Fibroblast activation protein targeted near infrared photoimmunotherapy (NIR PIT) overcomes therapeutic resistance in human esophageal cancer.

Cancer-associated fibroblasts (CAFs) have an important role in the tumor microenvironment. CAFs have the multifunctionality which strongly support cancer progression and the acquisition of therapeutic resistance by cancer cells. Near-infrared photoimmunotherapy (NIR-PIT) is a novel cancer treatment that uses a highly selective monoclonal antibody (mAb)-photosensitizer conjugate. We developed fibroblast activation protein (FAP)-targeted NIR-PIT, in which IR700 was conjugated to a FAP-specific antibody to target CAFs (CAFs-targeted NIR-PIT: CAFs-PIT). Thus, we hypothesized that the control of CAFs could overcome the resistance to conventional chemotherapy in esophageal cancer (EC). In this study, we evaluated whether EC cell acquisition of stronger malignant characteristics and refractoriness to chemoradiotherapy are mediated by CAFs. Next, we assessed whether the resistance could be rescued by eliminating CAF stimulation by CAFs-PIT in vitro and in vivo. Cancer cells acquired chemoradiotherapy resistance via CAF stimulation in vitro and 5-fluorouracil (FU) resistance in CAF-coinoculated tumor models in vivo. CAF stimulation promoted the migration/invasion of cancer cells and a stem-like phenotype in vitro, which were rescued by elimination of CAF stimulation. CAFs-PIT had a highly selective effect on CAFs in vitro. Finally, CAF elimination by CAFs-PIT in vivo demonstrated that the combination of 5-FU and NIR-PIT succeeded in producing 70.9% tumor reduction, while 5-FU alone achieved only 13.3% reduction, suggesting the recovery of 5-FU sensitivity in CAF-rich tumors. In conclusion, CAFs-PIT could overcome therapeutic resistance via CAF elimination. The combined use of novel targeted CAFs-PIT with conventional anticancer treatments can be expected to provide a more effective and sensible treatment strategy.

Photoimmunotherapy for cancer-associated fibroblasts targeting fibroblast activation protein in human esophageal squamous cell carcinoma.

Cancer-associated fibroblasts (CAFs) are strongly implicated in tumor progression, including in the processes of tumorigenesis, invasion, and metastasis. The targeting of CAFs using various therapeutic approaches is a novel treatment strategy; however, the efficacy of such therapies remains limited. Recently, near-infrared photoimmunotherapy (NIR-PIT), which is a novel targeted therapy employing a cell-specific mAb conjugated to a photosensitizer, has been introduced as a new type of phototherapy. In this study, we have developed a novel NIR-PIT technique to target CAFs, by focusing on fibroblast activation protein (FAP), and we evaluate the treatment efficacy in vitro and in vivo. Esophageal carcinoma cells exhibited enhanced activation of fibroblasts, with FAP over-expressed in the cytoplasm and on the cell surface. FAP-IR700-mediated PIT showed induced rapid cell death specifically for those cells in vitro and in vivo, without adverse effects. This novel therapy for CAFs, designed as local control phototherapy, was safe and showed a promising inhibitory effect on FAP+ CAFs. PIT targeting CAFs via the specific marker FAP may be a therapeutic option for CAFs in the tumor microenvironment in the future.

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.

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.

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.

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.

Ultrasound-guided block of selective branches of the brachial plexus for vascular access surgery in the forearm: a preliminary report.

