bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 554: The impact of matrigel on the evaluation of nanomedicines in a mouse model of human breast adenocarcinoma
Authors: Shuhendler Adam J. , Prasad Preethy , Hui Kelvin KW , Rauth Andrew M. , Henderson Jeffrey T. , Wu Xiao Yu
Published: June 2012

There exists a disparity in the literature on the use of matrigel, a mouse tumor derived basement protein scaffold solution, in the establishment of orthotopic mouse models of human breast cancer. Whether or not a tumor model requires matrigel is rarely, if ever, discussed, and whether or not matrigel has any confounding effects on the assessment of nanomedicines in these models has not been determined. To this end, the effects of matrigel on the assessment of a potential nanoparticle carrier in an orthotopic model of human breast cancer was evaluated. Bilateral human enhanced green fluorescent protein-expressing MDA435 breast tumors were established in the inguinal mammary fat pads of Nude mice with (left side, M+) or without (right side M-) co-injection of Matrigel. To determine if M- or M+ breast tumors resulted in altered retention of near-infrared emitting solid lipid nanoparticles (SLN), SLN were injected intratumorally and the tumor-retained near-infrared fluorescence was tracked over time. Lymphatic flow was tracked in a caudal-to-rostral direction through the subcutaneous injection of indocyanine green into the tail interstitium lateral to the ventral caudal artery. Tumor and lymph node morphologies were assessed with high frequency ultrasound imaging, and local perfusion of these structures was measured with destruction-replenishment of microbubbles. There was a significant difference in the retention time of SLN within M+ and M- tumors, with the retention of SLN in M- tumors beyond 6 hours but near total SLN clearance from M+ tumors within 2 hours of administration. Anatomical interrogation of the M+ and M- tumor growth with fluorescence imaging revealed occlusion and overgrowth of the inguinal lymph nodes by M+ tumors, whereas M- tumors neither occluded nor overgrew the lymph node, but rather grew in its periphery. Corroboration of these findings was achieved using ultrasound imaging, demonstrating the reduction of lymph node area by the overgrowing M+ tumors that was not seen with M- tumors. M+ and M- tumors also differed physiologically both in lymphatic flow rates and lymph node blood perfusion rates, where the M+ associated lymphatics showed significantly greater lymphatic flow and lymph node perfusion relative to the M- associated lymphatics. The alteration of both anatomical and physiological parameters of lymphatic flow and lymph node perfusion by M+ orthotopic breast tumors relative to M- tumors and the effect of these alterations on the performance (i.e. retention) of nanomedicines warrant scrutiny of the use of matrigel in the establishment of tumor models for nanomedicine evaluation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 554. doi:10.1158/1538-7445.AM2011-554
Abstract 5540: CCN5/WISP-2 prevents leptin-induced breast cancer cell growth and migration
Authors: Haque Inamul , Banerjee Snigdha , Dhar Kakali , Chattopadhyay Indranil , Ray Amitabha , Banerjee Sushanta K
Published: June 2012

In menopausal women, one of the important risk factors for breast cancer is obesity/adiposity. Despite multiple studies, the biological mechanism by which obesity influences the breast carcinogenic process is still unclear. It is evident from various studies that leptin, a 16 kDa protein hormone over produced in obese people, plays a critical role in neovascularization and tumorigenesis in breast and other organs. Present studies demonstrate that leptin is able to induce proliferation and migration of estrogen receptor positive MCF-7 and ZR-75-1 breast tumor cell lines in a dose-dependent fashion but these effects are minimal in ER-negative MDA-MB-231 cells. Additionally, these studies found that leptin suppresses the transcriptional activation of anti-invasive gene CCN5/WISP-2. Although the suppression of CCN5 has no impact on the constitutive proliferation of these cells, it is critical for leptin-induced proliferation and necessary for the induction of in vitro migration of these cells because the addition of CCN5 recombinant protein into the media markedly inhibits the leptin-induced proliferation and migration. Collectively, these in vitro studies suggest that CCN5 may serve as a gatekeeper for leptin dependent breast carcinogenesis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5540. doi:10.1158/1538-7445.AM2011-5540
Abstract 556: Extracellular sulfatase 2; enzymatic inhibition by OKN-007 a disulfonylphenyl nitrone with anticancer activity and other sulfamate and sulfone compounds
Authors: Floyd Robert A. , Chandru Hema K. , Towner Rheal A.
Published: June 2012

