Improved Efficacy and Reduced Toxicity Using a Custom-Designed Irinotecan-Delivering Silicasome for Orthotopic Colon Cancer

Development of Facile and Versatile Platinum Drug Delivering Silicasome Nanocarriers for Efficient Pancreatic Cancer Chemo-Immunotherapy

In this study a mesoporous silica nanoparticle (MSNP) based platform is developed for high-dose loading of a range of activated platinum (Pt) chemo agents that can be attached to the porous interior through the use of electrostatic and coordination chemistry under weak-basic pH conditions. In addition to the design feature for improving drug delivery, the MSNP can also be encapsulated in a coated lipid bilayer (silicasome), to improve the colloidal stability after intravenous (IV) injection. Improved pharmacokinetics and intratumor delivery of encapsulated activated oxaliplatin (1,2-diamminocyclohexane platinum(II) (DACHPt)) over free drug in an orthotopic Kras-derived pancreatic cancer (PDAC) model is demonstrated. Not only does IV injection of the DACHPt silicasome provide more efficacious cytotoxic tumor cell killing, but can also demonstrate that chemotherapy-induced cell death is accompanied by the features of immunogenic cell death (ICD) as well as a dramatic reduction in bone marrow toxicity. The added ICD features are reflected by calreticulin and high-mobility group box 1 expression, along with increased CD8+ /FoxP3+ T-cell ratios and evidence of perforin and granzyme B release at the tumor site. Subsequent performance of a survival experiment, demonstrates that the DACHPt silicasome generates a significant improvement in survival outcome, which can be extended by delayed administration of the anti-PD-1 antibody.

Cisplatin Loaded Poly(L-glutamic acid)-g-Methoxy Polyethylene Glycol Complex Nanoparticles Combined with Gemcitabine Presents Improved Safety and Lasting Anti-Tumor Efficacy in a Murine Xenograft Model of Human Aggressive B Cell Lymphoma

Cisplatin (CDDP) is a highly effective anti-tumor drug with a broad spectrum of activity. However, the clinical efficacy of CDDP-containing regimens is yet unsatisfactory due to the severe dose-related toxicity of CDDP. In a previous study, CDDP nanoparticles (L-CDDP) forms a complex as CDDP with poly(L-glutamic acid)-g-methoxy poly(ethylene glycol) with improved safety compared to CDDP. Herein, a murine xenograft model of human aggressive B cell lymphoma (BCL) was established to explore anti-lymphoma efficiency of L-CDDP combined with GEM. BJAB cells represent an aggressive BCL, which were utilized to explore the anti-proliferative effect, cell apoptosis via CCK-8 test and flow cytometry technology, respectively. Toxicity experiment and the maximum tolerated dose (MTD) test were conducted in Kunming mice. Tumor inhibition experiment was conducted at the dose of MTD in SCID beige mice-bearing lymphoma. In this study, the loading capacity and encapsulating efficiency of CDDP in the L-CDDP was 18.3% and 89.7%, respectively, and the hydrodynamic diameter of the prepared L-CDDP was 20.6 nm. The CCK-8 data indicated that the anti-proliferative activity of monodrug groups (GEM, CDDP, L-CDDP) was dose- and time-dependent in BJAB cells. The synergistic effects in anti-lymphoma were detected in these two groups (GEM+CDDP, GEM + L-CDDP). Compared to control group, the proportion of apoptotic cells in experimental groups in BJAB cells was significantly higher at 48 h. Toxicity assays revealed that GEM + L-CDDP regimen had low hematological toxicity, hepatotoxicity, and nephrotoxicity. Tumor inhibition experiment demonstrated that GEM + L-CDDP group exhibited significant tumor-suppressing effects. Moreover, tumors continued to shrink in GEM + L-CDDP group, while these appeared to grow in the GEM + CDDP group. Finally, tumor necrosis was most prominent in the GEM + CDDP and GEM + L-CDDP groups, as assessed by hematoxylin-eosin staining. In conclusion, compared to CDDP, L-CDDP combined with GEM seriously induces BJAB cell apoptosis. Also, GEM + L-CDDP exhibits low hematotoxicity, hepatotoxicity, and nephrotoxicity. Importantly, GEM + L-CDDP presents lasting anti-lymphoma efficacy in a SCID beige mice-bearing lymphoma.

