Abscopal Tumor Research Articles

Bioresponsive Self‐Reinforcing Sericin/Silk Fibroin Hydrogel for Relieving the Immune‐Related Adverse Events in Tumor Immunotherapy

AbstractDespite the immense potential of immune checkpoint blockade (ICB) therapy in tumor treatment, its widespread clinical application is currently limited by unsatisfactory curative effect and off‐target adverse effect. Herein, an injectable sericin (SS)/silk fibroin (SF) recombinant hydrogel, termed SF‐SS‐SMC hydrogel, is developed to enable local delivery of anti‐CD47 antibody (α CD47). The hydrogel displays self‐reinforcement in high H2O2 concentration of tumor microenvironment (TME), as the SS/Fe2+ supramolecular nanocomplex (SS‐SMC) inside the hydrogel converts H2O2 to reactive oxygen species (ROS), further triggering additional crosslinking among the SF polymers. Therefore, the SF‐SS‐SMC hydrogel has an in vivo retention time longer than 21 days and acts as a reservoir for the long‐term sustained release of α CD47. More importantly, the SF‐SS‐SMC hydrogel itself efficiently regulates the remodeling of a protumor immunosuppressive TME to an antitumoral TME through switching of tumor‐associated macrophages from an anti‐inflammatory M2 phenotype to a proinflammatory M1 phenotype without additional drugs. Based on the combined effect of sustained α CD47 release and TME reprogramming, the SF‐SS‐SMC hydrogel has satisfactory immunotherapeutic effects in the treatment of local, abscopal, remitting, and metastatic tumors. Further advantages, including low cost of production, simple fabrication, and ease of use, make it promising for commercial mass production.

Inhibition of STAT6 with Antisense Oligonucleotides Enhances the Systemic Antitumor Effects of Radiotherapy and Anti-PD-1 in Metastatic Non-Small Cell Lung Cancer.

Diverse factors contribute to the limited clinical response to radiotherapy (RT) and immunotherapy in metastatic non-small cell lung cancer (NSCLC), among which is the ability of these tumors to recruit a retinue of suppressive immune cells-such as M2 tumor-associated macrophages (TAM)-thereby establishing an immunosuppressive tumor microenvironment that contributes to tumor progression and radio resistance. M2 TAMs are activated by the STAT6 signaling pathway. Therefore, we targeted STAT6 using an antisense oligonucleotide (ASO) along with hypofractionated RT (hRT; 3 fractions of 12 Gy each) to primary tumors in three bilateral murine NSCLC models (Lewis lung carcinoma, 344SQ-parental, and anti-PD-1-resistant 344SQ lung adenocarcinomas). We found that STAT6 ASO plus hRT slowed growth of both primary and abscopal tumors, decreased lung metastases, and extended survival. Interrogating the mechanism of action showed reduced M2 macrophage tumor infiltration, enhanced TH1 polarization, improved T-cell and macrophage function, and decreased TGFβ levels. The addition of anti-PD-1 further enhanced systemic antitumor responses. These results provide a preclinical rationale for the pursuit of an alternative therapeutic approach for patients with immune-resistant NSCLC.

Oxygen‐Deficient Molybdenum Oxide Nanosensitizers for Ultrasound‐Enhanced Cancer Metalloimmunotherapy

AbstractOxygen‐deficient molybdenum oxide (MoOX) nanomaterials are prepared as novel nanosensitizers and TME‐stimulants for ultrasound (US)‐enhanced cancer metalloimmunotherapy. After PEGylation, MoOX‐PEG exhibits efficient capability for US‐triggered reactive oxygen species (ROS) generation and glutathione (GSH) depletion. Under US irradiation, MoOX‐PEG generates a massive amount of ROS to induce cancer cell damage and immunogenic cell death (ICD), which can effectively suppress tumor growth. More importantly, MoOX‐PEG itself further stimulates the maturation of dendritic cells (DCs) and triggeres the activation of the cGAS‐STING pathway to enhance the immunological effect. Due to the robust ICD induced by SDT and efficient DC maturation stimulated by MoOX‐PEG, the combination treatment of MoOX‐triggered SDT and aCTLA‐4 further amplifies antitumor therapy, inhibits cancer metastases, and elicits robust immune responses to effectively defeat abscopal tumors.

