Engineering of an endogenous hydrogen sulfide responsive smart agent for photoacoustic imaging-guided combination of photothermal therapy and chemotherapy for colon cancer.

INTRODUCTION: Photothermal therapy can be synergistically combined with chemotherapy to improve the therapeutic effect for colon cancer. However, conventional therapeutic agents have side effects in normal tissues, limiting their application. OBJECTIVES: To reduce these side effects, a smart agent (Cur@HKUST-1@PVP) whose functionality is triggered by the high content of endogenous hydrogen sulfide in colon tumors was engineered for photoacoustic imaging-guided combination of photothermal therapy and chemotherapy for colon tumors. METHODS: After reacting with hydrogen sulfide, Cur@HKUST-1@PVP simultaneously generates CuS and releases curcumin. The generated CuS serves as an imaging agent for both photothermal therapy and photoacoustic imaging, while the released curcumin is used for chemotherapy. RESULTS: In vivo photoacoustic imaging experiments demonstrated that Cur@HKUST-1@PVP can be used for selectively imaging colon cancer tumors. In vivo experiments in mice for treatment suggested that the endogenous hydrogen sulfide-activated combination of photothermal therapy and chemotherapy has a better treatment effect that photothermal therapy or chemotherapy treatment alone. CONCLUSION: The endogenous hydrogen sulfide-activated Cur@HKUST-1@PVP agent developed herein shows great potential for the accurate diagnosis and effective treatment of colon cancer.

Hyaluronic acid-coated Bi:Cu2O: an H2S-responsive agent for colon cancer with targeted delivery and enhanced photothermal performance.

BACKGROUND: Endogenous hydrogen sulfide (H2S)-responsive theranostic agents have attracted extensive attention due to their specificity for colon cancer. However, the development of such agents with high enrichment in tumors and excellent photothermal performance remains challenging. RESULTS: We prepared hyaluronic acid (HA)-coated Bi-doped cuprous oxide (Bi:Cu2O@HA) via a one-pot method. The HA specifically targets colon cancer tumor cells to improve the enrichment of Bi:Cu2O@HA at tumor sites, while the doped Bi both enhances the photothermal performance of the H2S-triggered Cu2O and serves as an agent for tumor imaging. The results in this work demonstrated that the Bi:Cu2O@HA nanoparticles exhibit good biocompatibility, target colon cancer tumor cells, facilitate computed tomography imaging, and enhanced H2S-responsive photothermal therapy performance, resulting in an excellent therapeutic effect in colon cancer. CONCLUSIONS: The novel Bi:Cu2O@HA nanoparticles exhibit excellent tumor targeting and photothermal therapeutic effects, which provide new strategies and insights for colon cancer therapy.

A novel dendritic mesoporous silica based sustained hydrogen sulfide donor for the alleviation of adjuvant-induced inflammation in rats.

PURPOSE: S-propargyl-cysteine (SPRC), an excellent endogenous hydrogen sulfide (H2S) donor, could elevate H2S levels via the cystathionine γ-lyase (CSE)/H2S pathway both in vitro and in vivo. However, the immediate release of H2S in vivo and daily administration of SPRC potentially limited its clinical use. METHODS: To solve the fore-mentioned problem, in this study, the dendritic mesoporous silica nanoparticles (DMSN) was firstly prepared, and a sustained H2S delivery system consisted of SPRC and DMSN (SPRC@DMSN) was then constructed. Their release profiles, both in vitro and in vivo, were investigated, and their therapeutical effect toward adjuvant-induced arthritis (AIA) rats was also studied. RESULTS: The spherical morphology of DMSN could be observed under scanning Electron Microscope (SEM), and the transmission electron microscope (TEM) images showed a central-radiational pore channel structure of DMSN. DMSN showed excellent SPRC loading capacity and attaining a sustained releasing ability than SPRC both in vitro and in vivo, and the prolonged SPRC releasing could further promote the release of H2S in a sustained manner through CSE/H2S pathway both in vitro and in vivo. Importantly, the SPRC@DMSN showed promising anti-inflammation effect against AIA in rats was also observed. CONCLUSIONS: A sustained H2S releasing donor consisting of SPRC and DMSN was constructed in this study, and this sustained H2S releasing donor might be of good use for the treatment of AIA.

Endogenous Hydrogen Sulfide Promotes Apoptosis via Mitochondrial Pathways in the Livers of Broilers with Selenium Deficiency Exudative Diathesis Disease.

Hydrogen sulfide (H2S), an endogenous gasotransmitter, plays an important role in apoptosis. Exudative diathesis (ED) disease is associated with dietary selenium (Se) deficiency in broilers. The liver is one of the target organs of Se deficiency; however, little is known about the effect of H2S on apoptosis via mitochondrial pathways in the livers of broilers with ED disease. In the present study, we aimed to investigate the correlation between endogenous H2S and mitochondrial-mediated apoptosis in the livers of broilers with ED disease, as induced by Se deficiency. One hundred twenty healthy, 1-day-old broilers were randomly assigned to one of two groups (60 each) based on diet: Basal diet (control group, 0.2 mg/kg Se) or a low-Se diet (-Se group, 0.033 mg/kg Se). At day 20, 15 broilers of a similar weight were sacrificed from the control group, while the same number of broilers were euthanatized from the -Se group when displaying typical symptoms of ED between days 18 and 25. The livers were collected, and apoptosis was measured using a TUNEL assay. Additionally, H2S concentration, the expression of H2S synthases of cystathionine γ-lyase (CSE), cystathionine ß-synthase (CBS), and 3-mercaptopyruvate sulfurtransferase (3-MST), as well as mitochondrial apoptosis-related genes of Bcl-2, Bax, Bak, Cyt-C, Caspase-9, Caspase-3, and p53, were examined in livers. The results indicated that Se deficiency could induce apoptosis in the livers of broilers. Swelling, fractures, and vacuolization were visible in the mitochondrial cristae in the livers of the -Se group. The expression of H2S synthase-related genes and H2S concentration was significantly enhanced (P < 0.05) in the livers of the -Se group compared to controls. Moreover, a low-Se diet downregulated (P < 0.05) the level of Bcl-2 and upregulated (P < 0.05) the levels of Bax, Bak, Cyt-C, Caspase-9, Caspase-3, and p53. These results suggest that an H2S increase in the livers of ED broilers, which was induced by Se deficiency, is related to apoptosis mediated by mitochondrial pathways.