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Immune checkpoint inhibitors (ICIs) have contributed significantly to the treatment of various types of cancer, including skin cancer. However, not all patients respond; some patients do not respond at all (primary resistance), while others experience recurrence after the initial response (acquired resistance). Therefore, overcoming ICI resistance is an urgent priority. Numerous ICI resistance mechanisms have been reported. They are seemingly quite complex, varying from patient to patient. However, most involve T cell activation processes, especially in the tumor microenvironment (TME). ICIs exert their effects in the TME by reactivating suppressed T cells through inhibition of immune checkpoint molecules, such as cytotoxic T-lymphocyte antigen-4 (CTLA-4) and programmed cell death protein 1 (PD-1). Thus, this review focuses on the resistance mechanisms based on the T cell activation process. Here, we classify the main mechanisms of ICI resistance into three categories based on: (1) antigen recognition, (2) T cell migration and infiltration, and (3) effector functions of T cells. By identifying and understanding these resistance mechanisms individually, including unknown mechanisms, we seek to contribute to the development of novel treatments to overcome ICI resistance.

Fusobacterium nucleatum has been detected in 8%‐13% of human colorectal cancer, and shown to inhibit immune responses against primary colorectal tumors in animal models. Thus, we hypothesized that the presence of F. nucleatum might be associated with reduced T cell density in colorectal cancer liver metastases (CRLM). We quantified F. nucleatum DNA in 181 CRLM specimens using quantitative PCR assay. The densities of CD8+ T cells, CD33+ cells (marker for myeloid‐derived suppressor cells [MDSCs]), and CD163+ cells (marker for tumor‐associated macrophages [TAMs]) in CRLM tissue were determined by immunohistochemical staining. Fusobacterium nucleatum was detected in eight (4.4%) of 181 CRLM specimens. Compared with F. nucleatum‐negative CRLM, F. nucleatum‐positive CRLM showed significantly lower density of CD8+ T cells (P = .033) and higher density of MDSCs (P = .001). The association of F. nucleatum with the density of TAMs was not statistically significant (P = .70). The presence of F. nucleatum is associated with a lower density of CD8+ T cells and a higher density of MDSCs in CRLM tissue. Upon validation, our findings could provide insights to develop strategies that involve targeting microbiota and immune cells for the prevention and treatment of CRLM., Fusobacterium nucleatum was detected in eight (4.4%) of 181 colorectal cancer liver metastasis tissue. We found that the presence of F. nucleatum was associated with lower CD8+ T cell density and greater densities of both myeloid‐derived suppressor cells and tumor‐associated macrophages.

Regulated cell death (RCD) is a vital event in various physiological and pathological processes. Ferroptosis is a newly described RCD, which is driven by iron accumulation and unrestricted lipid peroxidation. The interaction between ferroptosis and immunity has been a topic of substantial interest since its discovery in 2012. It has become increasingly evident that ferroptosis is critically involved in the regulation of antitumor immunity and may provide potential strategies in immunotherapy. Ferroptosis could release various damage-associated molecular patterns (DAMPs) or lipid metabolites to regulate the cellular immune response, validating its role as a form of immunogenic cell death (ICD). Specifically, the oxygenated membrane lipids on ferroptotic cells could mediate the phagocytosis by macrophages to maintain the immune responses. Additionally, immune checkpoint inhibitor therapy may sensitize cancer cells to ferroptosis, while ferroptosis might contribute to tumor immune evasion by directly interfering with the function of various immune cells. Based on these insights, we provided a comprehensive review on the interaction patterns between ferroptosis and immunity, which may not only offer insight into the underlying regulatory mechanisms but also facilitating the development of ferroptosis-based antitumor therapeutics.

Several studies have reported that tissue‐resident memory T cells (TRM cells) or tertiary lymphoid structures (TLSs) are associated with a good prognosis. The aim of this study was to clarify the association of TRM cells and TLSs in the tumor immune microenvironment in gastric cancer (GC). We performed immunohistochemical and immunofluorescence staining to detect the presence of CD103+ T cells and to assess the association between CD103+ T cells and TLSs. CD103+ T cells were observed in the tumor epithelium accompanied by CD8+ T cells and were associated with a better prognosis in GC. Furthermore, CD103+ T cells were located around TLSs, and patients with CD103high had more rich TLSs. Patients who had both CD103high cells and who were TLS‐rich had a better prognosis than patients with CD103low cells and who were TLS‐poor. Moreover, for patients who received PD‐1 blockade therapy, CD103high and TLS‐rich predicted a good response. Flow cytometry was performed to confirm the characteristics of CD103+CD8+ T cells and showed that CD103+CD8+ T cells in GC expressed higher levels of PD‐1, granzyme B, and interferon‐γ than CD103−CD8+ T cells. Our results suggested that CD103+CD8+ cells in GC are correlated with TLSs, resulting in enhanced antitumor immunity in GC., Many CD103+ T cells were observed in the tumor epithelium accompanied by CD8+ T cells and were located around tertiary lymphoid structures (TLSs). Patients with a combination of CD103high and TLS‐rich had a good prognosis.

