bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1666: Suppression of cyclooxygenase-2 by dual-specificity phosphatase-2 ameilorates cancer malignancy
Authors: Li Yo-Hua , Lin Shih-Chieh , Tsai Shaw-Jenq
Published: May 2015

Aberrant production of cyclooxygenase-2 (COX-2) and COX-2-derived prostaglandin E2 (PGE2) have been demonstrated to contribute to tumor development and malignancy in many human cancers. However, the initiating factor responsible for maintaining high levels of COX-2 expression during cancer development remains enigmatic. We hypothesize that aberrant expression of COX-2 in cancer cells is initiated by hypoxia, a common phenomenon occurs in very early stage during cancer development. Herein, we present data demonstrating that levels of COX-2 in cancer cells are induced by hypoxia in a hypoxia-inducible factor-1α (HIF-1α)-dependent manner. Intriguingly, HIF-1α does not directly induce COX-2 promoter activity. In contrast, induction of COX-2 expression is mediated by HIF-1α-induced downregulation of dual specificity phosphatase-2 (DUSP-2), a MAPK-specific phosphatase. Forced expression of DUSP2 reduces the levels of COX-2, while knockdown of DUSP2 induces COX-2 expression in cancer cells. Moreover, depletion of DUSP2 also induces the expression of microsomal prostaglandin E synthase (mPGES) and consequently increases the production of PGE2. Further study reveals that re-induction of DUSP2 abolishes hypoxia-induced COX-2 expression and PGE2 production. To test the hypothesis that COX-2 mediates loss-of-DUSP2-induced tumorigenesis, a selective COX-2 inhibitor, NS-398, was used to block the function of COX-2 in the DUSP2-knockdown xenograft mouse model. Knockdown of DUSP2 markedly enhances tumor growth while treatment with NS-398 reverses loss-of-DUSP2-induced tumor development in vivo. Taken together, our data indicate that DUSP2, a negative regulator of COX-2, plays a critical tumor suppressive role and hypoxia, a common stress during cancer development, suppresses DUSP2 to initiate COX-2 overexpression and promote cancer progression. Our findings suggest that preventing DUSP2 from hypoxia-mediated downregulation or re-induction of DUSP2 during cancer development may represent a potential approach for cancer therapy.

Citation Format: Yo-Hua Li, Shih-Chieh Lin, Shaw-Jenq Tsai. Suppression of cyclooxygenase-2 by dual-specificity phosphatase-2 ameilorates cancer malignancy. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1666. doi:10.1158/1538-7445.AM2014-1666
Abstract 1672: Tumor educated B cells acquire immune suppressive function and promote tumor growth
Authors: Zhang Yu , Morgan Richard , Shin Seung-uon , Cho Hyun-Mi , Albayati Ahmed , Pimentel Augustin , Rosenblatt Joseph D.
Published: May 2015

B lymphocytes may play a role in inhibiting the immune response against certain tumors, but the underlying mechanisms by which B cells facilitate tumor growth are poorly understood.

Murine EMT-6 mammary tumors grow readily in wild type mice (WT) but are rejected or grow very poorly in B-cell deficient μ-/- BALB/c mice (BCDM). Relative to BCDM, B cell reconstituted BCDM demonstrate enhanced tumor growth, marked expansion of Tregs in response to EMT-6 implantation, increased infiltration of both B cells and Tregs into tumor, and a markedly reduced cytolytic T cell response. Markedly decreased levels of CD49b+ NK cell and CD8+ T cell infiltration into the tumor bed were seen in WT or in B cell reconstituted BCDM, compared to levels of infiltration seen in BCDM. Adoptive transfer of either IL-10-/- B cells or MHC-II-/- B cells into BCDM also promoted tumor growth and expansion of Treg and suppressed cytotoxic CD8+ T cell anti-tumor activity and IFN-γ production in vivo. We hypothesized that tumor infiltrating B cells promote Treg expansion but also may directly suppress T cell activation and proliferation due to acquired regulatory function.

In vitro co-culture of EMT-6 tumor cells with naïve B cells generated B cells of a distinct phenotype (PD-L1hiCD86hiIAdhiCD62LhiLAP+CD44lo but CD25-CD69-CD80-). EMT-6 co-cultured B cells markedly suppressed naïve CD4 T cell proliferation. Flow cytometric analysis of tumor infiltrating B cells (TIL-B) revealed that at day 21 post tumor implantation, TIL-B cells are LAPhiCD62LhiCD86hiIAdhiPD-L1hiCD44+CD25-. LAP/TGF-β expression on TIL-B cells was gradually upregulated as tumor burden increased, from 2∼3% on day 8 to ∼50% of infiltrating B cells by day 21. In contrast, splenic B cells at day 21 did not express LAP/TGF-β. TIL-B cells also markedly suppressed CD4+ T cell proliferation in-vitro when compared to splenic B cells.

Our studies indicate that the T cell anti-tumor response is enhanced in the absence of B cells, due to acquisition of a suppressive immmunoregulatory phenotype by migrating B cells following tumor infiltration. We are currently looking for evidence of human correlates of B regulatory activity observed in murine models.

