Synergistic antitumor activity by dual blockade of CCR1 and CXCR2 expressed on myeloid cells within the tumor microenvironment.

BACKGROUND: Chemokine signaling within the tumor microenvironment can promote tumor progression. Although CCR1 and CXCR2 on myeloid cells could be involved in tumor progression, it remains elusive what effect would be observed if both of those are blocked. METHODS: We employed two syngeneic colorectal cancer mouse models: a transplanted tumor model and a liver metastasis model. We generated double-knockout mice for CCR1 and CXCR2, and performed bone marrow (BM) transfer experiments in which sub-lethally irradiated wild-type mice were reconstituted with BM from either wild-type, Ccr1-/-, Cxcr2-/- or Ccr1-/-Cxcr2-/- mice. RESULTS: Myeloid cells that express MMP2, MMP9 and VEGF were accumulated around both types of tumors through CCR1- and CXCR2-mediated pathways. Mice reconstituted with Ccr1-/-Cxcr2-/- BM exhibited the strongest suppression of tumor growth and liver metastasis compared with other three groups. Depletion of CCR1+CXCR2+ myeloid cells led to a higher frequency of CD8+ T cells, whereas the numbers of Ly6G+ neutrophils, FOXP3+ Treg cells and CD31+ endothelial cells were significantly decreased. Furthermore, treatment with a neutralizing anti-CCR1 mAb to mice reconstituted with Cxcr2-/- BM significantly suppressed tumor growth and liver metastasis. CONCLUSION: Dual blockade of CCR1 and CXCR2 pathways in myeloid cells could be an effective therapy against colorectal cancer.

Successful treatment of severe splenic lymphoma­associated hemophagocytic syndrome by splenectomy and subsequent chemotherapy: A case report.

Hemophagocytic lymphohistiocytosis (HLH) represents a fatal immunopathology derived from excessive inflammatory reactions. In particular, lymphoma-associated hemophagocytic syndrome (LAHS) is associated with a dismal prognosis. The current study presented a challenging case of splenic LAHS. A 71-year-old man presented with fatigue and anorexia. Laboratory test results revealed anemia, thrombocytopenia, lactate dehydrogenase elevation and markedly elevated levels of ferritin (6,210 ng/ml) and soluble interleukin 2 receptor (sIL-2R; 11,328 U/ml). Abdominal computed tomography revealed marked splenomegaly, while fluorodeoxyglucose positron emission tomography revealed increased tracer uptake in the spleen. An elective splenectomy was performed, which led to the diagnosis of B-cell splenic lymphoma with transformation from indolent to aggressive lymphoma. Prior to the splenectomy, thrombocytopenia and hepatic dysfunction with rapidly progressing jaundice appeared, accompanying further elevation of ferritin (25,197 ng/ml) and sIL-2R levels (30,420 U/ml). On postoperative day 5, the patient was transferred to a tertiary care institution and corticosteroid pulse therapy was immediately initiated after establishing the diagnosis of LAHS. Liver dysfunction gradually recovered and subsequent chemotherapy resulted in complete remission with improved performance status. At eight months after the onset, the patient remains alive without any signs of residual lymphoma. Although splenic lymphoma typically manifests with low-grade lymphoma, it can transform into high-grade lymphoma associated with severe complications, such as HLH and multiple organ failure. In this case, splenectomy assisted in not only establishing the diagnosis but also in tumor cytoreduction before commencing chemotherapy. Through interdisciplinary collaboration, the patient was successfully treated by performing a timely splenectomy, followed by steroid pulse therapy and chemotherapy.

A surgical case of anti-coagulant ileus mimicking small-bowel tumors: a case report.

