Artificial intelligence-assisted digital pathology for non-alcoholic steatohepatitis: current status and future directions

The worldwide prevalence of non-alcoholic steatohepatitis (NASH) is increasing, causing a significant medical burden, but no approved therapeutics are currently available. NASH drug development requires histological analysis of liver biopsies by expert pathologists for trial enrolment and efficacy assessment, which can be hindered by multiple issues including sample heterogeneity, inter-reader and intra-reader variability, and ordinal scoring systems. Consequently, there is a high unmet need for accurate, reproducible, quantitative, and automated methods to assist pathologists with histological analysis to improve the precision around treatment and efficacy assessment. Digital pathology (DP) workflows in combination with artificial intelligence (AI) have been established in other areas of medicine and are being actively investigated in NASH to assist pathologists in the evaluation and scoring of NASH histology. DP/AI models can be used to automatically detect, localise, quantify, and score histological parameters and have the potential to reduce the impact of scoring variability in NASH clinical trials. This narrative review provides an overview of DP/AI tools in development for NASH, highlights key regulatory considerations, and discusses how these advances may impact the future of NASH clinical management and drug development. This should be a high priority in the NASH field, particularly to improve the development of safe and effective therapeutics.

Selectivity matters: selective ROCK2 inhibitor ameliorates established liver fibrosis via targeting inflammation, fibrosis, and metabolism

The pathogenesis of hepatic fibrosis is driven by dysregulated metabolism precipitated by chronic inflammation. Rho-associated coiled-coil-containing protein kinases (ROCKs) have been implicated in these processes, however the ability of selective ROCK2 inhibition to target simultaneously profibrotic, pro-inflammatory and metabolic pathways remains undocumented. Here we show that therapeutic administration of GV101, a selective ROCK2 inhibitor with more than 1000-fold selectivity over ROCK1, attenuates established liver fibrosis induced by thioacetamide (TAA) in combination with high-fat diet in mice. GV101 treatment significantly reduces collagen levels in liver, associated with downregulation of pCofilin, pSTAT3, pAkt, while pSTAT5 and pAMPK levels are increased in tissues of treated mice. In vitro, GV101 inhibits profibrogenic markers expression in fibroblasts, adipogenesis in primary adipocytes and TLR-induced cytokine secretion in innate immune cells via targeting of Akt-mTOR-S6K signaling axis, further uncovering the ROCK2-specific complex mechanism of action and therapeutic potential of highly selective ROCK2 inhibitors in liver fibrosis.

Nuclear envelope disruption triggers hallmarks of aging in lung alveolar macrophages

Aging is characterized by gradual immune dysfunction and increased disease risk. Genomic instability is considered central to the aging process, but the underlying mechanisms of DNA damage are insufficiently defined. Cells in confined environments experience forces applied to their nucleus, leading to transient nuclear envelope rupture (NER) and DNA damage. Here, we show that Lamin A/C protects lung alveolar macrophages (AMs) from NER and hallmarks of aging. AMs move within constricted spaces in the lung. Immune-specific ablation of lamin A/C results in selective depletion of AMs and heightened susceptibility to influenza virus-induced pathogenesis and lung cancer growth. Lamin A/C-deficient AMs that persist display constitutive NER marks, DNA damage and p53-dependent senescence. AMs from aged wild-type and from lamin A/C-deficient mice share a lysosomal signature comprising CD63. CD63 is required to limit damaged DNA in macrophages. We propose that NER-induced genomic instability represents a mechanism of aging in AMs.

Molecular imaging of liver inflammation using an anti-VCAM-1 nanobody

To date, a biopsy is mandatory to evaluate parenchymal inflammation in the liver. Here, we evaluated whether molecular imaging of vascular cell adhesion molecule-1 (VCAM-1) could be used as an alternative non-invasive tool to detect liver inflammation in the setting of chronic liver disease. To do so, we radiolabeled anti-VCAM-1 nanobody (99mTc-cAbVCAM1-5) and used single-photon emission computed tomography (SPECT) to quantify liver uptake in preclinical models of non-alcoholic fatty liver disease (NAFLD) with various degree of liver inflammation: wild-type mice fed a normal or high-fat diet (HFD), FOZ fed a HFD and C57BL6/J fed a choline-deficient or -supplemented HFD. 99mTc-cAbVCAM1-5 uptake strongly correlates with liver histological inflammatory score and with molecular inflammatory markers. The diagnostic power to detect any degree of liver inflammation is excellent (AUROC 0.85-0.99). These data build the rationale to investigate 99mTc-cAbVCAM1-5 imaging to detect liver inflammation in patients with NAFLD, a largely unmet medical need.

