Tumor Cell Uptake Research Articles

Multifunctional hybrid oncolytic virus-mimicking nanoparticles for targeted induce of tumor-specific pyroptosis and enhanced anti-tumor immune response in melanoma

Pyroptosis, a newly discovered form of programmed cell death, has emerged as a promising antitumor approach by releasing pro-inflammatory cytokines and immunogenic substances upon cell rupture. However, non-specific pyroptosis potentially causes systemic damage to healthy tissues, and the heterogeneity of tumors limits the anti-tumor effect of pyroptosis. To address these challenges, we propose a simple yet powerful method for creating multifunctional hybrid oncolytic virus-mimicking nanovesicles (HVMNVs) that possess tumor-targeting capabilities, adjuvant activity, and the ability to evade immune clearance induced by virus modification. Based on this multifunctional nanovesicle, we developed a functional nanoparticle (HVMNVs@Fe-C) that significantly enhances the tumor targetability and cell uptake efficiency of the extremely small iron oxide nanoparticles (ESIONPs) and carbonyl cyanide m-chlorophenyl hydrazone (CCCP), leading to rapid tumor pyroptosis. More importantly, HVMNVs@Fe-C ingeniously achieves a synergistic effect by incorporating the adjuvantic and tumor-targeting properties of oncolytic viruses with the cell lytic and pro-inflammatory functions of pyroptosis in a single nanoparticle. This leads to a cascade of specific anti-tumor immune responses and reprogramming of the immunosuppressive tumor microenvironment, resulting in excellent tumor inhibition efficacy against primary melanoma growth and pulmonary metastasis. Overall, our novel strategy offers considerable promise for precisive targeted delivery and cancer immunotherapy.

MPEG-PDLLA polymeric micelles loading a novel pyridazinone derivative IMB5036 for improving anti-tumor activity in hepatocellular carcinoma

IMB5036 (N7) is a hydrophobic pyridazinone compound with antitumor activity, identified in our laboratory. To increase its water solubility, we utilized nanomicelles encapsulating N7 in this study. Monomethyl polyethylene glycol-polylactic acid (mPEG-PDLLA) polymer micelles were employed as drug carrier, and their characterizations were measured. IMB5036/mPEG-PDLLA (N7M) exhibited a particle size of approximately 28 nm and a polydispersity index of around 0.2. The optimal dosage ratio of N7 to mPEG-PDLLA was determined to be 10:90, with an encapsulation rate of (93.66 ± 3.94)% and a drug loading efficiency of (9.59 ± 1.26)%. The morphology of N7 micelles was spherical, with a uniform particle size distribution and good water solubility of approximately 1.17 mg/ml. Compared to the free drug, N7M demonstrated a higher tumor cell uptake rate and slow release profile, while maintaining similar tumor cell killing ability and apoptosis-inducing capacity. In vivo experiments confirmed that the nanomicelles improved tumor targeting, and N7M effectively inhibited tumor growth in a hepatoma xenograft model. Overall, N7M represents a successful injectable nanomicelle formulation for the treatment of hepatoma.

Deciphering sources of PET signals in the tumor microenvironment of glioblastoma at cellular resolution.

Various cellular sources hamper interpretation of positron emission tomography (PET) biomarkers in the tumor microenvironment (TME). We developed an approach of immunomagnetic cell sorting after in vivo radiotracer injection (scRadiotracing) with three-dimensional (3D) histology to dissect the cellular allocation of PET signals in the TME. In mice with implanted glioblastoma, translocator protein (TSPO) radiotracer uptake per tumor cell was higher compared to tumor-associated microglia/macrophages (TAMs), validated by protein levels. Translation of in vitro scRadiotracing to patients with glioma immediately after tumor resection confirmed higher single-cell TSPO tracer uptake of tumor cells compared to immune cells. Across species, cellular radiotracer uptake explained the heterogeneity of individual TSPO-PET signals. In consideration of cellular tracer uptake and cell type abundance, tumor cells were the main contributor to TSPO enrichment in glioblastoma; however, proteomics identified potential PET targets highly specific for TAMs. Combining cellular tracer uptake measures with 3D histology facilitates precise allocation of PET signals and serves to validate emerging novel TAM-specific radioligands.

