A Novel Combination Cancer Therapy with Iron Chelator Targeting Cancer Stem Cells via Suppressing Stemness.

Excess iron causes cancer and is thought to be related to carcinogenesis and cancer progression including stemness, but the details remain unclear. Here, we hypothesized that stemness in cancer is related to iron metabolism and that regulating iron metabolism in cancer stem cells (CSCs) may be a novel therapy. In this study, we used murine induced pluripotent stem cells that expressed specific stem cell genes such as Nanog, Oct3/4, Sox2, Klf4, and c-Myc, and two human cancer cell lines with similar stem cell gene expression. Deferasirox, an orally available iron chelator, suppressed expression of stemness markers and spherogenesis of cells with high stemness status in vitro. Combination therapy had a marked antitumor effect compared with deferasirox or cisplatin alone. Iron metabolism appears important for maintenance of stemness in CSCs. An iron chelator combined with chemotherapy may be a novel approach via suppressing stemness for CSC targeted therapy.

Cancer-associated fibroblasts (CAFs) promote the lymph node metastasis of esophageal squamous cell carcinoma.

Lymph node metastasis is a pathognomonic feature of spreading tumors, and overcoming metastasis is a challenge in attaining more favorable clinical outcomes. Esophageal cancer is an aggressive tumor for which lymph node metastasis is a strong poor prognostic factor, and the tumor microenvironment (TME), and cancer-associated fibroblasts (CAFs) in particular, has been implicated in esophageal cancer progression. CAFs play a central role in the TME and have been reported to provide suitable conditions for the progression of esophageal cancer, similar to their role in other malignancies. However, little is known concerning the relevance of CAFs to the lymph node metastasis of esophageal cancer. Here, we used clinical samples of esophageal cancer to reveal that CAFs promote lymph node metastasis and subsequently verified the intercellular relationships in vitro and in vivo using an orthotopic metastatic mouse model. In the analysis of clinical samples, FAP+ CAFs were strongly associated with lymph node metastasis rather than with other prognostic factors. Furthermore, CAFs affected the ability of esophageal cancer cells to acquire metastatic phenotypes in vitro; this finding was confirmed by data from an in vivo orthotopic metastatic mouse model showing that the number of lymph node metastases increased upon injection of cocultured cancer cells and CAFs. In summary, we verified in vitro and in vivo that the accumulation of CAFs enhances the lymph node metastasis of ESCC. Our data suggest that CAF targeted therapy can reduce lymph node metastasis and improve the prognosis of patients with esophageal cancer in the future.

[The Elucidation of Tumor Immunosuppression Affected by Cancer-Associated Fibroblasts].

Development of immunotherapy, especially checkpoint inhibitors, dramatically improved the prognosis of some malignancies. However, problems on the occurrence of severe adverse effects and limited responses to these checkpoint inhibitors remain. Recently, tumor infiltrating lymphocytes(TILs)are the predictive markers of immunotherapies based on clinical evidence. The proportion of cytotoxic T cells in the tumor has been reported to affect the antitumor effect. TILs in the tumor are thought to be controlled by the interaction between cancer and tumor microenvironment. As a cause of tumor immunosuppression, cancer-associated fibroblasts(CAFs)play the main role in the tumor microenvironment. We considered the strong involvement of tumor microenvironment, particularly the role of CAFs, and reported the interaction between CAFs and proliferation, invasion, angiogenesis, and resistance in the conventional therapy. The correlation between CAFs and tumor immunity and the immunosuppression promoted by CAFs were also evaluated. Their effects will be reported in our future studies.

Clinical characteristics and management of gastric tube cancer after esophagectomy.

BACKGROUND: Gastric cancer is the second most common malignancy, overlapping with thoracic esophageal cancer (TEC). Among them, metachronous gastric tube cancers after TEC surgery have been increasing. The aims of this study were to examine the clinicopathological factors and treatment outcomes of gastric tube cancer (GTC) after TEC surgery. METHODS: Thirty-three GTCs in 30 cases after TEC treated between 1997 and 2016 were investigated retrospectively. RESULTS: Most cases were males. The median interval from TEC surgery to GTC occurrence was 57 (6.5-107.5) months. Almost 2/3 lesions occurred in the lower third of the gastric tube (21/33); 29 lesions (in 26 cases) were superficial cancers, and 4 lesions were advanced cancers. Twenty-two lesions of superficial cancer were differentiated type, and the remaining seven lesions were undifferentiated type. Treatment for superficial cancer had previously been performed with partial gastric tube resection (10 lesions), and the number of cases undergoing endoscopic submucosal dissection (ESD) had increased recently (19 lesions). Most cases with superficial cancer survived without relapse. Four lesions of advanced cancer were found after a relatively long interval following TEC surgery. Most lesions of advanced cancer were scirrhous, undifferentiated type, and they died due to GTC. CONCLUSION: GTCs may occur late in the postoperative course following TEC surgery. If they are discovered at an early stage, these lesions can be cured with ESD. Long-term periodic endoscopic examinations after TEC surgery are important.

