Browsing Over 138 Presentations
1P - PIWI proteins play oncogenic functions in pancreatic cancer (ID 142)
- W. Li
- W. Li
- J. Martinez Useros
- M. Fernández-Aceñero
- N. García Carbonero
- J. García-Foncillas
Abstract
Background
Human homologues of PIWI proteins identified are PIWIL1, PIWIL2, PIWIL3 and PIWIL4 (Sasaki et al. 2003). Aberrant expression of these proteins has been associated with hallmarks of cancer, and have also a potential prognostic and diagnostic markers for different cancers (Suzuki et al. 2012). However, their functional and clinical significance in pancreatic ductal adenocarcinoma (PDAC) remains unknown. The purpose of this study was to dissect the role of PIWI proteins and their prognostic relevance.
Methods
PIWI proteins expression were analyzed by western blot in human PDAC derived cell lines and one non-transformed pancreatic cell line. Functional experiments were performed with PIWIL3 and/or PIWIL4 downregulated PDAC derived cell lines and one non-transformed cell line. Immunohistochemistry was performed to evaluate expression of PIWI proteins in 124 PDAC samples from Fundacion Jimenez Diaz Hospital, and with 124 validation cohort from TGCA. Then, association between PIWI proteins expression and survival was assessed.
Results
Only PIWIL3 and PIWIL4 showed differential expression in PDAC cell lines. Both wound-healing and transwell assay showed a decrease in migration ratio after PIWIL3 and/or PIWIL4 downregulation (P < 0.05). Furthermore, both PIWIL3 and/or PIWIL4 are necessary for the maintenance of undifferentiated phenotype highlighted by a reduction in size and number of pancreatic spheres after PIWIL3 and/or PIWIL4 downregulation (P < 0.05). On the other hand, PIWIL1 associated with shorter survival (P = 0.056), and this finding was validated in the TGCA cohort (P = 0.021). PIWIL2 associated significantly to shorter survival (P = 0.046) in our training set, and validation set exhibited a high trend toward significance (P = 0.051). Although PIWIL3 and PIWIL4 did not show association with survival in our training set, validation set revealed a statistically significant association of PIWIL4 with shorter overall survival (P = 0.027).
Conclusions
The present study demonstrate that PIWIL3 and PIWIL4 regulates PDAC aggressiveness by inhibiting cell migration and regulate undifferentiated phenotype of cancer cells. Furthermore, PIWIL1, PIWIL2 and PIWIL4 are potential prognostic biomarkers in PDAC.
Legal entity responsible for the study
Fundación Instituto de Investigación Sanitaria - Fundación Jiménez Díaz (G-85874949).
Funding
Spanish Ministry of Economy and Competitiveness.
Disclosure
All authors have declared no conflicts of interest.
5P - Establishment and application of a panel of PBMC-humanized mouse tumor models in cancer immunotherapy (ID 132)
- L. Bourre
- L. Zhang
- S. Qi
- H. Wu
- L. Zhao
- X. An
- W. Tan
- X. Fu
- M. Qiao
- Q. Shi
- W. Yang
Abstract
Background
To meet the rapidly growing I/O market, the demands for fast, relevant and cost effective mouse tumor model systems are also increasing. We developed a panel of straightforward humanized tumor models, designated as MiXeno platform.
Methods
CrownBio has established a sizable collection of MiXeno models where human PBMCs were reconstituted in the mouse system for the evaluation in vivo activity of immune checkpoint inhibitors or immune-modulators. These MiXeno models were characterized with tumor response to anti-PD-1 and anti-CTLA4 antibodies, and onset of possible graft versus host disease (GVHD) or graft versus tumor response (GVT) under different settings. To engage both host immune system and tumor antigens, we have developed some specific Mixeno tumor models by inoculating tumor cells over-expressing specific anti-tumor antigens (e.g. EGFR, CD47, Braf or PD-L1) into PBMC-humanized immunocompromised mice. Moreover, to improve capacity and consistency of MiXeno platform, we are conducting studies to characterize and validate commercialized frozen PBMCs for MiXeno model establishment.
