bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 3430: Role of Tip60 in human melanoma cell migration, melanoma metastasis and patient survival
Authors: Chen Guangdi , Cheng Yabin , Zhang Zhizhong , Martinka Magdalena , Li Gang
Published: August 2012

The tumor suppressor Tip60 plays a major role in transcription, DNA damage response, apoptosis and cancer development, but its role in melanoma is unknown. In this study, we investigated the role of Tip60 in melanoma pathogenesis and assessed its prognostic value. Using tissue microarrays consisting of 448 cases of melanomas (201 for the training set and 247 for the validation set) and 105 cases of nevi, we found that Tip60 expression was significantly reduced in metastatic melanoma compared to normal nevi (P = 0.045), dysplastic nevi (P = 0.047) and primary melanoma (P = 0.001). Kaplan-Meier survival curve and univariate Cox regression analyses showed that reduced Tip60 expression was associated with a poorer five-year disease-specific survival in primary melanoma (P = 0.016) and metastatic melanoma patients (P = 0.027). Multivariate Cox regression analyses indicated that Tip60 expression was an independent prognostic marker for primary (P = 0.002) and metastatic melanomas (P = 0.035). In vitro wound healing assay showed that enforced Tip60 expression inhibited melanoma cell migration suggesting that Tip60 might regulate melanoma metastasis. Finally, we showed that overexpression of Tip60 in melanoma cells resulted in significantly increased chemosensitivity. Our data indicate that Tip60 may serve as a potential biomarker for melanoma patient outcome as well as a potential therapeutic target.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3430. doi:1538-7445.AM2012-3430
Abstract 3435: NM23-H1 suppresses melanoma cell motility by promoting strong adhesions between fibronectin and α4α1 integrin
Authors: Novak Marian , Yang Xiuwei H. , Jarrett Stuart G. , Kaetzel David M.
Published: August 2012

The metastasis suppressor NM23-H1 has a prominent role in melanoma and other leading malignancies, where loss of NM23-H1 expression is associated with onset of aggressive phenotypes and metastasis. NM23-H1 blocks multiple facets of the metastatic cascade, with autonomous cell motility being perhaps the most scrutinized across multiple cancer types. However, the molecular mechanisms through which NM23-H1 suppresses cellular motility in melanoma are poorly understood. Herein, we report a novel mechanism of motility suppression by NM23-H1 in melanoma via upregulation of the extracellular matrix (ECM) component fibronectin. In agreement with previous reports, forced expression of NM23-H1 in metastatic melanoma cell lines 1205LU and MDA-MB-435s/M14 led to a significant decrease in random cell motility. The resultant sedentary phenotype was associated with pronounced changes in cell morphology, including a highly flattened appearance and marked increases in actin stress fiber formation and the size of focal adhesions. In light of the known roles of cell adhesion in conveying such phenotypic changes, we measured the effect of NM23-H1 on expression and localization of fibronectin, a major component of focal adhesion complexes. Forced expression of NM23-H1 resulted in significantly increased expression of endogenous fibronectin protein, which was concentrated at focal adhesion sites. To assess the contribution of NM23-induced expression of fibronectin to formation of immobilizing adhesions, blocking antibodies directed against α4α1 and Δ5α1 integrins, the dominant fibronectin receptors on melanoma cells, were applied. Antibodies directed against integrin α4, but not Δ5, reversed the suppressing effect of forced NM23-H1 expression on cellular motility. These findings indicate a novel role of NM-23-H1 in regulating endogenous fibronectin-mediated cell movement, a critical aspect of melanoma metastasis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3435. doi:1538-7445.AM2012-3435
Abstract 3437: A natural plant product to inhibit breast cancer metastasis
Authors: Kundu Namita , Ma Xinrong , Goloubeva Olga , Holt Dawn , Kochel Tyler , Fulton Amy M.
Published: August 2012

In the United States, breast cancer death is the second leading cause of cancer deaths in women, primarily due to the occurrence of metastatic disease. We have identified a potential novel therapeutic agent derived from an edible root of the plant Colocasia esculenta, commonly known as taro, which has significant antimetastatic activity in a preclinical model of metastatic breast cancer and that should have minimal toxicity. We have shown for the first time that a water-soluble extract of taro (TE) potently inhibits lung colonizing ability (95-99%) as well as spontaneous metastasis from mammary gland-implanted tumors (85%), in a murine model of highly metastatic ER, PR and Her-2/neu negative breast cancer. TE modestly inhibits the proliferation of some, but not all, breast and prostate cancer cell lines and also causes morphologic changes including cell rounding. TE inhibits prostaglandin E2 (PGE2) levels and because PGE2 is a potent immune modulator, we examined the role of immunity in the therapeutic response to TE. We first examined the effect of TE on Natural Killer (NK) cell activities. TE modestly increases NK-mediated tumor cell lysis in vitro. We determined the effect of NK depletion on TE efficacy in vivo. The ability of TE to inhibit metastasis was modestly compromised in NK-depleted mice indicating that NK cells play a minor role in TE-mediated antimetastatic activity. To examine the role of T and B lymphocytes, TE efficacy was examined in Balb/c SCID mice. Antimetastatic activity of TE was completely lost in SCID mice lacking mature T and B cells. Thus, T and /or B cell functions contribute to the mechanism by which TE inhibits metastasis. In published studies we have identified the active component of TE as one of three closely related taro proteins, tarin, taro lectin and 12-kDa storage protein. Current studies are determining how these candidate proteins affect immune functions to inhibit breast cancer metastasis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3437. doi:1538-7445.AM2012-3437
Abstract 3442: Overexpression of Kruppel-like factor 4 inhibits the growth and migration in human hepatoma cells
Authors: Sung Ming-Ta , Lee Hsin-Chen , Chi Chin-Wen
Published: August 2012