Quantitative imaging of doxorubicin diffusion and cellular uptake in biomimetic gels with human liver tumor cells

Novel tumor-on-a-chip approaches are increasingly used to investigate tumor progression and potential treatment options. To improve the effect of any cancer treatment it is important to have an in depth understanding of drug diffusion, penetration through the tumor extracellular matrix and cellular uptake. In this study, we have developed a miniaturized chip where drug diffusion and cellular uptake in different hydrogel environments can be quantified at high resolution using live imaging. Diffusion of doxorubicin was reduced in a biomimetic hydrogel mimicking tissue properties of cirrhotic liver and early stage hepatocellular carcinoma (373 ± 108 µm2/s) as compared to an agarose gel (501 ± 77 µm2/s, p = 0.019). The diffusion was further lowered to 256 ± 30 µm2/s (p = 0.028) by preparing the biomimetic gel in cell media instead of phosphate buffered saline. The addition of liver tumor cells (Huh7 or HepG2) to the gel, at two different densities, did not significantly influence drug diffusion. Clinically relevant and quantifiable doxorubicin concentration gradients (1–20 µM) were established in the chip within one hour. Intracellular increases in doxorubicin fluorescence correlated with decreasing fluorescence of the DNA-binding stain Hoechst 33342 and based on the quantified intracellular uptake of doxorubicin an apparent cell permeability (9.00 ± 0.74 × 10–4 µm/s for HepG2) was determined. Finally, the data derived from the in vitro model were applied to a spatio-temporal tissue concentration model to evaluate the potential clinical impact of a cirrhotic extracellular matrix on doxorubicin diffusion and tumor cell uptake. Graphical abstract

High-Load Gemcitabine Inorganic-Organic Hybrid Nanoparticles as Image-Guided Tumor-Selective Drug-Delivery System To Treat Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) has a devastating prognosis without effective treatment options. Thus, there is an urgent need for more effective and safe therapies. Here, we present inorganic-organic hybrid nanoparticles (GMP-IOH-NPs) as novel drug-delivery system for the selective delivery of extraordinarily high concentrations of gemcitabine monophosphate (GMP) not only to the primary tumor but also to metastatic sites. GMP-IOH-NPs have a composition [ZrO]2+ [GMP]2- with GMP as drug anion (76% of total IOH-NP mass). Multiscale fluorescence imaging confirms an efficient uptake in tumor cells, independent of the activity of the human-equilibrative-nucleoside transporter (hENT1), being responsible for gemcitabine (GEM) transport into cells and a key factor for GEM resistance. Delivering already phosphorylated GMP via GMP-IOH-NPs into tumor cells also allows to overcome cellular resistance induced by the down-regulation of deoxycytidine kinase. GMP-IOH-NPs show high accumulation in tumor lesions and only minor liver trapping when given intraperitoneally. GMP-IOH-NPs result in a higher anti-tumor efficacy compared to free GEM and is further enhanced applying cetuximab-functionalized GMP-CTX-IOH-NPs. By maximizing the therapeutic benefits with high drug load, tumor-specific delivery, minimizing undesired side effects, overcoming mechanisms of chemoresistance, and preventing systemic GEM inactivation, we anticipate GMP-IOH-NPs to have a high chance to significantly improve current PDAC-patient outcome. This article is protected by copyright. All rights reserved.

Enhancing anti-tumor therapy with agmatine-cholesterol conjugate liposomes: in vitro and in vivo evidence.

In this study, we synthesized a novel compound, agmatine-cholesterol conjugate (AG-Chol), to enhance the anti-tumor activity of drug-loaded liposomes. We replaced cholesterol with AG-Chol in preparing doxorubicin hydrochloride (DOX) liposomes by using an active loading method for DOX. We assessed the physical and chemical properties of the resulting AG-Liposomes and evaluated their efficacy in vitro and in vivo. The results showed that AG-Liposomes were stable with high encapsulation efficiency. Compared with the control liposomes, AG-Liposomes exhibited a slower drug release rate in the release medium at pH 6.8. The in vitro cell experiments demonstrated that AG-Liposomes had higher tumor cell uptake rate, stronger migration inhibition rate, higher apoptosis rate, better anti-clonogenic ability, and higher lysosome escape ability than the control liposomes. In vivo distribution results demonstrate that liposomes prepared with AG-Chol instead of cholesterol can significantly enhance their tumor targeting abilities and reduce their distribution to non-targeted sites. In vivo tumor suppression experiments showed that AG-Liposomes had a higher tumor suppression rate than the control liposomes without causing apparent toxicity to normal tissues, as evidenced by histological staining. Therefore, substituting cholesterol with AG-Chol in the preparation of liposomes can result in enhanced lysosome escape, improved tumor targeting, and increased efficacy of anti-tumor drugs.

