Combined approach for predicting the efficacy of nivolumab in head and neck carcinoma by tissue and soluble expressions of PD-L1 and PD-L2.

BACKGROUND: Predictive biomarkers for nivolumab in recurrent or metastatic head and neck squamous cell carcinoma (RMHNSCC) have not yet been established. METHODS: The tumor proportion score (TPS), combined positive score (CPS), and soluble forms of programmed cell death ligand-1 (PD-L1) and programmed cell death ligand-2 (PD-L2) were retrospectively analyzed in patients with RMHNSCC treated with nivolumab. RESULTS: The positivity rates for TPS (PD-L1), CPS (PD-L1), TPS (PD-L2), and CPS (PD-L2) were 73.8%, 78.2%, 56.4%, and 78.2%, respectively. Patients with high TPS (PD-L1), CPS (PD-L1), or CPS (PD-L1 and PD-L2) showed significantly prolonged progression-free survival. Favorable overall survival was associated with high CPS (PD-L1 and PD-L2) and low soluble PD-L1 and PD-L2 levels. The expressions of tissue and soluble PD-L1/2 were not correlated. CONCLUSIONS: Our study revealed that compared to PD-L1 expression alone, dual expression of PD-L1 and PD-L2 in tissue or soluble form could be feasible biomarkers in patients with RMHNSCC who received nivolumab.

Immunotherapy targeting tumor-associated antigen in a mouse model of head and neck cancer.

BACKGROUND: The identification of epitope peptides from tumor-associated antigens (TAAs) is informative for developing tumor-specific immunotherapy. However, only a few epitopes have been detected in mouse TAAs of head and neck cancer (HNSCC). METHODS: Novel mouse c-Met-derived T-cell epitopes were predicted by computer-based algorithms. Mouse HNSCC cell line-bearing mice were treated with a c-Met peptide vaccine. The effects of CD8 and/or CD4 T-cell depletion, and vaccine combination with immune checkpoint inhibitors (ICIs) were evaluated. Tumor re-inoculation was performed to assess T-cell memory. RESULTS: We identified c-Met-derived short and long epitopes that elicited c-Met-reactive antitumor CD8 and/or CD4 T-cell responses. Vaccination using these peptides showed remarkable antitumor responses via T cells in which ICIs were not required. The c-Met peptide-vaccinated mice rejected the re-inoculated tumors. CONCLUSIONS: We demonstrated that novel c-Met peptide vaccines can induce antitumor T-cell response, and could be a potent immunotherapy in a syngeneic mouse HNSCC model.

Soluble CD27 as a predictive biomarker for intra-tumoral CD70/CD27 interaction in nasopharyngeal carcinoma.

In CD70-expressing tumors, the interaction of CD70 on tumor cells with its lymphocyte receptor, CD27, is thought to play a role in immunosuppression in the tumor microenvironment and elevated serum levels of soluble CD27 (sCD27). Previous studies showed that CD70 is expressed in nasopharyngeal carcinoma (NPC), an Epstein-Barr virus (EBV)-related malignancy. However, the association between intratumoral CD70/CD27 expression and serum levels of sCD27 in NPC remains unclear. In the present study, we show that CD70 is primarily expressed by tumor cells in NPC and that CD27-positive lymphocytes infiltrate around tumor cells. NPC patients with CD27-positive lymphocytes had significantly better prognosis than patients lacking these cells. In addition, high CD70 expression by tumor cells tended to be correlated with shorter survival in NPC patients with CD27-positive lymphocytes. Serum sCD27 levels were significantly increased in patients with NPC and provided good diagnostic accuracy for discriminating patients from healthy individuals. The concentration of serum sCD27 in patients with CD70-positive NPC with CD27-positive lymphocytes was significantly higher than in patients with tumors negative for CD70 and/or CD27, indicating that the intratumoral CD70/CD27 interaction boosts the release of sCD27. Furthermore, positive expression of CD70 by NPC cells was significantly correlated with EBV infection. Our results suggest that CD70/CD27-targeted immunotherapies may be promising treatment options and that sCD27 may become an essential tool for evaluating the applicability of these therapies by predicting the intratumoral CD70/CD27 interaction in NPC.