Results
Models with over-expression of a variety of tumor antigens (e.g. EGFR, CD47, Braf, PD-L1...) were used to develop specific Mixeno tumor models. Meanwhile, in order to overcome the limitation of PBMC shortage, commercialized PBMC has been purchase and implanted into several xenograft models, and exhibit consistent tumor growth with fresh PBMC, as well as human immune component reconstitution. Up to date, a variety of test articles of different categories, including checkpoint inhibitors, T cell modulators and bispecific T cell engagers (e.g. EpCam-CD3, CD47/CD3, BCMA/CD3) have been evaluated using this platform. Merchandized I/O drugs, such as Pembrolizumab, are being tested in commercialized PBMC implanted immunocompromised mice.
Conclusions
MiXeno platform are valid model system for the human immuno-modulatory drugs including bispecific antibodies evaluation and will be optimized by introduction of specific Mixeno tumor models, commercial PBMC and B2M mice.
Legal entity responsible for the study
CrownBio.
Funding
CrownBio.
Disclosure
L. Bourre, L. Zhang, S. Qi, H. Wu, L. Zhao, X. An, M. Qiao, Q. Shi, W. Yang: Employee: CrownBio. All other authors have declared no conflicts of interest.
6P - Prognostic significance of neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) in non-small cell lung cancer (NSCLC) treated with immune checkpoint inhibitors (ID 197)
- S. Amaral
- S. Amaral
- M. Casal Moura
- J. Carvalho
- A. Chaves
- E. Jesus
- G. Sousa
Abstract
Background
Immunotherapy with programmed death receptor-1 (PD-1) antibodies has changed the paradigm of advanced NSCLC treatment. These checkpoint inhibitors showed better outcomes compared with standard treatment but reliable predictive markers are still lacking. High pre-treatment NLR and PLR have been associated with poor prognosis in several tumor types and recent studies suggest a potential role also in NSCLC. We thus conducted this study to evaluate the prognostic significance of NLR and PLR in our patients.
Methods
All patients with locally advanced and metastatic NSCLC treated with nivolumab and pembrolizumab from February 2016 to October 2018 were enrolled. NLR and PLR were determined by the division of neutrophils and platelets by lymphocytes in peripheral blood. Kaplan Meier method and Cox proportional hazardous analysis were conducted to assess the impact of NLR, PLR and other clinical factors on overall survival (OS) and progression free survival (PFS).
Results
Thirty-two patients were treated, 20 with nivolumab and 12 with pembrolizumab. Median age was 61 (40-82); 63% were male; 91% had an ECOG PS ≤ 2; 37% received ≥ 2 prior systemic therapies and 78% had stage IV disease. Increased NLR or PLR values above mean were independent predictive factors for decreased PFS (11 vs. 6 months, HR 3.33 95%CI 0.97 - 11.3, p = 0.056 and 12 vs. 6 months, HR 3.9 95%CI 1.19 - 12.8, p = 0.025, respectively). NLR and PLR values higher than percentil 25 were predictive factors, when used in combination, for decreased OS (21 vs. 11 months, HR 12.363 95% CI 1.303 - 117.291, p = 0.028 and 13 vs. 11 months, HR 3.9 95%CI 1.19 - 12.8, p = 0.025, respectively). Other clinical factors (i.e. histology, tobacco use, age, gender, ECOG PS, metastatic sites) did not present any implication for OS and PFS, as determined by multivariate analyses.
Conclusions
Elevated pre-treatment NLR and PLR are associated with shorter OS and PFS in our cohort independently of other prognostic factors. Our results reinforce the potencial role of these markers as a predictive factor of poor prognosis for NSCLC patients. Prospective studies are warranted to validate these findings.
