Localized Instillation Enables In Vivo Screening of Targeting Peptides Using One-Bead One-Compound Technology.

The One-Bead One-Compound (OBOC) library screening is an efficient technique for identifying targeting peptides. However, due to the relatively large bead size, it is challenging for the OBOC method to be applied for in vivo screening. Herein, we report an in vivo Localized Instillation Beads library (LIB) screening method to discover targeting peptides with the OBOC technique. Inspired by localized instillation, we constructed a cavity inside of a transplanted tumor of a mouse. Then, the OBOC heptapeptide library was injected and incubated inside the tumor cavity. After an efficient elution process, the retained beads were gathered, from which three MDA-MB-231 tumor-targeting heptapeptides were discovered. It was verified that the best peptide had 1.9-fold higher tumor accumulation than the commonly used targeting peptide RGD in vivo. Finally, two targeting proteins were discovered as potential targets of our targeting peptide to the MDA-MB-231 tumor. The in vivo LIB screening method expands the scope of OBOC peptide screening applications to discover targeting peptides in vivo feasibly and reliably.

Reprogramming Hypoxic Tumor-Associated Macrophages by Nanoglycoclusters for Boosted Cancer Immunotherapy.

The tumor-associated macrophages (TAMs) in intratumoral hypoxic regions are key drivers of immune escape. Reprogramming the hypoxic TAMs to antitumor phenotype holds great therapeutic benefits but remains challenging for current drugs. Here, an in situ activated nanoglycocluster is reported to realize effective tumor penetration and potent repolarization of hypoxic TAMs. Triggered by the hypoxia-upregulated matrix metalloproteinase-2 (MMP-2), the nanoglycocluster is self-assembled from the administered mannose-containing precursor glycopeptides and presents densely-arrayed mannoses to multivalently engage with mannose receptors on M2-like TAMs for efficient phenotype switch. By virtue of the high diffusivity of precursor glycopeptides due to their low molecular mass and weak affinity with TAMs in perivascular regions, the nanoglycoclusters are capable of substantially accumulating in hypoxic areas to strongly interact with local TAMs. This enables the efficient repolarization of overall TAMs with a higher rate than the small-molecule drug R848 and CD40 antibody, and beneficial therapeutic effects in mouse tumor models especially when combining with PD-1 antibody. This on-demand activated immunoagent is endowed with tumor-penetrating properties and inspires the design of diverse intelligent nanomedicines for hypoxia-related cancer immunotherapy.

A bioactivated in vivo assembly nanotechnology fabricated NIR probe for small pancreatic tumor intraoperative imaging.

Real-time imaging of the tumour boundary is important during surgery to ensure that sufficient tumour tissue has been removed. However, the current fluorescence probes for bioimaging suffer from poor tumour specificity and narrow application of the imaging window used. Here, we report a bioactivated in vivo assembly (BIVA) nanotechnology, demonstrating a general optical probe with enhanced tumour accumulation and prolonged imaging window. The BIVA probe exhibits active targeting and assembly induced retention effect, which improves selectivity to tumours. The surface specific nanofiber assembly on the tumour surface increases the accumulation of probe at the boundary of the tumor. The blood circulation time of the BIVA probe is prolonged by 110 min compared to idocyanine green. The assembly induced metabolic stability broaden the difference between the tumor and background, obtaining a delayed imaging window between 8-96 h with better signal-to-background contrast (>9 folds). The fabricated BIVA probe permits precise imaging of small sized (<2 mm) orthotopic pancreatic tumors in vivo. The high specificity and sensitivity of the BIVA probe may further benefit the intraoperative imaging in a clinical setting.

Chemical Reactions Trigger Peptide Self-Assembly in†vivo for Tumor Therapy.

Self-assembly peptide materials have promoted the development of science research including life science, optics, medicine, and catalysis over the past two decades. Especially in tumor treatment, peptide self-assembly strategies have exhibited promising potential by their high degree of biocompatibility, construction modularization, and diversity in structure controllability. Driven by physical and chemical triggers, peptides can self-assemble in vivo to form fibers, spheres, hydrogels, or ribbons to achieve predeterminate biological functions. Peptide self-assembly triggered by chemical reactions provides superior specificity and intelligent responsiveness to produce assembly-induced biological effects in target regions. Herein, from the perspective of triggers of peptide assembly, we briefly review the applications of in vivo peptide self-assembly strategies for tumor treatment, including tumor-pathology-factor-induced chemical reactions and bio-orthogonal reactions.

A Near-Infrared Peptide Probe with Tumor-Specific Excretion-Retarded Effect for Image-Guided Surgery of Renal Cell Carcinoma.

Image-guided surgery plays a crucial role in realizing complete tumor removal, reducing postoperative recurrence and increasing patient survival. However, imaging of tumor lesion in the typical metabolic organs, e.g., kidney and liver, still has great challenges due to the intrinsic nonspecific accumulation of imaging probes in those organs. Herein, we report an in situ self-assembled near-infrared (NIR) peptide probe with tumor-specific excretion-retarded (TER) effect in tumor lesions, enabling high-performance imaging of human renal cell carcinoma (RCC) and achieving complete tumor removal, ultimately reducing postoperative recurrence. The NIR peptide probe first specifically recognizes αvß3 integrin overexpressed in renal cancer cells, then is cleaved by MMP-2/9, which is up-regulated in the tumor microenvironment. The probe residue spontaneously self-assembles into nanofibers that exhibit an excretion-retarded effect in the kidney, which contributes to a high signal-to-noise (S/N) ratio in orthotopic RCC mice. Intriguingly, the TER effect also enables precisely identifying eye-invisible tiny lesions (<1 mm), which contributes to complete tumor removal and significantly reduces the postoperative recurrence compared with traditional surgery. Finally, the TER strategy is successfully employed in high-performance identification of human RCC in an ex vivo kidney perfusion model. Taken together, this NIR peptide probe based on the TER strategy is a promising method for detecting tumors in metabolic organs in diverse biomedical applications.

[Methodology improvement in background elimination in plant Cd measurement by graphite furnace atom absorption].

A problem of higher background value and lower measured Cd value exists when Cd is digested by conventional dry digestion method, measured by graphite furnace atomic absorption, and calculated with peak height numeration. This problem results in difficulty for evaluating samples with Cd contents in the neighborhood of critical values. In order to solve the problem, the present paper focused on background measurement with graphite furnace atomic absorption, modified the pre-preparation procedures of the traditional method, and screened the optimal concentration of the modifier. Results showed that addition of Mg (NO3)2 as a modifier into the samples before incineration was preferred. It could not only yield a clear solution but also reduce its background by ten times, considerably eliminating background interference. In addition, using 3% HNO3 in stead of 1 mol x L(-1) HCl as dilution for the incinerated sample could eliminate the background. The improved methods could acquire a zero concentration of measurement for the blank, re-correct the values measured by graphite furnace atomic absorption and obtain more reliable results.