The zinc-finger transcriptional factor Kruppel-like factor 4 (KLF4), can inhibit cell proliferation and maintain the differentiation of epithelial cells by regulating the expression of genes with GC-rich promoters, plays important roles in development and tumorigenesis. Recently, reduction of KLF4 expression has been reported in multiple gastrointestinal cancers such as gastric cancer, colorectal cancer and hepatocellular carcinoma (HCC), and this observation was associated well with tumor progression and poor clinical outcome. However, the exact role of KLF4 in the progression of HCC is still unclear. In this study, we used lentiviral transduction method to overexpress KLF4 in a highly metastatic HA22T/VGH hepatoma cell line. Using MTT and sulforhodamine B assay, we found that cell growth was decreased in KLF4-overexpressing HA22T/VGH cells as compared to parental cells. Moreover, wound healing assay revealed the migration ability was significantly suppressed in KLF4-overexpressing HA22T/VGH cells. Consistent with these findings, KLF4 overexpression also resulted in the up-regulation of E-cadherin expression and concomitant down-regulation of vimentin expression in HA22T/VGH cells. Moreover, our preliminary finding showed that KLF4 knockdown by transfection of KLF4 shRNA caused the decrease in E-cadherin expression in HEK293T cells. E-cadherin, a key adhesion molecule in the process of epithelial-mesenchymal transition (EMT) and tumor metastasis, was regulated by many transcription factors such as Snail. Interestingly, in this study we have found that KLF4 overexpression led to an obvious reduction in the Snail expression in HA22T/VGH cells. Therefore, these results together suggest that KLF4-induced E-cadherin expression may result from regulation at E-cadherin transcription level or inhibition of the expression of Snail. Furthermore, our findings also suggested that the role of KLF4 may be associated with the cell growth, EMT process and metastasis in the tumor progression of HCC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3442. doi:1538-7445.AM2012-3442
Abstract 3444: Exon 4 of osteopontin: A unique target to reduce malignant behavior in non-small cell lung cancer
Authors: Donington Jessica S. , Goparaju Chandra M. , Slomiany Mark , Hirsch Nathalie , Pass Harvey I.
Published: August 2012

INTRODUCTION: Osteopontin (OPN) is a ubiquitous protein associated with a wide range of normal and pathologic functions. It is a central regulator of malignant phenotype in non-small cell lung cancer (NSCLC). OPNa, the full length isoform, is disproportionately expressed in NSCLC tumors and cell lines, and increases malignant behavior when over expressed. OPNc, the shortest isoform, does not induce malignant properties when expressed in NSCLC. The only structural difference between OPNa and OPNc is the transcription of exon 4. The hypothesis of this project is that a small interfering peptide to OPN exon 4 will reduce in vitro malignant activity in NSCLC. METHODS: A 16-amino acid peptide which mimics the central sequence in OPN exon 4 and a scrambled sham were constructed and florescent labeled. Three NSCLC cell lines, H358 (low), A549 (moderate), and H460 (high endogenous OPN) were used in binding, proliferation, and invasion assays in presence of exon 4 mimic or sham. Cisplatin sensitivity was performed with peptides in A549. RESULTS: There was florescent evidence for cell surface binding of the exon 4 mimic in all of the NSCLC cell lines without binding of the sham. The exon 4 mimic significantly decreased in vitro invasion and proliferation in the A549 and H460 cell lines, with a lesser effect in H358 with low endogenous OPN. (Table) The exon 4 mimic increased cisplatin sensitivity, decreasing cell viability 2-fold compared to sham and control at cisplatin concentrations 0.1-0.8 uM/ml. CONCLUSIONS: Exon 4 of OPN has not previously been identified as a regulatory region essential for OPN's effect on malignant behavior. We have evidence for an un-described cell surface receptor to this region. A small mimicking peptide to OPN exon 4 significantly decreased in vitro malignant behavior, suggesting interference with important regulatory pathways. This novel binding site could serve as an ideal for target for antibody or small molecule therapies in NSCLC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3444. doi:1538-7445.AM2012-3444
Abstract 3445: Targeting Thromboxane A2 receptor (TP) to block breast cancer metastasis
Authors: Zhang Xuejing , Nie Daotai
Published: August 2012

