A. Anitha

Combinatorial anticancer effects of curcumin and 5-fluorouracil loaded thiolated chitosan nanoparticles towards colon cancer treatment

BACKGROUND Evaluation of the combinatorial anticancer effects of curcumin/5-fluorouracil loaded thiolated chitosan nanoparticles (CRC-TCS-NPs/5-FU-TCS-NPs) on colon cancer cells and the analysis of pharmacokinetics and biodistribution of CRC-TCS-NPs/5-FU-TCS-NPs in a mouse model. METHODS CRC-TCS-NPs/5-FU-TCS-NPs were developed by ionic cross-linking. The in vitro combinatorial anticancer effect of the nanomedicine was proven by different assays. Further the pharmacokinetics and biodistribution analyses were performed in Swiss Albino mouse using HPLC. RESULTS The 5-FU-TCS-NPs (size: 150±40nm, zeta potential: +48.2±5mV) and CRC-TCS-NPs (size: 150±20nm, zeta potential: +35.7±3mV) were proven to be compatible with blood. The in vitro drug release studies at pH4.5 and 7.4 showed a sustained release profile over a period of 4 days, where both the systems exhibited a higher release in acidic pH. The in vitro combinatorial anticancer effects in colon cancer (HT29) cells using MTT, live/dead, mitochondrial membrane potential and cell cycle analysis measurements confirmed the enhanced anticancer effects (2.5 to 3 fold). The pharmacokinetic studies confirmed the improved plasma concentrations of 5-FU and CRC up to 72h, unlike bare CRC and 5-FU. CONCLUSIONS To conclude, the combination of 5-FU-TCS-NPs and CRC-TCS-NPs showed enhanced anticancer effects on colon cancer cells in vitro and improved the bioavailability of the drugs in vivo. GENERAL SIGNIFICANCE The enhanced anticancer effects of combinatorial nanomedicine are advantageous in terms of reduction in the dosage of 5-FU, thereby improving the chemotherapeutic efficacy and patient compliance of colorectal cancer cases.

Curcumin-Loaded N,O-Carboxymethyl Chitosan Nanoparticles for Cancer Drug Delivery

Abstract Chitosan (CS) and its carboxymethyl derivatives are smart biopolymers that are non-toxic, biocompatible and biodegradable, and, hence, suitable for various biomedical applications, such as drug delivery, gene therapy and tissue engineering. Curcumin is a major chemotherapeutic agent with antioxidant, anti-inflammatory, anti-proliferative, anticancer and antimicrobial effects. However, the potential of curcumin as a chemotherapeutic agent is limited by its hydrophobicity and poor bioavailability. In this work, we developed a nanoformulation of curcumin in a carboxymethyl chitosan (CMC) derivative, N,O-carboxymethyl chitosan (N,O-CMC). The curcumin-loaded N,O-CMC (curcumin-N,O-CMC) nanoparticles were characterized using DLS, AFM, SEM, FT-IR and XRD. DLS studies revealed nanoparticles with a mean diameter of 150 ± 30 nm. AFM and SEM confirmed that the particles have a spherical morphology within the size range of 150 ± 30 nm. Curcumin was entrapped with in N,O-CMC nanopartcles with an efficiency of 80%. The in vitro drug-release profile was studied at different pH (7.4 and 4.5) at 37°C for different incubation periods with and without lysozyme. Cytotoxicity studies using MTT assay indicated that curcumin-N,O-CMC nanoparticles showed specific toxicity towards cancer cells and non-toxicity to normal cells. Cellular uptake of curcumin-N,O-CMC nanoparticles was analyzed by fluorescence microscopy and was reconfirmed by flow cytometry. Overall, these results indicate that like previously reported curcumin loaded O-CMC nanoparticles, N,O-CMC will also be an efficient nanocarrier for delivering curcumin to cancer cells.

