Molecular imaging of the tumor microenvironment

Tumor microenvironment triggered biodegradation of inorganic nanoparticles for enhanced tumor theranostics

Inorganic nanoparticles (NPs)-mediated tumor theranostics have attracted widespread attention due to their unique physicochemical properties, such as optical, electrical, magnetic, and thermal properties. In the past decade, great advancements have been made in inorganic NPs-associated drug delivery, multimodal tumor imaging, and tumor therapy. However, the potential toxicity of inorganic NPs due to their low biodegradability, background signals interference and treatment side effects limit their clinical application. Therefore, developing biodegradable and intelligent NPs is beneficial to avoid excessive metal ions deposition, specific tumor imaging and treatment. In this review, we summarize the recent advances in tumor microenvironment (TME)-triggered biodegradation of inorganic NPs accompanied by imaging signal amplification and the released ions-mediated tumor therapy. First, the feature characteristics of the TME are introduced, including mild acidity, hypoxia, overexpressed reactive oxygen species (ROS), glutathione (GSH), and enzymes et al.; then, the biodegradation of NPs in a TME-induced activation of imaging signals, such as magnetic resonance (MR) imaging and fluorescence imaging is described; furthermore, tumor therapies through "Fenton", "Fenton-like" reactions, and interference of biological effects in cells is presented. Finally, the challenges and outlook for improving the degradation efficiency, imaging, specificity and efficiency of tumor imaging and treatment are discussed.

Expression, function and clinical application of stanniocalcin-1 in cancer

The glycoprotein stanniocalcin-1 functions as a regulatory endocrine hormone that maintains the balance of calcium and phosphorus in bony fish and as a paracrine/autocrine factor involved in many physiological/pathological processes in humans, including carcinogenesis. In this review, we provide an overview of (a) the possible mechanisms through which STC1 affects the malignant properties of cancer, (b) transcriptional and post-transcriptional regulation pathways of STC1 and (c) the potential clinical relevance of STC1 as a cancer biomarker and even a therapeutic target in the future. Exploring the role of STC1 in cancer development may provide a better understanding of the tumorigenesis process in humans and may facilitate finding an effective therapeutic method against cancer.

Tuning the Brightness and Photostability of Organic Dots for Multivalent Targeted Cancer Imaging and Surgery

Specific labeling of biomarkers with bright and high photostable fluorophores is vital in fluorescent imaging applications. Here, we report a general strategy to develop single-molecule dendritic nanodots with finely tunable optical properties for in vivo fluorescent imaging. The well-defined nanodots are based on the divergent growth of biodegradable polylysine dendrimers with a fluorophore as the core. By tuning the size and surface chemistry, we obtained fluorescent nanodots with excellent brightness and photostability, favorable pharmacokinetics, and multivalent tumor-targeting capability. The nanodots provided robust, stable, long-lasting, and specific fluorescence enhancement in tumor tissue with an in situ tumor-to-normal ratio (TNR) of ∼3 and lasting over 5 days and an ex vivo TNR up to ∼17, holding considerable promise for cancer imaging and image-guided surgery. This strategy significantly improves the in vivo performance of fluorophores and can be applied to other modality imaging probes.

Polarization and function of tumor-associated macrophages mediate graphene oxide-induced photothermal cancer therapy

Polarization status of tumor-associated macrophages (TAMs) plays an essential role in tumor growth and invasion. However, emerging treatment like photothermal therapy (PTT), photodynamic therapy (PDT) paid little attention on TAMs. In recent years, photothermal therapy (PTT) has gained immense attention in the anti-tumor strategy field while the effect of PTT on macrophage polarization in a tumor microenvironment has rarely been reported. Here, we used graphene oxide (GO) combined with polyethylene glycol (PEG) as the photothermal material to induce heating effect in macrophages to define its anti-tumor effect in vitro and in vivo. Firstly, we treated the macrophage cell line RAW264.7 with near infrared (NIR) light irradiation and detected their polarization status by flow cytometric and mRNA expression analysis. Following this, we analyzed the migration and invasion ability of an osteosarcoma HOS cell line cultured in a conditioned medium (CM) that contains cytokine generated by macrophages with or without NIR treatment. Finally, we investigated the in vivo effects of NIR-induced macrophage polarization on osteosarcoma growth and invasion. GO-PEG (GP) showed great photothermal effect, thermal stability, and biocompatibility in vitro and in vivo. Photothermal materials can alleviate interleukin-4-induced M2 polarization of macrophages and modulate their anti-tumor capability. Thus, the migration and invasion capabilities of HOS cells were weakened, leading to an anti-tumor effect in a mouse subcutaneous tumor model. In conclusion, our study identified PTT treatment as an approach for preventing osteosarcoma invasion by inhibition of M2 polarization.

Response of pH-Sensitive Doxorubicin Nanoparticles on Complex Tumor Microenvironments by Tailoring Multiple Physicochemical Properties

Cellular internalization, delivery efficiency, and therapeutic efficacy of nanoparticles vary according to the microenvironmental complexity for tumor types. Adjusting their physicochemical properties, such as surface properties and size, has significant potential for dealing with such complexities. Herein, we prepare four types of pH-sensitive doxorubicin nanoparticles (DOX-D1, DOX-D2, DOX-W1, and DOX-W2 Nano) using simply changing reaction medium or reactant ratio. DOX-D1 and DOX-D2 Nano exhibit similar surface characteristics (surface coating and targeting ligand content) and different size, while both DOX-W Nano examples present similar surface characteristics and size. And they can re-self-assemble into smaller particles in blood-mimic conditions and the order of size is as follows: DOX-D1> DOX-D2 ≈ DOX-W Nano, and DOX-W Nano has a higher targeting ligand content than DOX-D Nano. Thus, the bioactivities in vitro and tumor microenvironment responses of DOX-D1, DOX-D2, and DOX-W1 are further investigated due to their different physicochemical properties. DOX-W1 Nano exhibits a higher cellular uptake, a stronger antiproliferation than DOX-D1 and DOX-D2 Nano attributed to its smaller size, and a higher targeting moiety content. Despite the similar sizes of DOX-W1 and DOX-D2, DOX-D2 Nano shows a greater in vitro blood-brain barrier (BBB) permeability related to its surface coating. Interestingly, DOX-D1 with suitable size and surface property can efficiently bypass the BBB and deliver to an intracranial glioma; in comparison DOX-W1 Nano has excellent targeting efficiency in subcutaneous tumors (glioma and breast cancer). Accordingly, DOX-D1 Nano is preferential for the treatment of intracranial glioma while DOX-W1 Nano exhibits potent killing ability for subcutaneous tumors. Our work suggests tailoring multiple physicochemical properties of nanoparticles can play a significant role in addressing tumor microenvironment complexity.