pH-Responsive Release of Ruthenium Metallotherapeutics from Mesoporous Silica-Based Nanocarriers

Ruthenium complexes are attracting interest in cancer treatment due to their potent cytotoxic activity. However, as their high toxicity may also affect healthy tissues, efficient and selective drug delivery systems to tumour tissues are needed. Our study focuses on the construction of such drug delivery systems for the delivery of cytotoxic Ru(II) complexes upon exposure to a weakly acidic environment of tumours. As nanocarriers, mesoporous silica nanoparticles (MSN) are utilized, whose surface is functionalized with two types of ligands, (2-thienylmethyl)hydrazine hydrochloride (H1) and (5,6-dimethylthieno[2,3-d]pyrimidin-4-yl)hydrazine (H2), which were attached to MSN through a pH-responsive hydrazone linkage. Further coordination to ruthenium(II) center yielded two types of nanomaterials MSN-H1[Ru] and MSN-H2[Ru]. Spectrophotometric measurements of the drug release kinetics at different pH (5.0, 6.0 and 7.4) confirm the enhanced release of Ru(II) complexes at lower pH values, which is further supported by inductively coupled plasma optical emission spectrometry (ICP-OES) measurements. Furthermore, the cytotoxicity effect of the released metallotherapeutics is evaluated in vitro on metastatic B16F1 melanoma cells and enhanced cancer cell-killing efficacy is demonstrated upon exposure of the nanomaterials to weakly acidic conditions. The obtained results showcase the promising capabilities of the designed MSN nanocarriers for the pH-responsive delivery of metallotherapeutics and targeted treatment of cancer.

Stimuli-responsive nanocarriers for therapeutic applications in cancer

Cancer has become a very serious challenge with aging of the human population. Advances in nanotechnology have provided new perspectives in the treatment of cancer. Through the combination of nanotechnology and therapeutics, nanomedicine has been successfully used to treat cancer in recent years. In terms of nanomedicine, nanocarriers play a key role in delivering therapeutic agents, reducing severe side effects, simplifying the administration scheme, and improving therapeutic efficacies. Modulations of the structure and function of nanocarriers for improved therapeutic efficacy in cancer have attracted increasing attention in recent years. Stimuli-responsive nanocarriers penetrate deeply into tissues and respond to external or internal stimuli by releasing the therapeutic agent for cancer therapy. Notably, stimuli-responsive nanocarriers reduce the severe side effects of therapeutic agents, when compared with systemic chemotherapy, and achieve controlled drug release at tumor sites. Therefore, the development of stimuli-responsive nanocarriers plays a crucial role in drug delivery for cancer therapy. This article focuses on the development of nanomaterials with stimuli-responsive properties for use as nanocarriers, in the last few decades. These nanocarriers are more effective at delivering the therapeutic agent under the control of external or internal stimuli. Furthermore, nanocarriers with theranostic features have been designed and fabricated to confirm their great potential in achieving effective treatment of cancer, which will provide us with better choices for cancer therapy.

Cyclophosphamide loaded thermo-responsive hydrogel system synergize with a hydrogel cancer vaccine to amplify cancer immunotherapy in a prime-boost manner

Although neoantigen-based cancer vaccines show great potential in cancer immunotherapy due to their ability to induce effective and long-lasting anti-tumor immunity, their development is hindered by the limitations of neoantigens identification, low immunogenicity, and weak immune response. Cyclophosphamide (CTX) not only directly kills tumors but also causes immunogenic cell death, providing a promising source of antigens for cancer vaccines. Herein, a combined immunotherapy strategy based on temperature-sensitive PLEL hydrogel is designed. First, CTX-loaded hydrogel is injected intratumorally into CT26 bearing mice to prime anti-tumor immunity, and then 3 days later, PLEL hydrogels loaded with CpG and tumor lysates are subcutaneously injected into both groins to further promote anti-tumor immune responses. The results confirm that this combined strategy reduces the toxicity of CTX, and produces the cytotoxic T lymphocyte response to effectively inhibit tumor growth, prolong survival, and significantly improve the tumor cure rate. Moreover, a long-lasting immune memory response is observed in the mice. About 90% of the cured mice survive for at least 60 days after being re-inoculated with tumors, and the distant tumor growth is also well inhibited. Hence, this PLEL-based combination therapy may provide a promising reference for the clinical promotion of chemotherapy combined with cancer vaccines.