PURPOSE: The operative field for vascular access (VA) surgery in the forearm is on the volar surface, and motor nerve block is not necessary for regional anesthesia. Therefore, selective block of branches of the brachial plexus may be a more efficient anesthesia technique. METHODS: Individual nerve blocks in the axillary brachial plexus and selective blocks of the musculocutaneous and medial antebrachial cutaneous nerves in the upper arm were performed using low doses and concentrations of a local anesthetic mixture of lidocaine and ropivacaine under ultrasound (US) guidance in patients undergoing VA surgery in the forearm. The targeted nerves were identified by continuous US tracing along the upper arm to the axilla in a short-axis view. We performed three VA surgeries in the forearm using an axillary brachial plexus block and four using a selective two-nerve bock in the upper arm. We recorded any additional anesthetic requirement and evaluated intraoperative pain using the Wong-Baker Faces Pain Rating Scale (WBFRS; 0 = no pain; 10 = worst pain). RESULTS: All of the target nerve branches were clearly identified by US tracing. All patients had satisfactory intraoperative pain control (0 or 2 score on WBFRS). Four patients required small additional doses of local anesthetic. CONCLUSIONS: US-guided block of individual branches of the brachial plexus at the axilla achieved effective anesthesia using small amounts of local anesthetic. An advanced selective nerve block in the upper arm allows minimum necessary anesthesia and provides safe and efficient analgesia for VA surgery in the forearm.

[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.

Assistant-based standardization of prone position thoracoscopic esophagectomy.

Thoracoscopic esophagectomy in the prone position (TEPP) might enable solo-surgery in cases requiring resection of the esophagus and the surrounding lymph nodes due to the associated advantages of good exposure of the surgical field and ergonomic considerations for the surgeon. However, no one approach can be for all patients requiring extensive lymphadenectomy. We recently developed an assistant-based procedure to standardize exposure of the surgical field. Patients were divided into 1 of 2 groups:a pre-standardization group (n=37) and a post-standardization group (n=28). The thoracoscopic operative time was significantly shorter (p=0.0037) in the post-standardization group (n=28; 267 ± 31 min) than in the pre-standardization group (n=37;301 ± 53 min). Further, learning curve analysis using the moving average method showed stabilization of the thoracoscopic operative time after the standardization. No significant differences were found in the number of mediastinal lymph nodes dissected or intraoperative blood loss between the 2 groups. There were also no significant differences in the complication rate. Assistant-based surgery and standardization of the procedure resulted in a well-exposed and safe surgical field. TEPP decreased the operative time, even in patients requiring extensive lymphadenectomy.

Successfully treated pneumatosis cystoides intestinalis with pneumoperitoneum onset in a patient administered α-glucosidase inhibitor.

An 80-year-old woman, who had been administered α-glucosidase inhibitor for diabetes, was brought to the hospital with the sensation of abdominal fullness and pain. Abdominal computed tomography indicated pneumatosis cystoides intestinalis (PCI) in the small intestinal wall, with free air within the abdomen. A blood examination showed no increases in white blood cells or C-reactive protein level. The patient's condition improved with conservative therapy. PCI with pneumoperitoneum induced by α-glucosidase inhibitor is rare, with only 27 cases (excluding the present case) reported in Japan to date. In PCI with pneumoperitoneum, differentiation from gastrointestinal perforation is important and following the clinical symptoms over time is vital.

[Current status of neoadjuvant chemotherapy for advanced esophageal cancer].

Since reported in the JCOG9907 trial, neoadjuvant chemotherapy prior to surgery has become the standard treatment for advanced (Stage II/III) esophageal cancers. However, more powerful neoadjuvant chemotherapy is required for the treatment of locally advanced cases or cases involving multiple lymph node metastases. At our institute, DCF therapy (docetaxel, cisplatin, and 5-fluorouracil) is administered selectively for the treatment of patients with far-advanced esophageal cancer. We treated 53 thoracic esophageal cancer patients who underwent surgery following neoadjuvant chemotherapy between January 2010 and December 2012. FP therapy (cisplatin and 5-fluorouracil) was administered to 43 patients, and DCF therapy to 7 patients who had far-advanced esophageal cancer. All patients treated with DCF therapy experienced grade 3 and 4 adverse events. With the exception of 1 patient, all patients who received DCF therapy could undergo curative surgery. DCF therapy could become an effective preoperative chemotherapy.