Pathological Complete Response to Liver Metastasis With Pembrolizumab in a Previously Treated Patient With Microsatellite Instability-high Colorectal Cancer.

BACKGROUND/AIM: Immune checkpoint inhibitors are effective in treating microsatellite instability-high (MSI-H) metastatic colorectal cancer (CRC). Pathological complete response to immune checkpoint inhibitors for MSI-H metastatic CRC have been described in several reports. Liver metastasis is known to predict resistance to ani-programmed death 1 (PD-1)/PD-1 ligand 1 (PD-L1) therapy in several cancers, including CRC. CASE REPORT: Herein, we report the case of a 23-year-old man with MSI-H colorectal liver metastasis who exhibited a pathological complete response to pembrolizumab following systemic chemotherapies. Pathological examination of the primary lesion revealed strong HLA-class I and HLA-DR expression in cancer cells. Elevated PD-L1 expression was observed in areas of increased CD8-postive T cell infiltration. Additional pathological study of regional lymph nodes showed increased PD-L1 and CD169 expression. CONCLUSION: A detailed pathological examination revealed PD-L1 expression not only in the primary CRC lesion but also in regional lymph nodes. Recent studies have highlighted the significance of regional lymph nodes in anti-cancer immune responses. Therefore, pathological studies using resected lymph nodes might be beneficial for predicting the response of anti-PD-1/PD-L1 therapy.

Surface Markers and Chemokines/Cytokines of Tumor-Associated Macrophages in Osteosarcoma and Other Carcinoma Microenviornments-Contradictions and Comparisons.

Osteosarcoma (OS) is the most common primary bone tumor in children and adolescents. Prognosis is improving with advances in multidisciplinary treatment strategies, but the development of new anticancer agents has not, and improvement in prognosis for patients with pulmonary metastases has stalled. In recent years, the tumor microenvironment (TME) has gained attention as a therapeutic target for cancer. The immune component of OS TME consists mainly of tumor-associated macrophages (TAMs). They exhibit remarkable plasticity, and their phenotype is influenced by the TME. In general, surface markers such as CD68 and CD80 show anti-tumor effects, while CD163 and CD204 show tumor-promoting effects. Surface markers have potential value as diagnostic and prognostic biomarkers. The cytokines and chemokines produced by TAMs promote tumor growth and metastasis. However, the role of TAMs in OS remains unclear to date. In this review, we describe the role of TAMs in OS by focusing on TAM surface markers and the TAM-produced cytokines and chemokines in the TME, and by comparing their behaviors in other carcinomas. We found contrary results from different studies. These findings highlight the urgency for further research in this field to improve the stalled OS prognosis percentages.

Potential protumor function of CD74 in clear cell renal cell carcinoma.

CD74 is a transmembrane protein that functions as a specialized chaperone of HLA class II and CD74 in tumor cells was suggested to be involved in cell proliferation in several kinds of malignant tumors. CD74 is also known to be expressed in macrophages, therefore, we investigated the CD74 expression in clear cell renal cell carcinoma (ccRCC). Immunohistochemistry of CD74 indicated that CD74 was expressed not only in cancer cells but also macrophages. CD74 was detected in surface membrane and cytoplasm of cancer cells in 92 of 94 cases (98%) and of 87 of 94 cases (93%). CD74 was expressed both in cancer cells and TAMs in 86 of 94 cases (91%). In vitro studies using cancer cell lines and monocyte-derived macrophages stimulated by anti-CD74 antibodies showed that CD74 signal accelerated cancer cell proliferation and macrophage activation. However, macrophage activation via CD74 signal did not influence macrophage-mediated cancer cell growth. RNA-sequence of macrophages stimulated by anti-CD74 antibodies indicated that CD74 signal was associated to inflammatory responses in macrophages. In conclusion, we examined the expression and functional significance of CD74 in ccRCC using tissue specimens and cell culture studies. The function of CD74 was suggested to be different in cancer cells and in macrophages, and further studies are necessary to clarify the functional significance of CD74 in ccRCC.

