bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 4648: Uncover novel drug combinations for triple negative breast cancer
Authors: Costa Carlotta , Dastur Anahita , Peterson Rachel , Leah Damon , Egan Regina , March Ryan , Benes Cyril , Engelman Jeffrey
Published: July 2016

Therapeutic options for triple negative breast cancers (TNBC) are limited to multiple lines of chemotherapy with no FDA-approved targeted therapies. In the absence of a clear driver oncogene, the most common molecular alterations, including EGF receptor and genes involved in cell cycle, DNA repair and the PI3K pathway, may represent new therapeutic opportunities in TNBC. Indeed clinical benefits from PARP, EGFR and PI3K inhibitors have been reported in some TNBC patient. However, none of these studies have demonstrated durable responses, indicating that inhibition of additional pathways might be necessary to successfully improve the clinical efficacy of targeted therapies in TNBC. To develop novel, combinatorial therapeutic approaches for TNBC we performed a pharmacological screen testing 672 unique drug combinations in multiple TNBC models. The screen identified previously known and efficacious synergies, such as between EGFR and PI3K inhibitors, supporting the validity of our data and analysis. Importantly, we also identified novel promising drug combinations that we are currently exploring.

Citation Format: Carlotta Costa, Anahita Dastur, Rachel Peterson, Damon Leah, Regina Egan, Ryan March, Cyril Benes, Jeffrey Engelman. Uncover novel drug combinations for triple negative breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4648.
Abstract 4654: A novel proteasome inhibitor, bis-Benzylidine Piperidone (RA190), control hepatocellular carcinoma effectively through inhibiting STAT3
Authors: Soong Rueyshyang
Published: July 2016

Hepatocellular carcinoma(HCC) is one of the most common malignancy, especially in the HBV endemic Asia area. However, there is still lack of effective chemotherapy drug to treat HCC, expect Sorafenib, tyrosine kinase inhibitor, the only FDA approved chemotherapy drug to treat HCC.

In this study, we explore the chemotherapeutic properties of a novel proteasome inhibitor, bis-Benzylidine Piperidone (RA190), and its ability to manipulate the tumor microenvironment. Unlike the marketed proteasome inhibitor Bortezomib, a chemotherapeutic drug used to treat relapsed multiple myeloma, which inhibits the 20S catalytic core of the 26S proteasome, RA190 irreversibly binds to the ubiquitin receptor RPN13/ADRM1 on the 19S regulatory cap of the 26S proteasome. RA190 inhibits proteasome function and triggers accumulation of polyubiquinated proteins, and has been shown to induce endoplasmic reticulum stress-related apoptosis in HepG2 and Hepa3B hepatoma cell lines. We also found RA190 We observed a significant apoptosis of cancer cells after treatment of RA190. These changes in cancer cell lines were caused by reduction of STAT3 activity. We also proved the treatment effect of RA190 in orthotropic HCC animal models. The initial study of this novel proteasome inhibitor demonstrates its potential as an effective HCC therapy.

Citation Format: Rueyshyang Soong. A novel proteasome inhibitor, bis-Benzylidine Piperidone (RA190), control hepatocellular carcinoma effectively through inhibiting STAT3. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4654.
Abstract 4655: Iron chelation inhibits mTORC1 signaling in tumor cells
Authors: Shang Chaowei , Zhou Hongyu , Huang Shile
Published: July 2016

Iron chelators are commonly used for treatment of iron overload diseases. Recent studies have shown that iron chelators possess potent anticancer activities. Iron chelators (ciclopirox and 3-AP) are in clinical trials for cancer treatment. However, the molecular mechanism underlying the anticancer effect of iron chelation is not well understood. Mammalian/mechanistic target of rapamycin (mTOR) is a master kinase, regulating cell growth/proliferation and survival through sensing environmental cues. mTOR functions as at least two complexes (mTORC1/2). Here we show that two iron chelators, ciclopirox olamine (CPX) and Dp44mT, inhibit tumor cell proliferation by suppressing mTORC1 signaling in human rhabdomyosarcoma (Rh30) and lung cancer (A549 and A427) cells. This is evidenced by the findings that treatment with CPX or Dp44mT inhibited the phosphorylation of 4E-BP1 and S6K1, two best known effector molecules of mTORC1, which could be blocked by addition of ferrous sulfate. Addition of ferrous sulfate prevented the growth inhibitory effect of CPX. Ectopic expression of constitutively active mTOR also conferred resistance to CPX-induced growth inhibition. Mechanistically, iron chelation inhibition of mTORC1 was partially linked to the activation of AMPK, a negative regulator of mTORC1. Overexpression of a dominant-negative AMPK (DN-AMPK) in Rh30 cells attenuated the inhibitory effect of CPX or Dp44mT on the phosphorylation of S6K1 and 4E-BP1. In addition, iron chelation also transiently stabilized HIF-1α and further upregulated the expression of its downstream effector Bnip3, another negative regulator of mTORC1. Knockdown of Bnip3 partially attenuated the inhibitory effect of iron chelation on mTORC1. Furthermore, we found that iron chelation increased the translocation of mTOR from the cytoplasm to the nucleus. The co-localization of mTOR with the third negative regulator of mTOR, PML (promyelocytic leukemia), increased in the nucleus upon iron chelation. Moreover, iron chelation did not obviously alter the phosphorylation of IGF-1 receptor, PI3K or PTEN. The effect of iron chelation on mTORC2-mediated phosphorylation of Akt was cell line dependent. Taken together, the results suggest that the anticancer effect of iron chelation is in part related to inhibition of mTORC1 signaling, and iron chelation inhibits mTORC1 signaling via multiple mechanisms. (Supported by the FWCC, LSU Health Sciences Center)