Selective adipocyte loss of Angiopoietin-2 prompts female-specific obesity and metabolic syndrome

Thermogenic fat differentiation and function can be promoted through multiple pathways, resulting in a common cell phenotype characterized by the expression of Uncoupling Protein-1 and the ability to dissipate energy, but local and systemic stimuli are necessary to promote adequate thermogenic fat vascularization, which is a precondition for the transport of substrate and the dissipation of heat. Angiopoietin-2 is an important driver of vascularization, and its transcription is in part promoted by estrogen signaling. In this study we demonstrate that adipose tissue-specific knock out of Angiopoietin-2 causes a female-specific reduced thermogenic fat differentiation and function, resulting in obesity and impaired glucose tolerance with end-organ features consistent with metabolic syndrome. In humans, angiopoietin-2 levels are higher in females than in males, and are inversely correlated with adiposity and age more strongly in pre-menopause when compared to post-menopause. Collectively, these data indicate a novel and important role for estrogen-mediated Angiopoietin-2 adipose tissue production in the protection against calorie overload in females, and potentially in the development of postmenopausal weight gain.

Cigarette smoke-induced gasdermin D activation in bronchoalveolar macrophages and bronchial epithelial cells dependently on NLRP3

Chronic pulmonary inflammation and chronic obstructive pulmonary disease (COPD) are major health issues largely due to air pollution and cigarette smoke (CS) exposure. The role of the innate receptor NLRP3 (nucleotide-binding domain and leucine-rich repeat containing protein 3) orchestrating inflammation through formation of an inflammasome complex in CS-induced inflammation or COPD remains controversial. Using acute and subchronic CS exposure models, we found that Nlrp3-deficient mice or wild-type mice treated with the NLRP3 inhibitor MCC950 presented an important reduction of inflammatory cells recruited into the bronchoalveolar space and of pulmonary inflammation with decreased chemokines and cytokines production, in particular IL-1β demonstrating the key role of NLRP3. Furthermore, mice deficient for Caspase-1/Caspase-11 presented also decreased inflammation parameters, suggesting a role for the NLRP3 inflammasome. Importantly we showed that acute CS-exposure promotes NLRP3-dependent cleavage of gasdermin D in macrophages present in the bronchoalveolar space and in bronchial airway epithelial cells. Finally, Gsdmd-deficiency reduced acute CS-induced lung and bronchoalveolar space inflammation and IL-1β secretion. Thus, we demonstrated in our model that NLRP3 and gasdermin D are key players in CS-induced pulmonary inflammation and IL-1β release potentially through gasdermin D forming-pore and/or pyroptoctic cell death.

GNS561, a clinical-stage PPT1 inhibitor, is efficient against hepatocellular carcinoma via modulation of lysosomal functions

Hepatocellular carcinoma is the most frequent primary liver cancer. Macroautophagy/autophagy inhibitors have been extensively studied in cancer but, to date, none has reached efficacy in clinical trials. In this study, we demonstrated that GNS561, a new autophagy inhibitor, whose anticancer activity was previously linked to lysosomal cell death, displayed high liver tropism and potent antitumor activity against a panel of human cancer cell lines and in two hepatocellular carcinoma in vivo models. We showed that due to its lysosomotropic properties, GNS561 could reach and specifically inhibited its enzyme target, PPT1 (palmitoyl-protein thioesterase 1), resulting in lysosomal unbound Zn²⁺ accumulation, impairment of cathepsin activity, blockage of autophagic flux, altered location of MTOR (mechanistic target of rapamycin kinase), lysosomal membrane permeabilization, caspase activation and cell death. Accordingly, GNS561, for which a global phase 1b clinical trial in liver cancers was just successfully achieved, represents a promising new drug candidate and a hopeful therapeutic strategy in cancer treatment.

Abbreviations: ANXA5:annexin A5; ATCC: American type culture collection; BafA1: bafilomycin A₁; BSA: bovine serum albumin; CASP3: caspase 3; CASP7: caspase 7; CASP8: caspase 8; CCND1: cyclin D1; CTSB: cathepsin B; CTSD: cathepsin D; CTSL: cathepsin L; CQ: chloroquine; iCCA: intrahepatic cholangiocarcinoma; DEN: diethylnitrosamine; DMEM: Dulbelcco’s modified Eagle medium; FBS: fetal bovine serum; FITC: fluorescein isothiocyanate; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; HCC: hepatocellular carcinoma; HCQ: hydroxychloroquine; HDSF: hexadecylsulfonylfluoride; IC₅₀: mean half-maximal inhibitory concentration; LAMP: lysosomal associated membrane protein; LC3-II: phosphatidylethanolamine-conjugated form of MAP1LC3; LMP: lysosomal membrane permeabilization; MALDI: matrix assisted laser desorption ionization; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MKI67: marker of proliferation Ki-67; MTOR: mechanistic target of rapamycin kinase; MRI: magnetic resonance imaging; NH₄Cl: ammonium chloride; NtBuHA: N-tert-butylhydroxylamine; PARP: poly(ADP-ribose) polymerase; PBS: phosphate-buffered saline; PPT1: palmitoyl-protein thioesterase 1; SD: standard deviation; SEM: standard error mean; vs, versus; Zn²⁺: zinc ion; Z-Phe: Z-Phe-Tyt(tBu)-diazomethylketone; Z-VAD-FMK: carbobenzoxy-valyl-alanyl-aspartyl-[O-methyl]- fluoromethylketone.