Sulfatase 2 (Sulf2) is an extracellular enzyme which catalyzes the removal of 6-O-sulfate groups on glucosamine from subregions of the glycosaminoglycan heparin sulfate. Sulf2 action alters the binding of protein ligand growth factors such as VEGF, FGF-2, TGF and SDF-1 to heparin and cellular receptors. Sulf2 is enriched in several tumors including breast cancer, pancreatic cancer, lung cancer and liver cancer and studies in experimental models have shown its action is important in cancer development. We have shown that PBN (α-phenyl-tert-butylnitrone) nitrones have anti-cancer activity in experimental cancer models including the rat choline deficiency liver cancer model, the mouse APCmin model of colon cancer and the rat C6 glioma model. Studies of the PBN derivative 2,4-disulfonylphenyl-tert-butylnitrone in the C6 glioma model showed that it has more potent anti-cancer activity in this model than PBN. We considered that the sulfonyl groups on OKN-007 acting to inhibit the activity of Sulf2 could account for its anti-cancer activity and therefore set up experiments to test this concept. We have shown that OKN-007 does inhibit Sulf2 at biological meaningful concentrations. In addition we have partially completed an MCF-7 xenograph study that indicates OKN-007 administered orally does suppress cancer growth in this model. We have also shown that another compound suramin that has 6 sulfonyl groups and has been shown to have anti-cancer activity also suppressed the enzymatic activity of Sulf2. In addition we have also tested some compounds that have sulfamate and sulfone functional groups and have found that they also show some activity in suppressing the enzymatic action of Sulf2. Studies are continuing to elucidate the significance of the action of OKN-007 on Sulf2.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 556. doi:10.1158/1538-7445.AM2011-556
Abstract 5589: An aqueous extract of Allspice (berries of Pimenta dioica) inhibits breast cancer growth through autophagy by targeting the estrogen receptor
Authors: Zhang Lei , Shamaladevi Nagarajarao , Lokeshwar Bal L.
Published: June 2012

Background: Breast cancer (BrCa) ranks second as cause of cancer deaths in women. However, >90% of BrCa patients survive >5 years after diagnosis, thus providing an chance to prevent clinical progression and metastasis. Several chemopreventive agents are currently under investigation, however, no single agent is highly effective. Dietary agents offer an advantage for long-term, well tolerated and personalized treatment for chemoprevention. With this goal, we investigated anticancer effects of an aqueous extract of a common spice, the unripe berries of Pimenta dioica (Allspice).

Methods: An aqueous exact of Allspice was prepared, lyophilized and a solution of suitable strength was tested on several BrCa cell lines (MCF-7, MDA-MB231, SKBr3) for potential inhibition of clonogenic growth, autophagy and estrogen-receptor inactivation using commonly used analytical techniques. Potential effect on estrogen receptor (ERα) levels and transcriptional activities were determined using quantitative-real time PCR and western blotting.

Results: AAE reduced the viability and clonogenic growth of BrCa cells (IC50≈ 100μg/ml). Importantly, AAE was selectively effective against proliferating cells but not quiescent cells. In addition to cytotoxicity, AAE reduced ERα in an estrogen-dependent BrCa cell line, MCF-7. ERα protein levels were significantly decreased in AAE treated MCF7 cells (IC50≈ 100μg/ml). The decrease in ERα protein level by AAE was not rescued by MG132, a proteasome inhibitor, treatment indicating, it is likely due to AAE effect on ERα synthesis and not turnover. We did not detect AAE induced apoptosis in MCF-7 cells as confirmed by several assays. However AAE induced the expressions of autophagy-related proteins, microtubule-associated protein 1 light chain 3 (LC3).

Conclusion: We demonstrate anti-proliferative and anti-ERα activity of the aqueous extract of Allspice, a highly aromatic and delectable culinary additive world over. The cytotoxicity of this anticancer agent encompassed multiple pathways, including autophagy and ERα down modulation. These results, if found corroborative using studies in vivo models, should provide a strong rationale to test as an anti-cancer agent in breast cancer. [Grant Support: 1R01AT003544 (BLL)]

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5589. doi:10.1158/1538-7445.AM2011-5589
Abstract 567: Tumor suppressor merlin and WWOX involve in regulating tumor cell growth via epithelial mesenchymal transition (EMT)
Authors: Shen Wan-Jou , Huang Yu-Feng , Lin Han-Yu , Sze Chun-I , Chang Nan-Shan
Published: June 2012

Cancer radiotherapy may complicated by chemo/radiation-induced resistance. Gene expression profiling studies have revealed that the tumor carries mesenchymal signature is a poor prognostic predictor. Our laboratory had generated post-irradiated 1306-MG glioblastoma (GBM) cell line which expresses epithelial mesenchymal transition (EMT) markers such as vimentin, fibronectin, desmin, and carbonic anhydrase III. Nuclear translocation of vimentin also occurs in these cells. These findings all indicate EMT. EMT requires cells transition and detachment which is mainly driven by a hyperactive Raf/MAPK pathway via transforming growth factor β (TGF-β) signaling. TGF-β signaling interacts with cell surface Hyal-2 and recruits WWOX. We treated 1306-MG with hyaluronan (HA) and co-transfected with wild type, active form, and inactive form merlin plus WWOX. By fluorescence resonance energy transfer (FRET) and co-immuoprecipitation (CO-IP) assays, our data showed that WWOX interacted with merlin in GBM cell line after treated with hyaluronan (HA). This finding suggest that WWOX participates in the regulation of CD44/merlin signaling. The growth of 1306-MG in merln or WWOX transfected cells showed more cells in S/G2M phases than co-tranfected cells. The co-tranfected WWOX with wild type or active form merlin induced growth arrest in cell cycle were greater than single-tranfected merlin or WWOX. However, inactive form merlin and WWOX co-tranfection caused a growth permissive state was identified by flow cytometry analysis. Using soft agarose colony survival assay, we determined that colony number in co-transfected cells with WWOX plus wild type and active form merlin were more doubled than cells transfected with inactive form merlin plus WWOX. On the contrary, co-transfected cells with wild type and active form merlin plus WWOX, colony size was smaller than co-transfected with inactive form merlin plus WWOX. Given the presence of EMT marker proteins in post-irradiated GBM cell lines, we hypothesize that merlin interacts with WWOX may interfere TGF-β signal pathway and EMT. Analysis data from 1306-MG cells after 12 Gy irradiation and transfected WWOX plus individual types of merlin, we found EMT makers such as vimentin and fibronectin were also significantly increased, especially in cells co-transfected with WWOX and inactive form merlin. Data obtained from cells treated with TβRI/II inhibitor suggested that these changes were TGF-β-dependant. According to these results, we conclude that TGF-β signaling recruits merlin/WWOX and via its interaction to promote cell growth and EMT in post-irradiated GBM cell line in vitro.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 567. doi:10.1158/1538-7445.AM2011-567
Abstract 585: PTEN is a critical determinant in sensitizing cells to γ-secretase inhibitors
Authors: Nair Jayasree S. , Sheikh Tahir N. , Li Yueming , Schwartz Gary K.
Published: June 2012