Oxygen-Deficient Molybdenum Oxide Nanosensitizers for Ultrasound-Enhanced Cancer Metalloimmunotherapy.

Oxygen-deficient molybdenum oxide (MoOX ) nanomaterials are prepared as novel nanosensitizers and TME-stimulants for ultrasound (US)-enhanced cancer metalloimmunotherapy. After PEGylation, MoOX -PEG exhibits efficient capability for US-triggered reactive oxygen species (ROS) generation and glutathione (GSH) depletion. Under US irradiation, MoOX -PEG generates a massive amount of ROS to induce cancer cell damage and immunogenic cell death (ICD), which can effectively suppress tumor growth. More importantly, MoOX -PEG itself further stimulates the maturation of dendritic cells (DCs) and triggeres the activation of the cGAS-STING pathway to enhance the immunological effect. Due to the robust ICD induced by SDT and efficient DC maturation stimulated by MoOX -PEG, the combination treatment of MoOX -triggered SDT and aCTLA-4 further amplifies antitumor therapy, inhibits cancer metastases, and elicits robust immune responses to effectively defeat abscopal tumors.

Spatiotemporal local and abscopal cell death and immune responses to histotripsy focused ultrasound tumor ablation.

Histotripsy is a novel focused ultrasound tumor ablation modality with potent immunostimulatory effects. To measure the spatiotemporal kinetics of local andabscopal responses to histotripsy, C57BL/6 mice bearing bilateral flank B16 melanoma or Hepa1-6 hepatocellular carcinoma tumors were treated with unilateral sham or partial histotripsy. Treated and contralateral untreated (abscopal) tumors were analyzed using multicolor immunofluorescence, digital spatial profiling, RNA sequencing (RNASeq), and flow cytometry. Unilateral histotripsy triggered abscopal tumor growth inhibition. Within the ablation zone, early high mobility group box protein 1 (HMGB1) release and necroptosis were accompanied by immunogenic cell death transcriptional responses in tumor cells and innate immune activation transcriptional responses in infiltrating myeloid and natural killer (NK) cells. Delayed CD8+ T cell intratumoral infiltration was spatiotemporally aligned with cancer cell features of ferroptosis; this effect was enhanced by CTLA-4 blockade and recapitulated in vitro when tumor-draining lymph node CD8+ T cells were co-cultured with tumor cells. Inoculation with cell-free tumor fractions generated by histotripsy but not radiation or freeze/thaw conferred partial protection from tumor challenge. We propose that histotripsy may evoke local necroptotic immunogenic cell death, priming systemic adaptive immune responses and abscopal ferroptotic cancer cell death.

A dual-sensitive nanoparticle-mediated deepening synergistic therapy strategy involving DNA damage and ICD stimuli to treat triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is one of the most aggressive cancers with an immunosuppressive microenvironment, and achieving a satisfactory effect from monotherapies, such as chemotherapy, photodynamic therapy (PDT) or immunotherapy, remains difficult. To solve this puzzle, a deepening synergistic therapy strategy of DNA damage and immunogenic cell death (ICD) stimuli was proposed. We engineered a doxorubicin (DOX) and 4-(hydroxymethyl) phenylboronic acid pinacol ester (PBAP) prodrug polymer, and encapsulated chlorin e6 (Ce6) to obtain the hyaluronidase (HAase) and H2O2 dual-sensitive responsive nanoparticles (Ce6/HDP NPs). The NPs displayed efficient intratumoral accumulation and cellular internalization properties due to the active targeting of the hyaluronic acid (HA). The dual DNA damage of the chemotherapy and ROS production directly caused tumor cell apoptosis. The strong ICD stimuli, which were induced by ROS production and GSH depletion, generated an amplified immunogenicity to activate tumor immunotherapy in vivo. In this manner, the NPs could significantly inhibit primary tumor, abscopal tumor, pulmonary metastasis and recurrent tumor in a subcutaneous 4T1 tumor model, with effective biosafety. This study has provided a promising deepening synergistic therapy strategy against TNBC.