Abstract 899: Remarkable anti-tumor response in a HCC transgenic mouse model treated with GNS561 in combination with anti-PD1

Introduction:Hepatocellular carcinoma (HCC) is the most frequent primary liver cancer, leading to 75,000 deaths annually. Immunotherapeutic intervention has emerged as a novel effective treatment to delay the progression of aggressive tumors and suppress tumor recurrence and metastasis. However, few clinical immunotherapy trials have been conducted in HCC patients and there is an unmet need for novel therapeutic strategies. Combinations of conventional and novel treatments with immune-oncologic agents are now regarded as a therapy that can dramatically improve the outcome of patients with HCC.GNS561 is a lysosomotropic small molecule that was investigated in the context of antitumor activity alone or in combination with a PD-1 inhibitor using a transgenic immunocompetent mouse model (ASV-B).

Materials and Methods: 40 ASV-B mice were treated with either the vehicle (p.o. water pH= 4, 5 days per week), GNS561 (p.o. 50 mg/kg/5 days per week), mouse anti-PD1 antibody (i.p. 10 mg/kg/twice a week [BIW]) or a combination of GNS561 and mouse anti-PD1 (p.o. 50 mg/kg/5 days per week and i.p. 10 mg/kg/BIW respectively) for 8 weeks. Tumor burden was evaluated by measuring the liver volume and blood flow velocity in the coeliac trunk by US/doppler 4 and 8 weeks (W8) after treatment start, the macronodules count and liver weight at sacrifice (W8). Intra and peritumoral CD8+ cells were counted.

Results: All treatments were well tolerated. No significant response was observed with the anti-PD1 monotherapy compared with the vehicle. At W8, GNS561 alone or in combination with an anti-PD-1 showed a significant rapid and durable tumor response based on the macronodule count, decreased liver blood flow in the coeliac trunk, liver volume and weight (-59% and -77%; -18% and -31%; -36% and -37%; -37% and -52%, respectively). Based on preliminary mechanistic data, GNS561 alone or in combination showed an increase in the count of CD8+ cells penetrating the tumor site compared to the vehicle and the anti-PD1 alone, suggesting GNS561 may reinstore the anti-PD1 activity by facilitating CD8+ cells to reach the tumor site to exert their antitumoral activity.

Conclusion: GNS561 alone or in combination with an anti-PD1 showed a significant antitumoral response. A combination of GNS561 with an anti-PD1 could then be of clinical interest in the treatment of hepatocelullar carcinoma.

Citation Format: Madani Rachid, Annemilaï Tijeras-Raballand, Cindy Serdjebi, Sonia Brun, Christelle Ansaldi, Eric Raymond, Philippe Halfon. Remarkable anti-tumor response in a HCC transgenic mouse model treated with GNS561 in combination with anti-PD1 [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 899.

GNS561 acts as a potent anti-fibrotic and pro-fibrolytic agent in liver fibrosis through TGF-β1 inhibition

Background:

Hepatic fibrosis is the result of chronic liver injury that can progress to cirrhosis and lead to liver failure. Nevertheless, there are no anti-fibrotic drugs licensed for human use. Here, we investigated the anti-fibrotic activity of GNS561, a new lysosomotropic molecule with high liver tropism.

Methods:

The anti-fibrotic effect of GNS561 was determined in vitro using LX-2 hepatic stellate cells (HSCs) and primary human HSCs by studying cell viability, activity of caspases 3/7, autophagic flux, cathepsin maturation and activity, HSC activation and transforming growth factor-β1 (TGF-β1) maturation and signaling. The contribution of GNS561 lysosomotropism to its anti-fibrotic activity was assessed by increasing lysosomal pH. The potency of GNS561 on fibrosis was evaluated in vivo in a rat model of diethylnitrosamine-induced liver fibrosis.

Results:

GNS561 significantly decreased cell viability and promoted apoptosis. Disrupting the lysosomal pH gradient impaired its pharmacological effects, suggesting that GNS561 lysosomotropism mediated cell death. GNS561 impaired cathepsin activity, leading to defective TGF-β1 maturation and autophagic processes. Moreover, GNS561 decreased HSC activation and extracellular matrix deposition by downregulating TGF-β1/Smad and mitogen-activated proteine kinase signaling and inducing fibrolysis. Finally, oral administration of GNS561 (15 mg/kg per day) was well tolerated and attenuated diethylnitrosamine-induced liver fibrosis in this rat model (decrease of collagen deposition and of pro-fibrotic markers and increase of fibrolysis).

Conclusion:

GNS561 is a new potent lysosomotropic compound that could represent a valid medicinal option for hepatic fibrosis treatment through both its anti-fibrotic and its pro-fibrolytic effects. In addition, this study provides a rationale for targeting lysosomes as a promising therapeutic strategy in liver fibrosis.

