Progressive changes in the protein expression profile of alveolar septa in early-stage lung adenocarcinoma

BACKGROUND

Adenocarcinomas show a stepwise progression from atypical adenomatous hyperplasia (AAH) through adenocarcinoma in situ (AIS) to invasive adenocarcinoma (IA). Immunoglobulin superfamily containing leucine-rich repeat (ISLR) is a marker of tumor-restraining cancer-associated fibroblasts (CAFs), which are distinct from conventional, strongly α-smooth muscle actin (αSMA)-positive CAFs. Fibroblast activation protein (FAP) has been focused on as a potential therapeutic and diagnostic target of CAFs.

METHODS

We investigated the changes in protein expression during adenocarcinoma progression in the pre-existing alveolar septa by assessing ISLR, αSMA, and FAP expression in normal lung, AAH, AIS, and IA. Fourteen AAH, seventeen AIS, and twenty IA lesions were identified and randomly sampled. Immunohistochemical analysis was performed to evaluate cancer-associated changes and FAP expression in the pre-existing alveolar structures.

RESULTS

Normal alveolar septa expressed ISLR. The ISLR level in the alveolar septa decreased in AAH and AIS tissues when compared with that in normal lung tissue. The αSMA-positive area gradually increased from the adjacent lung tissue (13.3% ± 15%) to AIS (87.7% ± 14%), through AAH (70.2% ± 21%). Moreover, the FAP-positive area gradually increased from AAH (1.69% ± 1.4%) to IA (11.8% ± 7.1%), through AIS (6.11% ± 5.3%). Protein expression changes are a feature of CAFs in the pre-existing alveolar septa that begin in AAH. These changes gradually progressed from AAH to IA through AIS.

CONCLUSIONS

FAP-positive fibroblasts may contribute to tumor stroma formation in early-stage lung adenocarcinoma, and this could influence the development of therapeutic strategies targeting FAP-positive CAFs for disrupting extracellular matrix formation.

Potent CTLs can be induced against tumor cells in an environment of lower levels of systemic MFG-E8

The direction and magnitude of immune responses are critically affected when dead cells are disposed of. Milk fat globule-epidermal growth factor-factor 8 (MFG-E8) promotes the engulfment of apoptotic normal and cancerous cells without inducing inflammation. We have previously reported that a certain proportion of the cancer cells express abundant MFG-E8, and that such expression is associated with the shorter survival of patients with esophageal cancer who had received chemotherapy before surgery. However, the influence of tumor-derived and systemically existing MFG-E8 on antitumor immune responses has not yet been fully investigated. Herein, we showed that CTL-dependent antitumor immune responses were observed in mice with no or decreased levels of systemic MFG-E8, and that such responses were enhanced further with the administration of anti-PD-1 antibody. In mice with decreased levels of systemic MFG-E8, the dominance of regulatory T cells in tumor-infiltrating lymphocytes was inverted to CD8+ T cell dominance. MFG-E8 expression by tumor cells appears to affect antitumor immune responses only when the level of systemic MFG-E8 is lower than the physiological status. We have also demonstrated in the clinical setting that lower levels of plasma MFG-E8, but not MFG-E8 expression in tumor cells, before the treatment was associated with objective responses to anti-PD-1 therapy in patients with non-small cell lung cancer. These results suggest that systemic MFG-E8 plays a critical role during the immunological initiation process of antigen-presenting cells to increase tumor-specific CTLs. Regulation of the systemic level of MFG-E8 might induce efficient antitumor immune responses and enhance the potency of anti-PD-1 therapy.

Prediction for oxaliplatin-induced liver injury using patient-derived liver organoids

BACKGROUND

Liver injury associated with oxaliplatin (L-OHP)-based chemotherapy can significantly impact the treatment outcomes of patients with colorectal cancer liver metastases, especially when combined with surgery. To date, no definitive biomarker that can predict the risk of liver injury has been identified. This study aimed to investigate whether organoids can be used as tools to predict the risk of liver injury.

METHODS

We examined the relationship between the clinical signs of L-OHP-induced liver injury and the responses of patient-derived liver organoids in vitro. Organoids were established from noncancerous liver tissues obtained from 10 patients who underwent L-OHP-based chemotherapy and hepatectomy for colorectal cancer.

RESULTS

Organoids cultured in a galactose differentiation medium, which can activate the mitochondria of organoids, showed sensitivity to L-OHP cytotoxicity, which was significantly related to clinical liver toxicity induced by L-OHP treatment. Organoids from patients who presented with a high-grade liver injury to the L-OHP regimen showed an obvious increase in mitochondrial superoxide levels and a significant decrease in mitochondrial membrane potential with L-OHP exposure. L-OHP-induced mitochondrial oxidative stress was not observed in the organoids from patients with low-grade liver injury.

CONCLUSIONS

These results suggested that L-OHP-induced liver injury may be caused by mitochondrial oxidative damage. Furthermore, patient-derived liver organoids may be used to assess susceptibility to L-OHP-induced liver injury in individual patients.

A Method for Extending Target Regions of Genomic Profiling by Combining a Custom Probe Pool with a Commercial Targeted Panel

BACKGROUND

Next-generation sequencing (NGS)-based genomic profiling is becoming widespread in determining treatment policies for patients with tumors. Commercially available gene panels for pan-tumor targets comprise hundreds of tumor-related genes but frequently lack genes of interest in specific tumor types. In this study, we demonstrate a method for extending target regions of genomic profiling by combining a custom probe pool with a commercial targeted panel.