Study of epirubicin sustained-release chemoablation in tumor suppression and tumor microenvironment remodeling.

Although intratumoral chemoablation can obtain an impressive therapeutic effect, there is still incomplete ablation and tumor recurrence in some patients. This could be due to the short retention time of the drug in the tumor, the limited distribution of intratumoral drugs, and, beyond that, the immunotolerance caused by the tumor microenvironment (TME). There is still an urgent need to find an optimal drug sustained-release carrier and figure out the impact of regional injection to TME. In this study, we supposed to use polyethylene glycol (PEG) hydrogel as a drug carrier to improve the retention time of the drug to extend the exposure of tumor cells and investigate the feasibility of combination local Epirubicin injection with anti-PD-L1. The results revealed obvious tumor suppression based on the tumor volume and the inhibition time of tumor growth in the A549 lung cancer mouse model after local injection. Furthermore, the enhanced antitumor effects of the combination of systematic anti- programmed death ligand 1 (PD-L1) therapy with local chemoablation (EPI-GEL/PD-L1) for abscopal tumor reduction in the 4T1 breast model were also observed. Flow cytometry analysis of the tumor and blood samples showed significant variations in the proportions of PD-L1+ and CD3+CD8+PD-1+ cells before and after anti-PD-L1 therapy. On day 4 after local injection of the EPI gel, the expression of PD-L1 in abscopal tumors was upregulated, while the expression of PD-L1 in bilateral tumors in mice was significantly reduced after anti-PD-L1 treatment. The proportion of CD3+CD8+PD-1+ cells in the tumor and circulating blood in the EPI-GEL/PD-L1 group was decreased compared with that in the EPI-GEL (single injection of epirubicin) group. The combination of local injection of the chemoablation agent with anti-PD-L1 monoclonal antibody (mAb) therapy may strengthen the antitumor activity, and the use of PEG hydrogel as the drug carrier can extend the retention time of the chemoablation agent around the tumor, maintaining a long-term tumor-killing activity.

Carrier-Free Nanoplatform via Evoking Pyroptosis and Immune Response against Breast Cancer.

Pyroptosis, as a novel mode of cell death, has been proven to have impressive antitumor effects. Dying cells undergoing pyroptosis can elicit antitumor immunity by the release of tumor-associated antigens (TAAs) and damage-associated molecular patterns (DAMPs). Accordingly, developing an effective, stable, and controllable nanoplatform that can promote these two side effects is a promising option for cancer therapy. In this study, we designed a carrier-free chemo-photodynamic nanoplatform (A-C/NPs) using a co-assembly strategy with cytarabine (Ara-C) and chlorin e6 (Ce6) to induce pyroptosis and a subsequent immune response against breast cancer. Mechanistically, A-C/NPs can trigger GSDME-mediated pyroptosis in a controllable manner through reactive oxygen species (ROS) accumulation, causing immunogenic cell death (ICD), in which dying cells release high-mobility group box 1 (HMGB1), adenosine triphosphate (ATP), and calcitonin (CRT). Additionally, Ara-C can stimulate the maturation of cytotoxic T lymphocytes to act synergistically with Ce6-mediated immunogenic cell death (ICD), collectively augmenting the anticancer effect of A-C/NPs. The A-C/NPs showed excellent suppressive effects on the growth of orthotopic, abscopal, and recurrent tumors in a breast cancer mouse model. The chemo-photodynamic therapy (PDT) using the proposed nanomedicine strategy could be a novel strategy for triggering pyroptosis and improving the global anticancer immune response.