Citation Format: Yu Zhang, Richard Morgan, Seung-uon Shin, Hyun-Mi Cho, Ahmed Albayati, Augustin Pimentel, Joseph D. Rosenblatt. Tumor educated B cells acquire immune suppressive function and promote tumor growth. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1672. doi:10.1158/1538-7445.AM2014-1672
Abstract 1674: Humanized mouse models for personalized preclinical testing of monoclonal antibodies targeting immune checkpoints
Authors: Baia Gilson S. , Vasquez David , Ciznadija Daniel , Wilkinson Brandy , Sidransky David , Katz Amanda , Paz Keren
Published: May 2015

The blockade of immune checkpoints with monoclonal antibodies (mAbs) is a promising therapeutic avenue, with durable objective responses observed in patients with solid tumors, particularly melanoma, non-small cell lung cancer (NSCLC) and renal cell carcinoma. Preclinical models that recapitulate a functional human immune system will therefore be essential tools for the continued investigation of immunotherapy approaches. Champions Oncology is engaged in advanced personalized solutions and our TumorGraft models have been developed and extensively characterized as a platform for use in personalizing cancer patient care, as well as pharmaceutical development. However, because TumorGrafts are established by engrafting patient tumors into immune-deficient mice, the therapeutic efficacy of immune-modulatory drugs cannot be directly examined. To circumvent this limitation, we reconstituted the human immune system by engrafting human hematopoietic cells (HLA-A2; CD34+) into immune-compromised mice (PrkdcscidIl2rgtm1Sug) carrying the scid mutation and a targeted mutation of the Il2r-gamma gene. Ten to twelve weeks later, mature CD45+ human T cells could be detected in these mice, at which time TumorGrafts were established, followed by drug-sensitivity testing with various mAbs targeting the immune system. Fifty six well-established melanoma, colorectal, breast and lung TumorGraft models were characterized and selected with regard to their HLA type and other molecular characteristics such as BRAF mutation status (in melanoma) and KRAS mutation status (in colorectal and lung cancer) as well as expression of PD-L1. With the present study, we demonstrated the potential of combining the humanized mouse with Champions TumorGraft to generate a preclinical platform for assessing the therapeutic value of mAbs targeting immune checkpoints in various solid tumors.

Citation Format: Gilson S. Baia, David Vasquez, Daniel Ciznadija, Brandy Wilkinson, David Sidransky, Amanda Katz, Keren Paz. Humanized mouse models for personalized preclinical testing of monoclonal antibodies targeting immune checkpoints. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1674. doi:10.1158/1538-7445.AM2014-1674
Abstract 1675: Variations in the composition of inflammatory infiltrates are associated with persistence or regression of bronchial dysplasia
Authors: O'Keefe Mary C. , Dwyer-Nield Lori , Edwards Michael , Keith Robert L. , Franklin Wilbur A. , Sugita Michio , Miller York E. , Friedman Micah , Tennis Meredith , Choo Kevin S. , Hickey Gregory , Porter Jeannine , Wilson Storey , Osypuk Andrea , Weiser Mary , Bokhoven Adrie van , Geraci Mark , Nemenoff Raphael , Merrick Daniel T.
Published: May 2015

INTRODUCTION: The clinical course of dysplastic bronchial lesions is variable. While some regress, others progress to invasive carcinoma. We sought to identify how variations in inflammatory infiltrates might influence the clinical outcome of dysplastic bronchial lesions.

METHODS AND RESULTS: Gene expression microarray analyses identified 318 genes that distinguish persistent from regressive bronchial dysplastic lesions. Pathway analysis utilizing this genelist was performed using Ingenuity© software. Gene expression data showed several inflammation related pathways with statistically different levels of activity in persistent versus regressive lesions. Expression of genes associated with CD4 positive T-cells and HLA-DRA positive macrophages were both increased in regressive lesions. To further investigate these findings, a similar set of progressive and regressive lesions were selected for immunohistochemical (IHC) analysis. For each biopsy, IHC for T-cell markers CD3, CD4 and CD8 and macrophage marker CD68 was performed. Immunohistochemically positive inflammatory cell subsets were counted in a single high power field corresponding to the focus of maximum inflammation. For each marker, separate counts for epithelium and stroma-associated inflammation were performed. Preliminary IHC data (n=6) shows a strong trend towards increased numbers of macrophages in the dysplastic epithelium of regressive lesions (4.6 fold increase, p=0.082).

CONCLUSION: Our findings suggest that differences in inflammatory cell subsets may distinguish persistent and regressive bronchial dysplasia. Preliminary data points to CD4 positive T-cells and intraepithelial macrophages as differentiating factors that correlate with regression.

Citation Format: Mary C. O'Keefe, Lori Dwyer-Nield, Michael Edwards, Robert L. Keith, Wilbur A. Franklin, Michio Sugita, York E. Miller, Micah Friedman, Meredith Tennis, Kevin S. Choo, Gregory Hickey, Jeannine Porter, Storey Wilson, Andrea Osypuk, Mary Weiser, Adrie van Bokhoven, Mark Geraci, Raphael Nemenoff, Daniel T. Merrick. Variations in the composition of inflammatory infiltrates are associated with persistence or regression of bronchial dysplasia. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1675. doi:10.1158/1538-7445.AM2014-1675
Abstract 1676: The HSP90 inhibitor 17-AAG improves chemoresistance of cisplatin-resistant esophageal squamous cell carcinoma cell lines
Authors: Ui Takashi , Morishima Kazue , Saito Shin , Sakuma Yuji , Fujii Hirofumi , Hosoya Yoshinori , Yasuda Yoshikazu , Niki Toshiro
Published: May 2015

[Background] Although cisplatin is a platinum drug that is widely used to treat esophageal squamous cell carcinoma, acquired chemoresistance develops during the course of treatment and is often the reason for treatment failure. Overcoming chemoresistance is essential for improving the outcomes of patients. Heat shock protein 90 (HSP90) is known to be overexpressed in various cancer cells, and its inhibition by small molecules, either alone or in combination, has shown promise in the treatment of solid malignancies. In the present study, we evaluated the synergistic effect of combining cisplatin with the HSP90 inhibitor, 17-N-allylamino-17-demethoxy geldanamycin (17-AAG), on two cisplatin-resistant human esophageal squamous cancer cell lines, KYSE30 and KYSE150.

