bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5474: PD-L1 regulates cisplatin chemoresistance in head and neck squamous cell carcinoma
Authors: Ruffner Randall S. , Ramsey Andrew , O'Malley Bert W. , Li Daqing
Published: August 2015

PD-L1 has been known to play a major role in suppressing the immune system. The effect of PD-L1 has been clinically studied by inhibiting PD-L1 in tumor and tumor-infiltrating immune cells, thereby activating anti-tumor T cells and re-establishing anti-tumor immune responses. Little is known about a unique role of PD-L1 in cisplatin chemoresistance of head and neck squamous cell carcinoma (HNSCC). The aim of the current study is to investigate a novel finding that PD-L1 regulates DNA double strand break (DSB) repairs via the MRE11-RAD50-NBS1 (MRN) complex and contributes to cisplatin chemoresistance in HNSCC.

Well-characterized HNSCC tumor cell lines were used for this study. JHU 006 tumor cell line has a cisplatin resistant phenotype whereas JHU 020 is cisplatin sensitive. PD-L1 expression was determined by quantitative polymerase chain reaction (qPCR) and western blot before and after cisplatin treatment. The interactions between PD-L1 and MRN in DNA DSB mediated chemoresistant pathway were studied. PD-L1 siRNA was used to induce chemosensitization of HNSCC cells to cisplatin.

Our study demonstrates that treatment of HNSCC cells with cisplatin resulted in increased expression of PD-L1 in cisplatin resistant tumor cells, whereas chemosensitive tumor cells showed no change in PD-L1 expression. Additionally, knockdown of PD-L1 using siRNA resulted in downregulation of NBS1, a key protein of the MRN DNA DSB repair complex. However, NBS1 was able to modulate the levels of PD-L1 expression as the use of either NBS1 siRNA or cells that had been transfected with a dominant negative NBS1 mutant resulted in increased PD-L1 expression. The experimental data suggest that PD-L1 may act as an upstream regulator of NBS1 and may facilitate formation of the MRN complex, enhancing repair of cisplatin induced DNA damage, thereby increasing the cell's resistance to chemotherapeutics. Decreasing expression of PD-L1 via siRNA leads to increased sensitivity of HNSCC cells to cisplatin. This highlights the importance of PD-L1 in the development of chemoresitance and suggests a potential therapeutic strategy for patients with cisplatin-resistant HNSCC.

In conclusion, we have identified a novel role for PD-L1 in the development of chemoresistance through its interaction with the MRN complex, which plays a major role in the repair of chemo-induced DNA DSB. Therapies aimed at blocking PD-L1 show great promise because of their ability to enhance both chemotherapeutics and the anti-tumor immune response.

Citation Format: Randall S. Ruffner, Andrew Ramsey, Bert W. O'Malley, Daqing Li. PD-L1 regulates cisplatin chemoresistance in head and neck squamous cell carcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5474. doi:10.1158/1538-7445.AM2015-5474
Abstract 5499: Necuparanib affects tumor progression and invasion in a 3D co-culture system of pancreatic cancer cells and stellate cells
Authors: Krause Silva , Weyers Amanda , Loveluck Katie , Schultes Birgit
Published: August 2015

Pancreatic cancer is one of the most aggressive and deadliest cancers, with only about 5% of patients surviving 5 years past the initial diagnosis. In over 80% of patients the cancer has already spread to distant organs at the time of diagnosis, making it difficult to treat. Most alarmingly, pancreatic cancer is the only cancer for which deaths are predicted to increase over the next few years. Despite advances with new chemotherapy combinations, overall survival outcomes are still dismal and require novel therapeutic approaches. Necuparanib (formerly M402) is a heparan sulfate-like molecule that binds and inhibits multiple heparin-binding growth factors, chemokines, adhesion molecules and enzymes involved in cancer progression and metastasis and as such modulates multiple elements of the tumor microenvironment. In order to further explore the mechanism of action for epithelial-stromal interactions affected by necuparanib, a 3-dimensional culture system mimicking pancreatic cancer was developed containing a co-culture of pancreatic tumor cells and pancreatic stellate cells, the most abundant stromal cell in the pancreas. In this culture system, pancreatic cancer cells form a tumor spheroid embedded in a matrix that is a mixture of type I collagen and basement membrane extract and contains pancreatic stellate cells. Notably, pancreatic cancer cells required the co-culture with pancreatic stellate cells to become invasive in vitro. Conditioned medium derived from pancreatic stellate cells could not mimic this effect indicating that soluble factors are not sufficient to cause invasion into surrounding matrix. Necuparanib inhibited the invasive behavior in a dose-dependent manner. The effect of pancreatic stellate cells on tumor cell invasion and the effect of necuparanib on stromal cells were further explored in this culture system. We showed an effect of necuparanib on proliferation, migration and invasion of pancreatic tumor cells. These studies aid in our understanding of the key biological targets and pathways responsible for necuparanib's anti-tumor effects and support biomarker discovery in the ongoing Phase 2 efficacy study in metastatic pancreatic cancer.

Citation Format: Silva Krause, Amanda Weyers, Katie Loveluck, Birgit Schultes. Necuparanib affects tumor progression and invasion in a 3D co-culture system of pancreatic cancer cells and stellate cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5499. doi:10.1158/1538-7445.AM2015-5499
Abstract 635: Development of anti-cancer ADCs with Concortis’ C-and K-lock technology
Authors: Chen Gang , Zhu Tong , Deng Dylan , Zhang Hong , Miao David
Published: August 2015

Antibody-Drug Conjugation (ADC) is a rapidly growing area and has been widely explored for cancer therapy. In the past decade, numerous progresses have been reported on the identification of proper antibodies, targets validation, discovery of novel payloads, improvement of linkers, as well as the development of new coupling techniques.