METHODS

We used TruSight Oncology 500 (TSO500) as a commercial targeted panel and a custom probe pool designed for all exons of the SMARCA2 gene. Sequencing libraries of custom targets were constructed using a portion of the TSO500 library solution before the hybridization-capture process. After hybridization capture, both libraries were combined and sequenced using a next-generation sequencer.

RESULTS

Sequencing results showed that >96.8% and 100% of the target exons were covered at a depth of over 100× using the TSO500 and custom panels, respectively. The custom panels had slightly better median exon coverage than the TSO500. The combined libraries of the custom and TSO500 panels showed a mapped read ratio close to the mixing ratio. Analysis of mutation-free regions showed similar accuracies between the TSO500 and custom panels regarding variant calling.

CONCLUSIONS

Our devised method easily and affordably extends the targets beyond a ready-made panel. This method provides a valuable solution until the widespread adoption of whole-exome sequencing, which is costly for large target sizes.

Metabolic clogging of mannose triggers dNTP loss and genomic instability in human cancer cells

Mannose has anticancer activity that inhibits cell proliferation and enhances the efficacy of chemotherapy. How mannose exerts its anticancer activity, however, remains poorly understood. Here, using genetically engineered human cancer cells that permit the precise control of mannose metabolic flux, we demonstrate that the large influx of mannose exceeding its metabolic capacity induced metabolic remodeling, leading to the generation of slow-cycling cells with limited deoxyribonucleoside triphosphates (dNTPs). This metabolic remodeling impaired dormant origin firing required to rescue stalled forks by cisplatin, thus exacerbating replication stress. Importantly, pharmacological inhibition of de novo dNTP biosynthesis was sufficient to retard cell cycle progression, sensitize cells to cisplatin, and inhibit dormant origin firing, suggesting dNTP loss-induced genomic instability as a central mechanism for the anticancer activity of mannose.

Eribulin mesylate exerts antitumor effects via CD103

Eribulin mesylate (ERB) is a synthetic analog of halichondrin B, inhibiting tumor cell growth by disrupting microtubule function. Recently, anticancer drugs have been shown to not only act directly on tumor cells but also to exert antitumor effects by modifying the tumor environment. Although ERB has also been speculated to modify the tumor microenvironment including the immune response to tumors, the precise mechanism remains unclear. In our study, ERB suppressed the tumor growth of MC38 colon cancer in wildtype mice, whereas ERB failed to inhibit the tumor growth in Rag1-deficient mice which lack both B and T cells. Moreover, depletion of either CD4+ or CD8+ T cells abrogated the antitumor effect of ERB, indicating that both CD4+ and CD8+ T cells play an important role in ERB-induced antitumor effects. Furthermore, ERB treatment increased the number of tumor infiltrating lymphocytes (TILs) as well as the expression of activation markers (CD38 and CD69), immune checkpoint molecules (LAG3, TIGIT and Tim3) and cytotoxic molecules (granzyme B and perforin) in TILs. ERB upregulated E-cadherin expression in MC38. CD103 is a ligand of E-cadherin and induces T-cell activation. ERB increased the proportion of CD103+ cells in both CD4+ and CD8+ TILs. The ERB-induced antitumor effect with the increased TIL number and the increased expression of activation markers, inhibitory checkpoint molecules and cytotoxic molecules in TILs was abrogated in CD103-deficient mice. Collectively, these results suggest that ERB exerts antitumor effects by upregulation of E-cadherin expression in tumor cells and subsequent activation of CD103+ TILs.

GSTA4 Governs Melanoma Immune Resistance and Metastasis

IMPLICATIONS

Considering the importance of GSTA4 in controlling IFNγ responsiveness and the metastatic potential of other melanoma cells, our results highlight a novel mechanism whereby cancer cells escape from host immunity and gain metastatic ability by acquiring resistance to oxidative stress responses through the upregulation of GSTA4.

Cancer-derived cholesterol sulfate is a key mediator to prevent tumor infiltration by effector T cells

Effective tumor immunotherapy requires physical contact of T cells with cancer cells. However, tumors often constitute a specialized microenvironment that excludes T cells from the vicinity of cancer cells, and its underlying mechanisms are still poorly understood. DOCK2 is a Rac activator critical for migration and activation of lymphocytes. We herein show that cancer-derived cholesterol sulfate (CS), a lipid product of the sulfotransferase SULT2B1b, acts as a DOCK2 inhibitor and prevents tumor infiltration by effector T cells. Using clinical samples, we found that CS was abundantly produced in certain types of human cancers such as colon cancers. Functionally, CS-producing cancer cells exhibited resistance to cancer-specific T-cell transfer and immune checkpoint blockade. Although SULT2B1b is known to sulfate oxysterols and inactivate their tumor-promoting activity, the expression levels of cholesterol hydroxylases, which mediate oxysterol production, are low in SULT2B1b-expressing cancers. Therefore, SULT2B1b inhibition could be a therapeutic strategy to disrupt tumor immune evasion in oxysterol-non-producing cancers. Thus, our findings define a previously unknown mechanism for tumor immune evasion and provide a novel insight into the development of effective immunotherapies.