A novel self-assembled nanoplatform based on retrofitting poloxamer 188 for triple-negative breast cancer targeting treatment

Poloxamer 188 is a widely used pharmaceutical excipient, which can be found in a variety of drug formulations. In this study, a novel self-assembled nanoplatform was developed for active targeting of folate receptor-overexpressing triple-negative breast cancer. This platform, FPP NPs, was prepared by the retrofitted poloxamer 188 derivatives, resulting in nanoparticles with an appropriate size (< 100 nm), good stability, and satisfactory biocompatibility. Cellular uptake and in vivo distribution studies showed that the FPP NPs had strong tumor cell uptake and active targeting capabilities. Furthermore, docetaxel (DTX) was loaded into FPP NPs in this research. The resulting DTX/FPP NPs exhibited high drug encapsulation efficiency and drug loading capacity, and could rapidly release DTX under slightly acidic conditions, significantly increasing the antitumor activity of the encapsulated drug both in vitro and in vivo. In addition, DTX/FPP NPs could significantly decrease the hepatotoxicity and nephrotoxicity of DTX. Therefore, this drug delivery nanoplatform, based on retrofitted poloxamer 188 with self-assembly properties in aqueous solution and active targeting capabilities to tumors, may provide a promising approach for targeted treatment of triple-negative breast cancer.

Programmable Peptides Activated Macropinocytosis for Direct Cytosolic Delivery.

Bioactive macromolecules show great promise for the treatment of various diseases. However, the cytosolic delivery of peptide-based drugs remains a challenging task owing to the existence of multiple intracellular barriers and ineffective endosomal escape. To address these issues, we herein report programmable self-assembling peptide vectors to amplify cargo internalization into the cytoplasm through receptor-activated macropinocytosis. Programmable self-assembling peptide vector-active HER2 signaling induced the receptor-activated macropinocytosis pathway, achieving efficient uptake in tumor cells. Shrinking macropinosomes accelerated the process of assembly dynamics and formed nanostructures in the cytoplasm to increase peptide-based cargo accumulation and retention. Inductively coupled plasma mass spectrometry quantitative analysis indicates that the Gd delivery efficiency in tumor tissue through the macropinocytosis pathway was improved 2.5-fold compared with that through the use of active targeting molecular delivery. Finally, compared with nanoparticles and active targeting delivery, the delivery of bioactive peptide drugs through the self-assembly of peptide vectors maintains high drug activity (the IC50 decreased 2-fold) in the cytoplasm and achieves effective inhibition of tumor cell growth. Programmable self-assembling peptide vectors represent a promising platform for the intracellular delivery of diverse bioactive drugs, including molecular drugs, peptides, and biologics. This article is protected by copyright. All rights reserved.

Intermittent Fasting Primes the Tumor Microenvironment and Improves Nanomedicine Delivery in Hepatocellular Carcinoma.

Fasting has many health benefits, including reduced chemotherapy toxicity and improved efficacy. It is unclear how fasting affects the tumor microenvironment (TME) and tumor-targeted drug delivery. Here the effects of intermittent (IF) and short-term (STF) fasting are investigated on tumor growth, TME composition, and liposome delivery in allogeneic hepatocellular carcinoma (HCC) mouse models. To this end, mice areinoculated either subcutaneously or intrahepatically with Hep-55.1C cells and subjected to IF for 24 d or to STF for 1 d. IF but not STF significantly slows down tumor growth. IF increases tumor vascularization and decreases collagen density, resulting in improved liposome delivery. In vitro, fasting furthermore promotes the tumor cell uptake of liposomes. These results demonstrate that IF shapes the TME in HCC towards enhanced drug delivery. Finally, when combining IF with liposomal doxorubicin treatment, the antitumor efficacy of nanochemotherapy isfound to be increased, while systemic side effects arereduced. Altogether, thesefindings exemplify that the beneficial effects of fasting on anticancer therapy outcomes go beyond modulating metabolism at the molecular level.

