Tumor Penetration Research Articles

Inhibition of iRhom1 by CD44-targeting nanocarrier for improved cancer immunochemotherapy

The multifaceted chemo-immune resistance is the principal barrier to achieving cure in cancer patients. Identifying a target that is critically involved in chemo-immune-resistance represents an attractive strategy to improve cancer treatment. iRhom1 plays a role in cancer cell proliferation and its expression is negatively correlated with immune cell infiltration. Here we show that iRhom1 decreases chemotherapy sensitivity by regulating the MAPK14-HSP27 axis. In addition, iRhom1 inhibits the cytotoxic T-cell response by reducing the stability of ERAP1 protein and the ERAP1-mediated antigen processing and presentation. To facilitate the therapeutic translation of these findings, we develop a biodegradable nanocarrier that is effective in codelivery of iRhom pre-siRNA (pre-siiRhom) and chemotherapeutic drugs. This nanocarrier is effective in tumor targeting and penetration through both enhanced permeability and retention effect and CD44-mediated transcytosis in tumor endothelial cells as well as tumor cells. Inhibition of iRhom1 further facilitates tumor targeting and uptake through inhibition of CD44 cleavage. Co-delivery of pre-siiRhom and a chemotherapy agent leads to enhanced antitumor efficacy and activated tumor immune microenvironment in multiple cancer models in female mice. Targeting iRhom1 together with chemotherapy could represent a strategy to overcome chemo-immune resistance in cancer treatment.

Enhancing the tumor penetration of multiarm polymers by collagenase modification.

Tumor penetration is a critical determinant of the therapy efficacy of nanomedicines. However, the dense extracellular matrix (ECM) in tumors significantly hampers the deep penetration of nanomedicines, resulting in large drug-untouchable areas and unsatisfactory therapy efficacy. Herein, we synthesized a third-generation PAMAM-cored multiarm copolymer and modified the polymer with collagenase to enhance its tumor penetration. Each arm of the copolymer was a diblock copolymer of poly(glutamic acid)-b-poly(carboxybetaine), in which the polyglutamic acid block with abundant side groups was used to link the anticancer agent doxorubicin through the pH-sensitive acylhydrazone linkage, and the zwitterionic poly(carboxybetaine) block provided desired water solubility and anti-biofouling capability. The collagenase was conjugated to the ends of the arms via the thiol-maleimide reaction. We demonstrated that the polymer-bound collagenase could effectively catalyze the degradation of the collagen in the tumor ECM, and consequently augmented the tumor penetration and antitumor efficacy of the drug-loaded polymers.

Enhanced urease-driven nanobots for radionuclide-based bladder cancer therapy

Bladder cancer treatment with intravenous medication delivery has reasonable survival rates but modest therapeutic efficacy. Taking advantage of their superior diffusion and mixing capacities in urine compared to traditional pharmaceuticals or passive nanoparticles, self-propelled nanoparticles, also known as nanobots, have been proposed as a solution to the latter issue. Nonetheless, nothing is known about how well nanobots can translate into bladder cancer treatments. Here, urease-powered, radiolabelled mesoporous silica-based nanobots were evaluated in an orthotopic animal model of bladder cancer. Both in vivo and ex vivo findings showed increased accumulation of nanobots at the tumor location; positron emission tomography in vivo showed an eight-fold increase. The ex vivo tumor penetration by nanobots was validated by label-free optical contrast based on polarization-dependent scattered light-sheet microscopy of cleared bladders. Intravesically treatment was given to tumor-bearing mice. About 90% less tumor size was observed when radio-iodinated nanobots were used for radionuclide therapy, establishing nanobots as effective delivery nanosystems for bladder cancer treatment.

Combined Photothermal Chemotherapy for Effective Treatment Against Breast Cancer in Mice Model.

