bluuebunny/crossref_metadata_2025 huggingface dataset:
Pharmacogenetics of a PARP inhibitor ABT-888 metabolic pathway
Authors: Li J. , Sha X. , LoRusso P.
Published: August 2020

e14556

Background: Poly(ADP-ribose) polymerase (PARP) is essential for single-stranded DNA break repair and repair of DNA damage can lead to radio- and chemo-resistance. Thus, inhibition of PARP activity can sensitize cells to cytotoxic therapies. ABT-888 is a potent, orally bioavailable PARP inhibitor. Preclinical studies suggest that ABT-888 potentiates multiple cytotoxic agents and its efficacy is correlated with plasma/tumor drug concentrations. The objective of this study was to determine the pharmacogenetic effect of genetic variants in the ABT-888 metabolic pathway, with the aim to better understand molecular basis of the variation in ABT-888 pharmacokinetics (PK) and therapeutic outcome. Methods: The major enzymes responsible for ABT-888 metabolism were identified by in vitro metabolism studies with specific recombinant human cytochrome P450 (CYP) enzymes. The functional significance of genetic variants of the identified enzymes was assessed by examining ABT-888 metabolic kinetics by candidate variant enzymes and microsomes. The association of the functional significant genetic variants with the PK and clinical outcome is being evaluated in the context of an ongoing phase I trial in which ABT-888 is administered in combination with irinotecan in patients with advanced solid tumors. Results: ABT-888 was metabolized predominantly by human CYP2D6, to a less extent by CYP1A1, and to a negligible extent by CYP1A2, 2C9, 2C19, 3A4, and 3A5. CYP2D6*10 exhibited markedly reduced catalytic capability in ABT-888 overall metabolism and the metabolite (A-925088) formation, with in vitro maximum clearance being 31% and 5.3%, respectively, of that estimated from the wild-type CYP2D6. In human liver microsomes carrying homozygous CYP2D6*4, the rates of parent drug disappearance and metabolite formation were significantly lower than those observed in the microsomes carrying wild-type CYP2D6, P < 0.05. Conclusions: CYP2D6 is the predominant enzyme responsible for the hepatic metabolism of ABT-888. Common allelic variants CYP2D6*10 and *4 are associated with significantly reduced metabolic activity towards ABT-888. CYP2D6 polymorphisms may influence the PK and therapeutic outcome of ABT-888. Its clinical relevance remains to be determined.

No significant financial relationships to disclose.
Predicting response to irinotecan/5-fluorouracil (5-FU) chemotherapy for advanced colorectal cancer based on gene expression in primary tumour
Authors: Coyle V. , Allen W. , Jithesh P. , McManus D. , Stevenson M. , Harte R. , Eatock M. , Wilson R. , Johnston P.
Published: August 2020

e14558

Background: Despite improvements in the treatment of advanced colorectal cancer (CRC), there remains a subset of patients who fail to benefit from chemotherapy. The identification of predictive response markers has been limited by the relative scarcity of metastatic tumour samples for molecular analysis, prompting a need to consider surrogate models for generation of predictive markers. Methods: We performed gene expression profiling of archived formalin fixed paraffin-embedded (FFPE) colorectal primary tumours (dating from 2001–2007) from 40 patients who received irinotecan/5-FU chemotherapy as first line treatment for advanced disease. Patients were classified as responders/non-responders based on radiological response. Gene expression profiling was performed using the Almac Diagnostics Colorectal Disease Specific Array (DSA). Data was analysed using Genespring GX v7.3. Principal Components Analysis (PCA) was used to separate responding and non-responding patients based on the tumour- derived expression data. Predictive classifiers were constructed using several class prediction methods. The performance of the classifiers was assessed by leave-one-out cross-validation. Results: 37 samples passed data QC assessments for inclusion in predictive analysis. PCA using genes passing a t-test and 1.5-fold change filter demonstrated clear separation between responding and non-responding patients. Predictive modelling using the k-nearest neighbour and Support Vector Machine (SVM) algorithms with Fishers exact test as feature selection method each generated seven different predictive classifiers containing 5 to 35 genes; these had an average predictive accuracy of 80%. Predictive modelling of this dataset is ongoing and these encouraging initial results will be extended to a larger patient cohort. Conclusions: DNA microarray profiling has been used to generate gene signatures predictive of response to irinotecan/5-FU therapy in advanced CRC; importantly, these predictive signatures have been generated from FFPE colorectal primary tumour facilitating their independent validation in large patient cohorts and potential clinical implementation in the event of successful validation.

[Table: see text]
UGT1A1,A7 and A9 genotyping and pharmacokinetics of irinotecan-containing chemotherapy in patients with advanced cancer
Authors: Valenzuela B. , Nalda R. , Duart M. , Escudero V. , Perez-Ruixo J. , Martinez-Navarro E. , Rebollo J. , Gonzalez R. , Brugarolas A.
Published: August 2020