Citation Format: Chaowei Shang, Hongyu Zhou, Shile Huang. Iron chelation inhibits mTORC1 signaling in tumor cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4655.
Abstract 4659: Folic acid-metabolizing enzymes regulate 5-fluorouracil anticancer activity on colorectal cancer cell lines
Authors: Tsukihara Hiroshi , Tsunekuni Kenta , Takechi Teiji
Published: July 2016

Background: In colorectal cancer chemotherapy, the current standard of care includes 5-fluorouracil (5-FU) and leucovorin (LV) combination therapy. To understand the role of folic acid-metabolizing enzymes in the LV-mediated enhancement of 5-FU's antitumor activity, we suppressed the expression of genes related to folic acid metabolism and evaluated the resultant effect on the proliferation inhibitory effect of 5-fluoro-2′-deoxyuridine (FdUrd). Method: We downregulated the expression of thymidylate synthase (TS), folate receptor 1 (FOLR1), methylenetetrahydrofolate reductase (MTHFR), methylenetetrahydrofolate dehydrogenase (MTHFD), dihydrofolate reductase (DHFR), and phosphoribosylglycinamide formyltransferase (GART) by lipofection of small interfering RNA (siRNA) in DLD-1 and HCT116 cells, and calculated the relative change in IC50 values on 48 hr exposure to FdUrd in comparison with the corresponding IC50 values in control siRNA-treated cells. In cells with TS downregulation, LV-mediated enhancement of sensitivity to FdUrd was also evaluated. Sensitivity to FdUrd was determined using the crystal violet staining method. Results: Treatment with siRNA downregulated the expression of folic acid-metabolizing enzymes. LV enhanced the sensitivity to FdUrd in control siRNA-treated cells in a dose-dependent manner. However, in cells with TS downregulation, LV did not enhance the sensitivity to FdUrd. Downregulation of folic acid-metabolizing enzymes, except TS, decreased the efficacy of FdUrd, although there was little decrease in FdUrd efficacy owing to MTHFR downregulation. Conclusion: The level of TS expression determined the LV requirement, and downregulation of folic acid-metabolizing enzymes, which impaired the folic acid cycle, decreased the efficacy of 5-FU. Comparison of the IC50 values in target siRNA-treated cells and control siRNA-treated cells.DLD-1 cellsHCT116 cellsexpression (%)*IC50 (μM)fold changeexpression (%)*IC50 (μM)fold changeNon-silencing Control siRNA100.000.671.00100.000.251.00TS10.580.010.0114.840.030.12FOLR19.148.6512.9125.122.5910.36MTHFR25.441.432.1348.750.883.52MTHFD9.662.734.0715.061.997.96DHFR8.524.146.1817.231.706.80GART18.905.388.037.102.469.84Values are means (n = 3). *: Expression (%) is the expression at the beginning of FdUrd treatment (at 48 hr after siRNA treatment).

Citation Format: Hiroshi Tsukihara, Kenta Tsunekuni, Teiji Takechi. Folic acid-metabolizing enzymes regulate 5-fluorouracil anticancer activity on colorectal cancer cell lines. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4659.
Abstract 4675: Synergistic effect of pacritinib with erlotinib on JAK2-mediated resistance in epidermal growth factor receptor mutation-positive non-small cell lung cancer
Authors: Ochi Nobuaki , Isozaki Hideko , Takeyama Masami , Singer Jack W. , Yamane Hiromichi , Honda Yoshihiro , Kiura Katsuyuki , Takigawa Nagio
Published: July 2016

Patients with non-small cell lung cancer (NSCLC) harboring activating mutations in the epidermal growth factor receptor (EGFR) benefit from treatment with EGFR tyrosine kinase inhibitors (TKIs). However, almost all of the patients eventually develop resistance to EGFR-TKIs within approximately one year. The resistance mechanisms of EGFR-TKIs have not been fully elucidated. We previously established an erlotinib-resistant NSCLC cell line named PC-9/ER3 after continuously exposing PC-9 cells, which harbor an in-frame deletion in EGFR exon 19, to erlotinib. PC-9/ER3 cells were 136-fold more resistant to erlotinib than the parental cells. Although the PC-9/ER3 cells did not carry the T790M mutation or MET amplification and had similar levels of pSTAT3, pJAK2 increased in the resistant cells (Cancer Sci 103, 1795-802; 2012). Meanwhile, pacritinib is a novel macrocyclic pyrimidine-based JAK2/FLT3 inhibitor with clinical activity in patients with myelofibrosis and lymphoma, which will be used as a standard therapy for myelofibrosis. In this study, we evaluated the synergistic effect of pacritinib combined with erlotinib on JAK2-medatited EGFR-TKI resistant NSCLC.