Tracking tumor radiotherapy response in vivo with Cherenkov-excited luminescence ink imaging

This study demonstrates remote imaging for in vivo detection of radiation-induced tumor microstructural changes by tracking the diffusive spread of injected intratumor UV excited tattoo ink using Cherenkov-excited luminescence imaging (CELI). Micro-liter quantities of luminescent tattoo ink with UV absorption and visible emission were injected at a depth of 2 mm into mouse tumors prior to receiving a high dose treatment of radiation. X-rays from a clinical linear accelerator were used to excite phosphorescent compounds within the tattoo ink through Cherenkov emission. The in vivo phosphorescence was detected using a time-gated intensified CMOS camera immediately after injection, and then again at varying time points after the ink had broken down with the apoptotic tumor cells. Ex vivo tumors were imaged post-mortem using hyperspectral cryo-fluorescence imaging to quantify necrosis and compared to Cherenkov-excited light imaging of diffusive ink spread measured in vivo. Imaging of untreated control mice showed that ink distributions remained constant after four days with less than 3% diffusive spread measured using full width at 20% max. For all mice, in vivo CELI measurements matched within 12% of the values estimated by the high-resolution ex vivo sliced luminescence imaging of the tumors. The tattoo ink spread in treated mice was found to correlate well with the nonperfusion necrotic core volume (R2 = 0.92) but not well with total tumor volume changes (R2 = 0.34). In vivo and ex vivo findings indicate that the diffusive spread of the injected tattoo ink can be related to radiation-induced necrosis, independent of total tumor volume change. Tracking the diffusive spread of the ink allows for distinguishing between an increase in tumor size due to new cellular growth and an increase in tumor size due to edema. Furthermore, the imaging resolution of CELI allows for in vivo tracking of subtle microenvironmental changes which occur earlier than tumor shrinkage and this offers the potential for novel, minimally invasive radiotherapy response assay without interrupting a singular clinical workflow.

Prognostic Significance of the Tumor-Stromal Ratio in Invasive Breast Cancer and a Proposal of a New Ts-TNM Staging System

Background

Previous studies have demonstrated that the tumor-stromal ratio (TSR) was an independent prognostic factor in several types of carcinomas. This study aimed at exploring the prognostic significance of the TSR in invasive breast cancer using immunohistochemistry (IHC)-stained tissue microarrays (TMAs) and integrating the TSR into the traditional tumor-node-metastasis (TNM) staging system.

Methods

The prepared 7 TMAs containing 240 patients with 480 invasive BC specimens were stained with cytokeratin (CK) by the IHC staining method. The ratio of tumor cells and stromal cells was visually assessed. TSR > 1 and TSR ≤ 1 were categorized as the high TSR (low stroma) and low TSR (high stroma) groups, respectively, and the prognostic value of the TSR at 5-year disease-free survival (5-DFS) was analyzed. A new Ts-TNM (tumor stroma-tumor-node-metastasis) staging system was established and assessed.

Results

IHC staining of CK could specifically label tumor cells with clear contrast, making it easy to manually assess TSR. High TSR (low stroma) and low TSR (high stroma) were observed in 52.5% (n = 126) and 47.5 (n = 114) of the cases, according to the division of value 1. A Kaplan-Meier analysis showed that patients in the low TSR group had a worse 5-DFS compared with patients in the high TSR group (P=0.022). Multivariable analysis indicated that the T stage (P=0.014), N status (P < 0.001), histological grade (P < 0.001), estrogen receptor status (P=0.015), and TSR (P=0.011) were independent prognostic factors of invasive BC patients. The new Ts-TNM staging system combining TSR, tumor staging, lymph node status, and metastasis staging was established. The receiver operating characteristic (ROC) curve analysis demonstrated that the ability of the Ts-TNM staging system to predict recurrence was not lower than that of the TNM staging system.

Conclusions

This study confirms that the TSR is a prognostic indicator for invasive breast cancer. The Ts-TNM staging system containing stromal and tumor information may optimize risk stratification for invasive breast cancer.

Bio responsive self-assembly of Au-miRNAs for targeted cancer theranostics

Background

MicroRNA (miRNA) therapeutics are a promising approach to cancer treatment. However, this method faces considerable challenges to achieve tissue-specific, efficient, and safe delivery of miRNAs in vivo.

Methods

Herein, we developed a miRNA delivery system based on the in situ self-assembly of Au-miRNA nanocomplexes (Au-miRNA NCs). Within the cancer microenvironment, we constructed in situ self-assembled Au-miRNA NCs by coincubating gold salt and tumor suppressor mimics, such as let-7a, miRNA-34a, and miRNA-200a.

Findings

The in vitro experiments demonstrated that characteristic in situ self-assembled Au-miRNA NCs were present in cancer cells and can be taken up to inhibit the proliferation of cancer cells effectively. Most importantly, as proven in subcutaneous tumor treatment models, Au-miRNA NCs were especially useful for accurate target imaging and tumor suppression, with significantly enhanced antitumor effects for combination therapy.

Interpretation

These observations highlight that a new strategy for the in situ biosynthesis of Au-let-7a NCs, Au-miR-34a NCs, and Au-miR-200a NCs is feasible, and this may assist in the delivery of more miRNA to tumor cells for cancer treatment. This work opens up new opportunities for the development of miRNA tumor therapy strategies.

Funding

National Natural Science Foundation of China (91753106); Primary Research & Development Plan of Jiangsu Province (BE2019716); National Key Research and Development Program of China (2017YFA0205300).

Transcriptome analysis reveals the link between lncRNA-mRNA co-expression network and tumor immune microenvironment and overall survival in head and neck squamous cell carcinoma

Background

As the sixth most common cancer worldwide, head and neck squamous cell carcinoma (HNSCC) develops visceral metastases during the advanced stage of the disease and exhibits a low five-year survival rate. The importance of tumor microenvironment (TME) in tumor initiation and metastasis is widely recognized. In addition, accumulating evidence indicates that long non-coding RNA (lncRNA) is involved in crosstalk between TME and tumor cells. However, the lncRNA-associated regulators modulating the HNSCC microenvironment and progression remain largely unknown.

Methods

The publicly available transcriptome data and matched clinical HNSCC data were collected from The Cancer Genome Atlas (TCGA). Immune scores (ISs) and stromal scores (SSs) of HNSCC TME were calculated using ESTIMATE algorithm. Weighted gene co-expression network analysis (WGCNA) was conducted to determine the co-expressed lncRNAs and protein-coding mRNAs.

Results

Results showed that the high IS HNSCC male patient subgroup exhibited improved survival. Additionally, we identified 169 lncRNAs and 825 protein-coding mRNAs that were differentially expressed in high IS HNSCC samples, with the up-regulated mRNAs displaying enrichment in immune-related biological processes. Notably, we identified a high co-expression lncRNA-mRNA module (i.e., purple module) that showed strong correlation with ISs. This module contained 79 lncRNAs and 442 mRNAs, including 26 lncRNAs and 215 mRNAs showing association between expression and male HNSCC survival. Consistently, 207 of the 215 mRNAs were up-regulated in high IS HNSCC group and were enriched in immune-related signaling pathways. Based on bioinformatics analyses and previous functional assays, certain lncRNAs (e.g., AL365361.1 and PCED1B-AS1) in the purple module likely contributed to the modification of tumor immune microenvironment (TIME) in the high IS HNSCC patients, achieved by regulating transcription of abundant immune-related genes (e.g., CCR7 and TLR8).

Conclusions

In summary, we ascertained a HNSCC male patient subgroup that displayed high ISs and good survival probability. We identified hundreds of genes with specific expression patterns in this HNSCC subgroup as well as a highly co-expressed lncRNA-mRNA module with great potential for the modulation of TIME of HNSCC. Our study provides evidence of a link between the lncRNA-associated gene network, TIME, and HNSCC progression, and highlights potential therapeutic targets for this disease.

VEGFR1-Targeted Contrast-Enhanced Ultrasound Imaging Quantification of Vasculogenic Mimicry Microcirculation in a Mouse Model of Choroidal Melanoma

Purpose

Investigate the involvement of vascular endothelial growth factor receptor 1 (VEGFR1) in vasculogenic mimicry (VM) formation in ocular melanoma, as well as whether or not VEGFR1-targeted contrast-enhanced ultrasound (CEUS) can evaluate and quantify VM perfusion and function in the ocular melanoma model.