GPP-TSAIII nanocomposite hydrogel-based photothermal ablation facilitates melanoma therapy

ABSTRACT Background Photothermal therapy (PTT) is a promising cancer treatment, but its application is limited by low photoconversion efficiency. In this study, we aimed to develop a novel graphene oxide (GO)-based nanocomposite hydrogel to improve the bioavailability of timosaponin AIII (TSAIII) while maximizing PTT efficacy and enhancing the antitumor effect. Methods GO was modified via physical cross-linking with polyvinyl alcohol. The pore structure of the gel was adjusted by repeated freeze-thawing and the addition of polyethylene glycol 2000 to obtain a nanocomposite hydrogel (GPP). The GPP loaded with TSAIII constituted a GPP-TSAIII drug delivery system, and its efficacy was evaluated by in vitro cytotoxicity, apoptosis, migration, and uptake analyses, and in vivo antitumor studies. Results The encapsulation rate of GPP-TSAIII was 66.36 ± 3.97%, with slower in vitro release and higher tumor cell uptake (6.4-fold) compared to TSAIII. GPP-TSAIII in combination with PTT showed better bioavailability and antitumor effects in vivo than did TSAIII, with a 1.9-fold higher tumor suppression rate than the TSAIII group. Conclusions GPP is a potential vehicle for delivery of TSAIII-like poor water-soluble anticancer drugs. The innovative PTT co-delivery system may serve as a safe and effective melanoma treatment platform for further anticancer translational purposes.

Application of tumor pH/hypoxia-responsive nanoparticles for combined photodynamic therapy and hypoxia-activated chemotherapy.

Introduction: Cancer selectivity, including targeted internalization and accelerated drug release in tumor cells, remains a major challenge for designing novel stimuli-responsive nanocarriers to promote therapeutic efficacy. The hypoxic microenvironment created by photodynamic therapy (PDT) is believed to play a critical role in chemoresistance. Methods: We construct dual-responsive carriers (DANPCT) that encapsulate the photosensitizer chlorin e6 (Ce6) and hypoxia-activated prodrug tirapazamine (TPZ) to enable efficient PDT and PDT-boosted hypoxia-activated chemotherapy. Results and discussion: Due to TAT masking, DANPCT prolonged payload circulation in the bloodstream, and selective tumor cell uptake occurred via acidity-triggered TAT presentation. PDT was performed with a spatially controlled 660-nm laser to enable precise cell killing and exacerbate hypoxia. Hypoxia-responsive conversion of the hydrophobic NI moiety led to the disassembly of DANPCT, facilitating TPZ release. TPZ was reduced to cytotoxic radicals under hypoxic conditions, contributing to the chemotherapeutic cascade. This work offers a sophisticated strategy for programmed chemo-PDT.

Abstract 4891: Ifinatamab deruxtecan (I-DXd), a novel B7-H3-targeting antibody-drug conjugate, demonstrates efficient payload delivery into tumor through target-dependent internalization