The thromboxane A2 (TXA2) receptor, TP, is a G-protein coupled receptor. Previous studies in our lab have shown that the TP pathway regulates tumor cell cytoskeleton and TP activation induces rapid tumor cell contractions through small GTPase RhoA activation. Conversely, TP depletion reduces the metastatic dissemination of breast cancer cells in vivo by blocking the extravasation of tumor cells. Humans express two TP isoforms, TPγ and TPα. We report here that elevated TPγ expression is associated with metastasis in patients with breast cancer. While TPγ is expressed in all breast cancer cell lines that we examined, TPγ is only expressed in malignant cell lines, indicates that TPγ plays a role in breast cancer progression. Treatment with a selective TPγ inhibitor (CAY10535) blocks TP agonist (U46619) induced cell body contraction and RhoA activation. Additionally, TPγ inhibitor reduces migratory capacity and invasiveness in human breast cancer cell lines. Our previous work has shown that active TP is required for efficient extravasation of tumor cells in vivo; in this study, we further demonstrate that mice treated with SQ29548 (a high affinity TP antagonist) prior to tumor cell injection developed fewer metastatic lesions than the mice treated with SQ29548 after tumor cell injection. In all, our study indicated that TPγ can be targeted to reduce the risk of breast cancer metastasis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3445. doi:1538-7445.AM2012-3445
Abstract 3446: Stat3 is a potential molecular target for chemoradiosensitization of colorectal cancer cells
Authors: Spitzner Melanie , Roesler Birte , Bielfeld Christian , Gaedcke Jochen , Rave-Fränk Margret , Beißbarth Tim , Ried Thomas , Ghadimi B. Michael , Grade Marian
Published: August 2012

Introductory sentence: Resistance to preoperative chemoradiotherapy represents a major clinical problem in the treatment of patients with locally advanced rectal cancer. Therefore, the identification of novel molecular targets that are differently expressed in responsive and resistant tumors is exceedingly important. Furthermore, modulating target gene expression may sensitize a priori resistant tumors to multimodal therapy. Experimental procedures: Previously, we established an in vitro model for chemoradiotherapy in 12 colorectal cancer cell lines, and correlated differences in treatment sensitivity with pretherapeutic gene expression profiles. Within our signature we identified the signal transducer and activator of transcription 3 (STAT3), which was significantly correlated with treatment resistance. To test the functional relevance of the observed over-expression of STAT3, we first determined STAT3 mRNA and protein expression levels in all 12 cell lines. Subsequently, we established doxycycline-inducible stable shRNA single cell populations and a non-silencing shRNA (shNEG) in SW480. The induced single cell clones and shNEG were treated with 3µM 5-FU and exposed to 1, 2, 4, 6, and 8 Gy of X-rays. In addition, STAT3 was inhibited using two different siRNAs and a small-molecular inhibitor (STATTIC). Successful RNAi-mediated silencing of STAT3 and inhibitor treatment was detected by Western blot. Data: STAT3 was significantly overexpressed in resistant cells at mRNA and protein level. In stable STAT3 knockdown single cell clones and transiently siRNA transfected SW480 and SW837 cells, successful silencing of the STAT3 protein was detected after 72 hours, and STATTIC-induced inhibition of STAT3-phosphorylation after 1 hour. The silencing/inhibition resulted in a significantly increased chemoradiosensitivity with dose-reduction factors of 1.8 to 2. Conclusions: STAT3 is highly overexpressed in resistant colorectal cancer cells, and silencing of STAT3 leads to a significantly increased chemoradiosensitivity. This highlights the potential relevance of STAT3 as a novel molecular target in rectal cancer to sensitize a priori resistant colorectal tumor cells to chemoradiotherapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3446. doi:1538-7445.AM2012-3446
Abstract 3450: Functional characterization of a DNA damage response network in glioblastoma associated with long-term patient survival
Authors: Yoon Taewon , Loughlin Danielle , Yu Shuqian , Desai Brijal , Choe Kevin , Minn Andy J.
Published: August 2012

Glioblastoma multiforme (GBM) is the most aggressive primary brain cancer in humans with a median survival of less than 14 months. However, a small minority of GBM patients have a median survival of over three years. In an effort to identify genetic and epigenetic events that might explain this relative long-term survival, an integrative genomic approach was utilized. We show that in contrast to most GBM patients, relative long-term survivors have tumors that lack a biological network that responds to DNA damage. This network is comprised of pro-inflammatory genes and genes normally regulated through interferon signaling. By overlaying the network with phenotype information, key genes and gene-gene interactions that strongly associate with patient survival were identified to facilitate the discovery of important genes and genetic dependencies in the network. One such gene is Interferon-Stimulated Gene 15 (ISG15), which is part of the interferon subnetwork and encodes for an ubiquitin-like protein. Targeted disruption of ISG15 in various GBM cell lines unmasked a DNA damage response as characterized by delayed S-phase entry and G2/M accumulation, increased γH2AX, and senescence. Various genes that displayed a predicted interaction with ISG15 were tested for evidence for a biological interaction. Functional validation confirmed that these predicted interactions with ISG15 were mirrored by genetic and regulatory interactions that resulted in rescue of the effects of ISG15 knockdown. We also investigated genes that control the pro-inflammatory subnetwork. Targeted disruption of one such gene, MYD88, resulted in decreased invasion and increased sensitivity to DNA damage. In summary, we have identified a biological network that responds to and regulates DNA damage. The absence of network genes results in susceptibility to DNA damage, senescence, and decreased invasion. GBM patients with tumors lacking the network are rare long-term survivors of an otherwise uniformly and rapidly fatal tumor.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3450. doi:1538-7445.AM2012-3450
Abstract 3451: Lack of CD47 in the tumor microenvironment enhances anti-tumor adaptive immune responses when combined with ionizing radiation
Authors: Pantoja David R. Soto , Masaki Terabe , Ridnour Lisa A. , DeGraff William , Berzofsky Jay A. , Roberts David D.
Published: August 2012