[Results] The results obtained demonstrated the synergistic inhibitory effects of cisplatin and 17-AAG on the growth of KYSE30 and KYSE150 cells. Cell growth and cell number were more effectively reduced by the combined treatment with cisplatin and 17-AAG than by the treatment with either cisplatin or 17-AAG alone. Western blotting revealed that the combined action of cisplatin and 17-AAG cleaved poly (ADP-ribose) polymerase (PARP) and caspase 3. Time lapse imaging revealed that the activations of caspase 3/7 preceded the cell death induced by the combined treatment of cisplatin and 17-AAG. These demonstrated that the reductions in both cell growth and cell number were mediated by apoptosis. Time-course experiments showed that reductions in X-linked inhibitor of apoptosis protein (XIAP) and phosphorylated Akt were concomitant with apoptosis.

[Discussion] The results of the present study demonstrated that 17-AAG synergized with cisplatin and induced apoptosis in cisplatin-resistant esophageal squamous cell carcinoma cell lines, and also that modulation of the Akt/XIAP pathway may underlie this synergistic effect.

[Conclusion] Combination therapy with cisplatin and a HSP90 inhibitor may represent a promising strategy to overcome cisplatin resistance in esophageal squamous cell carcinoma.

Citation Format: Takashi Ui, Kazue Morishima, Shin Saito, Yuji Sakuma, Hirofumi Fujii, Yoshinori Hosoya, Yoshikazu Yasuda, Toshiro Niki. The HSP90 inhibitor 17-AAG improves chemoresistance of cisplatin-resistant esophageal squamous cell carcinoma cell lines. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1676. doi:10.1158/1538-7445.AM2014-1676
Abstract 1679: Inhibiting KRAS-reprogrammed glutamine metabolism sensitizes pancreatic cancer to NQO1-bioactivatable drugs
Authors: Chakrabarti Gaurab , Boothman David A.
Published: May 2015

Patients with pancreatic cancers have one of the highest mortality rates of any cancer with 5-year survival rates of 6%. The therapeutic responses of pancreatic cancers are highly variable and there is a desperate need for agents to specifically and efficaciously treat pancreatic cancer patients. We recently discovered that not only were NAD(P)H:quinone oxidoreductase 1 (NQO1) levels elevated 5- to 40-fold in >90% of pancreatic tumors vs associated normal tissue, but that catalase levels were inversely expressed comparatively, elevated in normal vs tumor tissue. NQO1 represents a unique target to exploit for the therapeutic elimination of pancreatic cancers. NQO1 bioactivatable drugs, such as β-lapachone (β-lap) or deoxynyboquinone (DNQ) and derivatives generate hydrogen peroxide as a mechanism to hyperactivate PARP1 and selectively kill tumors. In addition to catalase, reduced glutathione levels are essential for a cell's protection against hydrogen peroxide. Tumors with mutated KRAS, which constitutes >90% of pancreatic cancers, are metabolically reprogrammed to rely on glutamine to maintain the cell's NADPH and glutathione levels, and therefore, anti-oxidant state (Son et.al., Nature, 2013). The present study evaluated the therapeutic potential of inhibiting this KRAS-reprogrammed metabolic pathway with the small molecule GLS1 inhibitor, BPTES, in combination with NQO1-bioactivatable drugs, β-lapachone or IB-DNQ. Synergistic cell lethality was noted using non-lethal doses of BPTES combined with sublethal doses of β-lapachone in KRAS-driven pancreatic or non-small cell lung cancer cells. ROS levels in BPTES and β-lap treated cell lines were dramatically higher than the ROS levels with either agent alone. This was further supported by a dramatic loss of glutathione and NADPH following combination treatment vs either agent alone. Lethality was completely rescued by the addition of the NQO1 inhibitor, dicoumarol, demonstrating that synergy is dependent on the NQO1 activation of β-lap. Partial rescue was seen with the addition of cell permeable glutathione further demonstrating the importance of ROS in synergy. The addition of cell permeable malate and oxaloacetate, downstream metabolites of the KRAS-driven glutamine pathway, also rescued synergy. Our findings indicate that NQO1-bioactivatable drugs may improve the sensitivities of clinical grade GLS1 inhibitors in pancreatic cancer patients.

