET expression to assess its prognostic and predictive values sin HER2 positive breast cancer.

Conclusion: MET may play a key role in maintaining HER3 phosphorylation during trastuzumab treatment and resistance in HER2 positive breast cancer.

Citation Format: Kenji Hashimoto, Valentine Macaulay, Anthony Kong. HER3 activation by MET contributes to trastuzumab resistance in HER2-positive breast cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1821. doi:10.1158/1538-7445.AM2014-1821
Abstract 1831: Interrogating HER2+ plasticity and lapatinib resistance with MicroEnvironment MicroArrays
Authors: Watson Spencer , Korkola James , Rantala Juha , Gray Joe
Published: May 2015

Treatment of HER2+ breast cancer with the targeted therapeutic lapatinib has shown promising results, but faces the major obstacles of de novo and acquired resistance in clinical use. Much of this resistance can be attributed to intratumoral heterogeneity, giving rise to drug resistant cell populations. An important factor of intratumoral heterogeneity is spatial heterogeneity of cancer cells, which results in differential contact with extra cellular matrix (ECM) proteins, stromal cells, and growth factors and signaling molecules within the tumor microenvironment. This can variably alter the intracellular signaling network of cancer cells, modulating cellular plasticity and drug response.

To assess the effect cellular interactions with the microenvironment has on lapatinib resistance, we are utilizing MicroEnvironment MicroArrays (MEMA), which consist of combinations of functional ECMs, growth factors, and cytokines printed onto a solid surface, allowing for the simultaneous interrogation of thousands of unique microenvironments in a single assay. We have grown HER2+ breast cancer cells on the MEMA spots, treated with lapatinib, and measured functional response to each protein combination by immunofluorescent assay and high throughput image acquisition and analysis. By focusing on markers of proliferation, apoptosis, and cellular subtype differentiation, we have identified protein combinations that confer resistance to lapatinib. One of the combinations that came out of this preliminary screen is the desmosome protein Desmoglein II and the growth factor HGF, which continued to drive proliferation of HER2+ cells in the presence of lapatinib. Validation experiments found that on their own these two proteins could modulate the differentiation status of HER2+ cells, and combined to provide resistance to lapatinib treatment in traditional cell culture assays. In addition, the extent of drug resistance provided by protein interaction was found to be strongly linked to the differentiation status of the HER2+ cells. Both HGF and Desmoglein II are reported to be important in the progression of breast cancer, but their effect in combination is a novel finding from the use of MEMA analysis.

We plan to utilize RNAseq analysis to inform a probabilistic computational model of network signaling to determine what pathways are enhanced by the microenvironment factors, and siRNA knockdown or small molecule inhibitors of identified pathway nodes can then determine which interactions can be targeted to restore drug sensitivity.

Citation Format: Spencer Watson, James Korkola, Juha Rantala, Joe Gray. Interrogating HER2+ plasticity and lapatinib resistance with MicroEnvironment MicroArrays. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1831. doi:10.1158/1538-7445.AM2014-1831
Abstract 1844: Novel HER3 neutralizing antibody, patritumab abrogates cetuximab resistance mediated by a heregulin-autocrine loop in colorectal cancer
Authors: Kawakami Hisato , Okamoto Isamu , Yonesaka Kimio , Okamoto Kunio , Kuwata Kiyoko , Morita Yume , Yamaguchi Haruka , Nishio Kazuto , Nakagawa Kazuhiko
Published: May 2015

Purpose

Acquired resistance to cetuximab is a major problem in the treatment of colorectal cancers. We previously showed that the HER3/HER4 ligand heregulin induced resistance to cetuximab by increasing the association between HER2 and HER3, and subsequent activation of downstream targets. We have now investigated strategies to overcome such resistance, using patritumab, a novel neutralizing HER3 antibody.

Experimental design

We established DiFi cells that stably express heregulin (DiFi-HRG cells) as a result of retroviral infection, and examined the antitumor effect of cetuximab, patritumab, and the combination of both in these cells in vitro and vivo.

