Involvement of target gene polymorphisms in 5-Fluorouracil toxicity: a case report

Matched-pair, 86Y/90Y-labeled, bivalent RGD/bombesin antagonist, [RGD-Glu-[DO3A]-6-Ahx-RM2], as a potential theranostic agent for prostate cancer

INTRODUCTION

In this study, we describe development of a true matched-pair theranostic agent that is able to target the αVβ3 integrin and the gastrin releasing peptide receptor (GRPR). We herein describe methods to metallate and characterize the new conjugate and to validate its biological efficacy by in vitro and in vivo methods.

METHODS

We have previously described the development of [RGD-Glu-6Ahx-RM2] (where RGD: Arg-Gly-Asp; Glu: glutamic acid; 6-Ahx: 6-amino hexanoic acid; RM2: (D-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH2)) that has been conjugated to a DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) bifunctional chelating agent (BFCA) to afford [RGD-Glu-[DO3A]-6-Ahx-RM2] peptide. In this study, we have radiolabeled [RGD-Glu-[DO3A]-6-Ahx-RM2] peptide with 86Y or 90Y. Natural-metallated (natY) conjugates were assessed for binding affinity for the αVβ3 integrin or GRPR in human glioblastoma U87-MG and prostate PC-3 cell lines, respectively. The effective stability of the new tracers was also evaluated prior to in vivo evaluation in normal CF-1 mice and SCID mice bearing xenografted tumors.

RESULTS

Competitive displacement binding assays in PC-3 cells showed high binding affinity for the GRPR (IC50, 5.65 ± 0.00 nM). On the other hand, competitive displacement binding assays in U87-MG cells revealed only moderate binding to the αVβ3 integrin (IC50, 346 ± 5.30 nM). Biodistribution studies in PC-3 tumor-bearing mice [RGD-Glu-[[90Y]Y-DO3A]-6-Ahx-RM2] showed high tumor uptake (8.70 ± 0.35%ID/g at 1 h post-intravenous injection) and retention of tracer (5.28 ± 0.12%ID/g) at 24 h post-intravenous injection. Micro-positron emission tomography (microPET) in PC-3 tumor-bearing mice using [RGD-Glu-[[86Y]Y-DO3A]-6-Ahx-RM2] correlated well with biodistribution investigations over the various time points that were studied.

CONCLUSIONS

The [RGD-Glu-[[86Y]Y-DO3A]-6-Ahx-RM2] and [RGD-Glu-[[90Y]Y-DO3A]-6-Ahx-RM2] matched-pair conjugates described herein exhibit favorable microPET and pharmacokinetic profiles and merit further investigations for molecular imaging and/or therapeutic evaluation in larger animal models and potentially humans.

ADVANCES IN KNOWLEDGE AND IMPLICATIONS FOR PATIENT CARE

The theranostic, heterobivalent, agents described herein perform comparably with other mono- and multivalent conjugates we have reported and offer the potential of improved sensitivity for detecting prostate cancer cells that might exhibit differing profiles of receptor expression on tumor cells in human patients.

Strategy for chemotherapeutic delivery using a nanosized porous metal-organic framework with a central composite design

BACKGROUND

Enhancing drug delivery is an ongoing endeavor in pharmaceutics, especially when the efficacy of chemotherapy for cancer is concerned. In this study, we prepared and evaluated nanosized HKUST-1 (nanoHKUST-1), nanosized metal-organic drug delivery framework, loaded with 5-fluorouracil (5-FU) for potential use in cancer treatment.

MATERIALS AND METHODS

NanoHKUST-1 was prepared by reacting copper (II) acetate [Cu(OAc)₂] and benzene-1,3,5-tricarboxylic acid (H₃BTC) with benzoic acid (C₆H₅COOH) at room temperature (23.7°C±2.4°C). A central composite design was used to optimize 5-FU-loaded nanoHKUST-1. Contact time, ethanol concentration, and 5-FU:material ratios were the independent variables, and the entrapment efficiency of 5-FU was the response parameter measured. Powder X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen adsorption were used to determine the morphology of nanoHKUST-1. In addition, 5-FU release studies were conducted, and the in vitro cytotoxicity was evaluated.

RESULTS

Entrapment efficiency and drug loading were 9.96% and 40.22%, respectively, while the small-angle X-ray diffraction patterns confirmed a regular porous structure. The SEM and TEM images of the nanoHKUST-1 confirmed the presence of round particles (diameter: approximately 100 nm) and regular polygon arrays of mesoporous channels of approximately 2-5 nm. The half-maximal lethal concentration (LC₅₀) of the 5-FU-loaded nanoHKUST-1 was approximately 10 µg/mL.

CONCLUSION

The results indicated that nanoHKUST-1 is a potential vector worth developing as a cancer chemotherapeutic drug delivery system.

TS gene polymorphisms in gastric cancer and colorectal cancer

Gastric cancer and colorectal cancer are the most common gastrointestinal tumors worldwide. The development, metastasis and recurrence of gastric cancer and colorectal cancer are complex and are affected and regulated by many factors. These factors have important significance in guiding treatment and predicting prognosis. Recent studies have shown that thymidylic acid synthase (TS) is closely related with the occurrence, chemotherapy and prognosis of gastric cancer and colorectal cancer; however, there is still some controversy over this view. This review discusses the relationship between TS gene polymorphisms and gastric cancer and colorectal cancer.

Metal-organic frameworks as potential drug delivery systems

INTRODUCTION

Metal-organic frameworks (MOFs) are a unique class of hybrid porous solids based on metals and organic linkers. Compared to traditional porous materials, they possess predominance of large surface areas, tunable pore size and shape, adjustable composition and functionalized pore surface, which enable them unique advantages and promises for applications in adsorption and release of therapeutic agents.

AREAS COVERED

This review addresses MOFs as a new avenue for drug delivery and exhibits their ability to efficiently deliver various kinds of therapeutic agents. It also details the requirements that MOFs need to satisfy for biomedical application, such as toxicological compatibility, stability, particle size, and surface modification. In addition, several approaches used to enhance encapsulation efficiency are summarized and parameters influencing delivery efficiency are also discussed.

EXPERT OPINION

Benefiting from the unique advantages of MOFs materials, efficient delivery of various kinds of drugs has been achieved in some MOF materials. However, it is only the outset of MOFs in drug delivery system, and numerous work need to be done before clinical applications, for example, studying their in vivo toxicity, exploring degradation mechanisms so as to establish real stability of MOFs in body's liquid, providing appropriated surface modification avenue for MOFs, and researching in vivo efficiency and pharmacokinetics of drug-loaded MOFs.