Cerebral Infarction as a Rare Adverse Event of Immune Checkpoint Inhibitors in Patients With Head and Neck Squamous Cell Carcinoma: A Case Series.

Immune checkpoint inhibitors (ICIs) are a novel treatment option for treating head and neck squamous cell carcinoma (HNSCC). Among the immune-related adverse effects, cerebral infarction (CI) is a rare but fatal complication, and it has been reported in various cancers, except HNSCC. Herein, we describe three cases of patients diagnosed with HNSCC who experienced CI following ICI treatment. In addition, we conducted a comprehensive literature review on ICI-related thrombosis. Three patients with recurrent HNSCC were treated with nivolumab. Two patients had a history of CI, or heart disease, and were concurrently prescribed antithrombotic medications during nivolumab treatment. The number of nivolumab administrations varied from 1-25 before the onset of CI. All patients experienced worsening of neurological symptoms due to CI, irrespective of antithrombotic treatment, and they ultimately succumbed to the disease within 16-222 days following their initial ICI administration. ICIs may cause thromboembolisms, leading to CI. Based on our review of the literature, a history of thromboembolism or heart disease could be a risk factor for ICI-related thrombosis.

An Otogenic Variant of Lemierre's Syndrome Caused by Trueperella bernardiae: A Case Report and Literature Review.

Upper airway infections caused by anaerobic bacteria, including pharyngitis and tonsillitis, are a common cause of septic thrombosis (Lemierre's syndrome). Although otitis media rarely progresses to systemic infection, an abscess surrounding the middle ear can affect the central nervous system. Trueperella bernardiae was originally considered a non-pathogenic aerobic bacterium but has subsequently been reported to cause bacteremia and brain abscesses. Here, we report a case of otitis media caused by T. bernardiae complicated by meningitis, subdural empyema, and septic pulmonary emboli in an immunocompetent patient.

Treatment outcomes of alternating chemoradiotherapy for nasopharyngeal carcinoma: a single-center safety and efficacy study

Abstract Objective To evaluate the efficacy and safety of Alternating Chemoradiotherapy (ACRT) using cisplatin and 5-Fluorouracil (5-FU) in patients with nasopharyngeal carcinoma. Methods This was a retrospective study in which patients' clinical records were reviewed to identify patients with a new diagnosis of nasopharyngeal carcinoma at our institution between January 2005 and January 2019. Thirty-seven eligible patients were identified; of these, the clinical details of 27 patients treated with ACRT were evaluated. Patient outcomes, including overall survival and progression-free survival, and adverse events were assessed. Results Of these initial 37 patients, 1, 10, 13, 10, and 3 were staged as I, II, III, IVA, and IVB, respectively, as defined by the 8th edition of the TNM classification system. Twenty-seven patients received ACRT comprising sequential administration of chemotherapy, radiotherapy (wide field), chemotherapy, radiotherapy (shrinking field), and chemotherapy. The 5-year overall survival and progression-free survival rates were 83.7% and 88.9%, respectively. Treatment compliance was 93%, which is comparable to that of previous reports. Conclusion ACRT using cisplating and 5-fluorouracil was well tolerated with acceptable efficacy. Level of Evidence IVa

Brachyury-targeted immunotherapy combined with gemcitabine against head and neck cancer.