Quantitative mathematical modeling of clinical brain metastasis dynamics in non-small cell lung cancer

Brain metastases (BMs) are associated with poor prognosis in non-small cell lung cancer (NSCLC), but are only visible when large enough. Therapeutic decisions such as whole brain radiation therapy would benefit from patient-specific predictions of radiologically undetectable BMs. Here, we propose a mathematical modeling approach and use it to analyze clinical data of BM from NSCLC. Primary tumor growth was best described by a gompertzian model for the pre-diagnosis history, followed by a tumor growth inhibition model during treatment. Growth parameters were estimated only from the size at diagnosis and histology, but predicted plausible individual estimates of the tumor age (2.1–5.3 years). Multiple metastatic models were further assessed from fitting either literature data of BM probability (n = 183 patients) or longitudinal measurements of visible BMs in two patients. Among the tested models, the one featuring dormancy was best able to describe the data. It predicted latency phases of 4.4–5.7 months and onset of BMs 14–19 months before diagnosis. This quantitative model paves the way for a computational tool of potential help during therapeutic management.

EGFR and KRAS Mutations Predict the Incidence and Outcome of Brain Metastases in Non-Small Cell Lung Cancer

Background: Lung cancer is the leading cause of brain metastases (BM). The identification of driver oncogenes and matched targeted therapies has improved outcome in non-small cell lung cancer (NSCLC) patients; however, a better understanding of BM molecular biology is needed to further drive the process in this field. Methods: In this observational study, stage IV NSCLC patients tested for EGFR and KRAS mutations were selected, and BM incidence, recurrence and patients’ outcome were assessed. Results: A total of 144 patients (142 Caucasian and two Asian) were selected, including 11.27% with EGFR-mutant and 33.10% with KRAS-mutant tumors, and 57.04% patients had developed BM. BM incidence was more frequent in patients with EGFR mutation according to multivariate analyses (MVA) (Odds ratio OR = 8.745 [1.743–43.881], p = 0.008). Among patients with treated BM, recurrence after local treatment was less frequent in patients with KRAS mutation (OR = 0.234 [0.078–0.699], p = 0.009). Among patients with untreated BM, overall survival (OS) was shorter for patients with KRAS mutation according to univariate analysis (OR = 7.130 [1.240–41.012], p = 0.028), but not MVA. Conclusions: EGFR and KRAS mutations have a predictive role on BM incidence, recurrence and outcome in Caucasian NSCLC patients. These results may impact the routine management of disease in these patients. Further studies are required to assess the influence of other biomarkers on NSCLC BM.

In Vivo Bioluminescence Tomography for Monitoring Breast Tumor Growth and Metastatic Spreading: Comparative Study and Mathematical Modeling

This study aimed at evaluating the reliability and precision of Diffuse Luminescent Imaging Tomography (DLIT) for monitoring primary tumor and metastatic spreading in breast cancer mice, and to develop a biomathematical model to describe the collected data. Using orthotopic mammary fat pad model of breast cancer (MDAMB231-Luc) in mice, we monitored tumor and metastatic spreading by three-dimensional (3D) bioluminescence and cross-validated it with standard bioluminescence imaging, caliper measurement and necropsy examination. DLIT imaging proved to be reproducible and reliable throughout time. It was possible to discriminate secondary lesions from the main breast cancer, without removing the primary tumor. Preferential metastatic sites were lungs, peritoneum and lymph nodes. Necropsy examinations confirmed DLIT measurements. Marked differences in growth profiles were observed, with an overestimation of the exponential phase when using a caliper as compared with bioluminescence. Our mathematical model taking into account the balance between living and necrotic cells proved to be able to reproduce the experimental data obtained with a caliper or DLIT imaging, because it could discriminate proliferative living cells from a more composite mass consisting of tumor cells, necrotic cell, or inflammatory tissues. DLIT imaging combined with mathematical modeling could be a powerful and informative tool in experimental oncology.

Pharmacokinetics and pharmacogenetics of Gemcitabine as a mainstay in adult and pediatric oncology: an EORTC-PAMM perspective

Gemcitabine is an antimetabolite ranking among the most prescribed anticancer drugs worldwide. This nucleoside analog exerts its antiproliferative action after tumoral conversion into active triphosphorylated nucleotides interfering with DNA synthesis and targeting ribonucleotide reductase. Gemcitabine is a mainstay for treating pancreatic and lung cancers, alone or in combination with several cytotoxic drugs (nab-paclitaxel, cisplatin and oxaliplatin), and is an option in a variety of other solid or hematological cancers. Several determinants of response have been identified with gemcitabine, i.e., membrane transporters, activating and inactivating enzymes at the tumor level, or Hedgehog signaling pathway. More recent studies have investigated how germinal genetic polymorphisms affecting cytidine deaminase, the enzyme responsible for the liver disposition of gemcitabine, could act as well as a marker for clinical outcome (i.e., toxicity, efficacy) at the bedside. Besides, constant efforts have been made to develop alternative chemical derivatives or encapsulated forms of gemcitabine, as an attempt to improve its metabolism and pharmacokinetics profile. Overall, gemcitabine is a drug paradigmatic for constant searches of the scientific community to improve its administration through the development of personalized medicine in oncology.