e14563

Background: To the best of our knowledge only one previous report in asian lung cancer patients (pts) assesed UGT1A1, A7 and A9 genotypes along with irinotecan pharmacokinetics (Han et al. JCO 2006; 24: 2237–44). We set out to evaluate UGT1A1, A7 and A9 genotypes in caucasian cancer patients and their relationship with both irinotecan toxicity and irinotecan pharmacokinetics. Methods: UGT1A1, A7 and A9 genotypes were obtained from blood genomic DNA by direct sequencing. The area under the time-concentration curve (AUC) of SN-38 and SN-38G were calculated. The ratio between these AUCs (AUC SN-38G /AUC SN-38) was also calculated. Associations between pharmacokinetics parameters and the UGT1A genotypes were assessed by univariate analysis. Toxicity was collected using standard NCI grading criteria. Statistical correlation between presence of grade III and IV toxicity and UGT1A1,A7 and A9 genotypes was done by Pearson's Chi square. At least 80 patients (with both genotype and pharmacokinetics) are needed to achieve enough statistical power. Results: At the time of writing this abstract, complete genotyping and toxicity data from 59 patients were available. Sex (females 17, males 42). Median age 60 (range 25–88). Pathology (no. pts): lung (26), colon (17), others (16). 21 pts. (35.59%) had received previous chemotherapy. All but 5 pts received doses of irinotecan between 120 and 150 mg/m2. Median no. of cycles 6 (range 1–15). The frequencies of the different UGT1A1, A7 and A9 genotypes are similar to those previously reported. At least one episode of grade III or IV leukopenia was present in 19 pts. (32.2%), and grade III diarrea in 11 pts (18.6%). No statistically significant correlation was found between presence of leukopenia grades III and IV, and the genotypes UGT1A1,A7, and A9 (P=0.687, P=0.156 and P=0.476, respectively). Diarrea grade III was not statistically significantly associated with UGT1A1 (P=0.318), A7 (P=0.318) and A9 (P=0.158). 21 out of 59 pts. had pharmacokinetics (PK) data available. In genotype-PK association analysis, UGT1A1,A7 and A9 were not statistically associated with AUC SN-38G / AUC SN-38 ratios (P=0.844, P=0.911, P=0.431, respectively). Conclusions: Patients are still being accrued to achieve the targeted size.

No significant financial relationships to disclose.
Using epigenetic reprogramming to target triple-negative breast cancer
Authors: Sharma D. , Knight B. B. , Yacoub R. , Liu T. , Taliaferro-Smith L. , Nagalingam A. , O'Regan R. M.
Published: August 2020

e14565

Background: The outcome for patients with breast cancer has been significantly improved by the use of targeted agents. The prognosis of triple negative (TN) breast cancers, which do not express hormone receptors (ER, PR) or Her2, is poor, because of an aggressive clinical course and lack of targeted therapeutic agents. Epigenetic silencing of specific genes has been observed in breast cancer and some of these genes are more important due to available targeted therapies such as ER. Since all endocrine therapies are designed to block ER function in some way, the identification of new therapies or strategies that could sensitize TN breast cancers to existing endocrine therapy could provide a revolutionary means of treating this aggressive subtype of cancer Methods: We examined the efficacy of combined treatment of HDAC inhibitor LBH589 and DNMT inhibitor decitabine to regenerate ER and PR in TN breast cancer cells using RT-PCR and immunoblotting. Changes in growth and proliferation of TN breast cancer cells in response to LBH589 and decitabine treatment were determined by XTT, BrdU incorporation and colony formation assay. Changes in apoptotic proteins were determined by western blotting. Athymic nude mice were used to establish pre-clinical models for TN breast cancer cells and effectiveness of combined treatment of LBH589 and decitabine was determined. Tumors biopsies were analyzed for ER and PR re-expression by western blot analysis and immunohistochemistry at the end of the treatment. Results: Combined treatment of LBH589 and decitabine resulted in re-expression of ER and PR in TN breast cancers in vitro and in vivo. Although re-expression of ER and PR were noted following LBH589 treatment alone, re-expression was more robust with the combination. TN breast cancer cells showing re-expressed ER can be targeted with tamoxifen. Tamoxifen inhibits growth of TN breast cancer cells re- expressing ER by triggering apoptosis. Conclusions: The importance of epigenetic events such as DNA methylation and HDAC inhibition in tumor progression is becoming increasingly evident. A trial evaluating the ability of LBH589 and decitabine to re- express ER, which can then be targeted by tamoxifen, is planned in patients with metastatic TN breast cancer.

No significant financial relationships to disclose.
Cutaneous genital complications of antiangiogenic agents
Authors: Mateus C. , Massard C. , Tomasic G. , Wechsler J. , Boige V. , Le Cesne A. , Soria J. C. , Escudier B. , Robert C.
Published: August 2020

e14568

Background: Multikinase inhibitors targeting VEGFR, i.e. sorafenib and sunitinib are associated with various cutaneous side effects (1). Five cases of scrotal skin lesions were recently reported in male patients treated with sunitinib (2). Our observations of 8 patients presenting with genital inflammatory lesions during various anti-VEGFR therapies show that this side effect is linked to VEGFR blockade and not specifically to sunitinib and that it can also occur in women. Results: Six men and two women were seen for a genital eruption. They were treated with sorafenib (3 pts), sunitinib (5 pts), and a new pan-HER and VEGFR inhibitor (BMS 514, EVRI) (1 pt) for renal cell cancer (4 pts), hepatocellular carcinoma (2 pts), lung cancer (1 pt) and sarcoma (1 pt). Genital lesions occurred during the first six weeks of treatment. They appeared as a painful erythematous and squamous inguinal, intergluteal, and perianal rash rapidly involving all genital areas in 4 patients. Lesions became erosive in 3 cases. Four men presented more limited, pruriginous and lichenoid penile papules which were associated with a genital erythema for 3 of them. In one patient, penile inflammation resulted in a phimosis. One patient successively treated with sunitinib, sorafenib and once again with sunitinib experienced genital side effects with both agents. Patients taking sequential sunitinib treatment reported symptoms improvement during treatment interruptions and recurrences during the weeks on therapy. Microbiological samples were negative. Pathology of erythematous and squamous lesions showed a psoriasiform or a lichenoid aspect. Topical steroids were efficient for 5 patients but 3 patients had to interrupt anti-VEGF therapy because of their genital rash. Conclusions: Polymorphous genital inflammatory rash is a new skin side effect that can be associated with any cancer therapies targeting VEGFR in men and in women. Its frequency is unknown and probably underestimated because many patients might not report this side effect and its mechanism is still obscure. Physicians should be aware of this side effect and should inquire as to whether the patients have noticed such symptoms in order to avoid worsening thereof by symptomatic measures.