Brachyury is a transcription factor belonging to the T-box gene family and is involved in the posterior formation of the mesoderm and differentiation of chordates. As the overexpression of Brachyury is a poor prognostic factor in a variety of cancers, the establishment of Brachyury-targeted therapy would be beneficial for the treatment of aggressive tumors. Because transcription factors are difficult to treat with a therapeutic antibody, peptide vaccines are a feasible approach for targeting Brachyury. In this study, we identified Brachyury-derived epitopes that elicit antigen-specific and tumor-reactive CD4+ T cells that directly kill tumors. T cells recognizing Brachyury epitopes were present in patients with head and neck squamous cell carcinoma. Next, we focused on gemcitabine (GEM) as an immunoadjuvant to augment the efficacy of antitumor responses by T cells. Interestingly, GEM upregulated HLA class I and HLA-DR expression in tumor, followed by the upregulation of anti-tumor T cell responses. As tumoral PD-L1 expression was also augmented by GEM, PD-1/PD-L1 blockade and GEM synergistically enhanced the tumor-reactivity of Brachyury-reactive T cells. The synergy between the PD-1/PD-L1 blockade and GEM was also confirmed in a mouse model of head and neck squamous cell carcinoma. These results suggest that the combined treatment of Brachyury peptide with GEM and immune checkpoint blockade could be a promising immunotherapy against head and neck cancer.

Treatment outcomes of sialendoscopy for submandibular gland sialolithiasis.

OBJECTIVE: Sialendoscopy is a procedure used to remove salivary stones intraorally using a sialendoscope. In this study, we identified treatment outcomes of sialendoscopic surgery and identified predictive factors for successful stone removal by sialendoscopy alone. METHODS: We assembled the medical records of 144 patients who underwent sialendoscopic surgery for submandibular gland sialolithiasis at the Department of Otolaryngology-Head and Neck Surgery, Asahikawa Medical University, from October 2010 to November 2021, and collected patient backgrounds, medical condition, perioperative factors including operation method and complications, postoperative course, and stone constituents from a clinical laboratory testing company. RESULTS: Submandibular gland stones were successfully removed using sialendoscopy in 58 patients (40%). In multivariate analysis, location, major axis, and mobility of the stones were independent factors for successful removal. In receiver operating characteristic analysis, <7.5 mm of a major axis may be used as a measuring standard for successful removal. Removal of parenchymal stones is prone to involve prolonged operation times, increased postoperative complications, and development of retained stones. The stones mainly consisted of calcium phosphate and protein, with content percentages ranging from 0 to 98% (median 37%) and from 0 to 100% (median 63%), respectively. The percentage of calcium phosphate was negatively correlated with the number of floating stones and successful stone removal. CONCLUSION: Sialendoscopy is an aesthetically attractive treatment for sialolithiasis that avoids cervical incisions. The present results showed not only known but also new predictive factors for the successful removal of stones (<7.5 mm) and percentage of calcium phosphate. Moreover, our results suggest that careful consideration is required regarding the indication of sialendoscopic surgery in patients with parenchymal stones.

Expression of soluble CD27 in extranodal natural killer/T-cell lymphoma, nasal type: potential as a biomarker for diagnosis and CD27/CD70-targeted therapy.

The engagement of CD27 on lymphocytes with its ligand, CD70, on tumors is believed to mediate tumor immune evasion and the elevation of serum soluble CD27 (sCD27) levels in patients with CD70-positive malignancies. We previously showed that CD70 is expressed in extranodal natural killer/T-cell lymphoma, nasal type (ENKL), an Epstein-Barr virus (EBV)-related malignancy. However, little is known about serum sCD27 expression and its association with the clinical characteristics of, and the CD27/CD70 interaction in, ENKL. In the present study, we show that serum sCD27 is significantly elevated in the sera of patients with ENKL. The levels of serum sCD27 provided excellent diagnostic accuracy for discriminating patients with ENKL from healthy subjects, correlated positively with the levels of other diagnostic markers (lactate dehydrogenase, soluble interleukin-2 receptor, and EBV-DNA), and decreased significantly following treatment. Elevated serum sCD27 levels also correlated significantly with advanced clinical stage and tended to correspond with shorter survival, in patients with ENKL. Immunohistochemistry indicated that CD27-positive tumor-infiltrating immune cells exist adjacent to CD70-positive lymphoma cells. In addition, serum sCD27 levels in patients with CD70-positive ENKL were significantly higher than those in patients with CD70-negative ENKL, suggesting that the intra-tumoral CD27/CD70 interaction boosts the release of sCD27 in serum. Furthermore, the EBV-encoded oncoprotein latent membrane protein 1 upregulated CD70 expression in ENKL cells. Our results suggest that sCD27 may serve as a novel diagnostic biomarker and also may serve as a tool for evaluating the applicability of CD27/CD70-targeted therapies by predicting intra-tumoral CD70 expression and CD27/CD70 interaction in ENKL.