Phase I studies of gamma secretase inhibitors (GSIs) that block Notch signaling have indicated clinical activity, especially in patients with sarcomas and melanoma. None of these patients had activating mutations, yet they showed intrinsic sensitivity to the drug. Therefore, an understanding of the mechanisms for de novo sensitivity and resistance to this class of drugs would be critical for drug development. Towards this end, we treated a panel of human melanoma and sarcoma cells lines with JC-34, a potent inhibitor of gamma secretase. Even though all the cell lines showed inhibition of cleaved Notch 1 and suppression of Hes1 luciferase, only some of the cell lines showed inhibition of growth or induction of apoptosis. The sensitive cell lines also underwent G1 cell cycle arrest. In addition, all the sensitive cell lines were characterized by induction of PTEN and suppression of p-AKT (473) after the administration of JC-34. Melanoma cell lines with wild type PTEN were sensitive (SKMEL 32 and SKMEL 267) while PTEN mutant/ null cells were insensitive (SKMEL 39 and 133). In order to further assess the impact of PTEN status upon drug susceptibility, we compared the impact of JC-34 upon isogenic breast cancer cell lines that differ only in PTEN status. In the breast cancer cell line MDAMB468, proliferation inhibition was approximately 50% in the presence of PTEN expression compared to 10% in MDAB468 cells without PTEN expression. In this system, induction of apoptosis was a significant contributor to inhibition of proliferation. Taken together, these data suggest that the status of PTEN before and/or after drug treatment may play a critical role in determining tumor susceptibility to Notch pathway inhibition. As PTEN is negatively regulated by Notch, modulation of PTEN status by GSIs may provide a rationale means to explain sensitivity of this class of drugs to particular subsets of tumor. This hypothesis will be validated in planned clinical trials with GSIs in patients with these diseases.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 585. doi:10.1158/1538-7445.AM2011-585
Abstract 625: Preclinical characterization of an auristatin-based anti-CD19 drug conjugate, SGN-19A
Authors: Law Che-Leung , Sutherland May , Miyamoto Jamie , Hayes Dawn , Duniho Steve , Boursalian Tamar , Stone Ivan , Jonas Mechthild , Smith Leia , Benjamin Dennis
Published: June 2012

CD19 has multiple attributes that make it an attractive target for an antibody-drug conjugate (ADC). CD19 is uniformly expressed on the cell surface of almost all malignancies of B cell origin, including non-Hodgkin lymphoma (NHL), B cell precursor acute lymphoblastic leukemia (B-ALL), and chronic lymphocytic leukemia (CLL). In addition, CD19 has very limited normal tissue expression, restricted only to B lymphocytes and their precursors, and it internalizes rapidly, which are favorable characteristic for targeted drug delivery. SGN-19A is an ADC comprised of a humanized anti-CD19 mAb and the potent cytotoxic drug-linker maleimidocaproyl monomethyl auristatin F (mcMMAF). Here we demonstrate internalization and trafficking, in vivo antitumor activity, and in vivo on-target pharmacodynamic effect of B cell depletion following SGN-19A treatment. Internalization and trafficking of SGN-19A through the endosomal-lysosomal pathway resulted in potent in vitro cytotoxic activity against CD19+ cell lines derived from B-ALL, follicular lymphoma, diffused large B cell lymphoma, Burkitt's lymphoma, and plasma cell leukemia. In mouse xenografts modeling different B-lineage malignancies, SGN-19A demonstrated antitumor activity including tumor regression and prolonged survival at doses well below its maximum tolerated dose. We also show that the in vivo antitumor activity is directly related to the duration of the pharmacokinetic half-life among a panel of ADCs targeting CD19. Since SGN-19A cross-reacts with its ortholog expressed in non-human primates, we examined its pharmacodynamic effect on B cell depletion in cynomolgus monkeys. Depletion of peripheral B cells was observed following SGN-19A and correlated with results from terminal immunohistochemical (IHC) analysis demonstrating the depletion of Ki67+ germinal center B cells. Furthermore, using an antibody against mcMMAF we confirmed delivery of the cytotoxic agent to the B cell areas in peripheral lymphoid tissues. Taken together, these results support the further evaluation of SGN-19A as a therapy for B-lineage derived malignancies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 625. doi:10.1158/1538-7445.AM2011-625
Abstract 642: Novel EGFR inhibitory antibodies directed against EGFR mutants with potentially reduced toxicity
Authors: Wang Fang , McIntosh Donna , Bottega Steve , Zhou Yinghui , Fleet Christina , Jiang Jinwei , Chen Tin , Weiler Solly , Winston William , Heyer Joerg , Clark Steven , Gyuris Jeno , Vincent Sylvie
Published: June 2012

