Novel Gemcitabine Conjugated Albumin Nanoparticles: a Potential Strategy to Enhance Drug Efficacy in Pancreatic Cancer Treatment

Purpose: The present study reports a novel conjugate of gemcitabine (GEM) with bovine serum albumin (BSA) and thereof nanoparticles (GEM-BSA NPs) to potentiate the therapeutic efficacy by altering physicochemical properties, improving cellular uptake and stability of GEM. Methods: The synthesized GEM-BSA conjugate was extensively characterized by NMR, FTIR, MALDI-TOF and elemental analysis. Conjugation mediated changes in structural conformation and physicochemical properties were analysed by fluorescence, Raman and CD spectroscopy, DSC and contact angle analysis. Further, BSA nanoparticles were developed from BSA-GEM conjugate and extensively evaluated against in-vitro pancreatic cancer cell lines to explore cellular uptake pathways and therapeutic efficacy. Results: Various characterization techniques confirmed covalent conjugation of GEM with BSA. GEM-BSA conjugate was then transformed into NPs via high pressure homogenization technique with particle size 147.2 ± 7.3, PDI 0.16 ± 0.06 and ZP -19.2 ± 1.4. The morphological analysis by SEM and AFM revealed the formation of smooth surface spherical nanoparticles. Cellular uptake studies in MIA PaCa-2 (GEM sensitive) and PANC-1 (GEM resistant) pancreatic cell lines confirmed energy dependent clathrin internalization/endocytosis as a primary mechanism of NPs uptake. In-vitro cytotoxicity studies confirmed the hNTs independent transport of GEM in MIA PaCa-2 and PANC-1 cells. Moreover, DNA damage and annexin-V assay revealed significantly higher apoptosis level in case of cells treated with GEM-BSA NPs as compared to free GEM. Conclusions: GEM-BSA NPs were found to potentiate the therapeutic efficacy by altering physicochemical properties, improving cellular uptake and stability of GEM and thus demonstrated promising therapeutic potential over free drug

Lethal toxicity after administration of azacytidine:implication of the cytidine deaminase-deficiency syndrome.

International audienceAzacytidine, an antimetabolite with an original epigenetic mechanism of action, increases survival in patients diagnosed with high-risk myelodysplasic syndromes or acute myeloid leukemia with less than 30% medullar blasts. Azacytidine is a pyrimidine derivative that undergoes metabolic detoxification driven by cytidine deaminase (CDA), a liver enzyme whose gene is prone to genetic polymorphism, leading to erratic activity among patients. Clinical reports have shown that patients with the poor metabolizer (PM) phenotype are likely to experience early severe or lethal toxicities when treated with nucleosidic analogs such as gemcitabine or cytarabine. No clinical data have been available thus far on the relationships between CDA PM status and toxicities in azacytidine-treated patients. Here, we measured CDA activity in a case of severe toxicities with fatal outcome in a patient undergoing standard azacytidine treatment. Results showed that the patient was PM (i.e. residual activity reduced by 63%), thus suggesting that an impaired detoxification step could have given rise to the lethal toxicities observed. This case report calls for further prospective studies investigating the exact role that CDA status plays in the clinical outcome of patients treated with azacytidine

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

International audienceAzacitidine 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

Meeting Abstract: 745P

International audienc

Meeting Abstract: 745P

International audienc

Acceleration of clear cell renal cell carcinoma growth in mice following bevacizumab/Avastin treatment: the role of CXCL cytokines.

International audienceThe anti-VEGF targeted antibody bevacizumab (BVZ) has been approved for treating renal cell carcinomas (RCCs). Although BVZ increases the progression-free survival of patients with metastatic RCC, the effect on overall survival is poor. To gain insight into the limited efficacy of BVZ on overall survival, we analyzed patient samples of RCC for angiogenic factors that may participate in escape from anti-VEGF therapy. Our study shows that the level of vascular endothelial growth factor (VEGF) in tumors was increased compared with normal tissue. The level of interleukin-8/CXCL8, a pro-angiogenic member of the CXCL family of cytokines, was also increased in tumors. These observations gave us a good reason to analyze the combined effects of BVZ and anti-CXCL8 antibodies on tumor growth. Surprisingly, we report that BVZ accelerates the growth of RCC in nude mice with in vivo selection of tumor cells with an increased growth capacity. Downregulation of receptor tyrosine phosphatase-κ, a phosphatase implicated in EGF receptor regulation, may partly explain this phenomenon. Modification of the vascular network and development of lymphatic vessels through VEGF-C production and compensatory production of pro-angiogenic CXCL cytokines were also observed. The apparent normalization of the vascular network prompted us to associate BVZ with the chemotherapeutic agent paclitaxel. While efficient in vitro, paclitaxel did not reverse the anti-VEGF effects in vivo. Anti-CXCL8-targeting antibodies were promising as they decreased intra-tumor VEGF production; decreased the pro-angiogenic CXCL/anti-angiogenic CXCL ratio and did not induce lymphangiogenesis. These observations hold clinical implication as they highlight putative markers implicated in escape from BVZ treatment. They also recommend proceeding with caution in the use of anti-VEGF therapy alone for treatment of RCC