Establishment of organoids using residual samples from saline flushes during endoscopic ultrasound-guided fine-needle aspiration in patients with pancreatic cancer

Background and study aims  In patients with pancreatic cancer (PC), patient-derived organoid cultures can be useful tools for personalized drug selection and preclinical evaluation of novel therapies. To establish a less invasive method of creating organoids from a patient's tumor, we examined whether PC organoids can be established using residual samples from saline flushes (RSSFs) during endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). Methods  Five patients with PC who underwent EUS-FNA were enrolled in a prospective study conducted at our institution. RSSFs obtained during EUS-FNA procedures were collected. An organoid culture was considered as established when ≥ 5 passages were successful. Organoid-derived xenografts were created using established organoids. Results  EUS-FNA was performed using a 22- or 25-gauge lancet needle without complications. Patient-derived organoids were successfully established in four patients (80.0 %) with the complete medium and medium for the selection of KRAS mutants. Organoid-derived xenografts were successfully created and histologically similar to EUS-FNA samples. Conclusions  Patient-derived PC organoids were successfully established using EUS-FNA RSSFs, which are produced as a byproduct of standard manipulations, but are usually not used for diagnosis. This method can be applied to all patients with PC, without additional invasive procedures, and can contribute to the development of personalized medicine and molecular research.

Potent anti-tumor effects of receptor-retargeted syncytial oncolytic herpes simplex virus

Most oncolytic virotherapy has thus far employed viruses deficient in genes essential for replication in normal cells but not in cancer cells. Intra-tumoral injection of such viruses has resulted in clinically significant anti-tumor effects on the lesions in the vicinity of the injection sites but not on distant visceral metastases. To overcome this limitation, we have developed a receptor-retargeted oncolytic herpes simplex virus employing a single-chain antibody for targeting tumor-associated antigens (RR-oHSV) and its modified version with additional mutations conferring syncytium formation (RRsyn-oHSV). We previously showed that RRsyn-oHSV exhibits preserved antigen specificity and an ∼20-fold higher tumoricidal potency in vitro relative to RR-oHSV. Here, we investigated the in vivo anti-tumor effects of RRsyn-oHSV using human cancer xenografts in immunodeficient mice. With only a single intra-tumoral injection of RRsyn-oHSV at very low doses, all treated tumors regressed completely. Furthermore, intra-venous administration of RRsyn-oHSV resulted in robust anti-tumor effects even against large tumors. We found that these potent anti-tumor effects of RRsyn-oHSV may be associated with the formation of long-lasting tumor cell syncytia not containing non-cancerous cells that appear to trigger death of the syncytia. These results strongly suggest that cancer patients with distant metastases could be effectively treated with our RRsyn-oHSV.

NKG2D defines tumor-reacting effector CD8+ T cells within tumor microenvironment

For successful immunotherapy for cancer, it is important to understand the immunological status of tumor antigen-specific CD8⁺ T cells in the tumor microenvironment during tumor progression. In this study, we monitored the behavior of B16OVA-Luc cells in mice immunized with a model tumor antigen ovalbumin (OVA). Using bioluminescence imaging, we identified the time series of OVA-specific CD8⁺ T-cell responses during tumor progression: initial progression, immune control, and the escape phase. As a result of analyzing the status of tumor antigen-specific CD8⁺ cells in those 3 different phases, we found that the expression of NKG2D defines tumor-reacting effector CD8⁺ T cells. NKG2D may control the fate and TOX expression of tumor-reacting CD8⁺ T cells, considering that NKG2D blockade in OVA-vaccinated mice delayed the growth of the B16OVA-Luc2 tumor and increased the presence of tumor-infiltrating OVA-specific CD8⁺ T cells.

Atezolizumab with bevacizumab, paclitaxel and carboplatin was effective for patients with SMARCA4-deficient thoracic sarcoma

SMARCA4-deficient thoracic sarcoma (DTS) is a recently noted progressive thoracic malignancy. We recently experienced three cases of SMARCA4-DTS who were treated with atezolizumab in combination with bevacizumab, paclitaxel and carboplatin (ABCP) as the first-line therapy. Immunohistopathological analysis revealed absent expression of SMARCA4 in all cases. The tumor mutational burden was over 11/Mb and mutations in SMARCA4 and TP53 were detected in all three cases. Partial response to ABCP treatment was observed in all three cases, with a progression-free survival of approximately 6 months or longer and a continuous response of 1 year or longer in one case. The first-line ABCP treatment demonstrated durable efficacy in SMARCA4-DTS regardless of the degree of PD-L1 expression.

ASK1 suppresses NK cell-mediated intravascular tumor cell clearance in lung metastasis

Tumor metastasis is the leading cause of death worldwide and involves an extremely complex process composed of multiple steps. Our previous study demonstrated that apoptosis signal‐regulating kinase 1 (ASK1) deficiency in mice attenuates tumor metastasis in an experimental lung metastasis model. However, the steps of tumor metastasis regulated by ASK1 remain unclear. Here, we showed that ASK1 deficiency in mice promotes natural killer (NK) cell‐mediated intravascular tumor cell clearance in the initial hours of metastasis. In response to tumor inoculation, ASK1 deficiency upregulated immune response‐related genes, including interferon‐gamma (IFNγ). We also revealed that NK cells are required for these anti‐metastatic phenotypes. ASK1 deficiency augmented cytokine production chemoattractive to NK cells possibly through induction of the ligand for NKG2D, a key activating receptor of NK cells, leading to further recruitment of NK cells into the lung. These results indicate that ASK1 negatively regulates NK cell‐dependent anti‐tumor immunity and that ASK1‐targeted therapy can provide a new tool for cancer immunotherapy to overcome tumor metastasis.