Non-small cell lung cancers (NSCLC) driven by ligand-independent activating mutations in epidermal growth factor receptor (EGFR) often respond to treatment with EGFR tyrosine kinase inhibitors (TKIs). About half of acquired resistance to EGFR-TKI therapy results from a secondary point mutation in the EGFR tyrosine kinase domain at amino acid position 790 (T790M). T790M mutants also display reduced sensitivity to Cetuximab treatment. We have investigated the molecular mechanism responsible for the reduced Cetuximab sensitivity and found that T790M mutant receptors primarily exist and signal as monomers. We have exploited this characteristic of the T790M mutant to isolate novel EGFR inhibitory antibodies with activities against all EGFR variants.

In addition, as opposed to other EGFR inhibitory antibodies, these novel antibodies have reduced ligand binding inhibitory activity and minimal inhibitory effect on EGF induced human primary keratinocyte proliferation, suggesting a potentially reduced skin toxicity profile. The broad activity profile, combined with potentially reduced skin toxicity, suggests that these antibodies will have great potential for combinability with other therapeutic agents.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 642. doi:10.1158/1538-7445.AM2011-642
Abstract 647: TTAC-0001, anti-VEGFR2/KDR monoclonal antibody, inhibits VEGFR signaling and tumor growth in preclinical models
Authors: Jin Younggeon , Jin Juyoun , Yang Heekyoung , Park Minjae , Lee Weon Sup , Kim Sung-Woo , Shim Sang Ryeol , Kim Yeonjoo , Lee Sang Hoon , Yoo Jin-San , Seol Ho Jun , Nam Do-Hyun
Published: June 2012

Tumor angiogenesis is the process that leads to the formation of blood vessels in a tumor and a prognostic indicator in various cancers. Vascular endothelial growth factor (VEGF) and its receptors are considered to be primary regulators of tumor-induced angiogenesis and activation of VEGFR2/KDR is the major signaling pathway for tumor growth. In addition, VEGFR2/KDR is also expressed in many cancer cells, and regulates cell growth and survival through autocrine pathway. In this study, we evaluated the therapeutic potential of TTAC-0001, fully human antibody against VEGFR2/KDR, for the inhibition of tumor growth. In the tube formation assay using HUVEC, TTAC-0001 exhibited a potent anti-angiogenic activity in vitro. In U-87 MG glioblastoma cells, TTAC-0001 significantly inhibited the phosphorylation of VEGFR2/KDR mediated by VEGF. To reveal in vivo efficacy, we have tested TTAC-0001 in glioblastoma and colorectal xenograft models. We demonstrated that antitumor activity of TTAC-0001 in preclinical models correlated with induction of growth arrest and apoptosis as well as the inhibition of angiogenesis. Currently, we are evaluating the combination of TTAC-0001 with chemotherapeutic agents in xenograft models. A single dose study performed in mouse allowed us to establish the relationship between the pharmacokinetics (PK) and efficacy of TTAC-0001. Taken together, our data suggest that targeting VEGFR2 pathway by TTAC-0001 would be a promising candidate for the treatment of cancer. (This study was supported by grants of the Korea Healthcare technology R&D Project, Ministry for Health & Welfare Affairs (A092255 and A040016) and Advanced Medi-cluster R&D Project, DaejeonTechnoPark, Republic of Korea. Seol HJ and Nam DH are co-corresponding authors for this manuscript.)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 647. doi:10.1158/1538-7445.AM2011-647
Abstract 659: Inhibiting autophagy improves the efficacy of VN/12-1 over all-trans retinoic acid in a HER2 over-expressing SK-BR3 breast cancer xenograft model
Authors: Godbole Abhijit M. , Purushottamachar Puranik , Gediya Lalji , Njar Vincent C.O.
Published: June 2012

Purpose: Autophagy is a critical physiological process of cell survival in the presence of stress and is an important cause of resistance to anti-cancer therapy. Drugs that inhibit autophagy (e.g. chloroquine) deprive the cells of this protective mechanism and therefore are promising agents in a combination therapy of breast cancer. Our group has designed and synthesized a novel retinoic acid derivative, VN/12-1. We reported previously that VN/12-1 is a potent inducer of autophagy in estrogen independent, HER2 over-expressing breast cancer cell line SK-BR3 in vitro. In the present study, we used chloroquine in combination with VN/12-1 in an SK-BR3 xenograft model to test the hypothesis that the combination of VN/12-1 and chloroquine would result in greater efficacy against SK-BR3 tumors compared to VN/12-1 alone or all-trans retinoic acid (ATRA) alone.