No significant financial relationships to disclose.
Gastrin-releasing peptide receptors in the tumor vascular bed of various human cancers: high incidence in urinary tract cancers
Authors: Fleischmann A. M. , Waser B. , Reubi J. C.
Published: August 2020

e14575

Background: Tumoral Gastrin-releasing peptide (GRP) receptors are potential targets for diagnosis and therapy using radiolabeled or cytotoxic GRP analogs. GRP-receptor overexpression has been detected in cancer cells and, more recently, also in the vascular bed of selected tumors. More information on vascular GRP-receptors in cancer is required to asses their potential for vascular targeting applications. Methods: Frequent human cancers from the breast (n=134), lung (n=57), prostate (n=50), kidney (n=32), colon (n=46), urinary tract (n=26) and biliary tract (n=23) were analyzed using in vitro GRP-receptor autoradiography on tissue sections with the 125I-[Tyr4]-bombesin radioligand and/or the universal radioligand 125I-[D-Tyr6, ß-Ala11, Phe13, Nle14]-bombesin(6–14). GRP-receptor expressing tumoral vessels were evaluated in each tumor group for prevalence, quantity (vascular score) and GRP-receptor density. Results: Prevalence of vascular GRP-receptors is variable, ranging from 13% (prostate cancer) to 92% (urinary tract cancer). Different tumor-types within a given site may have divergent prevalence of vascular GRP-receptors (e.g. lung: small cell cancer: 0%; adenocarcinoma: 59%; squamous carcinoma: 83%). Also the vascular score varies widely, with highest score in urinary tract cancer (1.69), moderate scores in lung (0.91), colon (0.88), kidney (0.84) and biliary tract (0.69) cancers and low scores in breast (0.39) and prostate (0.14) cancers. Vascular GRP-receptors are expressed in the muscular vessel wall in moderate to high densities. Normal non- neoplastic control tissues from these organs lack vascular GRP-receptors. Conclusions: Tumoral vessels in all evaluated sites overexpress GRP-receptors, suggesting a major biological function of GRP-receptors in the tumor vascular bed. Vascular GRP-receptor expression varies between the tumor-types indicating tumor-specific mechanisms in their regulation. Urinary tract cancers express vascular GRP-receptors so abundantly, that they are promising candidates for vascular targeting applications.

No significant financial relationships to disclose.
Can [F-18]FDG PET imaging predict early response to chemotherapy in breast cancer patients?
Authors: John C. S. , Madabushi R. , Farah C. , Lubas C. , Williams G.
Published: August 2020

e14577

Background: The purpose of this study was to perform a meta-analysis of literature data and see if [F-18]FDG and PET imaging can be used to predict the early response to chemotherapy based upon the measure of standard uptake value (SUV) or drug uptake ratio (DUR; a measure of glycolytic index) in breast cancer patients. This intervention may identify the responders for continued therapy or identify the non- responders for change of therapy. Methods: A literature search determined the number of studies that used PET-FDG imaging to monitor the response of various chemotherapies in breast cancer patients. A total of nine studies have been reviewed that used SUV/DUR as a measure of glycolytic activity of the primary tumors. The percent decrease of SUV over baseline was determined for chemotherapy cycle 1 and for subsequent cycles. A paired t-test was performed to see the statistical significance of the SUV decrease. Results: Five (n=158) studies presented the data in % mean reduction in SUV and four (n=59) studies presented SUV values for the individual patient. The average decrease in SUV in responders were 29% and 51% after first and second cycle, respectively. The non responders did not show significant change in SUV as compared to responders. Conclusion: The preliminary data mining and analysis strongly implies that PET imaging using [F-18]FDG may be used to monitor the progress of chemotherapy in breast cancer patients. This study was supported by a grant from OWH, FDA. The results do not represent official FDA position.

No significant financial relationships to disclose.
The antitumor effects of OSU-HDAC42, a novel histone deacetylase inhibitor, in HER-2-positive breast cancer
Authors: Weng S. , Wu E. , Kulp S. K. , Wang D. , Chen C. , Yee L. D.
Published: August 2020