Clinical significance of CD8+ and FoxP3+ tumor-infiltrating lymphocytes and MFG-E8 expression in lower rectal cancer with preoperative chemoradiotherapy

Preoperative chemoradiotherapy (CRT) for rectal cancer contributes to tumor down-staging and decreases locoregional recurrence. However, each patient shows a significantly different response to CRT. Therefore, the identification of predictive factors to CRT response would be beneficial to avoid unnecessary treatment. Cancer immunity in patients has been suggested to play an important role in the eradication of the tumor by CRT. In the present study, the utility of CD8⁺ and forkhead box P3 (FoxP3)⁺ tumor-infiltrating lymphocytes (TILs) and the expression of a novel immuno-regulatory factor, lactadherin (MFG-E8), in predicting CRT effectiveness in patients with rectal cancer was examined. A total of 61 patients with rectal cancer, who underwent curative resection following CRT were included in the study. The numbers of CD8⁺ and FoxP3⁺ TILs in a biopsy taken before CRT and MFG-E8 expression level in the specimens obtained at the time of the surgery after CRT were examined using immunohistochemical staining, and their association with clinicopathological characteristics, including patient survival, was determined. The tumors with more CD8⁺ TILs in the biopsy samples before CRT showed a significantly more favorable CRT response. The patients with tumors and a higher number of CD8⁺ TILs before CRT also exhibited significantly longer disease-free and overall survival times. Higher MFG-E8 expression level in post-CRT specimens was significantly associated with favorable CRT response; however, no significant association was found with any other clinicopathological characteristics, including survival time. The number of CD8⁺ TILs before CRT was a valuable predictor for CRT response and was associated with favorable prognosis in patients with lower rectal cancer and who were treated with CRT. High MFG-E8 expression level after CRT was also associated with a favorable CRT response.

The liposome of trehalose dimycolate extracted from M. bovis BCG induces antitumor immunity via the activation of dendritic cells and CD8+ T cells

Intravesical Bovis bacillus Calmette-Guérin (BCG) therapy is the most effective immunotherapy for bladder cancer, but it sometime causes serious side effects because of its inclusion of live bacteria. It is necessary to develop a more active but less toxic immunotherapeutic agent. Trehalose 6,6'-dimycolate (TDM), the most abundant hydrophobic glycolipid of the BCG cell wall, has been reported to show various immunostimulatory activities such as granulomagenesis and adjuvant activity. Here, we developed cationic liposomes incorporating TDM purified from Mycobacterium bovis BCG Connaught, and we investigated the antitumor effect of the cationic liposome TDM (Lip-TDM). Lip-TDM exerted an antitumor effect in bladder cancer, colon cancer, and melanoma-bearing mouse models that was comparable or even superior to that of BCG, with no body weight loss or granuloma formation. The antitumor effect of Lip-TDM disappeared in two types of mice: those with depletion of CD8⁺ T cells, and those with knockout of macrophage-inducible C-type lectin (Mincle) which recognize TDM. Lip-TDM treatment enhanced the maturation and migration of dendritic cells in the tumor microenvironment in a Mincle-dependent manner. Our results elucidate mechanisms that underlie Lip-TDM treatment and suggest that Lip-TDM has potential as a safe and effective treatment for various cancers.

Antimetastatic effects of thalidomide by inducing the functional maturation of peripheral natural killer cells

Thalidomide and its analogues are known as immunomodulatory drugs (IMiDs) that possess direct antimyeloma effects, in addition to other secondary effects, including antiangiogenic, antiinflammatory, and immunomodulatory effects. Although the involvement of natural killer (NK) cells in the antitumor effects of IMiDs has been reported, it is unclear whether IMiDs inhibit cancer cell metastasis by regulating the antitumor function of NK cells. In this study, we examined the protective effects of thalidomide against cancer metastasis by focusing on its immunomodulatory effects through NK cells. Using experimental lung metastasis models, we found that pharmacological effects of thalidomide on host cells, but not its direct anticancer tumor effects, are responsible for the inhibition of lung metastases. To exert the antimetastatic effects of thalidomide, both γ‐interferon (IFN‐γ) production and direct cytotoxicity of NK cells were essential, without notable contribution from T cells. In thalidomide‐treated mice, there was a significant increase in the terminally differentiated mature CD27^lo NK cells in the peripheral tissues and NK cells in thalidomide‐treated mice showed significantly higher cytotoxicity and IFN‐γ production. The NK cell expression of T‐bet was upregulated by thalidomide treatment and the downregulation of glycogen synthase kinase‐3β expression was observed in thalidomide‐treated NK cells. Collectively, our study suggests that thalidomide induces the functional maturation of peripheral NK cells through alteration of T‐bet expression to inhibit lung metastasis of cancer cells.

Oncolytic Herpes Simplex Virus Vectors Fully Retargeted to Tumor- Associated Antigens

Oncolytic virotherapy is a novel therapeutic modality for malignant diseases that exploits selective viral replication in cancer cells. Herpes simplex virus (HSV) is a promising agent for oncolytic virotherapy due to its broad cell tropism and the identification of mutations that favor its replication in tumor over normal cells. However, these attenuating mutations also tend to limit the potency of current oncolytic HSV vectors that have entered clinical studies. As an alternative, vector retargeting to novel entry receptors has the potential to achieve tumor specificity at the stage of virus entry, eliminating the need for replication-attenuating mutations. Here, we summarize the molecular mechanism of HSV entry and recent advances in the development of fully retargeted HSV vectors for oncolytic virotherapy. Retargeted HSV vectors offer an attractive platform for the creation of a new generation of oncolytic HSV with improved efficacy and specificity.

