CT26 Tumor Research Articles

CaCO3 based proton nanosponge to potentiate immune checkpoint blockade therapy by synergistically reversing tumor immunosuppression

Tumor acidity presents one of the leading causes of tumor immunosuppression (e.g., exhaustion of effector T cells), thereby remarkably attenuating the potency of current immune checkpoint blockade (ICB) therapy in controlling tumor progression. Here, we report that calcium carbonate encapsulated with copolymers of poly(lactic-co-glycolic acid) (PLGA) and PLGA-poly(ethylene glycol) (PLGA-PEG) can work as a proton nanosponge to neutralize tumor acidity by reacting with protons post intravenous administration. The obtained CaCO3@PLGA NPs can thus promote the reinvigoration of both exhausted CD8+ T cells and innate antitumor immunity. As a result, CaCO3@PLGA NP administration could potentiate the therapeutic efficacies of three ICB therapies toward both CT26 and B16F10 tumor xenografts by preventing exhaustion of CD8+ T cells and activating innate antitumor immunity. Furthermore, we further demonstrate that intratracheal administration of CaCO3@PLGA NPs effectively suppressed lung metastasis of B16F10 melanoma when synergized with systemic anti-PD-1 administration. This work highlights that CaCO3 nanoparticles could be an effective yet safe nanomedicine to generally reinforce ICB therapies toward diverse types of tumors by reversing tumor immunosuppression, promising for future clinical translation.

Nanoscale Hafnium Metal-Organic Frameworks Enhance Radiotherapeutic Effects by Upregulation of Type I Interferon and TLR7 Expression.

Recent preclinical and clinical studies have highlighted the improved outcomes of combination radiotherapy and immunotherapy. Concurrently, the development of high-Z metallic nanoparticles as radiation dose enhancers has been explored to widen the therapeutic window of radiotherapy and potentially enhance immune activation. In this study, folate-modified hafnium-based metal-organic frameworks (HfMOF-PEG-FA) are evaluated in combination with imiquimod, a TLR7 agonist, as a well-defined interferon regulatory factor (IRF) stimulator for local antitumor immunotherapy. The enhancement of radiation dose deposition by HfMOF-PEG-FA and subsequent generation of reactive oxygen species (ROS) deregulates cell proliferation and increases apoptosis. HfMOF-PEG-FA loaded with imiquimod (HfMOF-PEG-FA@IMQ) increases DNA double-strand breaks and cell death, including apoptosis, necrosis, and calreticulin exposure, in response to X-ray irradiation. Treatment with this multipronged therapy promotes IRF stimulation for subsequent interferon production within tumor cells themselves. The novel observation is reported that HfMOF itself increases TLR7 expression, unexpectedly pairing immune agonist and receptor upregulation in a tumor intrinsic manner, and supporting the synergistic effect observed with the γH2AX assay. T-cell analysis of CT26 tumors following intratumoral administration of HfMOF-PEG-FA@IMQ with radiotherapy reveals a promising antitumor response, characterized by an increase in CD8+ and proliferative T cells.

Insight into oral amphiphilic cyclodextrin nanoparticles for colorectal cancer: comprehensive mathematical model of drug release kinetic studies and antitumoral efficacy in 3D spheroid colon tumors.

Colorectal cancer (CRC) is the third most diagnosed cancer type globally and ranks second in cancer-related deaths. With the current treatment possibilities, a definitive, safe, and effective treatment approach for CRC has not been presented yet. However, new drug delivery systems show promise in this field. Amphiphilic cyclodextrin-based nanocarriers are innovative and interesting formulation approaches for targeting the colon through oral administration. In our previous studies, oral chemotherapy for colon tumors was aimed and promising results were obtained with formulation development studies, mucin interaction, mucus penetration, cytotoxicity, and permeability in 2D cell culture, and furthermore in vivo antitumoral and antimetastatic efficacy in early and late-stage colon cancer models and biodistribution after single dose oral administration. This study was carried out to further elucidate oral camptothecin (CPT)-loaded amphiphilic cyclodextrin nanoparticles for the local treatment of colorectal tumors in terms of their drug release behavior and efficacy in 3-dimensional tumor models to predict the in vivo efficacy of different nanocarriers. The main objective was to build a bridge between formulation development and in vitro phase and animal studies. In this context, CPT-loaded polycationic-β-cyclodextrin nanoparticles caused reduced cell viability in CT26 and HT29 colon carcinoma spheroid tumors of mice and human origin, respectively. In addition, the release profile, which is one of the critical quality parameters in new drug delivery systems, was investigated mathematically by release kinetic modeling for the first time. The overall findings indicated that the strategy of orally targeting anticancer drugs such as CPT with positively charged poly-β-CD-C6 nanoparticles to colon tumors for local and/or systemic efficacy is a promising approach.