Immune checkpoint inhibitors (ICIs) activate host antitumor immunity to kill tumor cells. However, ICI therapy may be accompanied by a series of immunotherapy‐related adverse effects (irAEs) caused by activated autoreactive T cells. Glucocorticoids are the mainstream therapy for irAEs. However, the usage, dosage and course of treatment of irAEs with glucocorticoids differs from those used in classic autoimmune diseases. Furthermore, the long‐term use of large doses of glucocorticoids may cause serious adverse effects. In this article, the mechanism, dosage forms, adverse effects and management of glucocorticoids are described in detail, providing references and suggestions for oncologists to use glucocorticoids in the treatment of irAEs., Glucocorticoids are the mainstream therapy for irAEs. We described the mechanism, dosage forms, adverse effects and management of glucocorticoids. We aimed to provide references and suggestions for oncologists to use glucocorticoids in the proper treatment of irAEs.

Background Recombinant human calcineurin B subunit (rhCNB) has been shown to be an immune‐stimulatory protein promoting cytokine production and inducing phenotypic maturation of Dendritic cells (DCs). In vivo, it has good antitumor efficacy, and has potential as an antitumor drug. Exogenous rhCNB was found to be internalized into tumor cells via the Toll‐like receptor 4 (TLR4) complex, but it was not known whether its immuno‐modulatory and antitumor functions involved entry by this same route. Methods The production and secretion of the cytokines and chemokines in innate immune cells induced by rhCNB were determined by ELISA, and the expression of CD40, CD80, CD86, and MHCII was analyzed by FACs. Experimental Lewis lung cancer (LLC) model was prepared in C57 BL/6 wild‐type (WT) mice, TLR4−/− mice or their littermates by the inoculation of LLCs in their right armpit, and then administrated daily intraperitoneal injections (0.2 mL) of normal saline, rhCNB 20 mg/kg, and rhCNB 40 mg/kg, respectively. Results Recombinant human calcineurin B subunit promoted the production of antitumor cytokines by innate immune cells, and culture supernatants of rhCNB‐stimulated immune cells induced apoptosis of LLCs. In addition, rhCNB up‐regulated CD40, CD80, CD86, and MHCII expression in macrophages and DCs in TLR4+ cells but failed to do so in TLR4 deficient cells. rhCNB also induced the formation of CD4+ and CD8+T cells in splenocytes from WT mice, but not from TLR4‐deficient littermates. Intraperitoneal administration of WT C57BL/6 mice with rhCNB resulted in a 50% reduction in LLC tumor growth, but failed to inhibit tumor growth in TLR4−/− littermates. Conclusions The in vivo antitumor and immunomodulatory effects of rhCNB are mediated by the TLR4. This conclusion is important for the further understanding and development of rhCNB as an antitumor drug.

Oncolytic viruses (OVs) are promising new therapeutic agents in the field of malignant tumor treatment. OVs can achieve the goal of targeted therapy by selectively killing tumor cells and inducing specific antitumor immunity. The key roles of OVs are tumor targeting and tumor killing mechanisms. Recently, molecular biotechnology has been used to optimize the transformation of wild virus strains in order to ensure a stronger oncolytic effect and lower adverse reactions, to enable testing in clinical trials as an antitumor drug. The main purpose of this review is to provide a description of oncolytic mechanisms, clinical studies, combination therapies, current challenges, and future prospects of OVs.

The gasdermins, family of pore‐forming proteins, are emerging key regulators of infection, autoinflammation and antitumor immunity. Multiple studies have recently characterised their crucial roles in driving pyroptosis, a lytic pro‐inflammatory type of cell death. Additionally, gasdermins also act as key effectors of NETosis, secondary necrosis and apoptosis. In this review, we will address current understanding of the mechanisms of gasdermin activation and further describe the protective and detrimental roles of gasdermins in host defence and autoinflammatory diseases. These data suggest that gasdermins play a prominent role in innate immunity and autoinflammatory disorders, thereby providing potential new therapeutic avenues for the treatment of infection and autoimmune disease., This review summarises the latest advances in several aspects of mode of activation of gasdermins, which finally drives pyroptosis, NETosis, secondary necrotic death and apoptosis. Here, we also highlight the current understanding of gasdermin involvement in infections and autoimmunity disorders, providing a promising translational approach to the treatment of infectious and autoinflammatory diseases.

