3 research outputs found
Development of an Efficient in Vitro Regeneration System for Endangered Wild Orange Citrus Chrysocarpa L.
A method for in-vitro propagation of wild type Indian orange (Citrus chrysocarpa L.) was developed by shoot organogenesis from seed. Mature seed embryos were used as explants and treated with different hormones and plant growth regulators on MS medium for callus, shoots and roots induction. For callus inductio
PEG Linker Length Strongly Affects Tumor Cell Killing by PEGylated Carbonic Anhydrase Inhibitors in Hypoxic Carcinomas Expressing Carbonic Anhydrase IX
Hypoxic tumors overexpress membrane-bound isozymes of carbonic anhydrase (CA) CA IX and CA XII, which play key roles in tumor pH homeostasis under hypoxia. Selective inhibition of these CA isozymes has the potential to generate pH imbalances that can lead to tumor cell death. Since these isozymes are dimeric, we designed a series of bifunctional PEGylated CA inhibitors (CAIs) through the attachment of our preoptimized CAI warhead 1,3,4-thiadiazole-2-sulfonamide to polyethylene glycol (PEG) backbones with lengths ranging from 1 KDa to 20 KDa via a succinyl linker. A detailed structure−thermal properties and structure–biological activity relationship study was conducted via differential scanning calorimetry (DSC) and via viability testing in 2D and 3D (tumor spheroids) cancer cell models, either CA IX positive (HT-29 colon cancer, MDA-MB 231 breast cancer, and SKOV-3 ovarian cancer) or CA IX negative (NCI-H23 lung cancer). We identified PEGylated CAIs DTP1K 28, DTP2K 23, and DTP3.4K 29, bearing short and medium PEG backbones, as the most efficient conjugates under both normoxic and hypoxic conditions, and in the tumor spheroid models. PEGylated CAIs did not affect the cell viability of CA IX-negative NCI-H23 tumor spheroids, thus confirming a CA IX-mediated cell killing for these potential anticancer agents
pH-Sensitive Multiligand Gold Nanoplatform Targeting Carbonic Anhydrase IX Enhances the Delivery of Doxorubicin to Hypoxic Tumor Spheroids and Overcomes the Hypoxia-Induced Chemoresistance
Hypoxia
is a common feature of solid tumors
contributing to resistance to chemotherapy. Selective delivery of
chemotherapeutic drugs to hypoxic tumor niche remains an unsolved
issue. For this purpose, we constructed a gold nanoplatform targeting
carbonic anhydrase IX (CA IX) epitope, which is overexpressed in hypoxic
tumor cells versus in normal tissues. We designed compatible low-molecular
weight carbonic anhydrase inhibitor (CAI) ligands and doxorubicin
(Dox) ligands and optimized protocols for efficient decoration of
gold nanoparticles (Au NPs) to achieve both good targeting ligand
density and optimum drug loading, while preserving colloidal stability.
The optimized Dox-HZN-DTDP@Au NPs-LA-PEG2000-CAI (THZN) nanoplatform
was proved to be very efficient toward killing HT-29 tumor cells,
especially under hypoxic conditions, as compared with the nontargeting
nanoplatform. This also mediated the effective release of doxorubicin
in the lysosomes following internalization, as revealed by confocal
microscopy. Furthermore, using tumor spheroids as a representative
model for hypoxic solid tumors, our THZN nanoplatform enhanced the
selective delivery of doxorubicin up to 2.5 times and minimized chemoresistance,
showing better tumor drug penetration as compared to that in free drug
treatment. Our technology is the first CA IX-targeting gold nanoplatform
for efficient delivery of doxorubicin to hypoxic tumors in a controlled
fashion, with the perspective to improve the therapy of solid tumors
and minimize chemoresistance