Over half of the new cancer patients diagnosed this year in the United States will require ionizing radiation (IR) therapy as part of their course of treatment. Achieving a curative response, however, is limited by detrimental side effects and off-target toxicities of IR to normal cells. We previously demonstrated that CD47 null mice or blockade of CD47 confers radioprotection to normal tissues including radiosensitive hematopoietic progenitors. On the other hand, blockade of CD47 enhanced the radiation-induced tumor growth delay in two syngenic mouse models. One possible explanation for this observation is that, by protecting tumor-associated immune cells, CD47 suppression increases tumor immune surveillance. To examine the role of T cell immunity, we used the F15-12 RM mouse fibrosarcoma model in athymic mice. Blockade of CD47 in combination with IR did not alter tumor growth in these T-cell deficient mice versus IR alone. However, adoptive transfer of CD8+ T-cells in combination with CD47 blockade and IR significantly enhanced the reduction in tumor growth when compared to tumors of mice irradiated in combination with the T cell transfer alone (186 ± 50 vs. 370 ± 123 mm3 respectively, N=8). In vitro experiments showed that blockade of CD47 enhances antigen dependent CD8+ mediated cytotoxicity of tumor cells. Furthermore, in a syngeneic tumor model of B16 melanoma we observed over a 50% reduction in volume of irradiated tumors in a CD47-/- host versus a WT host. Immunohistochemical staining indicated an increase of intratumoral CD8+ cytotoxic T-cells. Further analysis indicated that lack or blockade of CD47 in combination with IR resulted in a significant increase in granzyme B expression, further indicating that the increased target cell death may be mediated by this pathway. CD47 suppression may also reduce tumor growth by altering the immunosuppressive factor VEGF. In both tumor models, either blockade of or lack of CD47 in combination with IR was associated with a reduction in VEGF. VEGF is a potent pro-angiogenic factor and a potent immunosuppressive factor that inhibits activation of cytotoxic T-cells. Our findings indicate that agents targeting CD47 enhance anti-tumor T cell immunity when combined with radiation. Combining CD47 suppression with IR and adoptive T cell transfer may increase the percentage of curative responses.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3451. doi:1538-7445.AM2012-3451
Abstract 3453: SPARC overexpression inhibits cell proliferation in neuroblastoma and is partly mediated by tumor suppressor protein PTEN and AKT
Authors: Bhoopathi Praveen , Gorantla Bharathi , Sailaja G.S. , Gondi Christopher S. , Gujrati Meena , Klopfenstein Jeffrey D. , Rao Jasti S.
Published: August 2012

Secreted protein acidic and rich in cysteine (SPARC) is also known as BM-40 or Osteonectin a multi-functional protein modulating cell-cell and cell-matrix interactions. In cancer, SPARC is not only linked with a highly aggressive phenotype, but it also acts as a tumor suppressor. In the present study, we sought to characterize the function of SPARC and its role in sensitizing neuroblastoma cells to radio-therapy. SPARC overexpression in neuroblastoma cells inhibited cell proliferation in vitro. Additionally, SPARC overexpression significantly suppressed the activity of AKT and this suppression was accompanied by an increase in the tumor suppressor protein PTEN both in vitro and in vivo. Restoration of neuroblastoma cell radio-sensitivity was achieved by overexpression of SPARC in neuroblastoma cells in vitro and in vivo. To confirm the role of the AKT in proliferation inhibited by SPARC overexpression, we transfected neuroblastoma cells with a plasmid vector carrying myr-AKT. AKT overexpression reversed SPARC-mediated PTEN and increased proliferation of neuroblastoma cells in vitro. PTEN overexpression in parallel with SPARC siRNA resulted in decreased AKT phosphorylation and proliferation in vitro. Taken together, these results establish SPARC as an effector of AKT-PTEN-mediated inhibition of proliferation in neuroblastoma in vitro and in vivo.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3453. doi:1538-7445.AM2012-3453
Abstract 3454: Establishing role of KRAS mutation on NSCLC radio-sensitivity
Authors: Bhardwaj Vikas , Likhacheva Anna , Byers Lauren A. Byers A. , Diao Lixia , Allen Pamela K. , Minna John D. , Ihle Nathan T. , Powis Garth , Das Amit K. , Girard Luc , Peyton Michael , Yordy John , Liao Zhongxing , Ang Kian K. , Story Michael , Kalhor Neda , Komaki Ritsuko , Kim Edward S. , Heymach John V. , Welsh James
Published: August 2012