Abstract Ifinatamab deruxtecan (I-DXd; DS-7300) is a novel ADC which consists of an anti-B7-H3 antibody linked with a DNA topoisomerase I inhibiting anti-tumor agent, DXd. I-DXd has demonstrated potent anti-tumor activity in B7-H3-positive preclinical cancer models and showed early signs of promising clinical efficacy in patients with heavily pretreated, advanced solid tumors. ADCs are postulated to exert cytotoxicity specifically in tumors that express the target antigen via target-specific uptake of the compound. Accordingly, effective action of an ADC depends on multiple dynamic steps including antigen-specific binding, internalization, trafficking to lysosomes, linker cleavage and payload release, as well as payload potency. The goal of this research was to characterize I-DXd molecular dynamics in preclinical tumor cell models by investigating the relationship among target expression and dynamics, its translocation to lysosomes, lysosomal enzyme-mediated linker cleavage, and payload release after I-DXd treatment. As a result, I-DXd demonstrated target dependent internalization, efficient trafficking to lysosomes, and subsequent payload release in the studied tumor cell lines. Payload release levels generally correlated with target expression in vitro using a panel of cell lines with varying levels of B7-H3 expression. Also, in cell-line derived xenograft models, tumor tissue payload concentration corresponded to I-DXd binding at the cell membrane. These results suggest the importance of cell surface B7-H3 expression and ADC dynamics that lead to payload release in target expressing tumors to exert anti-tumor activity in non-clinical model. In addition to target-dependent uptake in tumor cells, it was observed in viable human lung tumor slices that B7-H3 was also expressed in several non-tumor cells including cancer-associated fibroblasts, endothelial cells, and macrophages in the tumor microenvironment and I-DXd was shown to be internalized in these B7-H3-expressing non-tumor cells. In summary, this pre-clinical study characterizes the relationship between B7-H3 expression in the tumor microenvironment and I-DXd molecular dynamics. Our results support developing I-DXd as a targeted therapy against advanced solid tumors known to overexpress B7-H3. Citation Format: Len Katsumata, Tsuneo Deguchi, Jun Hasegawa, Michiko Yamato, Yumi Nishiya, Akiko Watanabe, Tomoyo Honda, Megumi Minami, Naomi Kasanuki, Takanori Maejima, Sumie Muramatsu, Monika Herrmann, Nina Schulte, Gernot Polier, Xuya Wang, Takanori Yoshida, Nanae Izumi, Xiaozhong Qian, Toshinori Agatsuma, Kenji Nakamaru. Ifinatamab deruxtecan (I-DXd), a novel B7-H3-targeting antibody-drug conjugate, demonstrates efficient payload delivery into tumor through target-dependent internalization. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4891.

Abstract 2419: A multimodel preclinical platform to evaluate photodynamic therapy as a strategy to reduce local recurrence in myxofibrosarcoma and osteosarcoma

Abstract Sarcomas are heterogeneous and rare malignant tumors that develop from connective tissues. Myxofibrosarcoma (MFS) and Osteosarcoma (OS) are the main representative subtypes of Soft tissues and Bone sarcomas. Conventional treatment consists of surgical resection and neo/adjuvant chemotherapy. However, a challenging clinical feature is a high local recurrence rate, calling for the development of novel strategies to eradicate MFS and OS. Fluorescence-guided surgery (FGS), coupled with photodynamic therapy (PDT), enables to detect and eradicate malignant tissues using a light-sensitive photosensitizer (PS). These compounds could be retained by neoplastic cells to a greater extent than by healthy tissue. Thus, when photoactivated, they lead to cancer cell death, minimizing normal tissues toxicity. The project aims to provide a preclinical proof of concept of FGS and PDT for MFS and OS, allowing us to pave the way for a more effective treatment strategy. A multimodel preclinical platform of MFS and OS comprising 2D, 3D-collagen based scaffold was developed. A MFS stabilized cell line (IM-MFS-1) and four OS cell lines (Saos-2, U-2 OS, MG-63, 143B) were used. NIH-3T3 fibroblast cell line was used as healthy counterpart. We tested a panel of synthetic PSs: Toluidine Blue, 5-Aminolevulinic Acid hydrochloride (ALA), Methylene Blue, Chlorin e6 (Ce6), Pheophorbide a (Pba) and Al(III) Phthalocyanine Chloride Tetrasulfonic Acid (AlPcS4) that can be photoactivated with light in the 630-660 nm wavelengths’ range. The PSs were ranked on (a) selective uptake by tumor cells, respect to healthy cells and (b) the cytotoxic effect, after photoactivation. PSs cell uptake was evaluated by Countess II FL automated cell counter. Cytotoxicity was evaluated by WST-1 and Presto Blue assays. For each PS we determined the highest concentration, causing less than 50% dark toxicity in IM-MFS-1, OS cell lines and fibroblast NIH-3T3, seeded in 2D and 3D collagen-based models. Then, we evaluated the cell viability upon light irradiation (λ=630 or 660 nm; 10 mW/cm^2, 5 min). For all PSs, dark toxicity was very low. However, only Ce6 was effectively uptaken by tumor cells (% uptake &amp;gt; 60%) and not by NIH-3T3 cells (% uptake = 27%). Moreover, upon photoactivation, Ce6 induced significantly higher cell death in cancer cells as compared to NIH-3T3 cells, e.g. 1-3% cell viability in tumor cells and 76% cell viability in NIH-3T3. Results from our multimodel platform highlight PDT as a powerful strategy for the treatment of MFS and OS. Among the screened PSs, Ce6 is the most promising, showing a remarkable selectivity in tumor cells uptake and cytotoxicity. To increase the clinical significance of our approach, we will confirm its efficacy in patient-derived primary cultures; xenograft zebrafish in vivo embryos will be used to evaluate how PDT affects the disease aggressiveness and metastatic potential. Citation Format: Chiara Spadazzi, Micaela Pannella, Chiara Bellotti, Elisa Martella, Silvia Vanni, Alessandro De Vita, Chiara Liverani, Giacomo Miserocchi, Claudia Cocchi, Chiara Calabrese, Valentina Fausti, Roberto Casadei, Federica Pieri, Ania Naila Guerrieri, Giovanni Martinelli, Greta Varchi, Enrico Lucarelli, Laura Mercatali, Toni Ibrahim. A multimodel preclinical platform to evaluate photodynamic therapy as a strategy to reduce local recurrence in myxofibrosarcoma and osteosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2419.