Immunoregulatory influence of abundant MFG-E8 expression by esophageal cancer treated with chemotherapy

Milk fat globule‐epidermal growth factor factor 8 (MFG‐E8) is secreted from macrophages and is known to induce immunological tolerance mediated by regulatory T cells. However, the roles of the MFG‐E8 that is expressed by cancer cells have not yet been fully examined. Expression of MFG‐E8 was examined using immunohistochemistry in surgical samples from 134 patients with esophageal squamous cell carcinoma. The relationships between MFG‐E8 expression levels and clinicopathological factors, including tumor‐infiltrating lymphocytes, were evaluated. High MFG‐E8 expression was observed in 23.9% of the patients. The patients with tumors highly expressing MFG‐E8 had a significantly higher percentage of neoadjuvant chemotherapy (NAC) history (P < .0001) and shorter relapse‐free survival (P = 0.012) and overall survival (OS; P = .0047). On subgroup analysis, according to NAC history, patients with high MFG‐E8 expression had significantly shorter relapse‐free survival (P = .027) and OS (P = .0039) only when they had been treated with NAC. Furthermore, tumors with high MFG‐E8 expression had a significantly lower ratio of CD8⁺ T cells/regulatory T cells in tumor‐infiltrating lymphocytes (P = .042) only in the patients treated with NAC, and those with a lower ratio had a shorter OS (P = .026). High MFG‐E8 expression was also found to be an independent prognostic factor in multivariate analysis. The abundant MFG‐E8 expression in esophageal squamous cell carcinoma might have a negative influence on the long‐term survival of patients after chemotherapy by affecting T‐cell regulation in the tumor microenvironment.

Lung-resident natural killer cells control pulmonary tumor growth in mice

Accumulating evidence indicates the importance of natural killer (NK) cells in controlling tumor growth and metastasis. NK cell subsets display diversities in their function and tissue distribution and Mac-1hi CD27lo NK cells are the predominant population of lung-resident NK cells. Although the lung is a major organ where primary tumor develops and cancer cells metastasize, there is no clear evidence whether circulating NK cells and/or tissue-resident NK cells control tumor growth in the lung. In the present study, we examined an antitumor function of lung-resident NK cells to control pulmonary tumor growth. In an orthotopic lung tumor model, NK cells controlled pulmonary tumor growth, and mature circulating NK cell subsets were increased in tumor-bearing lungs through a C-X-C motif chemokine receptor 3 (CXCR3)-dependent mechanism. Although such increase in migratory NK cell subsets can be blocked by anti-CXCR3 treatment, there was no difference in pulmonary tumor growth in anti-CXCR3-treated mice compared with control mice. In addition to pulmonary tumor growth, lung-resident NK cells, but not migratory NK cells, play a dominant role in controlling metastatic growth of cancer cells in lung. These results strongly indicate an importance of lung-resident NK cells for controlling pulmonary tumor growth.

Acute Graft Rejection and Formation of De Novo Donor-Specific Antibodies Triggered by Low Cyclosporine Levels and Interferon Therapy for Recurrent Hepatitis C Infection After Liver Transplantation: A Case Report

BACKGROUND

We report a case of acute rejection of a liver graft, together with the occurrence of de novo donor-specific antibodies (DSAs), in a 53-year-old Japanese man who had undergone deceased-donor liver transplantation.

METHODS

The graft rejection was triggered by low cyclosporine levels and pegylated interferon treatment for the recurrence of hepatitis C virus (HCV) infection 18 months after transplantation. Although the graft was ABO-compatible, pre-formed DSA B51 was detected; therefore, total plasma exchange was performed and intravenous rituximab (500 mg/body) was administered before transplantation.

RESULTS

DSA was absent 6 months after transplantation. HCV recurrence was treated with pegylated interferon-α-2a. Renal function deteriorated with this anti-HCV therapy, with serum cyclosporine levels decreasing to 50 ng/mL. A rapid virologic response was achieved, but liver function deteriorated after 3 months of anti-HCV therapy, with histologic evidence of acute cellular rejection and formation of de novo DSAs. Anti-thymocyte globulin was administered for 5 days, which led to immediate improvement in liver function. However, renal function declined, warranting hemodialysis. The patient recovered 2 months after acute rejection, although de novo DSAs persisted.

CONCLUSIONS

Careful immunologic monitoring may be required for patients receiving interferon therapy for HCV infection to maintain sufficient blood levels of immunosuppressive agents and to prevent acute liver graft rejection.

Reply: Lymph stasis promotes tumor growth

Our study suggested that surgical damage of the lymphatic system promotes tumor progression via impaired immune response. However, as pointed out by Valerio et al, lymph stasis is likely to induce immune stasis, resulting in not only enhanced tumor growth but also tumor generation. Although mechanisms of the tumor generation may not only include impaired immune response but also other factors induced by lymph stasis, we should avoid unnecessary lymphatic disruption in any surgeries and carefully consider the flap design to minimalize lymphatic disruption even in cases with benign tumors.

NK Cells Control Tumor-Promoting Function of Neutrophils in Mice

Although natural killer (NK) cells are recognized as direct antitumor effectors, the ability of NK cells to control cancer-associated inflammation, which facilitates tumor progression, remains unknown. In this study, we demonstrate that NK cells control tumor-promoting inflammation through functional modification of neutrophils. NK cells control the tumor-promoting function of neutrophils through an IFNγ-dependent mechanism. Tumor progression in an NK cell-depleted host is diminished when the IL17A-neutrophil axis is absent. In NK cell-depleted mice, neutrophils acquire a tumor-promoting phenotype, characterized by upregulation of VEGF-A expression, which promotes tumor growth and angiogenesis. A VEGFR inhibitor which preferentially suppressed tumor growth in NK cell-depleted mice was dependent on neutrophils. Furthermore, the systemic neutropenia caused by an antimetabolite treatment showed an anticancer effect only in mice lacking NK cells. Thus, NK cells likely control the tumor-promoting and angiogenic function of neutrophils. Cancer Immunol Res; 6(3); 348-57. ©2018 AACR.