Breast cancer ranks among the most prevalent cancers in women, characterized by significant morbidity, disability, and mortality. Presently, chemotherapy is the principal clinical approach for treating breast cancer; however, it is constrained by limited targeting capability and an inadequate therapeutic index. Photothermal therapy, as a non-invasive approach, offers the potential to be combined with chemotherapy to improve tumor cellular uptake and tissue penetration. In this research, a mesoporous polydopamine-coated gold nanorod nanoplatform, encapsulating doxorubicin (Au@mPDA@DOX), was developed. This nanoplatform was constructed by surface coating mesoporous polydopamine (mPDA) onto gold nanorods, and doxorubicin (DOX) was encapsulated in Au@mPDA owing to π-π stacking between mPDA and DOX. The dynamic diameter, zeta potential, absorbance, photothermal conversion ability, and drug release behavior were determined. The cellular uptake, cytotoxicity, deep penetration, and anti-tumor effects were subsequently investigated in 4T1 cells. After that, fluorescence imaging, photothermal imaging and pharmacodynamics studies were utilized to evaluate the anti-tumor effects in tumor-bearing mice model. This nanoplatform exhibited high drug loading capacity, excellent photothermal conversion and, importantly, pH/photothermal dual-responsive drug release behavior. The in vitro results revealed enhanced photothermal-facilitated cellular uptake, drug release and tumor penetration of Au@mPDA@DOX under near-infrared irradiation. In vivo studies confirmed that, compared with monotherapy with either chemotherapy or photothermal therapy, the anti-tumor effects of Au@mPDA@DOX are synergistically improved. Together with good biosafety and biocompatibility, the Au@mPDA@DOX nanoplatform provides an alternative method for safe and synergistic treatment of breast cancer.

Tumor immune microenvironment permissive to metastatic progression of ING4-deficient breast cancer.

Deficiencies in the ING4 tumor suppressor are associated with advanced stage tumors and poor patient survival in cancer. ING4 was shown to inhibit NF-kB in several cancers. As NF-kB is a key mediator of immune response, the ING4/NF-kB axis is likely to manifest in tumor-immune modulation but has not been investigated. To characterize the tumor immune microenvironment associated with ING4-deficient tumors, three approaches were employed in this study: First, tissue microarrays composed of 246 primary breast tumors including 97 ING4-deficient tumors were evaluated for the presence of selective immune markers, CD68, CD4, CD8, and PD-1, using immunohistochemical staining. Second, an immune-competent mouse model of ING4-deficient breast cancer was devised utilizing CRISPR-mediated deletion of Ing4 in a Tp53 deletion-derived mammary tumor cell line; mammary tumors were evaluated for immune markers using flow cytometry. Lastly, the METABRIC gene expression dataset was evaluated for patient survival related to the immune markers associated with Ing4-deleted tumors. The results showed that CD68, CD4, CD8, or PD-1, was not significantly associated with ING4-deficient breast tumors, indicating no enrichment of macrophages, T cells, or exhausted T cell types. In mice, Ing4-deleted mammary tumors had a growth rate comparable to Ing4-intact tumors but showed increased tumor penetrance and metastasis. Immune marker analyses of Ing4-deleted tumors revealed a significant increase in tumor-associated macrophages (Gr-1loCD11b+F4/80+) and a decrease in granzyme B-positive (GzmB+) CD4+ T cells, indicating a suppressive and/or less tumoricidal immune microenvironment. The METABRIC data analyses showed that low expression of GZMB was significantly associated with poor patient survival, as was ING4-low expression, in the basal subtype of breast cancer. Patients with GZMB-low/ING4-low tumors had the worst survival outcomes (HR = 2.80, 95% CI 1.36-5.75, p = 0.0004), supportive of the idea that the GZMB-low immune environment contributes to ING4-deficient tumor progression. Collectively, the study results demonstrate that ING4-deficient tumors harbor a microenvironment that contributes to immune evasion and metastasis.

Charge-reversal polymeric nanomodulators for ferroptosis-enhanced photodynamic therapy.

