Anticancer activity of drug conjugates in head and neck cancer cells.

Sexually transmitted oral cancer/head and neck cancer is increasing rapidly. Human papilloma virus (HPV) is playing a role in the pathogenesis of a subset of squamous cell carcinoma of head and neck (SCCHN). Paclitaxel is a widely used anticancer drug for breast, ovarian, testicular, cervical, non-small cell lung, head and neck cancer. However, it is water insoluble and orally inactive. We report the synthesis of water soluble nanosize conjugates of paclitaxel, branched PEG, and EGFR-targeting peptide by employing native chemical ligation. We performed a native chemical ligation between the N-hydroxy succinimide (NHS) ester of paclitaxel succinate and cysteine at pH 6.5 to give the cysteine-conjugated paclitaxel derivative. The thiol functionality of cysteine was activated and subsequently conjugated to multiarm thiol-PEG to obtain the paclitaxel branched PEG conjugate. Finally, we conjugated an EGFR-targeting peptide to obtain conjugates of paclitaxel, branched PEG, and EGFR-targeting peptide. These conjugates show anticancer activity against squamous cell carcinoma of head and neck cells (SCCHN, Tu212).

Luteolin nanoparticle in chemoprevention: in vitro and in vivo anticancer activity.

Cancer prevention (chemoprevention) by using naturally occurring dietary agents has gained immense interest because of the broad safety window of these compounds. However, many of these compounds are hydrophobic and poorly soluble in water. They frequently display low bioavailability, poor systemic delivery, and low efficacy. To circumvent this problem, we explored a novel approach toward chemoprevention using nanotechnology to deliver luteolin, a natural compound present in green vegetables. We formulated water-soluble polymer-encapsulated Nano-Luteolin from hydrophobic luteolin, and studied its anticancer activity against lung cancer and head and neck cancer. In vitro studies demonstrated that, like luteolin, Nano-Luteolin inhibited the growth of lung cancer cells (H292 cell line) and squamous cell carcinoma of head and neck (SCCHN) cells (Tu212 cell line). In Tu212 cells, the IC50 value of Nano-Luteolin was 4.13 µmol/L, and that of luteolin was 6.96 µmol/L. In H292 cells, the IC50 of luteolin was 15.56 µmol/L, and Nano-Luteolin was 14.96 µmol/L. In vivo studies using a tumor xenograft mouse model demonstrated that Nano-Luteolin has a significant inhibitory effect on the tumor growth of SCCHN in comparison to luteolin. Our results suggest that nanoparticle delivery of naturally occurring dietary agents like luteolin has many advantages and may have potential application in chemoprevention in clinical settings.

Medicinal chemistry and nanomedicine for reproductive cancer therapeutics.

Nanomedicine is an interdisciplinary research field where chemistry, physics, biology, engineering, nanotechnology, and medicine meet one other. Many novel nanoparticles have been designed, synthesized, and evaluated for selective targeting of cancer cells, delivering, and releasing the anticancer drugs in a controlled manner. In this review article we discuss the current status and future prospects of medicinal chemistry of nanomedicine with particular attention to nanoparticle systems that are in various stages of development for cancer therapy in reproductive medicine.

The medicinal chemistry of theragnostics, multimodality imaging and applications of nanotechnology in cancer.

Targeted imaging of cancer is crucial to modern-day cancer management. This review summarizes the current status and future prospects of targeted cancer imaging with MRI, PET, SPECT, CT, and optical imaging techniques. It describes various approaches of cancer imaging and therapy, based on targeting of integrins, somatostatin receptor, epidermal growth factor receptor (EGFR), Her-2/neu receptor, glucose transporter (GLUT), folate receptor, steroid receptor. It also discusses the applications of nanotechnology in imaging and therapy of cancer. Techniques for imaging of cancer in multiple modalities, using a single agent in a single session, have been developed, and this technique is known as 'multimodality imaging'. In order to develop target-specific imaging probes, various targeting ligands, such as small molecules, antibodies, peptides and aptamers have been used. These new imaging agents will help to develop cancer imaging probes that are highly target specific, biocompatible, have high sensitivity, give high signal to noise ratio, and have optimum pharmacokinetic and pharmacodynamic profiles. In another approach, novel agents have been synthesized, suitable for use in imaging as well as in therapy, and they are known as 'theragnostic (or theranostic) agents'. Multidisciplinary approaches and collaborative research efforts from chemists, biologists, biomedical engineers, pharmaceutical scientists, and medical doctors will lead to the discovery of clinically useful imaging and therapeutic agents that can diagnose, prevent, and cure cancer.

Synthesis of isopeptide epoxide peptidomimetics.

Two epoxide-containing peptidomimetics of the isopeptide, glutamyl-gamma-glutamate, have been synthesized via a route that should be generally applicable to the synthesis of isopeptide analogues in which an oxirane replaces the scissile peptide bond. Enzymes that catalyze the hydrolysis of peptides and isopeptides are often susceptible to inactivation by electrophilic substrate analogues. In this research, an epoxide was installed as an electrophilic replacement of the scissile isopeptide bond. The C-terminal glutamyl mimic was accessed by the stereospecific synthesis of suitably substituted cyclopentenes, 8 and 10, as surrogates for either the L- or D-enantiomer. The enantiomeric cyclopentenes were further elaborated to incorporate an appended sulfone that was reacted with a suitably protected glutamyl-gamma-semialdehyde in a Julia-Kocienski olefination reaction. This olefination afforded predominantly the desired E-olefin isosteres of L-glutamyl-gamma-D-glutamate and L-glutamyl-gamma-L-glutamate, following which peracid-mediated epoxidation and deprotection provided the epoxide-containing peptidomimetics, 4 and 5.

Synthesis of proteophosphoglycans of Leishmania major and Leishmania mexicana.

A novel approach for the synthesis of various fragments of proteophosphoglycans from Leishmania major and Leishmania mexicana proteophosphoglycans has been developed. These compounds have been obtained by coupling alpha-mannosyl and alpha-N-acetyl-glucosamine phosphoramidite derivatives with the serine hydroxyl of various amino acids and peptides to give, after oxidation with tert-BuOOH, phosphotriesters exclusively as alpha-anomers in good yield. The resulting compounds could be deblocked using conventional methods. Glycophosphorylation of preassembled and properly protected peptides was found to be more efficient for the preparation of proteophosphoglycan fragments than a building block approach strategy using a phosphoglycosylserine derivative.

Synthesis of oligosaccharides on soluble high-molecular-weight branched polymers in combination with purification by nanofiltration.

[structure: see text] An efficient approach for polymer-supported oligosaccharide synthesis is described whereby branched and high-molecular-weight PEG derivatives are used in combination with purification by nanofiltration. This methodology was applied to the preparation of a tetraglucoside and the tumor-associated antigen Le(x).