A self-amplified ferroptosis nanoagent that inhibits the tumor upstream glutathione synthesis to reverse cancer chemoresistance

Ferroptosis has recently become an attractive strategy to combat the chemoresistance of cancer cells, but the intracellular ferroptosis defense system greatly challenges the efficient ferroptosis induction. Herein, we report a ferrous metal-organic framework-based nanoagent (FMN) that inhibits the intracellular upstream glutathione synthesis and induces self-amplified ferroptosis of cancer cells, for reversing chemoresistance and boosting chemotherapy. The FMN is loaded with SLC7A11 siRNA (siSLC7A11) and chemotherapeutic doxorubicin (DOX), which shows enhanced tumor cell uptake and retention, thus ensuring the effective DOX delivery and tumor intracellular iron accumulation. Importantly, the FMN simultaneously catalyzes the iron-dependent Fenton reaction and triggers the siSLC7A11-mediated suppression of upstream glutathione synthesis for intracellularly self-amplified ferroptosis, which further inhibits P-glycoprotein activity for DOX retention, and regulates the expression of Bcl-2/Bax to reverse the apoptotic resistance state of tumor cells. The FMN-mediated ferroptosis is also demonstrated in ex vivo patient-derived tumor fragment platform. Consequently, FMN successfully reverses cancer chemoresistance and achieves a highly efficient in vivo therapeutic efficacy in MCF7/ADR tumor-bearing mice. Our study provides a self-amplified ferroptosis strategy via inhibiting intracellular upstream glutathione synthesis, which is effective to reverse cancer chemoresistance.

Eradicating the tumor "seeds": nanomedicines-based therapies against cancer stem cells.

Cancer stem cells (CSCs), a small subpopulation of cells with high tumorigenesis and strong intrinsic drug resistance, exhibit self-renewal and differentiation abilities. CSCs play a crucial role in tumor progression, drug resistance, recurrence and metastasis,and conventional therapy is not enough to eradicate them. Therefore, developing novel therapies targeting CSCs to increase drug sensitivity and preventing relapse is essential. The objective of this review is to present nanotherapies that target and eradicate the tumor "seeds". Evidence was collected and sorted from the literature ranging from 2000 to 2022, using appropriate keywords and key phrases as search terms within scientific databases such as Web of Science, PubMed and Google Scholar. Nanoparticle drug delivery systems have been successfully applied to gain longer circulation time, more precise targeting capability and better stability during cancer treatment. Nanotechnology-based strategies that have been used to target CSCs, include (1) encapsulating small molecular drugs and genes by nanotechnology, (2) targeting CSC signaling pathways, (3) utilizing nanocarriers targeting for specific markers of CSCs, (4) improving photothermal/ photodynamic therapy (PTT/PDT), 5)targeting the metabolism of CSCs and 6) enhancing nanomedicine-aided immunotherapy. This review summarizes the biological hallmarks and markers of CSCs, and the nanotechnology-based therapies to kill them. Nanoparticle drug delivery systems are appropriate means for delivering drugs to tumors through enhanced permeability and retention (EPR) effect. Furthermore, surface modification with special ligands or antibodies improves the recognition and uptake of tumor cells or CSCs. It is expected that this review can offer insights into features of CSCs and the exploration of targeting nanodrug delivery systems.