We have developed novel conjugation methods, C-lock, K-lock and the combination of the two. C-LockTM conjugation method utilizes a novel linker chemistry to re-connect the reduced disulfide bonds between antibody heavy and light chains, and in the meantime, to introduce a drug to each disulfide bond. While K-LockTM conjugation method is a linker-controlled conjugation technology highly selective on 1 or 2 particular sites among 80-90 Lys side chains of an antibody. The generated ADCs have fewer regioisomers and lower DAR (Drug-Antibody Ratio) while maintaining comparable potency to ADCs from regular conjugation methods. Further purification will give rise to site-specific homogeneous products without needs for cell engineering or enzymatic modification steps. The lead ADCs generated by these technologies showed improved activity both in vitro and in vivo in relevant tumor models, and also exhibited less toxicity compared to commercial standard.

To pursue to the next level, we are currently developing dual drug ADCs which have two different payloads conjugated to single antibody; as well as bi-specific ADCs with either single or dual drug conjugations (2nd generation or ADC-2X). Initial results indicated that these ADCs showed improved activity and specificity in relevant tumor cell lines compared to 1st generation ADCs. Detailed results will be reported. All these data proved that our ADC technologies are unique and superior in antibody drug conjugation and are promising for anti-cancer drug development.

Citation Format: Gang Chen, Tong Zhu, Dylan Deng, Hong Zhang, David Miao. Development of anti-cancer ADCs with Concortis’ C-and K-lock technology. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 635. doi:10.1158/1538-7445.AM2015-635
Abstract 637: Preclinical activity of hLL2-PBD, a novel anti-CD22 antibody-pyrrolobenzodiazepine (PBD) conjugate in models of non-Hodgkin lymphoma
Authors: Zammarchi Francesca , Williams David , Havenith Karin , D'Hooge Francois , Howard Philip W. , Hartley John A. , van Berkel Patrick
Published: August 2015

CD22 is a type I transmembrane sialoglycoprotein, which expression is restricted to the B-cell lineage. CD22 is also found highly expressed on most malignant mature B cells, including follicular non-Hodgkin lymphoma (NHL), marginal zone lymphoma (MZL), mantle cell lymphoma (MCL), diffuse large B-cell lymphoma (DLBCL), small lymphocytic lymphoma (SLL) and chronic lymphocytic leukemia (CLL).

The differential and favorable expression profile of CD22 in normal and tumor tissues, together with its rapid internalization upon binding with a ligand or antibody, make CD22 an attractive target for an antibody drug conjugate (ADC) mediated treatment of B-cell malignancies. hLL2-PBD is an ADC composed of the humanized monoclonal antibody epratuzumab (hLL2) against human CD22 stochastically conjugated via a valine-alanine cleavable, maleimide linker to a PBD dimer. PBD dimers represent a novel class of payloads, which bind in the DNA minor groove and form highly cytotoxic DNA interstrand cross-links. The average drug to antibody ratio (DAR) of hLL2-PBD is 2.

In vitro, hLL2-PBD showed potent and specific cytotoxicity, as assessed by the MTS assay, in the CD22-positive human Burkitt's lymphoma-derived cell lines Ramos and Daudi and the human diffuse large B-cell lymphoma-derived cell line WSU-DLCL2.

In vivo, hLL2-PBD demonstrated potent anti-tumor efficacy in subcutaneously (s.c.) implanted Daudi and Ramos xenograft models. In the Daudi model, hLL2-PBD, administered as a single dose at either 0.1 or 0.3 mg/kg, achieved dose-dependent anti-tumor activity, resulting in significant increase in survival. At 0.3 mg/kg, hLL2-PBD induced complete tumor regression in all treated animals. In the Ramos xenograft model, a single dose of 1 mg/kg of hLL2-PBD achieved strong tumor regression. Moreover, hLL2-PBD achieved a superior anti-tumor activity compared to Hu10F4-vcMMAE, a CD22-targeting ADC with the auristatin payload vcMMAE and a DAR of 4 (Genentech Inc.), when tested at 1 mg/kg, single dose. Pharmacokinetic (PK) analysis of hLL2-PBD in CB.17 SCID mice showed a favorable PK profile, with a half-life of approximately 12 days.

In conclusion, these data demonstrate the potent in vitro and in vivo anti-tumor activity of hLL2-PBD against CD22-positive hematological tumors and warrant further development of this ADC into the clinic.

Citation Format: Francesca Zammarchi, David Williams, Karin Havenith, Francois D'Hooge, Philip W. Howard, John A. Hartley, Patrick van Berkel. Preclinical activity of hLL2-PBD, a novel anti-CD22 antibody-pyrrolobenzodiazepine (PBD) conjugate in models of non-Hodgkin lymphoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 637. doi:10.1158/1538-7445.AM2015-637
Abstract 651: Superior anti-tumor activity compared to T-DM1 in preclinical studies of targeted therapies for her2-positive cancers by a novel her2-ADC ZV0201
Authors: Zhang Hong , Li Zhaohui , Zhu Tong , Cao Sheldon , Chen Gang , Miao David
Published: August 2015