•

PLEL based-CTX hydrogel system avoided the rapid clearance of CTX and reduced systemic toxicity.

•

PLEL-assisted tumor lysate vaccine was cheap, safe, and contained all tumor antigens.

•

This strategy promoted the maturation and activation of DCs, enhanced cancer-specific CD8⁺ T cell responses.

•

PLEL-assisted combination strategy achieved a good tumor inhibition effect and generate a lasting immune memory. .

•

This local administration strategy could kill tumors that could not be detected or removed surgically in the clinic.

Combination Chemo-Immunotherapy for Pancreatic Cancer Using the Immunogenic Effects of an Irinotecan Silicasome Nanocarrier Plus Anti-PD-1

There is an urgent need to develop new life-prolonging therapy for pancreatic ductal adenocarcinoma (PDAC). It is demonstrated that improved irinotecan delivery by a lipid bilayer coated mesoporous silica nanoparticle, also known as a silicasome, can improve PDAC survival through a chemo-immunotherapy response in an orthotopic Kras-dependent pancreatic cancer model. This discovery is premised on the weak-basic properties of irinotecan, which neutralizes the acidic lysosomal pH in PDAC cells. This effect triggers a linked downstream cascade of events that include autophagy inhibition, endoplasmic reticulum stress, immunogenic cell death (ICD), and programmed death-ligand 1 (PD-L1) expression. ICD is characterized by calreticulin expression and high-mobility group box 1 (HMGB1) release in dying Kras-induced pancreatic cancer (KPC) cells, which is demonstrated in a vaccination experiment to prevent KPC tumor growth on the contralateral site. The improved delivery of irinotecan by the silicasome is accompanied by robust antitumor immunity, which can be synergistically enhanced by anti-PD-1 in the orthotopic model. Immunophenotyping confirms the expression of calreticulin, HMGB1, PD-L1, and an autophagy marker, in addition to perforin and granzyme B deposition. The chemo-immunotherapy response elicited by the silicasome is more robust than free or a liposomal drug, Onivyde. The silicasome plus anti-PD-1 leads to significantly enhanced survival improvement, and is far superior to anti-PD-1 plus either free irinotecan or Onivyde.

Immune checkpoint inhibition in syngeneic mouse cancer models by a silicasome nanocarrier delivering a GSK3 inhibitor

Checkpoint blocking antibodies that interfere in the PD-1/PD-L1 axis provide effective cancer immunotherapy for tumors that are immune inflamed or induced to become "hot". It has also been demonstrated that a small molecule inhibitor of the signaling hub kinase GSK3 can interfere in the PD-1/PD-L1 axis in T-cells by suppressing PD-1 expression. This provides an alternative approach to intervening in the PD-1/PD-L1 axis to provide cancer immunotherapy. In this communication, we demonstrate the remote loading of GSK3 inhibitor AZD1080 into the porous interior of mesoporous silica nanoparticles coated with a lipid bilayer (a.k.a. silicasomes). In a MC38 colon cancer model, intravenous injection (IV) of silicasome-encapsulated AZD1080 significantly improved biodistribution and drug delivery to the tumor site. The improved drug delivery was accompanied by cytotoxic MC38 tumor cell killing by perforin-releasing CD8⁺ T-cells, exhibiting reduced PD-1 expression. IV injection of encapsulated AZD1080 also resulted in significant tumor shrinkage in other syngeneic mouse tumor models, including another colorectal tumor (CT26), as well as pancreas (KPC) and lung (LLC) cancer models. Not only was the therapeutic efficacy of encapsulated AZD1080 similar or better than anti-PD-1 antibody, but the treatment was devoid of treatment toxicity. These results provide proof-of-principal demonstration of the feasibility of using encapsulated delivery of a GSK3 inhibitor to provide cancer immunotherapy, with the possibility to be used as a monotherapy or in combination with chemotherapy or other immunomodulatory agents.