Low-Molecular-Weight β-1,3-1,6-Glucan Derived from Aureobasidium pullulans Exhibits Anticancer Activity by Inducing Apoptosis in Colorectal Cancer Cells.

β-glucan, a plant polysaccharide, mainly exists in plant cell walls of oats, barley, and wheat. It is attracting attention due to its high potential for use as functional foods and pharmaceuticals. We have previously reported that low-molecular-weight Aureobasidium pullulans-fermented β-D-glucan (LMW-AP-FBG) could inhibit inflammatory responses by inhibiting mitogen-activated protein kinases and nuclear factor-κB signaling pathways. Bases on previous results, the objective of the present study was to investigate the therapeutic potential of LMW-AP-FBG in BALB/c mice intracutaneously transplanted with CT-26 colon cancer cells onto their backs. Daily intraperitoneal injections of LMW-AP-FBG (5 mg/kg) for two weeks significantly suppressed tumor growth in mice bearing CT-26 tumors by reducing tumor proliferation and inducing apoptosis as compared to phosphate buffer-treated control mice. In addition, LMW-AP-FBG treatment reduced the viability of CT-26 cells in a dose-dependent manner by inducing apoptosis with loss of mitochondrial transmembrane potential and increased activated caspases. Taken together, LMW-AP-FBG exhibits anticancer properties both in vivo and in vitro.

Engineered indocyanine green and PD-L1 inhibitors co-loaded perfluorochemical double-layered nanodroplets offer effective photoimmunotherapy against colorectal cancer

Colorectal cancer (CRC) ranks the 3rd most common cancer and is the 2nd leading cause of cancer death worldwide, indicating that an effective therapeutic strategy is still urgently desired nowadays. In this study, an emerging indocyanine green (ICG) and anti-programmed cell death ligand 1 monoclonal antibodies (αPD-L1) co-loaded perfluorocarbon double-layer nanodroplets named IPLPNDs were developed for photoimmunotherapy of CRC. The IPLPNDs are able to stabilize the αPD-L1 in the nanocarriers and generate hyperthermia as well as significantly enhanced production of singlet oxygen compared to equal dose of free ICG upon NIR irradiation. Furthermore, the IPLPNDs + NIR can dose-dependently eradicate CT26 cells and subsequently inhibit PD-L1 bioactivity of the survived cells in vitro. Meanwhile, expression levels of HMGB1 and CRT, the two immunogenic cell death (ICD) markers, from the survived cells were elevated 24 h after NIR exposure. Through the animal study, we further demonstrated that the IPLPNDs containing 20-μM ICG and 3-μg/mL αPD-L1 in combination with 1-min NIR irradiation can effectively arrest the growth of CT26 tumor in the mice without generating organ damage, by which the tumor size was merely increased by 56 % while that without drug treatment can be tremendously expanded by 15 folds after 10 days. Moreover, the remained tumors treated by IPLPNDs + NIR indeed showed the least PD-L1 and highest CD8 expressions compared to all the other settings, illustrating the significance of immunogenicity of tumor microenvironment on anticancer efficacy. We reason that such tumor inhibition was carried out by phototherapy followed by ICD-enhanced immunotherapy, a two-stages anticancer process in vivo. Taken together, we anticipate that the developed IPLPND is highly applicable for use in the clinical CRC treatment.