ZV0201 is a her2-targeting ADC based on newly developed K-Lock technology at Concortis. Anti-her2 Antibody ZV02 was conjugated with highly cytotoxic auristatin analogue through a non-cleavable linker to form ZV0201,which mainly consists of DAR2 species. Biochemical analysis indicated that ZV0201 was homogeneous and displayed as a single population after purification. In cellular assay, enhanced anti-tumor activities were observed with this conjugate, compared to T-DM1 in a variety of tumor cell lines. ZV0201 was especially active in cells expressing medium to low level of Her-2. In PK study, ZV0201 had an IC50 about 3-4 days in mouse and was stable for up to 7 days in sera from different species. In xenograft models, a single dose of ZV0201 at low levels completely wiped out the tumors and kept it down for up to 100 days, outperformed T-DM1. Toxicity analysis in rats showed less or comparable toxic effect to that of T-DM1. ZV0201 is currently under further evaluation as a candidate for clinical treatment of her2-positive cancers.

Citation Format: Hong Zhang, Zhaohui Li, Tong Zhu, Sheldon Cao, Gang Chen, David Miao. Superior anti-tumor activity compared to T-DM1 in preclinical studies of targeted therapies for her2-positive cancers by a novel her2-ADC ZV0201. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 651. doi:10.1158/1538-7445.AM2015-651
Abstract 669: BGB-283 effectively enhances MEK inhibitor induced tumor suppression in RAS mutant cancers
Authors: Yuan Xi , Tang Zhiyu , Du Rong , Cheung Shing-Hu , Wei Jing , Zhao Yuan , Du Yunguang , Hao Rui , Hu Xiaoxia , Gong Wenfeng , Liu Yong , Gao Yajuan , Wei Min , Zhou Changyou , Wang Lai , Luo Lusong
Published: August 2015

Mutation in K-RAS, which drives constitutive activation of the mitogen-activated protein kinase (MAPK) signaling pathway, is one of the most frequent genetic alterations in human cancers. Pharmacological targeting RAS mutants directly is extremely challenging and targeted inhibition of K-RAS downstream effector MEK has shown limited clinical activity in suppressing the progression of K-RAS mutant tumors. The reduced sensitivity of K-RAS-mutated cancer cells to MEK inhibitors (MEKi) is associated with feedback phosphorylation of MEK and rebound of phosphorylated ERK levels after prolonged treatment. A synthetic lethal screen provided the rational of targeting both RAF1 and MEK in K-RAS mutated cancers. In this study, we investigated whether combining BGB-283, a potent inhibitor to RAF dimers, and a series of MEKi could achieve better therapeutic effect of the latter. We confirmed that selumetinib (AZD6244) induced strong MEK phosphorylation in K-RAS mutated cancer cells. Either knockdown of B-RAF/C-RAF or addition of BGB-283 in the presence of selumetinib potently inhibited RAF-dependent MEK phosphorylation and led to sustained inhibition of ERK activity. Furthermore, BGB-283 and selumetinib showed synergistic effect in inhibiting proliferation of several non-small cell lung cancer (NSCLC) and colorectal cancer (CRC) cell lines harboring RAS mutations. In vivo, combined dosing of BGB-283 and AZD6244 also exhibited enhanced antitumor activity in K-RAS mutant NSCLC and CRC xenograft models compared to monotherapies. Pharmacodynamic (PD) analysis revealed improved inhibition of ERK phosphorylation in dually treated tumors. Together, these findings suggested that combining RAF dimer inhibitor BGB-283 and MEKi could be a promising strategy in treating RAS mutated cancers.

Citation Format: Xi Yuan, Zhiyu Tang, Rong Du, Shing-Hu Cheung, Jing Wei, Yuan Zhao, Yunguang Du, Rui Hao, Xiaoxia Hu, Wenfeng Gong, Yong Liu, Yajuan Gao, Min Wei, Changyou Zhou, Lai Wang, Lusong Luo. BGB-283 effectively enhances MEK inhibitor induced tumor suppression in RAS mutant cancers. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 669. doi:10.1158/1538-7445.AM2015-669
Abstract 724: Anti-tumor effect of Dasatinib in HER2 positive breast cancer with Trastuzumab resistance
Authors: Takeda Tatsuaki , Kanzaki Hirotaka , Toyooka Shinichi , Watanabe Mototsugu , Ohtsuka Tomoaki , Suzawa Ken , Hashida Shinsuke , Maki Yuho , Yamamoto Hiromasa , Soh Junichi , Asano Hiroaki , Tsukuda Kazunori , Miyoshi Shinichiro , Kitamura Yoshihisa , Sendo Toshiaki
Published: August 2015

[Background]

Overexpression of human epidermal growth factor receptor 2 (HER2) was observed in approximately 20%-25% of breast cancers and they are classified in HER2-positive breast cancer. Trastuzumab is a therapeutic drug for the first choice for HER2-positive breast cancer, showing good response. However, acquired resistance to trastuzumab is one of the critical clinical issues in breast cancer treatment, especially in the patients with recurrent breast cancer. Therefore it is necessary to develop the effective therapy to overcome resistance. In this study, we established a trastuzumab-resistant breast cancer cell line from a trastumab-sensitive cell line with HER2 amplification (BT-474), and demonstrated anti-tumor effect of dasatinib in the breast cancer cell with trastuzumab resistance.

[Methods]

Trastuzumab-resistant breast cancer cell line (BT-474-R) was established by treating BT-474 cells for long-term exposing with trastuzumab. We performed cell viability assay to analyze drug sensitivity. Then, we performed quantitative PCR and western blotting to investigate expression and activation of HER2 and related molecules. Cell viability assay and signal analysis were performed with or without trastuzumab and/or dasatinib treatment.