Drug sensitivity was determined using an MTT assay and the combination index was calculated according to the methods based on the median-effect analysis. The combination of pacritinib with erlotinib showed synergistic effects on JAK2-medated EGFR TKI-resistant PC-9/ER3 cells in some cases. Western blotting showed that the combination treatment markedly suppressed pAKT and pERK although pSTAT3 was equivalent regardless of treatment with the pacritinib, erlotinib, pacritinib plus erlotinib, or control in PC-9/ER3 cells. Receptor tyrosine kinase array profiling demonstrated that pacritinib suppressed MET in the PC-9/ER3 cells. The combined treatment of pacritinib and erlotinib in PC-9/ER3 xenografts showed more tumor shrinkage compared with each drug as monotherapy. Western blotting revealed that pMET in the tumor samples was inhibited. These results suggest MET suppression by pacritinib may play a role in overcoming the EGFR-TKI resistance mediated by JAK2 in the PC-9/ER3 cells.

In conclusion, pacritinib combined with EGFR-TKI might be a potent strategy against JAK2-mediated EGFR-TKI resistance.

Citation Format: Nobuaki Ochi, Hideko Isozaki, Masami Takeyama, Jack W. Singer, Hiromichi Yamane, Yoshihiro Honda, Katsuyuki Kiura, Nagio Takigawa. Synergistic effect of pacritinib with erlotinib on JAK2-mediated resistance in epidermal growth factor receptor mutation-positive non-small cell lung cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4675.
Abstract 4686: Intermittent exposure to EGFR tyrosine kinase inhibitors selects less EGFR T790M mutant clones than continuous exposure in lung cancer cell lines
Authors: Lee Youngjoo , Kim Kyoung-Yeon
Published: July 2016

Background: Drug-resistant cell lines are essential tools for investigating the mechanisms of resistance to molecular-targeted anti-cancer drugs. However, little is known about how to establish clinically relevant drug-resistant cell lines. Our study examined the impact of a drug-free period on the establishment of a cell line with clinically relevant resistance to molecular-targeted drugs.

Methods: We used PC-9 cells, a lung cancer cell line carrying EGFR mutation, because this is a validated target for EGFR tyrosine kinase inhibitors (TKI). PC-9 cells were intermittently or continuously exposed to increasing concentrations of gefitinib (0.01 μM to 1.0 μM) and the emergence of the most common acquired resistance mutation in EGFR, T790M, was determined.

Results: T790M was detected at a 25-fold lower drug concentration in cells continuously exposed to gefitinib (PC-9/GRc) than in cells intermittently exposed to gefitinib (PC-9/GRi) (0.04 μM vs 1.0 μM, respectively). The mutation frequencies at those drug concentrations were 19.8% and 8.0% in PC-9/GRc and PC-9/GRi cells, respectively. After drug-free culture for 8 weeks, resistance to gefitinib decreased in the PC-9/GRi cells but not in the PC-9/GRc cells. In the PC-9/GRc cells, the frequency of the T790M mutation was consistently about 20% from 0.04 μM to 1.0 μM of gefitinib. In the PC-9/GRc cells, the T790M mutation was detected in all single-cell clones, at frequencies ranging from 7.0% to 37.0%, with a median of 19.5% (95% confidence interval, 17.3%-20.9%).

Conclusion: Intermittent exposure to EGFR-TKIs reduces the emergence of the EGFR T790M mutation in a lung cancer cell line.

Citation Format: Youngjoo Lee, Kyoung-Yeon Kim. Intermittent exposure to EGFR tyrosine kinase inhibitors selects less EGFR T790M mutant clones than continuous exposure in lung cancer cell lines. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4686.
Abstract 4698: BET protein inhibitors prevent TKI-induced drug resistance in solid tumors
Authors: Zhao Yuan , Wu Yiyuan , Wang Hexiang , Ren Bo , Liu Ye , Wei Min , Zhou Changyou , Luo Lusong
Published: July 2016

Acquired drug resistance is one of the major challenges for clinical application of tyrosine kinase inhibitor (TKI) in cancer treatment. TKI-induced drug resistance could develop as a result of adaptive cell reprogramming that leads to pathway feedback activation in the same signaling pathway or parallel pathways or gatekeeper mutations abolishing drug binding. The findings of reversible drug response and lack of genetic mutations in TKI-resistant tumor cells suggest epigenetic basis during resistance development process. Targeting epigenetic modifiers and readers, in particular, the bromodomain and extra-terminal (BET) protein family, has shown promising efficacies against both primary and drug-resistant hematological malignancies via modulating transcription profile and suppressing the MYC oncogene. BGB-3619 is a novel, potent inhibitor of BET family proteins (BRD2, BRD3, BRD4 and BRDT) with IC50 ranging from 20 to 49 nM. It demonstrates superior anti-proliferation activity than iBET762 in multiple leukemia and lymphoma cell lines. In this study, we investigated the effect of BGB-3619 and iBET762 on solid tumor cells during and after TKI-resistance development. From cell killing assays, BET inhibitors were found to be much more potent to TKI-resistant cells (vemurafenib-resistant A375, HT29, SK-MEL-5, cells and erlotinib-resistant HCC827 cells) than their parental cells. Notably, long-term colony formation assays showed that combination of low dose BET inhibitors and TKI effectively suppressed the expansion of TKI-tolerated cell populations. The enhanced sensitivity of TKI-resistant cells to BET inhibitor was due to strong G1 phase arrest rather than induction of apoptosis. Furthermore, BET inhibitors blocked cell proliferation independent of c-Myc inhibition, suggesting they might affect a broad transcription network and provide favorable epigenetic state to induce cell cycle arrest. Taken together, these findings suggested potential therapeutic activity of BET inhibitor in TKI-resistant solid tumors and a strategy of combining BET inhibitors with TKIs to overcome resistance to targeted cancer therapies.