Surgical damage to the lymphatic system promotes tumor growth via impaired adaptive immune response

BACKGROUND

Both lymph nodes (LNs) and lymphatic channels from primary sites to regional LNs are critical for initiation of adaptive immunity. However, as LNs are common metastatic sites in skin cancers, LN biopsies or dissections are frequently performed. In addition, reconstructive skin flaps after tumor resection may damage lymphatic flow from primary sites to regional LNs.

OBJECTIVE

This study was designed to investigate the effect on tumor progression by such surgeries.

METHODS

We developed a mouse model that simulates LNs dissection or skin flap that blocks lymphatic flow from primary sites to regional LNs and monitored tumor progression.

RESULTS

As a poor immunogenic tumor line, the growth of inoculated B16F10 melanoma into syngeneic C57BL/6 mice was not affected by these surgeries. However, the growth of the same cell line in allogenic Balb/c mice was accelerated while immune cell infiltration (CD4⁺ and CD8⁺ T cells) into the tumor was reduced by these surgeries. In addition, both cytotoxicity against B16F10 melanoma and numbers of apoptotic tumor cells were diminished by these surgeries. Similarly, tumor growth of the immunogenic MC38 cell line in syngeneic C57BL/6 mice was accelerated and immune cell infiltration and apoptotic tumor cells were reduced by these surgeries.

CONCLUSION

These results strongly indicate that surgical damage of the lymphatic system may promote tumor progression via impaired adaptive immune response.

Cytokine biomarkers to predict antitumor responses to nivolumab suggested in a phase 2 study for advanced melanoma

Promising antitumor activities of nivolumab, a fully humanized IgG4 inhibitor antibody against the programmed death‐1 protein, were suggested in previous phase 1 studies. The present phase 2, single‐arm study (JAPIC‐CTI #111681) evaluated the antitumor activities of nivolumab and explored its predictive correlates in advanced melanoma patients at 11 sites in Japan. Intravenous nivolumab 2 mg/kg was given repeatedly at 3‐week intervals to 35 of 37 patients enrolled from December 2011 to May 2012 until they experienced unacceptable toxicity, disease progression, or complete response. Primary endpoint was objective response rate. Serum levels of immune modulators were assessed at multiple time points. As of 21 October 2014, median response duration, median progression‐free survival, and median overall survival were 463 days, 169 days, and 18.0 months, respectively. The overall response rate and 1‐ and 2‐year survival rates were 28.6%, 54.3%, and 42.9%, respectively. Thirteen patients remained alive at the end of the observation period and no deaths were drug related. Grade 3–4 drug‐related adverse events were observed in 31.4% of patients. Pretreatment serum interferon‐γ, and interleukin‐6 and ‐10 levels were significantly higher in the patients with objective tumor responses than in those with tumor progression. In conclusion, giving repeated i.v. nivolumab had potent and durable antitumor effects and a manageable safety profile in advanced melanoma patients, strongly suggesting the usefulness of nivolumab for advanced melanoma and the usefulness of pretreatment serum cytokine profiles as correlates for predicting treatment efficacy.

Antiglycopeptide Mouse Monoclonal Antibody LpMab-21 Exerts Antitumor Activity Against Human Podoplanin Through Antibody-Dependent Cellular Cytotoxicity and Complement-Dependent Cytotoxicity

The interaction between podoplanin (PDPN) and C-type lectin-like receptor 2 (CLEC-2) is involved in tumor malignancy. We have established many monoclonal antibodies (mAbs) against human podoplanin using the cancer-specific mAb (CasMab) technology. LpMab-21, one of the mouse antipodoplanin mAbs, is of the IgG_2a subclass, and its minimum epitope was determined to be Thr76-Arg79 of the human podoplanin. Importantly, sialic acid is linked to Thr76; therefore, LpMab-21 is an antiglycopeptide mAb (GpMab). In this study, we investigated whether LpMab-21 shows antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) against human podoplanin-expressing cancer cell lines in vitro and also studied its antitumor activities using a xenograft model. LpMab-21 showed high ADCC and CDC activities against not only podoplanin-expressing Chinese hamster ovary cells but also LN319 glioblastoma cells and PC-10 lung cancer cells, both of which endogenously express podoplanin. Furthermore, LpMab-21 decreased tumor growth in vivo, indicating that LpMab-21 could be useful for antibody therapy against human podoplanin-expressing cancers.

MELD and Child-Pugh Scores Are Related to Immune Status of Intrahepatic Natural Killer Cells in Liver Transplant Candidates

BACKGROUND

The role and phenotypic alterations of intrahepatic natural killer (NK) cells in liver disease were investigated. Although intrahepatic NK cells reportedly functionally deteriorate in the fibrotic liver, it remains unclear how the clinical severity of liver disease affects intrahepatic NK cells in patients with advanced liver failure.

METHODS

We analyzed the phenotypic properties of intrahepatic NK cells by using mononuclear cells extracted from ex vivo liver perfusate effluents from patients who underwent liver transplantation. The relationship between the clinical severity of liver disease and the phenotype of intrahepatic NK cells in these patients was also evaluated. To estimate the immunological responsiveness of intrahepatic NK cells, phenotypic enhancement after interleukin-2 stimulation was analyzed.