Results

DiFi-HRG cells secreted large amount of heregulin and exhibited resistance to cetuximab. Cetuximab alone down-regulated ERK phosphorylation, whereas it had no effect on AKT phosphorylation, suggesting that continuous AKT activation underlain underlies resistance to cetuximab in these cells. In contrast, Patritumab in combination with cetuximab markedly reduced the level of phosphorylation of HER2 HER3 and AKT, as well as ERK, and induced apoptosis that was accompanied by upregulation of BIM and by downregulation of survivin in vitro. Furthermore, the combination therapy also markedly inhibited the growth of DiFi-HRG tumors in nude mice to a greater extent than did treatment with either drug alone.

Conclusion

Our data indicate that HER2/HER3 signaling activated by a heregulin-autocrine loop confers resistance to cetuximab, and that patritumab restored sensitivity to cetuximab by inhibition of HER3 phosphorylation that is stimulated by heregulin.

Citation Format: Hisato Kawakami, Isamu Okamoto, Kimio Yonesaka, Kunio Okamoto, Kiyoko Kuwata, Yume Morita, Haruka Yamaguchi, Kazuto Nishio, Kazuhiko Nakagawa. Novel HER3 neutralizing antibody, patritumab abrogates cetuximab resistance mediated by a heregulin-autocrine loop in colorectal cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1844. doi:10.1158/1538-7445.AM2014-1844
Abstract 1864: Reptin as a tumor-associated antigen of epithelial ovarian cancer
Authors: Lee Eun-ju , Cho Hanbyoul , Shin Ha-Yeon , Yang Wookyeom , Kwon Hyunja , Kim Sol , Kim Jae-Hoon
Published: May 2015

Background:

Reptin is also known as RuvBl2, Tip48, TIP49b, ECP51 and CGI-46, is a member of AAA+ (ATPases associated with diverse cellular activities) superfamily. Reptin is associated with cell viability and development of S. cerevisiae, D. melanogaster, X. laevis, or D. rerio has a lot of functions including transcriptional regulation, DNA damage repair and telomerase activity.

Self-reactive IgG autoantibodies are present on human sera.Each self-reactive IgG autoantibody derived from pre- and post-treatment of ovarian cancer patients is competitively combined with cancer tissue gotten during the operation, self-reactive IgG autoantibodies bound to tumor antigens. As a result, self-reactive IgG autoantibodies may be decreased after treatment. In this study, we have identified and investigated the function of Reptin as an available therapeutic biomarker for ovarian cancer using difference of self-reactive IgG autoantibody amounts.

Method:

We carried out the two-dimensional differential gel electrophoresis analysis of immunoprecipitated tumor antigens (2D-DITA) to compare with expression level of autoantibodies in pre- and post-treatment sera of 14 ovarian cancer patients. Autoantibody differentiated between pre- and post-treatment sera was identified by MALDI-TOF.

We performed qRT-PCR with 8 human ovarian surface epitheliums (HOSEs) and 14 ovarian cancer cell lines for validation studies. Reptin was also detected in other ovarian cancer tissues by immunohistochemistry (IHC). We constructed SKOV-3 cell line for overexpression Reptin using lentiviral system. For investigating function of Reptin, we performed proliferation, wound healing, and invasion assay.

Results:

We identified Reptin as a tumor-associated antigen of epithelial ovarian cancer. Relative mRNA level of Reptin showed higher levels in ovarian cancer cell lines than in HOSEs. Reptin protein levels were significantly upregulated in ovarian cancer tissues than normal, benign, and borderline ovarian tumors. In SKOV-3 cells, overexpression of Reptin induced inhibition of cell proliferation (P<0.0001), migration and invasion (P<0.0001).

Conclusion: Our results demonstrate that Reptin is a tumor -associated antigen of ovarian cancer, i.e. tumor suppressor.