Methods

The expression of VEGFR1 was examined using immunofluorescence, western blot, and quantitative polymerase chain reaction. VM networks were analyzed with tube formation and periodic acid Schiff staining. Targeted microbubbles (MBs) were constructed and used for targeted CEUS imaging in vivo. Comparisons were made in perfusion parameters of tumors between targeted and non-targeted CEUS imaging.

Results

VEGFR1 was highly expressed, and knockdown of VEGFR1 significantly decreased VM protein expression and disrupted VM formation in MUM-2B melanoma. VEGFR1-targeted MBs specifically bind to MUM-2B cell surfaces. CEUS with VEGFR1-targeted MBs showed significant imaging enhancement throughout the entire perfusion phase compared with CEUS with IgG MBs. VEGFR1-targeted imaging was able to detect a decrease in maximum intensity and mean transit time in VEGFR1 knockdown melanoma compared with control melanoma. The pathological VM patterns were consistent with VEGFR1-targeted CEUS findings.

Conclusions

VEGFR1 was responsible for VM network formation and was required for efficient choroidal melanoma tumor growth. This study shows that VEGFR1-targeted CEUS can track VM levels in animal models of ocular melanoma at morphological levels in vivo. This experiment is noninvasive and reproducible and indicates the possibility of real-time in vivo imaging technology for VM evaluation.

Translational Relevance

Based on our study results, VEGFR1 could prove to be a promising treatment that targets VM formation in choroidal melanoma. Our findings also suggest the potential use of VEGFR1-targeted CEUS for quantitative monitoring of VM processes at the molecular level in the future.

Enzyme-Instructed Self-Assembly for Cancer Therapy and Imaging

Enzymatic reactions and self-assembly are two fundamental attributes of cells. It is not surprising that one can use enzyme-instructed self-assembly (EISA)-the integration of enzymatic transformation and molecular self-assembly-to modulate the emergent properties of supramolecular assemblies for controlling cell behaviors. The exploration of EISA for developing cancer therapy and imaging has made considerable progress over the last five years. In this Topical Review, we discuss these exciting results and the future promise of EISA. After describing several key studies to illustrate the progress of EISA in developing cancer therapy, we discuss the use of EISA for molecular imaging. Then, we give the outlook of EISA for developing supramolecular anticancer medicine that inhibits multiple hallmark capabilities of cancer.

Association of CXCL13 and Immune Cell Infiltration Signature in Clear Cell Renal Cell Carcinoma

Clear cell renal cell carcinoma (ccRCC) is one of the most commonly diagnosed kidney tumors and is often accompanied by immune cell infiltration. In this study, we attempted to identify microenvironment-associated genes and explore the correlation between CXCL13 and tumor-infiltrating immune cells (TIICs). Gene expression profiles and their corresponding clinical information were downloaded from The Cancer Genome Atlas (TCGA) database. The ESTIMATE (Estimation of Stromal and Immune cells in Malignant Tumor tissues using Expression data) algorithm was used to calculate immune cell and stromal cell scores, according to which patients were divided into high- and low-score groups, allowing differentially expressed genes (DEGs) to be identified. Functional enrichment and PPI network analysis were used to identify the functions of the DEGs. CIBERSORT algorithm and TIMER analysis were used to evaluate the immune score. Oncomine and TCGA database were used to explore CXCL13 mRNA expression level in ccRCC. High ESTIMATE score was significantly associated with prognosis. Functional enrichment analysis clarified that DEGs were associated with T cell activation, immune response-regulating cell surface receptor signaling pathway, and positive regulation of cytokine production. PPI network was used to identify CXCL13 as a hub gene. And CIBERSORT algorithm and TIMER analysis showed that strong correlation between CXCL13 expression level and TIICs. Oncomine database was used to validate high CXCL13 expression level in ccRCC tissue, compared to normal tissues. In conclusion, we obtained a list of tumor microenvironment-related genes and identified CXCL13 as an immune response biomarker in patients with ccRCC, GSEA analysis, wound healing and transwell assays showed CXCL13 played a role in tumor migration.

Bifidobacterium spp: the promising Trojan Horse in the era of precision oncology

Selective delivery of therapeutic agents into solid tumors has been a major challenge impeding the achievement of long-term disease remission and cure. The need to develop alternative drug delivery routes to achieve higher drug concentration in tumor tissue, reduce unwanted off-target side effects and thus achieve greater therapeutic efficacy, has resulted in an explosive body of research. Bifidobacterium spp. are anaerobic, nonpathogenic, Gram-positive bacteria, commensal to the human gut that are a possible anticancer drug-delivery vehicle. In this review, we describe Bifidobacterium's microbiology, current clinical applications, overview of the preclinical work investigating Bifidobacterium's potential to deliver anticancer therapy, and review the different strategies used up to date. Finally, we discuss both current challenges and future prospects.

Cyclic RGD-Functionalized and Disulfide-Crosslinked Iodine-Rich Polymersomes as a Robust and Smart Theranostic Agent for Targeted CT Imaging and Chemotherapy of Tumor

There is tremendous interest in integrating CT imaging with chemotherapy; however, reported iodine-based nanosystems such as nanogels and nano-emulsions display typically reduced contrast coefficient, low drug loading and stability, and poor targetability. Here, cRGD-functionalized disulfide-crosslinked iodine-rich polymersomes (cRGD-XIPs) were designed as a novel, robust and smart theranostic agent and investigated for targeted CT imaging and chemotherapy of malignant tumors. Methods: cRGD-XIPs were prepared from co-self-assembly of poly(ethylene glycol)-b-poly(dithiolane trimethylene carbonate-co-iodinated trimethylene carbonate) (PEG-P(DTC-IC)) and cRGD-PEG-P(DTC-IC) block copolymers. In vitro and in vivo CT contrast effect of cRGD-XIPs was studied using α_vβ₃-overexpressing B16 melanoma as a tumor model in comparison with clinical agent iohexol. The therapeutic efficacy of doxorubicin-loaded cRGD-XIPs (cRGD-XIPs-Dox) to B16 melanoma was investigated and compared with XIPs-Dox (non-targeted), cRGD-IPs-Dox (non-crosslinked) and free Dox. Results: cRGD-XIPs were formed with 55.5 wt.% iodine and ca. 90 nm in diameter. cRGD-XIPs-Dox with a Dox loading of 15.3 wt.% bared superior colloidal stability and reduction-responsive drug release. Notably, blank cRGD-XIPs showed a maximum-tolerated dose (MTD) > 400 mg iodine equiv./kg while cRGD-XIPs-Dox had an MTD > 150 mg Dox equiv./kg, ca. 15-fold improvement over free Dox. cRGD-XIPs revealed superior CT contrast effect and achieved 46.5- and 24.0-fold better enhancement of CT imaging of B16 melanoma than iohexol at 4 h following intratumoral and intravenous injection, respectively. cRGD-XIPs-Dox displayed an elimination half-life of 6.5 h and an elevated accumulation of 6.68% ID/g in the tumors. Furthermore, cRGD-XIPs-Dox was significantly more effective than XIPs-Dox and cRGD-XPs-Dox in inhibiting growth of B16 melanoma model. Conclusion: This proof-of-concept study demonstrates that cRGD-XIPs are a robust, non-toxic and smart polymeric theranostic agent that can not only significantly enhance CT imaging of tumors but also mediate efficient tumor-targeted chemotherapy. XIPs offer a unique and safe platform for theranostic polymersomes that pre-select patients using CT imaging prior to targeted chemotherapy with the same system.