Citation Format: Yuan Zhao, Yiyuan Wu, Hexiang Wang, Bo Ren, Ye Liu, Min Wei, Changyou Zhou, Lusong Luo. BET protein inhibitors prevent TKI-induced drug resistance in solid tumors. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4698.
Abstract 4734: Inhibitory effects of metformin on epithelial-mesenchymal transition of CD44+/CD117+ ovarian cancer stem cells
Authors: Xiao Gary G. , Zhang Rongrong , Zhang Ping , Wang Hong , Hou Dongming , Li Wentao , Li Chenwei
Published: July 2016

Background: Although metformin, a first-line drug for treating diabetes, may play an important role in inhibition of epithelial ovarian cancer cell growth and cancer stem cells (CSCs), metformin at low dose showed less effect on proliferation of ovarian cancer cells. In this study, we evaluated the effect of metformin at low dose on ovarian CSCs in order to understand the molecular mechanisms underlying ovarian tumorigenesis.

Methods: The inhibitory effects of metformin at los dose on proliferation and population of ovarian cancer cells including SKOV3 and A2780 were assessed by cell proliferation assay and flow cytometry. Quantitative real-time PCR assays on expression of Bcl-2, Survivin and Bax were performed to determine the effect of the metformin at low dose on epithelial-mesenchymal transition (EMT) of cancer cells and CSCs. Tumor sphere formation assay was also performed to evaluate the effect of metformin on spheres forming ability of CSCs. The therapeutic efficacy and the anti-CSC effects of metformin at low dose were investigated by using both SKOV3 cells and primary tumor xenografts. In addition, the CSC frequency and EMT in tumor xenograft models were also assessed by flow cytometry and quantitative real-time PCR.

Results: Metformin at low dose did not affect proliferation of ovarian cancer cells, however, it inhibited the population of the CD44+/CD117+ selectively, neither CD133+ nor ALDH+ cells. It suppressed expression of snail2, twist and vimentin significantly in cancer cells and CD44+/CD117+ CSCs in vitro. Low dose of metformin reduced survivin expression in CSCs leading to arrest of cell cycle. Metformin at low concentration inhibited the secondary and the tertiary tumor sphere formation, decreased the growth of either SKOV3 or primary ovarian tumor xenograft, enhanced the anticancer effect of the cisplatin, and lowered the proportion of the CD44+/CD117+ CSCs in the xenograft tissue. Metformin was also associated with a reduction of snail2, twist, and vimentin in CD44+/CD117+ ovarian CSCs in vivo.

Conclusions: Our results implicate that metformin at low dose inhibits selectively CD44+/CD117+ ovarian CSCs through inhibition of EMT and potentiates the effect of the cisplatin.

Citation Format: Gary G. Xiao, Rongrong Zhang, Ping Zhang, Hong Wang, Dongming Hou, Wentao Li, Chenwei Li. Inhibitory effects of metformin on epithelial-mesenchymal transition of CD44+/CD117+ ovarian cancer stem cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4734.
Abstract 4735: Designing novel warheads for targeted therapies: SAR and efficient strategies for the synthesis of analogues of tubulysin
Authors: Vlahov Iontcho , You Fei , Kleindl Paul , Vetzel Marilynn , Reddy Joseph , Leamon Christopher
Published: July 2016

Background: Tubulysins are natural products isolated from myxobacterial species. They are potent mitotic poisons as they inhibit the polymerization of tubulin into microtubules. Structurally, tubulysins are linear tetrapeptides comprised of N-Me pipecolic acid (Mep), isoleucine (Ile), tubuvaline (Tuv) and tubutyrosine (Tut). All natural tubulysins possess an acid-, base-, and enzyme-sensitive N-acyloxymethyl substituent, as well as a labile acetate group. For the natural tubulysins, both of these functional groups are essential for their potent cytotoxicity. The focus of this presentation is on design and synthesis of chemically stable analogs of tubulysin with improved biological activity.

Methods: To explore the influence of tubulysin's functional groups on its cytotoxicity, we designed novel analogs, incorporating ether, thioether, amide and carbamate-based side chains. We also suggested basic SAR-rules for the activity of these synthetic analogs.

Results: Structural features, critical for the tubulysin's cytotoxicity, were investigated. e.g., changing the (R)-OAc group of Tuv to (S)-NHAc completely abolished cytotoxicity, while analogs possessing (R)-NHAc on the Tuv moiety still exhibited activity. On the other hand, exchange of Tuv's (R)-OAc group with (R)-OMe had no influence activity. Replacement of the O-acyl part of N-acyloxymethyl substituent (dotted circle) with an alkyl or alkylthiol group resulted in N,O-acetals or N,S-thioacetals possessing similar or higher activity. Tup and Tut are interchangeable in terms of the activities of their respective tubulysin analogs.

Conclusion: We designed and synthesized tubulysin analogs which are less prone to degradation under acidic and basic conditions, as well as enzymic influences. Structural features, essential for the cytotoxicity of the tubulysin analogs, were established. Some of the new compounds, especially those with N,S-thioacetal side chains, have increased cytotoxicity in comparison to natural tubulysins. These novel tubulysin analogs were used as warheads for folate receptor(FR)-targeted therapy.