Mechanical destruction using a minimally invasive Ultrasound Needle induces anti-tumor immune responses and synergizes with the anti-PD-L1 blockade

Immune checkpoint inhibitors (ICIs) have been widely used in treating various tumors; however, the objective response rate of ICIs is less than 40%. In this study, we attempted to induce anti-tumor immune responses using an improved ultrasonic horn device, Ultrasound Needle (UN). We tested its synergistic anti-tumor efficacy with an anti-PD-L1 antibody in a mouse tumor model. Under different parameters, UN treatment selectively induced mechanical destruction and thermal ablation effects on tumor tissues. The mechanical destruction effect of UN treatment increased the infiltration of CD8+ T cells in tumors and relieved the immunosuppressive tumor microenvironment. It also induced systemic anti-tumor immune responses and enhanced the therapeutic efficacy of the anti-PD-L1 antibody in both local and abscopal tumors. The mechanical destruction effect of UN treatment resulted in the release of damage-associated molecular patterns and promoted dendritic cells (DCs)-based antigen presentation. Depletion of DCs or CD8+ T cells eliminated the anti-tumor immune responses induced by UN treatment and weakened the synergistic anti-tumor efficacy with anti-PD-L1 antibody. Therefore, minimally invasive UN may provide a new therapeutic modality for ultrasound-assisted immunotherapy.

Bacterial Metabolism-Initiated Nanocatalytic Tumor Immunotherapy

HighlightsNovel-designed microbiotic nanomedicine capable of targeting hypoxic tumor sites.First paradigm of bacterial metabolism-initiated and photothermal therapy-enhanced nanocatalytic therapy for ablating tumors and inducing immunogenic cell death.Strong antitumor immunity activation for abscopal tumors therapy.

Cancer cell membrane camouflaged biomimetic nanosheets for enhanced chemo-photothermal-starvation therapy and tumor microenvironment remodeling

Tumor microenvironment (TME) featured by dense extracellular matrix (ECM), high interstitial pressure, hypoxia, and immunosuppression hinders the infiltration of nanoparticles (NPs) into tumors, impairing the efficacy of chemotherapy or phototherapy. To overcome these obstacles, we propose a novel biomimetic nano-carrier, B16F10 cell membrane camouflaged heparin-3-bromopyruvate conjugate modified graphene oxide (GOHep-3BP@membrane, GBM), for the targeted delivery of etoposide (EPT). EPT/GBM accumulates in tumor tissue and is internalized into B16F10 cells relying on homologous targeting ability. GO-mediated hyperthermia could accelerate the release of EPT, destruct ECM, dilate blood vessels, increase oxygen supply, and induce immunogenic cell death (ICD). The acylhydrazone bond-conjugated 3BP is released in acidic environment, suppressing glycolysis for starvation therapy, and reducing lactate efflux to alleviate immunosuppression. The released EPT entered the cell nuclei to exert a chemotherapeutic effect and downregulated the expression of programmed death ligand 1 (PD-L1) by inhibiting epithelial-mesenchymal transition (EMT)/β-catenin/STT3/PD-L1 signaling. EPT/GBM plus near infrared (NIR) laser treatment activated T lymphocytes and downregulated M2 tumor-associated macrophage (TAM), showing significant efficacy against primary tumors, abscopal tumors and lung metastases. In summary, this study presented a novel combinational strategy that integrated PTT, chemotherapy, starvation therapy and immunotherapy in one system, providing a new perspective for targeted-therapy of melanoma.

Improvement of radiotherapy with an ozone-carried liposome nano-system for synergizing cancer immune checkpoint blockade

Radiotherapy is a compatible regimen for synergizing immune checkpoint blockade therapy by promoting immunogenic cell death. To improve the efficiency of irradiation-induced neoantigen generation, we designed and developed an ozone-carrying liposome perfluorodecalin (PFD) nano-system (O3_PFD@Liposome) which promoted ozone solubility by 18.4-fold compared to that in water solution. The O3_PFD@Liposome particle remarkably improved the irradiation-induced hydroxyl radical generation. Evaluation of sub-cellular biodistribution indicated that the nano-system could be efficiently internalized by tumor cells. Upon released inside tumor cells, ozone generated reactive oxygen species under the stimulation of X-ray irradiation. Notably, O3_PFD@Liposome significantly prompted anti-tumor efficacy of radiotherapy without inducing severe adverse effects. The combo regimen with radiotherapy and ozone potently enhanced the infiltration of lymphocytes in the tumor microenvironment by inducing immunogenic cell death, releasing neoantigens, and relieving hypoxia symptom. Consequently, the combination of ozone-fueled irradiation and PD-1 blockade synergistically inhibited the growth of primary and abscopal tumors.