Lung cancer is the leading cause of cancer related mortality in the US of which more than 75% cases are that of non-small cell lung carcinoma (NSCLC). Mutations in the proto-oncogene KRAS have been linked with poor prognosis for NSCLC patients. In this study, we aimed at analyzing the relationship between specific KRAS mutations and NSCLC cell radiosensitivity and protein expression patterns. We analyzed 22 NSCLC cell lines and stratified them according to their KRAS status. Our results show that NSCLC cells harbouring G12C mutations are more sensitive to radiation compared to cells with other KRAS status (SF2 = 0.35 ± 0.16 for G12C vs. 0.63 ± 0.17 for other KRAS mutants vs 0.54 ± 0.15 for wt KRAS). Our protein expression data suggests that G12C mutants have reduced expression of DNA-repair proteins such as ATM, Rad 50, Ku 80 and XRCC1 (p < 0.05) which may be responsible for their radiosensitive nature. Further we found that G12C mutant NSCLC cell lines have reduced expression of pAkt compared to cells with other KRAS status (p =0.009). This suggests that NSCLC cells harboring G12C mutation would be less susceptible to PI3K inhibition induced radio-sensitization. Our clonogenic assay results confirm our finding when 1-hour pretreatment with 5 µM LY294002 (PI3K inhibitor) sensitized H460 and A549 (non-G12C mutated NSCLC cells) but not H1792 and H23 (G12C mutant NSCLC). Our results strongly suggests that G12C KRAS mutant cells are radio-sensitive compared to NSCLC cells of other KRAS status and PI3K inhibitor therapy along with radiation could be beneficial for patients harboring non-G12C mutational KRAS status.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3454. doi:1538-7445.AM2012-3454
Abstract 3457: Galectin-1 suppression enhances combined anti-EGFR and radiation-therapy of NSCLC
Authors: Siedow Michael , Chakravarti Arnab , Lautenschlaeger Tim
Published: August 2012

Lung cancer remains the leading cause of cancer related death worldwide and will account for nearly 160,000 deaths in the United States alone in 2010. Between 80-90% of all cases diagnosed are classified as non-small cell lung cancer (NSCLC). Recent studies have shown a significant subpopulation of patients diagnosed with NSCLC have an activation of the epidermal growth factor receptor (EGFR) domain resulting from gene amplification, overexpression, or kinse-domain activating mutations. EGFR inhibitors such as Erlotinib and Gefitnib have shown promising results in this subpopulation of patients however median overall survival remains poor. LSGAL1, Galectin-1 (GAL1), is a beta-galactoside-binding protein we recently identified to play an important role in the activation of the PI3-Kinase pathway located directly downstream of EGFR. Silencing Galectin-1 in combination with an EGFR-inhibitor and radiation therapy may be a promising therapeutic strategy for patients with NSCLC. Using a short-hairpin RNA strategy we silenced GAL1 expression in four different NCSLC cell lines and assessed their relative radioresistance via clonogenic survival assay in the presence and absence of an EGFR inhibitor. In order to elucidate the mechanism between GAL1 and EGFR, western blotting and QPRC analysis was performed on downstream pathway members, specifically the RAS/PI3-Kinase and RAS/ERK signaling cascades. Functional assays focusing on proliferation/survival were carried out to determine the effect silencing GAL1 had on the combination of EGFR inhibition and radiation therapy in our NSCLC cell lines. Our preliminary results suggest silencing GAL1 reduces the clonogenic survival of NSCLC cells when used in combination with an EGFR inhibitor following irradiation. In addition well known players within PI3-Kinase pathway such as pAKT S473 appear to be altered in the absence of GAL1. Our preliminary findings suggest GAL1 is a promising therapeutic target in NSCLC when used in combination with an EGFR inhibitor and radiation therapy and is worthy of further investigation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3457. doi:1538-7445.AM2012-3457
Abstract 346: Functional role for axonal guidance molecule Sema7A in breast cancer metastasis: Epithelial to mesenchymal transition and tumor metastasis
Authors: Garcia-Areas Ramon , Libreros Stephania , Onwuha-Ekpete Lillian , Schilling Kathy , Iragavarapu-Charyulu Vijaya
Published: August 2012