Experimental Design: To test this hypothesis, 64 female SCID mice (8 mice per group) were inoculated with SK-BR3 cells. Once the tumors formed, the mice were treated with vehicle (control), VN/12-1 and ATRA alone or in combination with chloroquine for 30 days. The two dosages of VN/12-1 for the groups involving VN/12-1 were 2.5 mg/kg and 5 mg/kg. The doses of ATRA and chloroquine were 5 mg/kg and 50 mg/kg, respectively. All the agents were administered subcutaneously (s.c) twice a week.

Results: Out of all the treatment groups, both the dosages of VN/12-1 (2.5 mg/kg and 5mg/kg) when used in combination with chloroquine were the most effective in inhibiting the growth of SK-BR3 tumors (70% and 80% growth inhibition respectively compared to vehicle control). The combination of ATRA with chloroquine did not show statistically significant inhibition of tumor growth. The effect of each treatment on the body weight and the weights of uteri was also determined. No toxicities were observed as noted by no significant changes in the weight of the mice. The data about the tumor samples’ analysis for the effect of each treatment on the expression of various tumor markers and autophagy markers and pharmacokinetic studies on VN/12-1 will be presented.

Conclusion: Our studies have demonstrated for the first time that the combination of VN/12-1 and chloroquine can be used to treat estrogen independent breast cancer. It is hoped that this combination therapy would solve the problem of the development of acquired resistance due to autophagy that typically follows therapeutic treatment of breast cancer. We envision further advanced preclinical development of this combination therapy as potential therapy for breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 659. doi:10.1158/1538-7445.AM2011-659
Abstract 670: Bis-nitrophenylphosphate (BNPP) but not phenylmethylsulfonyl fluoride (PMSF) inhibits the activation of the novel anti-cancer pro-drug CZ48
Authors: Markides Constantine S.A , Olszewski Alexa P. , DeJesus Albert , Vardeman Kyle B. , Moore Lauren E. , Vardeman Dana M. , Giovanella Beppino C.
Published: June 2012

CZ48, the 20-O-propionate ester of Camptothecin (CPT), is a non-toxic prodrug of CPT first described by Cao et al. (1998). The propionate side-chain is enzymatically cleaved in target tissues. This gives rise to CPT, an inhibitor of Topoisomerase I, which then blocks cell division causing selective tumor toxicity.

We have previously established the preferential activation of CZ48 in tumor tissues compared to normal tissues and an ultra sensitive assay to detect it (2009). The present studies explore the specifics of that activation in vitro using both cells in culture and surgically removed xenografted tumors from nude mice.

DOY lung adenocarcinoma was grown subcutaneously in nude mice and then surgically excised, homogenized and serially centrifuged to produce specific subcellular fractions. The bulk of esterase activity was found to be concentrated in the cytosol, while the microsomal fraction showed minimal activity. All other fractions tested were below the limit of detection.

HT-29 colon carcinoma cells were grown in culture in the presence and absence of varying concentrations of bis-nitrophenylphosphate (BNPP), a potent inhibitor of carboxylesterase and butyrylcholinesterase (BChE), in an attempt to find the highest possible non-toxic concentration to the cells. This concentration was then included during a 7-day IC50 determination for CZ48. In the presence of BNPP, the IC50 of CZ48 increased 4-fold from 181.4 nM to 710.8 nM. In vitro conversion of CZ48 to CPT by cytosolic fraction of a HT-29 tumor xenograft grown subcutaneously in nude mice was decreased by BNPP in a dose dependent manner. In contrast, the serine protease and carboxylesterase inhibitor phenylmethylsulfonyl fluoride (PMSF) and other esterase inhibitors did not affect the activation of CZ48.

Purified butyrylcholinesterase and acetylcholinesterase (SigmaAldrich, St. Louis MO) did not show any capacity to activate CZ48.

In conclusion, the enzymatic activation of CZ48 is not mediated by butyrylcholinesterase but by another cytosolic enzyme inhibitable by BNPP.

These data constitute a significant step forward in unraveling the exact mechanism for the activation of CZ48. This will help design a pre-treatment assay to establish tumor sensitivity, as well as give us direction for designing new, more potent prodrugs.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 670. doi:10.1158/1538-7445.AM2011-670
Abstract 679: NDC-1308 nanoparticles inhibit tumor growth by novel mechanisms controlling cancer cell proliferation
Authors: Nye Steven H. , Weitman Steven , Yarger James
Published: June 2012