Legal entity responsible for the study
Susana Rocha Amaral.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
10P - Safety profile of epigenetic therapies in early phase trials: Do epidrugs deserve specific drug development processes? (ID 105)
- L. Leroy
- L. Leroy
- T. Satar
- C. Baldini
- P. Martin-Romano
- A. Hollebecque
- J. Michot
- V. Ribrag
- C. Massard
- X. Paoletti
- S. Postel Vinay
Abstract
Background
Targeting the epigenome has demonstrated efficacy in hematological malignancies, and results of recent phase 1 (P1) trials have shown promising activity in solid tumors. The number of novel epidrugs is increasing exponentially, with several first-in-class, first-in-human selective compounds now evaluated in P1 trials. Accurate knowledge of their safety profile and toxicity management beyond cycle 1 is essential to appropriate P2 dose recommendation.
Methods
All patients (pts) with hematologic or solid tumors enrolled in at least one epidrug P1 trial at Gustave Roussy Drug Development Department were retrospectively analysed. Baseline pts characteristics, treatment-related adverse events (AEs) – type, grade, date of occurrence, duration, resolution - toxicity management (medication, dose modification) and outcome were collected.
Results
A total of 243 pts (43,6% hematologic, 23,1% non-Hodgkin lymphoma (NHL), 33,3% solid tumors excluding NHL) were included in 15 epidrug monotherapy P1 trials between Jan 2010 and March 2017; 62% were male; median age was 65 yo and median treatment duration was 119 days; 1980 treatment cycles and 335 AEs were analysed: 118 (35%) (64 G1-2; 54 G3-4) and 217 (65%) (114 G1-2; 103 G3-4) AEs occurred during and after cycle 1 (C1; DLT period), respectively; 58% of AEs were hematological toxicities. The risk of G3-4 toxicity for hematologic pts was 15% and 11% during and after C1 respectively, and was 12% and 18% for solid tumors excluding NHL, and was 29% and 24% for pts with NHL. DLT occurred in 10 pts (4%). Dose reduction occurred in 15% of pts, after a median duration of 21 treatment days. Temporary and definitive treatment interruption for toxicity occurred in 21% and 9% of pts, respectively; 87% of these occurred after C1.
Conclusions
In P1 trials of epidrugs, 65% of high-grade AEs occur after cycle 1 and 42% are non-haematological toxicities. More pts with NHL than pts with solid tumors (excluding NHL) or hematological malignancies present their first severe AE during C1. The dose recommendation process may require fine-tuning according to each pt population. Like molecularly targeted or immune therapies, epidrugs have distinct toxicity profile requiring specific attention in their development process.
Legal entity responsible for the study
Gustave Roussy Institut.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
11P - Photosensitizer-based multimodal nanocomposites as a theranostic agent for near infrared (NIR)-guided cancer-targeting synergistic chemo-phototherapy (ID 85)
- T. Ponraj
- T. Ponraj
- R. Vivek
- M. Paulpandi1
- K. Vimala
- A. Vasanthakumar
- S. Kannan
Abstract
Background
Many therapeutic methods existing for conventional cancer therapy have not been successful in achieving ideal outcomes or have noticeable side effects from off-targeting cytotoxicity. The photosensitizer-based cancer treatment approach has attracted great attention. Chemotherapy (CT), photodynamic therapy (PDT), and photothermal therapy (PTT), called combination treatments. In a single system could be potential solutions to address the above mentioned adverse effects in conventional therapy. Multimodal nanocomposites (NCs) are being used to achieve with innovative and noninvasive enhanced targeting synergistic anticancer phototherapy.
Methods
We prepared spherical-like titanium dioxide nanoparticles TiO2NPs by the water in oil emulsification method, obtaining a novel theranostic nanocomplex FA-ICG-Qtn@PVPylated-TiO2NPs. Nanocomplex (NCs) were characterized by various physicochemical techniques including UV via spectroscopy, TEM, DLS, FTIR, MTT, AO/EtBr, DAPI, cell cycle arrest, ROS, mitochondrial membrane potential loss, Western blot, RT-PCR, Histopathology, and immunohistochemistry. Studies were performed both in vitro/in vivo.