Yin and yang of cytidine deaminase roles in clinical response to azacitidine in the elderly: a pharmacogenetics tale

Azacitidine is a mainstay for treating hematological disorders. Azacitidine is metabolized by cytidine deaminase, coded by a highly polymorphic gene. Here, we present two elderly patients with opposite clinical outcomes after azacitidine treatment. First, an acute myeloid leukemia patient showed life-threatening toxicities, but outstanding complete remission, after a single round of azacitidine. Further investigations showed that this patient was cytidine deaminase 79A>C (rs2072671) homozygous with a marked deficient phenotype. Next, a chronic myelomonocytic leukemia patient displayed complete lack of response despite several cycles of azacitidine. This patient had a rapid-deaminator phenotype linked to the -31delC deletion (rs3215400). These polymorphisms lead to opposite clinical outcomes in patients with myelodysplastic syndromes treated with azacitidine, thus suggesting that determining cytidine deaminase status could help to forecast clinical outcome.

FFCD-1004 Clinical Trial: Impact of Cytidine Deaminase Activity on Clinical Outcome in Gemcitabine-Monotherapy Treated Patients

PURPOSE

Because cytidine deaminase (CDA) is the key enzyme in gemcitabine metabolism, numerous studies have attempted to investigate impact of CDA status (i.e. genotype or phenotype) on clinical outcome. To date, data are still controversial because none of these studies has fully investigated genotype-phenotype CDA status, pharmacokinetics and clinical outcome relationships in gemcitabine-treated patients. Besides, most patients were treated with gemcitabine associated with other drugs, thus adding a confounding factor. We performed a multicenter prospective clinical trial in gemcitabine-treated patients which aimed at investigating the link between CDA deficiency on the occurrence of severe toxicities and on pharmacokinetics, and studying CDA genotype-phenotype relationships.

EXPERIMENTAL DESIGN

One hundred twenty patients with resected pancreatic adenocarcinoma eligible for adjuvant gemcitabine monotherapy were enrolled in this study promoted and managed by the Fédération Francophone de Cancérologie Digestive. Toxicities were graded according to National Cancer Institute's Common Terminology Criteria for Adverse Events Version 4. They were considered severe for grade ≥ 3, and early when occurring during the first eight weeks of treatment. CDA status was evaluated using a double approach: genotyping for 79A>C and functional testing. Therapeutic drug monitoring of gemcitabine and its metabolite were performed on the first course of gemcitabine.

RESULTS

Five patients out of 120 (i.e., 4.6%) were found to be CDA deficient (i.e., CDA activity <1.3 U/mg), and only one among them experienced early severe hematological toxicity. There was no statistically significant difference in CDA activity between patients experiencing hematological severe toxicities (28.44%) and patients who tolerated the treatment (71.56%). CDA genetic analysis failed in evidencing an impact in terms of toxicities or in CDA activity. Regarding pharmacokinetics, a wide inter-individual variability has been observed in patients.

CONCLUSION

This study, which included only 4.6% of CDA-deficient patients, failed in identifying CDA status as a predictive marker of toxicities with gemcitabine. A lack of statistical power because of smoothing effect of CDA variability as compared with real life conditions could explain this absence of impact.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01416662.

Abstract 4506: Computational-driven metronomics: application to gemcitabine in neuroblastoma-bearing mice

Metronomics (i.e., repeated administration of small doses of drugs over a long period of time) is an attractive strategy to reduce treatment-related toxicities while possibly offering unexpected novel mechanisms of action such as anti-angiogenesis or immuno-stimulatory properties. Defining an optimal metronomic schedule remains uneasy because of the variety of possible combinations between dosing, frequency and duration. Our group has developed innovative modeling tools to optimize metronomic schedules. Here, we have used this computational approach to test whether metronomics gemcitabine would make better than standard gemcitabine in mice bearing human neuroblastoma. In silico simulation suggested that shifting from standard 100 mg/kg/w over 4 consecutive weeks to the metronomic 1 mg/kg/d schedule for 28 consecutive days would achieve higher antitumoral efficacy while being well tolerated. To test this hypothesis, 100 000 human GI-ME-N neuroblastoma cells stably transfected with luciferase were subcutaneously grafted in 40 nude mice. Mice were next split in 3 groups: control, 100 mg/kg/w gemcitabine (STD-GEM) and 1 mg/kg/d gemcitabine (MetroGem-1). An additional satellite group was treated with 0.5 mg/kg/d (MetroGem-0.5). Metro-Gem was administrated using an osmotic pump implanted subcutaneously. Efficacy (i.e., comparison in tumor growth) was the main endpoint. Pharmacokinetics, tumor inflammation, and vascular density were the secondary endpoints. Gemcitabine assay showed that whereas Cmax up to 80 μg/ml were reached in mice treated with STD-GEM, steady-state concentrations of 0.1 μg/ml only were observed in animals undergoing MetroGem-1. Measuring cathepsin expression by fluorescence imaging suggested reduced inflammation in mice treated with the metronomic schedule. Similarly, fluorescence imaging showed smaller vascular density in mice treated with MetroGem-1 or -0.5 as compared with control or STD-GEM animals. To further check a possible anti-angiogenic effect, tumor perfusion rate was measuring next using luciferine, and fully confirmed that mice treated with Metro-Gem exhibited reduced blood flow as compared with other groups. Finally, bioluminescence monitoring of tumor growth showed that whereas STD-GEM was totally ineffective, both MetroGem-1 and MetroGem-0.5 achieved 60% reduction in tumor mass at the end of the treatment (p&lt;0.05, Anova). Much interestingly, tumor growth with metronomics was kept under control for up to 40 days after stopping treatment. Overall, this study shows how computational approaches can help to refine and to rationalize metronomic dosing. Here, higher efficacy and long-lasting stabilization was achieved with metronomics. Impact on tumor angiogenesis could explain, at least partly, this increase in efficacy in a chemo-resistant model.