Reactivation of embryogenesis related processes such as neurogenesis is a powerful mechanism used by tumor cells to enhance their survival and propagation. Recent studies have shown that many types of solid tumors express neurogenic molecules independent of the tumor's geography. Semaphorins are a compelling example of these pleiotropic neuronal molecules. Semaphorins were originally characterized for their role in axonal guidance and several of them have been found to play a role in cancer and other inflammatory diseases. Of the Semaphorins, Semaphorin7A (Sema7A) has not yet been studied in the context of cancer. It has however been associated with fibrosis, inflammation and immune modulation. Most semaphorins are repellent cues and inhibit cellular migration, but Sema7A is the only vertebrate semaphorin that serves as an axon chemoattractant. Sema7A also promotes dendricity, adhesion and motility during neuronal development, monocyte differentiation and osteoclast development. All these cellular properties have been attributed to Sema7A's ability to activate p38 mitogen-activated protein kinase pathway (MAP-kinase) through α1β1 integrins. We have recently discovered that Sema7A is over-expressed in the tumor tissue of breast cancer patients compared to the adjacent normal tissue. Within the tumor tissue, the mesenchymal cancer stem cells had the highest expression of Sema7A. We have also found that breast cancer cell lines of a mesenchymal phenotype express high levels of Sema7A and that transforming growth factor beta-1 can induce Sema7A expression in breast epithelial cells. Further, we show that mice bearing Sema7A gene silenced mammary tumors had decreased tumor growth and metastasis with enhanced survival compared to the control tumors. Our studies aim to unravel the functional role of Sema7A in breast cancer progression. We hypothesize that Sema7A expression in tumor cells may lead to increased tumor cell dendricity, migration, and adhesion through the activation of the MAP-kinase pathway and mediating epithelial to mesenchymal transition (EMT). Similar to its role in neurogenesis, in the tumor microenvironment Sema7A could contribute to tumor cell migration and tissue remodeling. Therefore, Sema7A could prove to be a novel therapeutic target to limit tumor growth and metastasis not only for breast cancer but for other solid tumors as well.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 346. doi:1538-7445.AM2012-346
Abstract 3460: Inhibition of c-met radio-sensitizes in breast cancer brain metastatic cancer
Authors: Yang Heekyoung , Jin Juyoun , Kim Misuk , Kim Kang Ho , Kim Donggeon , Kang Wonyoung , Lee Hyewon , Joo Kyeung Min , Nam Do-Hyun
Published: August 2012

Ionizing radiation (IR) is a critical component in the treatments of breast cancer patients with all stages of the disease and a gold standard modality in patients with multiple brain metastasis, demonstrating improved overall survival (OS) in recent meta-analysis. However, the problem of recurrent or persistent disease exists due to tumor radio-resistance, and the development of distant metastasis after IR has presented a major obstacle to treatment. We investigated which molecule could be targeted for radio-sensitization. We found that c-Met over-expression and activation of downstream-signaling were induced in response to IR in a panel of human breast cancer cells by q-PCR, FACS, and Western blot analysis. The radio-sensitizing effect of c-Met silencing in vitro showed that increased c-Met activity is required for radio-resistance. In addition, c-Met inhibition combined with IR showed synergistic antitumor response including improved tumor regression and lengthened overall survival in breast cancer orthotopic and experimental brain metastasis xenograft models. Our preclinical findings establish a basis for a novel strategy to target the HGF/c-Met pathway with radiation when treating primary and brain metastatic breast cancer and possibly other c-Met pathway dependent cancers.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3460. doi:1538-7445.AM2012-3460
Abstract 3464: Aminolevulinic acid-mediated photodynamic therapy induces cell death in human osteosarcoma cells
Authors: Newton Mariko , White Bradley , Rossi Vincent , Baugher Paige J.
Published: August 2012

Photodynamic therapy (PDT) is a localized cancer treatment that requires a photosensitizer (PS), molecular oxygen, and light to induce cell death. Aminolevulinic acid (ALA)-mediated PDT utilizes ALA as an inert precursor to the required PS. Subsequent to cellular uptake ALA is converted to a PS, protoporphyrin IX (PpIX), in the mitochondria via the heme pathway. The excitation of PpIX by light can then result in the generation of reactive oxygen species, leading to direct tumor cell death, damage to the microvasculature, and induction of local inflammatory response. Interestingly, PDT can evoke apoptotic and/or necrotic cell death pathways within the same cell population. The balance between apoptosis and necrosis depends on several parameters, including the total PDT dose, the intracellular localization of the PS, the fluence rate, and the cell type. Recent studies show that the cell death mechanism induced has a direct influence on the systemic immune response. Therefore, a better understanding of the interplay between different cell death mechanisms in response to PDT could lead to improved tumor response and could inform better therapeutic strategies. We first determined the cytotoxicity of ALA to the human osteosarcoma cell line MG-63. PDT is a relatively unexplored method of treatment for human osteosarcoma, and could represent a superior method to existing therapies. Data from our lab show that ALA is not significantly cytotoxic to MG-63 cells, and that it is efficiently converted to PpIX within 24 hours of treatment. We also demonstrate that ALA-mediated PDT significantly induces cell death in MG-63 cells, and that cell death increases with increased ALA concentration and light fluence. Our findings indicate that this cell death results from a combination of both apoptosis and necrosis, with necrosis representing the major pathway. Finally, we show that increased light fluence decreases the amount of observed apoptosis subsequent to ALA-mediated PDT. These results taken together suggest that ALA-mediated PDT can induce cell death in human osteosarcoma cells, and that most cells are dying by necrosis. Furthermore, our data suggests that by adjusting specific therapeutic parameters, we can shift the balance between separate death pathways.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3464. doi:1538-7445.AM2012-3464
Abstract 3466: Mitochondrial targeting photosensitizer-lipophilic cation conjugates for photodynamic therapy
Authors: Rajaputra Pallavi , Nkepang Gregory , You Youngjae
Published: August 2012