Results
The resulting TiO2NPs achieved high drug loading in combination with low leakage at physiological pH, and minimal toxicity toward healthy cells. To assist drug delivery, we have prepared FA-ICG-Qtn@PVPylated-TiO2NPs containing Qtn with high loading efficiency (35.2% w/w) as a novel drug delivery system. The NCs are taken up via FR endocytosis by MCF-7 cells and can generate intracellular reactive oxygen species (ROS) in order to increase mitochondrial membrane potential loss (MMPL) and enable release of cytochrome-c, followed by dysregulation of Bcl-xL into the cytosol and activation of caspase-7 to induce cancer cell apoptosis. These NCs can be utilized to improve cancer nanotherapy by induction of apoptosis in vitro. After intravenous in vivo direction of FA-ICG-Qtn@PVPylated-TiO2NPs NCs could significantly accumulate in the tumour-bearing Balb/c mice, and effectively inhibit the tumor growth after 808 nm laser irradiation as confirmed by the cancer cell killing studies in vivo.
Conclusions
The present thermal/pH-coupling controlled and targeted drug delivery system paves the way for the next generation of nanotherapeutics working toward a potential proficient targeted anticancer treatment.
Legal entity responsible for the study
Department of Zoology, Bharathiar University, Coimbatore.
Funding
Has not received any funding.
Disclosure
C. Massard: Consultant/Advisory fees: Amgen, Astellas, Astra Zeneca, Bayer, BeiGene, BMS, Celgene, Debiopharm, Genentech, Ipsen, Janssen, Lilly, MedImmune, Novartis, Pfizer, Roche, Sanofi, Orion; Principal/sub-Investigator of Clinical Trials: Aduro Biotech, Agios Pharmaceuticals, Amgen, Argen-X Bvba, Arno Therapeutics, Astex Pharmaceuticals, Astra Zeneca, Aveo, Bayer Healthcare Ag, Bbb Technologies Bv, Beigene, Bioalliance Pharma, Biontech Ag, Blueprint Medicines, Boehringer Ingelheim, Bristol Myers Squibb, Ca, Celgene Corporation, Chugai Pharmaceutical Co., Clovis Oncology, Daiichi Sankyo, Debiopharm S.A., Eisai, Exelixis, Forma, Gamamabs, Genentech, Inc., Gilead Sciences, Inc, Glaxosmithkline, Glenmark Pharmaceuticals, H3 Biomedicine, Inc, Hoffmann La Roche Ag, Incyte Corporation, Innate Pharma, Iris Servier, Janssen, Kura Oncology, Kyowa Kirin Pharm, Lilly, Loxo Oncology, Lytix Biopharma As, Medimmune, Menarini Ricerche, Merck Sharp & Dohme Chibret, Merrimack Pharmaceuticals, Merus, Millennium Pharmaceuticals, Nanobiotix, Nektar Therapeutics, Novartis Pharma, Octimet Oncology Nv, Oncoethix, Oncomed, Oncopeptides, Onyx Therapeutics, Orion Pharma, Oryzon Genomics, Pfizer, Pharma Mar, Pierre Fabre, Rigontec Gmbh, Roche, Sanofi Aventis, Sierra Oncology, Taiho Pharma, Tesaro, Inc, Tioma Therapeutics, Inc., Xencor; Research Grants: Astrazeneca, BMS, Boehringer Ingelheim, Janssen Cilag, Merck, Novartis, Pfizer, Roche, Sanofi; Non-financial support (drug supplied): Astrazeneca, Bayer, BMS, Boringher Ingelheim, Johnson & Johnson, Lilly, Medimmune, Merck, NH TherAGuiX, Pfizer, Roche. All other authors have declared no conflicts of interest.
