The potential of celecoxib-loaded hydroxyapatite-chitosan nanocomposite for the treatment of colon cancer

Poly(styrene-co-maleic acid)-based pH-sensitive liposomes mediate cytosolic delivery of drugs for enhanced cancer chemotherapy

pH-responsive polymers render liposomes pH-sensitive and facilitate the intracellular release of encapsulated payload by fusing with endovascular membranes under mildly acidic conditions found inside cellular endosomes. The present study reports the use of high-molecular weight poly(styrene-co-maleic acid) (SMA), which exhibits conformational transition from a charged extended structure to an uncharged globule below its pK(1) value, to confer pH-sensitive property to liposomes. The changes in the co-polymer chain conformation resulted in destabilization of the liposomes at mildly acidic pH due to vesicle fusion and/or channel formation within the membrane bilayer, and ultimately led to the release of the encapsulated cargo. The vesicles preserved their pH-sensitivity and stability in serum unlike other polymer-based liposomes and exhibited no hemolytic activity at physiological pH. The lysis of RBCs at endosomal pH due to SMA-based liposome-induced alterations in the bilayer organization leading to spherocyte formation indicated the potential of these vesicles to mediate cytosolic delivery of bio-active molecules through endosome destabilization. The SMA-loaded liposomes exhibiting excellent cytocompatibility, efficiently delivered chemotherapeutic agent 5-Fluorouracil (5-FU) within colon cancer cells HT-29 in comparison to neat liposomes. This caused increased cellular-availability of the drug, which resulted in enhanced apoptosis and highlighted the clinical potential of SMA-based vesicles.

Recent advances in research applications of nanophase hydroxyapatite

Hydroxyapatite, the main inorganic material in natural bone, has been used widely for orthopaedic applications. Due to size effects and surface phenomena at the nanoscale, nanophase hydroxyapatite possesses unique properties compared to its bulk-phase counterpart. The high surface-to-volume ratio, reactivities, and biomimetic morphologies make nano-hydroxyapatite more favourable in applications such as orthopaedic implant coating or bone substitute filler. Recently, more efforts have been focused on the possibility of combining hydroxyapatite with other drugs and materials for multipurpose applications, such as antimicrobial treatments, osteoporosis treatments and magnetic manipulation. To build more effective nano-hydroxyapatite and composite systems, the particle synthesis processes, chemistry, and toxicity have to be thoroughly investigated. In this Minireview, we report the recent advances in research regarding nano-hydroxyapatite. Synthesis routes and a wide range of applications of hydroxyapatite nanoparticles will be discussed. The Minireview also addresses several challenges concerning the biosafety of the nanoparticles.

Observation of Curative Efficacy and Prognosis following Combination Chemotherapy with Celecoxib in the Treatment of Advanced Colorectal Cancer

This study investigated the antitumour and chemosensitizing effects of celecoxib in the treatment of advanced colorectal cancer. A total of 90 patients were randomly divided into two groups: group CF was treated with a combination of celecoxib and the folinic acid-fluorouracil-oxaliplatin (FOLFOX4) regimen; and group F was treated with the FOLFOX4 regimen alone. Immunohistochemical analysis of tumour tissues for cyclooxygenase-2 (COX-2) protein was performed. With regard to short-term efficacy, the response and disease control rates were significantly greater in group CF than group F. A log-rank test showed that the 3-year survival rate was significantly greater in group CF than group F. It was concluded that the addition of celecoxib to the FOLFOX4 regimen increased the short-term efficacy and the 3-year survival rate, and improved the quality of life of patients with advanced colorectal cancer. The antitumour and chemosensitizing effects of celecoxib appeared to be independent of COX-2.