e14587

Background: Elevated HER-2/neu expression in primary breast tumors is associated with frequent relapse and poor prognosis. For this reason, HER-2/neu has been actively pursued as a target for novel therapeutic agents. Histone deacetylase inhibitors (HDACi), a new class of antitumor drugs, can downregulate HER2 through hyperacetylation of heat shock protein 90 (hsp90), an important ATP-dependent chaperone that mediates the stability and maturation of a variety of important oncogenic proteins, including HER2, Akt and ERα. In this study, we assess the effects of OSU-HDAC42, a novel orally bioavailable phenylbutyrate-based HDAC inhibitor, on hsp90 and HER2 downregulation. Methods: OSU-HDAC42 was tested for effects on the human breast cancer cell lines BT474, SKBR3, MDA-MB-231 and MCF-7. Assays of cell viability, cell cycle, apoptosis, HER2 expression, phosphorylation, and hsp90 acetylation were performed. Tumor growth was assessed in an orthotopic HER2+ mammary tumor model, using diets ± OSU-HDAC42. Results: SKBR3 (HER2+, ERα-) was the most susceptible to the antiproliferative effects of OSU-HDAC42 after 72 hours of treatment (IC50 = 0.025 μmol/L), followed by BT474 (HER2+, ERα+), MCF-7 (HER2-, ERα+) and MDA-MB-231 (HER2-, ERα-) cells with IC50 values calculated at 0.16, 0.19 and 0.2 μmol/L, respectively, which correlated with the level of inhibition of Hsp90 client protein expression (HER2, Akt). OSU-HDAC42 yields 43- or 65- fold greater cell killing than suberoylanilide hydroxamic acid (SAHA; vorinostat) or MS-275, respectively, and more potently suppresses the levels of Hsp90 client proteins (HER2, ERα and Akt) and induction of apoptosis in HER2+ breast cancer cells. In vivo administration of OSU-HDAC42 resulted in reductions of 76% and 82% in NT5 (HER2+,ER-) tumor mass and volume, respectively, concomitant with tubulin hyperacetylation, increased PARP cleavage, and decreased HER2 levels in OSU-HDAC42 treated mouse tumors. Conclusions: OSU-HDAC42 is a potent inhibitor of HER2+ breast cancer, mediated in part through hsp90 downregulation. As an orally bioavailable HDAC inhibitor with greater potency than other clinically available HDACi agents, OSU- HDAC42 warrants evaluation in clinical trials as a novel therapy for HER2+ breast cancer.

[Table: see text]
Single nucleotide polymorphisms of TSER, ATM, RecQ1 genes association with survival in pancrease cancer
Authors: Weekes C. , Nallapareddy S. , Jimeno A. , Hidalgo M. , Laheru D. , Rudek M. A. , Baker S. , Redlinger C. , Murphy K. , Messersmith W.
Published: August 2020

e14590

Background: Pancreatic cancer (PaCa) is the 4th leading cause of cancer-related mortality in the U.S . We tried to determine whether ATM, RecQ1 gene polymorphisms correlate with gemcitabine (G) and TSER gene polymorphism with capecitabine (C) response and over all survival(OS). We also tested the hypothesis that PaCa pts homozygous for the S/S variant of the TSER will have a higher 6-month survival with C compared to historical controls. TS expression is regulated by a polymorphism in the TSER and has been shown that pts with S/S variant have high response rate and increased toxicity in colon cancer pts. ATM and recQ1 genes are involved with DNA damage response and repair and correlate with G response. Methods: DNA isolated from peripheral blood samples in 82 pts with Stage IV pancreatic cancer was tested for the TSER, ATM and RecQ1 gene polymorphisms. All patients were treated with G 1,000mg/m2 wkly for 3/4 wks. Pts homozygous for the S/S variant were treated with C, 2,000 mg/m2/day for 14 /21days. Pts were evaluated for response to therapy according to the RECIST. Results: 16 pts (19.5%) were positive for S/S variant of TSER, but only 4 (4.8%) were treated. The reasons for declining treatment were geographic, logistic or progression issues. Only 1 pt was evaluable, receiving at least 3 cycles of C . All pts needed dose reductions due to toxicities. Grade 3 hand foot syndrome, diarrhea and vomiting were dose limiting toxicities. No complete or partial responses were seen. The pt who received 3 cycles came off study due to progressive disease and the other 3 pts came of the study due to toxicities. TSER polymorphism was correlated to OS and only S/S variant was significant with a trend towards improved OS by log rank test and Kaplan Meier plot. ATM and RecQ1 gene polymorphisms subtypes did not correlate with G response and OS ( not statistically significant). Conclusions: Our study represents an initial effort to apply pharmacogenetics to PaCa therapy. 19.5% of pts had the S/S variant of the TSER polymorphism, but only 4.8% enrolled. C administration was associated with excess toxicity. The toxicities observed in this study appear to outweigh the benefit of using C in this pt population. There is no correlation between ATM and RecQ1 genotypes with OS. However the sample size is too small to draw conclusions.

[Table: see text]
Population pharmacokinetics of CNTO 95, a human anti-αv integrin antibody, in patients with solid tumors
Authors: Ling J. , Zhang Y. , Hu C. , Jiao T. , Lang Z. , Foster B. , Marini J. , Zhong B. , Puchalski T. , Zhou H.
Published: August 2020

e14593

Background: CNTO 95 is a human anti-αv integrin antibody. The dose-dependent antitumor effect of CNTO 95 has been demonstrated in multiple preclinical studies. The objective of these analyses was to characterize the population pharmacokinetics (PPK) in solid tumor cancer patients treated with CNTO 95 with and without dacarbazine. Methods: Approximately 140 patients with solid tumors from two phase I and one phase II studies were included in this analysis. CNTO 95 was administered via intravenous infusion, with 11 different regimens ranging from 0.1 to 20 mg/kg every 1–4 weeks. Serum CNTO 95 concentrations were determined using a validated enzyme-linked immunosorbent assay. Serum CNTO 95 concentration data were analyzed using noncompartmental analysis (NCA) and a PPK approach. Results: The NCA results indicated that total clearance of CNTO 95 decreased as the dose of CNTO95 increased and approached saturation at 10 mg/kg. Based on the NONMEM analysis, data were best described by a 2-compartment model with dual clearance pathways (linear and nonlinear elimination). The nonlinear elimination process is likely due to the receptor-mediated clearance. Mean estimates of central volume, peripheral compartment volume, intercompartmental clearance and linear clearance, as well as an additional nonlinear clearance, were in agreement with antibodies targeting membrane-bound receptors. No differences in the PPK of CNTO 95 were found in patients treated with and without co-administered dacarbazine. Interindividual variability was moderate (<50%). Conclusions: A PPK model could adequately describe serum CNTO 95 concentration-time profiles. Extensions of this model can be used to assist in the selection of doses in diverse oncology patient populations.