12P - Targeting HIF1α/AP1 in hypoxia by novel 7-amino-6-halogeno-3-phenylquinoxaline-2-carbonitrile 1,4-dioxides (ID 140)
- A. Scherbakov
- A. Scherbakov
- G. Buravchenko
- L. Dezhenkova
- A. Shchekotikhin
Abstract
Background
HIF-1α and AP1 play important roles in hypoxia and activate anti-apoptotic pathways in tumor cells. No dual HIF-1α/AP1 inhibitors currently exist, so targeting these transcriptional factors is promising way to modulate hypoxia signaling in cancer cells. Aim of the study was obtaining and biological evaluation of hypoxia-selective 7-amino-6-halogen-substituted derivatives starting from 6,7-dihalogeno-3-phenylquinoxaline-2-carbonitrile 1,4-dioxides.
Methods
A series of 7-amino-6-halogeno-3-phenylquinoxaline-2-carbonitrile 1,4-dioxides was synthesized. Cancer cell lines were purchased from ATCC. The cytotoxic activity of compounds was evaluated in normoxia (21%O2) and hypoxia (1%O2). The cytotoxicity was assessed by MTT test (72 h growth with compounds). HIF-1α and AP1 activity was assessed by reporter analysis.
Results
Synthesis of 7-amino-6-halogen- substituted derivatives starting from 6,7-dihalogeno-3-phenylquinoxaline-2-carbonitrile 1,4-dioxides was carried out. A series was characterized by good solubility in water. Antiproliferative activity was evaluated in vitro on a panel of cancer cell lines including multidrug resistance variants. Novel synthesized compounds demonstrated higher hypoxia selectivity and cytotoxicity compared with tirapazamine. Some of the 7-amino-6-halogeno derivatives were 10-20-fold more potent than the reference drug. Selected 7-amino-6-halogeno derivatives LCTA-2425 and LCTA-2711 inhibited breast cancer cells growth in hypoxia at concentrations lower than 0.6 µM. Compounds LCTA-2711 and LCTA-2425 showed inhibitory effects on HIF-1α- and AP1-dependent luciferase activity, when tirapazamine revealed no potency to block these factors in MCF-7 breast cancer cells under hypoxic conditions.
Conclusions
A series of 7-amino-6-halogeno-3-phenylquinoxaline-2-carbonitrile 1,4-dioxides were more potent than reference drug tirapazamine in all tested cell lines and demonstrated high selectivity in hypoxia. Selected 7-amino-6-halogeno derivatives showed dual inhibitory activity against HIF-1α and AP1 factors, regulating anti-apoptotic pathways in hypoxia. RFBR grants 18-53-34005 (chemistry), 18-015-00422 (biology).
Legal entity responsible for the study
Alexander M. Scherbakov.
Funding
Russian Foundation for Basic Research, Grants 18-53-34005 (Chemistry) and 18-015-00422 (Biology).
Disclosure
All authors have declared no conflicts of interest.
13P - Phosphoproteome and gene expression profiling of ALK inhibition in neuroblastoma cell lines reveals conserved oncogenic pathways (ID 129)
- G. Umapathy
- G. Umapathy
- J. Van den Eynden
- D. Cervantes-Madrid
- J. Szydzik
- J. Guan
- R. Palmer
- B. Hallberg
Abstract
Background
Anaplastic lymphoma kinase (ALK) is a tyrosine kinase receptor that is a clinical target of major interest in cancer. Mutations and rearrangements in ALK trigger the activation of the encoded receptor and its downstream signaling pathways. ALK mutations have been identified in both familial and sporadic neuroblastoma cases as well as in 30 to 40% of relapses, which makes ALK a bona fide target in neuroblastoma therapy. Tyrosine kinase inhibitors (TKIs) that target ALK are currently in clinical use for the treatment of patients with ALK-positive non–small cell lung cancer. However, monotherapy with the ALK inhibitor crizotinib has been less encouraging in neuroblastoma patients with ALK alterations, raising the question of whether combinatorial therapy would be more effective.
Methods
In this study, we established both phosphoproteomic and gene expression profiles of ALK activity in neuroblastoma cells exposed to first- and third-generation ALK TKIs, to identify the underlying molecular mechanisms and identify relevant biomarkers, signaling networks, and new therapeutic targets.