Targeting and microenvironment-improving of phenylboronic acid-decorated soy protein nanoparticles with different sizes to tumor

It is essential for nanoparticles to delivery drugs accurately and penetrate deeply to tumor. However, complicated tumor microenvironment such as elevated tumor interstitial fluid pressure (IFP) and solid stress reduces the transport efficiency of nanomedicines in tumor.

Methods: We herein report a drug delivery system of phenylboronic acid-decorated soy protein nanoparticles with the size of 30 nm, 50 nm and 150 nm. In vitro examinations including cytotoxicity, cellular uptake and penetration in multicellular tumor spheroids and in vivo observations including IFP and tumor solid stress measurements and antitumor activity were performed.

Results: It was found that phenylboronic acid moiety could endow the nanoparticles actively targeting affinity to sialic acid (SA) which overexpressed in tumor cells. Simultaneously soy protein could improve tumor microenvironment such as reduction of IFP and tumor stress. Among the soy protein nanoparticles with different sizes, 30 nm-sized nanoparticles showed the best cellular uptake and highest cytotoxicity in vitro after loading doxorubicin (DOX). In vivo, 30 nm-sized nanoparticles showed the best tumor microenvironment improvement efficiency, leading to the enhanced drug accumulation and antitumor efficiency when combination with DOX.

Conclusion: Our study introduces a bioactive nanoparticulate design strategy to actively target and significantly improve tumor microenvironment for enhanced cancer therapy.

SARI suppresses colitis-associated cancer development by maintaining MCP-1-mediated tumour-associated macrophage recruitment

SARI (suppressor of AP‐1, regulated by IFN) impaired tumour growth by promoting apoptosis and inhibiting cell proliferation and tumour angiogenesis in various cancers. However, the role of SARI in regulating tumour‐associated inflammation microenvironment is still elusive. In our study, the colitis‐dependent and ‐independent primary model were established in SARI deficiency mice and immuno‐reconstructive mice to investigate the functional role of SARI in regulating tumour‐associated inflammation microenvironment and primary colon cancer formation. The results have shown that SARI deficiency promotes colitis‐associated cancer (CAC) development only in the presence of colon inflammation. SARI inhibited tumour‐associated macrophages (TAM) infiltration in colon tissues, and SARI deficiency in bone marrow cells has no observed role in the promotion of intestinal tumorigenesis. Mechanism investigations indicated that SARI down‐regulates p‐STAT1 and STAT1 expression in colon cancer cells, following inhibition of MCP‐1/CCR2 axis activation during CAC development. Inverse correlations between SARI expression and macrophage infiltration, MCP‐1 expression and p‐STAT1 expression were also demonstrated in colon malignant tissues. Collectively, our results prove the inhibition role of SARI in colon cancer formation through regulating TAM infiltration.

Acidity-responsive shell-sheddable camptothecin-based nanofibers for carrier-free cancer drug delivery

Small molecular prodrugs that self-assemble into nanoparticles have many advantages over commonly studied nanomedicines based upon nanoscale carriers such as liposomes, micelles and polymeric nanoparticles. These carrier-free nanodrugs exhibit favorable nanoproperties without the help of a nanocarrier, and they have many unique merits, such as a simple synthetic procedure, well-defined structure and high drug loading capacity. To date, most of these carrier-free nanodrugs have been spherical and very few nonspherical nanodrugs have been synthesized and studied. Herein, we report a camptothecin (CPT) prodrug that self-assembles into nanofibers. These carrier-free CPT nanofibers have a width of approximately one hundred nanometers and a length of several micrometers. The cellular uptake and tumor penetration behaviour of these nanofibers were observed by time-lapse video microscopy. These nanofibers can rapidly enter cancer cells by penetrating the cell membrane, gradually dissolve intracellularly and efficiently release the active drug. Coating the surface of these nanofibers with a pH-responsive PEG layer improves the stability of these nanofibers and shields their positive charge to minimize nonspecific interactions. These pH-responsive nanofibers are sheddable in the acidic tumor microenvironment and deliver carried cargoes deep into tumors. Our findings demonstrate that small molecular CPT prodrugs that form nanofibers are efficient for cancer drug delivery.

Potent delivery of an MMP inhibitor to the tumor microenvironment with thermosensitive liposomes for the suppression of metastasis and angiogenesis

Metastasis is a major cause of chemotherapeutic failure and death. Degradation of a specific component of the extracellular matrix (ECM) by matrix metalloproteinases (MMPs) affects the physical barrier of the tumor microenvironment (TME) and induces metastasis. Here, lysolipid-containing thermosensitive liposomes (LTSLs) were prepared to deliver an MMP inhibitor, marimastat (MATT), to the TME to inhibit MMP activity and expression. LTSLs rapidly released their payloads at 42 °C. Compared with the saline control, MATT-LTSLs exhibited enhanced accumulation in the tumor and a 20-fold decrease in tumor growth in 4T1 tumor-bearing mice; moreover, MATT-LTSLs reduced MMP-2 and MMP-9 activity by 50% and 43%, respectively, and downregulated MMP-2 and MMP-9 expression in vivo by 30% and 43%, respectively. Most importantly, MATT-LTSL treatment caused a 7-fold decrease in metastatic lung nodules and a 6-fold reduction in microvessels inside the tumor. We believe this study provides an effective approach for the suppression of metastasis, and the use of a cytotoxic agent in combination with MATT is a potential strategy for metastatic cancer treatment.

Construction and integrated analysis of crosstalking ceRNAs networks in laryngeal squamous cell carcinoma

Background

Laryngeal squamous cell carcinoma (LSCC) is one of the most common malignant tumours of the head and neck. Recent evidence has demonstrated that lncRNAs play important roles in tumour progression and could be used as biomarkers for early diagnosis, prognosis, and potential therapeutic targets. The "competitive endogenous RNA (ceRNA)" hypothesis states that lncRNAs competitively bind to miRNAs through their intramolecular miRNA reaction elements (MREs) to construct a wide range of ceRNA regulatory networks. This study aims to predict the role of ceRNA network in LSCC, for advancing the understanding of underlying mechanisms of tumorigenesis.

Material and Methods

In this study, the functions of lncRNAs as ceRNAs in LSCC and their prognostic significance were investigated via comprehensive integrated expression profiles data of lncRNAs, mRNAs, and miRNAs obtained from The Cancer Genome Atlas (TCGA). Protein-protein interaction, gene ontology, pathway, and Kaplan-Meier curves analysis were used to profile the expression and function of altered RNAs in LSCC.

Results

As a result, 889 lncRNAs, 55 miRNAs and 1946 mRNAs were found to be differentially expressed in LSCC. These altered mRNAs were mainly involved in extracellular matrix organization, calcium signaling, and metabolic pathways. To study the regulatory function of lncRNAs, an lncRNA-mediated ceRNA network was constructed. This ceRNA network included 61 lncRNAs, seven miRNAs and seven target mRNAs. Of these RNAs, lncRNAs (TSPEAR-AS, CASK-AS1, MIR137HG, PART1, LSAMP-AS1), miRNA (has-mir-210) and mRNAs (HOXC13, STC2, DIO1, FOXD4L1) had a significant effect on the prognosis of LSCC.

Conclusion

The results of this study broaden the understanding of the mechanisms by which lncRNAs are involved in tumorigenesis. Furthermore, five lncRNAs (TSPEAR-AS, CASK-AS1, MIR137HG, PART1, LSAMP-AS1) were identified as potential prognostic biomarkers and therapeutic targets for LSCC. These results provide a basis for further experimental and clinical research.