[Table: see text]
Ultra-sensitive detection of biomarkers and applications in pharmaceutical discovery and development. Example application to rat cardiac troponin I assay via nanoparticle probes
Authors: Bao P. , Lubben T. , Holzman T.
Published: August 2020

e14594

Although specific to heart, rat cardiac troponin I (cTnI) is an example of an important biomarker for assessing drug-induced cardiotoxicity in animal models used in various phases of drug discovery and development. Current commercially available assays can only detect 10 ∼ 100 pg/mL in serum at the lowest limits. To improve the sensitivity of rat cTnI assay, we have developed a generically applicable, microarray based nano-probe test. Our rat cTnI assay algorithm uses a multi-step robotic process, which relies on non- isotropically oriented antibodies on functionalized glass as multiplexed microarrays to capture cTnI from serum. Functionalized, 130 angstrom diameter gold nano-probes (measured by static light scattering, 5 nm S.D.) also bind to the troponin through a molecular-scale complex containing antibodies. The troponin-bound molecular complex is then quantified through silver enhancement of the functionalized gold. Assays in this format can be rapidly configured and implemented for a wide array of potential biomarkers. For cTnI we have demonstrated a robust and ultra-sensitive assay with an LOD of less than 500 femtograms of rat cTnI per mL serum, and an overall CV of less than 20%. The assay also shows very low background, a broad dynamic range and over 3 logs of linear dose response. As an example of the potential of high sensitivity, the nanoparticle-based rat cTnI assay could significantly increase the effectiveness of measuring drug-induced heart damage at very low drug dosages and early times. Such sensitive and early measurements can improve examination of the safety of drug candidates while correspondingly reducing drug development time and cost.

[Table: see text]
Epidermal growth factor receptor intron 1 (CA)n dinucleotide repeat polymorphism and mutations associated with the responsiveness of molecular targeted therapy in lung cancer
Authors: Wang J. , Zhang S. , Lai R.
Published: August 2020

e14595

Background: To explore EGFR gene intron 1 (CA)n repeat polymorphism and mutations associated with the responsiveness of molecular targeted therapy in lung cancer. Methods: Both observed groups consisted of 116 somatic specimens of lung cancer and controls consisted of 20 peripheral blood samples were analyzed by direct DNA sequencing of EGFR mutations at exons 18,19,21. Also (CA)n repeat polymorphisms in intron 1 of EGFR from 48 specimens were analyzed. 45 lung cancer patients were followed up. Results: EGFR mutations were found in 24 of 116 somatic specimens (20.69%). Response rate and disease control rate to EGFR TKIs was significantly higher in the patients with EGFR mutations (62.5% vs. 0)(P<0.0l),(100% vs.44.4%) (P<0.05)respectively than those without it in observed groups.In patients harboring EGFR mutations, disease control rate to patients treated with Iressa (100%) was significantly higher than those who never treated with it (40%)(P<0.05). The frequency distribution of EGFR intron 1 (CA)n repeat in 48 specimens was 23(47.9%)low (CA)n repeat(CA≤16)and 25 (52.1%) high repeat(CA>16). There was no significant difference in response rate and disease control rate of EGFR TKIs treatment between low and high (CA)n repeat numbers both in 16 patients with mutations and 18 patients without mutations in observed groups(P>0.05). Conclusions: Somatic mutations of EGFR is a major determinant of EGFR TKIs response in lung cancer. There was no significant difference in response rate and disease control rate of EGFR TKIs treatment between low (CA) n repeat patients and high repeat ones under the consideration of the mutant factor.

No significant financial relationships to disclose.
Telomerase interference in combination with docetaxel therapy for maximal prostate cancer inhibition: In vitro data for a novel therapeutic approach
Authors: Sahu D. , Xu T. , Lau R. , Xue L. , Goldkorn A.
Published: August 2020

e14596

Background: Metastatic castration-resistant prostate cancer (mCRPC) carries a median survival of 18 months with standard docetaxel based therapies. Telomerase interference (TI) is a promising novel therapeutic strategy that exploits the high telomerase activity in cancer cells by introducing a mutated telomerase RNA (MT-Ter) that encodes toxic telomeres and rapidly induces apoptosis. We investigated whether TI can be combined with docetaxel therapy to achieve greater growth inhibition in mCRPC. Methods: PC3 and DU145 mCRPC cell lines were treated with docetaxel in the presence of TI or vector control. TI was accomplished by concurrent lentiviral expression of 2 constructs: telomerase RNA with an altered template region (MT-Ter) and siRNA targeting wild-type telomerase RNA (anti-Ter siRNA). Telomere length and telomerase activity were assessed using RT-PCR and TRAP, respectively. Proliferation, apoptosis, and DNA damage were quantified using MTS, TUNEL, and 53bp1 staining, respectively. Statistical significance was calculated using a 2-sided t-test. Results: Docetaxel (10nM) induced 22% inhibition (p=0.01) of PC3 proliferation in the presence of vector control and 41% inhibition (p=0.001) in the presence of TI (results were similar in DU145 cells). This near-doubling of efficacy was attributable to an independent inhibitory effect (17% inhibition, p=0.04) from TI treatment alone, which occurred without change in bulk telomere length or telomerase activity. TI alone generated increased numbers of DNA damage foci (7/cell vs. 2/cell with vector control) while docetaxel alone did not generate significant increases in DNA damage. Both TI and docetaxel induced a marked increase in the rate of apoptosis. Conclusions: Docetaxel and TI each exerted a pro-apoptotic effect which, when combined, produced an additive inhibition of mCRPC proliferation. TI-mediated apoptosis ensued from DNA damage, consistent with its known telomeric-uncapping effect, while docetaxel-induced apoptosis was not associated with direct DNA damage, also consistent with known docetaxel mechanisms of action. These findings underscore the therapeutic promise of combining standard agents with TI to improve efficacy and reduce toxicity.