[Results]

Proto-oncogene tyrosine-protein kinase Src was up-regulated and activated in BT-474-R. Signaling molecules, such as Akt and MAPK, were also activated. Dasatinib, which is known as a Src inhibitor, suppressed the activation of signal molecules and cell survival of BT-474-R. Moreover, dasatinib treatment recovered sensitivity to trastumab in the BT-474-R with down-regulation of Src phosphorylation.

[Conclusion]

Src plays an important role in acquired resistance to trastumab in breast cancer. Our data also suggest that inhibition of Src may become the new strategy to overcome trastuzumab resistance.

Citation Format: Tatsuaki Takeda, Hirotaka Kanzaki, Shinichi Toyooka, Mototsugu Watanabe, Tomoaki Ohtsuka, Ken Suzawa, Shinsuke Hashida, Yuho Maki, Hiromasa Yamamoto, Junichi Soh, Hiroaki Asano, Kazunori Tsukuda, Shinichiro Miyoshi, Yoshihisa Kitamura, Toshiaki Sendo. Anti-tumor effect of Dasatinib in HER2 positive breast cancer with Trastuzumab resistance. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 724. doi:10.1158/1538-7445.AM2015-724
Abstract 792: ASN002: A novel dual SYK/JAK inhibitor with strong antitumor activity
Authors: Reddy Sanjeeva , Damle Nitin K. , Venkatesan Aranapakam M. , Thompson Scott K. , Rao Niranajan , Smith Roger A. , Gupta Sandeep
Published: August 2015

Spleen tyrosine kinase (SYK) and Janus kinase (JAK) play important roles in the pathogenesis of various types of lymphomas, solid tumors, myeloproliferative and inflammation disorders. Inhibition of these targets has been shown to suppress tumor growth in various preclinical and/or clinical studies. Most B-cell malignancies are driven by the B-cell receptor (BCR) pathway, and SYK plays a critical role in this pathway by initiating and amplifying the signal from the receptor. JAK kinases (JAK1, JAK2, JAK3 and TYK2), upon stimulation by various growth factors and cytokines, phosphorylate signal transducers and activators of transcription family proteins (STAT1 -5) which activate various downstream target genes. ASN002 is a novel and potent dual inhibitor of SYK and JAK kinases with IC50 values of 5-46 nM in biochemical assays. In mechanistic cell-based studies involving IgE and cytokine stimulations, ASN002 strongly suppressed the SYK and JAK family kinase signaling pathways measured as pLAT and pSTAT levels, respectively. The compound showed anti-proliferative activity in a broad panel of human cancer cell lines including DHL6, DHL4, OCI-LY10, H929, Pfeiffer, HT-1376, and Lovo, suggesting activity in both solid and hematological tumor types. In a multiple myeloma (H929) xenograft model, ASN002 exhibited significant efficacy in inhibiting tumor growth (>95%). It also significantly delayed the onset of hind limb paralysis in the human erythroleukemia (HEL) mouse model. ASN002 has good oral bioavailability, metabolic stability, is not a Pgp substrate, and shows little to no inhibition of CYP450 isozymes. ASN002 showed a favorable safety profile in rat and dog toxicology studies. A Phase I/II clinical study is being planned for the evaluation of ASN002 in lymphomas (diffuse large B cell lymphoma, mantle cell lymphoma, follicular lymphoma) and solid tumors.

Citation Format: Sanjeeva Reddy, Nitin K. Damle, Aranapakam M. Venkatesan, Scott K. Thompson, Niranajan Rao, Roger A. Smith, Sandeep Gupta. ASN002: A novel dual SYK/JAK inhibitor with strong antitumor activity. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 792. doi:10.1158/1538-7445.AM2015-792
Abstract 899: High fat diet induced DNA methylation at transcription factor binding region and repressed gene expression of a metastasis suppressor E-cadherin in primary site of murine metastatic breast cancer (MBC), and promoted invasion of MBC cells to lung and liver
Authors: Zhang Yukun , Wang Wendan , Yang Xujuan , Helferich William G.
Published: August 2015

Breast cancer (BC) is the most prevalent type of cancer among women in the US. BC survival rate has long been compromised by metastasis. Consumption of a high fat diet (HFD) is associated with increased BC risk. However, the underlying molecular mechanisms remain inconclusive. E-cadherin (Cdh1) is a metastasis suppressor, the loss of which promotes tumor invasion. We aimed to examine the effects of a HFD containing 47% kcal from fat on metastatic breast cancer (MBC) using preclinical syngeneic mouse models. To access the dietary effect on metastatic mammary tumor, we injected MBC cells into the mammary duct of BALB/c mice. To evaluate the dietary effect on the spread of MBC from bone to lung and liver tissues, MBC cells were inoculated into tibia cavity of BALB/c mice. Growth of MBC at the injection and inoculation site, and invasion of MBC to other organs were monitored in real-time by the bioluminescence imaging (BLI) system. Three weeks post injection, animals were sacrificed and tissues samples were collected. In summary, our results showed that HFD promoted the invasion of MBC cells to lung and liver of mice. H&E staining showed that there were significantly more lung tumors in the HFD group than control group in the tibial injected animals (12.9±1.6, 8.9±1.1, P<0.05), as well as more mice with liver tumors in HFD group (7 out of 16 mice with liver tumors in HFD group, 0 out of 17 mice with liver tumors in control group). Expression of Cdh1mammary tumor of mice was decreased by HFD. Intensity of methylation at the CpG-rich promoter region, where transcription factors bind, was increased by HFD in the mammary tumor. As the first to report that HFD induced DNA methylation and decreased the expression of Cdh1 in the metastatic mammary tumor, we proposed a mechanism by which HFD enhanced the invasiveness of MBC. Having laid a base and provided clues on HFD and MBC, this study also shed light on the intriguing interactions of nutrient epigenome and BC. Future studies are needed to further extrapolate our findings into the link between diet and disease in BC patients.