In vitro combinatorial anticancer effects of 5-fluorouracil and curcumin loaded N,O-carboxymethyl chitosan nanoparticles toward colon cancer and in vivo pharmacokinetic studies

Colon cancer is the third most leading causes of death due to cancer worldwide and the chemo drug 5-fluorouracils (5-FU) applicability is limited due to its non-specificity, low bioavailability and overdose. The efficacy of 5-FU in colon cancer chemo treatment could be improved by nanoencapsulation and combinatorial approach. In the present study curcumin (CUR), a known anticancer phytochemical, was used in combination with 5-FU and the work focuses on the development of a combinatorial nanomedicine based on 5-FU and CUR in N,O-carboxymethyl chitosan nanoparticles (N,O-CMC NPs). The developed 5-FU-N,O-CMC NPs and CUR-N,O-CMC NPs were found to be blood compatible. The in vitro drug release profile in pH 4.5 and 7.4 showed a sustained release profile over a period of 4 days. The combined exposure of the nanoformulations in colon cancer cells (HT 29) proved the enhanced anticancer effects. In addition, the in vivo pharmacokinetic data in mouse model revealed the improved plasma concentrations of 5-FU and CUR which prolonged up to 72 h unlike the bare drugs. In conclusion, the 5-FU and CUR released from the N,O-CMC NPs produced enhanced anticancer effects in vitro and improved plasma concentrations under in vivo conditions.

In vitro evaluation of paclitaxel loaded amorphous chitin nanoparticles for colon cancer drug delivery.

Chitin and its derivatives have been widely used in drug delivery applications due to its biocompatible, biodegradable and non-toxic nature. In this study, we have developed amorphous chitin nanoparticles (150±50 nm) and evaluated its potential as a drug delivery system. Paclitaxel (PTX), a major chemotherapeutic agent was loaded into amorphous chitin nanoparticles (AC NPs) through ionic cross-linking reaction using TPP. The prepared PTX loaded AC NPs had an average diameter of 200±50 nm. Physico-chemical characterization of the prepared nanoparticles was carried out. These nanoparticles were proven to be hemocompatible and in vitro drug release studies showed a sustained release of PTX. Cellular internalization of the NPs was confirmed by fluorescent microscopy as well as by flow cytometry. Anticancer activity studies proved the toxicity of PTX-AC NPs toward colon cancer cells. These preliminary results indicate the potential of PTX-AC NPs in colon cancer drug delivery.

In vitro and in vivo evaluation of osteoporosis therapeutic peptide PTH 1-34 loaded pegylated chitosan nanoparticles.

Oral formulation of human parathyroid hormone 1-34 (PTH 1-34) is an alternative patient compliant route in treating osteoporosis. PTH 1-34 loaded chitosan nanoparticles were PEGylated (PEG-CS-PTH NPs) and characterized by DLS, SEM, TEM and FTIR. PEG-CS-PTH NP aggregates of 200-250 nm which in turn comprised 20 nm individual nanoparticles were observed in SEM and TEM images respectively. The PEG-CS-PTH NP with 40% encapsulation efficiency was subjected to an in vitro release in simulated rat body fluids. PEG-CS-PTH NP treated human primary osteoblast cells, upon PTH 1-34 receptor activation, produced second messenger-cAMP, which downstream stimulated intracellular calcium uptake, production of bone specific alkaline phosphatase, osteocalcin etc., which substantiates the anabolic effect of the peptide. PEG-CS-PTH NPs showed an oral bioavailability of 100-160 pg/mL PTH 1-34 throughout 48 h, which is remarkable compared to the bare PTH 1-34 and CS-PTH NPs. The NIR image of gastrointestinal transit of ICG conjugated PEG-CS-PTH NPs supports this significant finding.

Relevance of fiber integrated gelatin-nanohydroxyapatite composite scaffold for bone tissue regeneration