Presence of Fusobacterium nucleatum in relation to patient survival and an acidic environment in oesophagogastric junction and gastric cancers.

BACKGROUND: Fusobacterium nucleatum inhabits the oral cavity and affects the progression of gastrointestinal cancer. Our prior findings link F. nucleatum to poor prognosis in oesophageal squamous cell carcinoma via NF-κB pathway. However, its role in oesophagogastric junction and gastric adenocarcinoma remains unexplored. We investigated whether F. nucleatum influences these cancers, highlighting its potential impact. METHODS: Two cohorts of EGJ and gastric adenocarcinoma patients (438 from Japan, 380 from the USA) were studied. F. nucleatum presence was confirmed by qPCR, FISH, and staining. Patient overall survival (OS) was assessed based on F. nucleatum positivity. EGJ and gastric adenocarcinoma cell lines were exposed to F. nucleatum to study molecular and phenotypic effects, validated in xenograft mouse model. RESULTS: In both cohorts, F. nucleatum-positive EGJ or gastric adenocarcinoma patients had notably shorter OS. F. nucleatum positivity decreased in more acidic tumour environments. Cancer cell lines with F. nucleatum showed enhanced proliferation and NF-κB activation. The xenograft model indicated increased tumour growth and NF-κB activation in F. nucleatum-treated cells. Interestingly, co-occurrence of F. nucleatum and Helicobacter pylori, a known risk factor, was rare. CONCLUSIONS: F. nucleatum can induce the NF-κB pathway in EGJ and gastric adenocarcinomas, leading to tumour progression and poor prognosis.

Impacts of cytoplasmic p53 aggregates on the prognosis and the transcriptome in lung squamous cell carcinoma.

The tumor suppressor TP53 gene, the most frequently mutated gene in human cancers, produces the product tumor protein p53, which plays an essential role in DNA damage. p53 protein mutations may contribute to tumorigenesis by loss of tumor suppressive functions and malignancy of cancer cells via gain-of-oncogenic functions. We previously reported that mutant p53 proteins form aggregates and that cytoplasmic p53 aggregates were associated with poor prognosis in human ovarian cancer. However, the prognostic impact of p53 aggregation in other tumors including lung squamous cell carcinoma (SCC) is poorly understood. Here, we demonstrated that lung SCC cases with cytoplasmic p53 aggregates had a significantly poor clinical prognosis. Analysis via patient-derived tumor organoids (PDOs) established from lung SCC patients and possessing cytoplasmic p53 aggregates showed that eliminating cytoplasmic p53 aggregates suppressed cell proliferation. RNA sequencing and transcriptome analysis of p53 aggregate-harboring PDOs indicated multiple candidate pathways involved in p53 aggregate oncogenic functions. With lung SCC-derived cell lines, we found that cytoplasmic p53 aggregates contributed to cisplatin resistance. This study thus shows that p53 aggregates are a predictor of poor prognosis in lung SCC and suggests that detecting p53 aggregates via p53 conventional immunohistochemical analysis may aid patient selection for platinum-based therapy.

TRMT10A dysfunction perturbs codon translation of initiator methionine and glutamine and impairs brain functions in mice.

In higher eukaryotes, tRNA methyltransferase 10A (TRMT10A) is responsible for N1-methylguanosine modification at position nine of various cytoplasmic tRNAs. Pathogenic mutations in TRMT10A cause intellectual disability, microcephaly, diabetes, and short stature in humans, and generate cytotoxic tRNA fragments in cultured cells; however, it is not clear how TRMT10A supports codon translation or brain functions. Here, we generated Trmt10a null mice and showed that tRNAGln(CUG) and initiator methionine tRNA levels were universally decreased in various tissues; the same was true in a human cell line lacking TRMT10A. Ribosome profiling of mouse brain revealed that dysfunction of TRMT10A causes ribosome slowdown at the Gln(CAG) codon and increases translation of Atf4 due to higher frequency of leaky scanning of its upstream open reading frames. Broadly speaking, translation of a subset of mRNAs, especially those for neuronal structures, is perturbed in the mutant brain. Despite not showing discernable defects in the pancreas, liver, or kidney, Trmt10a null mice showed lower body weight and smaller hippocampal postsynaptic densities, which is associated with defective synaptic plasticity and memory. Taken together, our study provides mechanistic insight into the roles of TRMT10A in the brain, and exemplifies the importance of universal tRNA modification during translation of specific codons.