Treatment outcomes of alternating chemoradiotherapy for nasopharyngeal carcinoma: a single-center safety and efficacy study.

OBJECTIVE: To evaluate the efficacy and safety of Alternating Chemoradiotherapy (ACRT) using cisplatin and 5-Fluorouracil (5-FU) in patients with nasopharyngeal carcinoma. METHODS: This was a retrospective study in which patients' clinical records were reviewed to identify patients with a new diagnosis of nasopharyngeal carcinoma at our institution between January 2005 and January 2019. Thirty-seven eligible patients were identified; of these, the clinical details of 27 patients treated with ACRT were evaluated. Patient outcomes, including overall survival and progression-free survival, and adverse events were assessed. RESULTS: Of these initial 37 patients, 1, 10, 13, 10, and 3 were staged as I, II, III, IVA, and IVB, respectively, as defined by the 8th edition of the TNM classification system. Twenty-seven patients received ACRT comprising sequential administration of chemotherapy, radiotherapy (wide field), chemotherapy, radiotherapy (shrinking field), and chemotherapy. The 5-year overall survival and progression-free survival rates were 83.7% and 88.9%, respectively. Treatment compliance was 93%, which is comparable to that of previous reports. CONCLUSION: ACRT using cisplating and 5-fluorouracil was well tolerated with acceptable efficacy. LEVEL OF EVIDENCE: IVa.

Mitogen-activated protein kinase inhibition augments the T cell response against HOXB7-expressing tumor through human leukocyte antigen upregulation.

Homeobox B7 (HOXB7) is a master regulatory gene that regulates cell proliferation and activates oncogenic pathways. Overexpression of HOXB7 correlates with aggressive behavior and poor prognosis in patients with cancer. However, the expression and role of HOXB7 in head and neck squamous cell carcinoma (HNSCC) remain unclear. In this study, we observed that most samples from patients with oropharyngeal cancer and HNSCC expressed HOXB7. As no direct inhibitor has been reported, we identified a potent peptide epitope to target HOXB7-expressing tumors through immune cells. A novel HOXB7-derived peptide epitope (HOXB78-25 ) elicited antigen-specific and tumor-reactive promiscuous CD4+ T cell responses. These CD4+ T cells produced γ-interferon (IFN-γ) and had the direct ability to kill tumors through granzyme B. Notably, downregulation of HOXB7 using siRNA enhanced human leukocyte antigen class II expression on tumor cells by decreasing the phosphorylation of MAPK. Mitogen-activated protein kinase inhibition augmented IFN-γ production by HOXB7-reactive CD4+ T cell responses without decreasing the expression of HOXB7. These results suggest that combining HOXB7 peptide-based vaccine with MAPK inhibitors could be an effective immunological strategy for cancer treatment.

Central-part laryngectomy after laryngotracheal separation to manage pharyngocutaneous fistula: A case report and retrospective analysis of 12 cases.

A 15-year-old girl presented with a 3-year-history of continuous outflow of saliva from a pharyngocutaneous fistula, located at 5 mm superior to her tracheal stoma. She was diagnosed with Miller-Dieker syndrome at birth. At 2 years of age, pediatric surgeons at our institution carried out laryngotracheal separation to prevent aspiration pneumonia. At the age of 12 years, she developed continuous saliva discharge from the fistula. We performed central-part laryngectomy and resection of the pharyngocutaneous fistula, which relieved her from the continuous saliva discharge. Central-part laryngectomy is less invasive and easier to perform than total laryngectomy. We hereby present a case and retrospective analysis of 12 patients, who underwent central-part laryngectomy.