Mitochondrion of a living cell plays a pivotal role in apoptosis. Targeting the mitochondria of cancer cell for the induction of apoptosis in photodynamic therapy (PDT) has gained importance. Cancer cells have higher plasma and mitochondrial membrane potential compared to normal cells, consequently delocalized lipophilic cations (DLCs) tend to accumulate more in them than in normal cells. In PDT photosensitizers can be specifically delivered to the mitochondria of cancerous cell by conjugating them with DLCs. Three conjugates: CMP-TPP (a porphyrin-triphenyl phosphene monocation conjugate) and CMP-(TPP)2 (a porphyrin- triphenyl phosphene dication conjugate), CMP-Rh (a porphyrin -rhodamine monocation conjugate) were synthesized as mitochondria targeting photosensitizers. The conjugates were synthesized by conjugating a core modified porphyrin (CMP-TPP) to either 1 or 2 triphenyl phosphene (TPP) molecules or rhodamine B (Rh B) respectively via a saturated hydrocarbon linker. To evaluate the efficiency of the conjugates, the photophysical properties like fluorescence resonance energy transfer (FRET in CMP-Rh) and singlet oxygen generation was compared to that of the unconjugated CMP. Potent in vitro photodynamic activity was observed in Colon 26 cells upon treatment with CMP conjugates and exposure to 690 nm diode laser light source (5.6 mW/cm2 for 30 min, 10.8 J/cm2). No significant darktotoxicity was observed in cells treated up to 5 μM of the conjugates. The conjugates showed approximately 12-14 times higher uptake in Colon 26 cells compared to unconjugated porphyrin. Further, sub-cellular localization, comparison of preferential uptake by cancerous cells versus normal cells, in vivo bio-distribution, PDT in BALB/c mice will be discussed.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3466. doi:1538-7445.AM2012-3466
Abstract 3468: Endoscopic diagnosis and treatment of esophageal tumor using a novel DDS-type photoactivatable agent
Authors: Miyazaki Kozo , Morimoto Yuji , Hiruma Hitomi , Inoue Aki , Nomoto Takahiro , Fukushima Shigeto , Iwaya Keiichi , Shinomiya Nariyoshi , Nishiyama Nobuhiro , Kataoka Kazunori
Published: August 2012

Introduction: Photodynamic diagnosis (PDD) and therapy (PDT) have been clinically used for the early phase cancer of hollow organs. We are advancing the photomedicine to the next stage, in which treatment is carried out immediately after the detection of lesions. For achieving the simultaneous diagnosis and treatment, we established a novel DDS-type photoactivatable agent, micelle-based photosensitizer loading dendrimer porphyrin (DP/M). A micelle-based shell structure is expected to be selectively accumulated in tumors. An intensely emitted fluorescence from porphyrin can be used for lesion detection and a highly quantum yield of porphyrin promises an effective PDT. Apart from the agent, we recently developed a fluorometric system equipped with an ultrathin endoscope that has a spatial resolution of 15,000 pixels even with a diameter of 0.8 mm. The aim of this study was to verify practical effectiveness of the novel photosensitizer combined with the endoscopic fluorometric system for simultaneous diagnosis and treatment. In this study, we targeted esophageal cancer because satisfactory results are not always obtained with conventional therapies and an endoscopic approach is applicable. Materials and Methods: A rat orthotopic esophageal tumor model was established in female Fischer F344 rats by orally administered with NMBuA (N-Nitroso Methylbutylamine) solved in drinking water. After intravenous administration of DP/M, PDD was carried out using the endoscopic fluorometric system (ex. 405 nm, em. > 630 nm). After the detection of lesions, tumors were irradiated using a diffuser tip fiber connected to a 635nm LD laser. Results: About 6 weeks after the administration of NMBuA, polypoid tumors were observed in the esophagus. Pathological analysis revealed that proliferated polymorphonuclear cells were seen: a part of which reached the muscular layer of mucosa. A selective accumulation of DP/M in the tumors was confirmed with the endoscopic fluorometric system. This modality enabled repeated observations of tumors without sacrifice. The following PDT provided a promising result. Conclusions: DP/M combined with the endoscopic fluorometric system brought the simultaneous diagnosis and treatment for the orthotopic rat esophagus tumor models. Acknowledgment: This research is granted by the Japan Society for the Promotion of Science (JSPS) through the “Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST Program),” initiated by the Council for Science and Technology Policy (CSTP).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3468. doi:1538-7445.AM2012-3468
Abstract 3471: Paclitaxel selects and enriches for CD44+/MyD88+ ovarian cancer stem cells
Authors: Alvero Ayesha B. , Craveiro Vinicius , Holmberg Jennie , Yang Yang , Mor Gil
Published: August 2012