Tumor-associated macrophages: The key player in hepatoblastoma microenvironment and the promising therapeutic target.

The tumor microenvironment of hepatoblastoma (HB), the most common pediatric liver tumor, predominantly exhibits a myeloid immune landscape. in which tumor-associated macrophages (TAMs) are considered the core component. The crosstalk between TAMs and HB cells markedly influences tumor behavior. TAM-derived factors are involved in tumor proliferation and vascular invasion. On the other hand, HB cell secretome attracts, stimulates, and reprograms TAMs to be immunosuppressive in favor of tumor invasion, rather than their innate role in combating tumor growth, such crosstalk sometimes forms bidirectional feedback loops, making the tumor more virulent and resistant to routine therapeutics. Consequently, TAMs are the common denominator of most suggested HB immunotherapeutic strategies. Macrophage immune checkpoint inhibitors, macrophage-mediated antibody-dependent cellular phagocytosis, and the novel chimeric antigen receptor macrophage therapy (CAR Mφ) are currently under trial. In this review, we will summarize the significance of TAMs and their potential role as a therapeutic target in HB.

Anticancer immune reaction and lymph node sinus macrophages: a review from human and animal studies.

Lymph nodes are secondary lymphoid organs localized throughout the body that typically appear as bean-like nodules. Numerous antigen-presenting cells, including dendritic cells and macrophages, that mediate host defense responses against pathogens, such as bacteria and viruses, reside within lymph nodes. To react to cancer cell-derived antigens in a variety of cancers, antigen-presenting cells induce cytotoxic T lymphocytes (CTLs). In relation to anticancer immune responses, macrophages in the lymph node sinus have been of particular interest because a number of studies involving both human specimens and animal models have reported that lymph node macrophages expressing CD169 play a key role in activating anticancer CTLs. Recent studies have indicated that dysfunction of lymph node macrophages potentially contributes to immune suppression in elderly patients and immunological "cold" tumors. Therefore, in anticancer therapy, the regulation of lymph node macrophages is a potentially promising approach.

Enhanced systemic antitumor efficacy of PD-1/PD-L1 blockade with immunological response induced by photodynamic therapy.

BACKGROUND: Photodynamic therapy (PDT) is an antitumor therapy and has traditionally been regarded as a localized therapy in itself. However, recent reports have shown that it not only exerts a direct cytotoxic effect on cancer cells but also enhances body's tumor immunity. We hypothesized that the immunological response induced by PDT could potentially enhance the efficacy of programmed death-1 (PD-1) / programmed death-ligand 1 (PD-L1) blockade. METHODS: The cytotoxic effects of PDT on colon 26 cells were investigated in vitro using the WST assay. We investigated whether the antitumor effect of anti-PD-1 antibodies could be amplified by the addition of PDT. We performed combination therapy by randomly allocating tumor-bearing mice to four treatment groups: control, anti-PD-1 antibodies, PDT, and a combination of anti-PD-1 antibodies and PDT. To analyze the tumor microenvironment after treatment, the tumors were resected and pathologically evaluated. RESULTS: The viability rate of colon 26 cells decreased proportionally with the laser dose. In vivo experiments for combined PDT and anti-PD-1 antibody treatment, combination therapy showed an enhanced antitumor effect compared with the control. Immunohistochemical findings of the tumor microenvironment 10 days after PDT indicated that the number of CD8+ cells, the area of Iba-1+ cells and the area expressing PD-L1 were significantly higher in tumors treated with combination therapy than in tumors treated with anti-PD-1 antibody alone, PDT alone, or the control. CONCLUSIONS: PDT increased immune cell infiltration into the tumor microenvironment. The immunological response induced by PDT may enhance the efficacy of PD-1/PD-L1 blockade.