It has previously been demonstrated that treatment of tumor cells with an estrogen receptor beta (ER-β) agonist can lead to cessation of cell division and cell death. We recently reported the discovery of NDC-1308, a member of our estradiol-related family of ER-β agonists, which is cytotoxic to a broad range of human tumor cell lines (EC50 is 5-20 uM). Although NDC-1308 has similar binding affinity for ER-α and ER-β (70-100 nM), functional studies show that it activates ER-β about 5-fold more compared to ER-α. To understand the mechanism of cytotoxicity, A549 (lung), SKOV-3 (ovary), and Panc-1 (pancreatic) human tumor cell lines were treated with NDC-1308 and gene expression changes evaluated by microarray. In all cell lines, NDC-1308 caused a significant down-regulation of key genes critical for chromosome replication, along with the up-regulation of at least two nucleases, granzyme K (GzmK) and apoptosis enhancing nuclease (AEN). There was also a significant up-regulation of pro-apoptotic pathway genes including BBC3 and GDF15 and an up-regulation of a death receptor pathway gene TNFRSF10B (DR5). These results suggest that ER-β activation by NDC-1308 may be useful to trigger DNA damage, cell cycle arrest and ultimately the death of cancer cells. However, PK studies in rodents showed that NDC-1308 has a short half-life, thereby lowering its potential efficacy as a cancer therapeutic. In order to optimize the blood circulation time and to enhance the accumulation of NDC-1308 in tumors, the drug was formulated into several different types of nanoparticles (50-100 nm), including an amorphous drug particle, a lipid-containing particle and a micelle-based particle. Whole body imaging studies showed that NDC-1308 nanoparticles conjugated with AlexaFluor 750 could localize to human tumors such as colon adenocarcinomas, renal cell carcinomas and lung adenocarcinomas in nude mice (N=4 per tumor type). To determine the efficacy of NDC-1308 as an anti-cancer therapy, nude mice bearing A549 human tumors (N=12 per group) were dosed every other day with NDC-1308 nanoparticles (up to 24 mg/kg of the active drug) via tail vein injection. During treatment, this led to a significant, dose-dependent reduction in tumor size in drug treated animals versus untreated controls. We conclude that intravenous administration of NDC-1308 nanoparticles can inhibit the rate of human tumor growth in a mouse model of cancer. Our future development plans include large animal safety and toxicity studies, followed by IND submission and Phase 1 clinical trials.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 679. doi:10.1158/1538-7445.AM2011-679
Abstract 714: A potential epigenetic regulation of PDGFRβ overexpression in melanomas acquiring resistance to PLX4032
Authors: Nazarian Ramin , Ferrari Roberto , Kong Xiangju , Kurdistani Siavash K. , Lo Roger S.
Published: June 2012

Activating B-RAF V600E kinase mutations occur in ∼7% of human malignancies and ∼60% of melanomas. Clinical experience with a novel B-RAF inhibitor, PLX4032, demonstrated an unprecedented 80% anti-tumor response rate among patients with V600EB-RAF-positive melanomas, but acquired drug resistance frequently develops after initial responses. In previous work, we showed that PLX4032 acquired resistance does not occur by V600EB-RAF secondary mutations. Instead, resistant melanomas develop mutually exclusive upregulation of PDGFRβ (activating MAPK-alternative survival) or N-RAS (reactivating MAPK). PDGFRβ over-expression at the RNA and protein levels does not result from genomic DNA copy number gain or correlate with mutational activation, suggesting a non-genetic cause. In contrast to N-RAS-upregulated, PLX4032-resistant cells, PDGFRβ-upregulated, PLX4032-resistant melanoma (PPRM) cell lines display a global switch in cellular morphology and gene expression patterns when compared to their drug-sensitive, parental counterparts. Specifically, this switch involves a loss of melanocytic differentiation and a gain of epithelial-to-mesenchymal gene expression. We show that PLX4032 and the HDAC inhibitor LBH589 (panobinostat) rapidly and reversibly control the levels of PDGFRβ RNA and protein. We thus used PPRM cell lines and short-term cell culture to dissect a potential epigenetic mechanism of PDGFRβ over-expression. In ChIP assays, PPRM cell lines and culture, when treated with LBH589, displayed significant deacetylation of histone H3K9, H3K18 and H4K16 in conserved acetylation peaks in the PDGFRβ gene body. Continued progress in characterizing this potential epigenetic pathway of PLX4032 acquired resistance may reveal novel therapeutic opportunities.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 714. doi:10.1158/1538-7445.AM2011-714
Abstract 715: TGF-beta blockade improves the distribution and efficacy of chemotherapeutic agents in breast carcinoma
Authors: Liu Jieqiong , Liao Shan , Diop Benjamin , Chen Wei , Goel Shom , Huang Yuhui , Boucher Yves , Jain Rakesh K. , Xu Lei
Published: June 2012

Although the role of TGF-β has been studied extensively, its impact upon drug delivery within tumors remains poorly understood. In this study, we blocked the TGF-β pathway in mouse models of breast cancer and studied the effect on delivery and efficacy of chemotherapeutics. We used both genetic (overexpression of sTβRII, a soluble TGF-β type II receptor) and pharmaceutical (1D11, a TGF-β antibody) approaches to block the TGF-β signaling in two orthotopic breast cancer models (human MDA-MB-231 cells and murine 4T1 cells). TGF-β blockade significantly decreased the growth and metastasis of orthotopic human breast carcinoma xenografts. In addition, TGF-β blockade increased the recruitment and incorporation of myofibroblasts into tumor blood vessels and restored vascular perfusion. Moreover, TGF-β blockade normalized the tumor extracellular matrix (ECM) by decreasing collagen I content. As a result of this vessel and ECM normalization, TGF-β blockade improved the transvascular and interstitial transport of both small and large molecular weight chemotherapeutic agents, and consequently enhanced their efficacy. In conclusion, our study shows that TGF-β blockade might represent a new approach to improve delivery of both low molecular weight conventional drugs as well as nanomedicines in order to maximize therapeutic outcomes.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 715. doi:10.1158/1538-7445.AM2011-715
Abstract 722: Acquired resistance to vorinostat in acute myeloid leukemia
Authors: Dupéré-Richer Daphné , Retrouvey Hélène , Pettersson Filippa Pettersson , Miller Wilson Miller
Published: June 2012