The clinical application of photodynamic therapy (PDT) has some limitations including poor tumor targeting properties, a high reductive tumor microenvironment, and inefficient activation of single cell death machinery. We herein report pH-sensitive polymeric nanomodulators (NBS-PDMC NPs) for ferroptosis-enhanced photodynamic therapy. NBS-PDMC NPs were constructed using a positively charged type-I photosensitizer (NBS) coordinated with a demethylcantharidin (DMC)-decorated block copolymer via electrostatic interactions. NBS-PDMC NPs had a negative surface charge, which ensures their high stability in bloodstream circulation, while exposure to lysosomal acidic environments reverses their surface charge to positive for tumor penetration and the release of DMC and NBS. Under NIR light irradiation, NBS generated ROS to induce cell damage; in the meantime, DMC inhibited the expression of the GPX4 protein in tumor cells and promoted ferroptosis of tumor cells. This polymer design concept provides some novel insights into smart drug delivery and combinational action to amplify the antitumor effect.

N-Sulfonyl amidine polypeptides: new polymeric biomaterials with conformation transition responsive to tumor acidity.

Manipulation of pH responsiveness is a frequently employed tactic in the formulation of trigger-responsive nanomaterials. It offers an avenue for "smart" designs capitalizing on distinctive pH gradients across diverse tissues and intracellular compartments. However, an overwhelming majority of documented functional groups (>80%) exhibit responsiveness solely to the heightened acidic milieu of intracellular pH (about 4.5-5.5). This scenario diverges markedly from the moderately acidic extracellular pH (∼6.8) characteristic of tumor microenvironments. Consequently, systems predicated upon intracellular pH responsiveness are unlikely to confer discernible advantages concerning targeted penetration and cellular uptake at tumor sites. In this study, we elucidated the extracellular pH responsiveness intrinsic to N-sulfonyl amidine (SAi), delineating a method to synthesize an array of SAi-bearing polypeptides (SAi-polypeptides). Notably, we demonstrated the pH-dependent modulation of SAi-polypeptide conformations, made possible by the protonation/deprotonation equilibrium of SAi in response to minute fluctuations in pH from physiological conditions to the extracellular milieu of tumors. This dynamic pH-triggered transition of SAi-polypeptides from negatively charged to neutrally charged side chains at the pH outside tumor cells (∼6.8) facilitated a transition from coil to helix conformations, concomitant with the induction of cellular internalization upon arrival at tumor sites. Furthermore, the progressive acidification of the intracellular environment expedited drug release, culminating in significantly enhanced site-specific chemotherapeutic efficacy compared with free-drug counterparts. The distinct pH-responsive attributes of SAi could aid the design of tumor acidity-responsive applications, thereby furnishing invaluable insights into the realm of smart material design.

MMP-2 Responsive Peptide Hydrogel-Based Nanoplatform for Multimodal Tumor Therapy.

Responsive drug delivery systems hold great promise for tumor treatment as they focus on therapeutic agents directly, thus minimizing systemic toxicities and drug leakage. In this study, we covalently bound a matrix metalloproteinases-2 (MMP-2) enzyme-sensitive peptide to a tissue-penetrating peptide to rationally design a MMP-2 responsive multifunctional peptide hydrogel platform (aP/IR@FMKB) for cancer photothermal-chemo-immunotherapy. The constructed aP/IR@FMKB with bufalin (BF) loaded in trimethyl chitosan nanoparticles (TB NPs), photothermal agent IR820, and immune checkpoint inhibitor aPD-L1 by self-assembly could be dissociated in the presence of MMP-2 enzyme, triggering content release. TB NPs, IR820, and aPD-L1 were encapsulated by intermolecular self-assembly and enzyme-sensitive nanogels (aP/IR@FMKB) were constructed. The in vitro cytotoxicity of the blank gels and their ability to induce immunogenic cell death (ICD) in aP/IR@FMKB were evaluated using 4T1 cells. The promotion of deep tumor penetration and enzyme responsiveness was analyzed using a 3D cell model. The retention and antitumor activity at the tumor sites were examined using the primary tumor model. To assess the antitumor effect of aP/IR@FMKB induced by the immune response and its mechanism of action, recurrent tumor and distal tumor models were constructed. This hydrogel system demonstrated exceptional photothermal performance and displayed prolonged local retention. Furthermore, the induction of ICD through IR820 and TB NPs sensitized the PD-L1 blockade, resulting in a remarkable 3.5-fold and 5.2-fold increase in the frequency of intratumor-infiltrating CD8+ T-cells in the primary tumor and distal tumor, respectively. Additionally, this system demonstrated remarkable efficacy in suppressing primary, distal, and recurrent tumors, underscoring its potential as a highly potent therapeutic strategy. This innovative design of the responsive hydrogel can effectively modulate the tumor immune microenvironment while also demonstrating sensitivity to the PD-1/PD-L1 blockade. This significant finding highlights the promising potential of this hydrogel in the field of multimodal tumor therapy.