An immune infiltration signature to predict the overall survival of patients with colon cancer

Immune infiltration of tumors has been increasingly accepted as a prognostic factor in colon cancer. Here, we aim to develop a novel immune signature, based on estimated immune landscape from tumor transcriptomes, to predict the overall survival of patients with colon cancer. The compositions of 22 immune cell subtypes from three microarray datasets were characterized with the CIBERSORT deconvolution algorithm. A prognostic immunoscore (PIS) model for overall survival prediction was established by using least absolute shrinkage and selection operator (LASSO) penalized regression analysis. A total of 17 immune cell markers were screened out in the LASSO model and were then aggregated to generate the PIS. In the training cohort (n = 490), patients with high PIS exhibited a remarkably poorer overall survival than those with low PIS. Similar results were obtained in patients with different TNM stages and in patients receiving adjunctive chemotherapy or not. Multivariate Cox regression indicated that the PIS was an independent predictor for overall survival in colon cancer (hazard ratio: 2.734, 95% confidence interval: 2.052-3.643, p < .001). The prognostic capability of PIS was also confirmed in the testing cohort (n = 245) and the entire cohort (n = 735). As for biological implications, the PIS was significantly associated with some immune checkpoints, inflammatory factors, epithelial-mesenchymal transformation regulators, and many known signaling pathways in cancer. The results of our study provide a novel and promising immune signature for overall survival prediction of patients with colon cancer.

Tumor Microenvironment and Cell Fusion

Cell fusion is a highly regulated biological process that occurs under both physiological and pathological conditions. The cellular and extracellular environment is critical for the induction of the cell-cell fusion. Aberrant cell fusion is initiated during tumor progression. Tumor microenvironment is a complex dynamic system formed by the interaction between tumor cells and their surrounding cells. Cell-cell fusion mediates direct interaction between tumor cells and their surrounding cells and is associated with tumor initiation and progression. Various microenvironmental factors affect cell fusion in tumor microenvironment and generate hybrids that acquire genomes of both parental cells and exhibit novel characteristics, such as tumor stem cell-like properties, radioresistance, drug resistance, immune evasion, and enhanced migration and invasion abilities, which are closely related to the initiation, invasion, and metastasis of tumor. The phenotypic characteristics of hybrids are based on the phenotypes of parental cells, and the fusion of tumor cells with diverse types of microenvironmental fusogenic cells is concomitant with phenotypic heterogeneity. This review highlights the types of fusogenic cells in tumor microenvironment that can fuse with tumor cells and their specific significance and summarizes the various microenvironmental factors affecting tumor cell fusion. This review may be used as a reference to develop strategies for future research on tumor cell fusion and the exploration of cell fusion-based antitumor therapies.

Extradomain-B Fibronectin-Targeted Dextran-Based Chemical Exchange Saturation Transfer Magnetic Resonance Imaging Probe for Detecting Pancreatic Cancer

A dextran-peptide conjugate was developed for magnetic resonance (MR) molecular imaging of pancreatic ductal adenocarcinoma (PDAC) through its overexpressed microenvironment biomarker, extradomain-B fibronectin (EDB-FN). This new agent consists of diamagnetic and biocompatible dextran and a targeting peptide. Dextrans can be directly detected by chemical exchange saturation transfer magnetic resonance imaging (CEST MRI) without the need for radionuclide or metallic labeling. In addition, large molecular weight dextran, dextran 10 (MW ∼ 10 kDa), provides an approximately 50 times higher sensitivity per molecule than a single glucose unit. The potential of this highly biocompatible diamagnetic probe is demonstrated in a murine syngeneic allograft PDAC tumor model. The biocompatibility and sensitivity of this new agent clearly show potential for a path to clinical translation.

Cubic versus hexagonal - effect of host crystallinity on the T1 shortening behaviour of NaGdF4 nanoparticles

Sodium gadolinium fluoride (NaGdF4) nanoparticles are promising candidates as T1 shortening magnetic resonance imaging (MRI) contrast agents due to the paramagnetic properties of the Gd3+ ion. Effects of size and surface modification of these nanoparticles on proton relaxation times have been widely studied. However, to date, there has been no report on how T1 relaxivity (r1) is affected by the different polymorphs in which NaGdF4 crystallizes: cubic (α) and hexagonal (β). Here, a microwave-assisted thermal decomposition method was developed that grants selective access to NaGdF4 nanoparticles of either phase in the same size range, allowing the influence of host crystallinity on r1 to be investigated. It was found that at 3 T cubic NaGdF4 nanoparticles exhibit larger r1 values than their hexagonal analogues. This result was interpreted based on Solomon-Bloembergen-Morgan theory, suggesting that the inner sphere contribution to r1 is more pronounced for cubic NaGdF4 nanoparticles as compared to their hexagonal counterparts. This holds true irrespective of the chosen surface modification, i.e. small citrate groups or longer chain poly(acrylic acid). Key aspects were found to be a polymorph-induced larger hydrodynamic diameter and the higher magnetization possessed by cubic nanoparticles.

Macrophage ERα promoted invasion of endometrial cancer cell by mTOR/KIF5B-mediated epithelial to mesenchymal transition

Tumor-associated macrophages (TAMs) exert tumor-promoting effects. There have been reports that estrogen receptors (ERs) are expressed on the infiltrating macrophages of endometriosis, ovarian cancer and lung cancer. However, the role of ERs in macrophages is not well characterized. In this study, we identified that ER alpha (ERα) expression on the macrophages of human endometrial cancer was positively correlated with cancer progression. Conditioned medium from selective ERα agonist-treated M2 macrophages induced the epithelial to mesenchymal transition (EMT) in endometrial cancer cells. However, this effect can be inhibited by ERα antagonist. Here, we showed that macrophages ERα-engaged abundantly produced chemokine (C-C motif) ligand 18 (CCL18), and its expression promoted the invasion of endometrial cancer cells by activating the extracellular signal-regulated kinase 1/2 pathway, whereas suppressing CCL18 abrogated these effects. Furthermore, we identified that CCL18 derived from TAMs upregulated KIF5B expression to promote EMT via activating the PI3K/AKT/mTOR signaling pathway in endometrial cancer. Overall, our findings show how ERα-engaged infiltrating macrophages initiate chronic inflammation and promote the aggressive progression of endometrial cancer cells. ERα-positive TAMs act as drivers of endometrial cancer, which may become a potential therapeutic target.

Preparation and Evaluation of ZD2 Peptide 64Cu-DOTA Conjugate as a Positron Emission Tomography Probe for Detection and Characterization of Prostate Cancer

Positron emission tomography (PET) is a sensitive modality for cancer molecular imaging. We aim to develop a PET probe for sensitive detection and risk stratification of prostate cancer by targeting an abundant microenvironment oncoprotein, extradomain-B fibronectin (EDB-FN). The probe consists of a small ZD2 peptide specific to EDB-FN and a ⁶⁴Cu-DOTA chelate. The probe was synthesized using standard solid-phase peptide chemistry and chelated to ⁶⁴Cu prior to imaging. PET images were acquired at 4 and 22 h after intravenously injecting a 200 μCi probe into mice bearing human PC3 and LNCaP tumors, which represent highly aggressive and slow-growing prostate tumors, respectively. At 4 and 22 h postinjection, tumors could be clearly identified in the PET images. A significant higher signal was observed in PC3 tumors than in LNCaP tumors at 22 h (p = 0.01). Probe accumulation was also higher in PC3 tumors at 24 h. These data demonstrated that PET molecular imaging of EDB-FN in the tumor microenvironment of prostate cancer allows efficient differentiation of PC3 and LNCaP tumors in vivo. The ZD2 peptide-targeted PET probe shows potential in the detection and characterization of high-risk prostate cancer to improve the clinical management of prostate cancer.