Citation Format: Gaurab Chakrabarti, David A. Boothman. Inhibiting KRAS-reprogrammed glutamine metabolism sensitizes pancreatic cancer to NQO1-bioactivatable drugs. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1679. doi:10.1158/1538-7445.AM2014-1679
Abstract 1681: Iron chelation therapy increased the anticancer effect of sorafenib in hepatocarcinoma
Authors: Urano Shinichi , Ohara Toshiaki , Katsube Ryoichi , Watanabe Shinichiro , Noma Kazuhiro , Tomono Yasuko , Tazawa Hiroshi , Nouso Kazuhiro , Shirakawa Yasuhiro , Fujiwara Toshiyoshi
Published: May 2015

[Purpose]

Iron overload is known to associate with the progression of chronic hepatitis and the increase risk of hepatocellular carcinoma (HCC). We have reported that iron depletion inhibited the cancer cell proliferation and reciprocally induced angiogenesis. Anti-angiogenic drug synergistically enhanced the anti-tumor effect in iron depletion condition. Sorafenib is molecular-targeting drug with anti-angiogenic effect in HCC. We hypothesized that iron depletion also enhanced the effect of sorafenib and investigated it.

[Experimental Design]

HepG2 and HLE (Human HCC cell line) were used in this study. We used sorafenib (NexavarTM) and an oral iron chilator, deferasirox (EXJADETM). The anti-cancer effect and mechanism were determined using cell viability assay, VEGF ELISA, Flow Cytometry, Western blot analysis and in vivo subcutaneous tumor model. In clinical cases, we retrospectively analyzed the relationship between sorafenib response and serum iron-related makers(n=58).

[Results]

In HepG2 and HLE cells, deferasirox suppressed the cancer cell proliferation by itself and increased the suppression of sorafenib. Deferasirox increased VEGF secretion of supernatant on dose dependent manner. In the analysis of combination therapy, cell cycle arrest and apoptosis was enhanced in the combination therapy by down-regulation of cyclinD1 and cyclinE and up-regulation of cleaved PARP. The suppression of HepG2 subcutaneous tumor was enhanced in the combination therapy. In clinical cases, sorafenib prolonged overall survival in TIBC high and Ferritin low group.

[Conclusion]

Iron depletion by deferasirox increased the anti-cancer effect of sorafenib in vitro and in vivo experiments. In clinical cases, sorafenib was also effective in iron deficient patients. These results suggested that iron depletion therapy can be a novel combination chemotherapy with sorafenib for hepatocarcinoma patients.

Citation Format: Shinichi Urano, Toshiaki Ohara, Ryoichi Katsube, Shinichiro Watanabe, Kazuhiro Noma, Yasuko Tomono, Hiroshi Tazawa, Kazuhiro Nouso, Yasuhiro Shirakawa, Toshiyoshi Fujiwara. Iron chelation therapy increased the anticancer effect of sorafenib in hepatocarcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1681. doi:10.1158/1538-7445.AM2014-1681
Abstract 1682: Metformin synergistically enhances antitumor efficacy of sorafenib in vitro
Authors: KO YUNMI , Choi Bo Ra , Lee Jun Ah
Published: May 2015

Background: Previously, we observed anti-tumor effect of sorafenib in osteosarcoma cells. However, a number of studies suggested that cancer cells might escape from the therapeutic effects of sorafenib though activation of mTOR pathways. Metformin displays significant growth inhibitory effects in several cancer cells by modulating AMPK/Akt/mTOR signaling pathway. We evaluated the effect of metformin in osteosarcoma cells as a single agent, as well as in combination with sorafenib.

Methods: The effects of metformin on proliferation, migration and apoptosis of osteosarcoma cells were evaluated using MTT, wound-healing and FACS analysis. To elucidate the mechanisms of cell growth inhibition induced by metformin, we investigated expression of several key signaling proteins in OS cells. The synergistic interactions of metformin and sorafenib were determined by calcusyn analysis.

Results: We found that metformin significantly decreased the cell survival, wound-healing capacity of OS cells. Metformin also markedly activated AMPK and decreased the expression of Akt, ERK1/2, mTOR and its downstream target markers. And we observed that addition of sorafenib enhanced antiproliferative and proapoptotic effects of metformin by synergistic modulation of AMPK/Akt/mTOR signaling pathway.

Conclusion: We found that metformin exerts therapeutic potentials in OS cells. Currently, studies are underway to evaluate the possibilities of using metformin as an adjuvant therapeutic agent for osteosarcoma, in combination with chemotherapeutic agents or radiotherapy.

Citation Format: YUNMI KO, Bo Ra Choi, Jun Ah Lee. Metformin synergistically enhances antitumor efficacy of sorafenib in vitro. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1682. doi:10.1158/1538-7445.AM2014-1682
Abstract 1683: Novel combination approach using platinum drugs and mitochondrial division inhibitor 1 (mdivi-1) overcomes platinum resistance by synergistically inducing mitochondrial outer membrane permeabilization (MOMP) and apoptosis independent of Drp1
Authors: Qian Wei , Wang Jingnan , Roginskaya Vera , McDermott Lee , Edwards Robert , Stolz Donna , Llambi Fabien , Green Douglas , Houten Bennett Van
Published: May 2015