Selective Agonism of Intermediate-Affinity IL-2 Receptor Promotes Systemic Antitumor Responses in Combination with Radiotherapy in Metastatic Lung Cancer

<h3>Purpose/Objective(s)</h3> For immune checkpoint inhibitor-resistant patients, adding interleukin-2 (IL-2) may aid antitumor responses by stimulating effector T cells and NK cells. Unfortunately, high-dose IL-2 therapy has limited clinical utility due to adverse events and stimulation of immunosuppressive regulatory T cells (T_regs). Nemvaleukin alfa (nemvaleukin) is a novel engineered cytokine that selectively binds to the intermediate-affinity IL-2 receptor, preferentially activating and expanding antitumor CD8⁺ T and NK cells, with minimal expansion of T_regs. Thus, Nemvaleukin may be beneficial in combination with radiation therapy (RT) and immunotherapy. This study aimed to evaluate the antitumor activity and mechanism of action of the combination of RDB 1462 (the murine ortholog of Nemvaleukin, a.k.a. mNemvaleukin), RT, and immunotherapy in multiple mouse tumor models. <h3>Materials/Methods</h3> In a bilateral 344SQ lung adenocarcinoma murine model, primary tumors were treated with high-dose RT (HDRT; 12 Gy per fraction for 3 fractions), and secondary tumors were observed for evidence of abscopal effects. In another model for low absolute lymphocyte count (ALC), we used 2 Gy total body irradiation (TBI) three days before HDRT and RDB 1462. In a third MC38-gp100 mouse model, tumors were irradiated with low-dose RT (LDRT; 3 fractions of 1 Gy each) followed by pmel-1 T cell infusion after 24 hours, and RDB 1462 administration 12 hours thereafter. We performed immune phenotyping by flow cytometry; analyzed 770 immune-related genes using a multiplex analysis platform; also performed T cell receptor (TCR) repertoire analysis. Serum pro-inflammatory cytokine markers were analyzed by 23-plex kit. <h3>Results</h3> In 344SQ-parental lung adenocarcinoma, we combined HDRT with escalating doses of RDB 1462 at various timepoints, resulting in significant tumor reduction in both irradiated and unirradiated (abscopal) tumors compared with HDRT or RDB 1462 therapy alone. HDRT+RDB 1462 increased the numbers and activity of tumor-specific CD8⁺ T cells, NK cells, and memory T cells without drastically increasing T_regs, as evidenced by peripheral and tumor-infiltrating immune phenotypic and functional analyses. T cells showed increased receptor clonality and diversity in groups receiving HDRT+RDB 1462. The addition of anti-PD-1 to HDRT+RDB 1462 further increased antitumor control of both irradiated and abscopal tumors, reduced lung metastases, and prolonged survival. The antitumor effects of HDRT and RDB 1462 persisted even in mice with low ALC. The addition of LDRT contributed to increased tumor-specific T cells that were expanded by RDB 1462 with increased infiltration of Thy1.1⁺ CD8⁺ T cells. <h3>Conclusion</h3> The addition of Nemvaleukin therapy may enhance responses to RT alone and in combination with anti-PD-1 or adoptive T cell therapy.

Tumor extracellular matrix-targeted nanoscavengers reverse suppressive microenvironment for cocktail therapy

Extracellular matrix (ECM) is not only a natural bulwark to shield solid tumor cells from therapeutic agents and cytotoxic T lymphocytes (CTLs), but also one of the key factors that cause tumor hypoxic environment, severely hindering photodynamic reactions and immune responses. In this work, multifunctional nanoscavengers (ECMT NS) consisting of digestive enzyme chymotrypsin, catalase, calcium peroxide nanoparticles, photosensitizer chlorin e6, and tumor ECM-targeting CLT1 peptide are rationally designed with several benefits for enhanced cocktail calcium ion/photodynamic/immune therapy. The scavengers can effectively “clear” tumor ECM via digestive proteolytic enzyme- and reactive oxygen species-mediated pathways, deepening tumor penetration of the scavengers and CTLs. Thanks to the ECM destruction and oxygen self-supply capability of ECMT NS, the hypoxia in tumors is attenuated, thus improving photodynamic therapeutic efficiency and downregulating immunosuppressive factors. Moreover, the combination of calcium ion overload and photodynamic therapy enriches damage-associated molecular patterns, which promotes CTL activation to inhibit abscopal tumor growth and lung metastasis. The presented ECM destruction strategy provides a solution to overcome the tumor suppressive microenvironment.