Post cross-linked ROS-responsive poly(β-amino ester)-plasmid polyplex NPs for gene therapy of EBV-associated nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is one of the most common tumors in South China and Southeast Asia and is thought to be associated with Epstein-Barr virus (EBV) infection. Downregulation of latent membrane protein 1 (LMP1) encoded by EBV can reduce the expression of NF-κB and PI3K, induce apoptosis, and inhibit the growth of EBV-related NPC. For targeted cleavage of the Lmp1 oncogene via the CRISPR/Cas9 gene editing system, a post cross-linked ROS-responsive poly(β-amino ester) (PBAE) polymeric vector was developed for the delivery of CRISPR/Cas9 plasmids both in vitro and in vivo. After composition optimization, the resultant polymer-plasmid polyplex nanoparticles (NPs) showed a diameter of ∼230 nm and a zeta potential of 22.3 mV with good stability. Compared with the non-cross-linked system, the cross-linked NPs exhibited efficient and quick cell uptake, higher transfection efficiency in EBV-positive C666-1 cells (53.5% vs. 40.6%), more efficient gene editing ability against the Mucin2 model gene (Muc2) (17.9% vs. 15.4%) and Lmp1 (8.5% vs. 5.6%), and lower intracellular reactive oxygen species (ROS) levels. The NPs achieved good tumor penetration and tumor growth inhibition in the C666-1 xenograft tumor model via Lmp1 cleavage, indicating their potential for gene therapy of EBV-related NPC.

AGuIX nanoparticle-nanobody bioconjugates to target immune checkpoint receptors.

This article presents bioconjugates combining nanoparticles (AGuIX) with nanobodies (VHH) targeting Programmed Death-Ligand 1 (PD-L1, A12 VHH) and Cluster of Differentiation 47 (CD47, A4 VHH) for active tumor targeting. AGuIX nanoparticles offer theranostic capabilities and an efficient biodistribution/pharmacokinetic profile (BD/PK), while VHH's reduced size (15 kDa) allows efficient tumor penetration. Site-selective sortagging and click chemistry were compared for bioconjugation. While both methods yielded bioconjugates with similar functionality, click chemistry demonstrated higher yield and could be used for the conjugation of various VHH. The specific targeting of AGuIX@VHH has been demonstrated in both in vitro and ex vivo settings, paving the way for combined targeted immunotherapies, radiotherapy, and cancer imaging.

Cascade-responsive size/charge bidirectional-tunable nanodelivery penetrates pancreatic tumor barriers.

The pancreatic tumor microenvironment presents multiple obstacles for polymer-based drug delivery systems, limiting tumor penetration and treatment efficacy. Here, we engineer a hyaluronidase/reactive oxygen species cascade-responsive size/charge bidirectional-tunable nanodelivery (btND, G/R@TKP/HA) for co-delivery of gemcitabine and KRAS siRNA, capable of navigating through tumor barriers and augmenting anticancer efficiency. When penetrating the tumor stroma barrier, the hyaluronic acid shell of the nanodelivery undergoes degradation by hyaluronidase in an extracellular matrix, triggering size tuning from large to small and charge tuning from negative to positive, thereby facilitating deeper penetration and cellular internalization. After endocytosis, the nanodelivery protonizes in the endo/lysosome, prompting rapid endo/lysosomal escape, effectively overcoming the lysosome barrier. Intracellular ROS further disrupt the nanodelivery, inducing its size tuning again from small to large and a positive charge decrease for high tumor retention and controlled drug release. The btND shows remarkable antitumor activity in pancreatic cancer mouse models, highlighting the efficacy of this approach in penetrating tumor barriers and enhancing anticancer outcomes.