Glycopolymer-Based Hydrogels Impair Energy Metabolism via Delivering Mannose and Depleting Glucose for Tumor Suppression

Carbohydrates serve as a key biomacromolecule, not only as the major building blocks in living organisms, but also as intermediates in energy metabolism via glycolysis. The quest for developing a carbohydrate-based macromolecular system to interfere with aberrant energy metabolism of tumors is a challenging topic. Here we report a class of artificial glycopolymers containing phenolic hydroxyl-functionalized segments that can be cross-linked to form hydrogels by the enzymatic cascade reaction using glucose oxidase (GOD) and horseradish peroxidase (HRP). Glycopolymer-based hydrogels can deliver and sustainably release the antiglycolytic agent mannose at the tumor site; meanwhile, glucose is exhausted gradually during the course of gelation. Glucose uptake and hyperactive glycolysis of tumor cells are concurrently blocked by the enzyme cascade and mannose, respectively, as validated by synergistic tumor suppression in vitro. Finally, the superiority of glycopolymer-based hydrogels loading mannose and enzyme cascade is evaluated in a murine tumor model, demonstrating the ability to impair energy metabolism and retard tumor growth. This work allows glycopolymer-based biomaterials to be promising in intervening energy metabolism for tumor eradication.

ROS-responsive Galactosylated-nanoparticles with Doxorubicin Entrapment for Triple Negative Breast Cancer Therapy.

Triple negative breast cancer (TNBC) is one of the most aggressive tumors with high metastasis and mortality, which constitutes 15~20% of all breast cancers. Chemotherapy remains main therapeutic option in the treatment of patients with TNBC. We developed reactive oxygen species (ROS)-responsive galactosylated nanoparticles (DOX@NPs) as an efficiently targeted carrier for doxorubicin (DOX) delivery to inhibit the growth of TNBC in vitro and in vivo. DOX@NPs were composed of polyacrylate galactose and phenylboronic derivatives conjugation. The in vitro cytotoxicity, cellular uptake, cell apoptosis and cycle distribution of tumor cells treated with different formulations were investigated. Meanwhile in vivo biodistribution and antitumor effects were investigated in a 4T1 tumor-bearing mouse model. DOX@NPs showed good ROS responsiveness and rapid DOX release in the presence of H2O2. Furthermore, our data suggested that DOX@NPs could effectively trigger tumor cells apoptosis and cycle arrest, efficiently accumulate into tumor sites, and suppress tumor growth without adverse side effects. Our results suggested DOX@NP with potent potential as a promising nanocarrier for TNBC therapy, which deserved further investigation for other cancer treatment.

Inhibitory Effect of Tanshinone IIA Nanomicelles on Tumor Growth and Angiogenesis in Mice with Cervical Carcinoma Transplantation

In recent years, traditional Chinese medicine (TCM), represented by tanshinone (Tas) and ganoderan polysaccharides, has attracted the attention of many scientists due to its mild effect of inhibiting tumors. In this research, poly-gamma-glutamic acid (γ-PGA) was degraded into small molecule γ-PGA fragments by high-temperature acidolysis, and L-phenylalanine ethylester (L-PAE) was combined with small molecule γ-PGA fragments to generate γ-PGA-LA by dehydration condensation. The material was mixed with fat-soluble Tas IIA to form PL-Tas IIA nanomicelles (NMs). In addition to physical characterization, the in vitro biological activity of the material was detected to establish a tumor-bearing nude mouse model, which was inoculated with cervical cancer HeLa cells. The nude mouse models were grouped, and the effect of NMs on the growth of transplanted tumors was observed by intraperitoneal injection. The results revealed that the nanoparticle size was approximately 139.6±3.8 nm, and it had a good EPR effect, which was conducive to passive targeted therapy of tumors. The polydispersity coefficient and zeta potential were 0.138±0.005 and 33.6±1.6 mV, respectively. The NM was cocultured with the cells under various concentration conditions, and the cell survival rate was more than 85%. The tumor cell uptake performance of the NM was ideal, and the cell uptake ratio reached 71.62% at 60 min, as determined by flow cytometry. An in vivo tumor test demonstrated that PL-Tas IIA had a favorite tumor inhibition effect. The tumor-bearing nude mouse model showed that the prepared NMs can inhibit tumor growth, induce angiogenesis of xenografts, and further induce tumor cell apoptosis, further verifying that the prepared NMs can inhibit cervical cancer tumor growth.

Towards Radiolabeled EGFR-Specific Peptides: Alternatives to GE11.