No significant financial relationships to disclose.
Pilot study of fixed-dose bevacizumab (200 mg) for solid malignancies
Authors: Reddy S. K. , Curti M. , Janis M. , Minow R.
Published: August 2020

e14600

Background: We report our initial experience with fixed dose bevacizumab at 200mg (approximately 3mg/kg). Phase I studies suggested that an optimal dose for phase II studies with bevacizumab is 3mg/kg and that circulating VEGF was undetectable at 0.3mg/kg. (Gordon et al. JCO 2001) We proposed a fixed-dose regimen of bevacizumab which we hypothesized would yield equivalent response rates with reduced toxicities and cost versus higher-dose regimens. Patients with advanced malignancies for whom bevacizumab would be indicated were analyzed. Methods: 15 patients were treated with 200mg bevacizumab in combination with antineoplastic therapy. 6 patients had NSCLCa, 8 patients had Colorectal cancer, and 1 patient had BRCA. Results: 15 patients are evaulable for response and have completed a total of 234 doses of bevacizumab (median number of doses =13) with no grade III/IV toxicity, or bevacizumab associated toxicities seen. No grade III or greater hypertension was observed. Proteinuria was not formally assessed, but no grade 3 or greater proteinuria was reported. All patients are evaluable for response with overall response rate of 33% (5/15). With a median follow-up (from the start of bevacizumab) of 452 days (222–1,699 days), median survival has not been reached with only 2 deaths. Conclusions: Fixed dose bevacizumab appears to be effective, less toxic, significantly less expensive and supported by biologic rationale and prior phase I studies and warrants further investigation. Additional patients will be accrued in a prospective phase II trial.

[Table: see text]
Activity of mTOR-Inhibitor Rad001 (everolimus) in differentiated and anaplastic thyroid cancer cell lines
Authors: Behlendorf T. , Voigt W. , Mueller T. , Jordan K. , Arnold D. , Schmoll H.
Published: August 2020

e14608

Background: Recent data suggest that aberrant activation of PIK3/AKT-pathway and mTOR are involved in the development of thyroid cancer, particularly of anaplastic (ATC) and follicular (FTC) subtype. Therefore, mTOR could be a potential treatment target in thyroid cancer. Methods: To asses the potential role of mTOR as target for the treatment of thyroid cancer, two human ATC cell lines SW1736 and 8505C, the papillary thyroid cancer (PTC) cell line BCPAP and the FTC cell line FTC133 were exposed for 96h to increasing concentrations of the mTOR inhibitor RAD001 (Everolimus, kindly provided by Novartis, Switzerland). For combination experiments 10 nM of RAD001 were combined with increasing concentrations of either doxorubicin (DOX) or cisplatin (CDDP) continuously. Cytotoxicity was measured using the sulforhodamine B assay. IC50-values were calculated with Sigma Plot (Jandel Scientific) and drug interaction was determined by the model of Drewinko. Results: The observed IC50-values of RAD001 were 1nM (FTC133), 10 nM (BCPAP), 1000 nM (SW1736) and 9400 nM (8505C). In contrast to the pronounced differences in sensitivity as assessed on the basis of IC50, a growth inhibitory effect ≥ 25 % was seen in all cell lines at a concentration of 1 nM of RAD001. IC50 for CDDP ranged from 1,3–4,8 μM and for DOX from 8–40 nM. Combination of 10 nM RAD001 with either DOX or CDDP resulted in additive drug interaction with the exception in cell line 8505C where significant synergy was found for the combination with CDDP. Conclusion: RAD001 exerted interesting preclinical activity in two differentiated thyroid cancer cell lines. Mainly additive drug interaction in thyroid cancer cell lines was observed for combinations with CDDP and DOX. Mechanistic investigations are underway and will be presented at the meeting. At least for differentiated thyroid cancer mTOR-inhibition appeared promising, further evaluation in thyroid cancer seems warranted.

No significant financial relationships to disclose.
Dual inhibition of αV integrins and Src kinase activity in colon cancer cells
Authors: Starodub A. , Jia J. , Cushman S. , Marshall D. , Hurwitz H. I. , Nixon A. B.
Published: August 2020