Citation Format: Eun-ju Lee, Hanbyoul Cho, Ha-Yeon Shin, Wookyeom Yang, Hyunja Kwon, Sol Kim, Jae-Hoon Kim. Reptin as a tumor-associated antigen of epithelial ovarian cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1864. doi:10.1158/1538-7445.AM2014-1864
Abstract 1872: A novel method for efficient and hands-free purification of circulating DNA from human plasma
Authors: White Douglas , Horejsh Douglas , Zeng Zhiyang , Uyeda Tetsuo , Meisenheimer Poncho , Urh Marjeta
Published: May 2015

Circulating or Cell-Free DNA in plasma can be used to detect biomarkers that show great promise for diagnosis and monitoring of cancer, and is already being used as a non-invasive method to detect trisomy in fetuses. There is currently great interest in the discovery of new cancer biomarkers and their potential clinical application. However, reproducible and efficient purification of these highly fragmented and low-concentration species represents a major challenge. Here we will present a novel method which is completely automated and allows parallel purification of circulating nucleic acid from plasma and serum using a medium-throughput robot. Sixteen samples can be processed simultaneously. The method was optimized to produce high-quality DNA that is suitable for use in quantitative PCR and next generation sequencing. In addition, the absence of any pre-processing steps improves reproducibility and lowers the risk of contamination.Initial characterization on plasma from pregnant women showed that fetal DNA could be detected as early as 4 weeks into gestation and could be tracked throughout pregnancy. Further characterization showed that the system was able to reliably detect less than 25 copies/ml plasma of fragmented DNA that was spiked into the sample. Subsequent work on plasma from patients with colorectal cancer showed that the system was able to detect DNA containing both wild-type and mutated EGFR, suggesting that this method can be a useful tool when screening plasma samples for biomarkers of interest.

Citation Format: Douglas White, Douglas Horejsh, Zhiyang Zeng, Tetsuo Uyeda, Poncho Meisenheimer, Marjeta Urh. A novel method for efficient and hands-free purification of circulating DNA from human plasma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1872. doi:10.1158/1538-7445.AM2014-1872
Abstract 1886: Highly sensitive detection of circulating tumor DNA in plasma as a biomarker of colorectal cancer
Authors: Wiggin Matthew , Perkins Jaryn , Mai Laura , Vysotskaia Valentina , Marziali Andre
Published: May 2015

Circulating tumor DNA (ctDNA) from the blood of cancer patients is a promising biomarker of certain types of colorectal cancer, with potential use in screening, treatment selection, therapy response monitoring, minimal residual disease detection, and surveillance.

We present results demonstrating that the OnTarget ctDNA detection assay can be used as an indicator of the presence of genomic variants associated with colorectal cancer in patients prior to treatment. The study includes three cohorts of individuals: young normal controls, age-matched normal controls, and colorectal cancer patients whose blood was drawn prior to treatment or surgery, and whose diagnosis confirms the presence of a colorectal tumor. Tissue from the primary tumor biopsy was also collected and analyzed with the OnTarget assay.

Using Boreal Genomics' OnTarget 46-mutation panel, we find high correlation between the tumor mutational profile and the plasma mutation profile even for early stage patients demonstrating high sensitivity (88% plasma-tissue concordance to date) of the assay. By applying the same assay in the normal population we demonstrate extremely low false positive rates, highlighting the potential of the assay as a tool for therapy monitoring, surveillance, or screening.

The OnTarget assay is capable of single molecule sensitivity, specificity to ≤0.01% mutation abundance versus wild-type, and multiplexing of over 100 mutations in a single test from a single plasma sample. The OnTarget technology employs a combination of Next Generation DNA Sequencing and a proprietary target selection process that removes wild-type DNA prior to amplification to greatly improve signal to noise and reduce the error rate of sequencing.

We present an overview of the technology and results from an ongoing study to demonstrate the potential clinical utility of ctDNA as an effective biomarker to guide management of colorectal cancer.