Histone deacetylase inhibitors (HDACi) have recently emerged as promising anticancer agents. Some HDACi have advanced into Phase II and III clinical trials, both as a single agent and in combination with cytotoxics for a variety of malignancies. Encouraging results have been obtained in acute myeloid leukemia (AML). However, HDACi target many pathways and the full mechanism responsible for their anti-neoplastic activity is still far from clear. An understanding of the molecular mechanisms underlying resistance to HDACi may help to elucidate their mechanism of action and may be of relevance in an attempt to design more effective combination strategies.

The purpose of this study is to understand the molecular alterations associated with resistance to vorinostat (Zolinza®).

A vorinostat resistant clone (U937-VR) was derived from the AML cell line U937 using a dose escalation protocol. The vorinostat-resistant cells (U937-VR) are able to grow in 2 µM vorinostat without induction of apoptosis. U937-VR cells are cross-resistant to the cytotoxic effects of other HDACi, as measured by propidium iodide staining and caspase 3/7 activation. Using western blot, we observed that vorinostat exposure increases tubulin acetylation in U937-VR cells while being incapable of inducing histone acetylation. These data demonstrate effective drug import into the cells, an event that is otherwise commonly altered in drug resistant cells. Furthermore, western blotting reveals a drastic difference in the protein level of the histone acetyltransferase CBP (CREB binding protein) between VR-U937 and parental U937 cells, whereas no alterations in the protein levels of the main HDACs targeted by vorinostat is seen. This indicates that the balance between HDAC and HAT activity might be perturbed.

Finally, the resistance index (the ratio between the LD50 of resistant and sensitive cells) of different drugs was evaluated by measuring apoptosis using propidium iodide staining. U937 parental and U937-VR cells have equivalent LD50 for the DNA damaging agent cisplatin and for the microtubule stabilizing agent taxol. In contrast, we observed that U937-VR cells exhibit increased sensitivity toward the proteasome inhibitors MG132 and Bortezomib. This increased sensitivity correlates with a higher level of ubiquitinated protein accumulation in U937-VR.

Cumulatively, our data suggest that the U937-VR cells are not multidrug resistant and that the apoptotic cascade remains functional. The importance of the alteration in HAT level and the acquired sensitivity to proteasome inhibitor by chronic exposure to HDACi need further investigation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 722. doi:10.1158/1538-7445.AM2011-722
Abstract 769: Novel cancer immunotherapeutics utilizing targeting peptides
Authors: Diaz Tracy M. , McGuire Michael J. , Brown Kathlynn C.
Published: June 2012

Cancer immunotherapeutics is an emerging treatment option that offers high tumor specificity and efficacy while reducing deleterious side effects. Immune therapies for cancer can be divided into two main types: active and passive. Active therapy strives to achieve a long term protective immunity against a tumor antigen while passive therapy supplies exogenous immunological reagents to provide specific anti-tumor effector functions. Both immunotherapies can be improved through the use of targeting peptides. Our lab utilizes a phage library panning method for isolation of cell-specific peptides that can be rapidly acquired without prior knowledge of cell surface receptors.

Active Immunotherapy: Cancer vaccines can elicit an immune response against tumor associated antigens that will result in tumor reduction and protective immunity. Recent studies have utilized antigen-pulsed in vitro matured DCs during vaccination for a more effective anti-cancer immune response. Several clinical trials, however, show that this method does not provide a significant therapeutic immune response. A more robust anti-tumor immune response could potentially be achieved through in vivo targeting of tumor antigens to DCs. Through the phage library panning protocol, our lab has identified 2 phage clones, XS52.1 and XS52.3, which have been shown to specifically bind to the XS52 immature dendritic cells. The XS52.3 phage clone has been further shown to bind bone marrow dendritic cells (BMDCs) from both Balb/c and C57BL/J6 mice. While current data suggests these phage clones are capable of binding DCs in vitro, future studies will determine if these peptides can be used to target antigen to DCs in vivo for vaccination.

Passive Immunotherapy: Monoclonal antibodies directed against tumor associated antigens have been successfully used in clinical settings, but problems remain with identifying and validating new antigen targets. Modification of the antibody scaffold for distinct applications can also be problematic. Using our phage display panning protocol, we have identified ligands of high affinity and specificity against a panel of human non-small cell lung cancer (NSCLC) cell lines. Furthermore, these peptide targeting ligands can be chemically synthesized and easily modified for different uses. For example, synthetic peptide ligands have been used to direct antibody dependant cellular cytotoxicity through the use of biotinylated tetrameric peptides and anti-biotin antibodies. These results suggest that peptide targeting ligands can be used to direct antibody effector functions for passive immunotherapy against cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 769. doi:10.1158/1538-7445.AM2011-769
Abstract 800: Inflammatory chemokines mediate immune surveillance of intestinal cancer
Authors: Jala Venkatakrishna R. , Mathis Steven P. , Bodduluri Sobha R. , Maturu Paramahamsa , Krishnan Elangovan , Smith Michelle E. , Chilton Paula M. , Mitchell Thomas C. , Locati Massimo , Mantovani Alberto , Bodduluri Haribabu
Published: June 2012