Platinum based anticancer agents, including cisplatin, are among the most effective and widely used anticancer drugs. However, inherent and acquired resistance to these drugs in tumors lead to treatment failure. We found a class of thioquinazolinone derivatives, including the mitochondrial division inhibitor-1 (mdivi-1), that overcome both the inherent and acquired resistance to cisplatin in tumor cell lines and also in primary ovarian tumors isolated from cisplatin refractory patients. The combination of cisplatin and mdivi-1 produces synergistic effect in inducing rapid apoptosis. Using Drp1 (a mitochondrial fission protein and the reported target of mdivi-1) knockout MEF cells we demonstrated that the combination of cisplatin and mdivi-1 overcomes cisplatin resistance in a Drp1-independent manner. Mdivi-1 causes replication defects and its combination with cisplatin triggers synergistic increases of replication stress and DNA damage. Comparing the treatment with cisplatin and mdivi-1 alone, the combination of the two agents enhances mitochondrial apoptotic signaling by specifically upregulating the expression of a pro-apoptotic Bcl-2 family protein Noxa, which promotes Bax/Bak-mediated mitochondrial outer membrane permeabilization (MOMP). Intriguingly, the combination of cisplatin and mdivi-1 also causes mitochondrial swelling that triggers a Bax/Bak-independent MOMP. Thus, the combination of cisplatin and mdivi-1 activates two distinct mechanisms that converge on mitochondria contributing to the enhancement of MOMP. This novel combination represents a potential effective strategy in overcoming platinum drug resistance by combining cisplatin with compounds that together are able to trigger the coinitiation of Bax/Bak-dependent and-independent mitochondrial apoptotic signaling. (Work was supported by P30CA047904, UPCI and PA Dept of Health CURE program)

Citation Format: Wei Qian, Jingnan Wang, Vera Roginskaya, Lee McDermott, Robert Edwards, Donna Stolz, Fabien Llambi, Douglas Green, Bennett Van Houten. Novel combination approach using platinum drugs and mitochondrial division inhibitor 1 (mdivi-1) overcomes platinum resistance by synergistically inducing mitochondrial outer membrane permeabilization (MOMP) and apoptosis independent of Drp1. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1683. doi:10.1158/1538-7445.AM2014-1683
Abstract 1684: Histone deacetylase inhibition enhances Pemetrexed cytotoxicity through induction of apoptosis and autophagy in non-small cell lung cancer models
Authors: Trisciuoglio Daniela , Desideri Marianna , Luca Teresa D. , Martile Marta D. , Gabellini Chiara , Eramo Adriana , Maria Ruggero D. , Milella Michele , Bufalo Donatella Del
Published: May 2015

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide. Pemetrexed (PEM), a multi-target folate antagonist, has demonstrated targeted efficacy in NSCLC histological subtypes characterized by low thymidylate synthase (TS, one of PEM's molecular targets) expression.

Histone deacetylase inhibitors (HDACi) modulate the expression of multiple genes, including thymidylate synthase (TS), one of the main targets of Pemetrexed. Since high levels of TS have been linked to clinical resistance to Pemetrexed in non-small cell lung cancer (NSCLC), we investigated the molecular and functional effects of combined Pemetrexed and ITF2357, a class I/II HDACi currently in clinical trials as anti-cancer agents .ITF2357 reduced TS mRNA and protein expression, potentially affecting sensitivity to Pemetrexed. When the two drugs were used in combiation, their sequence of administration was critical in determining the pharmacologic response: in both NSCLC cell lines and LCSC, a strikingly synergistic reduction in cell viability was observed with the sequence Pemetrexed followed by ITF2357, in both adenocarcinoma and squamous cell carcinoma models. Cell death induced by the combination involved both apoptosis and autophagy. Genetic and pharmacological approaches provided an interesting link between these two pathways and showed that sequential Pemetrexed/ITF2357 causes a toxic form of autophagy with consequent activation of a caspase-dependent apoptotic program. In vivo experiments in NSCLC xenografts confirmed that sequential Pemetrexed/ITF2357 is feasible and results in increased inhibition of tumor growth and increased mice survival.

Overall, this data provide a strong rationale for the clinical development of sequential schedules employing Pemetrexed followed by HDAC inhibition in NSCLC.

Citation Format: Daniela Trisciuoglio, Marianna Desideri, Teresa De Luca, Marta Di Martile, Chiara Gabellini, Adriana Eramo, Ruggero De Maria, Michele Milella, Donatella Del Bufalo. Histone deacetylase inhibition enhances Pemetrexed cytotoxicity through induction of apoptosis and autophagy in non-small cell lung cancer models. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1684. doi:10.1158/1538-7445.AM2014-1684
Abstract 1685: HER2 upregulation induced by gemcitabine treatment augments antitumor effect of trastuzumab emtansine against pancreatic cancer
Authors: Kan Shin , Koido Shigeo , Okamoto Masato , Hayashi Kazumi , Ito Masaki , Kamata Yuko , Komita Hideo , Nagasaki Eijiro , Homma Sadamu
Published: May 2015

[Background]

Although human pancreatic cancer (PC) frequently expresses human epidermal growth factor receptor type 2 (HER2), Trastuzumab has not provided sufficient therapeutic effect on PC probably due to low HER2 expression level. Recently we discovered HER2 expression of human PC cell lines was enhanced by gemcitabine (GEM) treatment. Furthermore, Trastuzumab Emtansine (T-DM1), Trastuzumab conjugated with a cytotoxic agent, showed promising results in breast cancer therapy. We investigated the possibility of new molecular targeting therapy against PC by combined treatment with GEM and T-DM1.

[Materials and Methods]

HER2 expression was analyzed by quantitative Real Time-PCR, western blotting and flowcytometry. The cell proliferation was examined by spectrophotometry using the counting reagents. T-DM1 was provided by Genentech Inc. T-DM1 bindinig to HER2 on PC cell surface was analyzed by flowcytometry.

