Integrin αvß3-Specific Hydrocyanine for Cooperative Targeting of Glioblastoma with High Sensitivity and Specificity.

Glioblastoma is a highly malignant brain tumor with poor prognosis and survival rate because of a lack of effective diagnostic methods. Hydrocyanines are a type of reactive oxygen species (ROS)-responsive fluorescent probes, allowing for distinguishing tumor cells from normal cells based on their different intracellular levels of ROS. However, their diagnostic applications for glioblastoma have been limited because of the inability to discriminate between tumor cells and other tissues with high ROS production, leading to high false-positive diagnosis. Therefore, tumor-responsive and -specific hydrocyanines with cooperative targeting ability have great potential for improving the diagnosis and treatment of glioblastoma. Integrin αvß3 plays a critical role in the progression and angiogenesis of glioblastoma and has become a promising target for diagnosing glioblastoma. Herein, we identify a specific peptide ligand for integrin αvß3, Arg-Trp-(d-Arg)-Asn-Arg (RWrNR), which shows high binding affinity to human glioblastoma U87MG cells. Importantly, hydro-Cy5-RWrNR conjugation allowed for distinguishing U87MG cells from normal cells in response to intracellular ROS. Particularly, hydro-Cy5-RWrNR could not only selectively accumulate in orthotopic U87MG tumor with minimal background fluorescence but also effectively discriminate between glioblastoma and inflammatory tissues for the first time, leading to detection of glioblastoma in vivo with high target-to-background ratios and minimal background fluorescence. Therefore, hydro-Cy5-RWrNR is the first integrin αvß3-specific hydrocyanine probe and has great potential in precise tumor diagnosis because of its cooperative targeting of integrin αvß3 and ROS.

Synergistic Amplification of Oxidative Stress-Mediated Antitumor Activity via Liposomal Dichloroacetic Acid and MOF-Fe2.

Cancer cells are susceptible to oxidative stress; therefore, selective elevation of intracellular reactive oxygen species (ROS) is considered as an effective antitumor treatment. Here, a liposomal formulation of dichloroacetic acid (DCA) and metal-organic framework (MOF)-Fe2+ (MD@Lip) has been developed, which can efficiently stimulate ROS-mediated cancer cell apoptosis in vitro and in vivo. MD@Lip can not only improve aqueous solubility of octahedral MOF-Fe2+ , but also generate an acidic microenvironment to activate a MOF-Fe2+ -based Fenton reaction. Importantly, MD@Lip promotes DCA-mediated mitochondrial aerobic oxidation to increase intracellular hydrogen peroxide (H2 O2 ), which can be consequently converted to highly cytotoxic hydroxyl radicals (•OH) via MOF-Fe2+ , leading to amplification of cancer cell apoptosis. Particularly, MD@Lip can selectively accumulate in tumors, and efficiently inhibit tumor growth with minimal systemic adverse effects. Therefore, liposome-based combination therapy of DCA and MOF-Fe2+ provides a promising oxidative stress-associated antitumor strategy for the management of malignant tumors.

A sensitive and fast responsive fluorescent probe for imaging hypoxic tumors.

Nitroreductase activities are positively associated with the hypoxic level of tumors, making it an attractive target for tumor detection. Herein, we have developed a 2,5-bis(methylsulfinyl)-1,4-diaminobenzene based probe (BBP), which is a nitroreductase (NTR) responsive fluorescent probe and can rapidly detect NTRs with high sensitivity and specificity. The BBP showed not only a selective response to NTRs over other biological reductants, but also high sensitivity to NTRs and could detect as low as 20 ng mL-1 NTRs. Furthermore, the BBP responded rapidly to NTRs in as fast as 10 minutes, enabling real-time monitoring of the production levels of NTRs. Most importantly, the BBP could identify NTR activities in 2D cell monolayers, 3D tumor spheroids, and even solid tumors in mice. Particularly, the BBP could monitor the early tumor formation and treatment response via measuring NTR activities. Overall, the BBP appears to be an ideal imaging probe for the detection of solid tumors, and possesses great potential in a broad range of diagnostic and therapeutic applications in the clinic.

Discovery and characterization of a novel peptide inhibitor against influenza neuraminidase.