Results
The phosphoproteomic analysis identified several conserved oncogenic downstream signaling pathways of ALK, similar to those involved in insulin receptor (INSR)/tropomyosin receptor kinase (TRK) and fibroblast growth factor receptor (FGFR) signaling. In addition, signaling events involved in feedback and cross-talk were identified, including modulation of DUSP (dual-specificity phosphatase) family phosphatases. Furthermore, from analysis of the RNA-seq data, several transcription factors were predicted and validated as responsive to ALK signaling, including members of the FOXO (forkhead box O) and ETS (E26 transformation-specific or E-twenty-six) transcription factor families.
Conclusions
Although neuroblastoma is a complex heterogeneous disease, this in-depth investigation of downstream targets of ALK signaling offers future avenues to pursue to inhibit ALK-driven neuroblastoma.
Legal entity responsible for the study
Bengt Hallberg.
Funding
Barncancerfonden.
Disclosure
All authors have declared no conflicts of interest.
14P - Butein inhibits solid tumors cell viability, colony, and tumor growth via STAT3 signaling pathway and enhance the anti-cancer effects of Frondoside-A and camptothecin (ID 190)
- S. Attoub
- S. Attoub
- S. Sulaiman
- K. Arafat
Abstract
Background
Despite the major recent advances in cancer management, cure of cancer remains a serious challenge.
Methods
In the current study, we investigated the impact of butein, a biologically active flavonoid, on the human cancer cell survival and colony growth in vitro, and on tumor growth in vivo, alone and in combination with Frondoside-A, a triterpenoid glycoside isolated from an Atlantic sea cucumber, and camptothecin.
Results
We demonstrate that butein causes a concentration- and time-dependent decrease in the viability of the lung cancer cells (A549 and LNM35), the breast cancer cells (MDA-MB-231 and T47D), and a decrease in their related colonies growth in vitro. Similarly, treatment with butein significantly decreased the growth of A549 and MDA-MB-231 xenografts in the chick embryo model in vivo (P < 0.01) without significant toxicity. To determine whether the inhibition of cell viability and tumor growth by butein is due to growth arrest or to cell death, we assessed the induction of apoptosis by measuring caspase-3 activity and PARP cleavage. The treatment of lung and breast cancer cells with butein induce caspase-3 activation leading to PARP inactivation in a concentration and time-dependent manner. More than 50% of lung cancers and 40% of breast cancers show constitutive activation of STAT3. The role of this transcription factor in cancer progression is now well established and its targeting in cancer therapy is a very promising and challenging option. We observed that butein treatment induce a concentration and time-dependent inhibition of STAT3 phosphorylation without any impact on total STAT3. We finally demonstrate that butein at the IC25 and IC50 concentration enhances the anti-cancer effect of Frondoside-A as well as the effect of camptothecin on lung and breast cancer cells in vitro.
Conclusions
These findings increase our confidence of the potential benefit of using butein as an anticancer agent for the treatment of solid tumors either alone, and/or in combination with Frondoside-A and camptothecin.
Legal entity responsible for the study
Samir Attoub.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
15P - ATM loss in NSCLC increases sensitivity to cisplatin and PARP inhibition (ID 191)
- D. Bebb
- D. Bebb
- L. Petersen
- J. Moore
- A. Elegbede
- S. Lees-Miller
Abstract
Background
Most patients with advanced NSCLC don’t receive guideline recommended treatment as their poor performance status makes them ineligible for platin-based treatment protocols. While tumour-specific loss of ATM in early-resected NSCLC is associated with poor survival, these patients derive increased benefit from adjuvant chemotherapy, including cisplatin. We have previously reported that ATM-deficient cell lines in MCL and gastric cancer show increased sensitivity to PARP inhibition, and recent studies have indicated cisplatin sensitivity arising from DNA damage repair deficiencies. Here we present preclinical data suggesting that lower doses of platin in combination with PARP inhibition may be an option in patients whose tumours exhibit ATM loss.