A tumor metastasis-associated molecule TWIST1 is a favorable target for cancer immunotherapy due to its immunogenicity.

Although neoantigens are one of the most favorable targets in cancer immunotherapy, it is less versatile and costly to apply neoantigen-derived cancer vaccines to patients due to individual variation. It is, therefore, important to find highly immunogenic antigens between tumor-specific or associated antigens that are shared among patients. Considering the cancer immunoediting theory, immunogenic tumor cells cannot survive in the early phase of tumor progression including two processes: elimination and equilibrium. We hypothesized that highly immunogenic molecules are allowed to be expressed in tumor cells after an immune suppressive tumor microenvironment was established, if these molecules contribute to tumor survival. In the current study, we focused on TWIST1 as a candidate for highly immunogenic antigens because it is upregulated in tumor cells under hypoxia and promotes tumor metastasis, which is observed in the late phase of tumor progression. We demonstrated that TWIST1 had an immunogenic peptide sequence TWIST1140-162 , which effectively activated TWIST1-specific CD4+ T-cells. In a short-term culture system, we detected more TWIST1-specific responses in breast cancer patients compared with in healthy donors. Vaccination with the TWIST1 peptide also showed efficient expansion of TWIST1-reactive HTLs in humanized mice. These findings indicate that TWIST1 is a highly immunogenic shared antigen and a favorable target for cancer immunotherapy.

IL-2 complex recovers steroid-induced inhibition in immunochemotherapy for head and neck cancer.

BACKGROUND: A combination therapy with immune checkpoint inhibitors (ICIs) and platinum-based chemotherapy has become the first-line treatment for recurrent or metastatic head and neck squamous carcinoma (HNSCC). Although steroids are often used as anti-emetic medications during chemotherapy, their adverse effects on immune-combined chemotherapy are unclear in HNSCC. METHODS: The effects of dexamethasone on tumor growth and immune cell population were evaluated in a mouse HNSCC model treated with PD-1 blockade combined with cisplatin. The effect of various doses of dexamethasone on cell proliferation, survival, surface markers, IFN-γ production, and antitumor effects in antigen-specific T cells was examined in vitro. The recovery of T cell dysfunction by IL-2 was assessed in vitro and in vivo. RESULTS: In a mouse HNSCC model, dexamethasone showed limited antitumor effects on immunochemotherapy. Dexamethasone decreased the number of T cells and inhibited T cell differentiation into effector and central memory T cells. In the in vitro assessment, dexamethasone induced cell death, limited proliferation, and reduced the reactivity against HNSCC cell lines of antigen-specific T cells in a dose-dependent manner. The expression of inhibitory receptors on T cells was not affected by steroids. This inhibition was recovered by IL-2 and IL-2/anti-IL-2 complexes (IL-2 Cx) in vitro and in vivo, respectively. CONCLUSION: Our preclinical data indicate that dexamethasone diminishes the antitumor effects of immunochemotherapy in patients with HNSCC. IL-2 Cx recovered the inhibition of antitumor immunity by steroids and might be a potent immune adjuvant for patients who require steroids during PD-1 blockade and chemotherapy.

Immunomodulation via FGFR inhibition augments FGFR1 targeting T-cell based antitumor immunotherapy for head and neck squamous cell carcinoma.