Neuraminidase, an abundant glycoprotein on the influenza virus surface, plays crucial roles in virus replication. Targeting neuraminidase could be a splendid way for the prevention of the spread of influenza infections. Herein, we have identified an octapeptide (errKPAQP) from a synthesized peptide library, originating from mimicking the binding pocket of oseltamivir in neuraminidase, as a potent peptide neuraminidase inhibitor. The docking-based virtual studies showed that errKPAQP exhibited a strong binding affinity (a docking score of -20.03) and nanomolar affinity (11 nM) to influenza neuraminidase, and can inhibit neuraminidase activity at a concentration as low as 4.25 µM, leading to effective protection of MDCK cells from influenza virus-induced death and replication. Furthermore, errKPAQP presented low hemolytic activity, minimal cytotoxicity, and good pharmacokinetic characteristics, which are imperative for an anti-influenza drug. Importantly, errKPAQP was capable of reducing influenza virus-induced inflammation, the serious damage to the lung tissues, and mortality rates in infected mice, indicating that it could protect against the lethal challenge of influenza viruses in vivo. Therefore, we have developed a novel neuraminidase peptide inhibitor with advantageous biological properties and high inhibitory activity towards neuraminidase, and it can serve as a promising anti-influenza drug.

Ultrasound-responsive alkaline nanorobots for the treatment of lactic acidosis-mediated doxorubicin resistance.

Lactic acidosis is one of the key characteristics of the tumor microenvironment (TME), and plays a critical role in therapy resistance, making it an attractive target for enhancing anticancer treatment. However, no effective systems exhibit the ability to selectively neutralize tumor lactic acidosis in a controlled manner. Here, we have developed novel ultrasound-responsive alkaline nanorobots (AN-DSP), composed of PLGA nanoparticles containing doxorubicin (DOX), sodium carbonate (Na2CO3) and perfluorocarbon (PFC), for recovering from lactic acidosis-mediated drug resistance. AN-DSP exhibit sensitive response to ultrasound stimulation, and rapidly release Na2CO3 to neutralize lactic acidosis, consequently enhancing DOX susceptibility in vitro and in vivo. Particularly, our nanorobots autonomously accumulate in tumors by an enhanced permeability and retention effect, and can specifically disrupt the tumor acidic microenvironment in response to external ultrasonic powering, resulting in the inhibition of tumor growth with minimal adverse effects. Therefore, AN-DSP represent a promising approach for selectively overcoming tumor lactic acidosis induced therapeutic resistance.

Bioactive multi-engineered hydrogel offers simultaneous promise against antibiotic resistance and wound damage.

Wound healing is a complex process involved in repairing tissue damage and preventing infection. However, there is a lack of appropriate treatment solutions that can simultaneously promote tissue repair and protect againstbacteria, especially antibiotic-resistant bacteria. In this study, we have developed an injectable hydrogel encapsulating acidic fibroblast growth factor (aFGF) and bacteriophage, termed as ABgel, for combating antibiotic-resistant bacteria and enhancing wound regeneration. ABgel is composed of oxidized sodium alginate (OSA), gelatin and hyaluronic acid (HA), and can rapidly form hydrogel with an elastic modulus of 13 kPa, which mimics the skin tissues. In addition, ABgel can effectively load and stabilize bacteriophage and aFGF, allowing for preventing bacterial infections and improving regeneration of damaged dermal tissues. In vitro studies demonstrate that ABgel exhibits enormous antibacterial activity against antibiotic-resistant E. coli and enhanced angiogenetic activity. Importantly, ABgel can promote skin regeneration and prevent bacterial infections in mice, thereby promoting wound healing process. Therefore, ABgel represents a decent bioactive engineered hydrogel dressing with a broad application potential.

A stimuli-responsive combination therapy for recovering p53-inactivation associated drug resistance.

Drug resistance is a major hindrance in the anticancer treatment, which encourages the development of effective therapeutic strategies. For the first time, MDM2-mediated p53 degradation was identified as a critical factor for developing acquired resistance of doxorubicin (DOX) in HepG2 tumor spheroids, which could be effectively reversed by MDM2 inhibitor MI-773, thereby improving anticancer effects. Therefore, a pH-sensitive liposomal formulation of DOX and MI-773 (LipD/M@CMCS) were developed for recovering p53-mediated DOX resistance in hepatocellular carcinoma. LipD/M@CMCS were composed of cationic liposomes covered with carboxymethyl chitosan (pI = 6.8), and were stable in the physiological condition (pH 7.4), but rapidly converted to cationic liposomes in tumor acidic microenvironment (pH 6.5), endowing them with tumor specificity and enhanced cellular uptake. We showed that LipD/M@CMCS could not only effectively induce cell apoptosis in HepG2 tumor spheroids, but significantly inhibit tumor growth with minimal adverse effects. In summary, selective regulation of MDM2 in cancer cells is a promising strategy to overcome DOX resistance, and may provide a perspective on the management of malignant tumors.

The first integrins ß3-mediated cellular and nuclear targeting therapeutics for prostate cancer.