Methods
We identified ATM-deficient NSCLC cell lines by protein expression and activation in response to ionizing radiation. Cells were treated with cisplatin and PARP inhibitor (olaparib) alone or in combinations to determine sensitivity by clonogenic survival assay. ATM was knocked out in an ATM-proficient cell line by Cas9-CRISPR gene editing, and cells were analyzed for the effect of cisplatin and olaparib on cell cycle progression.
Results
ATM-deficient NSCLC cell lines were sensitive to both cisplatin and olaparib alone, and this effect was amplified when drugs were given in combination, even at lower doses of both. ATM signalling was activated in response to these drugs in ATM-proficient cells, however when ATM is knocked out the cells become more sensitive to either drug alone or in combination. Interestingly, apoptosis does not appear to increase in ATM-KO cells, but rather cells accumulate in G2 – particularly cells treated with olaparib.
Conclusions
Our results suggest that ATM loss is sufficient to sensitize NSCLC cells to combinations of cisplatin and olaparib. PARP inhibition may arrest cells in G2, and while cisplatin does not appear to push cells into an apoptotic state, cell death might be triggered via another mechanism. This suggests that NSCLC patients with ATM loss in their tumour may benefit from lower doses of platin and PARP inhibitors, a combination that may allow increased uptake of palliative systemic treatment including the addition of immunotherapy.
Legal entity responsible for the study
D. Gwyn Bebb.
Funding
Glans-Look Lung Cancer Research.
Disclosure
All authors have declared no conflicts of interest.
16P - Inhibition of PDE4 sensitizes drug resistant NSCLC to TKI therapy (ID 189)
- S. Mukherjee
- S. Mukherjee
- D. Suresh
- A. Upendran
- R. Kannan
Abstract
Background
NSCLC patients undergoing tyrosine kinase inhibitor (TKI) therapy often develop resistance (9-12 months) resulting in low median survival (10-14 months) among stage IV patients. Studies showed that, in some cases, the resistance can be attributed to upregulation of pro-survival PI3K-Akt pathway. Indeed, EGFR-mutant patients with elevated levels of phospho-Akt have shown poor therapeutic response and the levels of p-Akt are increased upon prolonged EGFR TK treatment. In addition, several mechanistic studies attribute increased phospho-Akt (p-Akt) levels in tumor as one of the reasons for drug resistance. In an independent study, researchers have shown that suppression of phosphorylation of Akt can be achieved by inhibition of Phosphodiesterase- 4(PDE4) and in turn activate luminal apoptosis. Therefore, we hypothesized that PDE4 inhibition would sensitize drug resistant NSCLC to tyrosine kinase inhibitor therapy by abrogating the PI3K-Akt pathway.
Methods
TK resistant cell lines along with controls were used for the study. First generation TKIs, Dasatinib, Erlotinib and Gefitinib were used to study the efficacy of TKI. Roflumilast, a drug already used in chronic obstructive pulmonary disorder (COPD), was used as the PDE4 inhibitor.
Results
Inhibition of PDE4 followed by treatment with TKIs showed remarkable decrease in IC50values, compared to either PDE4 inhibition or TK inhibition. Upon PDE4 inhibition, efficacy of TKIs is found to be increased several folds compared to individual inhibitors. Cells showed no signs toxicity to the PDE4 inhibitor at the dose levels used, thus making the inhibitor itself absolutely nontoxic at this treatment dose.
Conclusions
Our results suggest that PDE4 inhibition is a potential way to reverse TKI resistance and also to improve TKI therapy in patients with high levels of p-Akt.
Legal entity responsible for the study
University of Missouri - Columbia, Missouri, USA.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
17P - microRNA-16-5p enhances radiosensitivity through modulating cyclin D1/E1–pRb–E2F1 pathway in prostate cancer cells (ID 169)
- L. Gan
- F. Wang
Abstract
Background
Prostate cancer (CaP) was the second most common cancer in men worldwide in 2012, and radiation therapy is one of the most common definitive treatment options for localized CaP. However, radioresistance is a major challenge for current radiotherapy, accumulating evidence suggests microRNAs (miRNAs), as an important regulator in cellular ionizing radiation (IR) responses, are closely correlated with radiosensitivity in many cancers.