BACKGROUND: Anti-coagulant ileus, characterized by intramural hematoma due to excessive anti-coagulant therapy, presents a diagnostic challenge. Although previously considered uncommon, recently, reporting cases of anti-coagulant ileus have become more frequent. Herein, we report a rare surgical case of anti-coagulant ileus mimicking small-bowel tumors. CASE PRESENTATION: A 79-year-old man was admitted to our hospital for fatigue. He had been administered warfarin for 5 months for atrial fibrillation. On admission, the patient exhibited mild epigastric tenderness. Laboratory test results revealed anemia (hemoglobin, 8.4 g/dL); unmeasurably prolonged prothrombin time (PT) with international normalized ratio (INR) > 8; and elevated soluble interleukin 2 receptor (sIL-2R) levels (849 IU/mL; normal range, 122-496 IU/mL). Abdominal plain computed tomography (CT) showed a circumferentially thickened intestinal wall at one site in the jejunum and two in the ileum. After hospitalization, bowel obstruction did not improve with conservative treatment. Suspecting small-bowel tumors such as lymphoma, the patient subsequently underwent open surgery on day 3 after admission. No obvious tumor mass was observed intra-operatively. However, only thickened and hemorrhagic segments were identified at the suspected sites. We performed partial jejunal and ileal resections of 12 and 27 cm, respectively. Histopathology confirmed submucosal congestion, edema, and hemorrhage in each area without tumor components, leading to the final diagnosis of intramural hematoma. The postoperative course was uneventful, and he was discharged on postoperative day 9. No recurrence occurred during the 5-year follow-up period. CONCLUSIONS: We encountered a surgical case of anti-coagulant ileus, which was difficult to differentiate from malignant lymphoma based on CT findings and high sIL-2R levels. The possibility of anti-coagulant ileus should always be considered in patients on long-term anticoagulation medication and bowel obstruction with high PT-INR values.

Downregulation of osteoprotegerin in colorectal cancer cells promotes liver metastasis via activating tumor-associated macrophage.

Osteoprotegerin (OPG) is a secreted cytokine that functions as a decoy receptor for receptor activator of nuclear factor kappa-B (RANK) ligand (RANKL). Anti-RANKL treatment for bone metastasis has been widely accepted for solid tumors. However, the mechanism of OPG-RANKL-RANK signaling in systemic colorectal cancer (CRC) metastasis remains unclear. In this study, we investigated the relevance and function of OPG expression in CRC liver metastasis. First, we performed in silico analysis using The Cancer Genome Atlas public database and found that lower OPG expression in CRC was associated with poor overall survival. Immunohistochemistry analyses using resected specimen from patients with CRC in our institute confirmed the result. Patient-matched primary CRC and liver metastases showed a significant downregulation of OPG expression in metastatic lesions. In CRC cell lines, OPG expression did not suppress cell proliferation and migration. However, OPG expression inhibited macrophage migration by suppressing the RANKL-RANK pathway. Moreover, in vivo mouse liver metastasis models showed that OPG expression in CRC cells suppressed liver metastases. In addition, treatment with an anti-RANKL neutralizing antibody also suppressed liver metastases. These results showed that downregulation of OPG expression in CRC cells promotes liver metastasis by activating tumor-associated macrophage, which can become a candidate for targeted therapy with anti-RANKL neutralizing antibody for CRC liver metastasis.

Neutrophil Extracellular Traps Promote Metastases of Colorectal Cancers through Activation of ERK Signaling by Releasing Neutrophil Elastase.

Neutrophil extracellular traps (NETs) play important roles in host immunity, as there is increasing evidence of their contribution to the progression of several types of cancers even though their role in colorectal cancers (CRCs) remains unclear. To investigate the clinical relevance of NETs in CRCs, we examined the expression of citrullinated histone H3 using immunohistochemistry and preoperative serum myeloperoxidase-DNA complexes in CRC patients using an enzyme-linked immunosorbent assay. High expression of intratumoral or systemic NETs was found to correlate with poor relapse-free survival (RFS), for which it is an independent prognostic factor. In vitro investigations of CRC cells (HCT116, HT29) revealed that NETs did not affect their proliferation but did promote the migration of CRC cells mediated by neutrophil elastase (NE) released during NETosis to increase extracellular signal-regulated kinase (ERK) activity. In vivo experiments using nude mice (KSN/slc) revealed that NE inhibition suppressed liver metastases in CRC cells, although it did not affect the growth of subcutaneously implanted tumors. Taken together, these results suggest that NET formation correlates with poor prognoses of patients with CRC and that the inhibition of NE could be a potential therapy for CRC metastases.