Clinicopathological and prognostic values of fibronectin and integrin αvβ3 expression in primary osteosarcoma

Background

Osteosarcoma is a malignant bone tumor with a high potential for lung metastasis, and the prognosis for patients with metastatic disease is very poor. The interaction between fibronectin (FN) and integrin αvβ3 in soft-tissue sarcoma promotes cell migration, invasion, and lung metastasis. This study aimed to investigate the prognostic significance of FN and αvβ3 in osteosarcoma.

Methods

Immunohistochemistry and western blotting were used to detect the expression of FN and αvβ3 in 60 osteosarcoma specimens and in 30 osteochondroma specimens. Furthermore, correlations of FN and αvβ3 with the clinicopathological features of osteosarcoma patients were analyzed using the χ² test and Fisher’s exact test. Disease-free survival and overall survival of osteosarcoma patients were assessed using the Kaplan-Meier method and Cox proportional hazards model. The predictive accuracy of the model was determined by the Harrell concordance index.

Results

FN (P < 0.05) and αvβ3 (P < 0.05) were overexpressed in osteosarcoma specimens compared with osteochondroma specimens. High FN expression was associated with a poor response to chemotherapy (P = 0.001) and poor disease-free (P < 0.001) and overall (P < 0.001) survival. High expression of αvβ3 was linked to an advanced surgical stage (P = 0.028), a poor response to chemotherapy (P = 0.002), and both poor disease-free survival (P < 0.001) and overall survival (P < 0.001). FN and αvβ3 co-expression were associated with sex (P = 0.011), an advanced surgical stage (P = 0.013), and a poor response to chemotherapy (P = 0.002). Moreover, high expression of both proteins can serve as an independent prognostic value for reduced survival time in osteosarcoma patients.

Conclusions

The results of this study suggest that FN and αvβ3 expression is associated with an unfavorable clinical outcome of osteosarcoma, and these molecules may constitute attractive therapeutic targets for osteosarcoma treatment. To improve the survival of osteosarcoma patients, further investigations are required to clarify their prognostic values in a larger population.

Electronic supplementary material

The online version of this article (10.1186/s12957-019-1566-z) contains supplementary material, which is available to authorized users.

Self-quenching synthesis of coordination polymer pre-drug nanoparticles for selective photodynamic therapy

A novel “pre-photodynamic” nanoparticles (Fe-IBDP NPs) with a tumor microenvironment (TME)-activatable PDT and good biodegradability were synthesized by self-quenching strategy.

Magnetic nanoarchitectures for cancer sensing, imaging and therapy

The use of magnetic nanoparticles for sensing and theranostics of cancer has grown substantially in the last decade. Since the pioneering studies, which reported magnetic nanoparticles for bio-applications more than fifteen years ago, nanomaterials have increased in complexity with different shapes (nanoflowers, nanospheres, nanocubes, nanostars etc.) and compositions (e.g. core-shell) of nanoparticles for an increase in the sensitivity (imaging or sensing) and efficiency through synergistic treatments such as hyperthermia and drug delivery. In this review, we describe recent examples concerning the use of magnetic nanoparticles for bio-applications, from the surface functionalization methods to the development of cancer sensors and nanosystems for magnetic resonance and other imaging methodologies. Multifunctional nanosystems (nanocomposites, core shell nanomaterials) for theranostic applications involving treatments such as hyperthermia, photodynamic therapy, targeted drug delivery, and gene silencing are also described. These nanomaterials could be the future of medicine, although their complexity raises concerns about their safety.

A Novel Near-Infrared Fluorescent Probe TMTP1-PEG4-ICG for in Vivo Tumor Imaging

Molecular imaging agents are considered to be promising tracers for tumor imaging and guided therapy. TMTP1 was screened through the FliTrx bacterial peptide display system in our laboratory previously and shown to specifically target to primary tumors and metastatic foci. In this study, small peptide TMTP1 was designed to conjugate to a near-infrared fluorescent agent ICG derivative ICG-OSu through PEG4, forming the novel probe TMTP1-PEG4-ICG. It was successfully synthesized and certified. CCK-8 assay showed that it was nontoxic to normal cells and cancerous cells. Dynamics study indicated that the probe was cleared through the liver-intestine and kidney-bladder pathway. Tumor targeting capability of this probe in vitro was evaluated on 4T1, SiHa, HeLa, S12, and HaCaT cells by flow cytometry. In vivo imaging of 4T1 and HeLa tumor-bearing mice further identified the tumor homing ability. As we had expected, the probe showed excellent affinity to cancer cells not only in vitro but also in vivo, whether in murine tumor or humanized tumor. In conclusion, TMTP1-PEG4-ICG demonstrated ideal imaging effects on tumor-bearing mice model, providing new opportunities for tumor diagnostic or guiding resection.

Progress in research on the effects of traditional Chinese medicine on the tumor microenvironment

Tumor microenvironment (TME) has received more and more attention as modern medical research has begun to understand its importance in tumorigenesis. The occurrence, development, metastasis and drug resistance of tumors are closely related to TME. TME is a complicated system, including nontumor cells, their secreted cytokines, extracellular matrix, among other components. The concepts of wholism and multitarget regulation in traditional Chinese medicine (TCM) make it well suited to the regulation of TME. In this paper, the authors reviewed the progress of TME research and the effect of TCM on TME, providing some views of Chinese medicine in antitumor research.

Imaging breast cancer using a dual-ligand nanochain particle

Nanoparticles often only exploit the upregulation of a receptor on cancer cells to enhance intratumoral deposition of therapeutic and imaging agents. However, a single targeting moiety assumes that a tumor is homogenous and static. Tumoral microenvironments are both heterogenous and dynamic, often displaying variable spatial and temporal expression of targetable receptors throughout disease progression. Here, we evaluated the in vivo performance of an iron oxide nanoparticle in terms of targeting and imaging of orthotropic mouse models of aggressive breast tumors. The nanoparticle, a multi-component nanochain, was comprised of 3–5 iron oxide nanoparticles chemically linked in a linear chain. The nanoparticle’s surface was decorated with two types of ligands each targeting two different upregulated biomarkers on the tumor endothelium, P-selectin and fibronectin. The nanochain exhibited improved tumor deposition not only through vascular targeting but also through its elongated structure. A single-ligand nanochain exhibited a ~2.5-fold higher intratumoral deposition than a spherical nanoparticle variant. Furthermore, the dual-ligand nanochain exhibited higher consistency in generating detectable MR signals compared to a single-ligand nanochain. Using a 7T MRI, the dual-ligand nanochains exhibited highly detectable MR signal within 3h after injection in two different animal models of breast cancer.

A drug-delivering-drug strategy for combined treatment of metastatic breast cancer

Treatment of metastatic cancer continues to be a huge challenge worldwide. Notably, drug nanocrystals (Ns) in nanosuspensions clearly belong to a type of nanoparticle. Therefore, a question arose as to whether these drug particles can also be applied as carriers for drug delivery. Here, we design a novel paclitaxel (PTX) nanocrystal stabilized with complexes of matrix metalloproteinase (MMP)-sensitive β-casein/marimastat (MATT) for co-delivering MATT and PTX and combined therapy of metastatic breast cancer. The prepared Ns (200 nm) with a drug-loading of >50% were potent in treatment of metastatic cancer, which markedly inhibited MMP expression and activity and greatly blocked the lung metastasis and angiogenesis. In conclusion, employing protein-drug complexes as stabilizers, Ns with dual payloads are developed and are a promising strategy for co-delivery. Furthermore, the developed Ns can target the tumor microenvironment and cancer cells and, as a result, enable efficient treatment for breast metastatic cancer.