Citation Format: Yukun Zhang, Wendan Wang, Xujuan Yang, William G. Helferich. High fat diet induced DNA methylation at transcription factor binding region and repressed gene expression of a metastasis suppressor E-cadherin in primary site of murine metastatic breast cancer (MBC), and promoted invasion of MBC cells to lung and liver [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 899. doi:10.1158/1538-7445.AM2015-899
Abstract 94: Melatonin inhibits stemness of glioblastoma cancer stem-like cells via regulation of histone methylation
Authors: Lee Hyemin , Jung Ji Hoon , Lee Hyun Joo , Jeong Myoung Seok , Jung Deok-Beom , Kwon Hee Young , Kim Sung-Hoon
Published: August 2015

The pineal gland hormone melatonin (N-acetyl-5-methoxytryptamine) is well known as an anticancer effector. Recently, a variety of studies have shown that melatonin induces apoptosis in various cancer cell types such as colon cancer, Ewing sarcoma, hepatic cancer, prostate cancer and breast cancer cells. Glioblastoma cancer stem-like cells (GCSLC) are the most common and aggressive primary brain tumor in adults. In the present study, we found that melatonin significantly decreased the sphere formation of GCSLC, and attenuated the expression of c-Myc genes. Furthermore, melatonin suppressed expression of H3K4me3 and H3K79me3 around c-Myc promoter region by Western blotting and Chip assay. Of note, melatonin suppressed the expression of several stemness markers including nestin in GCSLC. Overall, our findings suggest melatonin as a potent anticancer stem cell agent for GCSLC.

Citation Format: Hyemin Lee, Ji Hoon Jung, Hyun Joo Lee, Myoung Seok Jeong, Deok-Beom Jung, Hee Young Kwon, Sung-Hoon Kim. Melatonin inhibits stemness of glioblastoma cancer stem-like cells via regulation of histone methylation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 94. doi:10.1158/1538-7445.AM2015-94
Abstract 945: Synthetic lethal screen identifies Aurora A as a selective target in HPV driven cervical cancer
Authors: Gabrielli Brian G. , Bokhari Fawzi , Ranall Max , Oo Zay Yar , Stevenson Alex , Wang Weili , McKee Sara , Leggatt Graham , Leo Paul , Gonda Thomas J. , McMillan Nigel AJ
Published: August 2015

HPV has been identified as the definitive agent in cancers of the cervix, penis, vulva, vagina, anus, skin, eye, and head and neck, and is responsible for 5% of the total cancer burden worldwide. HPV oncogenes disable a number of tumour suppressor pathways, including p53 and Rb, contributing to the transformed phenotype. We have performed an siRNA screen using the kinome (779 genes) library to identify genes that when depleted are synthetically lethal with HPV transformation. The primary and validations screens have confirmed Aurora A kinase (AURKA) as a potential synthetic lethal target selective for HPV transformed cells. In vitro research using the investigational selective small molecule AURKA inhibitor alisertib found alisertib to be significantly more potent towards the HPV transformed cells, and selectively promoted apoptosis in the HPV cancers. The drug was shown to target the HPVE7 oncogene, the level of expression of this oncogene possibly influencing sensitivity. Apoptosis was sensitive to Mcl-1 but not Bcl-2 over expression, indicating that the mechanism is associated with the proteolytic destruction of Mcl-1 in the extended mitosis in the alisertib treated HPV cancer lines. Xenograft experiments with cervical cancer cell lines showed alisertib inhibited growth of HPV and non-HPV xenografts during treatment. The non-HPV cancer growth was delayed, but in two separate HPV cancers models, regression and no resumption of growth was detected at even 50 days post-treatment. A second transgenic model of premalignant disease driven solely by HPVE7 similarly demonstrated sensitivity to drug treatment. These findings provide preclinical evidnce that alisertib warrants evaluation as a potential targeted compound with activity in HPV-transformed cervical cancer and premalignant disease that may have application to other HPV driven cancers.

Citation Format: Brian G. Gabrielli, Fawzi Bokhari, Max Ranall, Zay Yar Oo, Alex Stevenson, Weili Wang, Sara McKee, Graham Leggatt, Paul Leo, Thomas J. Gonda, Nigel AJ McMillan. Synthetic lethal screen identifies Aurora A as a selective target in HPV driven cervical cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 945. doi:10.1158/1538-7445.AM2015-945
Abstract 964: GATA3 modulates chromatin structure to establish active enhancers in breast cancer cells
Authors: Takaku Motoki , Grimm Sara A. , Shimbo Takashi , Perera Lalith , Machida Shinichi , Kurumizaka Hitoshi , Wade Paul A.
Published: August 2015