Citation Format: Matthew Wiggin, Jaryn Perkins, Laura Mai, Valentina Vysotskaia, Andre Marziali. Highly sensitive detection of circulating tumor DNA in plasma as a biomarker of colorectal cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1886. doi:10.1158/1538-7445.AM2014-1886
Abstract 1896: Clinicopathologic characteristics for elevated microsatellite alterations at selected tetranucleotie repeats (EMAST) in colorectal cancer of Korean patients
Authors: Ihn Myong Hoon , Kim Duck-Woo , Lee Hye Seung , Park Kyoung Un , Lee Soo Young , Oh Heung-Kwon , Kang Sung-Bum
Published: May 2015

Microsatellite instability (MSI) is a hallmark of tumors with mismatch repair deficiency. Recently, a different type of instability, elevated microsatellite alterations at selected tetranucleotide repeats (EMAST) has been reported in colorectal cancers. EMAST was reported to be associated with various clinicopathologic characteristics, including MSI status, race, tumor progression, and morphology and differentiation of tumor. However, contrary to MSI status which is well known prognostic and predictive marker in CRC, clinical implication of EMAST in CRC is still unclear. We evaluated EMAST and MSI status in 88 sporadic CRC cases using five markers (MYCL1, D9S242, D20S85, D8S321, and D20S82) for EMAST and Bethesda panel for MSI status, respectively. Clinicopathologic data of the patients were collected and analyzed. Tumors showing frameshifts in at least two or more EMAST markers were classified as EMAST-positive. Among 88 tumors, EMAST-positive tumors were 22 (25.0%) and MSI-H tumors were 32 (36.4%). EMAST-positive tumors showed proximal location of tumor (90.9% vs. 66.7%, p=0.029), less frequent loss of thymidylate synthase expression (4.5% vs. 34.8%, p=0.005), MSI-H (81.8% vs. 21.2%, p<0.001), nuclear heterogeneity of hMSH3 expression (77.3% vs. 51.5%, p=0.046) when compared with non-EMAST tumor. The other variables including age, gender, gross type and differentiation of tumor, a presence of stromal reaction, and tumor stage were not associated with EMAST status. In addition, overall and disease-free survival rate were similar between EMAST and non-EMAST tumor. In this study, MSI-H tumors showed very high frequency of EMAST-positive and clinical characteristics of EMAST and non-EMAST tumor were definitely different.

Citation Format: Myong Hoon Ihn, Duck-Woo Kim, Hye Seung Lee, Kyoung Un Park, Soo Young Lee, Heung-Kwon Oh, Sung-Bum Kang. Clinicopathologic characteristics for elevated microsatellite alterations at selected tetranucleotie repeats (EMAST) in colorectal cancer of Korean patients. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1896. doi:10.1158/1538-7445.AM2014-1896
Abstract 1903: Personalized diagnostics: Receptor specific gold nanorods used for accurate diagnosis of EGFR expression in human tumor tissues
Authors: Caldwell Chuck , Zambre Ajit , Suresh Dhananjay , Arthur Gerald , Kannan Raghuraman
Published: May 2015

Objective: The purpose of this study was to apply the enhanced surface chemistry and imaging properties of gold nanorods to the area of tumor protein diagnostics in order to give an accurate, quantifiable interpretation of a patient's biomarker status. The epidermal growth factor receptor (EGFR; HER1) is a cell surface receptor that regulates cell migration, adhesion, and proliferation. EGFR is commonly overexpressed in a variety of cancers. EGFR expression testing has been mandated by insurance companies in many areas before therapy can be given. Current methods of EGFR evaluation have been shown to be unreliable, thus EGFR was chosen as a target of interest for our studies.

Methods: Gold nanorods (GNR) of aspect ratio 3:4 were prepared using an established seed-mediated growth method. The GNR were then PEGylated and conjugated with a unique modified peptide that has shown specific affinity for the EGF receptor. The product was characterized to show stability and presence of surface-bound peptide. The compound known as GNR-1070 was used to examine correlations between EGFR expression and gold present on the membranes of human cell lines and paraffin-embedded tissue samples.

Results: In cell lines that are known to express EGFR, gold particles were identified bound to the membranes. The amount of bound gold correlated with the degree of EGFR expression of each cell line. Histochemical analysis of paraffin-embedded human tissue lines also correlated with the amount of gold bound to the membranes of the tissues.

