To explore the intercalating mechanism of β-carbolines, four novel N-(3-carboxyl-9-benzylcarboline-1-yl)ethylamino acids [-phenylalanine (6a), -alanine (6b), -isoleucine (6c) and -glycine (6d)] were prepared here. Their in vitro anticancer activities were examined by their anti-proliferation for 5 human carcinoma cell lines. The average IC₅₀s against 5 human carcinoma cell lines are 53.54 µM, 118.77 µM, 147.34 µM and greater than 291.63 µM for 6a, 6b, 6c and 6d, respectively. The DNA intercalating mechanism of 6a–d was approved by the comparison of the parameters and signals of UV, CD and fluorescence spectra of calf thymus DNA (CT DNA) alone and the CT DNA/6a–d system. Using fluorescence titration based kinetic analysis a two-step-course consisting of stacking and intercalating was described and the stacking was considered as the key step to the CT DNA intercalating mechanism of 6a–d. Using fluorescence titration based thermomechanical analysis, the stacking complexes of 6a–d with CT DNA were described to be formed spontaneously and to be stabilized predominantly by their hydrophobic interactions. The intercalation itself goes very fast and only has limited contribution to their anticancer activities.

In the treatment of cancer patients, cisplatin (CDDP) exhibits serious cardiac and renal toxicities, while classical combinations related to CDDP are unable to solve these problems and may result in worse prognosis. Alternately, this study covalently conjugated 6-mercaptopurine (6MP) onto the surface of mercapto-modified mesoporous silica nanoparticles (MSNS) to form MSNS-6MP and loaded CDDP into the holes on the surface of MSNS-6MP to form MSNS-6MP/CDDP, a tumor-targeting nano-releasing regime for CDDP and 6MP specifically. In the S180 mouse model, the anti-tumor activity and overall survival of MSNS-6MP/CDDP (50 mg·kg^-1·day^-1, corresponding to 1 mg·kg^-1·day^-1 of 6MP and 5 mg·kg^-1·day^-1 of CDDP) were significantly higher than those of CDDP alone (5 mg·kg^-1·day^-1) or CDDP (5 mg·kg^-1·day^-1) plus 6MP (1 mg·kg^-1·day^-1). The assays of serum alanine aminotransferase, aspartate aminotransferase and creatinine, as well as the images of myocardium and kidney histology, support that MSNS-6MP/CDDP is able to completely eliminate liver, kidney and heart toxicities induced by CDDP alone or CDDP plus 6MP.

A simple one-pot multi-component ROMP of hydrophilic, spiropyran (SP) and tert-butyloxycarbonyl-protected (Boc-protected) amino-functionalized norbornenes was developed, and a series of water-soluble copolymeric materials were provided. The photochromic SP moiety endows the copolymers the properties of switchable fluorescence imaging with alternating near-IR (NIR) two-photon and visible single-photon excitations; thereby the copolymers can serve as a promising NIR two-photon fluorescent probe for living cancer cells. The cationic ammonium group enhances the cell transporting capability of the copolymers as well. The present strategy of one-pot ROMP also makes polynorbornene a modular and flexible scaffold in designing and synthesizing specifically biocompatible polymers with applications in imaging, diagnosis and therapy.