Drug Delivery in Cancer Therapy, Quo Vadis?

The treatment of malignancies has undergone dramatic changes in the past few decades. Advances in drug delivery techniques and nanotechnology have allowed for new formulations of old drugs, so as to improve the pharmacokinetics, to enhance accumulation in solid tumors, and to reduce the significant toxic effects of these important therapeutic agents. Here, we review the published clinical data in cancer therapy of several major drug delivery systems, including targeted radionuclide therapy, antibody-drug conjugates, liposomes, polymer-drug conjugates, polymer implants, micelles, and nanoparticles. The clinical outcomes of these delivery systems from various phases of clinical trials are summarized. The success and limitations of the drug delivery strategies are discussed based on the clinical observations. In addition, the challenges in applying drug delivery for efficacious cancer therapy, including physical barriers, tumor heterogeneity, drug resistance, and metastasis, are discussed along with future perspectives of drug delivery in cancer therapy. In doing so, we intend to underscore that efficient delivery of cancer therapeutics to solid malignancies remains a major challenge in cancer therapy, and requires a multidisciplinary approach that integrates knowledge from the diverse fields of chemistry, biology, engineering, and medicine. The overall objective of this review is to improve our understanding of the clinical fate of commonly investigated drug delivery strategies, and to identify the limitations that must be addressed in future drug delivery strategies, toward the pursuit of curative therapies for cancer.

Development of new prognostic model based on pretreatment βLRI and LLRI for stage IE/IIE upper aerodigestive tract ENKTL, nasal type

To identify simple non-invasive prognostic factors for extranodal natural killer/T cell lymphoma (ENKTL), we have investigated the prognostic value of pretreatment β2-microglobin to lymphocytes ratio index (βLRI) or lactate dehydrogenase to lymphocytes ratio index (LLRI), by analyzing the retrospective data from 211 ENKTL patients. Receiver operating characteristic (ROC) curve analysis was performed to determine the cut-off value of pretreatment βLRI and LLRI. The univariate analysis indicated that Ann Arbor Stage (p = 0.008), Eastern Cooperative Oncology Group score (ECOG) (p = 0.009), International Prognostic Index (IPI) (p = 0.023), βLRI (p = 0.003), LLRI (p = 0.04), neutrophil-lymphocyte ratio index (p = 0.025) and monocyte/granulocyte to lymphocyte ratio (p = 0.030) were significantly associated with overall survival (OS) in ENKTL patients. However, multivariate analysis demonstrated that only Ann Arbor Stage (p = 0.028), βLRI (p < 0.001) and LLRI (p = 0.006) were only correlated independently with OS. Furthermore, βLRI and LLRI based new prognostic model showed improved discrimination for stage IE/IIE upper aerodigestive tract in ENKTL patients than IPI and Korean Prognostic Index. Overall, our study concluded that new βLRI-based prognosis model is useful to stratify ENKTL patients and higher βLRI and LLRI can act as independent prognostic predictor candidates in early stage ENKTL.

Nanoplatform Assembled from a CD44-Targeted Prodrug and Smart Liposomes for Dual Targeting of Tumor Microenvironment and Cancer Cells

The tumor microenvironment (TME) plays a critical role in tumor initiation, progression, invasion, and metastasis. Therefore, a therapy that combines chemotherapeutic drugs with a TME modulator could be a promising route for cancer treatment. This paper reports a nanoplatform self-assembled from a hyaluronic acid (HA)-paclitaxel (PTX) (HA-PTX) prodrug and marimastat (MATT)-loaded thermosensitive liposomes (LTSLs) (MATT-LTSLs) for the dual targeting of the TME and cancer cells. Interestingly, the prodrug HA-PTX can self-assemble on both positively and negatively charged liposomes, forming hybrid nanoparticles (HNPs, 100 nm). Triggered by mild hyperthermia, HA-PTX/MATT-LTSLs HNPs rapidly release their payloads into the extracellular environment, and the released HA-PTX quickly enters 4T1 cells through a CD44-HA affinity. The HNPs possess promoted tumor accumulation (1.6-fold), exhibit deep tumor penetration, and significantly inhibit the tumor growth (10-fold), metastasis (100%), and angiogenesis (10-fold). Importantly, by targeting the TME and maintaining its integrity via inhibiting the expression and activity of matrix metalloproteinases (>5-fold), blocking the fibroblast activation by downregulating the TGF-β1 expression (5-fold) and suppressing the degradation of extracellular matrix, the HNPs allow for significant metastasis inhibition. Overall, these findings indicate that a prodrug of an HA-hydrophobic-active compound and liposomes can be self-assembled into a smart nanoplatform for the dual targeting of the TME and tumor cells and efficient combined treatment; additionally, the co-delivery of MATT and HA-PTX with the HNPs is a promising approach for the treatment of metastatic cancer. This study creates opportunities for fabricating multifunctional nanodevices and offers an efficient strategy for disease therapy.

Oxygen Sensing, Hypoxia Tracing and in Vivo Imaging with Functional Metalloprobes for the Early Detection of Non-communicable Diseases

Hypoxia has been identified as one of the hallmarks of tumor environments and a prognosis factor in many cancers. The development of ideal chemical probes for imaging and sensing of hypoxia remains elusive. Crucial characteristics would include a measurable response to subtle variations of pO2 in living systems and an ability to accumulate only in the areas of interest (e.g., targeting hypoxia tissues) whilst exhibiting kinetic stabilities in vitro and in vivo. A sensitive probe would comprise platforms for applications in imaging and therapy for non-communicable diseases (NCDs) relying on sensitive detection of pO2. Just a handful of probes for the in vivo imaging of hypoxia [mainly using positron emission tomography (PET)] have reached the clinical research stage. Many chemical compounds, whilst presenting promising in vitro results as oxygen-sensing probes, are facing considerable disadvantages regarding their general application in vivo. The mechanisms of action of many hypoxia tracers have not been entirely rationalized, especially in the case of metallo-probes. An insight into the hypoxia selectivity mechanisms can allow an optimization of current imaging probes candidates and this will be explored hereby. The mechanistic understanding of the modes of action of coordination compounds under oxygen concentration gradients in living cells allows an expansion of the scope of compounds toward in vivo applications which, in turn, would help translate these into clinical applications. We summarize hereby some of the recent research efforts made toward the discovery of new oxygen sensing molecules having a metal-ligand core. We discuss their applications in vitro and/or in vivo, with an appreciation of a plethora of molecular imaging techniques (mainly reliant on nuclear medicine techniques) currently applied in the detection and tracing of hypoxia in the preclinical and clinical setups. The design of imaging/sensing probe for early-stage diagnosis would longer term avoid invasive procedures providing platforms for therapy monitoring in a variety of NCDs and, particularly, in cancers.

MRI relaxivity enhancement of gadolinium oxide nanoshells with a controllable shell thickness

The relaxation enhancement mechanism and MRI application of the designed core–shelled silica–Gd₂O₃ nanoparticle contrast agents were studied.