Cancer-Associated Fibroblasts Affect Intratumoral CD8+ and FoxP3+ T Cells Via IL6 in the Tumor Microenvironment.

Purpose: Cancer-associated fibroblasts (CAFs) in the tumor microenvironment (TME) play a central role in tumor progression. We investigated whether CAFs can regulate tumor-infiltrating lymphocytes (TILs) and their role in tumor immunosuppression.Experimental Design: A total of 140 cases of esophageal cancer were analyzed for CAFs and CD8+ or forkhead box protein 3 (FoxP3+) TILs by IHC. We analyzed cytokines using murine or human fibroblasts and cancer cells. Murine-derived fibroblasts and cancer cells were also inoculated into BALB/c or BALB/c-nu/nu mice and the tumors treated with recombinant IL6 or anti-IL6 antibody.Results: CD8+ TILs and CAFs were negatively correlated in intratumoral tissues (P < 0.001), whereas FoxP3+ TILs were positively correlated (P < 0.001) in esophageal cancers. Cocultured Colon26 cancer cells and fibroblasts resulted in accelerated tumor growth in BALB/c mice, along with decreased CD8+ and increased FoxP3+ TILs, compared with cancer cells alone. In vitro, IL6 was highly secreted in both murine and human cancer cell/fibroblast cocultures. IL6 significantly increased Colon26 tumor growth in immune-competent BALB/c (P < 0.001) with fewer CD8+ TILs than untreated tumors (P < 0.001), whereas no difference in BALB/c-nu/nu mice. In contrast, FoxP3+ TILs increased in IL6-treated tumors (P < 0.001). IL6 antibody blockade of tumors cocultured with fibroblasts resulted not only in regression of tumor growth but also in the accumulation of CD8+ TILs in intratumoral tissues.Conclusions: CAFs regulate immunosuppressive TIL populations in the TME via IL6. IL6 blockade, or targeting CAFs, may improve preexisting tumor immunity and enhance the efficacy of conventional immunotherapies. Clin Cancer Res; 24(19); 4820-33. ©2018 AACR.

Visualized Evaluation of Blood Flow to the Gastric Conduit and Complications in Esophageal Reconstruction.

BACKGROUND: Evaluation of the blood supply to gastric conduits is critically important to avoid complications after esophagectomy. We began visual evaluation of blood flow using indocyanine green (ICG) fluorescent imaging in July 2015, to reduce reconstructive complications. In this study, we aimed to statistically verify the efficacy of blood flow evaluation using our simplified ICG method. STUDY DESIGN: A total of 285 consecutive patients who underwent esophagectomy and gastric conduit reconstruction were reviewed and divided into 2 groups: before and after introduction of ICG evaluation. The entire cohort and 68 patient pairs after propensity score matching (PS-M) were evaluated for clinical outcomes and the effect of visualized evaluation on reducing the risk of complication. RESULTS: The leakage rate in the ICG group was significantly lower than in the non-ICG group for each severity grade, both in the entire cohort (285 subjects) and after PS-M; the rates of other major complications, including recurrent laryngeal nerve palsy and pneumonia, were not different. The duration of postoperative ICU stay was approximately 1 day shorter in the ICG group than in the non-ICG group in the entire cohort, and approximately 2 days shorter after PS-M. Visualized evaluation of blood flow with ICG methods significantly reduced the rate of anastomotic complications of all Clavien-Dindo (CD) grades. Odds ratios for ICG evaluation decreased with CD grade (0.3419 for CD ≥ 1; 0.241 for CD ≥ 2; and 0.2153 for CD ≥ 3). CONCLUSIONS: Objective evaluation of blood supply to the reconstructed conduit using ICG fluorescent imaging reduces the risk and degree of anastomotic complication.

Iron depletion is a novel therapeutic strategy to target cancer stem cells.