Personalized Cancer Nanomedicine: Overcoming Biological Barriers for Intracellular Delivery of Biopharmaceuticals.

The success of personalized medicine in oncology relies on using highly effective and precise therapeutic modalities such as small interfering RNA (siRNA) and monoclonal antibodies (mAbs). Unfortunately, the clinical exploitation of these biological drugs has encountered obstacles in overcoming intricate biological barriers. Drug delivery technologies represent a plausible strategy to overcome such barriers, ultimately facilitating the access to intracellular domains. Here, an overview of the current landscape on how nanotechnology has dealt with protein corona phenomena as a first and determinant biological barrier is presented. This continues with the analysis of strategies facilitating access to the tumor, along with conceivable methods for enhanced tumor penetration. As a final step, the cellular barriers that nanocarriers must confront in order for their biological cargo to reach their target are deeply analyzed. This review concludes with a critical analysis and future perspectives of the translational advances in personalized oncological nanomedicine.

Indocyanine Green-Loaded Liposomes-Assisted Photoacoustic Computed Tomography for Evaluating In Vivo Tumor Penetration of Liposomal Nanocarriers.

Liposomes possess the potential to enhance drug solubility, prolong the duration of circulation, and augment drug accumulation at the tumor site through passive and active targeting strategies. However, there is a lack of studies examining the in vivo tumor penetration capabilities of liposomes of varying sizes, which hampers the development of drug delivery systems utilizing liposomal nanocarriers. Here, we present an indocyanine green (ICG)-loaded liposomes-assisted photoacoustic computed tomography (PACT) for directly evaluating the tumor penetration ability of liposomal nanocarriers in vivo. Through the utilization of microfluidic mixing combined with extrusion techniques, we successfully prepare liposomes encapsulating ICG in both large (192.6 ± 8.0 nm) and small (61.9 ± 0.6 nm) sizes. Subsequently, we designed a dual-wavelength PACT system to directly monitor the in vivo tumor penetration of large- and small-size ICG-encapsulated liposomes. In vivo PACT experiments indicate that ICG-loaded liposomes of smaller size exhibit enhanced penetration capability within tumor tissues. Our work presents a valuable approach to directly assess the penetration ability of liposomal nanocarriers in vivo, thereby facilitating the advancement of drug delivery systems with enhanced tumor penetration and therapeutic efficacy.

Fabrication of facile assembly shrinkable double-responsive nanoparticles: Investigation of anticancer activity in lung cancer cells and apoptosis induction

Nanoparticle-based delivery techniques have low stability, poor tumour penetration, and uncontrolled drug release. To address these issues, the present study designed HAD (the compound of Halloysite (HS), alginate oligosaccharides (AOS), and doxorubicin (DOX)). This shrinkable nanoparticle responds to changes in pH and enzyme activity in the tumour microenvironment. DOX, an anticancer drug in HAD, is durable in serum-comprising water solutions and readily accumulates in tumours in vitro, despite its small size (100 nm). Because of the abundance of lysozymes in the tumour extracellular matrix, HAD can be reduced from 100 nm to 30 nm (in size), allowing the drug to enter the tumour tissue more easily. In addition, once internalised by tumour cells, the DOX is rapidly released, and the acidic and enzymatic cellular microenvironment quickly kills the cancer cells. An excellent reduction in the A549 cells' dose-dependent viability observed the HAD's cytotoxic potential. The enhanced reactive oxygen species (ROS) accumulations and reduction of MMP were perceived in the HAD-treated cells. The improved caspase-3, − 9, and − 8 expressions were also seen in the HAD-exposed A549 cells. These findings show that HAD has been promised as a beneficial delivery method for cancer treatment since it can assure a regulated drug release specifically targeted to lung tumour cells.

A CTL-Inspired Killing System Using Ultralow-Dose Chemical-Drugs to Induce a Pyroptosis-Mediated Antitumor Immune Function.