Fibroblast growth factor receptor 1 (FGFR1) is overexpressed in multiple types of solid tumors, including head and neck squamous cell carcinoma (HNSCC). Being associated with poor prognosis, FGFR1 is a potential therapeutic target for aggressive tumors. T cell-based cancer immunotherapy has played a central role in novel cancer treatments. However, the potential of antitumor immunotherapy targeting FGFR1 has not been investigated. Here, we showed that FGFR-tyrosine kinase inhibitors (TKIs) augmented antitumor effects of immune checkpoint inhibitors in an HNSCC mouse model and upregulated tumoral MHC class I and MHC class II expression in vivo and in vitro. This upregulation was associated with the mitogen-activated protein kinase signaling pathway, which is a crucial pathway for cancer development through FGFR signaling. Moreover, we identified an FGFR1-derived peptide epitope (FGFR1305-319) that could elicit antigen-reactive and multiple HLA-restricted CD4+ T cell responses. These T cells showed direct cytotoxicity against tumor cells that expressed FGFR1. Notably, FGFR-TKIs augmented antitumor effects of FGFR1-reactive T cells against human HNSCC cells. These results indicate that the combination of FGFR-TKIs with immunotherapy, such as an FGFR1-targeting peptide vaccine or immune checkpoint inhibitor, could be a novel and robust immunologic approach for treating patients with FGFR1-expressing cancer cells.

CD47 blockade enhances the efficacy of intratumoral STING-targeting therapy by activating phagocytes.

Activation of STING signaling plays an important role in anti-tumor immunity, and we previously reported the anti-tumor effects of STING through accumulation of M1-like macrophages in tumor tissue treated with a STING agonist. However, myeloid cells express SIRPα, an inhibitory receptor for phagocytosis, and its receptor, CD47, is overexpressed in various cancer types. Based on our findings that breast cancer patients with highly expressed CD47 have poor survival, we evaluated the therapeutic efficacy and underlying mechanisms of combination therapy with the STING ligand cGAMP and an antagonistic anti-CD47 mAb using E0771 mouse breast cancer cells. Anti-CD47 mAb monotherapy did not suppress tumor growth in our setting, whereas cGAMP and anti-CD47 mAb combination therapy inhibited tumor growth. The combination therapy enhanced phagocytosis of tumor cells and induced systemic anti-tumor immune responses, which rely on STING and type I IFN signaling. Taken together, our findings indicate that coadministration of cGAMP and an antagonistic anti-CD47 mAb may be promising for effective cancer immunotherapy.

Transient IL-33 upregulation in neonatal mouse lung promotes acute but not chronic type 2 immune responses induced by allergen later in life.

Early life respiratory insults, such as viral infections or hyperoxia, often increase asthma susceptibility later in life. The mechanisms underlying this increased susceptibility are not fully understood. IL-33 has been shown to be critically involved in allergic airway diseases. IL-33 expression in the neonatal lung can be increased by various respiratory insults associated with asthma development. Therefore, we investigated whether and how early life increases in IL-33 impact allergic airway responses later in life. Using a novel IL-33 transgenic mouse model, in which full-length IL-33 was inducible overexpressed in lung epithelial cells, we transiently upregulated lung IL-33 expression in neonatal mice for one week. After resting for 4-6 weeks, mice were intranasally exposed to a single-dose of recombinant IL-33 or the airborne allergen Alternaria. Alternatively, mice were exposed to Alternaria and ovalbumin multiple times for one month. We found that a transient increase in IL-33 expression during the neonatal period promoted IL-5 and IL-13 production when mice were later exposed to a single-dose of IL-33 or Alternaria in adulthood. However, increased IL-33 expression during the neonatal period did not affect airway inflammation, type 2 cytokine production, lung mucus production, or antigen-specific antibody responses when adult mice were exposed to Alternaria and ovalbumin multiple times. These results suggest that transient increased IL-33 expression early in life may have differential effects on allergic airway responses in later life, preferentially affecting allergen-induced acute type 2 cytokine production.

A stealth antigen SPESP1, which is epigenetically silenced in tumors, is a suitable target for cancer immunotherapy.