Citation Format: Iontcho Vlahov, Fei You, Paul Kleindl, Marilynn Vetzel, Joseph Reddy, Christopher Leamon. Designing novel warheads for targeted therapies: SAR and efficient strategies for the synthesis of analogues of tubulysin. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4735.
Abstract 4736: PDE10A overexpression in cancer cells and tumors as compared to normal cells and tissues
Authors: Lindsey Ashley S. , Lee Kevin , Zhu Bing , Arora Ritu , Otali Dennis , Ramirez-Alacantara Veronica , Grizzle William , Piazza Gary
Published: July 2016

Phosphodiesterase 10A (PDE10A) is a cGMP and cAMP degrading PDE isozyme that is expressed in areas of the brain related to motor function and cognition. An elevation in neural PDE10A expression has been strongly linked to many diseases that affect cognition, including schizophrenia and Huntington's disease. Recently, high levels of PDE10A were shown to be expressed in colon tumor cells in vitro and in vivo compared with cells derived from normal colon and normal colonic mucosa (Li et al., Oncogene 2015). PDE10A inhibition by small molecules or genetic silencing, attenuated tumor cell growth by a mechanism involving cGMP/PKG activation, the suppression of β-catenin and a decrease in TCF transcriptional activity (Li et al., Oncogene 2015). These observations suggest that PDE10A may play an important role in tumorigenesis and PDE10A could serve as a novel therapeutic target for colorectal cancer. However, the expression and role of PDE10A in other cancer cell types has yet to be elucidated. Here we report that PDE10A expression is elevated (compared to controls) in tumor cells and solid tumors from xenograft, as well as, genetic models from the colon, breast, and lung using western blot and immunohistochemistry. The human colon adenocarcinoma cell line, HT29, the human breast adenocarcinoma cell line, MDA-MB-231, and the human lung carcinoma cell line, A549, showed elevated expression of PDE10A as compared to the normal colon mucosal epithelial cell line, NCM460, normal human mammary epithelial cells, and normal human airway epithelial cells, respectively. Solid tumors collected from the colons of heterozygous APCmin mice displayed an elevation in PDE10A levels as compared to uninvolved mucosa from the APCmin mice and wild type colon mucosa. Solid tumors collected from the mammary glands of viral transgenic FVB-MMTV-Her2 mice also possessed high levels of PDE10A as compared to FVB wild type mice. These findings suggest that PDE10A could be a novel therapeutic target for not only colorectal cancer, but breast and lung cancers as well.

Citation Format: Ashley S. Lindsey, Kevin Lee, Bing Zhu, Ritu Arora, Dennis Otali, Veronica Ramirez-Alacantara, William Grizzle, Gary Piazza. PDE10A overexpression in cancer cells and tumors as compared to normal cells and tissues. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4736.
Abstract 475: NTF2 regulates nuclear size in mammalian cells and may contribute to altered nuclear size in melanoma
Authors: Vukovic Lidija D. , Stohr Bradley A. , Levy Dan L.
Published: July 2016

Nuclear size and morphology are distinct cancer features that pathologists use for diagnostic purposes. Proteins that regulate nuclear size have been identified in Xenopus, where nuclear import rates correlate with nuclear size. The levels of two nuclear import factors, importin α and NTF2, were shown to be particularly important in nuclear size regulation. It has also been shown that importin α2 is a potential biomarker in non-small cell lung cancer, as well as importin α1 in breast cancer. Our data implicate that NTF2 is a possible cancer biomarker.

Our main goal is to analyze how these nuclear scaling factors affect nuclear size during carcinogenesis and to test how nuclear size impacts cancer growth characteristics. We find that manipulating the levels of importin α2 and NTF2 in HeLa and MRC-5 cells leads to altered nuclear size, demonstrating a conserved function for these factors in nuclear size regulation. To place these results in a cancer context, we are focusing on melanoma cell lines, including radial and vertical growth primary melanomas and metastatic melanomas. We find that, compared to normal melanocytes, the nuclear-to-cytoplasmic (N/C) volume ratio is increased in the cancer cell lines. Western blot analysis revealed an inverse correlation between NTF2 protein levels and nuclear size. We confirmed these results using a melanoma tissue microarray, finding similar differences in nuclear size and NTF2 expression levels between benign nevi and melanomas.

We next performed transient transfection experiments with our melanoma cell lines. Importin α2 knock down led to smaller nuclear size, while knocking down the levels of NTF2 increased nuclear size, consistent with our Xenopus results. We also observed reduced nuclear size when NTF2 was ectopically expressed. Currently we are generating stable, inducible melanoma cell lines where we can precisely alter NTF2 and importin α expression levels using doxycycline. We will use these inducible cell lines to examine how altering nuclear size impacts cell proliferation rates, invasiveness, and apoptosis. We will also investigate how nuclear size affects gene positioning using FISH, focusing on genes involved in melanoma formation and metastasis. In the long term, we plan to move these studies into a mouse model where we can test how nuclear size affects in vivo metastatic capacity.