e14609

Background: Integrins are commonly upregulated in tumor cells and are important regulators of invasion and metastasis. Integrin signaling is initiated upon engagement of ECM and requires Src as well as various other proteins including ILK, FAK, and paxillin. Methods: Presence of αv integrins on CRC cell lines was established by flow cytometry. CNTO 95 (10μg/ml, a monoclonal anti-αv integrin antibody; Ortho Biotech), and dasatinib (<200nM; BMS, src small molecule inhibitor) were used to study the effects of combined integrin and src inhibition on proliferation and serum-induced migration of colon cancer cell lines in vitro. Downstream signaling changes were assessed by immunoblotting for phosphorylated forms of src, FAK (Y397, Y576/577 and Y925), paxillin, GSK3β and AKT (S473) in HT29, HCT116 and RKO. Results: Proliferation was inhibited by dasatinib in HT29, HCT116, DLD1 and HCT15 in a dose-dependent manner, while RKO and SW48 were resistant. Combining CNTO 95 with dasatinib further inhibited proliferation in all dasatinib-sensitive cells, yet resistant cells were unaffected. Migration was blocked by both CNTO 95 and dasatinib in all cell lines, and combining the two drugs produced augmented effect. Src activation and src- dependent FAK phosphorylation at sites 576 and 925 were blocked by dasatinib; CNTO 95 had little effect alone, but potentiated the effect of dasatinib. Paxillin phosphorylation was modestly blocked by both compounds, but the combination produced significantly augmented inhibition in the three cell lines tested. The phosphorylation status of AKT and GSK-3β, which are downstream of ILK, was inhibited by both drugs as single agents. The combination of dasatinib and CNTO 95 produced further inhibition. Conclusions: Dual inhibition of Src by dasatinib and αv integrins by CNTO 95 produced additive to synergistic inhibition of proliferation in dasatinib sensitive CRC cell lines, and inhibition of migration in all cell lines tested. Decreased phospho-paxillin levels may be responsible for the pronounced inhibition of migration observed after dual treatment with dasatinib and CNTO 95 in these CRC cell lines. These data support the rationale for combined Src/integrin inhibition in colon cancer, and further suggest approaches to patient selection strategies.

[Table: see text]
APX3330 inhibition of the redox function of ape-1/ref-1 (Ref-1) in promyelocytic leukemia cells enhances retinoic acid (ATRA) induced myeloid differentiation and limits cell proliferation as an approach to the prevention of the retinoic acid syndrome (RAS)
Authors: Robertson K. A. , Colvin E. S. , Kelley M. R. , Fishel M. L.
Published: August 2020

e14613

Background: ATRA + chemotherapy has improved the treatment of promyelocytic leukemia(APL). However, 25% of ATRA treated APL patients experience toxicities that comprise the RAS (life-threatening respiratory distress, edema, renal failure, hypotension, coagulopathy and rising blast count). One approach to prevent RAS is to limit blast proliferation and enhance myeloid differentiation. Ref-1 is a DNA repair protein that functions in redox regulation of cellular proteins, such as Fos, Jun, p53, and NFkB. HL60 myeloid leukemia cells are promyeloblasts that respond to ATRA with granulocytic differentiation/growth arrest. Prior studies suggest Ref-1 redox control is integral to ATRA-induced differentiation. To define the role of the redox function of Ref-1, we used the Ref-1 specific drug, APX3330, to block Ref-1 redox function and examined the response of HL60 cells to ATRA. Methods: Cell growth assessed using trypan blue. Differentiation was evaluated by morphology and expression of CD11b by flow cytometry. Apoptosis was assayed by annexin-PI staining on flow cytometry and cell cycle analysis assayed with propidium iodide flow cytometry. To assess activation of the MAPK pathway, BLR-1 expression was determined by real time PCR. Results: 1) APX3330 blockade of Ref-1 redox function resulted in limited cell growth yet a profound increase in differentiation and a moderate increase in apoptosis. 2) dose dependent studies with ATRA showed a similar degree of differentiation in cells treated with 10 μM ATRA to cells treated with APX3330 + 0.01 μM ATRA; allowing HL60 cells + APX3330 to give a similar response to a 1000 fold lower dose of ATRA. APX3330 alone did not induce differentiation and induced only minimal apoptosis but in combination with ATRA, increased the number of cells in G1/G0 phase significantly. 3) APX3330 + ATRA increased BLR-1 expression significantly by real time PCR suggesting enhanced activation of the MAPK pathway. Conclusions: APX3330 + ATRA limits HL60 growth and dramatically enhances terminal granulocytic differentiation. These finding may provide a therapeutic approach for prevention of the RAS.

No significant financial relationships to disclose.
Preclinical development of orally available sphingosine kinase inhibitors
Authors: Smith C. D. , Maines L. W. , Zhuang Y. , Green C. L. , Keller S. N. , Beljanski V. , Knaak C. , Wang W.
Published: August 2020

e14615

Background: Sphingolipid-metabolizing enzymes control the dynamic balance of important bioactive lipids, including apoptotic ceramide and proliferative sphingosine 1-phosphate (S1P). Several growth factors and inflammatory cytokines promote the cleavage of sphingomyelin and ceramide leading to rapid elevation of S1P levels through the action of sphingosine kinases (SKs). SK1 is oncogenic and is markedly overexpressed in a variety of human cancers, making this enzyme a potential molecular target for cancer therapy. Methods: SK inhibitors were synthesized and evaluated in a variety of cellular and in vivo models. Antitumor activity was assessed in an allogeneic model utilizing murine JC mammary adenocarcinoma cells growing in Balb/c mice, and a xenograft model of human Bxpc pancreatic adenocarcinoma cells growing in scid-mice. Results: The lead SK inhibitors, called ABC294640 and ABC294735, inhibit SK1 and SK2 at low micromolar concentrations, and are nontoxic to rodents at acute doses up to at least 1000 mg/kg (po). ABC294640 is orally-available, and has excellent pharmacokinetics, with serum levels exceeding the effective SK inhibitory concentration for at least 8 hours. Acute- and chronic- toxicology studies indicate that ABC294640 induces a transient minor decrease in the hemotocrit of rats and mice receiving 100 and 250 mg/kg/day; however, this normalizes by 28 days of treatment. No other changes in hematology parameters, or gross or microscopic tissue pathology result from treatment with ABC294640. Oral administration of ABC294640 to mice bearing JC adenocarcinomas results in dose-dependent antitumor activity associated with depletion of S1P levels in the tumors and progressive tumor cell apoptosis. ABC294735 is also orally-active in both JC and Bxpc tumor models, and demonstrates synergistic antitumor activity when combined with cisplatin or gemcitabine. Conclusions: These newly developed SK inhibitors provide orally-available drug candidates for the treatment of pancreatic cancer and other diseases. IND-enabling CMC and toxicology work is currently underway, and an SK inhibitor is expected to enter clinical trials in early 2010.