Drug-loaded microbubble delivery system to enhance PD-L1 blockade immunotherapy with remodeling immune microenvironment

BackgroundAlthough programmed cell death protein 1 (PD-1)/ programmed cell death-ligand protein 1 (PD-L1) checkpoint blockade immunotherapy demonstrates great promise in cancer treatment, poor infiltration of T cells resulted from tumor immunosuppressive microenvironment (TIME) and insufficient accumulation of anti-PD-L1 (αPD-L1) in tumor sites diminish the immune response. Herein, we reported a drug-loaded microbubble delivery system to overcome these obstacles and enhance PD-L1 blockade immunotherapy.MethodsDocetaxel (DTX) and imiquimod (R837)-loaded microbubbles (RD@MBs) were synthesized via a typical rotary evaporation method combined with mechanical oscillation. The targeted release of drugs was achieved by using the directional "bursting" capability of ultrasound-targeted microbubble destruction (UTMD) technology. The antitumor immune response by RD@MBs combining αPD-L1 were evaluated on 4T1 and CT26 tumor models.ResultsThe dying tumor cells induced by DTX release tumor-associated antigens (TAAs), together with R837, promoted the activation, proliferation and recruitment of T cells. Besides, UTMD technology and DTX enhanced the accumulation of αPD-L1 in tumor sites. Moreover, RD@MBs remolded TIME, including the polarization of M2-phenotype tumor-associated macrophages (TAMs) to M1-phenotype, and reduction of myeloid-derived suppressor cells (MDSCs). The RD@MBs + αPD-L1 synergistic therapy not only effectively inhibited the growth of primary tumors, but also significantly inhibited the mimic distant tumors as well as lung metastases.ConclusionPD-L1 blockade immunotherapy was enhanced by RD@MBs delivery system.

Targeted Degradation of PD-L1 and Activation of the STING Pathway by Carbon-Dot-Based PROTACs for Cancer Immunotherapy.

Proteolysis targeting chimeras (PROTACs) technology is an emerging approach to degrade disease-associated proteins. Here, we report carbon-dot (CD)-based PROTACs (CDTACs) that degrade membrane proteins via the ubiquitin-proteasome system. CDTACs can bind to programmed cell death ligand 1 (PD-L1), recruit cereblon (CRBN) to induce PD-L1 ubiquitination, and degrade them with proteasomes. Fasting-mimicking diet (FMD) is also used to enhance the cellular uptake and proteasome activity. More than 99 % or 90 % of PD-L1 in CT26 or B16-F10 tumor cells can be degraded by CDTACs, respectively. Furthermore, CDTACs can activate the stimulator of interferon genes (STING) pathway to trigger immune responses. Thus, CDTACs with FMD treatment effectively inhibit the growth of CT26 and B16-F10 tumors. Compared with small-molecule-based PROTACs, CDTACs offer several advantages, such as efficient membrane protein degradation, targeted tumor accumulation, immune system activation, and in vivo detection.

Targeting m6A reader YTHDF1 augments antitumour immunity and boosts anti-PD-1 efficacy in colorectal cancer

ObjectiveThe role of N6-methyladenosine (m6A) in tumour immune microenvironment (TIME) remains understudied. Here, we elucidate function and mechanism of YTH N6-methyladenosine RNA binding protein 1 (YTHDF1) in colorectal cancer (CRC)...

CEACAM1 Marks Highly Suppressive Intratumoral Regulatory T Cells for Targeted Depletion Therapy.

Regulatory T cells (Tregs) exert immunosuppressive functions and hamper antitumor immune responses in the tumor microenvironment. Understanding the heterogeneity of intratumoral Tregs, and how it changes with tumor progression, will provide clues regarding novel target molecules of Treg-directed therapies. From 42 patients with renal cell carcinoma and 5 patients with ovarian cancer, immune cells from tumor and peripheral blood were isolated. We performed multicolor flow cytometry and RNA-sequencing to characterize the phenotypes and heterogeneity of intratumoral Tregs. In vitro functional assays were performed to evaluate suppressive capacity of Tregs and effect of carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1)-mediated depletion. The CT26 tumor model was used to evaluate the association between intratumoral Tregs and tumor growth, and examine the in vivo role of CEACAM1+ intratumoral Tregs on antitumor immunity. We found that CEACAM1 was selectively expressed on intratumoral Tregs, whereas its expression on peripheral Tregs or other immune cells was low. The CEACAM1+ intratumoral Tregs accumulated with tumor progression, whereas the CEACAM1- subset did not. Notably, we found that CEACAM1 marked intratumoral Tregs that exhibited highly suppressive and activated phenotypes with substantial clonal expansion. Depletion of CEACAM1-expressing cells from tumor-infiltrating leukocytes led to increased effector functions of tumor-infiltrating T cells. Moreover, CEACAM1+ cell depletion further enhanced anti-PD-1-mediated reinvigoration of exhausted CD8+ T cells. CEACAM1 marks highly suppressive subset of intratumoral Tregs, and can be a target for selective depletion of intratumoral Tregs. These results may inform future studies on CEACAM1-mediated depletion in patients with cancer.