Prostate cancer is one of the most commonly diagnosed cancers in men, leading to a high mortality rate due to a lack of effective anticancer treatment. Current anticancer chemotherapeutics are often administrated at suboptimal doses because of nonspecific toxicities to normal tissues, resulting in the eventual failure of therapy as well as the development of drug resistance and metastatic disease. Therefore, ligand-targeted therapeutics have the great potential of improving the selective anticancer toxicity. Integrins ß3 (αvß3 and αIIbß3) are an important cell adhesion molecular family, overexpressed on both cell membrane and perinuclear region of prostate cancer cells, and play a key role in the progression and metastasis of prostate cancer, making them an attractive target for anticancer therapy. However, their clinical impacts have been limited due to lack of specific ligands. Here, for the first time, we have identified a peptide Arginine-Tryptophan-(D-Arginine)-Asparagine-Arginine as an integrins ß3 specific ligand, named B3int, which shows superior selectivity to integrins ß3 over other integrin subunits. B3int has high affinity to integrins ß3 with a Kd value of 0.2 nM, which is 7-fold higher than c-RGDyK (1.4 nM), a well-established integrin αvß3 ligand. In addition, B3int shows high specificity for integrins ß3, and can selectively target integrin ß3 overexpressed cancer cells in vitro and in vivo. Most importantly, B3int-modified liposomes (B3int-LS-DOX) can selectively deliver DOX not only into prostate cancer cells, but into nucleus via targeting integrins ß3, thereby significantly improving anticancer effects in 2D prostate cancer cells and 3D tumor spheroids. Particularly, B3int-LS-DOX effectively inhibits tumor growth with an effective dose of as low as 1.5 mg/kg, which is 3.3-fold less than c-RGDyK-LS-DOX (5 mg/kg), indicating that integrins ß3 specific therapy is a promising anticancer strategy which can greatly improve the anticancer therapeutic index. In summary, we have identified B3int as the first integrins ß3 specific ligand with high affinity and specificity, and holds a great potential of improving the diagnosis and treatment for integrins ß3-overexpressed cancers.

An elegant nitroreductase responsive fluorescent probe for selective detection of pathogenic Listeria in vitro and in vivo.

Listeria monocytogenes (Listeria) is a facultative pathogenic bacterium, and a sensitive method for specific detection of Listeria is considered of clinically significant. However, current approaches for identifying Listeria are time consuming or tentative, and especially, cannot identify bacterial viability and antibiotic efficacy, which are critical in establishing a treatment recipe. Herein, we have developed a nitroreductase (NTR) responsive fluorescent probe (NRFP) with a fluorescence off-on feature, which could rapidly detect Listeria in vitro and in vivo with high specificity and sensitivity. NRFP showed a selective response to NTRs over other biological reductants, and could detect NTRs as low as 12.5 ng/mL. Furthermore, NRFP responded rapidly to NTRs within 10 min, enabling it real-time monitoring NTR production. Most importantly, NRFP could not only distinguish Listeria from other bacteria in vitro and in vivo for the first time, but could provide valuable information about Listeria desired for healthcare professionals, such as the presence and viability. Particularly, NRFP could real-time monitor antimicrobial effects in vivo, thereby identifying effective antibiotics for Listeria infections. Overall, NRFP appears to be an ideal imaging probe for Listeria, and possesses great potentials in diagnostic and therapeutic applications.

A potent free fatty acid receptor 1 agonist with a glucose-dependent antihyperglycemic effect.

We present a novel free fatty acid receptor 1 (FFA1) agonist, named PAFA, with a strong agonist potency (EC50 = 6.04 nM) and good serum stability. PAFA significantly stimulates insulin secretion in INS-1 cells in a glucose-dependent manner and exhibits high antihyperglycemic effects in db/db mice without adverse effects.

Novel Gold Nanorod-Based HR1 Peptide Inhibitor for Middle East Respiratory Syndrome Coronavirus.

Middle East respiratory syndrome coronavirus (MERS-CoV) causes a severe acute respiratory syndrome-like illness with high pathogenicity and mortality due to the lack of effective therapeutics. Currently, only few antiviral agents are available for the treatment of MERS, but their effects have been greatly impaired by low antiviral activity, poor metabolic stability, and serious adverse effects. Therefore, the development of effective treatment for MERS is urgently needed. In this study, a series of heptad repeat 1 (HR1) peptide inhibitors have been developed to inhibit HR1/HR2-mediated membrane fusion between MERS-CoV and host cells, which is the major pathway of MERS-CoV-induced host infections. Particularly, peptide pregnancy-induced hypertension (PIH) exhibits potent inhibitory activity with IC50 of 1.171 µM, and its inhibitory effects can be further increased to 10-fold by forming a gold nanorod complex (PIH-AuNRs). In addition, PIH-AuNRs display enhanced metabolic stability and biocompatibility in vitro and in vivo and, therefore, effectively prevent MERS-CoV-associated membrane fusion. In summary, PIH-AuNRs represent a novel class of antiviral agents and have a great potential in treating MERS in the clinic.