Latest ArticlesA nine cyclic peptide (TCP-1) showed excellent specificity for colon cancer. TCP-1 binds with human tumor tissues at early stages and mice tumor with diameters of 1-4 mm, suggesting that TCP-1 may be used for early diagnosis of colon cancer. The mechanism of the targeted binding of TCP-1 to colon cancer was also studied using immunoprecipitation, LC-MS and bioinformatics. After screening and identifying of the possible binding target proteins of TCP-1, keratin, type Ⅱ cytoskeletal 5 was speculated to be the specific binding target protein of TCP-1 in human tumor tissue. Pharmacokinetics studies were conducted to investigate the target-mediated drug disposition of the new tumor-specific peptide by LC-MS/MS. The tissue distribution study showed that TCP-1 was found only in colon tumors (the target site) in tumor mice did not bind to any other tissues. Conjugating TCP-1 to tumor markedly increased its removal rate from blood circulation but mildly extended its staying time in vivo. In tumor mice, a lower AUC of TCP-1 (reduced by almost 35%) and 2-fold higher clearance were found compared to that of normal mice. The proposed metabolic pathway of TCP-1 in the kidney was also determined using LC-MSn-IT-TOF. The high specificity and low toxicity of the peptide may be caused by its extremely tight binding to the targets. Potential applications for future clinical use, including MRI and PET/CT were also explored, and this research may promote the development of colon cancer diagnostic technology research and provide new ideas and technical routes for tumor diagnostic technology.
Thermocatalytic nonoxidative ethane dehydrogenation (EDH) is a promising strategy for ethene production but suffers from intense energy consumption and poor catalyst durability; exploring technology that permits efficient EDH by solar energy remains a giant challenge. Herein, we present that an oxygen vacancy (Ov)-rich LaVO4 (LaVO4-Ov) catalyst is highly active and stable for photocatalytic EDH, through a dynamic lattice oxygen (Olatt.) and Ov co-mediated mechanism. Irradiated by simulated sunlight at mild conditions, LaVO4-Ov effectively dehydrogenates undiluted ethane to produce C2H4 and CO with a conversion of 2.3%. By loading a small amount of Pt cocatalyst, the evolution and selectivity of C2H4 are enhanced to 275 µmol h−1 g−1 and 96.8%. Of note, LaVO4-Ov appears nearly no carbon deposition after the reaction. The isotope tracked reactions reveal that the consumed Olatt. recuperates by exposing the used catalyst with O2, thus establishing a dynamic cycle of Olatt. and achieving a facile catalyst regeneration to preserve its intrinsic activity. The refreshed LaVO4-Ov exhibits superior reusability and delivers a turnover number of about 305. The Ov promotes photo absorption, boosts ethane adsorption/activation, and accelerates charge separation/transfer, thus improving the photocatalytic efficiency. The possible photocatalytic EDH mechanism is proposed, considering the key intermediates predicted by density functional theory (DFT) and monitored by in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS).
Here, we report a concise and divergent enantioselective total synthesis of marine sesquiterpene quinone meroterpenoids (+)-dysidavarones A–C (1–3) using predysidavarone 6 as a key common intermediate. The highly strained and bridged eight-membered carbocycle of predysidavarone 6 was constructed by a one-pot intermolecular alkylation and intramolecular arylation of Wieland–Miescher ketone derivative 11 and benzyl bromide 12. The total synthesis of (+)-dysidavarones A–C (1–3) was achieved from predysidavarone 6 in a divergent manner by a late-stage introduction of the ethoxy group, which reveals the possible source of the ethoxy group within (+)-dysidavarones A–C (1–3) and provides a late-stage modifiable route for the synthesis of dysidavarone analogs for further anti-cancer activity evaluation.
Catalytic Michael addition reaction represents a fundamental importance in organic synthetic chemistry. Whereas corresponding conversions toward intrinsically low reactive enamide remains an ongoing challenging. We herein report a copper-catalyzed conjugate addition of allenes to β-substituted alkenyl amides, one of the most challenging Michael acceptors. The present method utilizes readily available allenes as the latent carbon-based nucleophiles and simple, common β-substituted alkenyl amides as starting materials, unlike previous methods that usually preinstall an activating group to improve the reactivity of amide or uses highly reactive stoichiometric quantities of organometallics. Hence, this approach shows good functional group compatibility and can be implemented under mild reaction conditions with excellent level of chemo- and regioselectivities.
Understanding the dynamic assembly process of DNA nanostructures is important for developing novel strategy to design and construct functional devices. In this work, temperature-controlled dynamic light scattering (DLS) strategy has been applied to study the global assembly process of DNA origami and DNA bricks. Through the temperature dependent size and intensity profiles, the self-assembly process of various DNA nanostructures with different morphologies have been well-studied and the temperature transition ranges could be observed. Taking advantage of the DLS information, rapid preparation of the DNA origami and the brick assembly has been realized through a constant temperature annealing. Our results demonstrate that the DLS-based strategy provides a convenient and robust tool to study the dynamic process of forming hieratical DNA structures, which will benefit understanding the mechanism of self-assembly of DNA nanostructures.
Human Notum (hNotum) inhibitors could be used for treating Wnt signalling-associated diseases including colorectal cancer. Herein, two series of chalcone derivatives were designed and synthesized aiming to find selective and potent hNotum inhibitors. Structure–activity relationship (SAR) studies showed that 2-methoxyl and 5-bromine substitutions on A-ring significantly enhanced anti-hNotum effect, while 4′-ethoxyl and 3′-alkyl substitutions on B-ring were beneficial for hNotum inhibition. Among all tested chalcones, B11 displayed the most potent anti-Notum effect (IC50 = 3.6 nmol/L), good selectivity, excellent chemical stability and suitable metabolic stability. Further investigations showed that B11 acted as a competitive inhibitor of hNotum, while this agent (5 µmol/L) significantly weaken the migration abilities of colorectal cancer cells. Collectively, this study deciphers the SARs of chalcones as hNotum inhibitors and reports a novel and potent hNotum inhibitor with the anti-migration effect on colorectal cancer cells, which offers a promising lead compound to develop novel anti-cancer agents.