Pivotal Roles of Tumor-Draining Lymph Nodes in the Abscopal Effect from Combined Immunotherapy and Radiotherapy

<h3>Purpose/Objective(s)</h3> Currently, due to synergy enhancement of anti-tumor effects and potent stimulation of abscopal effects, combination therapy of irradiation and PD-1/L1 immune checkpoint inhibition (iRT) has revolutionized the therapeutic guidelines. It's been demonstrated that tumor draining lymph nodes (TDLNs) are essential for effective antitumor immunity induced by radiotherapy, immunotherapy or iRT. Given that the function of TDLNs in iRT is still unclear, we investigated the role of TDLNs in iRT induced abscopal effects and the possible mechanisms. <h3>Materials/Methods</h3> The function of TDLNs was evaluated using unilateral or bilateral MC38 and B16F10 subcutaneous tumor models with or without indicated TDLNs. The flow cytometry, multiple immunofluorescence analysis and multiplex analysis were utilized to detect the composition and function of the immune cells in the primary and abscopal tumor microenvironments. And we tempted to interrogate the possible mechanisms via RNA-seq of tumor infiltrated lymphocytes and TDLNs. Finally, we assessed the prognosis of breast cancer patients subjected to various numbers of TDLNs removal. <h3>Results</h3> We found that monotherapy or iRT deficient of TDLNs restored the tumor progression to a mild degree, and bilateral TDLNs removal rather than unilateral TDLNs removal substantially curtailed iRT-stimulated anti-tumor effects and abscopal effects. Moreover, we showed that with the absence of TDLNs, the infiltration of CD45⁺ cells and CD8⁺ T cells was substantially reduced in both the primary and abscopal tumors, and the anti-tumor function of CD8⁺ T cells was attenuated as well. Additionally, the polarization of tumor-associated macrophages in primary and abscopal tumors relied on intact bilateral TDLNs. RNA-seq data indicated that impaired infiltration and anti-tumor effects of immune cells may partially attribute to the altered secretion of tumor microenvironments. <h3>Conclusion</h3> Our results highlight that TDLNs play a critical role in iRT via promoting the infiltration of CD8⁺ T-cells and maintaining the M1/M2 macrophage ratio. Currently, surgical removal or radiation ablation of TDLNs are standard treatments in various types of cancers and are regarded to avoid tumor metastasis and promote prognosis. Based on our findings, whether the regional TDLNs should be preserved in clinical practice should be deliberately considered.

The Combination Timing of Radio-Immunotherapy Determines Immune Microenvironment Remodeling and Abscopal Effect through Eosinophils

