Melatonin ameliorates 10-hydroxycamptothecin-induced oxidative stress and apoptosis via autophagy-regulated p62/Keap1/Nrf2 pathway in mouse testicular cells

10-Hydroxycamptothecin (HCPT) is a widely used clinical anticancer drug but has a significant side effect profile. Melatonin has a beneficial impact on the chemotherapy of different cancer cells and reproductive processes, but the effect and underlying molecular mechanism of melatonin's involvement in the HCPT-induced side effects in cells, especially in the testicular cells, are poorly understood. In this study, we found that melatonin therapy significantly restored HCPT-induced testicular cell damage and did not affect the antitumor effect of HCPT. Further analysis found that melatonin therapy suppressed HCPT-induced DNA damage associated with ataxia-telangiectasia mutated- and Rad3-related and CHK1 phosphorylation levels in the testis. Changes in apoptosis-associated protein levels (Bax, Bcl-2, p53, and Cleaved caspase-3) and in reactive oxygen species-associated proteins (Nrf2 and Keap1) and index (malondialdehyde and glutathione) suggested that melatonin treatment relieved HCPT-induced cell apoptosis and oxidative damage, respectively. Mechanistically, melatonin-activated autophagy proteins (ATG7, Beclin1, and LC3bII/I) may induce p62-dependent autophagy to degrade Keap1, eliciting Nrf2 from Keap1-Nrf2 interaction to promote antioxidant enzyme expression such as HO-1, which would salvage HCPT-induced ROS production and mitochondrial dysfunction. Collectively, this study reveals that melatonin therapy may protect testicular cells from HCPT-induced damage via the activation of autophagy, which alleviates oxidative stress, mitochondrial dysfunction, and cell apoptosis.

One-Pot Preparation of HCPT@IRMOF-3 Nanoparticles for pH-Responsive Anticancer Drug Delivery

Metal-organic frameworks (MOFs) are considered to be promising materials for drug delivery. In this work, a Zinc-based MOF nanocomposite IRMOF-3 was introduced as a drug carrier for 10-hydroxycamptothecine (HCPT). Without an extra drug-loading process, a nanoscale drug delivery material HCPT@IRMOF-3 was prepared via one-pot synthesis. The composition and structure of the material were investigated, and the drug release character was measured. Compared with preparing IRMOF-3 first and loading the drug, the one-pot-prepared HCPT@IRMOF-3 exhibited a higher drug-loading capacity. The material presented pH-responsive release. The HCPT release rate at pH 5.0 was significantly higher than that at pH 7.4. The cytotoxicity experiments showed that IRMOF-3 was non-toxic, and HCPT@IRMOF-3 exhibited notable cytotoxicity to Hela and SH-SY5Y cells. One-pot synthesis is a simple and rapid method for the preparation of an MOF drug delivery system, and IRMOF-3 can be potentially used in pH-responsive drug delivery systems.

Hydroxycamptothecin and Substratum Stiffness Synergistically Regulate Fibrosis of Human Corneal Fibroblasts

Corneal fibrosis is a common outcome of inappropriate repair associated with trauma or ocular infection. Altered biomechanical properties with increased corneal stiffness is a feature of fibrosis that cause corneal opacities, resulting in severe visual impairment and even blindness. The present study aims to determine the effect of hydroxycamptothecin (HCPT) and matrix stiffness on transforming growth factor-β1 (TGF-β1)-induced fibrotic processes in human corneal fibroblasts (HTK cells). HTK cells were cultured on substrates with different stiffnesses ("soft", ∼261 kPa; "stiff", ∼2.5 × 10³ kPa) and on tissue culture plastic (TCP, ∼10⁶ kPa) and simultaneously treated with or without 1 μg/mL HCPT and 10 ng/mL TGF-β1. We found that HCPT induced decreased cell viability and antiproliferative effects on HTK cells. TGF-β1-induced expression of fibrosis-related genes (FN1, ACTA2) was reduced if the cells were simultaneously treated with HCPT. Substrate stiffness did not affect the expression of fibrosis-related genes. The TGF-β1 induced expression of FN1 on both soft and stiff substrates was reduced if cells were simultaneously treated with HCPT. However, this trend was not seen for ACTA2, i.e., the TGF-β1 induced expression of ACTA2 was not reduced by simultaneous treatment of HCPT in either soft or stiff substrate. Instead, HCPT treatment in the presence of TGF-β1 resulted in increased gene expression of keratocyte phenotype makers (LUM, KERA, AQP1, CHTS6) on both substrate stiffnesses. In addition, the protein expression of keratocyte phenotype makers LUM and ALDH3 was increased in HTK cells simultaneously treated with TGF-β1 and HCPT on stiff substrate as compared to control, i.e., without HCPT. In conclusion, we found that HCPT can reduce TGF-β1-induced fibrosis and promote the keratocyte phenotype in a substrate stiffness dependent manner. Thus, HCPT stimulation might be an approach to stimulate keratocytes in the appropriate healing stage to avoid or reverse fibrosis and achieve more optimal corneal wound healing.