The emerging landscape of nanotheranostic-based diagnosis and therapy for osteoarthritis

Osteoarthritis (OA) is a common degenerative disease involving numerous joint tissues and cells, with a growing rate in prevalence that ultimately results in a negative social impact. Early diagnosis, OA progression monitoring and effective treatment are of significant importance in halting OA process. However, traditional imaging techniques lack sensitivity and specificity, which lead to a delay in timely clinical intervention. Additionally, current treatments only slow the progression of OA but have not meet the largely medical need for disease-modifying therapy. In order to overcome the above-mentioned problems and improve clinical efficacy, nanotheranostics has been proposed on OA remedy, which has confirmed success in animal models. In this review, different imaging targets-based nanoprobe for early and timely OA diagnosis is first discussed. Second, therapeutic strategies delivered by nanosystem are summarized as much as possible. Their advantages and the potential for clinical translation are detailed discussed. Third, nanomedicine simultaneously combined with the imaging for OA treatment is introduced. Nanotheranostics dynamically tracked the OA treatment outcomes to timely and individually adjust therapy. Finally, future prospects and challenges of nanotechnology-based OA diagnosis, imaging and treatment are concluded and predicted. It is believed that nanoprobe and nanomedicine will become prospective in OA therapeutic revolution.

Mesoporous silica nanoparticles: facile surface functionalization and versatile biomedical applications in oncology

Mesoporous silica nanoparticles (MSNs) have received increasing interest due to their tunable particle size, large surface area, stable framework, and easy surface modification. They are increasingly being used in varying applications as delivery vehicles including bio-imaging, drug delivery, biosensors and tissue engineering etc. Precise structure control and the ability to modify surface properties of MSNs are important for their applications. This review summarises the different synthetic methods for the preparation of well-ordered MSNs with tunable pore volume as well as the approaches of drugs loading, especially highlighting the facile surface functionalization for various purposes and versatile biomedical applications in oncology. Finally, the challenges of clinical transformation of MSNs-based nanomedicines are further discussed.

Safety Considerations of Cancer Nanomedicine-A Key Step toward Translation

The rate of translational effort of nanomedicine requires strategic planning of nanosafety research in order to enable clinical trials and safe use of nanomedicine in patients. Herein, the experiences that have emerged based on the safety data of classic liposomal formulations in the space of oncology are discussed, along with a description of the new challenges that need to be addressed according to the rapid expansion of nanomedicine platform beyond liposomes. It is valuable to consider the combined use of predictive toxicological assessment supported by deliberate investigation on aspects such as absorption, distribution, metabolism, and excretion (ADME) and toxicokinetic profiles, the risk that may be introduced during nanomanufacture, unique nanomaterials properties, and nonobvious nanosafety endpoints, for example. These efforts will allow the generation of investigational new drug-enabling safety data that can be incorporated into a rational infrastructure for regulatory decision-making. Since the safety assessment relates to nanomaterials, the investigation should cover the important physicochemical properties of the material that may lead to hazards when the nanomedicine product is utilized in humans.

Use of ratiometrically designed nanocarrier targeting CDK4/6 and autophagy pathways for effective pancreatic cancer treatment

Aberrant cell cycle machinery and loss of the CDKN2A tumor suppressor locus make CDK4/6 a potential target in pancreatic ductal adenocarcinoma (PDAC). However, a vast majority of PDAC cases do not harbor a durable response to monotherapy of CDK4/6 inhibitor. Utilizing remote loading to co-encapsulate CDK4/6 inhibitor palbociclib (PAL) and an autophagy inhibitor hydroxychloroquine (HCQ), we demonstrate a ratiometrically designed mesoporous silica nanoformulation with synergistic efficacy in subcutaneous and orthotopic PDAC mouse models. The synergism is attributed to the effective intratumoral buildup of PAL/HCQ, which otherwise exhibit distinctly different circulatory and biodistribution profile. PAL/HCQ co-delivery nanoparticles lead to the most effective shrinkage of PDAC compared to various controls, including free drug mixture. Immunohistochemistry reveals that PAL/HCQ co-delivery nanoparticles trigger anti-apoptotic pathway after repetitive intravenous administrations in mice. When combined with a Bcl inhibitor, the performance of co-delivery nanoparticles is further improved, leading to a long-lasting anti-PDAC effect in vivo.

Aberrant cell cycle machinery and loss of the CDKN2A tumor suppressor locus make CDK4/6 a potential target in pancreatic ductal adenocarcinoma (PDAC). Here, the authors use ratiometrically designed nanoparticles to codeliver the CDK4/6 inhibitor palbociclib and the autophagy inhibitor hydroxychloroquine, and show their synergistic therapeutic effects in mouse model of PDAC.