[Results]

GEM treatment enhanced HER2 expression at around two fold in three out of five human PC cell lines. GEM was the most potent agent to enhance HER2 expression of PC cells among the standard chemotherapeutic agents for PC treatment. T-DM1 binding to HER2 on GEM-treated MiaPaca-2 cells was increased in accordance with the up-regulation of HER2 expression. Combined treatment with GEM and T-DM1 synergistically inhibited the cell growth of MiaPaca-2, and this cytotoxic effect was inhibited by adding to Trastuzumab which did not show direct cytotoxic activity to PC cells.

[Conclusions]

GEM treatment enhances HER2 expression of PC cells which promotes T-DM1 binding to HER2 on PC cells. Combined treatment with GEM and T-DM1 might become a promising modality against HER2 positive PC.

Citation Format: Shin Kan, Shigeo Koido, Masato Okamoto, Kazumi Hayashi, Masaki Ito, Yuko Kamata, Hideo Komita, Eijiro Nagasaki, Sadamu Homma. HER2 upregulation induced by gemcitabine treatment augments antitumor effect of trastuzumab emtansine against pancreatic cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1685. doi:10.1158/1538-7445.AM2014-1685
Abstract 169: Maintenance of breast cancer stem cells in an inert matrix is mediated by mesenchymal stem cells in the tumor stroma
Authors: Sarvestani Samaneh K. , Barati Danial , Jabbari Esmaiel
Published: May 2015

Introduction: Cancer stem cells (CSCs) hypothesis relates cancer recurrence to a small population of tumor cells with the ability to self-renew to maintain the tumor mass. Recent studies demonstrate that conventional therapies eliminate the differentiated cells that form bulk of the tumor, while leaving CSCs unharmed. There is increasing evidence that the maintenance of CSCs in the tumor tissue is regulated by microenvironment. In particular, human mesenchymal stem cells (hMSCs) and associated soluble factors as part of the tumor stroma play a significant role in self-renewal and maintenance of CSCs (1). Our laboratory has developed an inert 3D synthetic matrix with defined properties that maintains and enriches the CSC sub-population of tumor cells within a certain range of stiffness (2). The objective of this work was to investigate the effect of co-encapsulation of MDA-MB-231 (MDA) human breast cancer cells with human hMSCs in the engineered patterned matrix on tumorsphere formation and CSC maintenance.

Methods: Thee effect of MSCs on MDA cells was investigated in a patterned matrix with defined stiffness to control tumorsphere size. To separate the patterned cellular matrix from the glass substrate, a layer of the gel without cells was first crosslinked on the glass substrate by UV radiation. Next, a mixture of MDA and hMSCs (5x105 cells/mL each) in the hydrogel precursor solution was patterned by UV radiation on the gel covered glass slide with a UV mask. The stiffness of the matrix was controlled by the concentration of macromer in the hydrogel precursor solution. Tumorsphere size and density, and expression of CSC markers were determined with incubation time in tumor CSC culture medium.

Results and Conclusion: The micro-patterned 3D synthetic hydrogel matrix with defined modulus supported tumorsphere formation and expression of CSC markers. Specifically, co-culture of MDA cells with hMSCs increased the expression of CD44 and ABCG2 markers of stemness by three-fold after 6 days of encapsulation in the engineered matrix from 25 to 58 for CD44 and 14 to 42 for ABCG2. Likewise, tumorsphere density more than doubled and average tumorsphere diameter increased from 25 to 47 µm after 6 days of incubation when MDA cells were co-encapsulated with hMSCs. The model inert matrix can be used to understand the effect of individual cell types in the tumor stroma on CSC maintenance and tumorigenesis.

Citation Format: Samaneh K. Sarvestani, Danial Barati, Esmaiel Jabbari. Maintenance of breast cancer stem cells in an inert matrix is mediated by mesenchymal stem cells in the tumor stroma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 169. doi:10.1158/1538-7445.AM2014-169
Abstract 1694: Combination of Indolizino[6,7-b]indole and Gefitinib synergistically suppresses the growth of EGFR-mutant NSCLC cells
Authors: Chen Chi-Wei , Tala Satishkumar , Su Tsann-Long , Lee Te-Chang
Published: May 2015

We have previously revealed that indolizino[6,7-b]indoles are effective antitumor agents against a variety of cancer cells. Indolizino[6,7-b]indoles were shown to induce DNA crosslinks and inhibit the enzymatic activities of topoisomerase I and II. Our recent results demonstrated that the derivatives of indolizino[6,7-b]indoles potently suppressed the cell growth of several non-small cell lung cancer (NSCLC) cells, including H460, PC9, PC9/gef B4, and H1975 cells in in vitro and in vivo systems. We also showed that BO-1978, one of indolizino[6,7-b]indole derivatives, completely suppressed the growth of CL1-5/GFP-Luciferase and PC9/gef B4-Luciferase cells in orthotopic lung cancer models. These results implicated that indolizino[6,7-b]indoles are potential candidate agents against NSCLC. EGFR mutations are frequently occurred in NSCLC. Although targeted agents such as Gefitinib is effectively suppression the growth of NSCLC with EGFR mutations, the resistance to Gefitinib is quickly developed and causes the failure of targeted treatments. Since the combination of targeted agents and cytotoxic drugs is one of strategies to overcome the problem encountered by targeted therapy, we further explore the therapeutic potential of combination of BO-1978 and Gefitinib against EGFR-mutant NSCLC. Our results showed that the combination treatment of PC9 and PC9/gef B4 cells with BO-1978 and Gefitinib resulted in synergistic induction of apoptosis and suppression of cell growth in cultured cells. We also confirmed the therapeutic efficacy of combined treatment of PC9 and PC9/gef B4 cells with BO-1978 and Gefitinib in xenografted tumor models. Since we did not observe severe body weight loss in mice received the combination treatment of BO-1978 and Gefitinib, our present studies apparently support that BO-1978 and its combination with Gefitinib is highly prospective as therapeutic agents against EGFR-mutant NSCLC.