A novel GSH-triggered polymeric nanomicelles for reversing MDR and enhancing antitumor efficiency of hydroxycamptothecin

Tumor multidrug resistance (MDR) is one of the main reasons for the failure of clinical chemotherapy. Here, a bio-responsive anti-drug-resistant polymer micelle that can respond to the reductive GSH in the tumor microenvironment (TME) for delivery of HCPT was designed. A new type of polymer with anti-drug resistance and anti-tumor effect was synthesized and used to encapsulated HCPT to form reduction-sensitive micelles (PDSAH) by a thin-film dispersion method. It is demonstrated that the micelle formulation improves the anti-tumor activity and biosafety of HCPT, and also plays a significant role in reversing the drug resistance, which contributes to inhibiting the tumor growth and prolonging the survival time of H22 tumor-bearing mice. The results indicate that this nanoplatform can serve as a flexible and powerful system for delivery of other drugs that are tolerated by tumors or bacteria.

CDKL1 promotes the chemoresistance of human oral squamous cell carcinoma cells to hydroxycamptothecin

CDKL1 is a cyclin-dependent kinase-like kinase that is highly expressed in diverse types of cancer cells. However, the role of CDKL1 in the chemoresistance of oral squamous cell carcinoma (OSCC) remains largely undefined. Here, we explored the role of CDKL1 in the chemoresistance of the human OSCC cell line CAL27 to hydroxycamptothecin (HCPT). Real-time quantitative polymerase chain reaction and western blotting revealed that exposure of CAL27 cells to HCPT led to a marked increase in the expression of CDKL1 at the mRNA and protein levels. Knockdown of CDKL1 significantly suppressed cell proliferation and induced cell cycle G0/G1 phase arrest in CAL27 cells based on the results of MTT and flow cytometry assays, respectively. CAL27 cells displayed attenuated biological activity of the cell population. After treatment with HCPT, whereas CDKL1 overexpression increased the resistance to HCPT of the remaining cells. Moreover, the western blot showed that the expression of cleaved-caspase 3 and phosphorylated ataxia telangiectasia mutated proteins was upregulated by HCPT treatment in CAL27 cells. Furthermore, CDKL1 overexpression partially reversed the inhibitory effects of HCPT in CAL27 cells. These results suggest that CDKL1 overexpression decreased the chemosensitivity of OSCC cells to HCPT, indicating a potential strategic approach for reversing the HCPT resistance in human OSCC.

Redox-responsive supramolecular hydrogel based on 10-hydroxy camptothecin-peptide covalent conjugates with high loading capacity for drug delivery

A redox-responsive supramolecular hydrogel system was developed for delivering 10-hydroxy camptothecin (HCPT). The hydrogel was formed by cleaving disulfide bond. The combination of hydrophobic HCPT with hydrogel was a simple and effective way to improve the solubility of HCPT and the drug loading capacity of delivery system. The transmission electron microscopy (TEM) image revealed the self-assembled hydrogel was long and thin nanofibers with a width of <10nm. Rheological test verified the hydrogel had fine physical properties. In vitro release experiment showed that the accumulative releasing percentages within 72h of HCPT-peptide hydrogels at 3.0%, 4.0%, 5.0% were 16.8%, 21.3%, and 26.8% respectively, which indicated the HCPT-peptide hydrogels had a significantly sustained-release characteristic. Besides, in vitro anticancer assay showed that HCPT-peptide hydrogels possessed a favorable anticancer efficacy. These results indicated that HCPT-peptide hydrogel had great potential for cancer treatment as a novel injectable drug delivery system.