Mitochondria-Targeting and Multiresponsive Nanoplatform Based on AIEgens for Synergistic Chemo-Photodynamic Therapy and Enhanced Immunotherapy.

Although photodynamic therapy (PDT) has become an attractive strategy for cancer treatment, its clinical application still suffers from some limitations, including insufficient delivery of photosensitizers, hypoxic tumor environment, and the development of PDT resistance. To address these limitations, a new class of mitochondria-targeting and fluorinated polymer with aggregation-induced emission characteristics was fabricated to sensitize PDT and co-deliver chemotherapeutic drugs. The amphiphilic fluoropolymer was able to efficiently carry oxygen and SN-38 (the active metabolite of irinotecan) and self-assemble into multifunctional micellar nanoparticles (SN-38-TTCF@O2 NPs). Upon internalization into tumor cells, these NPs could successfully escape lysosomes, selectively target mitochondria, efficiently produce reactive oxygen species (ROS) under light irradiation, and release drugs in response to ROS. In the HCT116 tumor xenograft model, they preferentially accumulated in tumor tissue and significantly alleviated tumor hypoxia, resulting in synergistic chemo-PDT efficacy without distinct toxicity. Furthermore, the nanoscale chemo-PDT induced immunogenic cell death, promoted the recruitment and activation of cytotoxic T lymphocytes, and ultimately augmented the anti-tumor efficacy of anti-PD-1 antibody in the murine CT26 tumor model. These results may provide novel insights into the development of efficient chemo-PDT nanomedicine to improve the outcome of immunotherapy.

Maitake α-glucan promotes differentiation of monocytic myeloid-derived suppressor cells into M1 macrophages

AimsMyeloid-derived suppressor cells (MDSCs) are major components of the tumor microenvironment and systemically accumulate in tumor-bearing hosts and patients with cancer, facilitating cancer progression. Maitake macromolecular α-glucan YM-2A, isolated from Grifola frondosa, inhibits tumor growth by enhancing immune responses. The present study investigated the effects of YM-2A on the immunosuppressive potential of MDSCs. Main methodsYM-2A was orally administered to CT26 tumor-bearing mice, and the number of immune cells in the spleen and tumor was measured. Splenic MDSCs isolated from the CT26 tumor-bearing mice were treated with YM-2A and co-cultured with T cells to measure their inhibitory effect on T cell proliferation. For adoptive transfer of monocytic MDSCs (M-MDSCs), YM-2A-treated M-MDSCs mixed with CT26 cells were implanted subcutaneously in the mice to measure the tumor growth rate. Key findingsYM-2A selectively reduced the accumulation of M-MDSCs but not that of polymorphonuclear MDSCs (PMN-MDSCs) in CT26 tumor-bearing mice. In tumor tissues, YM-2A treatment induced the polarity of immunostimulatory M1-phenotype; furthermore, it increased the infiltration of dendritic, natural killer, and CD4+ and CD8+ T cells. YM-2A treatment of purified M-MDSCs from CT-26 tumor-bearing mice induced dectin-1-dependent differentiation into M1 macrophages. YM-2A-treated M-MDSCs lost their inhibitory activity against proliferation and activation of CD8+ T cells. Furthermore, adoptive transfer of M-MDSCs treated with YM-2A inhibited CT26 tumor growth. SignificanceYM-2A promotes the differentiation of M-MDSCs into immunostimulatory M1 macrophages, thereby enhancing the efficacy of cancer immunotherapy.

Redaporfin Development for Photodynamic Therapy and its Combination with Glycolysis Inhibitors.

Photodynamic therapy (PDT) remains an underutilized treatment modality in oncology. Many efforts have been dedicated to the development of better photosensitizers, better formulations and delivery methods, rigorous planning of light dose distribution in tissues, mechanistic insight, improvement of treatment protocols and combinations with other therapeutic agents. Hopefully, progress in all these fields will eventually expand the use of PDT. Here we offer a brief review of our own contribution to the development of a photosensitizer for PDT - redaporfin - currently in Phase II clinical trials, and present data on its combination with two glycolysis inhibitors: 2-deoxyglucose and 3-bromopyruvate. We show that 3-bromopyruvate is more cytotoxic to a carcinoma cell line (CT26) than to a normal fibroblast (3T3) cell line, and that this selectivity is maintained in the invitro combination with redaporfin-PDT. This combination was investigated in BALB/c mice with large subcutaneous CT26 tumors and it is shown that the cure rate in the combination is higher (33% cures) than in PDT (11% cures) or in 3-bromopyruvate (no cures) alone. The combination of redaporfin-PDT with 3-bromopyruvate illustrates the potential of combination therapies and how PDT benefits can be enhanced by systemic drugs with complementary targets.