Citation Format: Chi-Wei Chen, Satishkumar Tala, Tsann-Long Su, Te-Chang Lee. Combination of Indolizino[6,7-b]indole and Gefitinib synergistically suppresses the growth of EGFR-mutant NSCLC cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1694. doi:10.1158/1538-7445.AM2014-1694
Abstract 1705: Combinatorial therapeutics with targeting head and neck cancer initiating cells using active components from antrodia cinnamomea and conventional chemotherapy
Authors: Chang Ching-Wen , Lo Jeng-Fan
Published: May 2015

Background: Cancer initiating cells (CICs), also termed as Cancer stem cells (CSCs), represent a rare subpopulation of cells, which are responsible for tumor growth. CICs such as head and neck cancer initiating cells (HN-CICs), are often resistant to either radio- or chemotherapy. Therefore, development for drug candidates that target HN-CICs specifically will be effective for future oral cancer therapy.

Methods: In this study, we used the in vitro cell-based aldehyde dehydrogenase (ALDH) activity assay system, which has been demonstrated as a CICs marker, to screen for the active purified components from Antrodia Camphorata Mycelia extract (ACME), which can target HN-CICs. Next, the antitumorigenicity of combinatorial treatment with active components from ACME and conventional chemotherapy on HNSCC will be examined in vitro and in vivo.

Results: Herein, we first screened for the active components from natural products of ACM significantly down regulate the ALDH activity and CD44 positivity of Head and neck squamous cell carcinoma (HNSCC). Consequently, treatment of YMGKI-2 (analogue of ergosterol), a single and active compound purified from ACME, not only inhibited the ALDH activity but also reduced self-renewal property and expression of stemness genes (Oct-4 and Nanog) in enriched HN-CICs. Moreover, the repressive HN-CICs properties by YMGKI-2 treatment were caused by promoting cell differentiation. Additionally, treatment of YMGKI-2 results in down-regulation of Cox-2 and Src molecular mechanisms which both play important role in CICs. Further, the tumorigenic properties of HNSCC cells were attenuated by YMGKI-2 treatment in vivo. Lastly, combinatorial treatments with YMGKI-2 and standard chemotherapeutic drugs reveal synergistic effects on killing both HN-CICs and non-HN-CICs in vitro and in vivo.

Conclusion: Together, our results indicate that YMGKI-2 treatment significantly and selectively abolished the stemness properties and tumorigenicity of HN-CICs. These findings provide a new drug candidate from purified components of ACM as an alternative therapy in combination with conventional chemotherapy treatment modalities for head and neck cancer in the future.

Citation Format: Ching-Wen Chang, Jeng-Fan Lo. Combinatorial therapeutics with targeting head and neck cancer initiating cells using active components from antrodia cinnamomea and conventional chemotherapy. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1705. doi:10.1158/1538-7445.AM2014-1705
Abstract 1716: Targeting the insulin-like growth factor receptor/Insulin receptor and Src signaling network for the treatment of non-small cell lung cancer
Authors: Min Hye-Young , Yun Hye Jeong , Lee Hyo-Jong , Cho Jaebeom , Jang Hyun-Ji , Kim Kyung Min , Kim Woo-Young , Oh Seung-Hyun , Liu Diane , Lee J. Jack , Hong Waun K. , Wistuba Ignacio I. , Lee Ho-Young
Published: May 2015

Insulin-like growth factor I receptor (IGF-1R)-mediated signaling plays an important role in the proliferation, survival, and metastasis of cancer cells. The IGF-1R-targeting anticancer agents including monoclonal antibodies and small molecule tyrosine kinase inhibitors (TKIs) have been developed, but their antitumor effects have been marginal and limited in clinical trials. Therefore, the mechanism underlying resistance to the IGF-1R-targeting therapies and the rational combination strategies to overcome potential drug resistance need to be investigated. In this study, we demonstrated the association of Src with the resistance to the IGF-1R TKI in non-small cell lung cancer (NSCLC). We found the co-activation of IGF-1R/IR and Src in various human NSCLC cell lines, The mRNA expression and phosphorylation of IGF-1R and Src were also significantly correlated with each other in NSCLC databases from a public dataset and a tissue microarray (n=353). Next, we found Src can be activated through multiple pathways including EGFR and integrin β3 signaling and function as an alternative kinase for phosphorylation of IGF-1R, especially at Tyr1135/36, but not Tyr1131. Src is activated in lung cancer cells possessing both primary and acquired resistance to an IGF-1R TKI. Consistent with the results, inhibition of Src significantly attenuated activation of IGF-1R/IR and co-targeting of IGF-1R and Src effectively suppressed cell proliferation, colony formation, and tumor growth in vitro and in vivo. Taken together, these results suggest that Src causes resistance to IGF-1R TKIs by functioning as a key downstream modulator of multiple signaling pathways for IGF-1R phosphorylation and thus co-targeting IGF-1R and Src could be an effective therapeutic strategy for NSCLC.