Adequate iron levels are essential for human health. However, iron overload can act as catalyst for the formation of free radicals, which may cause cancer. Cancer stem cells (CSCs), which maintain the hallmark stem cell characteristics of self-renewal and differentiation capacity, have been proposed as a driving force of tumorigenesis and metastases. In the present study, we investigated the role of iron in the proliferation and stemness of CSCs, using the miPS-LLCcm cell model. Although the anti-cancer agents fluorouracil and cisplatin suppressed the proliferation of miPS-LLCcm cells, these drugs did not alter the expression of stemness markers, including Nanog, SOX2, c-Myc, Oct3/4 and Klf4. In contrast, iron depletion by the iron chelators deferasirox and deferoxamine suppressed the proliferation of miPS-LLCcm cells and the expression of stemness markers. In an allograft model, deferasirox inhibited the growth of miPS-LLCcm implants, which was associated with decreased expression of Nanog and Sox2. Altogether, iron appears to be crucial for the proliferation and maintenance of stemness of CSCs, and iron depletion may be a novel therapeutic strategy to target CSCs.

[Successful Multimodality Treatment Including Three-Stage Operation for Esophageal Cancer with Esophagorespiratory Fistula - A Case Report].

The esophagorespiratory fistula(ERF)is a fatal complication ofesophageal cancer, because ofadvanced oncological status and poor conditions due to pneumonia and/or malnutrition.We report here a case of patient who was successfully treated for esophageal cancer with ERF with multimodality therapy including three-stage operation. A 65-year-old woman ofesophageal cancer received preoperative chemotherapy, and developed EFR before operation. Prolonged conservative therapies for ERF let her general condition get worse. Therefore, the patient underwent esophagostomy and gastrostomy to recover her condition. She received chemo-radiotherapy followed by esophagectomy. And she was performed the reconstruction next month. She is still alive without recurrence at 20 months after resection. In previous reports, a total of 6 cases have been performed esophagectomy for esophageal cancer with ERF in Japan. Only one case was reported that had survived longer than 12 months. This multimodality therapy can be one ofthe best strategies for the patients ofesophageal cancer with ERF, even ifthey have poor condition.

[Radical Thoracoscopic Esophagectomy for Elderly Patients with Advanced Esophageal Cancer].

We report a case of an elderly patient with advanced esophageal cancer who underwent multidisciplinary treatment. An 86-year-old male consulted our hospital with complaints of pharynx discomfort and difficulty in swallowing. He was preoperatively diagnosed with esophageal cancer, T3N2M0, Stage III . We performed 2 courses of cisplatin plus 5-FU therapy as neoadjuvant chemotherapy. The primary tumor and metastatic lymph nodes reduced in size, and thoracoscopic esophagectomy in the prone position was performed. Pathological findings were esophageal cancer, pT3-Ad, INF b, ly2, v1, IM0, pPM0, pDM0, pRM1, pN3, pStage III . As the radical margin was positive, chemoradiotherapy was performed. We continued postoperative chemotherapy for approximately 1 year, and the patient has survived without relapse for 4 years from esophagectomy. Even in patients over 80 years old, long-term prognosis can be expected by performing radical surgery and chemoradiotherapy.

Iron depletion enhances the effect of sorafenib in hepatocarcinoma.

ABSTACT Human hepatocellular carcinoma (HCC) is known to have a poor prognosis. Sorafenib, a molecular targeted drug, is most commonly used for HCC treatment. However, its effect on HCC is limited in clinical use and therefore new strategies regarding sorafenib treatment are required. Iron overload is known to be associated with progression of chronic hepatitis and increased risk of HCC. We previously reported that iron depletion inhibited cancer cell proliferation and conversely induced angiogenesis. Indeed iron depletion therapy including iron chelator needs to be combined with anti-angiogenic drug for its anti-cancer effect. Since sorafenib has an anti-angiogenic effect by its inhibitory targeting VEGFR, we hypothesized that sorafenib could complement the anti-cancer effect of iron depletion. We retrospectively analyzed the relationship between the efficacy of sorafenib and serum iron-related markers in clinical HCC patients. In clinical cases, overall survival was prolonged in total iron binding capacity (TIBC) high- and ferritin low-patients. This result suggested that the low iron-pooled patients, who could have a potential of more angiogenic properties in/around HCC tumors, could be adequate for sorafenib treatment. We determined the effect of sorafenib (Nexavar®) and/or deferasirox (EXJADE®) on cancer cell viability, and on cell signaling of human hepatocarcinoma HepG2 and HLE cells. Both iron depletion by deferasirox and sorafenib revealed insufficient cytotoxic effect by each monotherapy, however, on the basis of increased angiogenesis by iron depletion, the addition of deferasirox enhanced anti-proliferative effect of sorafenib. Deferasirox was confirmed to increase vascular endothelial growth factor (VEGF) secretion into cellular supernatants by ELISA analysis. In in vivo study sorafenib combined with deferasirox also enhanced sorafenib-induced apoptosis. These results suggested that sorafenib combined with deferasirox could be a novel combination chemotherapy for HCC.