RESULTS

Intrahepatic NK cells from patients with advanced liver failure exhibited down-regulated monomodal expression of NKp46, a major activating molecule. Notably, the expression level of NKp46 decreased depending on the severity of liver disease, Model for End-Stage Liver Disease score, and Child-Pugh score rather than the etiology. After in vitro recombinant interleukin-2 stimulation, the enhancement of expression of cytotoxic molecules, NKp44, and tumor necrosis factor-related apoptosis-inducing ligand was significantly impaired in intrahepatic NK cells from patients with liver failure, concurrently with decreased expression of CD122 and interleukin-2 receptor beta.

CONCLUSIONS

Our results suggest that terminal deterioration of liver environments by chronic liver disease impairs the potential of local NK cells, depending on the severity of the deterioration. These influences of advanced liver failure on intrahepatic NK cells may be attributed to multicentric carcinogenesis in patients with liver failure.

IL-17A-producing CD30(+) Vδ1 T cells drive inflammation-induced cancer progression

Although it has been suspected that inflammation is associated with increased tumor metastasis, the exact type of immune response required to initiate cancer progression and metastasis remains unknown. In this study, by using an in vivo tumor progression model in which low tumorigenic cancer cells acquire malignant metastatic phenotype after exposure to inflammation, we found that IL‐17A is a critical cue for escalating cancer cell malignancy. We further demonstrated that the length of exposure to an inflammatory microenvironment could be associated with acquiring greater tumorigenicity and that IL‐17A was critical for amplifying such local inflammation, as observed in the production of IL‐1β and neutrophil infiltration following the cross‐talk between cancer and host stromal cells. We further determined that γδT cells expressing Vδ1 semi‐invariant TCR initiate cancer‐promoting inflammation by producing IL‐17A in an MyD88/IL‐23‐dependent manner. Finally, we identified CD30 as a key molecule in the inflammatory function of Vδ1T cells and the blockade of this pathway targeted this cancer immune‐escalation process. Collectively, these results reveal the importance of IL‐17A‐producing CD30⁺ Vδ1T cells in triggering inflammation and orchestrating a microenvironment leading to cancer progression.

Negative influence of programmed death-1-ligands on the survival of esophageal cancer patients treated with chemotherapy

The programmed death‐1/programmed death‐1 ligands (PD‐1/PD‐L) pathway plays an important role in immunological tumor evasion. However, the clinical significance of the PD‐L (L1 and L2) expression in esophageal cancer treated with chemotherapy has not been fully investigated. We examined the expression of PD‐L of the primary tumors obtained from 180 esophageal cancer patients who underwent radical resection with or without neoadjuvant chemotherapy (NAC) using immunohistochemical staining. The relationship between the expression patterns and clinico‐pathological characteristics was examined. In the present study, 53 patients (29.4%) and 88 patients (48.3%) were classified into positive for PD‐L1 and PD‐L2 expression, respectively. In all the patients examined, overall survival rates of the patients with tumors positive for PD‐L1 or PD‐L2 were significantly worse than those with tumors negative for PD‐L1 or PD‐L2 (P = 0.0010 and P = 0.0237, respectively). However, subgroup analysis showed that these tendencies are only found in the patients treated with NAC, and not in those without NAC. The patients with positive PD‐L1 expression had a significantly higher rate of NAC history (P = 0.0139), but those with positive PD‐L2 expression did not have a significantly high rate of NAC history (P = 0.6127). There is no significant relationship between PD‐L1 expression and response to chemotherapy (P = 0.3118), but patients with positive PD‐L2 expression had significantly inferior responses to chemotherapy (P = 0.0034). The PD‐1/PD‐L pathway might be an immunological mechanism associated with the long‐term effectiveness of chemotherapy in esophageal cancer patients. Further investigation into the roles of PD‐1 pathway in chemotherapy could lead to the development of better treatment options for this disease.

Augmentation of Immune Checkpoint Cancer Immunotherapy with IL18

PURPOSE

Recent clinical trials and animal models demonstrated that immune checkpoint blockade enhanced effector cell responses and tumor rejection; however, further development and improvement of cancer immunotherapy is necessary for more favorable objective responses. In this study, we examined the effect of IL18 on the antitumor effect of immune checkpoint inhibitors.

EXPERIMENTAL DESIGN

We examined the effect of IL18 on the peritoneal dissemination of CT-26 cells or tail vein injection metastasis of B16/F10 cells using antiprogrammed death-1 ligand-1 (αPD-L1) and/or anti-CTL-associated antigen-4 (αCTLA-4) mAbs.

RESULT

Massive ascites developed after intraperitoneal inoculation of CT-26, resulting in animal death within 30 days. Treatment of mice with αPD-L1 and/or αCTLA-4 significantly prolonged their survival, and a combination of the antibodies and IL18 provided a much greater therapeutic benefit. The combination modality led to the accumulation of precursor of mature natural killer (pre-mNK) cells in the peritoneal cavity together with increased CD8(+) T and decreased CD4(+)CD25(+)Foxp3(+) T cells. Depletion of the pre-mNK cells abrogated the therapeutic effects and increased the number of CD4(+)CD25(+)Foxp3(+) T cells. The combination treatment also suppressed tail vein injection metastasis of B16/F10 cells.

CONCLUSIONS

The results demonstrated that IL18 enhanced therapeutic effects of immune checkpoint blockade against peritoneal dissemination of carcinoma or tail vein injection metastasis of melanoma through accumulation of pre-mNK cells, memory-type CD8(+) T cells, and suppression of CD4(+)CD25(+)Foxp3(+) T cells. A combination of immune checkpoint inhibitors with IL18 may give a suggestion to the development of next-generation cancer immunotherapy. Clin Cancer Res; 22(12); 2969-80. ©2016 AACR.