Epirubicin is a chemotherapy agent for hepatocellular carcinoma (HCC). However, the outcome of HCC patients receiving epirubicin remains unsatisfactory. Moreover, our previous study indicated that celecoxib suppresses HCC progression and liver cancer stemness. This study evaluated the potential of celecoxib to serve as a complementary therapy during epirubicin treatment. Cell proliferation, apoptosis, invasiveness, and anchorage‐independent growth were analyzed in hepatoma cells. Therapeutic efficacy was validated in rat orthotopic Novikoff hepatoma. After animal sacrifice, the antitumor mechanism of celecoxib and epirubicin combined therapy was investigated by histological analysis. Celecoxib enhanced the cytotoxic activity of epirubicin in HCC cells by promoting apoptosis. Besides, celecoxib potentiated the antineoplastic function of epirubicin in inhibiting the invasiveness and anchorage‐independent growth of HCC cells. Ultrasound monitoring showed that combined therapy was more potent than either therapy alone in perturbing HCC progression. Consistently, the size and weight of dissected HCC tissues from rats receiving combined therapy were smallest among all groups. HCC treated with combined therapy exhibited the highest prevalence of apoptotic cells, which was accompanied by reduced proliferating and angiogenic activities in tumor tissues. Moreover, the expression levels of cancer stemness markers (CD44 and CD133) and drug transporter MDR‐1 were significantly diminished in rats receiving combined therapy. Besides, celecoxib treatment increased the infiltration of cytotoxic T lymphocytes (CTLs) and reduced the number of regulatory T cells (Tregs), tumor‐associated macrophages (TAMs), and the expression of immune checkpoint PD‐L1 in HCC tissues during epirubicin therapy. Celecoxib augmented the therapeutic efficacy while modulated cancer stemness and antitumor immunity. Thus, celecoxib may serve as complementary therapy to improve the outcome of patients with advanced HCC during epirubicin treatment.

Multimodality therapies are used to manage patients with hepatocellular carcinoma (HCC), although advanced HCC is incurable. Oncolytic virus therapy is probably the next major breakthrough in cancer treatment. The third-generation oncolytic herpes simplex virus type 1 (HSV-1) T-01 kills tumor cells without damaging the surrounding normal tissues. Here we investigated the antitumor effects of T-01 on HCC and the host's immune response to HCC cells. The cytopathic activities of T-01 were tested in 14 human and 1 murine hepatoma cell line in vitro. In various mouse xenograft models, HuH-7, KYN-2, PLC/PRF/5 and HepG2 human cells and Hepa1-6 murine cells were used to investigate the in vivo efficacy of T-01. T-01 was cytotoxic to 13 cell lines (in vitro). In mouse xenograft models of subcutaneous, orthotopic and peritoneal tumor metastasis in athymic mice (BALB/c nu/nu), the growth of tumors formed by the human HCC cell lines and hepatoblastoma cell line was inhibited by T-01 compared with that of mock-inoculated tumors. In a bilateral Hepa1-6 subcutaneous tumor model in C57BL/6 mice, the growth of tumors inoculated with T-01 was inhibited, as was the case for contralateral tumors. T-01 also significantly reduced tumor growth. T-01 infection significantly enhanced antitumor efficacy via T cell-mediated immune responses. Results demonstrate that a third-generation oncolytic HSV-1 may serve as a novel treatment for patients with HCC.

The combination of immunotherapy with other forms of treatment is an emerging strategy for boosting antitumor responses. By combining multiple modes of action, these combinatorial therapies can improve clinical outcomes through unique synergisms. Here, a microrobot-based strategy that integrates tumor tissue disruption with biological stimulation is shown for cancer immunotherapy. The microrobot is fabricated by loading bacterial outer membrane vesicles onto a self-propelling micromotor, which can react with water to generate a propulsion force. When administered intratumorally to a solid tumor, the disruption of the local tumor tissue coupled with the delivery of an immunostimulatory payload leads to complete tumor regression. Additionally, treatment of the primary tumor results in the simultaneous education of the host immune system, enabling it to control the growth of distant tumors. Overall, this work introduces a distinct application of microrobots in cancer immunotherapy and offers an attractive strategy for amplifying cancer treatment efficacy when combined with conventional therapies.