Citation Format: Hye-Young Min, Hye Jeong Yun, Hyo-Jong Lee, Jaebeom Cho, Hyun-Ji Jang, Kyung Min Kim, Woo-Young Kim, Seung-Hyun Oh, Diane Liu, J. Jack Lee, Waun Ki Hong, Ignacio I. Wistuba, Ho-Young Lee. Targeting the insulin-like growth factor receptor/Insulin receptor and Src signaling network for the treatment of non-small cell lung cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1716. doi:10.1158/1538-7445.AM2014-1716
Abstract 172: Adipocytes decrease daunorubicin concentration in acute lymphoblastic leukemia cells
Authors: Sheng Xia , Tucci Jonathan , Behan James , Mittelman Steven D.
Published: May 2015

Obesity is associated with increased cancer incidence and mortality. Adipose tissue has been shown to play a role in several types of cancer, including acute lymphoblastic leukemia (ALL). We have demonstrated that murine ALL cells actively migrate into adipose tissue in mice, and that adipocytes protect ALL cells from daunorubicin (DNR) in vitro. We have further shown that media cultured by both adipocytes and ALL cells together (ALCM) can protect ALL cells from DNR. We hypothesize that adipocytes protect ALL cells from DNR by decreasing ALL cell intracellular drug accumulation.

Human pre B ALL cells (BV173) were co-cultured with 3T3-L1 adipocytes using a transwell system. Intracellular DNR was visualized using con-focal fluorescence microscopy at various time points in leukemia cells during DNR treatment. Drug uptake in leukemia cells treated with DNR and co-cultured with adipocytes was measured by flow cytometry. By preloading cells with DNR, drug efflux assays were also performed with ALL cells. Gene expression of ABCB1a and cell surface expression of MDR1 were quantified using qPCR and flow cytometry, respectively, in ALL cells co-cultured with adipocytes.

After 72 hours of DNR treatment, there were significantly more viable BV173 cells in the transwells placed over adipocytes than those over fibroblasts (290,000± 60,500 vs. 108,000± 13,000, p=0.008, n=4). Co-culture with adipocytes was associated with a lower intracellular DNR in BV173 cells. After 4 hours, DNR was 30% lower, and by 24 hours intracellular DNR was 80% less (n=1). However, co-culturing ALL cells with adipocytes was not associated with a significant increase in efflux rate of DNR from preloaded BV173 (half-life = 36±13 vs. 31±9 min., p=0.23, n=3). The mRNA expression of ABCB1a, the gene encoding MDR1, was increased in BV173 cells (130% increase, n=1) co-cultured with adipocytes for 24 hours. However, we did not detect an increase in surface MDR1 expression in BV713 co-cultured with adipocytes.

We then tested whether adipocyte-secreted factors would cause efflux of DNR from ALL cells. There was a tendency for DNR efflux rate to be higher in BV173 cells cultured in ALCM (half-life = 36±13 vs. 27±10 min., p=0.08, n=3). Further investigation is needed to confirm this effect.

These findings demonstrate that adipocytes may protect ALL cells from daunorubicin treatment in part by decreasing intracellular drug accumulation. However, it is not clear whether this effect is due to altered uptake, efflux, or intracellular drug action.

Citation Format: Xia Sheng, Jonathan Tucci, James Behan, Steven D. Mittelman. Adipocytes decrease daunorubicin concentration in acute lymphoblastic leukemia cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 172. doi:10.1158/1538-7445.AM2014-172
Abstract 1720: MSK1 mediates PI3K inhibition resistance by induction of β-catenin phosphorylation in glioblastoma
Authors: Wu Shaofang , Fu Jun , Zheng Siyuan , Verhaak Roel G. , Yung W. K , Koul Dimpy
Published: May 2015

Glioblastoma (GBM), the most common malignant brain tumor in adults, represents a compelling disease for kinase inhibitor therapy because majority of these tumors harbor genetic alterations that result in aberrant activation of growth factor signaling pathways. PI3K/mTOR-pathway is dysregulated in over 50% of human glioblastomas (GBM) and represents an attractive target for therapy. One major challenge for single pathway PI3K inhibition targeting therapy is intrinsic resistance. To study the mechanism of intrinsic resistance to PI3K inhibition, we analyzed the pre- and post-treatment reverse phase protein arrays (RPPA) data of both giloma cells and giloma initiating cells (GIC). Mitogen- and stress-activated protein kinase 1 (MSK1) was markedly induced after PI3K inhibitor treatment and it was linked with increase expression of β-catenin. We further found that MSK1 directly interacts with β-catenin and stabilizes β-catenin protein level. MSK1 also regulates β-catenin nuclear translocation and β-catenin transcriptional activity. More interestingly, using in vitro kinase assay, we identified MSK1 is a kinase that phosphorylates β-catenin. Finally, we showed that depletion of β-catenin potentiates PI3K inhibitors induced cytotoxity in a series of GICs. Taken together, our results suggest that MSK1/β-catenin signaling may serve as an escape survival signaling upon PI3K inhibition, and combination of PI3K inhibition and MSK1/β-catenin inhibition is required to induce lethal growth inhibition in human glioblastoma cells.

Citation Format: Shaofang Wu, Jun Fu, Siyuan Zheng, Roel G. Verhaak, W. K Yung, Dimpy Koul. MSK1 mediates PI3K inhibition resistance by induction of β-catenin phosphorylation in glioblastoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1720. doi:10.1158/1538-7445.AM2014-1720