Uremic serum contains humoral factor(s) larger than fifty kilodaltons which suppresses endothelin production in cultured endothelial cells

Direct effects of human uremic serum on the production of endothelin-1 in cultured porcine endothelial cells were examined in this study. Uremic serum decreased the level of monomeric endothelin-1 secreted into the culture medium by endothelial cells. This effect occurred at a transcriptional step because uremic serum decreased the endothelin-1 mRNA level in those cells. For the partial characterization of this inhibitory activity, uremic serum was fractionated with a centricut column. Uremic serum contains humoral factor(s) larger than 50 kD which suppress the endothelin-1 mRNA level in cultured endothelial cells.

Clinical efficacy of simultaneous splenectomy in liver transplant recipients with hepatitis C virus

BACKGROUND

Interferon (IFN) therapy is a well-established antiviral treatment for hepatitis C virus (HCV) - infected patients. However, susceptibility to thrombocytopenia is a major obstacle in its initiation or continuation, particularly in patients with HCV who underwent liver transplantation (LT). We previously showed that the coexistence of splenomegaly and thrombocytopenia could result in persistent thrombocytopenia after LT. Here we retrospectively evaluated the validity of this criterion for simultaneous splenectomy in recipients with HCV.

PATIENTS AND METHODS

Subjects included 36 recipients with HCV who received LT between January 2006 and February 2012 at Hiroshima University. We analyzed the spleen volume, body surface area, platelet (PLT) count, and rate of completion or continuation with IFN therapy in these recipients.

RESULT

Of these recipients, 30 did not require simultaneous splenectomy according to the criterion, and 24 actually did not receive simultaneous splenectomy. In this group, 21 (87.5%) started IFN therapy. Fifteen (71.4%) of these recipients completed or continued IFN therapy, whereas 13 (61.9%) achieved either a sustained virological response (SVR) or an end-of-treatment response. The PLT count increased to >100,000/mm(3) 1 month after LT in 16 (66.7%) recipients from this group.

CONCLUSION

Our criterion detected the PLT count outcome after LT in recipients with HCV and achieved a better SVR result after IFN therapy.

Identification of human leukocyte antigen-A24-restricted epitope peptides derived from gene products upregulated in lung and esophageal cancers as novel targets for immunotherapy

For the development of cancer vaccine therapies, we have searched for possible epitope peptides that can elicit cytotoxic T lymphocytes (CTL) to the TTK protein kinase (TTK), lymphocyte antigen 6 complex locus K (LY6K) and insulin-like growth factor (IGF)-II mRNA binding protein 3 (IMP-3), which were previously identified to be transactivated in the majority of lung and esophageal cancers. We screened 31, 17 and 17 candidate human leukocyte antigen (HLA)-A*2402-binding peptides to parts of TTK, LY6K and IMP-3, respectively. As a result, we successfully established strong CTL clones stimulated by TTK-567 (SYRNEIAYL), LY6K-177 (RYCNLEGPPI) and IMP-3-508 (KTVNELQNL) that have specific cytotoxic activities against the HLA-A24-positive target cells pulsed with the candidate peptides. Subsequent analysis of the CTL clones also revealed their cytotoxic activities against lung and esophageal tumor cells that endogenously express TTK, LY6K or IMP-3. A cold target inhibition assay further confirmed that the CTL cell clones specifically recognized the MHC class I–peptide complex. Our results strongly imply that TTK, LY6K and IMP-3 are novel tumor-associated antigens recognized by CTL, and TTK-567 (SYRNEIAYL), LY6K-177 (RYCNLEGPPI) and IMP-3-508 (KTVNELQNL) are HLA-A24-restricted epitope peptides that can induce potent and specific immune responses against lung and esophageal cancer cells expressing TTK, LY6K and IMP-3.

Long-time correlation in non-Markovian dephasing of an exciton-phonon system in InAs quantum dots

We have observed a time-correlated frequency fluctuation in non-Markovian dephasing of excitons in InAs quantum dots using a six-wave mixing technique. In this measurement, the arrival times of the excitation pulses were controlled to eliminate the influence of Markovian dephasing and to measure the pure non-Markovian behavior. The experimental result shows that the time correlation of the frequency fluctuation due to exciton-phonon interactions was maintained in the quantum dots for over 10 ps. This long-time correlation is caused by the modification of the phonon coupling distribution.

[Mechanism of action for immunotherapy drugs]

Cancer therapy utilizing cellular immunity has been developed using various reagents including stimulus for innate immunity, cytokines, vaccines, autologous cells and gene-vectors. Recently, mono-clonal antibodies have been added to the list as well. These reagents of modalities have been developed base on the findings in the basic research in cellular immunology which has been proven to have potent activities to suppress the tumor growth in either in vitro or in vivo. This review describes the characteristics of the reagents of modalities focusing on their mechanisms of action.

Sox9 is upstream of microRNA-140 in cartilage

MicroRNA-140 (miR-140) is specifically expressed in developing cartilage tissues. We have previously reported that miR-140 plays an important role during palatal cartilage development by modulating platelet-derived growth factor receptor alpha (pdgfra) in zebrafish. However, the regulatory mechanism of miR-140 in cartilage is still unknown. Using developing zebrafish, sox9a mutant (sox9a-/-) and sox9b mutant (sox9b-/-) zebrafish and SOX9 small interfering RNA in human chondrocytes, T/C-28 cells, we found that miR-140 is regulated by the cartilage master transcription regulator Sox9 in zebrafish and mammalian cells.