Preparation of HCPT-Loaded Nanoneedles with Pointed Ends for Highly Efficient Cancer Chemotherapy

The high-aspect-ratio nanoparticles were proved to be internalized much more rapidly and efficiently by cancer cells than the nanoparticles with an equal aspect ratio. Herein, a kind of high-aspect ratio, pointed-end nanoneedles (NDs) with a high drug loading (15.04 %) and the prolonged drug release profile were fabricated with an anti-tumor drug-10-hydroxycamptothecin (HCPT)-via an ultrasound-assisted emulsion crystallization technique. It is surprising to see that the cellular internalization of NDs with an average length of 5 μm and an aspect ratio of about 12:1 was even much faster and higher than that of nanorods with the same size and the nanospheres with a much smaller size of 150 nm. The results further validated that cellular internalization of the nanoparticles exhibited a strong shape-dependent effect, and cellular uptake may favor the particles with sharp ends as well as a high-aspect ratio instead of particle size. The NDs with enhanced cytotoxicity would lead to a promising sustained local drug delivery system for highly efficient anticancer therapy. More importantly, the fabrication of NDs opens a door to design new formulations of nanoneedle drug delivery systems for highly efficient cancer.

Effects of 10-hydroxycamptothecin on intrinsic mitochondrial pathway in silkworm BmN-SWU1 cells

10-Hydroxycamptothecin (HCPT), a plant alkaloid isolated from Camptotheca acuminate, is known as a planted-derived insecticide, however, the specific mechanism in insect cells is still unclear. In this study, we treated the ovarian cell line of the silkworm, BmN-SWU1, with different HCPT doses for durations ranging from 0 to 72h. The apoptosis morphology was evident after 72h of incubation and included cell protuberance, concentrated cytoplasm and apoptotic bodies. We observed DNA fragmentation and cell apoptosis after HCPT treatment. The disruption of mitochondrial distribution, activation of the intracellular mitochondrial permeability transition pore, and release of cytochrome c during HCPT-induced apoptosis in dose and time-dependent manner indicate the involvement of mitochondria in BmN-SWU1 cells. Caspase-9 and -3 activities increased gradually with the duration of incubation time. In conclusion, HCPT has a significant effect to initiate the intrinsic mitochondrial pathway in silkworm cells, providing a theoretical basis for better application of plant-derived insecticide in pest control.

Hydroxycamptothecin-induced apoptotic gene expression profiling by PCR array in human Tenon's capsule fibroblasts

Studies have indicated that hydroxycamptothecin (HCPT) induces apoptosis of fibroblasts. In this study, we investigated the apoptotic gene expression profiling in HCPT-treated -human Tenon's capsule fibroblasts (HTCFs) and identify the most implicated gene in apoptotic signaling of HTCFs by HCPT. Method HTCFs were incubated with HCPT at 0, 0.25 and 4 mg/L for 24, 48 and 72 h, respectively. Anti-proliferative effects were measured by MTT assay. Apoptosis was determined using the Annexin V-FITC/PI apoptosis detection kit and apoptotic cells were identified by flow cytometry. A PCR array was employed to analyze the most implicated apoptotic genes during HCPT-induced apoptosis in HTCFs. Results from our studies showed that HCPT induced apoptosis in HTCFs in a concentration-and time-dependent manner. The apoptotic HTCFs was increased by 9.38% with a multiplicity at 4 mg/L HCPT. PCR array demonstrated remarkable changes in 88 apoptotic genes, including 9 up-regulated genes and 36 down-regulated genes. HCPT treatment induced the upregulation of CHOP and downregulation of XIAP in HTCFs. To conclude, our results support HCPT induced the apoptosis of HTCFs, involving the activation of mitochondrial and endoplasmic reticulum stresses as well as the downregulation expression of XIAP.