Methods
We performed human miRNA probe hybridization chip analysis to identify the expression profile of miRNAs in CaP cells exposed to IR, and then we analysed the cell proliferation, cell viability, and cell cycle after transfection of miR‐16‐5p into the CaP cells. Analysis of the cyclin D1/E1–pRb–E2F1 pathway related proteins were performed by western blotting.
Results
microRNA- 16-5p (miR-16-5p) is significantly upregulated in CaP LNCaP cells following IR and can enhance radiosensitivity through modulating the cyclin D1/E1–pRb–E2F1 pathway. Overexpression of miR-16-5p suppressed cell proliferation, reduced cell viability, and induced cell cycle arrest at G0/G1 phase, resulting in enhanced radiosensitivity in LNCaP cells. Additionally, miR-16-5p specifically targeted the cyclin D1/E1-3′-UTR in LNCaP cells and affected the expression of cyclin D1/E1 at both mRNA and protein levels.
Conclusions
miR-16-5p enhanced radiosensitivity of CaP cells, the mechanism may be through modulating the cyclin D1/cyclin E1/pRb/E2F1 pathway to cause cell cycle arrest at G0/G1 phase. These findings provided new insight into the correlation between miR‐16‐5p, cell cycle arrest, and radiosensitivity in CaP, revealed a previously unrecognized function of miR‐16‐5p–cyclin D1/E1–pRb–E2F1 regulation in response to IR and may offer an alternative therapy to improve the efficiency of conventional radiotherapy.
Legal entity responsible for the study
Institute of Modern Physics, Chinese Academy of Sciences.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
18P - Choline transporter-like protein 1 (CTL1/SLC44A1) is a therapeutic target molecule for prostate cancer therapy (ID 115)
- M. Inazu
- M. Inazu
- I. Saiki
- H. Uchino
- T. Yamanaka
Abstract
Background
Prostate cancer is one of the most common types of cancer in men. Choline is an essential component of cell membrane phospholipids and is metabolized and internalized into cells by choline kinase, an enzyme that is overexpressed in certain tumors, such as prostate cancer. Two choline tracers are available for clinical use, which are labeled either with 11C-choline or with 18F-choline. These choline PET tracers that target cell membrane metabolism have influenced prostate cancer imaging, particularly in biochemical relapse, and are therefore FDA approved for use in patients with recurrent disease. However, the uptake system for choline and the functional expression of choline transporters in prostate cancer are not totally understood.
Methods
We examined [3H]choline uptake in the prostate cancer cell line LNCaP, which depends on androgen. Cells were cultured in RPMI 1640 medium supplemented with 10 % fetal bovine serum and grown at 37 °C in 5% CO2. The CellTiter-Glo Luminescent Cell Viability Assay is a homogeneous method of determining the number of viable cells. The Caspase-Glo 3/7 assay reagent was used for caspase detection in treated cells.
Results
[3H]Choline uptake is mediated by a single Na+-independent and intermediate-affinity transport system. Choline transporter-like protein 1 (CTL1) and CTL2 mRNA are highly expressed. CTL1 and CTL2 immunoreactivity were recognized in the plasma membrane and intracellular compartments, respectively. The anticancer drugs, flutamide, and bicalutamide inhibited cell viability and [3H]choline uptake in a concentration-dependent manner. The correlations between the effect of both anticancer drugs for cell viability and [3H]choline uptake were significant. The caspase-3/7 activity significantly increased by flutamide and bicalutamide. Furthermore, both flutamide and bicalutamide decreased the expression level of CTL1 in LNCaP cells.
Conclusions
These results suggest that CTL1 are functionally expressed in prostate cancer cells and are also involved in abnormal proliferation. Identification of this CTL1-mediated choline transport system provides a potential new target for prostate cancer therapy.
Legal entity responsible for the study
Tokyo Medical University.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.