Dual blockade of macropinocytosis and asparagine bioavailability shows synergistic anti-tumor effects on KRAS-mutant colorectal cancer.

Mutations of KRAS gene are found in various types of cancer, including colorectal cancer (CRC). Despite intense efforts, no pharmacological approaches are expected to be effective against KRAS-mutant cancers. Macropinocytosis is an evolutionarily conserved actin-dependent endocytic process that internalizes extracellular fluids into large vesicles called macropinosomes. Recent studies have revealed macropinocytosis's important role in metabolic adaptation to nutrient stress in cancer cells harboring KRAS mutations. Here we showed that KRAS-mutant CRC cells enhanced macropinocytosis for tumor growth under nutrient-depleted conditions. We also demonstrated that activation of Rac1 and phosphoinositide 3-kinase were involved in macropinocytosis of KRAS-mutant CRC cells. Furthermore, we found that macropinocytosis was closely correlated with asparagine metabolism. In KRAS-mutant CRC cells engineered with knockdown of asparagine synthetase, macropinocytosis was accelerated under glutamine-depleted condition, and albumin addition could restore the glutamine depletion-induced growth suppression by recovering the intracellular asparagine level. Finally, we discovered that the combination of macropinocytosis inhibition and asparagine depletion dramatically suppressed the tumor growth of KRAS-mutant CRC cells in vivo. These results indicate that dual blockade of macropinocytosis and asparagine bioavailability could be a novel therapeutic strategy for KRAS-mutant cancers.

Disruption of CCR1-mediated myeloid cell accumulation suppresses colorectal cancer progression in mice.

Tumor-stromal interaction is implicated in tumor progression. Although CCR1 expression in myeloid cells could be associated with pro-tumor activity, it remains elusive whether disruption of CCR1-mediated myeloid cell accumulation can suppress tumor progression. Here, we investigated the role of CCR1 depletion in myeloid cells in two syngeneic colorectal cancer mouse models: MC38, a transplanted tumor model and CMT93, a liver metastasis model. Both cells induced tumor accumulation of CCR1+ myeloid cells that express MMP2, MMP9, iNOS, and VEGF. Lack of the Ccr1 gene in host mice dramatically reduced MC38 tumor growth as well as CMT93 liver metastasis. To delineate the contribution of CCR1+ myeloid cells, we performed bone marrow (BM) transfer experiments in which sub-lethally irradiated wild-type mice were reconstituted with BM from either wild-type or Ccr1-/- mice. Mice reconstituted with Ccr1-/- BM exhibited marked suppression of MC38 tumor growth and CMT93 liver metastasis, compared with control mice. Consistent with these results, administration of a neutralizing anti-CCR1 monoclonal antibody, KM5908, significantly suppressed MC38 tumor growth and CMT93 liver metastases. Our findings highlight the importance of the application of CCR1 blockade as a therapeutic strategy.

The preventive surgical site infection bundle in patients with colorectal perforation.