Nanoformulation of the K-Ras(G12D)-inhibitory peptide KS-58 suppresses colorectal and pancreatic cancer-derived tumors

Single amino acid mutations of Ras occur in 30% of human cancers. In particular, K-Ras(G12D) has been detected in the majority of intractable colorectal and pancreatic cancers. Although efforts to target K-Ras(G12D) are currently underway, no effective drugs are available. We previously found that the K-Ras(G12D)-inhibitory bicyclic peptide KS-58 exhibits antitumor activity against syngeneic colon and orthotopic grafted pancreatic tumors; however, pristine KS-58 is difficult to handle because of low water solubility and it requires frequent administration to obtain sufficient antitumor activity. In this study, we used a nanoformulation of KS-58 prepared with the highly biocompatible surfactant Cremophor® EL (CrEL) to improve water solubility and reduce the dosing frequency. Nanoformulations of KS-58 with CrEL dramatically improved its water solubility and increased its stability. Weekly intravenous administration of KS-58 nanoparticles (NPs) suppressed the growth of CT26 and PANC-1 cell-derived tumors in vivo, and fluorescent bioimaging indicated that the NP-encapsulated near-infrared fluorescent probe indocyanine green selectively accumulated in the tumor and was safely excreted through the kidneys following intravenous injection. Histopathological analysis of CT26 tumors and Western blotting of PANC-1 tumors revealed that KS-58 NPs reduced ERK phosphorylation, a downstream signal of K-Ras(G12D). Our results suggest that KS-58 NPs represent a novel therapeutic agent for treating colorectal and pancreatic cancers.

Using a zebrafish xenograft tumor model to compare the efficacy and safety of VEGFR-TKIs.

We constructed a zebrafish xenograft tumor model to compare and quantify the antiangiogenic efficacy and safety of nine vascular endothelial growth factor receptor-tyrosine kinase inhibitors (VEGFR-TKIs), axitinib, lenvatinib, pazopanib, apatinib, cabozantinib, sunitinib, semaxanib, sorafenib, and regorafenib, in parallel. CT26 and GL261 tumor cells were implanted into the perivitelline space of Tg (flk1: eGFP) zebrafish to construct a xenograft tumor model. VEGFR-TKIs' antiangiogenic efficacy was quantified using AngioTool software, and the median effective dose (ED50) was calculated. The toxicity was evaluated by calculating the median lethal dose (LD50) and gross morphological changes. Cardiac toxicity was further assessed by heart rate, heart rhythm, the distance between the sinus venosus (SV) and bulbus arteriosus (BA), and pericardial edema. Using the zebrafish xenograft tumor model, we found that all nine VEGFR-TKIs exhibited antiangiogenic abilities, but the effectiveness of semaxanib was worse than that of other VEGFR-TKIs. Meanwhile, the zebrafish toxicity assay showed that all tested VEGFR-TKIs were associated with cardiac-related toxicity, especially apatinib and axitinib, which caused serious pericardial edema in zebrafish at relatively low concentrations. A narrow therapeutic window was found for most VEGFR-TKIs, and the simultaneous occurrence of toxic effects of semaxanib was recognized. Our findings showed the potential of using a zebrafish xenograft tumor model to accelerate VEGFR-TKI screening and further the development of more efficient and less toxic VEGFR-TKIs.

TNFR2 deficiency impairs the growth of mouse colon cancer.