Recent studies have revealed that tumor cells decrease their immunogenicity by epigenetically repressing the expression of highly immunogenic antigens to survive in immunocompetent hosts. We hypothesized that these epigenetically hidden "stealth" antigens should be favorable targets for cancer immunotherapy due to their high immunogenicity. To identify these stealth antigens, we treated human lung cell line A549 with DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine (5Aza) and its prodrug guadecitabine for 3 d in vitro and screened it using cDNA microarray analysis. We found that the gene encoding sperm equatorial segment protein 1 (SPESP1) was re-expressed in cell lines including solid tumors and leukemias treated with 5Aza, although SPESP1 was not detected in untreated tumor cell lines. Using normal human tissue cDNA panels, we demonstrated that SPESP1 was not detected in normal human tissue except for testis and placenta. Moreover, we found using immunohistochemistry SPESP1 re-expression in xenografts in BALB/c-nu/nu mice that received 5Aza treatment. To assess the antigenicity of SPESP1, we stimulated human CD4+ T-cells with a SPESP1-derived peptide designed using a computer algorithm. After repetitive stimulation, SPESP1-specific helper T-cells were obtained; these cells produced interferon-γ against HLA-matched tumor cell lines treated with 5Aza. We also detected SPESP1 expression in freshly collected tumor cells derived from patients with acute myeloid leukemia or lung cancer. In conclusion, SPESP1 can be classified as a stealth antigen, a molecule encoded by a gene that is epigenetically silenced in tumor cells but serves as a highly immunogenic antigen suitable for cancer immunotherapy.

Interruption of MDM2 signaling augments MDM2-targeted T cell-based antitumor immunotherapy through antigen-presenting machinery.

Identification of immunogenic tumor antigens, their corresponding T cell epitopes and the selection of effective adjuvants are prerequisites for developing effective cancer immunotherapies such as therapeutic vaccines. Murine double minute 2 (MDM2) is an E3 ubiquitin-protein ligase that negatively regulates tumor suppressor p53. Because MDM2 overexpression serves as a poor prognosis factor in various types of tumors, it would be beneficial to develop MDM2-targeted cancer vaccines. In this report, we identified an MDM2-derived peptide epitope (MDM232-46) that elicited antigen-specific and tumor-reactive CD4+ T cell responses. These CD4+ T cells directly killed tumor cells via granzyme B. MDM2 is expressed in head and neck cancer patients with poor prognosis, and the T cells that recognize this MDM2 peptide were present in these patients. Notably, Nutlin-3 (MDM2-p53 blocker), inhibited tumor cell proliferation, was shown to augment antitumor T cell responses by increasing MDM2 expression, HLA-class I and HLA-DR through class II transactivator (CIITA). These results suggest that the use of this MDM2 peptide as a therapeutic vaccine combined with MDM2 inhibitors could represent an effective immunologic strategy to treat cancer.

A critical role of STING-triggered tumor-migrating neutrophils for anti-tumor effect of intratumoral cGAMP treatment.

Stimulator of interferon genes (STING) contributes to anti-tumor immunity by activating antigen-presenting cells and inducing mobilization of tumor-specific T cells. A role for tumor-migrating neutrophils in the anti-tumor effect of STING-activating therapy has not been defined. We used mouse tumor transplantation models for assessing neutrophil migration into the tumor triggered by intratumoral treatment with STING agonist, 2'3'-cyclic guanosine monophosphate-adenosine monophosphate (cGAMP). Intratumoral STING activation with cGAMP enhanced neutrophil migration into the tumor in an NF-κB/CXCL1/2-dependent manner. Blocking the neutrophil migration by anti-CXCR2 monoclonal antibody impaired T cell activation in tumor-draining lymph nodes (dLNs) and efficacy of intratumoral cGAMP treatment. Moreover, the intratumoral cGAMP treatment did not show any anti-tumor effect in type I interferon (IFN) signal-impaired mice in spite of enhanced neutrophil accumulation in the tumor. These results suggest that both neutrophil migration and type I interferon (IFN) induction by intratumoral cGAMP treatment were critical for T-cell activation of dLNs and the anti-tumor effect. In addition, we also performed in vitro analysis showing enhanced cytotoxicity of neutrophils by IFN-ß1. Extrinsic STING activation triggers anti-tumor immune responses by recruiting and activating neutrophils in the tumor via two signaling pathways, CXCL1/2 and type I IFNs.