Immune system plays a dual role in cancer development and progression. Under conditions of chronic inflammation the repair response initiated by the immune system strongly promotes tumor growth. Epidemiological evidence of increased cancer incidence in organ transplant recipients and immune compromised individuals suggests a critical role for immune surveillance in keeping cancer under control. The cellular and molecular mechanisms that control tumor promoting chronic inflammation or tumor suppressing immune surveillance are unclear. Chemokines direct the migration of leukocytes to the sites of infection or injury and therefore are likely to play a central role in perpetuating tumor promoting chronic inflammation as well as orchestrating tumor eradicating immune surveillance.

D6 is a chemokine decoy receptor and an effective scavenger of inflammatory CC-chemokines. D6-knockout (D6-/-) mice showed enhanced inflammation in different models including carcinogen-induced inflammation-promoted skin cancers. In this study, we show that D6-/- mice when bred onto mice with a heterozygous mutation in the adenomatous polyposis coli (ApcMin/+) gene demonstrated reduced intestinal tumor burden and increased survival. A decrease in tumor promoting inflammation is coincidental with increased mast cells and CD8+ T cell activation profiles in tumors from the D6-/-ApcMin/+ mice compared to ApcMin/+ mice. The D6-/-ApcMin/+ mice in the context of the lymphocyte deficient, Rag2-/-background (Rag2-/-D6-/-ApcMin/+), showed a significant increase in tumor burden that is reversed by the adoptively transferred CD8+ and/or CD4+T-lymphocytes from the D6-/-ApcMin/+ mice. Chemokine levels in serum and chemokine receptor expression patterns on lymphocytes from the ApcMin/+ and D6-/-ApcMin/+ mice and the Rag2-/-D6-/-ApcMin/+ mice undergoing adoptive transfer treatments identified the increased levels of ligand-receptor pairs of LTB4/BLT1, CCL2/CCR2, and CXCL9/CXCR3 being critical in promoting tumor suppressive immune surveillance in this spontaneous tumor model. These results show that inflammatory chemokines play a protective role against progression of intestinal cancers by immune surveillance.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 800. doi:10.1158/1538-7445.AM2011-800
Abstract 810: Dietary grape seed proanthocyanidins inhibit UV-induced immunosuppression through stimulation of CD8+ effector T cells and inactivation of regulatory CD4+ T cells
Authors: Vaid Mudit , Singh Tripti , Sharma Samriti , Li Anna , Elmets Craig A. , Xu Hui , Katiyar Santosh K.
Published: June 2012

The immunosuppressive effects of solar ultraviolet (UV) radiation, particularly UVB (290-320 nm), are well recognized. Experimental evidence indicates that UV-induced immunosuppression is a risk factor for skin cancer development, including melanoma and non-melanoma, in mice and clinical evidence suggests that it is also a risk factor in humans. Conversely, animals with an enhanced immune response exhibit a lower risk of skin tumor development on chronic UV exposure. Dietary grape seed proanthocyanidins (GSPs) have been shown to inhibit UVB-induced immunosuppression in mice; however, the cellular and molecular mechanisms underlying this inhibitory effect of GSPs are not yet clearly understood. To characterize the cell population responsible for the GSPs-mediated inhibition of UVB-induced immunosuppression, we used an adoptive transfer approach. Splenocytes and draining lymph nodes were harvested from mice that had been administered dietary GSPs, exposed to UVB, and sensitized by topical application of 2,4-dinitorfluorobenzene (DNFB) onto the UVB-exposed skin. CD8+ and CD4+ T cells were positively selected and transferred into naïve mice that were subsequently challenged by application of DNFB on the ear skin. Naïve recipients that received CD8+ T cells from GSPs-treated, UVB-irradiated donors exhibited full contact hypersensitivity (CHS) response. CHS is considered to be a prototypic T-cell mediated immune response. Naïve mice that received CD4+ regulatory T cells from GSPs-treated, UVB-exposed mice were able to mount a CHS response after sensitization and subsequent challenge with DNFB. On culture, the CD8+ T cells from GSPs-treated, UVB-exposed mice secreted higher levels of Th1 cytokines (IL-2, IFNγ) than CD8+ T cells from UVB-irradiated mice not treated with GSPs. CD4+ T cells from GSPs-treated, UVB-exposed mice secreted significantly lower levels of Th2 cytokines (IL-4 and IL-10) than CD4+ T cells from UVB-exposed mice not treated with GSPs. These data suggest that dietary GSPs inhibit UVB-induced immunosuppression by stimulating CD8+ effector T cells and diminishing regulatory CD4+ T cells in mice. This property of GSPs can be used as an alternative strategy to augment the induction of CD8+ effector T cells and to diminish the development of CD4+ regulatory T cells and that may lead to the prevention of skin cancer risk in humans.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 810. doi:10.1158/1538-7445.AM2011-810