Citation Format: Joseph Ciccolini, Eddy Pasquier, Aurelie Lombard, Sarah Giacometti, Christian Faivre, Raphaelle Fanciullino, Cindy Serdjebi, Dominique Barbolosi, Nicolas Andre. Computational-driven metronomics: application to gemcitabine in neuroblastoma-bearing mice. [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 4506. doi:10.1158/1538-7445.AM2015-4506

Selection of the best blood compartment to measure cytidine deaminase activity to stratify for optimal gemcitabine or cytarabine treatment

Cytidine deaminase (CDA) plays a crucial role in the degradation of cytidine analogs, such as gemcitabine and cytarabine. Several studies showed that a low CDA activity is associated with more toxicity but a higher efficacy, while a high activity will lead to a lower efficacy but less toxicity. A stratified dosing strategy based on the relative CDA activity would increase efficiency. In order to predict these events, a reliable measurement of CDA with a validated method is crucial. We aimed to determine which phenotype assay would be most suitable; a spectrophotometric assay using cytidine as a substrate, or an HPLC assay using gemcitabine as a substrate. In serum and whole blood of 26 volunteers, both assays showed an excellent correlation (R>0.999), but not in plasma nor in red blood cells. Moreover, there was no difference between males and females. In conclusion, the spectrophotometric assay seems the most simple and cost-effective test. It should be performed in serum, while it should be normalized on protein content as measured by the Bicinchoninic Acid.

Pharmacogenetics and breast cancer management: current status and perspectives

INTRODUCTION

Breast cancer has benefited from a number of innovative therapeutics over the last decade. Cytotoxics, hormone therapy, targeted therapies and biologics can now be given to ensure optimal management of patients. As life expectancy of breast cancer patients has been significantly stretched and that several lines of treatment are now made available, determining the best drug or drug combinations to be primarily given and the best dosing and scheduling for each patient is critical for ensuring an optimal toxicity/efficacy balance.

AREAS COVERED

Defining patient's characteristics at the tumor level (pharmacogenomics) and the constitutional level (pharmacogenetics) is a rising trend in oncology. This review covers the latest strategies based upon the search of relevant biomarkers for efficacy, resistance and toxicity to be undertaken at the bedside to shift towards precision medicine in breast cancer patients.

EXPERT OPINION

In the expanding era of bioguided medicine, identifying relevant and clinically validated biomarkers from the plethora of published material remains an uneasy task. Sorting the variety of genetic and molecular markers that have been investigated over the last decade on their level of evidence and addressing the issue of drug exposure should help to improve the management of breast cancer therapy.

Role of cytidine deaminase in toxicity and efficacy of nucleosidic analogs

INTRODUCTION

Nucleosidic analogs such as pyrimidine and purine derivatives are mainstay in the field of treating cancers, both in adults and in children. All these drugs act as antimetabolite compounds, that is, they interfere with the ability of cancer cells to synthesize the nucleosides or the nucleotides necessary for proliferation and progression. As with most cytotoxics, maintaining patients in their therapeutic window is challenging, and predicting changes in drug exposure is critical to ensure an optimal efficacy/toxicity balance.

AREAS COVERED

Among the antimetabolites, a small but widely prescribed number of drugs (i.e., gemcitabine, capecitabine, cytarabine, azacytidine) share a same metabolic pattern driven by a liver enzyme, cytidine deaminase (CDA), coded by a gene displaying several genetic and epigenetic polymorphisms. Consequently, CDA activity is erratic, ranging from deficient to ultra-rapid deaminator patients, with subsequent impact on drug pharmacokinetics and pharmacodynamics eventually. This review provides an update on the variety of clinical studies and case-reports investigating on CDA status as a marker for clinical outcome in cancer patients treated with nucleosidic analogs.

EXPERT OPINION

Whereas sorting patients on the basis of their CDA genotype remains tricky because of unclear genotype-to-phenotype relationships, developing functional strategies (i.e., phenotype-based status determination) could help to use CDA status as a biomarker for developing adaptive dosing strategies with nucleosidic analogs.