Citation Format: Lidija D. Vukovic, Bradley A. Stohr, Dan L. Levy. NTF2 regulates nuclear size in mammalian cells and may contribute to altered nuclear size in melanoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 475.
Abstract 4750: Characterization of the cytoskeletal protein MACF1 in lung cancer
Authors: Afghani Najlaa , Quick Quincy A.
Published: July 2016

Genetic variation between cancer patients with the same tumor and intratumor genetic heterogeneity have broadened the complexity of factors that contribute to clinical therapeutic resistance and poor response outcomes. This has made it imperative to identity atypical expressed outliers that influence the maintenance and progression of cancers. We have identified and investigated the spectraplakin protein, Microtubule Actin Cross-Linking Factor 1 (MACF1) which functions as an actin-microfilament and microtubule crosslinker for its role in lung cancers. Genomic data generated by the Cancer Genome Atlas (TCGA) and the International Cancer Genome Consortium (ICGC) indicate that the MACF1 gene is mutated and/or amplified in ∼15% of squamous lung cancers and 25% of lung cancers, respectively. Further examination with immunohistochemistry expression analysis revealed that MACF1 is highly expressed in several lung cancer subtypes, particularly adenocarcinomas and squamous cell carcinomas, as compared to normal lung tissue. Additionally, functional studies showed that suppression of MACF1 with RNA interference significantly impaired the reproductive capacity of these solid tumors. Taken together, MACF1 represents a unique target with genetic alterations and diagnostic biomarker potential in lung cancers, the leading cause of cancer deaths in the United States.

Citation Format: Najlaa Afghani, Quincy A. Quick. Characterization of the cytoskeletal protein MACF1 in lung cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4750.
Abstract 4758: Benzaldehyde suppresses multiple signal pathways in cancer cells by regulating 14-3-3ζ-mediated protein-protein interactions
Authors: Saitoh Jun , Saya Hideyuki
Published: July 2016

Benzaldehyde is the simplest aromatic aldehyde constituent of almonds and many fruits. Anticancer effect of Benzaldehyde was first reported in 1980, and multi-institutional clinical trials were performed in those days in Japan. However trial was over without determination of effectiveness, only its safety was confirmed. The underlying mechanism why Benzaldehyde specifically suppresses growth of some particular cancer cells but not that of normal cells has not been elucidated. Therefore, we attempted to clarify the mechanism of anticancer effect of Benzaldehyde. In pancreatic cancer cell BxPC3 and in non-small cell lung cancer cell A549, we found that Benzaldehyde inhibits PI3K/AKT/mTOR, STAT3, NFκB and ERK pathways, those are major signaling pathways activated in cancer cells. Effects of Benzaldehyde on multiple signaling pathways are found to be derived from regulation of 14-3-3 family proteins which interact with phosphorylation sites of various proteins of multiple signals. In BxPC3 cells, Benzaldehyde treatment reduced the phosphorylation levels of 14-3-3-binding sites. Furthermore, we ectopically expressed seven isoforms of 14-3-3 in HEK293T cells and found that Benzaldehyde treatment significantly suppressed association of 14-3-3ζ with client proteins such as mTOR, Rictor, cRaf, STAT3 and FOXOs. The interaction of other isoforms of 14-3-3 with their client proteins was also partially reduced. But, the expression levels of those seven 14-3-3 isoforms were not significantly changed. Those data indicate that Benzaldehyde suppresses the interaction of 14-3-3ζ with its client proteins. Recent reports have shown that 14-3-3ζ is overexpressed in many cancers and acts as a signaling hub controlling the network of oncogenic pathways, suggesting that 14-3-3ζ associates with carcinogenesis, metastasis and resistance for chemotherapy and radiation. Hence, Benzaldehyde is considered to be a new class of anti-cancer agent inhibiting 14-3-3ζ-mediated tumor promoting and/or maintaining signals.

Citation Format: Jun Saitoh, Hideyuki Saya. Benzaldehyde suppresses multiple signal pathways in cancer cells by regulating 14-3-3ζ-mediated protein-protein interactions. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4758.
Abstract 4762: Gremlin 2 is repressed in invasive endometrial cancer and inhibits cell growth in vitro
Authors: Tsubamoto Hiroshi , Inoue Kayo , Sakata Kazuko , Shibahara Hiroaki , Miyoshi Yasuo
Published: July 2016

Background: There are limited therapeutic opportunities for the treatment of advanced or metastatic endometrial cancer (EC), and limited diagnostic tools of myometrial invasion for fertility sparing management of early stage EC. Novel approach based on molecular profiling of EC cells are required. Patients and Methods: We used microarray analysis of EC tumour samples in order to identify tumour-specific changes in gene expression. Identified the most frequently and lowest repressed gene was subjected to immunohistochemistry of tissues of EC. MTT assay and migration assay using EC cells were also conducted to evaluate the antitumor activity of the identified gene. Results: The most significantly suppressed gene in EC compared with the control was Gremlin 2 with an 8.5-fold reduction (p<0.001). Immunohistochemistry revealed that Gremlin 2 was expressed in 4 of 4 tissues of normal endometrium, in 4 of 4 tissues of atypical endometrial hyperplasia and 5 of 5 tissues of low grade EC with FIGO stage IA without myometrial invasion. Among 13 patients with low-grade FIGO stage I with myometrial invasion, Gremlin 2 was partially expressed in the myometrial invasion front in 11 (85%) patients. The MTT assay revealed the proliferation of Ishikawa cells incubated with 1.0 ìg/ml and 5.0 ìg/ml of Gremlin 2 and HEC-1A cells incubated with 5.0 ìg/ml of Gremlin 2 were significantly reduced (P = 0.029, P = 0.025, and P = 0.048, respectively). The proliferation of Ishikawa cells was significantly attenuated after incubation with Gremlin 2 for 72 h (P = 0.024). On the other hand, the migration assay did not show influence of Gremlin 2 on Ishikawa or HEC-1A cells. Conclusion: Gremlin 2, formerly known as protein related to Dan and cerberus (PRDC), has been implicated in development of the embryo and the ovarian follicle in animals, however, there is no report of Gremlin 2 in association with neoplasm or cancer. Gremlin 2 downregulation may lead to carcinogenesis and progression of EC. We suggest that re-activation of Gremlin 2-associated pathways could suppress EC progression, and should thus be explored as a potential novel therapeutic approach as well as diagnostic tool of myometrial invasion.