Owing to the anaerobic metabolism in the tumor, abundant acidic metabolites are produced and accumulated in the cells. Therefore, the cells in different tumor layers are directly linked to the pH micro-environment. Nevertheless, due to the lack of robust tools, the high-efficient evaluation of the acidic micro-environment of tumor stratification faces the challenge of accurate diagnosis. We designed a new pH sensitive fluorescent lifetime probe target to lysosomes. As we expected, the fluorescence lifetime of PLN possesses a good linear fit to the pH value, which could detect the pH change at a single lysosome level in real time, and then evaluate the different acidity of tumor stratification. The probe PLN is successfully used to evaluate the tumor stratification by fluorescence lifetime imaging microscopy (FLIM) for the first time, which is of great significance in the preoperative diagnosis of clinical tumor treatment or evaluation of drug delivery effect.
Oral squamous cell carcinoma (OSCC) is known as one of the most malignant tumors with high recurrence and fatality rate. The poor tumor-targeting ability of traditional chemotherapeutic drugs has been a grand challenge for anti-OSCC therapy. Beyond that, a large quantity of tumor associated macrophages in OSCC tissues further diminish the anti-tumor effects of these drugs. Therefore, we produced a therapeutic nano drug delivery system (FA-PEG-PLA-JQ1) through encapsulating JQ1 [a small-molecule inhibitor of bromodomain containing protein 4 (BRD4)] into the folic acid (FA)-modified nanoparticle (PEG-PLA), which could prolong the half-life of JQ1 and target the tumor tissues. And then, JQ1 released from this nanoparticle could prevent OSCC growth inducing tumor cell apoptosis, inhibiting tumor angiogenesis and the polarization of M2 type macrophages. In conclusion, our date demonstrated the therapeutic benefits of FA-PEG-PLA-JQ1 against OSCC in vivo or in vitro, which could be a novel treatment strategy for OSCC in coming days.
Early pathogenesis of ischemia-reperfusion (I/R)-induced acute kidney injury (AKI) is dominated by intracellular calcium overload, which induces oxidative stress, intracellular energy metabolism disorder, inflammatory activation, and a series of pathologic cascaded reactions that are closely intertwined with self-amplifying and interactive feedback loops, ultimately resulting in cell damage and kidney failure. Currently, most nanomedicines originate from the perspective of antioxidant stress, which can only quench existing reactive oxide species (ROS) but cannot prevent the continuous production of ROS, resulting in insufficient efficacy. As a safe and promising drug, BAPTA-AM is hydrolyzed into BAPTA by intracellular esterase upon entering cells, which can rapidly chelate with overloaded Ca2+, restoring intracellular calcium homeostasis, thus inhibiting ROS regeneration at the source. Here, we designed a KTP-targeting peptide-modified yolk-shell structure of liposome–poly(ethylene glycol)methyl ether-block-poly (l-lactide-co-glycolic) (mPLGA) hybrid nanoparticles (<100 nm), with the characteristics of high encapsulation rate, high colloid stability, facile modification, and prolonged blood circulation time. Once the BA/mPLGA@Lipo-KTP was targeted to the site of kidney injury, the cholesteryl hemisuccinate (CHEMS) in the phospholipid bilayer, as an acidic cholesterol ester, was protonated in the simulated inflammatory slightly acidic environment (pH 6.5), causing the liposomes to rupture and release the BA/mPLGA nanoparticles, which were then depolymerized by intracellular esterase. The BAPTA-AM was diffused and hydrolyzed to produce BAPTA, which can rapidly cut off the malignant loop of calcium overload/ROS generation at its source, blocking the endoplasmic reticulum (ER) apoptosis pathway (ATF4–CHOP–Bax/Bcl-2, Casp-12–Casp-3) and the inflammatory pathway (TNF-α–NF-κB–IL-6 axes), thus alleviating pathological changes in kidney tissue, thereby inhibiting the expression of renal tubular marker kidney injury molecule 1 (Kim-1) (reduced by 82.9%) and also exhibiting prominent anti-apoptotic capability (TUNEL-positive ratio decreased from 40.2% to 8.3%), significantly restoring renal function. Overall, this research holds huge potential in the treatment of I/R injury-related diseases.
Second near-infrared (NIR-Ⅱ) light triggered in-situ tumor vaccination (ISTV) represents one of the most promising strategies in boosting the whole-body antitumor immunity. While most of previously developed nano-adjuvants for NIR-Ⅱ-triggered ISTV are “all-in-one” formulations, which may indiscriminately damage both the tumor cells and the immune cells, limiting the overall effect of immune response. To overcome this obstacle, we designed a “cocktail” nano-adjuvant by physically mixing hyaluronidases (HAase)-decorated gold nanostars (HA) for NIR-Ⅱ light triggered in situ production of tumor-associated antigens and CpG functionalized gold nanospheres (CA) for immune cells activation. Compared to “all-in-one” formulation, the “cocktail” nano-adjuvants displayed a significantly stronger immune response on NIR-Ⅱ light induced dendritic cells (DCs) mutation and T cells differentiation, greater effect on tumor-growth inhibition, and higher efficacy in inhibition of pulmonary metastases. What is more, increasing the molar ratio of HA to CA led to an enhanced anticancer immune responses. This study highlight the nano-adjuvant formulation effects on the treatment of tumors with multiple targets.