Key Clinical Message The mechanism of abscopal effect is becoming clear by the progress of cancer immunology. A 54‐year‐old male with recurrent gastric cancer presented an abscopal effect after radiotherapy with concurrent adoptive T‐cell immunotherapy (immunoradiotherapy). Immunoradiotherapy has potential to induce abscopal effect by strengthening systemic antitumor immunity even in recurrent cancer.

γδ T cells are a small population of mostly tissue‐resident lymphocytes, with both innate and adaptive properties. These unique features make them particularly attractive candidates for the development of new cellular therapy targeted against tumor development. Nevertheless, γδ T cells may play dual roles in cancer, promoting cancer development on the one hand, while participating in antitumor immunity on the other hand. In mice, γδ T‐cell subsets preferentially produce IL‐17 or IFN‐γ. While antitumor functions of murine γδ T cells can be attributed to IFN‐γ+ γδ T cells, recent studies have implicated IL‐17+ γδ T cells in tumor growth and metastasis. However, in humans, IL‐17‐producing γδ T cells are rare and most studies have attributed a protective role to γδ T cells against cancer. In this review, we will present the current knowledge and most recent findings on γδ T‐cell functions in mouse models of tumor development and human cancers. We will also discuss their potential as cellular immunotherapy against cancer.

Currently, radiotherapy (RT) is the main method for cancer treatment. However, the hypoxic environment of solid tumors is likely to cause resistance or failure of RT. Moreover, high-dose radiation may cause side effects to surrounding normal tissues. In this study, a new type of nanozyme is developed by doping Mn (II) ions into Ag2 Se quantum dots (QDs) emitting in the second near-infrared window (NIR-II, 1000-1700 nm). Through the catalysis of Mn (II) ions, the nanozymes can trigger the rapid decomposition of H2 O2 and produce O2 . Conjugated with tumor-targeting arginine-glycine-aspartate (RGD) tripeptides and polyethylene glycol (PEG) molecules, the nanozymes are then constructed into in vivo nanoprobes for NIR-II imaging-guided RT of tumors. Owing to the radiosensitive activity of the element Ag, the nanoprobes can promote radiation energy deposition. The specific tumor-targeting and NIR-II emitting abilities of the nanoprobes facilitate the precise tumor localization, which enables precise RT with low side effects. Moreover, their ultra-stability in the living body ensures that the nanoprobes continuously produce oxygen and relieve the hypoxia of tumors to enhance RT efficacy. Guided by real-time and high-clarity imaging, the nanoprobe-mediated RT promotes anti-tumor immunity, which significantly inhibits the growth of tumors or even cures them completely.

Cancer arises from a deregulation of both intracellular and intercellular networks that maintain system homeostasis. Identifying the architecture of these networks and how they are changed in cancer is a pre-requisite for designing drugs to restore homeostasis. Since intercellular networks only appear in intact systems, it is difficult to identify how these networks become altered in human cancer using many of the common experimental models. To overcome this, we used the diversity in normal and malignant human tissue samples from the Cancer Genome Atlas (TCGA) database of human breast cancer to identify the topology associated with intercellular networks in vivo. To improve the underlying biological signals, we constructed Bayesian networks using metagene constructs, which represented groups of genes that are concomitantly associated with different immune and cancer states. We also used bootstrap resampling to establish the significance associated with the inferred networks. In short, we found opposing relationships between cell proliferation and epithelial-to-mesenchymal transformation (EMT) with regards to macrophage polarization. These results were consistent across multiple carcinomas in that proliferation was associated with a type 1 cell-mediated anti-tumor immune response and EMT was associated with a pro-tumor anti-inflammatory response. To address the identifiability of these networks from other datasets, we could identify the relationship between EMT and macrophage polarization with fewer samples when the Bayesian network was generated from malignant samples alone. However, the relationship between proliferation and macrophage polarization was identified with fewer samples when the samples were taken from a combination of the normal and malignant samples. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:470-479, 2016.