Colon-specific immune microenvironment regulates cancer progression versus rejection

Immunotherapies have achieved clinical benefit in many types of cancer but remain limited to a subset of patients in colorectal cancer (CRC). Resistance to immunotherapy can be attributed in part to tissue-specific factors constraining antitumor immunity. Thus, a better understanding of how the colon microenvironment shapes the immune response to CRC is needed to identify mechanisms of resistance to immunotherapies and guide the development of novel therapeutics. In an orthotopic mouse model of MC38-CRC, tumor progression was monitored by bioluminescence imaging and the immune signatures were assessed at a transcriptional level using NanoString and at a cellular level by flow cytometry. Despite initial tumor growth in all mice, only 25% to 35% of mice developed a progressive lethal CRC while the remaining animals spontaneously rejected their solid tumor. No tumor rejection was observed in the absence of adaptive immunity, nor when MC38 cells were injected in non-orthotopic locations, subcutaneously or into the liver. We observed that progressive CRC tumors exhibited a protumor immune response, characterized by a regulatory T-lymphocyte pattern, discernible shortly post-tumor implantation, as well as suppressive myeloid cells. In contrast, tumor-rejecting mice presented an early inflammatory response and an antitumor microenvironment enriched in CD8⁺ T cells. Taken together, our data demonstrate the role of the colon microenvironment in regulating the balance between anti or protumor immune responses. While emphasizing the relevance of the CRC orthotopic model, they set the basis for exploring the impact of the identified signatures in colon cancer response to immunotherapy.

Scoulerine promotes cell viability reduction and apoptosis by activating ROS-dependent endoplasmic reticulum stress in colorectal cancer cells

Scoulerine, an isoquinoline alkaloid isolated from Corydalis plants, has been reported to possess potent anti-proliferative and pro-apoptotic function in cancer cells. However, the effects and underlying mechanisms of scoulerine on colorectal cancer (CRC) progression remain elusive. CCK-8 and LDH assays were used to evaluate cell viability. Apoptosis was assessed by flow cytometry analysis, caspase-3/7 activity assay, and Western blot analysis of Bax, Bcl-2 and cytochrome c (Cyt C) expression. Oxidative stress level was examined by measuring reactive oxygen species (ROS) and glutathione (GSH) contents and superoxide dismutase (SOD) activity. Endoplasmic reticulum (ER) stress activation was detected by Western blot analysis of glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP) expression. Results showed that scoulerine dose-dependently suppressed CRC cell viability. Scoulerine induced apoptosis and increased caspase-3/7 activity in CRC cells. Bax and cytosolic Cyt C expression was enhanced while Bcl-2 and mitochondrial Cyt C expression was reduced in scoulerine-treated CRC cells. Additionally, scoulerine induced oxidative damage in CRC cells by increasing ROS generation and reducing GSH content and SOD activity. Scoulerine activated ER stress, as evidenced by the increased GRP78 and CHOP expression in CRC cells. Interestingly, blocking ROS production by ROS scavenger N-acetyl-cysteine (NAC) attenuated scoulerine-induced ER stress. Inhibition of ER stress by 4-phenyl butyric acid (4-PBA) abolished scoulerine-induced ROS generation in CRC cells. Blockage of ROS and ER stress attenuated scoulerine-induced cell viability reduction and apoptosis in CRC cells. In conclusion, scoulerine promoted cell viability reduction and apoptosis by activating ROS-dependent ER stress in CRC cells.

Controllable synthesis of versatile mesoporous organosilica nanoparticles as precision cancer theranostics

Despite the advantages of mesoporous silica nanoparticles (MSNs) in drug delivery, the inherent non-biodegradability seriously impedes the clinical translation of inorganic MSNs, so the current research focus has been turned to mesoporous organosilica nanoparticles (MONs) with higher biocompatibility and easier biodegradability. Recent remarkable advances in silica fabrication chemistry have catalyzed the emergence of a library of MONs with various structures and functions. This review will summarize the latest state-of-the-art studies on the precise control of morphology, structure, framework, particle size and pore size of MONs, which enables the precise synthesis of MONs with suitable engineering for precision stimuli-responsive drug delivery/release, bioimaging and synergistic therapy. Besides, the potential challenges about the future development of MONs are also outlooked with the intention of attracting more researchers to promote the clinical translation of MONs.