Master transcription factors regulate cell-type-specific gene expression to define cellular identities. One such gene, GATA3, is a key regulator of multiple cellular programs, including T lymphocyte development, mammary luminal epithelial cell differentiation and trophoblast development. Recently, comprehensive genomic analysis has identified GATA3 as one of the most frequently mutated genes in breast cancer. It is also known that GATA3 expression levels directly correlate with favorable prognosis. These findings strongly suggest that GATA3 plays a critical role in tumorigenesis. However, the molecular mechanism(s) underlying GATA3-mediated gene regulation in breast cancer cells is not clearly defined. GATA3 participates in a complicated regulatory network with FOXA1 and ER-alpha, governing the transcriptional program in luminal tumors. Biochemical analyses indicate that: (1) GATA3 binds to chromatin in an estrogen-independent manner, (2) GATA3 acts upstream of FOXA1. These studies suggest GATA3 may act as a pioneer factor, which is capable of independently associating with closed chromatin and modulating chromatin structure to establish an active enhancer. In order to investigate GATA3 function as a pioneer transcription factor, we chose the MDA-MB-231 breast cancer cell line, which is GATA3, FOXA1 and ER-alpha negative, and established stable cell lines expressing wild-type GATA3 or GFP as a control. Consistent with previous results, GATA3-expressing cells represented an epithelial phenotype at the cellular and molecular level. To determine whether GATA3 can direct reprogramming of chromatin conformation, we performed genome-wide analyses of the chromatin binding activity of GATA3 and its impact on histone modifications and chromatin structure. We will present recent results describing how GATA3 licenses enhancer function to direct the luminal transcriptional program.

Citation Format: Motoki Takaku, Sara A. Grimm, Takashi Shimbo, Lalith Perera, Shinichi Machida, Hitoshi Kurumizaka, Paul A. Wade. GATA3 modulates chromatin structure to establish active enhancers in breast cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 964. doi:10.1158/1538-7445.AM2015-964
Abstract 988: Triple negative breast cancer cells have higher dependence on mitophagy for their survival as compared to hormone positive breast cancer cells
Authors: Dikshit Bhawana , Rai Aakansha , Roy Soumya Sinha
Published: August 2015

Autophagy is a key pathway utilised by the cells to clear the dysfunctional cellular components and maintain homeostasis. However cancer cells having defective apoptosis, deploy autophagy as a survival mechanism by limiting tumor necrosis and metabolic stress. Autophagy has been reported to be upregulated in triple negative breast cancers which are categorized as the most aggressive breast cancers with poor prognosis. Nevertheless the exact mechanism of autophagic upregulation in TNBC is still elusive. Therefore analyzing pathways specifically altered in these tumors might provide better targets for therapeutic intervention.

Results:

In the present study we observed higher basal autophagy in TNBC cell line MDA MB 231 as compared to triple positive MCF7 cells as analyzed by the presence of higher number of GFP-LC3 puncta in the former. Treatment with 20μM of autophagy inhibitor chloroquine for 48 hrs led to significant cell death in TNBC cell line as compared to MCF7 whereas treatment with 20μM of PI3K inhibitor wortamannin did not significantly affected the survival of TNBC and MCF7 cells. Further the analysis of autophagy markers revealed higher LC3B and Beclin1 levels as compared to ATG5 and ATG7 levels in MDA MB 231 cells both at mRNA and protein levels as analyzed by qPCR and western blot. Also the knockdown of ATG7 by ATG7 shRNA did not significantly affected the survival of TNBC cells.

Conclusion:

Thus in this study we aim to highlight the difference in the expression of autophagy markers and the effect of autophagy inhibitors wherein only late phase of autophagy seems to significantly upregulated in TNBC. The difference can be attributed to the dependence of TNBC cells upon ‘late phase autophagy’ or particularly ‘mitophagy’ that is crucial for rapid clearance of misfolded proteins and dysfunctional mitochondria as has been reported in TNBCs. Further study to dissect the mechanism of selective upregulation of ‘late phase autophagy’or ‘mitophagy’ in TNBC might provide novel targets for treatment strategies in these breast cancers.

Citation Format: Bhawana Dikshit, Aakansha Rai, Soumya Sinha Roy. Triple negative breast cancer cells have higher dependence on mitophagy for their survival as compared to hormone positive breast cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 988. doi:10.1158/1538-7445.AM2015-988
Abstract 991: Role of autophagy as potential molecular mechanism in trastuzumab-induced cardiotoxicity
Authors: Mohan Nishant , Shen Yi , Wu Wen Jin
Published: August 2015

Autophagy is basic catabolic cellular process which is essential for maintaining cellular homeostasis during nutrient starved and stress conditions. Even though autophagy is altered in various cardiovascular diseases including cardiomyopathy and heart failure, its precise role in heart conditions remains ambiguous. Trastuzumab is a humanized monoclonal antibody approved for treatment of HER2-positive breast cancer. Trastuzumab treatment has been shown to induce considerable cardiotoxicity. Molecular mechanism for trastuzumab-induced cardiotoxicity remains largely unclear. In this study, we investigated the role of autophagy as potential molecular mechanism in trastuzumab-induced cardiotoxicity. We treated human primary cardiomyocytes with trastuzumab at different time points, and then examined the expression of prominent autophagic markers such as LC3A/B, Beclin 1 and Bcl-2 by western blotting. Results divulged that expression levels of LC3A/B were markedly decreased in cardiomyocytes after 24 and 48 h of trastuzumab treatment. Beclin 1 protein levels also significantly decreased, although Bcl-2 expression was increased. These results indicate that downregulation of Beclin 1 and upregulation of Bcl-2 after trastuzumab treatment could potentially impede the formation of autophagosomes resulting in inhibition of autophagy. Collectively, these data indicate that autophagy plays a beneficial role in normal cardiac tissues by preventing the accumulation of abnormal proteins or damaged organelles. However, trastuzumab treatment may inhibit the autophagy, resulting in cardiomyopathy.