Currently, cell membrane is always utilized for the construction of biomimetic nanoparticles. By contrast, mimicking the intracellular activity seems more meaningful. Inspired by the specific killing mechanism of deoxy-hemoglobin (Hb) dependent drug (RRx-001) in hypoxic red blood cells (RBC), this work aims to develop an inner and outer RBC-biomimetic antitumor nanoplatform that replicates both membrane surface properties and intracellularly certain therapeutic mechanisms of RRx-001 in hypoxic RBC. Herein, RRx-001 and Hb are introduced into RBC membrane camouflaged TiO2 nanoparticles. Upon arrival at hypoxic tumor microenvironment (TME), the biomimetic nanoplatform (R@HTR) is activated and triggers a series of reactions to generate reactive nitrogen species (RNS). More importantly, the potent antitumor immunity and immunomodulatory function of RNS in TME are demonstrated. Such an idea would transfer the battlefield of RRx-001 from hypoxic RBC to hypoxic TME, enhancing its combat capability. As a proof of concept, this biomimetic nanoreactor of RNS exhibits efficient tumor regression and metastasis prevention. The battlefield transfer strategy would not only present meaningful insights for immunotherapy, but also realize substantial breakthroughs in biomimetic nanotechnology.

Type I interferons (IFN-Is) are a family of cytokines that exert direct antiviral effects and regulate innate and adaptive immune responses through direct and indirect mechanisms. It is generally believed that IFN-Is repress tumor development via restricting tumor proliferation and inducing antitumor immune responses. However, recent emerging evidence suggests that IFN-Is play a dual role in antitumor immunity. That is, in the early stage of tumorigenesis, IFN-Is promote the antitumor immune response by enhancing antigen presentation in antigen-presenting cells and activating CD8+ T cells. However, in the late stage of tumor progression, persistent expression of IFN-Is induces the expression of immunosuppressive factors (PD-L1, IDO, and IL-10) on the surface of dendritic cells and other bone marrow cells and inhibits their antitumor immunity. This review outlines these dual functions of IFN-Is in antitumor immunity and elucidates the involved mechanisms, as well as their applications in tumor therapy.

Delivery of antigen in particulate form using either synthetic or natural particles induces stronger immunity than soluble forms of the antigen. Among naturally occurring particles, virus-like particles (VLPs) have been genetically engineered to express tumor-associated antigens (TAAs) and have shown to induce strong TAA-specific immune responses due to their nano-particulate size and ability to bind and activate antigen-presenting cells. In this report, we demonstrate that influenza VLPs can be modified by a protein transfer technology to express TAAs for induction of effective antitumor immune responses. We converted the breast cancer HER-2 antigen to a glycosylphosphatidylinositol (GPI)-anchored form and incorporated GPI-HER-2 onto VLPs by a rapid protein transfer process. Expression levels on VLPs depended on the GPI-HER-2 concentration added during protein transfer. Vaccination of mice with protein transferred GPI-HER-2-VLPs induced a strong Th1 and Th2-type anti-HER-2 antibody response and protected mice against a HER-2-expressing tumor challenge. Soluble form of GPI-HER-2 induced only a weak Th2 response under similar conditions. These results suggest that influenza VLPs can be enriched with TAAs by protein transfer to develop effective VLP-based subunit vaccines against cancer without chemical or genetic modifications and thus preserve the immune stimulating properties of VLPs for easier production of antigen-specific therapeutic cancer vaccines.

Ovarian cancer is a difficult-to-treat cancer with a 5-year survival rate of only approximate to 45%, due to late diagnosis and therapy resistance. In need of new therapeutic approaches, induction of intercellular adhesion molecule (ICAM)-1 expression might be of interest, since the expression of ICAM-1 is lower in ovarian cancer cells compared with healthy ovarian cells and correlated with decreased tumorigenicity. Whereas ICAM-1 expression on tumor cells is of importance for attracting immune cells, ICAM-1 might also induce tumorigenicity and chemoresistance. In ovarian cancer, such a role of ICAM-1 is unclear. Here, we investigated whether ICAM-1 has a cell-biological role by bidirectional modulation of ICAM-1 expression using ICAM-targeting artificial transcription factors. For a panel of ovarian cancer cells, tumor growth and cisplatin sensitivity were evaluated. Induction of ICAM-1 expression (ranging from 3- to 228-fold on mRNA level and 1.7- to 108-fold on protein level) resulted in indications of decreased ovarian cancer cell growth and reduced cisplatin sensitivity. Repression ranged from 48 to 94% on mRNA level and 47 to 91% on protein level. This study shows that, next to its established immunogenic role, ICAM-1 affects cell biological behavior of ovarian cancer cells and, importantly, that reexpression by artificial transcription factors represents a powerful approach for functional validation of genes epigenetically silenced in cancer, such as ICAM-1.