<h3>Purpose/Objective(s)</h3> Several studies have confirmed the abscopal effect of tumor shrinkage outside the irradiated field induced by local radiotherapy (RT) combined with immunotherapy. The timing of the combination, including concurrent and sequential treatment, may affect the anti-tumor efficacy of radiotherapy and immune checkpoint inhibitors (ICIs). However, the optimal timing of RT combined with immunotherapy to enhance the abscopal effect and the underlying mechanism is still unknown. <h3>Materials/Methods</h3> The animal model of bilateral subcutaneous tumor of colon cancer (MC38) in C57BL/6J mice were randomly divided into four groups: PD-1 therapy (P1) group, radiotherapy (unilateral irradiation, 8Gy × 3F, the same below) concurrent with anti-PD-1 therapy (Con.) group, anti-PD-1 therapy one week after radiotherapy (Seq.1) group and anti-PD-1 therapy two weeks after radiotherapy (Seq.2) group. RNA sequencing was employed to identify differential genes. The changes of the immune microenvironment of tumor-draining lymph nodes (TDLN) and tumors were detected by flow cytometry. The expression of chemokine receptors, ligands, and cytokines was detected by qPCR, western blot, and ELISA. Anti-mouse Siglec-F antibody was used to neutralize the eosinophils in vivo. <h3>Results</h3> The results showed that the survival benefit of sequential PD-1 inhibitor after RT was higher than that of the Con. group and P1 group., the survival benefited most in Seq.1 group, particularly. Tumor growth on both sides was significantly inhibited in Seq.1 group compared with the Con. group, P1 group, and Seq2. group. Furthermore, a combination of RT with anti-PD-1 inhibitor induced changes of immune microenvironment in irradiated tumor, abscopal tumor and TDLN. In the Seq.1 group, the tumor immune microenvironment was reshaped, including increased eosinophils and CD8+T cells infiltration, while decreased Treg, MDSCs, and TAMs frequency. Correspondingly, the expression of crucial chemokine receptors and ligands involved in chemotaxis of eosinophils and CTL CD8+T cells was up-regulated in tumors of mice in the Seq.1 group. After eosinophil neutralization in vivo, the survival of mice in Seq.1 group was significantly shortened. The anti-tumor effect and abscopal effect were significantly weakened, accompanied by deduction of the infiltration of T cells, especially cytotoxicity CD8+T cells in the immune microenvironment. <h3>Conclusion</h3> Our results showed that RT combined with ICIs could induce a synergistic anti-tumor effect. Sequential PD-1 inhibitor one week after RT could enhance the anti-tumor effect most, including the abscopal effect. The mechanism related to eosinophils recruitment established a tumor-suppressive immune microenvironment mainly through enrichment of anticancer T lymphocytes in abscopal tumors. This study provides an insight into clinical precision treatment in a combination of RT and immunotherapy.

A minimally designed PD-L1-targeted nanocomposite for positive feedback-based multimodal cancer therapy

Combining immune checkpoint blockade therapy (ICBT) with other treatment modalities through nanotechnology offers an opportunity to further boost immunity for effective cancer treatment. Herein three-in-one programmed death-ligand 1 (PD-L1)-targeted nanocomposite (NC) was minimally fabricated through self-assembling photothermal agent black phosphorus nanosheet (BPN), chemotherapeutic agent Polymetformin (PolyMet), and immune checkpoint inhibitor anti-PD-L1 antibody (aPD-L1), avoiding the easy degradability of BPN through bridging the electrostatic interaction between PolyMet and BPN. The prepared aPD-L1-PolyMet/BPN NC could precisely target primary tumor through the interaction between aPD-L1 and PD-L1 based on ICBT, and the targeting efficacy was gradually reinforced due to the PD-L1 upregulation in tumor sites after photothermal therapy (PTT), ensuring positive feedback-mediated multimodal antitumor effect during continuous treatment loops. Moreover, the combinational therapy composed of photothermal immunotherapy (PIT), chemotherapy and ICBT strengthened the antitumor efficacy owing to their synergistic mechanism. Meanwhile, the generated positive feedback property during treatment displayed powerful antitumor effect, which not only inhibited primary and abscopal tumor progression, but also prevented tumor metastasis and promoted long-term tumor immune memory establishment. Therefore, this antitumor NC provided a prospective insight into the field of multimodal cancer therapy through rational and minimal design.

A single-beam of light priming the immune responses and boosting cancer photoimmunotherapy.