A Cytotoxic T lymphocyte-inspired system capable of using ultralow-dose chemical drugs to manipulate cell death is needed to investigate the antitumor immunotherapy. Recent studies reveal pyroptosis promotes antitumor immune function. However, high-dose chemotherapy leads to cytokine release syndrome by pyroptosis. Therefore, pyroptosis-inducing ultralow-dose chemotherapy is potential in preclinical and clinical research, but its efficacy, safety, and the antitumor immune responses are not clear. Here, a near-infrared light controllable killing system (BIK system) is established by which ultralow-dose doxorubicin can be spatiotemporally transported to tumor cells and mediate efficient pyroptosis. This BIK system reduces total drug consumption to less than one-thirtieth the common dose in vitro. Moreover, this BIK system exhibited good tumor targeting and tumor penetration. This system is applied for pyroptosis-induced antitumor therapies, which shows less than ≈25µg kg-1 doxorubicin is sufficient for tumor regression with negligible injuries to major organs. The antitumor immune function are proven to correlate with the impressive efficacy of pyroptosis-inducing ultralow-dose chemotherapy. This study provides new insights into the design of nanoassisted systems for activating the antitumor immunity by microstimulation; the application of the BIK system suggests that ultralow-dose chemotherapy is sufficient for inducing a robust pyroptosis-mediated antitumor immunity.

Enhanced chemotherapy and anti-metastasis with in situ nanosphere-to-nanofiber transition

In situ morphological transformation-based drug delivery represents a cutting-edge strategy at the forefront of chemotherapy, integrating individual superiority from delivery stage-dependent, spatial-resolved morphologies. However, developing tumor-specific, in vivo morphologically transformable peptide-drug system realizing enhanced chemo-therapeutic efficacy with anti-metastasis capability is still challenging, primarily due to the shortfall in promising functional peptide candidates. By delicate control over the hydrophilic-hydrophobic balance of the peptide-drug conjugate and employing the high specificity of enzyme to transform peptide into high-ordered nanostructures on tumor site, herein, we rationally designed a novel prodrug FmocFFSGP-DOX with fibroblast activation protein-α (FAP-α, overexpressed in most epithelial tumors)-responsive nanosphere-to-nanofiber transition ability. The nanoparticle morphology formed at the first place allows for efficient tumor targeting via enhanced permeability and retention (EPR) effect along with good tumor penetration and easy cell uptake. Upon FAP-α cleavage at tumor site, DOX will be released to perform its function as a chemo-drug, while the remaining motif FmocFFSGP will be morphologically transformed to fibrous structures capable of activating the immune system and inhibiting tumor metastasis, which were systematically validated by our in vivo results. We anticipate that our strategy of FAP-α responsive nanosphere-to-nanofiber transition might be a promising alternative to promote tumor chemotherapeutic outcomes, and provide basis to the new-generation of peptide-based therapeutic agents for disease treatment in the future.

Oxygen self-supplied nanoparticle for enhanced chemiexcited photodynamic therapy

Photodynamic therapy (PDT) is a promising strategy for effective cancer treatment. However, it still faces severe challenges, including poor laser penetration and insufficient oxygen (O2) in solid tumors. Here, we constructed intelligent O2 self-supplied nanoparticles (NPs) for tumor hypoxia relief as well as effective chemiexcited PDT. Oxygen-carrying NPs (BSA@TCPO NPs) were obtained via the self-assembly of bovine serum albumin (BSA), bis[3,4,6-trichloro2-(pentyloxycarbonyl)phenyl]oxalate (TCPO), perfluorohexane (PFH), and chlorin e6 (Ce6). In H2O2-overexpressed tumor cells, TCPO in the NPs reacted with H2O2, releasing energy to activate the photosensitizer Ce6 and generate cytotoxic singlet oxygen (1O2) to kill tumor cells in a laser irradiation-independent manner. Moreover, the O2 carried by PFH not only reduced therapeutic resistance by alleviating tumor hypoxia but also increased 1O2 generation for enhanced chemiexcited PDT. The remarkable cytotoxicity to various cancer cell lines and A549 tumors demonstrated the advantage of BTPC in alleviating the hypoxic status and inhibiting tumor growth. Our results demonstrate that BTPC is a promising nanoplatform for cancer therapy.