Citation Format: Hiroshi Tsubamoto, Kayo Inoue, Kazuko Sakata, Hiroaki Shibahara, Yasuo Miyoshi. Gremlin 2 is repressed in invasive endometrial cancer and inhibits cell growth in vitro. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4762.
Abstract 4773: Gene-targeted apoptosis as a novel therapeutic strategy for HER2-positive breast cancer
Authors: Rogers Faye A. , Kaushik Meetu
Published: July 2016

The ability to target HER2-driven breast cancers using anticancer agents with mechanisms of actions that are independent of the HER2 cellular growth function, represents a powerful new tool to circumvent drug resistance experienced with traditional HER2-targeted therapies. We have discovered that manipulation of the balance between the DNA repair response and apoptotic pathways provides an alternative strategy to induce targeted apoptosis in HER2-amplified breast cancers. Our recent finding that triplex-induced DNA damage can activate apoptosis in human cells has yielded the opportunity to develop a new class of HER2-targeted therapies. Here, we have uncovered the novel finding that triplex-induced apoptosis only occurs when multiple triplex structures are formed, while NER (nucleotide excision repair)-dependent repair prevails in the presence of one or two structures. With this in mind, we have designed sequence-specific DNA-binding molecules that create chromosomal triplex structures and activate tumor-specific apoptosis through the induction of excessive DNA damage at the HER2 locus. Importantly, this only occurs in malignant cells with multiple copies of the HER2 gene. We have evaluated the efficacy of the HER2-targeted triplex-forming molecules using cell growth and apoptosis assays and demonstrate that these molecules are particularly effective in eliciting tumor specific apoptosis in HER2-amplified breast cancer cell lines. Furthermore, these molecules have the ability to suppress the growth and metastasis of human HER2-positive breast cancers in a xenograft mouse model. Moreover, we demonstrate that the NER protein, XPD mediates the survival-death decision in response to triplex-induced DNA damage via a p53-independent mechanism that involves phosphorylation of the H2AX tyrosine 142 residue, which stimulates the signaling pathway to recruit pro-apoptotic factors to the damage site. Our results establish an alternative and novel method to specifically target HER2-positive breast cancers by exploiting the cell's own DNA damage response machinery. This study introduces a new paradigm for gene-targeted drugs that can be used in the treatment of HER2-positive and drug-resistant breast cancers with minimal potential for toxicity to normal tissue.

Citation Format: Faye A. Rogers, Meetu Kaushik. Gene-targeted apoptosis as a novel therapeutic strategy for HER2-positive breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4773.
Abstract 4804: Polygodial: A potential sesquiterpene dialdehyde for castration-resistant prostate cancer treatment
Authors: Pillai Akshita P. , Dasari Subramanyam , Patel Bhavani , Banerjee Souresh , Kornienko Alexander V. , Munirathinam Gnanasekar
Published: July 2016

Major cause for prostate cancer mortality is due to the development of castration-resistant prostate cancer (CRPC) which usually develops when prostate cancer patients undergo standard androgen deprivation therapy. Treatment options currently available for CRPC are not very efficient and have many side effects. Hence, there is an urgent need to identify effective treatment strategies for CRPC. Natural compounds have previously shown to be an effective alternative treatment strategy for cancer. Polygodial (PG) an active constituent of mountain pepper belonging to sesquiterpene dialdehyde family has shown to have several pharmacological benefits including anti-bacterial, anti-fungal, anti-inflammatory, and anti-cancer properties. The objective of this study is to determine the therapeutic effects of PG against CRPC in a pre-clinical study. Cell lines used in this study were androgen dependent LNCaP and CRPC C4-2, DU145, and PC-3 cells. MTT, soft agar, and wound healing assays were performed to evaluate the effects of PG respectively on cell survival, anchorage independent growth, and migration characteristics of prostate cancer cells. PC-3 cells were utilized to determine the anti-cancer mechanisms of PG. Cell viability assay results showed PG effectively inhibited cell proliferation of CRPC C4-2, DU145 and PC-3 cell lines as compared to androgen dependent LNCaP cells. PG treatment significantly reduced the colony growth of CRPC cells in soft agar plates as compared to controls which correlates with its inhibitory effect on anchorage independent growth of these cells. In addition, PG also reduced the migration potential of CRPC cells in a wound healing assay. Inhibition of anchorage independent growth and motility of PCa cells by PG suggests its tumor suppressive and anti-metastatic potential. Western blot analysis showed that PG treatment downregulated the expression of a key cell survival molecule, High mobility group box1 (HMGB1) while promoting PARP-1 cleavage in PC-3 cells. Interestingly, our results also showed that BiP/GRP78, a marker of endoplasmic reticulum (ER) stress was upregulated following PG treatment in PC-3 cells. These findings suggest that PG enforces its tumor suppressive action by inhibiting HMGB1 signaling axis with concurrent activation of ER stress pathway in CRPC cells. Taken together, our study shows that PG might be an effective chemotherapeutic natural compound especially for CRPC.