Mirroring the rapid clinical performance, immune checkpoint blockade (ICB) leads a remarkable clinical advance in combating cancer, but suffers poor response in most cancers. The low presence of tumor-infiltration lymphocytes and the poor immunogenicity in tumor microenvironment (TME) are the main factors hindering the effectiveness of ICB in the treatment of immunological "cold" tumors. Aiming at boosting immune response via TME modulation, we report a near-infrared laser-guided photoimmuno-strategy in which synergistic phototherapy, immune adjuvant, and ICB are integrated into one versatile nanoporphyrin platform. The prepared nanoporphyrins are self-assembled from purpurin18-lipids and have photodynamic/photothermal and immunomodulatory effects that can be tuned under a single laser irradiation, concomitant with fluorescence or MSOT imaging. In this work, the contributions of each component in the nanoporphyrin platform were specified. In particular, phototherapy-driven in situ tumor cell death provided abundant tumor-associated antigens to initiate immune responses. With the assist of spatiotemporally delivered immune adjuvant, phototherapy potentiated tumor immunogenicity, reprogrammed "cold" tumors into "hot" ones, and sensitized tumors to ICB therapy. Further combined with PD-L1 blockade, the photoimmune-strategy substantially stimulated tumor-specific immune-responses and long-term immunological memory against primary tumor, abscopal tumor as well as metastatic foci. Such single light-primed photoimmunotherapy offers a promising solution to overcome common hurdles in ICB treatment and can potentially be integrated into existing clinical practice.

Tumor-Specific Immunoenhancing Effects after Local Cryoablation for Metastatic Bone Tumor in a Mouse Model.

We investigated the abscopal effect after cryoablation (CA) on bone metastasis using a mouse model. Breast cancer cells were implanted in the bilateral tibiae of mice. The left tumor was treated locally with CA, and the right abscopal tumor (AT) was left untreated. The mice were divided into four groups based on the combination of CA and intraperitoneal administration of anti-PD-1 antibody (PD) as treatment interventions (Control, CA, PD, and CA + PD). The reduction ratio of the size of AT, the quantitative immune effects at enzyme-linked immunospot (ELISPOT) assay, and the intensity of infiltration of immune-related cells to AT were compared among the groups. CA alone showed a significant immunoenhancing effect on the volume change ratio of AT from day 0 to day 14 (Control-CA: p < 0.05), ELISPOT assay (Control-CA: p < 0.01), and CD4+ cell count in immunostaining (Control-CA: p < 0.05). CA alone showed no significant immunoenhancing effect on CD8+ and Foxp3+ cell counts in immunostaining, but the combination of CA and PD showed a significant immunoenhancing effect (Control-CA + PD: p < 0.01 [CD8, Foxp3]). The results suggested that the abscopal effect associated with the local cryotherapy of metastatic bone tumors was activated by CA and enhanced by its combination with PD.

Hydrazide-manganese coordinated multifunctional nanoplatform for potentiating immunotherapy in hepatocellular carcinoma

Immune checkpoint blockade (ICB)-based immunotherapy is a revolutionary therapeutic strategy for hepatocellular carcinoma (HCC). However, tumor immune tolerance and escape severely restrict the therapeutic efficacy of ICB therapy. It is urgent to explore new strategies to potentiate ICB therapy in HCC. Herein, we developed manganese oxide-crosslinked bovine albumin/hyaluronic acid nanoparticles (BHM) by an innovative hydrazide-manganese coordination and desolvation process. Successive loading of doxorubicin (DOX) and indocyanine green (ICG) was achieved via hydrazone linkage and electrostatic interactions, respectively, obtaining DOX/ICG-coloaded BHM nanoplatform (abbreviated as BHMDI). The BHMDI nanoplatform exhibited a high drug content (>46%) and pH/reduction dual-responsive drug release behavior. The nanoplatform could efficiently alleviate tumor hypoxia by catalytic decomposition of intracellular H2O2 to O2 and significantly improve BHMDI-based photodynamic chemotherapy efficacy. The BHMDI nanoplatform downregulated the proportion of alternatively activated (M2) macrophages in tumors and simultaneously induced immunogenic death of HCC cells, thus promoting the maturation of dendritic cells and ensuing priming of CD4+ and CD8+ T cells. Importantly, programmed death-1 (PD-1) blockade in combination with BHMDI nanoplatform not only eradicated primary tumors but inhibited tumor recurrence, abscopal tumor growth and lung metastasis of HCC by triggering robust systemic antitumor immunity. This work proved the feasibility of BHMDI-based photodynamic chemotherapy for potentiating PD-1 blockade immunotherapy by reversing hypoxic and immunosuppressive tumor microenvironment.