[Table: see text]
Evaluation of anticancer drugs in NSCLC
Authors: Guirgis H. M.
Published: August 2020

e14616

Background: Methodology to evaluate anti-cancer drugs in GI malgnancies was previoulsy reported. It has been estimated that the society would be willing to pay $50,000-$100,000 per life-year S gain (S Negrier et, 2007). Objectives: Design scoring model methodology to evaluate and grade anti-cancer drugs in NSCLC with emphasis on the association between between S, AEs, A and C. Methodology: 0S and AEs data were abstracted from J Douillard, R Herbert, Le Chevalier, C Mangeold, A Sandler, F Shepard, R Rossell and C Thienelt (2005–2008). A was graded in points (P) from 3 oral to zero daily injections. AEs: 4 (placebo) to 0 (fatalities) using CTCAE v 3.0. S gain (days,d) was calculated in a corrected ratio of S/360 (SR); Cost R: as C/d/s/$1500, divided by (A+ AEs), corrected and expressed as C scores. C in US $ was based on treating one patient for entire course,70 kg or 1.7/ m2. Using a grading scale from A to D, Survival > 360d, SR>10; C/d/s up to $63 and CR up to 4.2 were rated as (A+) while S< 15d, SR <0.42, C/d/s> $1500 and CR>100 as (D). Results: Examples shown in Table . Adj Cis + Vin after resection in stage II and III scored the highest SR and lowest CR with A+ rating. However, there was a lesser SR using the same combination in mNSCLC. OS markedly improved with Er and BV in 2nd-line. Addition of Cetuximab (Cet) to Cis and Vin demonstrated modest S gain at a much higher CR. Bevacizumab (BV) combined with Pac + Car improved OS over Pac + Car in 1st and 2nd lines at higher CR. Combination of BV, Cis and Gemcitabine demonstrated the lowest S, highest CR and D rating. Discussion: S and C were calculated as Ratios. C scores were based on the association of S with arbitrary but relative weights assigned to AEs and A. BV and Er improved OS in 2nd line, in contrast to phase III Beta study. Adjuvant Cis+Vin seems to be cost-effective. Increased CR was not necessarily associated with improved S. Grading of drugs varied depending on S or C. Higher C/d/s, increased AEs and cumbersome A resulted in higher C scores. Conclusions: SR, CR and possibly C scores might be advantageous in evaluation, grading and comparison of anti-cancer drugs. [Table: see text]

No significant financial relationships to disclose.
MET in small cell lung carcinoma (SCLC): Effects of a MET inhibitor in SCLC cell lines and prognostic role of MET status in patients
Authors: Cañadas I. , Arumi M. , Lema L. , Martinez A. , Grande E. , Bellosillo B. , Rojo F. , Rovira A. , Albanell J. , Arriola E.
Published: August 2020

e14617

Purpose: HGF/MET pathway is aberrantly activated by receptor overexpression and mutations in SCLC preclinical models, enhancing their oncogenicity. The significance of MET expression in SCLC remains unclear. Our aim was to analyze the effects of MET inhibition in chemosensitive/refractory SCLC models and to study the expression pattern and prognostic impact of total and phosphorylated (p) MET in SCLC patients. Methods: Total and p-MET expression (Western Blot), gene copy number (FISH), and exon 14 activating mutations (sequencing) were evaluated in H69 and H69AR SCLC cell lines. PHA-665752 (PHA), alone or combined with doxorubicin, was used to study the effects of pathway inhibition on viability, colony formation and invasion assays in basal/stimulated conditions (HGF). Fifty-eight SCLC cases were evaluated for MET and p-MET expression by immunohistochemistry. Survival analyses were performed. Results: H69 and H69AR (both R988C mutated) expressed MET at basal conditions, but not p-MET. HGF induced MET phosphorylation, increased proliferation (20%) and protected cells from doxorubicin cytotoxicity. PHA 0.5μM blocked MET phosphorylation, decreased colony formation by 50% in H69, counteracted the cytoprotective effect of HGF and inhibited invasion in H69AR. MET expression was found in 98% normal bronchial epithelia, and 78% tumor samples (overexpression 38%). Activated MET was focally detected in normal and metaplastic mucosa and expressed in 22% tumors. MET expression was associated with improved overall and disease free survival (p: 0.06 and 0.051, respectively). All p-MET positive cases within MET expressing tumors, showed relapsed disease (83% in negative p-MET samples, p=0.065), suggesting MET activation may revert the good prognosis linked to total MET expression. Conclusions: MET activation, results in a more aggressive phenotype in SCLC cells. PHA at MET inhibiting concentrations reverses this phenotype. In SCLC specimens, MET expression was more prevalent than p-MET and associated with raised prognosis. All these data suggest that studies with MET inhibitors should focus on p-MET positive SCLC.

[Table: see text]