Citation Format: Akshita P. Pillai, Subramanyam Dasari, Bhavani Patel, Souresh Banerjee, Alexander V. Kornienko, Gnanasekar Munirathinam. Polygodial: A potential sesquiterpene dialdehyde for castration-resistant prostate cancer treatment. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4804.
Abstract 4808: Identification of a novel compound, MO2455, that induces poly(ADP-ribose) (PAR) accumulation and inhibits the growth of cancer cells in vitro and in vivo
Authors: Shimoyama Tatsu , Sawada Takeshi , Akimoto Mari , Sasaki Yuka , Fujimori Hiroaki , Ishikawa Yoshinobu , Okawara Tadashi , Irie Tetsumi , Takamura Takeji , Matsuno Kenji , Inoue Kengo , Masutani Mitsuko , Koizumi Fumiaki
Published: July 2016

Poly (ADP-ribose) chain (PAR) formed by poly (ADP-ribose) polymerase (PARP) is catabolized mainly by poly (ADP-ribose) glycohydrolase (PARG). PARG is emerging as a therapeutic target for cancer, because its inhibition leads to cell death in some kinds of cancer cell lines.

In order to obtain small molecules that effectively inhibit PARG protein, an in-house collection of ∼10,000 small molecules were screened for their ability to accumulate the PAR in A549 cells at 5 μM. We identified ∼100 hit compounds. Among them, MO2282 and MO2455 induced the most significant accumulation of PAR. MO2455 is an analogue of MO2282 with improved water-solubility. MO2282 and MO2455 were evaluated in vitro for their ability to inhibit the catalytic activity of PARG. MO2282 and MO2455 showed modest inhibition activities against recombinant rat PARG. They also inhibited the growth of various kinds of cancel cell lines in vitro at an IC50 value of 0.05 - 3.0 μM and showed different spectrum of antitumor activity from conventional anticancer drugs, CDDP, ADM, PTX, and CPT-11. Next, we investigated the growth-inhibitory effect of MO2455 on A549 cells in a xenotransplanted model. A significant anti-tumor activity was observed in mice when treated with MO2455 at doses of 25 mg/kg every two days. Although treatment-related body weight loss was observed in mice treated with MO2455, body weight recovered by day 8.

In conclusion, the present data suggest that MO2455 has potential as a cancer drug with different mechanisms of action from conventional anti-cancer drugs.

Citation Format: Tatsu Shimoyama, Takeshi Sawada, Mari Akimoto, Yuka Sasaki, Hiroaki Fujimori, Yoshinobu Ishikawa, Tadashi Okawara, Tetsumi Irie, Takeji Takamura, Kenji Matsuno, Kengo Inoue, Mitsuko Masutani, Fumiaki Koizumi. Identification of a novel compound, MO2455, that induces poly(ADP-ribose) (PAR) accumulation and inhibits the growth of cancer cells in vitro and in vivo. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4808.
Abstract 4813: Magnetic iron oxide nanoparticles enhance anti-tumor effect of docetaxel on prostate cancer cells via ROS generation and NF-kappa B signaling
Authors: Kojima Kanako , Hashimoto Saho , Sakamaki Rina , Takahashi Sanai , Kasakura Risa , Maruyama Ryo , Nittami Tadashi , Ishiguro Hitoshi , Uemura Hiroji , Watanabe Masatoshi
Published: July 2016

Chemotherapy is one of treatment options for castration-resistant prostate cancer. Especially, docetaxel-based chemotherapy has been shown to improve the quality of life in patients with the advanced disease. However, this needs to be improved because of limitations by lack of specificity, toxicity, and progression of docetaxel-resistance. Thus, combination of docetaxel with other compounds or drugs is needed to overcome these problems. Magnetic iron oxide nanoparticles (MgNPs, Fe3O4) have been investigated for nanomedicine such as drug delivery, cancer diagnosis and therapy. We have also shown that MgNPs would modify the effect of chemotherapy in prostate cancer cells in vitro. The purpose of this study was to analyze the combined effect of docetaxel and non-/carboxyl-modified magnetic nanoparticles (MgNPs/MgNPs-COOH) on a prostate cancer cell line, DU145 and clarify their mechanisms. While only MgNPs produced reactive oxygen species (ROS) and 8-OHdG, MgNPs-COOH did neither produce ROS nor 8-OHdG. The combination of docetaxel and MgNPs-COOH more effectively inhibited cancer cell growth and induced apoptosis compared with combination of docetaxel and MgNPs. Although docetaxel induced NF-kappa B expression, combination of docetaxel and MgNPs inhibited NF-kappa B expression compared with combination of MgNPs-COOH and docetaxel. However, both combinations increased p-Akt expression. These results suggest that MgNPs/MgNPs-COOH may enhance effect of docetaxel on prostate cancer cells via NF-kappa B signaling, however different factors may be involved in these phenomena, leading to new tumor ablation therapies.

Citation Format: Kanako Kojima, Saho Hashimoto, Rina Sakamaki, Sanai Takahashi, Risa Kasakura, Ryo Maruyama, Tadashi Nittami, Hitoshi Ishiguro, Hiroji Uemura, Masatoshi Watanabe. Magnetic iron oxide nanoparticles enhance anti-tumor effect of docetaxel on prostate cancer cells via ROS generation and NF-kappa B signaling. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4813.