Proton Pump Inhibitor Associated Multiple Gastric Hyperplastic Polyps With Uncontrollable Bleeding: A Case Report.

BACKGROUND/AIM: The long-term use of proton pump inhibitors (PPIs) has been reported to be strongly associated with the development of fundic gland polyps (FGPs). Conversely, a few cases of gastric hyperplastic polyps (GHPs) associated with PPI use have been reported. We experienced a case of PPI-associated multiple GHPs with uncontrollable bleeding. CASE REPORT: A 64 year old man with a history of rheumatoid arthritis presented to the hospital with complaints of vertigo and black stools. Blood tests revealed anemia and hypoproteinemia. Esophagogastroduodenoscopy (EGD) showed blood and black residue accumulated in the stomach. The source of the bleeding was multiple hyperplastic polyps. Bleeding could be stopped even with fasting, and total blood transfusions amounted to 28 units of RBCs were required in 18 days. After the cessation of PPI, EGD showed that the polyps had almost disappeared. Pathological diagnosis of resected polyp was hyperplastic polyp, which was characterized by capillary hyperplasia and edema. Gastrin receptors were over-expressed in the foveolar epithelium and not in the capillaries. Methotrexate (MTX)-induced portal hypertensive gastroenteropathy was revealed during follow-up. We consider that the effect of portal hypertension may have caused the capillary hyperplasia. CONCLUSION: Although PPI-related polyps are usually fundic gland polyps and do not cause life-threatening adverse events, we experienced PPI-related GHPs in which hemostasis was difficult to control.

Age-associated reduction of sinus macrophages in human mesenteric lymph nodes.

There are numerous macrophages and dendritic cells in lymph nodes (LNs). Recent studies have highlighted that sinus macrophages (SMs) in LNs possess antigen-presenting capabilities and are related to anti-cancer immune responses. In this study, we assessed the distribution of SMs in mesenteric LNs removed during surgery for colorectal cancer. A marked reduction of SMs was noted in elderly patients, particularly those over 80 years old. We observed a disappearance of CD169-positive cells in LNs where SMs were reduced. In silico analysis of publicly available single-cell RNA sequencing data from LNs revealed that CD169-positive macrophages express numerous genes associated with antigen presentation and lymphocyte proliferation, similar to dendritic cells' functions. In conclusion, our study demonstrates that SMs, potentially crucial for immune activation, diminish in the LNs of elderly patients. This reduction of SMs may contribute to the immune dysfunction observed in the elderly.

A Case of Aggressive Lung Squamous Cell Carcinoma With Aberrant Cytoplasmic p53 Aggregation.

Background: Immunohistochemistry for p53 was a well-established method for cancer diagnosis in pathology. Aberrant cytoplasmic p53 positivity reflects the accumulation of p53 aggregates, which has been shown to be associated with chemoresistance and to be a predictive marker of a worse clinical course in ovarian cancer. Case Report: A 65-year-old Japanese man was diagnosed with lung cancer, and surgical resection was performed. Multiple metastasis were found 21 months post-surgery. The lesions were resistant to chemotherapy, and he succumbed to the disease 29 months post-surgery. The resected primary lesion was pathologically diagnosed as squamous cell carcinoma, with notable cytoplasmic p53 positivity indicated by immunohistochemistry. Conclusion: Notable aberrant cytoplasmic accumulation of p53 aggregate was observed in the cancer cells of this case. Chemotherapy was ineffective for the recurrent lesions, suggesting a role of p53 aggregates in chemoresistance. Pathological analysis of p53 via immunohistochemistry may be useful in predicting chemoresistance of lung squamous cell carcinoma.

Gastric Small Cell Neuroendocrine Carcinoma With Loss of Epithelial Markers Expression.