Nanobowl-Supported Liposomes Improve Drug Loading and Delivery

Liposomal drug delivery for cancer therapy can be limited due to drug leakage in circulation. Here, we develop a new method to enhance the stability of actively loaded liposomal doxorubicin (DOX) through embedding a stiff nanobowl in the liposomal water cavity. Nanobowl-supported liposomal DOX (DOX@NbLipo) resists the influence of plasma protein and blood flow shear force to prevent drug leakage. This approach yields improved drug delivery to tumor sites and enhanced antitumor efficacy. Compared to alternative methods of modifying liposome surface and composition for stability, this approach designs a physical support for an all-aqueous nanoliposomal cavity. Nanobowl stabilization of liposomes is a simple and effective method to improve carrier stability and drug delivery.

RhB-encapsulating silica nanoparticles modified with PEG impact the vascular endothelial function in endothelial cells and zebrafish model

Silica nanoparticles (SiNPs) have been widely used in human health related products, such as food additives, cosmetics and even drug delivery, gene therapy or bioimaging. Recently, a first-in-human clinical trial based on polyethylene glycol (PEG)-modified SiNPs had been approved by US FDA to trace melanoma. However, as a nano-based drug delivery system, its biocompatibility and vascular toxicity are still largely unknown. Thus, we synthesized the fluorescent SiNPs to explore the biocompatibility and vascular endothelial function, and compare different biological effects caused by PEG-modified and unmodified SiNPs in cells and zebrafish model. The characterizations of SiNPs and PEG-modified SiNPs were analyzed by TEM, SEM, AFM and DLS, which exhibited relatively good stable and dispersive. Compared with SiNPs, PEG-modified SiNPs had markedly reduced the inflammatory response and vascular damage in Tg (fli-1: EGFP) and Tg (mpo: GFP) transgenic zebrafish lines, respectively. Consistent with the in vivo results, the PEG-modified SiNPs had been found to significantly decline the levels of ROS, inflammatory cytokines and mitochondrial-mediated apoptosis in vascular endothelial cells compared to SiNPs, and the ROS scavenger NAC could effectively alleviate the above adverse effects induced by nanoparticles. Our results suggested that the PEG-modified SiNPs could become more safety via increasing the biocompatibility and decreasing cellular toxicities in living organisms.

Localized cocktail chemoimmunotherapy after in situ gelation to trigger robust systemic antitumor immune responses

Currently, there is a huge demand to develop chemoimmunotherapy with reduced systemic toxicity and potent efficacy to combat late-stage cancers with spreading metastases. Here, we report several "cocktail" therapeutic formulations by mixing immunogenic cell death (ICD)-inducing chemotherapeutics and immune adjuvants together with alginate (ALG) for localized chemoimmunotherapy. Immune checkpoint blockade (ICB) antibody may be either included into this cocktail for local injection or used via conventional intravenous injection. After injection of such cocktail into a solid tumor, in-situ gelation of ALG would lead to local retention and sustained release of therapeutics to reduce systemic toxicity. The chemotherapy-induced ICD with the help of immune adjuvant would trigger tumor-specific immune responses, which are further amplified by ICB to elicit potent systemic antitumor immune responses in destructing local tumors, eliminating metastases and inhibiting cancer recurrence. Our strategy of combining clinically used agents for tumor-localized cocktail chemoimmunotherapy possesses great potential for clinical translation.

LYW-6, a novel cryptotanshinone derived STAT3 targeting inhibitor, suppresses colorectal cancer growth and metastasis

The constitutive activation of signal transducer and activator of transcription 3(STAT3) is associated with aggressive development and metastasis in colorectal cancer (CRC), but STAT3-targeting drugs remain elusive in clinic. Here, structure-based strategy was used to remodel the natural compound cryptotanshinone into a more effective STAT3 inhibitor LYW-6. Using the Biolayer Interferometry assay, we observed that LYW-6 exhibited specific interactions with STAT3(KD = 6.6 ± 0.7 μM). Western blot analysis and electrophoretic mobility shift assays (EMSA) showed that LYW-6 inhibited the phosphorylation of STAT3 tyrosine 705 (Tyr-705) and had slight effects on STAT1 and STAT5 phosphorylation. Western blot analysis on the upstream kinases of STAT3 confirmed that the inhibitory mechanism on p-STAT3 was independent of upstream kinases. Further investigation demonstrated that LYW-6 downregulated the expression of downstream oncogenes to inhibit cell viability, cell cycle development, and potently increased cell apoptosis in human CRC cells. The invasion and metastasis linked signaling was also blocked by LYW-6 treatment. LYW-6 was found to reduce the metastasis foci in lung on tail-lung metastasis models. In addition, it was observed that LYW-6 markedly diminished STAT3 phosphorylation in tumor tissue and significantly inhibited tumor growth on xenograft models. Tumor development on chemically-induced colorectal cancer model also significantly inhibited by LYW-6 treatment. These findings provided adequate evidence that STAT3 inhibitor LYW-6 might be a potential candidate agent for CRC treatment.