Abstract 5549: Recipient-donor contradictory genotype with impact on anticancer drug pharmacogenetics after liver transplant: A deadly gift

A 5-year old girl with liver transplant was scheduled for a therapy including high-dose cytarabine for her Burkitt lymphoma. Cytarabine pharmacogenetics focus on cytidine deaminase (CDA) , the polymorphic liver enzyme responsible for its detoxification. Preliminary double testing for her CDA status on DNA lymphocytes showed none of the germline polymorphisms usually associated with CDA deficiency (ie, 79A&gt;C (K27Q), 208G&gt;A), but surprisingly with a functional mild deficiency syndrom. Despite 30% reduction in cytarabine dosing, life-threatening toxicities showed quickly and treatment was discontinued. Genetic HRM-based investigations performed in the patient on liver biopsy failed in generating a clear genotype. Further HRM+sequencing retrospective investigations on liver biopsy collected from the donor showed that he was actually bearing the homozygous CDA*2 allelic variant (ie, 79AA), a genotype usually associated with severe CDA deficiency. Based upon the donor liver genotype, and not the recipient genotype, treatement was resumed with further dose reduction, close monitoring and better tolerance eventually. The patient is now in complete remission more than a year after completion of the treatment. This case report illustrates the limits and risks of searching germline polymorphisms in patients with liver transplant when the story plays in the liver.

Citation Format: Cindy Serdjebi, Raphaelle Fanciullino, Frederic Fina, Arnaud Verschuur, Bertrand Roquelaure, Bruno Lacarelle, L'Houcine Ouafik, Joseph Ciccolini, Nicolas André. Recipient-donor contradictory genotype with impact on anticancer drug pharmacogenetics after liver transplant: A deadly gift. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5549. doi:10.1158/1538-7445.AM2014-5549

Biodistribution, tumor uptake and efficacy of 5-FU-loaded liposomes: why size matters

PURPOSE

We have investigated the impact of particle size on the biodistribution, tumor uptake and antiproliferative efficacy of 5-FU-loaded liposomes.

METHODS

Three different batches of pegylated liposomes varying in size (i.e., 70, 120 and 250 nm respectively) were tested. The active compounds encapsulated were an equimolar mix of 5-FU, 2'-deoxyinosine and folinic acid. Liposomes were subsequently tested on the human breast cancer model MDA231 cells, a model previously found to be resistant to 5-FU. In vitro, antiproliferative efficacy and microscopy studies of liposomes uptake were carried out. In vivo, comparative biodistribution and efficacy studies were performed in tumor-bearing mice.

RESULTS

Difference in size did not change in vitro antiproliferative activity. Fluorescence-Microscopy studies showed that liposomes were mainly uptaken by tumor cells through a direct internalization process, regardless of their size. Biodistribution profiles in tumor-bearing mice revealed higher accumulation of small liposomes in tumors throughout time as compared with normal and large liposomes (p < 0.05). Additionally, we observed that the bigger were the tumors, the more vascularised they were and the greater was the difference in accumulation between small and large liposomes. Consequently, in vivo efficacy studies showed at study conclusion that a 68% reduction in tumor size was achieved with small liposomes (p < 0.05), whereas larger liposomes failed to reduce significantly tumor growth. Similarly, at study conclusion a trend towards higher survival-rate in animals treated with smaller liposomes was observed.

CONCLUSION

This study suggests that particle size is critical to achieve higher selectivity and efficacy in experimental oncology, including in resistant tumors.

Rapid deaminator status is associated with poor clinical outcome in pancreatic cancer patients treated with a gemcitabine-based regimen

BACKGROUND

Gemcitabine is a mainstay in the treatment of biliary and pancreatic cancers, with limited efficacy in most settings. The gemcitabine elimination pattern is primarily driven by deamination in the liver by CDA. CDA is affected by genetic polymorphisms, leading to marked variations in activity and, subsequently, to erratic drug plasma exposures in patients administered with standard dosage. CDA deficiency has been a rising concern with gemcitabine since several studies have proven that poor metabolizer patients experience life-threatening toxicities upon drug intake. In theory, ultrarapid metabolizer (UM) patients should be conversely at risk of treatment failure, although thus far few studies have addressed this issue in digestive oncology.

PATIENTS & METHODS

A pilot study was conducted on 40 pancreatic cancer patients, all treated with gemcitabine-based therapy. CDA status was primarily established on a phenotypic basis determined by measurement of residual CDA enzymatic activity in serum. Additionally, a search for c208G>A and c79A>C polymorphisms was carried out.

RESULTS

No patients carrying c208G>A polymorphisms were found, and only heterozygous c79A>C patients were observed. Eight out of the 40 patients (i.e., 20%) were identified as UM, with CDA activities over 6 U/mg. CDA activity was significantly different between progressive disease patients and patients with controlled disease (8.4 vs 3 U/mg; p < 0.001). Conversely, fewer gemcitabine-related severe toxicities were observed in UM patients.

CONCLUSION

This pilot study strongly suggests that UM patients are nearly five-times more likely to have progressive disease than patients with normal or low CDA activities, and that beside molecular events at the tumor level, upstream deregulations affecting drug disposition should be taken into account.