Objective: Tumor necrosis factor (TNF) receptor type II (TNFR2) is expressed by a wide spectrum of tumor cells including colon cancer, non-Hodgkin lymphoma, myeloma, renal carcinoma and ovarian cancer, and its exact role remains to be fully understood. In this study, we examined the effect of genetic ablation of TNFR2 on in vitro and in vivo growth of mouse MC38 and CT26 colon cancer cells. Methods: CRISPR/Cas9 technology was used to knockout TNFR2 on mouse MC38 and CT26 colon cancer cells. In vitro growth and colony formation of wild-type (W.T.) and TNFR2 deficiency of MC38 and CT26 cells, as well as the potential mechanism, was studied. The growth of W.T. and TNFR2 deficient MC38 and CT26 tumors in mice and intratumoral CD8 CTLs were also examined. Results: TNFR2 deficiency impaired in vitro proliferation and colony formation of cancer cells. This was associated with the inhibition of protein kinase B (AKT) phosphorylation and enhanced autophagy-induced cell death. Moreover, deficiency of TNFR2 also markedly impaired in vivo growth of MC38 or CT26 in the syngeneic C57BL/6 mice or BALB/c mice, respectively, accompanied by the decrease in soluble TNFR2 levels in the circulation and the increase in the number of tumor-infiltrating IFNγ+ CD8 cells. Conclusion: TNFR2 plays a role in the growth of mouse colon cancers. Our study provides further experimental evidence to support the development of TNFR2 antagonistic agents in the treatment of cancer.

Babao Dan Alleviates Cancer Cachexia in Mice Via Inhibiting IL-6/STAT3 Signaling Pathway.

Cancer cachexia is a common but severe condition that causes muscle wasting, body weight loss, and progressive functional impairment, affecting over 50% of cancer patients. Currently, there are no effective treatments that can alleviate cachexia, and hence the discovery of new therapeutics that can effectively prevent or even reverse cancer cachexia is crucial. Babao Dan (BBD) is a Traditional Chinese Medicine (TCM) formula that has been used clinically in combating various cancers, however, its therapeutic potential in alleviating cancer cachexia remains unexplored. Our current study aims to determine the anti-cachectic effects of BBD treatment in alleviating cancer cachexia, as well as determining the underlying mechanisms involved. Mouse models of cancer cachexia were induced via implantation of CT26 colon adenocarcinoma cells, and the anti-cachectic effects and mechanisms of BBD were determined via examinations of body weight and muscle mass, as well as serum and muscle markers of cachexia and muscle atrophy. CT26 tumor implantation reduced in the rapid occurrence of cancer cachexia characterized by marked reductions in body weight and muscle mass, functional decrease in muscle function and accelerated deaths. BBD administration not only demonstrated robust anti-cachectic ability via preventing decreases in body weight, muscle mass, and muscle atrophy, but also markedly prolonged survival. The effects of BBD in alleviating cancer cachexia and its associated adverse effects were due to its ability in preventing the activation of IL-6/STAT3 signaling post-CT26 tumor implantation. Our findings demonstrated the robust ability of BBD in preventing cancer cachexia and alleviating the main cachexia-induced symptoms as well as prolonging survival via inhibiting activation of IL-6/STAT3 signaling pathway. Therefore, our study demonstrating the strong anti-cachectic effects of BBD in mice may provide a theoretical basis for the use of BBD as a safe and effective drug in the treatment of cancer cachexia.

Bioinspired nanovehicle of furoxans-oxaliplatin improves tumoral distribution for chemo-radiotherapy.

The spatiotemporal distribution of therapeutic agents in tumors remains an essential challenge of radiation-mediated therapy. Herein, we rationally designed a macrophage microvesicle-inspired nanovehicle of nitric oxide donor-oxaliplatin (FO) conjugate (M-PFO), aiming to promote intratumor permeation and distribution profiles for chemo-radiotherapy. FO was responsively released from M-PFO in intracellular acidic environments, and then be activated by glutathione (GSH) into active oxaliplatin and NO molecules in a programmed manner. M-PFO exhibited notable accumulation, permeation and cancer cell accessibility in tumor tissues. Upon radiation, the reactive peroxynitrite species (ONOO-) were largely produced, which could diffuse into regions over 400μm away from the tumor vessels and be detectable after 24h of radiation, thereby exhibiting superior efficacy in improving the spatiotemporal distribution in tumors versus common reactive oxygen species (ROS). Moreover, M-PFO mediated chemo-radiotherapy caused notable inhibition of tumor growth, with an 89.45% inhibition in HT-29 tumor models and a 92.69% suppression in CT-26 tumor models. Therefore, this bioinspired design provides an encouraging platform to improve intratumor spatiotemporal distribution to synergize chemo-radiotherapy.