Synthesis, mechanisms of action, and toxicity of novel aminophosphonates derivatives conjugated irinotecan in vitro and in vivo as potent antitumor agents

Twenty novel aminophosphonates derivatives (5a-5j and 6a-6j) conjugated irinotecan were synthesized through esterification reaction, and evaluated their anticancer activities using MTT assay. In vitro evaluation revealed that they displayed similar or superior cytotoxicity compared to the positive drug irinotecan against A549, MCF-7, SK-OV-3, MG-63, U2OS and multidrug-resistant (MDR) SK-OV-3/CDDP cancer cell lines. Among them, 9b displayed the most potent activity, with IC₅₀ values of 0.92-3.23 μM against five human cancer cells, which exhibited a 5.4-19.1-fold increase in activity compared to the reference drug irinotecan, respectively. Moreover, cellular mechanism studies suggested that 9b arrested cell cycle at S stage and induced cell apoptosis along with the decrease of mitochondrial membrane potential (MMP). Interestingly, 9b significantly inhibited tumor growth in SK-OV-3 xenograft models in vivo without apparent toxicity, which was better than the positive drug irinotecan. Taken together, 9b possessed potent antitumor activity and may be a promising candidate for the potential treatment of human ovarian cancer cells.

Biodegradable Mesoporous Silica Achieved via Carbon Nanodots-Incorporated Framework Swelling for Debris-Mediated Photothermal Synergistic Immunotherapy

Incorporating carbon nanodots (CDs) into mesoporous silica framework for extensive biomedicine, especially for the desirable cancer immunotherapy, is considered to be an unexplored challenge. Herein, a hydrogen bond/electrostatic-assisted co-assembly strategy was smartly exploited to uniformly incorporate polymer-coated CDs into ordered framework of mesoporous silica nanoparticles (CD@MSNs). The obtained CD@MSN was not only biodegradable via the framework-incorporated CD-induced swelling but also capable of gathering dispersive CDs with enhanced photothermal effect and elevated targeting accumulation, which therefore can achieve photothermal imaging-guided photothermal therapy (PTT) in vitro and in vivo. Interestingly, benefiting from the biodegraded debris, it was found that CD@MSN-mediated PTT can synergistically achieve immune-mediated inhibition of tumor metastasis via stimulating the proliferation and activation of natural killer cells and macrophages with simultaneously up-regulating the secretion of corresponding cytokines (IFN-γ and Granzyme B). This work proposed an unusual synthesis of biodegradable mesoporous silica and provided an innovative insight into the biodegradable nanoparticles-associated anticancer immunity.

Bacterial Biofilm Bioinspired Persistent Luminescence Nanoparticles with Gut-Oriented Drug Delivery for Colorectal Cancer Imaging and Chemotherapy