Co-assembly of polymeric conjugates sensitizes neoadjuvant chemotherapy of triple-negative breast cancer with reduced systemic toxicity

Rational design of polymeric conjugates could greatly potentiate the combination therapy of solid tumors. In this study, we designed and prepared two polymeric conjugates (HT-DTX and PEG-YC-1), whereas the drugs were attached to the PEG via a linker sensitive to cathepsin B, over-expressed in TNBC. Stable nanostructures were formed by these two polymer prodrug conjugates co-assembly (PPCC). The stimuli-responsiveness of PPCC was confirmed, and the size shrinkage under tumor microenvironment would facilitate the penetration of PPCC into tumor tissue. In vitro experiments revealed the molecular mechanism for the synergistic effect of the combination of DTX and YC-1. Moreover, the systemic side effects were significantly diminished since the biodistribution of PPCC was improved after i.v. administration in vivo. In this context, the co-assembled nano-structural approach could be employed for delivering therapeutic drugs with different mechanisms of action to exert a synergistic anti-tumor effect against solid tumors, including triple-negative breast cancer. Statement of significance•Co-assembly of polymeric prodrug conjugates could form stable and homogeneous nanostructures, improving cellular uptake by cancer cells and in vivo tumor penetration and retention.•Co-delivery of neoadjuvant therapeutic drug (DTX) and HIF-1α inhibitor (YC-1) synergizes the anti-tumor effect by affecting HIF-1α expression and G2/M phase arrest.•Polymer prodrug conjugates co-assembly (PPCC) could reverse tumor resistance to neoadjuvant therapy, retard tumor progression, and prevent lung metastasis with reduced systemic toxicity in a murine triple-negative breast cancer model.

Development of LAG-3/FGL1 blocking peptide and combination with radiotherapy for cancer immunotherapy

Aside from antibodies, peptides show great potential as immune checkpoint inhibitors (ICIs) due to several advantages, such as better tumor penetration and lower cost. Lymphocyte-activation gene 3 (LAG-3) is an immune checkpoint which can induce T cell dysfunction through interaction with its soluble ligand fibrinogen like protein-1 (FGL1). Here, we found that LAG-3 expression was higher than programmed cell death protein 1 (PD-1) in multiple human cancers by TCGA databases, and successfully identified a LAG-3 binding peptide LFP-6 by phage display bio-panning, which specifically blocks the interaction of LAG-3/FGL1 but not LAG-3/MHC-II. Subsequently, d-amino acids were introduced to substitute the N- and C-terminus of LFP-6 to obtain the proteolysis-resistant peptide LFP-D1, which restores T cell function in vitro and inhibits tumor growth in vivo. Further, a bispecific peptide LFOP targeting both PD-1/PD-L1 and LAG-3/FGL1 was designed by conjugating LFP-D1 with PD-1/PD-L1 blocking peptide OPBP-1(8–12), which activates T cell with enhanced proliferation and IFN-γ production. More importantly, LFOP combined with radiotherapy significantly improve the T cell infiltration in tumor and elevate systemic antitumor immune response. In conclusion, we developed a novel peptide blocking LAG-3/FGL1 which can restore T cell function, and the bispecific peptide synergizes with radiotherapy to further enhance the antitumor immune response.

Spatiotemporal Quantification of HER2-targeting Antibody-Drug Conjugate Bystander Activity and Enhancement of Solid Tumor Penetration.

Antibody-drug conjugate (ADC) has had a transformative effect on the treatment of many solid tumors, yet it remains unclear how ADCs exert bystander activity in the tumor microenvironment. Here, we directly visualized and spatiotemporally quantified the intratumor biodistribution and pharmacokinetics of different ADC components by developing dual-labeled fluorescent probes. Mechanistically, we found that tumor penetration of ADCs is distinctly affected by their ability to breach the binding site barrier (BSB) in perivascular regions of tumor vasculature, and bystander activity of ADC can only partially breach BSB. Furthermore, bystander activity of ADCs can work in synergy with coadministration of their parental antibodies, leading to fully bypassing BSBs and enhancing tumor penetration via a two-step process. These promising preclinical data allowed us to initiate a phase I/II clinical study of coadministration of RC48 and trastuzumab in patients with malignant stomach cancer to further evaluate this treatment strategy in humans.