Conclusion: Gold nanorods conjugated with receptor-specific peptides can be used to give an accurate evaluation of protein expression in human cell lines and tissue samples.

Citation Format: Chuck Caldwell, Ajit Zambre, Dhananjay Suresh, Gerald Arthur, Raghuraman Kannan. Personalized diagnostics: Receptor specific gold nanorods used for accurate diagnosis of EGFR expression in human tumor tissues. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1903. doi:10.1158/1538-7445.AM2014-1903
Abstract 1914: Functional characterization of oncogenic-induced dedifferentiation in neurons and astrocytes using DP-seq
Authors: Friedmann-Morvinski Dinorah , Bhargava Vipul , Gupta Shakti , Verma Inder M. , Subramaniam Shankar
Published: May 2015

Glioblastoma (GBM) is the most common and lethal form of intracranial tumor. Using a Cre-inducible lentiviral GBM mouse model we recently showed that gliomas can originate from dedifferentiation of mature neurons and astrocytes. Expression analysis of the known markers (of the differentiated cell-types) showed diminished expression while the expression of the undifferentiated state markers were significantly up-regulated in the dedifferentiated transformed neurons and astrocytes. In this study, we performed whole transcriptome analysis of these cells along with mouse pluripotent embryonic stem cells (mESC), neural stem cells (NSC), neurons and astrocytes to characterize the undifferentiated state of these cells. Our analysis revealed that dedifferentiated cell-types shared traits with neurons and NSCs at the global transcriptome level suggesting that they have retained memory of their cell-of-origin and share markers of undifferentiated cells with NSCs. Functional analysis of the transcriptomics data revealed involvement of the Wnt signaling, cell cycle and the focal adhesion pathways in defining the state of the dedifferentiated cell-types. Our analysis further revealed conservation of a gene interaction network in both dedifferentiated cell-types. This network exhibited a modular architecture, connecting components of the cell cycle pathway to Wnt signaling and the focal adhesion pathways. One of these components, Osteopontin (OPN), also known as Spp1, is highly expressed and secreted by the tumors and dedifferentiated transformed neurons and astrocytes. Attempts to inhibit the action of OPN, either by using a neutralizing antibody or silencing the OPN gene (shRNA), blocked the formation of tumorspheres and diminished their proliferating capacity. We are currently assessing the effects of the inhibition of OPN function in vivo.

Further genetic perturbation of additional interacting partners and/or the abolishment of the interactions can help elucidate the regulatory mechanism of this network in maintaining the dedifferentiated state of the transformed neurons and astrocytes.

Citation Format: Dinorah Friedmann-Morvinski, Vipul Bhargava, Shakti Gupta, Inder M. Verma, Shankar Subramaniam. Functional characterization of oncogenic-induced dedifferentiation in neurons and astrocytes using DP-seq. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1914. doi:10.1158/1538-7445.AM2014-1914
Abstract 1917: Re-thinking the concept of cancer stem cells: Polyploid giant cancer cells as mother cancer stem cells
Authors: Liu Jinsong , Mercado-Uribe Imelda , Niu Na , Sun Baocun , Kuang Jian , Zhang Shiwu
Published: May 2015