Combination curcumin and (-)-epigallocatechin-3-gallate inhibits colorectal carcinoma microenvironment-induced angiogenesis by JAK/STAT3/IL-8 pathway

Tumor microenvironment has a crucial role in cancer development and progression, whereas the mechanism of how it regulates angiogenesis is unclear. In this study, we simulated the colorectal carcinoma microenvironment by conditioned medium (CM) of colorectal carcinoma cell lines (SW620, HT-29, HCT116) supernatant or colorectal carcinoma tissue homogenate supernatant to induce normal endothelial cells (NECs). We found that colorectal carcinoma CM promoted tumor angiogenesis by coercing NECs toward tumor endothelial cells (TECs) with the activation of the JAK/STAT3 signaling pathway. Antibody array analysis showed HT-29 supernatant contained numerous angiogenesis-related proteins, especially IL-8. Interestingly, the production of IL-8 in NECs induced by HT-29 CM was also increased. We also verified the crucial role of IL-8 in promoting the CM-induced angiogenesis, as IL-8 repression by neutralizing antibody abolished the transition of NECs toward TECs. Curcumin and (-)-epigallocatechin-3-gallate (EGCG) are broadly investigated in cancer chemoprevention. However, poor bioavailability hurdles their application alone, and the mechanism of their anti-angiogenesis still need to be illuminated. Here, we found that curcumin combination with EGCG attenuated the tumor CM-induced transition of NECs toward TECs by inhibiting JAK/STAT3 signaling pathway. Furthermore, the combination of curcumin and EGCG markedly reduced tumor growth and angiogenesis in the colorectal carcinoma PDX mouse model, and the combined anti-angiogenic effect was better than that of curcumin or EGCG alone. Taken together, our findings provide a new mechanism of tumor angiogenesis, and the combination of curcumin and EGCG represents a potential anti-angiogenic therapeutic method for colorectal carcinoma.

Targeted gadofullerene for sensitive magnetic resonance imaging and risk-stratification of breast cancer

Molecular imaging of cancer biomarkers is critical for non-invasive accurate cancer detection and risk-stratification in precision healthcare. A peptide-targeted tri-gadolinium nitride metallofullerene, ZD2-Gd₃N@C80, is synthesised for sensitive molecular magnetic resonance imaging of extradomain-B fibronectin in aggressive tumours. ZD2-Gd₃N@C80 has superior r₁ and r₂ relaxivities of 223.8 and 344.7 mM⁻¹s⁻¹ (1.5 T), respectively. It generates prominent contrast enhancement in aggressive MDA-MB-231 triple negative breast cancer in mice at a low dose (1.7 µmol kg⁻¹, 1 T), but not in oestrogen receptor-positive MCF-7 tumours. Strong tumour contrast enhancement is consistently observed in other triple negative breast cancer models, but not in low-risk slow-growing tumours. The dose of the contrast agent for effective molecular MRI is only slightly higher than that of ZD2-Cy5.5 (0.5 µmol kg⁻¹) in fluorescence imaging. These results demonstrate that high-sensitivity molecular magnetic resonance imaging with ZD2-Gd₃N@C80 may provide accurate detection and risk-stratification of high-risk tumours for precision healthcare of breast cancer.

Molecular MRI is a powerful clinical tool for non-invasive detection of cancer biomarkers. Here, the authors develop a targeted peptide gadofullerene contrast agent that can sensitively distinguish between breast cancers of different aggressiveness.

Magnetic resonance molecular imaging for non-invasive precision cancer diagnosis

Magnetic resonance imaging (MRI) is a non-invasive clinical imaging modality for high-resolution imaging of soft tissues. Magnetic resonance molecular imaging (MRMI) has the potential to provide high-resolution delineation of cancer for precision medicine. However, its clinical application is hampered by the low sensitivity of contrast enhanced MRI and the lack of safe and effective targeted MRI contrast agents. Significant progress has recently been made in the design and development of novel clinically translatable targeted MRI contrast agents for MRMI of cancer. The challenges and strategies for designing the safe and effective targeted MRI contrast agents are discussed here. Some of the recent progresses in MRMI are also highlighted. These progresses provide a new paradiagm for the design and development of safe and effective MRI contrast agents for clinical translation and pave the pave for clinical application of MRMI in precision management of cancer.

Novel small peptides derived from VEGF125-136: potential drugs for radioactive diagnosis and therapy in A549 tumor-bearing nude mice

Vascular endothelial growth factor receptor (VEGFR) is a critical factor in tumor angiogenesis and has been considered a potential target for receptor-mediated radionuclide imaging and therapy. In this study, we identified two peptides (QKRKRKKSRKKH and RKRKRKKSRYIVLS) derived from VEGF125-136 that displayed high binding affinities to VEGFR and strong inhibition of A549 cell growth. 99mTc- and 188Re-labeled peptides displayed high labeling efficiency and favorable stability in saline and human plasma. At the cellular level, the radiolabeled peptides could bind with A549 cells and be internalized via the VEGFR-1-mediated pathway. 99mTc/188Re-labeled peptide was significantly accumulated at xenograft tumors, as observed with single-photon emission computed tomography (SPECT) planar imaging. Moreover, 188Re-labeled peptides significantly inhibited tumor growth, prolonged the survival time of the tumor-bearing nude mice and resulted in much more necrotic regions and apoptotic cells in the A549 xenograft tumors. These results demonstrated that these two peptides as candidate drugs for radionuclide imaging and tumor therapy.

Nonviral cancer gene therapy: Delivery cascade and vector nanoproperty integration

Gene therapy represents a promising cancer treatment featuring high efficacy and limited side effects, but it is stymied by a lack of safe and efficient gene-delivery vectors. Cationic polymers and lipid-based nonviral gene vectors have many advantages and have been extensively explored for cancer gene delivery, but their low gene-expression efficiencies relative to viral vectors limit their clinical translations. Great efforts have thus been devoted to developing new carrier materials and fabricating functional vectors aimed at improving gene expression, but the overall efficiencies are still more or less at the same level. This review analyzes the cancer gene-delivery cascade and the barriers, the needed nanoproperties and the current strategies for overcoming these barriers, and outlines PEGylation, surface-charge, size, and stability dilemmas in vector nanoproperties to efficiently accomplish the cancer gene-delivery cascade. Stability, surface, and size transitions (3S Transitions) are proposed to resolve those dilemmas and strategies to realize these transitions are comprehensively summarized. The review concludes with a discussion of the future research directions to design high-performance nonviral gene vectors.

Crosstalk between stromal cells and cancer cells in pancreatic cancer: New insights into stromal biology

Pancreatic cancer (PC) remains one of the most lethal malignancies worldwide. Increasing evidence has confirmed the pivotal role of stromal components in the regulation of carcinogenesis, invasion, metastasis, and therapeutic resistance in PC. Interaction between neoplastic cells and stromal cells builds a specific microenvironment, which further modulates the malignant properties of cancer cells. Instead of being a "passive bystander", stroma may play a role as a "partner in crime" in PC. However, the role of stromal components in PC is complex and requires further investigation. In this article, we review recent advances regarding the regulatory roles and mechanisms of stroma biology, especially the cellular components such as pancreatic stellate cells, macrophages, neutrophils, adipocytes, epithelial cells, pericytes, mast cells, and lymphocytes, in PC. Crosstalk between stromal cells and cancer cells is thoroughly investigated. We also review the prognostic value and molecular therapeutic targets of stroma in PC. This review may help us further understand the molecular mechanisms of stromal biology and its role in PC development and therapeutic resistance. Moreover, targeting stroma components may provide new therapeutic strategies for this stubborn disease.

Mass Spectrometry Imaging in Oncology Drug Discovery

Over the last decade mass spectrometry imaging (MSI) has been integrated in to many areas of drug discovery and development. It can have significant impact in oncology drug discovery as it allows efficacy and safety of compounds to be assessed against the backdrop of the complex tumour microenvironment. We will discuss the roles of MSI in investigating compound and metabolite biodistribution and defining pharmacokinetic -pharmacodynamic relationships, analysis that is applicable to all drug discovery projects. We will then look more specifically at how MSI can be used to understand tumour metabolism and other applications specific to oncology research. This will all be described alongside the challenges of applying MSI to industry research with increased use of metrology for MSI.