BACKGROUND: Incisional surgical site infection (SSI) is one of the most frequent complications that occur after colorectal surgery. Surgery for colorectal perforation carries an especially high risk of incisional SSI because fecal ascites contaminates the incision intraoperatively, and in patients who underwent stoma creation, the incision is located near the infective origin and is subject to infection postoperatively. Although effectiveness of the preventive SSI bundle of elective colorectal surgery has been reported, no study has focused exclusively on emergency surgery for colorectal perforation. METHODS: Patients with colorectal perforation who underwent emergency surgery and stoma creation from 2010 to 2015 at our center were consecutively enrolled in the study. In March 2013, we developed the preventive incisional SSI bundle for patients with colorectal perforation undergoing stoma creation. The effectiveness of the bundle in these patients was determined and the rates of incisional SSI between before and after March 2013 were compared. RESULTS: We enrolled 108 patients with colorectal perforation who underwent emergency operation during the study period. Thirteen patients were excluded because they died within 30 days after surgery, and 23 patients without stoma were excluded; thus, 72 patients were analyzed. There were 47 patients in the pre-implementation group and 25 patients in the post-implementation group. The rate of incisional SSI was significantly lower after implementation of preventive incisional SSI bundle (43% vs. 20%, p = 0.049). Postoperative hospital stay was significantly shorter after implementation of the bundle (27 vs. 18 days respectively; p = 0.008). CONCLUSIONS: The preventive incisional SSI bundle was effective in preventing incisional SSI in patients with colorectal perforation undergoing emergency surgery with stoma creation.

Prediction of mortality in patients with colorectal perforation based on routinely available parameters: a retrospective study.

INTRODUCTION: Even after surgery and intensive postoperative management, the mortality rate associated with colorectal perforation is high. Identification of mortality markers using routinely available preoperative parameters is important. METHODS: We enrolled consecutive patients with colorectal perforation who underwent operations from January 2010 to January 2015. We divided them into a mortality and survivor group and compared clinical characteristics between the two groups. Additionally, we compared the mortality rate between different etiologies: malignant versus benign and diverticular versus nondiverticular. We used the χ (2) and Mann-Whitney U tests and a logistic regression model to identify factors associated with mortality. RESULTS: We enrolled 108 patients, and 52 (48 %) were male. The mean age at surgery was 71 ± 13 years. The postoperative mortality rate was 12 % (13 patients). Multivariate logistic regression analysis showed that a high patient age (odds ratio [OR], 1.09; 95 % confidence interval [CI], 1.020-1.181) and low preoperative systolic blood pressure (OR, 0.98; 95 % CI, 0.953-0.999) were independent risk factors for mortality in patients with colorectal perforation. In the subgroup analysis, there was no significant difference between the malignant and benign group (11.8 % vs. 23.9 %, respectively; p = 0.970), while the diverticular group had a significantly lower mortality rate than the nondiverticular group (2.6 % vs. 17.1 %, respectively; p = 0.027). CONCLUSIONS: Older patients and patients with low preoperative blood pressure had a high risk of mortality associated with colorectal perforation. For such patients, operations and postoperative management should be performed carefully.

Comparison between anatomical subsegmentectomy and nonanatomical partial resection for hepatocellular carcinoma located within a single subsegment: a single-center retrospective analysis.

BACKGROUND/AIMS: For hepatocellular carcinoma (HCC) within a single subsegment, the superiority of anatomical subsegmentectomy over non-anatomical partial resection is still controversial. In this study, we assessed the potential benefit of subsegmentectomy. METHODOLOGY: We selected 44 patients with a single HCC lesion within one subsegment who had undergone anatomical subsegmentectomy or non-anatomical partial resection from among 173 patients who underwent hepatectomy in our hospital from August 2003 to May 2013. We compared the results following anatomical subsegmentectomy (Group A; n = 16) and non-anatomical partial resection (Group N; n = 28). RESULTS: One- and two-year survival rates were 92.5% and 89.3%, respectively; 1- and 2-year recurrence-free survival (RFS) rates were 88.9% and 69.1%, respectively. There was no significant difference in overall survival or RFS between the groups. However, among HBV-positive patients, RFS was significantly better for Group A than Group N (p = 0.008). CONCLUSIONS: For HBV-positive HCC within a single subsegment, we recommend subsegmentectomy.