Polyploid giant cancer cells (PGCCs) have been observed by pathologists for over a century. PGCCs contribute to solid tumor heterogeneity, but their functions are largely undefined. Little attention has been given to these cells, largely because PGCCs have been generally thought to originate from repeated mitosis/cytokinesis failure and have no capacity for long-term survival and cell proliferation. Our group has recently reported that we successfully purified and cultured PGCCs from human ovarian cancer cell lines and primary ovarian cancer. These cells are highly resistant to oxygen deprivation and could form through endoreduplication or cell fusion, generating regular-sized cancer cells quickly through budding or burst. They are positive for normal and cancer stem cell markers, divided asymmetrically and cycled slowly. They can differentiate into adipose, cartilage, and bone. A single PGCC formed cancer spheroids in vitro and generated tumors in immunodeficient mice. PGCC-derived tumor gained a mesenchymal phenotype with increased expression of cancer stem cell markers CD44 and CD133 and become more resistant to the treatment of cisplatin and also form tissue organ-like structure. Together, our results reveal that the PGCCs present a resistant form of human cancer that behaves like mother cancer stem cells that can contribute to generation of daughter cancer stem-like cells and formation of tissue organ structure. These cells can be induced in response to hypoxia and play a fundamental role in regulating tumor heterogeneity, stemness, and chemoresistance in human cancer. In contrast to the phenotype unstable cancer stem cells selected by cell surface markers, PGCCs can be stably passaged and maintained, thus these cells provide reproducible experimental system to study mechanisms involved in generation of cancer stem cells. The key references related this concept are listed below. we will provide a most updated data to support this new concept that PGCCs as mother cancer stem cells at this meeting.

Zhang S et al, Oncogene 2013, March online publication; Zhang S et al, Int J Cancer. 2013 Feb 1;134(3):508-18; Zhang S el al, Cancer Lett. 2013 Jun 10;333(2):205-12.

Citation Format: Jinsong Liu, Imelda Mercado-Uribe, Na Niu, Baocun Sun, Jian Kuang, Shiwu Zhang. Re-thinking the concept of cancer stem cells: Polyploid giant cancer cells as mother cancer stem cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1917. doi:10.1158/1538-7445.AM2014-1917
Abstract 1918: Synergy between epithelial and mesenchymal cells in breast cancer: from mammospheres to predicting patient outcomes
Authors: Grosse-Wilde Anne , d'Herouel Aymeric , Kuestner Rolf , Ertaylan Gokhan , Skupin Alexander , Huang Sui , Ozinsky Adrian
Published: May 2015

Targeting breast cancer stem cells promises to eliminate the root of metastasis and recurrence and thus to eradicate the ultimate cause of cancer-related death of patients. However, the identity of epithelial cancer stem-like is still elusive; cancer stem-like and metastasis initiating cells have been described to be either epithelial (E) or mesenchymal (M), and thus their identity appears to critically depend on the context of the analyzed cell line.

Here, we have studied the heterogeneous HMLER cell line to identify the relationships between epithelial and mesenchymal cells while they are differentiated and selected under suspension culture conditions. We find that CD24+/CD44- epithelial cells and CD44+/CD24- mesenchymal cells synergize in causing the proliferation of both sub-populations, increasing mammosphere production, and causing the emergence of aggressive motile cells when replated. We observed that when grown in suspension, isolated epithelial as well as isolated mesenchymal cell populations converged towards a hybrid E/M state characterized by coexpression of genes of both lineages, from population down to the single cell level. For epithelial populations convergence at the hybrid state during growth in suspension was thus achieved by proliferation of the most mesenchymal cells resembling an epithelial to mesenchymal transition at the population level. For mesenchymal populations, the hybrid state was reached by the reverse, MET, involving proliferation of the most epithelial cells in a context dependent manner.We use these findings to resolve which genes are predictive of poor outcome in primary human breast tumors. Here we show for the first time that high expression of mesenchymal genes in luminal B/epithelial tumors predicts poor outcome of patients, whereas expression of epithelial genes in basal/mesenchymal tumors predicts poor outcome and thus increased metastasis. Therefore, functional synergy between E and M cells can explain how the tumor context determines whether a minority of mesenchymal or epithelial cells can serve as metastatic stem cells.