Porous nanohydroxyapatite (nanoHA) is a promising bone substitute, but it is brittle, which limits its utility for load bearing applications. To address this issue, herein, biodegradable electrospun microfibrous sheets of poly(L-lactic acid)-(PLLA)-polyvinyl alcohol (PVA) were incorporated into a gelatin-nanoHA matrix which was investigated for its mechanical properties, the physical integration of the fibers with the matrix, cell infiltration, osteogenic differentiation and bone regeneration. The inclusion of sacrificial fibers like PVA along with PLLA and leaching resulted in improved cellular infiltration towards the center of the scaffold. Furthermore, the treatment of PLLA fibers with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide enhanced their hydrophilicity, ensuring firm anchorage between the fibers and the gelatin-HA matrix. The incorporation of PLLA microfibers within the gelatin-nanoHA matrix reduced the brittleness of the scaffolds, the effect being proportional to the number of layers of fibrous sheets in the matrix. The proliferation and osteogenic differentiation of human adipose-derived mesenchymal stem cells was augmented on the fibrous scaffolds in comparison to those scaffolds devoid of fibers. Finally, the scaffold could promote cell infiltration, together with bone regeneration, upon implantation in a rabbit femoral cortical defect within 4 weeks. The bone regeneration potential was significantly higher when compared to commercially available HA (Surgiwear™). Thus, this biomimetic, porous, 3D composite scaffold could be offered as a promising candidate for bone regeneration in orthopedics.

Combinatorial nanomedicines for colon cancer therapy.

Colon cancer is one of the major causes of cancer deaths worldwide. Even after surgical resection and aggressive chemotherapy, 50% of colorectal carcinoma patients develop recurrent disease. Thus, the rationale of developing new therapeutic approaches to improve the current chemotherapeutic regimen would be highly recommended. There are reports on the effectiveness of combination chemotherapy in colon cancer and it has been practiced in clinics for long time. These approaches are associated with toxic side effects. Later, the drug delivery research had shown the potential of nanoencapsulation techniques and active targeting as an effective method to improve the effectiveness of chemotherapy with less toxicity. This current focus article provides a brief analysis of the ongoing research in the colon cancer area using the combinatorial nanomedicines and its outcome.

Bioinspired Composite Matrix Containing Hydroxyapatite–Silica Core–Shell Nanorods for Bone Tissue Engineering

Development of multifunctional bioinspired scaffolds that can stimulate vascularization and regeneration is necessary for the application in bone tissue engineering. Herein, we report a composite matrix containing hydroxyapatite (HA)-silica core-shell nanorods with good biocompatibility, osteogenic differentiation, vascularization, and bone regeneration potential. The biomaterial consists of a crystalline, rod-shaped nanoHA core with uniform amorphous silica sheath (Si-nHA) that retains the characteristic phases of the individual components, confirmed by high-resolution transmission electron microscopy, X-ray diffractometer, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The nanorods were blended with gelatinous matrix to develop as a porous, composite scaffold. The viability and functionality of osteogenically induced mesenchymal stem cells as well as endothelial cells have been significantly improved through the incorporation of Si-nHA within the matrix. Studies in the chicken chorioallantoic membrane and rat models demonstrated that the silica-containing scaffolds not only exhibit good biocompatibility, but also enhance vascularization in comparison to the matrix devoid of silica. Finally, when tested in a critical-sized femoral segmental defect in rats, the nanocomposite scaffolds enhanced new bone formation in par with the biomaterial degradation. In conclusion, the newly developed composite biomimetic scaffold may perform as a promising candidate for bone tissue engineering applications.

BMP2 Expressing Genetically Engineered Mesenchymal Stem Cells on Composite Fibrous Scaffolds for Enhanced bone Regeneration in Segmental Defects

The treatment of critical sized bone defect remains a significant challenge in orthopedics. The objective of the study is to evaluate the effect of the combination of bone morphogenetic protein 2 (BMP2) expressing genetically engineered mesenchymal stem cells (MSCs) [MSCs engineered using a multimam vector, pAceMam1, an emerging gene delivery vector] and an osteoconductive scaffold [silica coated nanohydroxyapatite-gelatin reinforced with fibers] in enhancing bone regeneration in critical sized segmental defects. The scaffold with transfected MSCs showed significantly higher viability, proliferation and osteogenic differentiation in vitro. Further, this group augmented union and new bone formation in critical sized rat femoral segmental defect at 12 weeks when compared to control groups (scaffold with MSCs and scaffold alone). These data demonstrated that the MSCs engineered for transient expression of BMP2 can improve the repair of segmental defects, which paves an avenue for using pAceMam1 as a vector for bone tissue regeneration.