Background/Aim: Given that gastric small cell neuroendocrine carcinoma (SCNEC) is notably more aggressive than conventional adenocarcinoma, and a platinum-based regimen aligned with the treatment for pulmonary SCNEC is advocated when chemotherapy is needed, ensuring an accurate pathological diagnosis is paramount. Case Report: A 63-year-old man, examined for melena, underwent gastroscopy which revealed a total circumferential Borrmann type 3 lesion extending from the pylorus to the antrum of the stomach. He underwent a distal gastrectomy with D2 lymphadenectomy. The microscopic examination revealed SCNEC with a minor adenocarcinoma component. Immunohistochemically, the SCNEC was diffusely positive for synaptophysin, CD56, and INSM1, very focally positive for chromogranin A, and negative for leukocyte common antigen, CD3, and CD20. A significant observation in this case was the complete negativity for epithelial markers including keratin (CK7, CK8, CK20, CAM5.2, and AE1/AE3) and epithelial membrane antigen. Conclusion: Diffuse positivity for neuroendocrine markers, negativity for other lineage markers, and a transition from the adenocarcinoma component, if present, serve as significant diagnostic clues for gastric SCNEC with loss of epithelial markers expression. SCNEC should not be excluded solely based on the negative result for epithelial markers.

Pivotal role of IL-8 derived from the interaction between osteosarcoma and tumor-associated macrophages in osteosarcoma growth and metastasis via the FAK pathway.

The prognosis of osteosarcoma (OS) has remained stagnant over the past two decades, requiring the exploration of new therapeutic targets. Cytokines, arising from tumor-associated macrophages (TAMs), a major component of the tumor microenvironment (TME), have garnered attention owing to their impact on tumor growth, invasion, metastasis, and resistance to chemotherapy. Nonetheless, the precise functional role of TAMs in OS progression requires further investigation. In this study, we investigated the interaction between OS and TAMs, as well as the contribution of TAM-produced cytokines to OS advancement. TAMs were observed to be more prevalent in lung metastases compared with that in primary tumors, suggesting their potential support for OS progression. To simulate the TME, OS and TAMs were co-cultured, and the cytokines resulting from this co-culture could stimulate OS proliferation, migration, and invasion. A detailed investigation of cytokines in the co-culture conditioned medium (CM) revealed a substantial increase in IL-8, establishing it as a pivotal cytokine in the process of enhancing OS proliferation, migration, and invasion through the focal adhesion kinase (FAK) pathway. In an in vivo model, co-culture CM promoted OS proliferation and lung metastasis, effects that were mitigated by anti-IL-8 antibodies. Collectively, IL-8, generated within the TME formed by OS and TAMs, accelerates OS proliferation and metastasis via the FAK pathway, thereby positioning IL-8 as a potential novel therapeutic target in OS.

Hypoxia-related carbonic anhydrase 9 induces serpinB9 expression in cancer cells and apoptosis in T cells via acidosis.

Hypoxia is a common feature of solid tumors. However, the impact of hypoxia on immune cells within tumor environments remains underexplored. Carbonic anhydrase 9 (CA9) is a hypoxia-responsive tumor-associated enzyme. We previously noted that regardless of human CA9 (hCA9) expression, hCA9-expressing mouse renal cell carcinoma RENCA (RENCA/hCA9) presented as a "cold" tumor in syngeneic aged mice. This study delves into the mechanisms behind this observation. Gene microarray analyses showed that RENCA/hCA9 cells exhibited elevated mouse serpinB9, an inhibitor of granzyme B, relative to RENCA cells. Corroborating this, RENCA/hCA9 cells displayed heightened resistance to antigen-specific cytotoxic T cells compared with RENCA cells. Notably, siRNA-mediated serpinB9 knockdown reclaimed this sensitivity. In vivo tests showed that serpinB9 inhibitor administration slowed RENCA tumor growth, but this effect was reduced in RENCA/hCA9 tumors, even with adjunctive immune checkpoint blockade therapy. Further, inducing hypoxia or introducing the mouse CA9 gene upregulated serpinB9 expression, and siRNA-mediated knockdown of the mouse CA9 gene inhibited the hypoxia-induced induction of serpinB9 in the original RENCA cells. Supernatants from RENCA/hCA9 cultures had lower pH than those from RENCA, suggesting acidosis. This acidity enhanced serpinB9 expression and T cell apoptosis. Moreover, coculturing with RENCA/hCA9 cells more actively prompted T cell apoptosis than with RENCA cells. Collectively, these findings suggest hypoxia-associated CA9 not only boosts serpinB9 in cancer cells but also synergistically intensifies T cell apoptosis via acidosis, characterizing RENCA/hCA9 tumors as "cold."