Carbon nanotubes for delivery of small molecule drugs

In the realm of drug delivery, carbon nanotubes (CNTs) have gained tremendous attention as promising nanocarriers, owing to their distinct characteristics, such as high surface area, enhanced cellular uptake and the possibility to be easily conjugated with many therapeutics, including both small molecules and biologics, displaying superior efficacy, enhanced specificity and diminished side effects. While most CNT-based drug delivery system (DDS) had been engineered to combat cancers, there are also emerging reports that employ CNTs as either the main carrier or adjunct material for the delivery of various non-anticancer drugs. In this review, the delivery of small molecule drugs is expounded, with special attention paid to the current progress of in vitro and in vivo research involving CNT-based DDSs, before finally concluding with some consideration on inevitable complications that hamper successful disease intervention with CNTs.

Synthesis and anticancer activities of 5,6,7-trimethoxy-N-phenyl(ethyl)-4-aminoquinazoline derivatives

A series of 5,6,7-trimethoxy-N-phenyl(ethyl)-4-aminoquinazoline compounds was prepared by microwave irradiation and conventional heating methods. Compounds 6p, 6q, and 6x strongly inhibited extracellular regulated kinase1/2 (ERK1/2) phosphorylation induced by epidermal growth factor (EGF) at 1.28 μM in PC3 cells. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed that all compounds had certain anticancer activities, and the IC₅₀ values of 6x were 6.2 ± 0.9, 3.2 ± 0.1, and 3.1 ± 0.1 μM against PC3, BGC823, and Bcap37 cells, respectively. Acridine orange/ethidium bromide staining, Hoechst 33258 staining, DNA ladder, and flow cytometry analyses revealed that 6x induced cell apoptosis in PC3 cells, with apoptosis ratios of 11.6% at 1 μM and 31.8% at 10 μM after 72 h.

Preparation of 10-hydroxycamptothecin-loaded glycyrrhizic acid-conjugated bovine serum albumin nanoparticles for hepatocellular carcinoma-targeted drug delivery

INTRODUCTION

The livertaxis of glycyrrhizic acid-conjugated bovine serum albumin (GL-BSA) has been reported in the literature. Now, in this paper, we describe a novel type of drug-targeted delivery system containing 10-hydroxycamptothecin (HCPT) with liver tumor targeting.

METHODS

First, GL was coupled to BSA then HCPT was encapsulated in GL-BSA by high-pressure homogenization emulsification. In the experimental design, the influencing variables on particle size and drug loading efficiency were determined to be BSA concentration, volume ratio of water to organic phase, and speed and speed duration of homogenization as well as homogenization pressure and the number of times homogenized at certain pressures. Particle size plays an important role in screening optimal conditions of nanoparticles preparation. Characteristics of 10-hydroxycamptothecin-loaded glycyrrhizic acid-conjugated bovine serum albumin nanoparticles (GL-BSA-HCPT-NPs), such as the drug encapsulation efficiency, drug loading efficiency, and GL-BSA content were studied. In addition, the morphology of the nanoparticles (NPs) and weight loss rate were determined and Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, and thermal analysis performed.

RESULTS

The average particle size of the sample NPs prepared under optimal conditions was 157.5 nm and the zeta potential was -22.51 ± 0.78 mV; the drug encapsulation efficiency and drug loading efficiency were 93.7% and 10.9%, respectively. The amount of GL coupling to BSA was 98.26 μg/mg. Through physical property study of the samples, we determined that the HCPT had been successfully wrapped in GL-BSA. In vitro drug-release study showed that the nanoparticles could release the drug slowly and continuously. Hemolysis testing showed the safety of GL-BSA as a novel drug delivery system. The targeting properties of GL-BSA-HCPT-NPs were studied in an in vitro cell uptake study and cell proliferation assay. Cells incubated with GL-BSA-HCPT-NPs and labeled with fluorescein isothiocyanate showed more extensive fluorescence spots and stronger fluorescence intensity than samples without GL conjugation. MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used to determine the inhibitory rate of the samples. It was found that the inhibitory rate of GL-BSA-HCPT-NPs develops as concentration rises. Further, the inhibitory rate of GL-BSA-HCPT-NPs was higher at the same concentration and had a lower half maximal inhibitory concentration value than the other samples. The half maximal inhibitory concentration values of GL-BSA-HCPT-NPs, BSA-HCPT-NPs, and HCPT sodium were 0.78 ± 0.015, 1.62 ± 0.039, and 7.93 ± 0.255 μg/mL, respectively.

CONCLUSION

The results of this study show GL-BSA-HCPT to be a promising new vehicle for hepatocellular carcinoma-targeting therapy.