Design, synthesis and biological evaluation of quercetin derivatives as novel β-catenin/B-cell lymphoma 9 protein−protein interaction inhibitors

The β-catenin/B-cell lymphoma 9 (BCL9) protein-protein interaction (PPI) is a potential target for the suppression of hyperactive Wnt/β-catenin signaling that is vigorously involved in cancer initiation and development. Herein, we first described quercetin and its derivatives had potential inhibitory effects on β-catenin/BCL9 PPI. The most potent compound, quercetin-3′-O-(4-methylpiperazine-1-yl) propyl (C1), directly binded with β-catenin and disrupted the β-catenin/BCL9 interaction in both the protein level and the cellular context. C1 also effectively inhibited colorectal cancer in vitro and showed better selectivity in inhibiting hyperactive Wnt/β-catenin signaling cells like CT26 and HCT116. And we further confirmed that C1 could inhibit CT26 tumor growth in vivo and regulate the tumor immune microenvironment. This study provides a good chemical probe to explore β-catenin-related biology and a drug-like quercetin derivative as novel β-catenin/BCL9 PPI inhibitors for further drug development.

Theranostic Cancer Treatment Using Lentinan-Coated Selenium Nanoparticles and Label-Free CEST MRI.

Selenium nanoparticle (SeNP)-based nanotherapeutics have become an emerging cancer therapy, while effective drug delivery remains a technical hurdle. A theranostic approach, through which imaging companions are integrated with SeNPs, will allow image-guided drug delivery and, therefore, is highly desirable. Traditional methods require the chemical conjugation of imaging agents to the surface of nanoparticles, which may impede the later clinical translation. In this study, we developed a label-free strategy in which lentinan-functionalized SeNPs (LNT-SeNPs) are detected using MRI by the hydroxyl protons carried on LNT molecules. The in vitro phantom study showed that LNT and LNT-SeNPs have a strong CEST signal at 1.0 ppm apart from the water resonance, suggesting an in vivo detectability in the µM concentration range. Demonstrated on CT26 colon tumor cells, LNT-SeNPs exert a strong anticancer effect (IC50 = 4.8 μM), prominently attributed to the ability to generate intracellular reactive oxygen species. However, when testing in a mouse model of CT26 tumors, administration of LNT-SeNPs alone was found unable to deliver sufficient drugs to the tumor, leading to poor treatment responses. To improve the drug delivery, we co-injected LNT-SeNPs and TNF-α, a previously reported drug that could effectively damage the endothelial cells in the tumor vasculature, thereby increasing drug delivery to the tumor. Our results revealed a 75% increase in the intratumoral CEST MRI signal, indicating a markedly increased delivery efficiency of LNT-SeNPs when combined with TNF-α. The combination therapy also resulted in a significantly enhanced treatment outcome, as revealed by the tumor growth study. Taken together, our study demonstrates the first label-free, SeNP-based theranostic system, in which LNT was used for both functional surface coating and CEST MRI signal generating. Such a theranostic LNT-SeNP system is advantageous because it requires chemical labeling and, therefore, has high biocompatibility and low translatable barriers.

Theranostics through Utilizing Cherenkov Radiation of Radioisotope Zr-89 with a Nanocomposite Combination of TiO2 and MnO2.

Cherenkov radiation (CR) derived from the decay of diagnostic and therapeutic radionuclides is currently being studied by the scientific community to determine if these emissions can be harnessed for cancer detection and therapy. While Cherenkov luminescence imaging (CLI) has been studied in the preclinical and clinical settings, Cherenkov radiation-induced cancer therapy (CRICT) is a relatively new area of research that harnesses the emitted photons to kill cancer cells through free radical generation and DNA damage. Nanoparticles seem well suited for developing a theranostic platform that would allow researchers to visualize therapy delivery and also generate the reactive oxygen species necessary to kill cancer cells. Herein, we report the preparation of an 89Zr-TiO2-MnO2 nanocomposite that incorporates transferrin onto the nanoparticle surface to enhance cancer cell growth inhibition. The incorporation of the positron emission tomography (PET) radioisotope 89Zr (half-life: 3.3 days) allowed for the detection of the nanoparticle using PET and for the creation of Cherenkov emissions that interacted with the nanoparticle surface to generate free radicals for therapy delivery. After preparation, these systems were observed to be stable in various media and provided excellent tumor growth control after being intratumorally injected into mice bearing CT-26 tumors. These results demonstrate that a therapeutically efficient CRICT platform can be generated using commercially available and affordable materials.