Citation Format: Anne Grosse-Wilde, Aymeric d'Herouel, Rolf Kuestner, Gokhan Ertaylan, Alexander Skupin, Sui Huang, Adrian Ozinsky. Synergy between epithelial and mesenchymal cells in breast cancer: from mammospheres to predicting patient outcomes. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1918. doi:10.1158/1538-7445.AM2014-1918
Abstract 1923: NF-κB signaling supports a sub-population of ovarian cancer tumor-initiating cells
Authors: House Carrie D. , Annunziata Christina M.
Published: May 2015

Although most patients respond favorably to first-line chemotherapy, ovarian cancer remains the most lethal gynecological cancer in the United States primarily because of a high incidence of disease recurrence. The inability of traditional chemotherapy to eradicate tumor-initiating cells (TICs) is a plausible explanation for tumor relapse and we have begun to characterize TIC populations in ovarian cancer cell lines. Importantly, we are investigating the role of the NF-κB pathway in regulating this system. We have identified conditions that sustain a highly tumorigenic TIC population. Preliminary data suggest that NF-κB promotes and sustains TICs in ovarian cancer and current efforts are underway to characterize the molecular mechanisms underlying this preference. We will correlate activity of this pathway with expression of ovarian TIC protein markers such as CD133, Sox2, Nanog, and Oct-4 in TIC cell cultures and xenografts. Moreover we will use TICs to investigate effects of inhibiting this pathway on marker expression, proliferation, resistance to chemotherapy, and the ability to form tumors in mice. Clarifying the specific role of the NF-κB network in TIC populations will further our understanding of ovarian cancer initiation, progression, and relapse and may lead to improved therapeutic strategies for women in first remission, to prevent subsequent relapse to incurable disease.

Citation Format: Carrie D. House, Christina M. Annunziata. NF-κB signaling supports a sub-population of ovarian cancer tumor-initiating cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1923. doi:10.1158/1538-7445.AM2014-1923
Abstract 1926: Identification of stem cell by immunohistochemistry in benign and malignant human esophageal mucosa
Authors: Vaiphei Kim , Sinha Saroj Kant , Kochhar Rakesh
Published: May 2015

Introduction: Esophageal squamous cell carcinoma (ESCC) response to treatment if still unsatisfactory with high mortality rate. Objective: to identify the role of cancer stem cell in ESCC by studying the tumor by immunohistochemistry, with the concept of identifying the possible cell for the progression of the tumor due to its uncontrolled proliferation. Materials and methods: endoscopic biopsy and resected specimens of confirmed ESCC tissue were used for the study - fresh tumor tissue with no treatment, post treated residual tumor tissue, recurrent tumor tissue and adjoining esophageal mucosa. Primary immunomarkers used in the study were : i) alpha 6 integrin, ii) CD71, iii) p63, iv) stem cell antigen1, v) cytokeratin 6, vi) Bim1, vii) oct4, viii) nucleostemin, ix) Ki67, x). CD133, x) CD44, xi) CD24 and xii) Aldehyde dehydrogenase. Study was done routine immunohistochemistry, double immunostaining and tissue micro array. Apropriate detection system was used. Results: There was 250 tumor tissue altogether majority with well differentiated morphology. All tumors showed variable range of positivity for the all the markers, lesser number of positive cells for CD24, CD44 and CD133. Even in double immunostaining, majority of the tumor cells showed co-expressions for the various immunomarkers. Different tumor samples from different patient population groups do not any significant differences. Mucosal dysplastic samples also showed similar pattern of positive staining as by the tumor cells. Ki67 posivity was variable, higher percentage of positivity in poorly differentiated tumor areas and related with the nucleostemin positive staining pattern. Conclusion: These observations indicate that these markers are non-specific and positivity does not specifically meant the presence of cancer stem cell. Possibly expression of these markers may indicate cell proliferative pathway markers.

Note: This abstract was not presented at the meeting.

Citation Format: Kim Vaiphei, Saroj Kant Sinha, Rakesh Kochhar. Identification of stem cell by immunohistochemistry in benign and malignant human esophageal mucosa. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1926. doi:10.1158/1538-7445.AM2014-1926
Abstract 1929: Tyrosine kinase inhibition with sorafenib but not pazopanib enriches for sarcoma cancer stem cells in diverse models of soft tissue sarcoma
Authors: Canter Robert J. , Ames Erik , Mac Stephanie , Grossenbacher Steve K. , Chen Mingyi , Tellez Joe , Monjazeb Arta M. , Murphy William J.
Published: May 2015

Purpose: Cancer stem cells (CSCs) are a putative source of resistance and relapse following conventional anti-proliferative therapies. We hypothesized that anti-proliferative, but not anti-angiogenic, tyrosine kinase inhibitors would enrich for CSCs in models of soft tissue sarcoma.