Cytidine deaminase status as a predictive marker in patients with hematologic malignancies treated with azacytidine or cytarabine

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Background: Cytarabine and azacytidine are mainstays for treating haematological malignancies. As most nucleosidic analogs, both azacytidine and cytarabine are metabolized in the liver by an exclusive enzymatic step driven by cytidine deaminase (CDA). CDA is highly polymorphic and dysregulations have been repeatedly associated with poor clinical outcome with gemcitabine. Methods: We have used a test to determine, on a phenotype basis, CDA status in patients. This test was used prospectively in a subset of 39 adult patients (16F, 23M, mean age 77 years), all treated for various haematological malignancies (i.e., CML, AML, lymphomas, myelodysplastic syndromes) with either aza-cytidine or a cytarabine-containing regimen. Response and treatment-related toxicities were monitored following current standards. In addition, impact of CDA status on azacytidine tolerance was evaluated in mice with or without CDA deficiency, as a proof of concept for the actual implication of metabolic deregulations in the toxicities observed in patients. Results: In patients, mean CDA activity was 3.7 +/-2.8 U/mg (min: 1, max: 14.8 U/mg). Ten out of 39 patients (i.e., 25%) showed low CDA activities and were considered as PM. Conversely, 8 patients (i.e., 20%) displayed CDA activities particurlary elevated (i.e., > 6U/mg) and were considered as UM patients. Of note, PM patients all showed severe toxicities, including two toxic-deaths. Conversely, UM patients showed little efficacy when treated with either azacytidine or cytarabine. In mice with CDA-deficiency, standard azacytidine led to profound and long-lasting neutropenia, as compared with normal mice. Drug monitoring confirmed that individuals with low CDA activity and toxicities showed higher concentrations of azacytidine as compared with normal individuals. Conclusions: Overall this pilot study strongly suggests that CDA status could be a relevant marker for predicting clinical outcome in patients treated with either azacytidine or cytarabine. CDA status could be further used as a covariate to tailor drug dosage so as to ensure an optimal efficacy/toxicity balance in patients with haematological malignancies.

Abstract 2208: Cytidine deaminase deficiency and severe toxicities upon aza-cytidine intake: Clinical observations and experimental evidences

Azacytidine is a nucleosidic analog used for treating a variety of haematological malignancies. Azacytidine pharmacokinetics is dependent upon a liver detoxification step driven by cytidine deaminase (CDA). CDA is affected by several genetic polymorphisms leading to a wide inter-individual variability in resulting enzymatic activities. In particurlar, dysregulated CDA has been associated with life-threatening toxicities with several nucleosidic analogs such as after cytarabine, capecitabine and gemcitabine intake. However, little is known about the impact of CDA deficiency on the clinical outcome of patients treated with azacytidine. In our institute, a lethal toxicity after pancytopenia has been observed with a 82-years old female patient upon aza-cytidine intake. CDA deficiency was evidenced after retrospective phenotyping (functional activity was found to be reduced by 65% as compared with standard CDA values: 1.2 VS. 3.5 U/mg), thus strongly suggesting that impaired ability to detoxify azacytidine could be the culprit indeed for this case. To further establish the exact role CDA-deficiency could have played in this toxic-death, a non-clinical study was undertaken in rodents. To mimic CDA deficiency, 8 mice were pre-treated with 100 mg/kg of tetrahydrouridine I.P. before being administered with 24 mg/kg of azacytidine. Another group of 8 mice received 24 mg/kg azacytidine only, and were therefore considered as control-CDA. Four mice were used as untreated controls when evaluating tolerance to the treatment. Neutrophils were monitored by flow-cytometry before and after treatment over 10 days as a surrogate marker for global azacytidine-related toxicities. CDA was measured using the same test than the one used at bedside and showed that the two groups differed markedly in their CDA phenotypes (ie, 7.7 VS. 0.98 U/mg) and that deep CDA deficiency (Poor Metabolizer: PM status) was achieved indeed in THU-treated animals. Pharmacokinetics study was carried out on a satellite group (T10, T20, T40 and T60 min) by revered-phase HPLC-UV analysis and showed a marked overexposure in azacytidine plasma levels in PM animals displaying CDA-deficiency. In full line with this observation, longer and deeper neutropenia was observed in this PM subset, as compared with the mice with normal CDA activity treated with the same dosage of azacytidine. Overall, our experimental data strongly support the hypothesis that CDA deficiency is a condition associated with increased risk to undergo life-threatening toxicities after azacytidine treatment. Detecting PM patients should help to secure the use of azacytidine at bedside.

Citation Format: Raphaelle Fanciullino, Cindy Serdjebi, Severine Mollard, Regis Costello, L'Houcine Ouafik, Joseph Ciccolini, Cedric Mercier. Cytidine deaminase deficiency and severe toxicities upon aza-cytidine intake: Clinical observations and experimental evidences. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2208. doi:10.1158/1538-7445.AM2013-2208