Citation Format: Nishant Mohan, Yi Shen, Wen Jin Wu. Role of autophagy as potential molecular mechanism in trastuzumab-induced cardiotoxicity. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 991. doi:10.1158/1538-7445.AM2015-991
Abstract CT210: Precision medicine for advanced pancreas cancer: the individualized molecular pancreatic cancer therapy (IMPaCT) trial
Authors: Chantrill Lorraine , Simpson Skye , Johns Amber , Martyn-Smith Mona , Chou Angela , Watson Clare , Nagrial Adnan , Chin Venessa , Sebastian Lucille , Yip Sonia , Simes John , Pavlakis Nick , Grimison Peter , Asghari Ray , Harvey Sandra , Biankin Andrew
Published: August 2015

Background: The Individualized Molecular Pancreatic Cancer Therapy (IMPaCT) trial is designed to exploit results from whole genome sequencing of pancreatic cancer collected under the auspices of the ICGC in Australia. Results showed that small subsets of patients had actionable changes in their tumor genome that could be druggable with currently available therapies. Only 7% of cases were found to be KRAS wildtype, and this phenotype may enrich for susceptibility to EGFR inhibition. Her2 positivity occurs in 2% and may confer sensitivity to Her inhibition. Tumors displaying defects in the DNA damage repair pathway (∼5%) respond to DNA damaging chemotherapy.

Trial Design: The IMPaCT trial has recently been amended to a single arm pilot study of first line molecularly guided therapy for advanced pancreas cancer. Patients are permitted to begin their first cycle of chemotherapy with gemcitabine with or without nab-paclitaxel while awaiting molecular results.

We screen potential patients for the three molecular targets: Her2 amplification: trastuzumab + gemcitabine; KRAS wildtype: erlotinib + gemcitabine; and DNA damage: platinum-based chemotherapy.

In our initial cohort of patients who underwent resection with curative intent, 70% recurred. Recurrence occurred 16m after initial surgery. Collection of tissue commenced in 2009. The first site to open was in April 2013 by which time, only 8 patients for whom we had complete sequence data and actionable mutations were still alive, so we changed the trial to screen de novo metastatic patients.

Using the WGS data, we constructed a custom sequencing panel to use DNA extracted from FFPE core biopsies to screen in real time for mutations in KRAS, BRCA2, BRCA1, PALB2 and ATM. Her2 screening is undertaken with IHC and FISH.

We have screened 89 cases in 18m, 8 have relevant molecular targets. The average time from biopsy to delivery of results is 21d. 2 of the 8 eligible cases have commenced precision therapy on trial.

Citation Format: Lorraine Chantrill, Skye Simpson, Amber Johns, Mona Martyn-Smith, Angela Chou, Clare Watson, Adnan Nagrial, Venessa Chin, Lucille Sebastian, Sonia Yip, John Simes, Nick Pavlakis, Peter Grimison, Ray Asghari, Sandra Harvey, Andrew Biankin. Precision medicine for advanced pancreas cancer: the individualized molecular pancreatic cancer therapy (IMPaCT) trial. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr CT210. doi:10.1158/1538-7445.AM2015-CT210
Abstract CT219: Clinical and immunological analysis in a phase II trial of the glypican-3 peptide vaccine for patients with ovarian clear cell carcinoma
Authors: Suzuki Shiro , Shibata Kiyosumi , Kikkawa Fumitaka , Nakatsura Tetsuya
Published: August 2015

Compared with other epithelial ovarian carcinoma subtypes, ovarian clear cell carcinoma (OCCC) is associated with a poorer prognosis and increased chemoresistance. Therefore, new treatment modalities are urgently required for patients with OCCC refractory to chemotherapy. Glypican-3 (GPC3) is useful not only as a novel tumor marker, but also as an oncofetal antigen for immunotherapy. It is specifically overexpressed in hepatocellular carcinoma (HCC). Previous studies demonstrated that GPC3 was also overexpressed in several malignant tumors, including OCCC. We previously reported the safety of and immunological and clinical responses to a GPC3-derived peptide vaccine in a phase I clinical trial of patients with advanced HCC. Although the efficacy of the GPC3-derived peptide vaccine against HCC patients was evaluated, other GPC3-positive cancer patients have not yet been investigated. Therefore, we conducted a phase II trial to evaluate the clinical outcome of OCCC patients treated with a GPC3-derived peptide vaccine (UMIN-CTR: 000003696).

In this study, we describe the effect of vaccination with the HLA-A24 or A2-restricted GPC3 peptide on patients with OCCC. The patients were divided into three groups such as adjuvant therapy group, combined therapy group (combined to second-line chemotherapy) and recurrence or advanced group (single of vaccine treatment). The dose of GPC3 peptide injected was 3 mg per body. Patients received the intradermal injection of GPC3 peptide emulsified with incomplete Freund's adjuvant. Vaccinations were carried out biweekly from the first until the 6th and repeated at 6-week intervals after the 7th. Immunological responses were analyzed by ex vivo IFN-γ enzyme-linked immunospot assay (ELISPOT).