IL-32 production from lung adenocarcinoma cells is potentially involved in immunosuppressive microenvironment.

Interleukin 32 (IL-32) is a proinflammatory cytokine secreted from several kinds of cancer cells. In the present study, we investigated the significance of IL-32 in lung adenocarcinoma by immunohistochemistry and bioinformatics analysis. IL-32 was positive in cancer cells of 21 cases (9.2%) of total 228 cases. Increased IL-32 gene expression was linked to worse clinical course in TCGA analysis, however, IL-32 expression in immunohistochemistry was not associated to clinical course in our cohort. It was also found that high IL-32 expression was seen in cases with increased lymphocyte infiltration. In vitro studies indicated that IFN-γ induced gene expression of IL-32 and PD1-ligands in lung adenocarcinoma cell lines. IL-32, especially IL-32ß, also induced overexpression of PD1-ligands in human monocyte-derived macrophages. Additionally, Cancer-cell-derived IL-32 was elevated by stimulation with anticancer agents. In conclusion, IL-32 potentially induced by inflammatory conditions and anticancer therapy and contribute to immune escape of cancer cells via development the immunosuppressive microenvironment. IL-32 might be a target molecule for anti-cancer therapy.

The expression analysis of SerpinB9 in hepatoblastoma microenvironment.

PURPOSE: In this research, we analyzed the expression of serpinB9 in hepatoblastoma and investigated the factors which enhance its expression. METHOD: SerpinB9 expression in hepatoblastoma cell lines and macrophages co-cultured with each other or stimulated by anticancer agents was examined using RT-qPCR and western blotting. Immunohistochemistry for SerpinB9 in hepatoblastoma specimens was performed. Single-cell RNA-sequence data for hepatoblastoma from an online database were analyzed to investigate which types of cells express SerpinB9. RESULT: HepG2, a hepatoblastoma cell line, exhibited increased expression of SerpinB9 when indirectly co-cultured with macrophages. Immunohistochemistry for the specimens demonstrated that serpinB9 is positive not in hepatoblastoma cells but in macrophages. Single-cell RNA sequence analysis in tissues from hepatoblastoma patients showed that macrophages expressed SerpinB9 more than tumor cells did. Co-culture of macrophages with hepatoblastoma cell lines led to the enhanced expression of SerpinB9 in both macrophages and cell lines. Anticancer agents induced an elevation of SerpinB9 in hepatoblastomas cell lines. CONCLUSION: In hepatoblastoma, SerpinB9 is thought to be more highly expressed in macrophages and enhanced by interaction with hepatoblastoma cell.

Fluoride-treated rare earth-free magnesium alloy ZK30: An inert and bioresorbable material for bone fracture treatment devices.

Bone fractures represent a common health problem, particularly in an increasingly aging population. Bioresorbable magnesium (Mg) alloy-based implants offer promising alternatives to traditional metallic implants for the treatment of bone fractures because they eliminate the need for implant removal after healing. The Mg-Y-rare-earth (RE)-Zr alloy WE43, designed for orthopedic implants, has received European Conformity mark approval. However, currently, WE43 is not clinically used in certain countries possibly because of concerns related to RE metals. In this study, we investigated the use of a RE-free alloy, namely, Mg-Zn-Zr alloy (ZK30), as an implant for bone fractures. Hydrofluoric acid (HF) treatment was performed to improve the corrosion resistance of ZK30. HF-treated ZK30 (HF-ZK30) exhibited lower corrosion rate and higher biocompatibility than those of WE43 in in vitro experiments. After implanting a rod of HF-ZK30 into the fractured femoral bones of mice, HF-ZK30 held the bones and healed the fracture without deformation. Treatment results of HF-ZK30 were comparable to those of WE43, indicating the potential of HF-ZK30 as a bioresorbable and safe implant for bone repair.