Colorectal cancer (CRC) is now one of the leading causes of cancer incidence and mortality. Although nanomaterial-based drug delivery has been used for the treatment of colorectal cancer, inferior targeting ability of existing nanocarriers leads to inefficient treatment and side effects. Moreover, the majority of intravenously administered nanomaterials aggregate into the reticuloendothelial system, leaving a certain hidden risk to human health. All those problems gave great demands for further construction of well-performed and biocompatible nanomaterials for in vivo theranostics. In the present work, from a biomimetic point of view, Lactobacillus reuteri biofilm (LRM) was coated on the surface of trackable zinc gallogermanate (ZGGO) near-infrared persistent luminescence mesoporous silica to create the bacteria bioinspired nanoparticles (ZGGO@SiO₂@LRM), which hold the inherent capability of withstanding the digestion of gastric acid and targeted release 5-FU to colorectum. Through the background-free persistent luminescence bioimaging of ZGGO, the coating of LRM facilitated the localization of ZGGO@SiO₂@LRM to the tumor area of colorectum for more than 24 h after intragastric administration. Furthermore, ZGGO@SiO₂@LRM hardly entered the blood, which avoided possible damage to immune organs such as the liver and spleen. In vivo chemotherapy experiment demonstrated the number of tumors per mouse in ZGGO@SiO₂@LRM group decreased by one-half compared with the 5-FU group (P < 0.001). To sum up, this LRM bioinspired nanoparticles could tolerate the digestion of gastric acid, avoid aggregation by the immune system, favor gut-oriented drug delivery, and targeted release oral 5-FU into colorectum for more than 24 h, which may give new application prospects for targeted delivery of oral drugs into the colorectum.

Hierarchically Nanostructured Hybrid Platform for Tumor Delineation and Image-Guided Surgery via NIR-II Fluorescence and PET Bimodal Imaging

Bimodal imaging with fluorescence in the second near infrared window (NIR-II) and positron emission tomography (PET) has important significance for tumor diagnosis and management because of complementary advantages. It remains challenging to develop NIR-II/PET bimodal probes with high fluorescent brightness. Herein, bioinspired nanomaterials (melanin dot, mesoporous silica nanoparticle, and supported lipid bilayer), NIR-II dye CH-4T, and PET radionuclide ⁶⁴ Cu are integrated into a hybrid NIR-II/PET bimodal nanoprobe. The resultant nanoprobe exhibits attractive properties such as highly uniform tunable size, effective payload encapsulation, high stability, dispersibility, and biocompatibility. Interestingly, the incorporation of CH-4T into the nanoparticle leads to 4.27-fold fluorescence enhancement, resulting in brighter NIR-II imaging for phantoms in vitro and in situ. Benefiting from the fluorescence enhancement, NIR-II imaging with the nanoprobe is carried out to precisely delineate and resect tumors. Additionally, the nanoprobe is successfully applied in tumor PET imaging, showing the accumulation of the nanoprobe in a tumor with a clear contrast from 2 to 24 h postinjection. Overall, this hierarchically nanostructured platform is able to dramatically enhance fluorescent brightness of NIR-II dye, detect tumors with NIR-II/PET imaging, and guide intraoperative resection. The NIR-II/PET bimodal nanoprobe has high potential for sensitive preoperative tumor diagnosis and precise intraoperative image-guided surgery.

Irinotecan: 25 years of cancer treatment

Twenty-five years ago, the cytotoxic drug irinotecan (IRT) was first approved in Japan for the treatment of cancer. For more than two decades, the IRT prodrug has largely contributed to the treatment of solid tumors worldwide. Nowadays, this camptothecin derivative targeting topoisomerase 1 remains largely used in combination regimen, like FOLFIRI and FOLFIRINOX, to treat metastatic or advanced solid tumors, such as colon, gastric and pancreatic cancers and others. This review highlights recent discoveries in the field of IRT and its derivatives, including analogues of the active metabolite SN38 (such as FL118), the recently approved liposomal form Nal-IRI and SN38-based immuno-conjugates currently in development (such as sacituzumab govitecan). New information about the IRT mechanism of action are presented, including the discovery of a new protein target, the single-stranded DNA-binding protein FUBP1. Significant progress has been made also to better understand and manage the main limiting toxicities of IRT, chiefly neutropenia and diarrhea. The role of drug-induced inflammation and dysbiosis is underlined and strategies to limit the intestinal toxicity of IRT are discussed (use of β-glucuronidase inhibitors, plant extracts, probiotics). The detailed knowledge of the metabolism of IRT has enabled the identification of potential biomarkers to guide patient selection and to limit drug-induced toxicities, but no robust IRT-specific therapeutic biomarker has been approved yet. IRT is a versatile chemotherapeutic agent which combines well with a variety of anticancer drugs. It offers a large range of drug combinations with cytotoxic agents, targeted products and immuno-active biotherapeutics, to treat a variety of advanced solid carcinoma, sarcoma and cancers with progressive central nervous system diseases. A quarter of century after its first launch, IRT remains an essential anticancer drug, largely prescribed, useful to many patients and scientifically inspiring.