The human epidermal growth factor receptor (EGFR) is closely related to several cancer-promoting processes and overexpressed on a variety of tumor types, rendering it an important target structure for the imaging and therapy of several malignancies. To date, approaches to develop peptidic radioligands able to specifically address and visualize EGFR-positive tumors have been of limited success. Most of the attempts were based on the lead GE11, as this peptide was previously described to be a highly potent EGFR-specific agent. However, since it has recently been shown that GE11 exhibits an insufficient affinity to the EGFR in monomeric form to be suitable as a basis for the development of tracers based on it, in the present work we investigated which other peptides might be suitable as lead structures for the development of EGFR-specific peptidic radiotracers. For this purpose, we developed 68Ga-labeled radioligands based on the peptides D4, P1, P2, CPP, QRH, EGBP and Pep11, having been described before as EGFR-specific. In addition, we also tested three truncated versions of the endogenous EGFR ligand hEGF (human epidermal growth factor) with respect to their ability to specifically target the EGFR with high affinity. Therefore, chelator-modified labeling precursors of the mentioned peptides were synthesized, radiolabeled with 68Ga and the obtained radioligands were evaluated for their hydrophilicity/lipophilicity, stability against degradation by human serum peptidases, in vitro tumor cell uptake, and receptor affinity in competitive displacement experiments on EGFR-positive A431 cells. Although all NODA-GA-modified (NODA-GA: (1,4,7-triazacyclononane-4,7-diyl)diacetic acid-1-glutaric acid) labeling precursors could be obtained more or less efficient in yields between 5 and 74%, the 68Ga-radiolabeling proved to be unsuccessful for two of the three truncated versions of hEGF ([68Ga]Ga-8 and [68Ga]Ga-9), producing several side-products. For the other agents [68Ga]Ga-1-[68Ga]Ga-7, [68Ga]Ga-10 and [68Ga]Ga-11, high radiochemical yields and purities of ≥98% and molar activities of up to 114 GBq/µmol were obtained. In the assay investigating the radiopeptide susceptibilities against serum peptidase degradation, the EGBP-based agent demonstrated a limited stability with a half-life of only 66.4 ± 3.0 min, whereas the other tracers showed considerably higher stabilities of up to an 8000 min half-life. Finally, all radiotracer candidates were evaluated in terms of tumor cell internalization and receptor binding potential on EGFR-positive A431 cell. In these experiments, all developed agents failed to show an EGFR-specific tumor cell uptake or a relevant EGFR-affinity. By contrast, the positive controls tested under identical conditions, [125I]I-hEGF and hEGF demonstrated the expected high EGFR-specific tumor cell uptake (33.6% after 1 h, being reduced to 1.9% under blocking conditions) and affinity (IC50 value of 15.2 ± 3.3 nM). Thus, these results indicate that none of the previously described peptidic agents developed for EGFR targeting appears to be a reasonable choice as a lead structure for the development of radiopeptides for targeting of EGFR-positive tumors. Likewise, the tested truncated variants of the endogenous hEGF do not seem to be promising alternatives for this purpose.

Silencing the Catalase Gene with SiRNA for Enhanced Chemodynamic Therapy.

Chemodynamic therapy (CDT) has been emerging as a promising strategy for cancer treatment. But the CDT efficiency is restricted by the insufficient intracellular hydrogen peroxide (H2O2) level. Herein, we present a method for H2O2 accumulation in tumor cells by silencing the catalase (CAT) gene with siRNA to achieve enhanced CDT. Cu-siRNA nanocomposites are fabricated by self-assembly of Cu2+ and CAT siRNA and then modified with hyaluronic acid (HA) for active tumor targeting. After tumor cell uptake, the released Cu2+ is reduced by highly expressed glutathione (GSH) to Cu+, which then catalyzes H2O2 to produce toxic hydroxyl radicals (•OH) to kill tumor cells. CAT siRNA can efficiently silence the CAT mRNA to inhibit the consumption of H2O2, resulting in H2O2 accumulation. The Cu2+-mediated GSH elimination and siRNA-induced endogenous H2O2 enrichment both potentiate CDT. Cu-siRNA@HA exhibits good biocompatibility and therapeutic efficiency. This work thus paves a new way to supply H2O2 in CDT and may hold potential for clinical application.