Seventy OCCC patients were entered into clinical trial until the end of October 2014. In adjuvant group, twenty-nine of thirty-five patients have no recurrence. Recurrence pattern of all 6 patients was peritoneal metastasis. Three of twenty-nine patients with refractory OCCC achieved a significant clinical response. Ex vivo IFN-γ ELISPOT analysis in most OCCC patients revealed vaccine-induced immune reactivity against the GPC3 peptide. Our current data provide preliminary evidence of clinically meaningful benefit for GPC3 peptide vaccines in OCCC and support further evaluation of this approach in these patient populations.

Citation Format: Shiro Suzuki, Kiyosumi Shibata, Fumitaka Kikkawa, Tetsuya Nakatsura. Clinical and immunological analysis in a phase II trial of the glypican-3 peptide vaccine for patients with ovarian clear cell carcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr CT219. doi:10.1158/1538-7445.AM2015-CT219
Abstract CT311: Results of a phase I/IIa dose-escalation study of the combination of decitabine and genistein against advanced solid tumors
Authors: Raynal Noël J. , Kassouf Elie , Daigneault Luc , Colin Patrick , Plante Isabelle , Lassonde Guylaine , Momparler Richard , Charbonneau Michel , Blais Normand
Published: August 2015

Background: Epigenetic aberrations, including DNA hypermethylation of tumor suppressor genes are a common feature in solid tumors. Thus, targeting epigenetic pathways is a promising approach for cancer chemotherapy. However, only occasional proof-of-principle responses can be seen in solid tumors. The activity of hypomethylating drugs, such as decitabine could be improved by a treatment combination. Preclinical studies have suggested that adding genistein, a natural isofavone may synergize with demethylating drugs and improve treatment results.

Methods: Here, we describe a phase I/IIa dose-escalation study of decitabine with a fixed dose of genistein. Primary objective of the phase I trial was to determine the Maximum Tolerated Dose (MTD) and to evaluate pharmacokinetic parameters in patients with advanced solid tumor. The objective of the phase IIa was to assess its efficacy in lung cancer. Decitabine was administered over 10-hours at increasing doses (60, 120, 240 mg/m2) with continuous administration of genistein 300 mg/day orally. Treatment was repeated every 4 to 6 weeks.

Results: For the phase I, ten patients with advanced solid tumors were recruited. The recommended dose of decitabine (for the phase IIa) was 120 mg/m2 with neutropenia as limiting side effect. Decitabine at 120 mg/m2 and genistein produced plasma levels of 0.62 ± 0.06 μM and 8.5 ± 5.6 μM, respectively. The drug combination was well tolerated and produced stable disease for more than 7 months (7-14 months) in 50% of the patients. One patient had a 50% reduction in tumor burden after 6 months of therapy. In the phase IIa trial against advanced lung cancer, patients progressed rapidly, within 2 months of treatment mainly because of the apparition of new lesions in the liver.

Conclusion: The combination of decitabine and genistein is well-tolerated in advanced solid tumors and shows interesting anticancer effects. This study on decitabine and genistein warrants future investigations to address this issue of liver metastasis in advanced lung cancer.

Citation Format: Noël J. Raynal, Elie Kassouf, Luc Daigneault, Patrick Colin, Isabelle Plante, Guylaine Lassonde, Richard Momparler, Michel Charbonneau, Normand Blais. Results of a phase I/IIa dose-escalation study of the combination of decitabine and genistein against advanced solid tumors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr CT311. doi:10.1158/1538-7445.AM2015-CT311
Abstract LB-002: A novel c-Met/EGFR bispecific targeting antibody drug conjugate for NSCLC
Authors: Chen Gang , Li Lingna , Muyot Pia , Gros Edwige , Zhang Yanliang , Sun Yingqing , Zhang Hong , Fu Yanwen , Lee Alice , Cao Jian , Kaufmann Gunnar , Miao Zhenwei
Published: August 2015

c-Met and EGFR are both widely and highly expressed, share and cross talk common signaling pathways in a variety of carcinomas including lung, breast, ovary, kidney, colon, thyroid, liver, and gastric carcinomas. Therapeutics like tyrosine kinase inhibitors (TKIs) and monoclonal antibodies, targeting EGFR and c-Met are on the cutting-edge of cancer therapy. In preclinical studies and clinical trials, though these anti-c-Met and EGFR therapeutics showed promising anti-tumor activities but usually not sufficient for sustained treatment efficacy, their individual efficacies are limited due to the development of resistance. c-Met amplification has been considered to be a major escape route for EGFR-targeted therapies. We believe that antibody drug conjugates (ADCs) offer the promise and potential of delivering potent anti-tumor activity with the advantage of reduced side effects. We generated a novel bispecific antibody drug conjugate containing a proprietary human anti-c-Met antibody and anti-EGFR antibody, and a potent toxin by our novel C-lock conjugation method. The conjugate retained high binding affinity and targeting both c-Met and EGFR on tumor cell surface. The ADC showed potent cell killing in a lower nM range in a variety of c-Met and EGFR positive cell lines in vitro and strong in vivo anti-tumor efficacy in several c-Met and EGFR positive human NSCLC xenograft models without significant toxicity. The in vivo anti-tumor growth efficacy of bispecific c-Met/EGFR targeting antibody conjugates is superior to either single anti-c-Met or EGFR ADC.

Citation Format: Gang Chen, Lingna Li, Pia Muyot, Edwige Gros, Yanliang Zhang, Yingqing Sun, Hong Zhang, Yanwen Fu, Alice Lee, Jian Cao, Gunnar Kaufmann, Zhenwei Miao. A novel c-Met/EGFR bispecific targeting antibody drug conjugate for NSCLC. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-002. doi:10.1158/1538-7445.AM2015-LB-002