Experimental Design: We exposed multiple human sarcoma cell lines to sorafenib and pazopanib and assessed cell viability and expression of CSC markers. We exposed mice harboring lung/liver Ewing's sarcoma metastases to daily sorafenib and evaluated survival and CSC expression. We exposed dissociated primary sarcoma tumors to overnight sorafenib and pazopanib. We used tissue microarray (TMA) to evaluate the frequency and intensity of CSC markers in clinical sarcoma samples after neoadjuvant therapy with sorafenib.

Results: Viability following sorafenib exposure in vitro ranged from 1 - 20% with a corresponding 2 - 8.2 fold increase in ALDHbright cells from baseline (P<0.05), while negligible effects from pazopanib were observed. In vivo, sorafenib treatment improved median survival by 10 days (P<0.05), but increased the population of ALDHbright cells 2.5 - 2.8 fold (P<0.05). Analysis of primary human sarcoma samples revealed direct cytotoxicity following exposure to sorafenib with a corresponding increase in ALDHbright cells (P<0.05). Again, negligible effects from pazopanib were observed. TMA analysis of clinical sarcoma specimens demonstrated significant enrichment for ALDHbright cells in the post-treatment resection specimen following neoadjuvant therapy including sorafenib (P<0.05).

Conclusions: Sorafenib, but not pazopanib, exerts a direct anti-proliferative effect on sarcoma cells with a corresponding enrichment in sarcoma CSCs. Sustained anti-sarcoma therapeutic effects may require targeting of the CSC population in combination with cytotoxic treatments.

Note: This abstract was not presented at the meeting.

Citation Format: Robert J. Canter, Erik Ames, Stephanie Mac, Steve K. Grossenbacher, Mingyi Chen, Joe Tellez, Arta M. Monjazeb, William J. Murphy. Tyrosine kinase inhibition with sorafenib but not pazopanib enriches for sarcoma cancer stem cells in diverse models of soft tissue sarcoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1929. doi:10.1158/1538-7445.AM2014-1929
Abstract 1931: Tumor spheres growing from circulating tumor cells exhibit stem cell features
Authors: Pachmann Katharina , Pizon Monica , Zimon Dorothea
Published: May 2015

Background: Among the cells that are disseminated from a malignant tumor some are capable of resettling in distant organs and growing into life-threatening metastases. Therefore, the question arises how and whether such cells which have the potential to grow into metastases can be detected.

Materials and Methods: Using a nondissipative approach with only one enrichment step of red blood cell lysis, cells were cultured under conditions favoring the growth of epithelial cells. At 7, 14 and 21days the cell cultures were inspected for the appearance of spheroids staining with anti-EpCAM, anti-CD24 and anti-CD44 antibody and.expressing ALDH1.

Results: Tumorspheres from peripherally circulating cells from patients with malignant tumors in different stages of disease could so far be grown from 79% of 100 patients in whom more than 1000 epithelial tumor suspect cells per ml were detected. Numbers of tumorspheres correlated with the aggressiveness of the tumor and were highest in patients after surgery who had not yet received any systemic therapy. The size of the spheres increased from day 7 to day 21. They were negative for CD24 and positive for CD44. They highly express ALDH1 and thus exhibite typical features of stem cells.

Conclusion: Here, we demonstrate that the circulating tumor cells, detected in our approach contain a subpopulation with stem cell-like properties capable of growing into tumorspheres.

The frequency in peripheral blood of cells capable of forming tumor spheres seems to be dependent on the aggressiveness of the primary tumor.

Citation Format: Katharina Pachmann, Monica Pizon, Dorothea Zimon. Tumor spheres growing from circulating tumor cells exhibit stem cell features. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1931. doi:10.1158/1538-7445.AM2014-1931