[Therapeutic Potential of Targeting Cancer-Associated Fibroblasts in Esophageal Cancer].

Advances in molecular and cellular biochemistry, such as the development of targeted cancer therapy, have dramatically improved the prognosis of cancer patients. Emerging data have suggested that bevacizumab treatment may act by controlling the cancer microenvironment. Many reports have examined the interaction of cancer cells with the tumor microenvironment, and cancer-associated fibroblasts (CAFs) are thought to play a central role in this process. We speculated that the cancer microenvironment and in particular, CAFs, strongly influence the development of esophageal cancer. We have analyzed the signaling pathways of molecular targets. However, inhibition of a single signaling pathway is insufficient to treat cancer effectively. Photoimmunotherapy is a molecular-targeted specific cancer therapy using near-infrared radiation, which was introduced by Mitsunaga et al. in 2011. We are using its specific method of killing cells to target CAFs. We will report the results of its effect on cancer cells in the future.

Hepatectomy in a hepatocellular carcinoma case with Dubin-Johnson syndrome and indocyanine green excretory defect.

A 77-year-old male patient with history of jaundice was referred to our hospital for treatment of hepatocellular carcinoma (HCC). He was found to have Dubin-Johnson syndrome (DJS), a clinical feature of constitutional jaundice with conjugated hyperbilirubinemia, and indocyanine green (ICG) excretory defect, both of which are rare conditions. Total bilirubin was 5.1 mg/dl and ICG retention at 15 min (ICGR15) (77.1 %). Converted ICGR15 from GSA scintigraphy was 15.9 %. Resection of the medial segment and ventral region of the anterior segment of the liver as well as cholecystectomy were performed. The background of the liver tissue was blackish yellow and consistent with DJS and chronic hepatitis. Although total bilirubin level increased to 8.2 mg/dl on the 2nd postoperative day, the patient ultimately recovered and he was discharged on the 14th day. His 1- and 2-year medical checkups indicated recurrence of HCC. He underwent transarterial chemoembolization and is presently doing well 39 months after surgery. We report here on evaluation and treatment of patients with such disorders.

[A case of advanced colon cancer with multiple liver metastases treated by two-stage laparoscopic surgery].

We report a case of advanced colon cancer with multiple liver metastases treated by two-stage laparoscopic surgery. An 82-year-old woman, whose main complaint was constipation, was diagnosed with stage IV sigmoid colon cancer. With the aim of decompressing the colon, a transanal decompression tube was inserted. She underwent laparoscopic-assisted sigmoidectomy and D3 lymph node dissection, and an ileostomy was created. Systemic chemotherapy was administered immediately after the operation. After 4 courses of chemotherapy, she underwent the second operation, i.e., laparoscopic- assisted partial hepatectomy and radiofrequency ablation of liver metastases. Cases of obstructive colon cancer are more advanced than cases of non-obstructive colon cancer. Systemic treatments are required after the resection of primary tumors. We aim to improve the prognosis of patients with obstructive colon cancer by the use of laparoscopic surgery.

[A case of lynch syndrome treated laparoscopically for multiple colon cancers].

Lynch syndrome is an inherited syndrome associated with the development of colorectal, endometrial, stomach, and other cancers; it is caused by defects in the mismatch repair genes. Such patients are at risk of developing multiple abdominal cancers after colectomy, and the presence of adhesions may render future abdominal surgeries difficult. We recommend that patients with Lynch syndrome should be considered good candidates for laparoscopic surgery. A 43-year-old Japanese man was admitted following a positive fecal occult blood test result. The patient was diagnosed with multiple colon cancers in the right colon. He had undergone endoscopic mucosal resection for a colon polyp when he was 24 years of age. Two people among his father's second-degree relatives had colorectal cancer, and he fulfilled the revised Bethesda guidelines. He underwent laparoscopic-assisted right hemicolectomy and D3 lymph node dissection. Microsatellite instability testing indicated the presence of MSI-H, and genetic testing demonstrated a pathogenic mutation of MLH-1.