Background: Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy. The current standard of care in the treatment of EOC patients is surgical debulking and combination chemotherapy usually with Carboplatin and Paclitaxel. Although effective in majority of the cases, more than 20% of patients do not respond. Moreover, more than 80% of patients present with recurrent disease within 5 years. Therefore, there is an underlying biology that results in the differential response to treatment as well as the occurrence of recurrent disease. Tumors are heterogeneous and consist of multiple types of cancer cells, which exhibit different chemoresponsiveness. Our group previously described the characterization of CD44+/MyD88+ EOC stem cells and demonstrated their tumor-initiating properties. An important characteristic of these cells, which differentiate them from the CD44-/MyD88- EOC cells, is the presence of a functional TLR4-MyD88-NFkB pathway. This pathway confers Paclitaxel resistance to these cells. We hypothesize that a cause for recurrence following Paclitaxel treatment is the selective survival of cancer stem cells capable to recreate the tumor. In this study, we demonstrate that Paclitaxel enriches for the CD44+/MyD88+ EOC stem cells thus promoting recurrence. Methods: In vitro model: co-culture system consisting of (50%:50%) GFP+ CD44+/MyD88+ and RFP+ CD44-/MyD88- cells treated with 0.2 uM Paclitaxel. In vivo model: Ovarian tumors implanted s.c in Nude mice treated with 10 mg/kg Paclitaxel q3d for 21 days. Levels of GFP+ and CD44+ cells were determined by flow cytometry. Klf-4, Nanog, MyD88, and ALDH1 were determined by qPCR or western blot. Results: Control co-cultures were characterized by overgrowth of CD44-/MyD88- EOC cells while the Paclitaxel treated co-cultures had mainly CD44+/MyD88+ EOC stem cells. Similarly in vivo results show enrichment in CD44+ cells with Paclitaxel (49% CD44+ in control vs 88% CD44+ with treatment). Analysis of genes associated with stemness showed upregulation of Klf-4, Nanog ALDH1, and MyD88 in the cultures treated with Paclitaxel compared to control. Conclusion: We demonstrate that Paclitaxel selectively induce cell death in CD44-/MyD88- EOC cells but has a pro-survival effect and enhances self-renewal in the pleuripotent and chemoresistant CD44+/MyD88+ EOC stem cells. Based on these data, we propose that the mode of management for EOC patients should take into consideration the tumor's molecular phenotype. Our results highlight the need to identify patients that should not receive Paclitaxel - not only because they are resistant, but more importantly, because it can enrich for the more aggressive cancer stem cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3471. doi:1538-7445.AM2012-3471
Abstract 3476: Hyaluronan-mediated motility receptor as a novel target for inhibiting glioblastoma stem cells
Authors: Ying Mingyao , Tilghman Jessica , Laterra John
Published: August 2012

Introduction: Glioblastoma stem cells (GSCs) are a subpopulation of tumor cells that promote tumor invasion and angiogenesis, therapeutic resistance and tumor recurrence. Here, we study the function of hyaluronan-mediated motility receptor (HMMR) in human GSCs. HMMR is hyper-expressed in human glioblastoma samples relative to lower-grade glioma and non-neoplastic specimens. Hyper-expression of HMMR also correlates with poor survival in glioma patients. HMMR is a multifunctional oncogenic protein that plays essential roles in tumorgenesis. Extracellular HMMR forms a complex with CD44 that upon binding to hyaluronan activates intracellular signaling pathways that regulate tumor cell survival, proliferation and invasion. Intracellular HMMR associates with microtubules, interacts with the mitotic spindle and contributes to tumor progression by promoting genomic instability. HMMR and CD44 are two ubiquitous receptors for hyaluronan, which is a prominent component of the microenvironment in most malignant tumors. CD44 has been identified as a cancer stem cell marker and CD44 directly regulates cancer stem cells in a variety of cancers including glioblastoma. Critical evidence regarding the function of HMMR in actual glioblastoma tumors and in the context of tumor-initiating GSCs is still lacking. Results: We found that HMMR is ubiquitously expressed in a panel of human glioblastoma-derived neurosphere cultures that are enriched for GSCs. Targeting HMMR by lentivirus-mediated shRNA delivery potently disrupted in vitro self-renewal of GSCs and inhibited the expression of key GSC markers, such as CD133, SOX2 and Olig2. HMMR knockdown also blocked the in vivo tumorigenic potential of GSCs in mouse orthotopic xenograft model. Notably, disruption of HMMR in GSCs attenuated the activity of Notch signaling, which supports the cancer stem cell hierarchy in glioblastoma and various other cancer types. Significance: This research identifies HMMR as a novel therapeutic target in the treatment of glioblastoma by depleting the tumor-initiating GSCs. It also introduces a novel hypothesis regarding the mechanistic crosstalk between HMMR-mediated signaling and Notch signaling pathway. Understanding this crosstalk between HMMR and Notch signaling will have a significant impact on current efforts to target Notch driven mechanisms for GBM therapy. Overall, these studies will lay an essential foundation for the development of HMMR-targeting strategies, such as HMMR inhibitors or monoclonal antibodies, as new therapeutic approaches targeting glioblastoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3476. doi:1538-7445.AM2012-3476