Search

This study investigates methylation patterns in circulating cell-free DNA (ccfDNA) for their potential role in colorectal cancer (CRC) detection and the monitoring of treatment response. Through methylation microarrays and quantitative PCR assays, we analyzed 440 samples from The Cancer Genome Atlas (TCGA) and an additional 949 CRC samples. We detected partial or extensive methylation in over 85% of cases within three biomarkers: EFEMP1, SFRP2, and UNC5C. A methylation score for at least one of the six candidate regions within these genes' promoters was present in over 95% of CRC cases, suggesting a viable detection method. In evaluating ccfDNA from 97 CRC patients and 62 control subjects, a difference in methylation and recovery signatures was observed. The combined score, integrating both methylation and recovery metrics, showed high diagnostic accuracy, evidenced by an area under the ROC curve of 0.90 (95% CI = 0.86 to 0.94). While correlating with tumor burden, this score gave early insight into disease progression in a small patient cohort. Our results suggest that DNA methylation in ccfDNA could serve as a sensitive biomarker for CRC, offering a less invasive and potentially more cost-effective approach to augment existing cancer detection and monitoring modalities, possibly supporting comprehensive genetic mutation profiling. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this clinical study was to be the first to explore whether ART-123, a recombinant human soluble thrombomodulin, prevents oxaliplatin-induced peripheral neuropathy (OIPN). Methods: This randomized, phase IIa trial enrolled stage II/III colon cancer patients who received adjuvant mFOLFOX6 chemotherapy. Participants were randomly allocated to 3 arms in a double-blind manner: placebo (placebo: days 1–3); 1-day ART (ART-123: day 1, placebo: days 2–3); and 3-day ART (ART-123: days 1–3). ART-123 (380 U/kg/day) or placebo was infused intravenously before each 2-week cycle of mFOLFOX6. OIPN was assessed with the Functional Assessment of Cancer Therapy/Gynecological Oncology Group-Neurotoxicity-12 (FACT/GOG-Ntx-12) score by participants and the NCI Common Terminology Criteria for Adverse Events (NCI-CTCAE) by investigators. Results: Seventy-nine participants (placebo n = 28, 1-day ART n = 27, 3-day ART n = 24) received study drugs. The least-squares mean FACT/GOG-Ntx-12 scores at cycle 12 from the mixed effect model for repeated measures were 28.9 with placebo, 36.3 with 1-day ART (vs. placebo: 7.3 [95% CI 1.9 to12.8, p = 0.009]), and 32.3 with 3-day ART (vs. placebo: 3.4 [95% CI −.1 to 9.0, p = 0.222]). The cumulative incidence of NCI-CTCAE grade ≥ 2 sensory neuropathy at cycle 12 was 64.3% with placebo, 40.7% with 1-day ART (vs. placebo: −23.5 [95% CI −48.4 to 4.0], p = 0.108), and 45.8% with 3-day ART (vs. placebo: −18.5 [95% CI −44.2 to 9.4], p = 0.264). Common adverse events were consistent with those reported with mFOLFOX6; no severe bleeding adverse events occurred. Conclusion: ART-123 showed a potential preventive effect against OIPN with good tolerability. A larger study with 1-day ART is warranted. NCT02792842, registration date: June 8, 2016 [ABSTRACT FROM AUTHOR]

Background: Small bowel adenocarcinoma (SBA) is a rare malignancy that accounts for 1-2% of gastrointestinal tumours. We investigated the clinical characteristics, outcomes, and prognostic factors of primary SBA.Methods: We retrospectively analysed the characteristics and clinical courses of 205 SBA patients from 11 institutions in Japan between June 2002 and August 2013.Results: The primary tumour was in the duodenum and jejunum/ileum in 149 (72.7%) and 56 (27.3%) patients, respectively. Sixty-four patients (43.0%) with duodenal adenocarcinoma were asymptomatic and most cases were detected by oesophagogastroduodenoscopy (EGD), which was not specifically performed for the detection or surveillance of duodenal tumours. In contrast, 47 patients (83.9%) with jejunoileal carcinoma were symptomatic. The 3-year survival rate for stage 0/I, II, III, and IV cancers was 93.4%, 73.1%, 50.9%, and 15.1%, respectively. Multivariate analysis revealed performance status 3-4, high carcinoembryonic antigen, high lactate dehydrogenase (LDH), low albumin, symptomatic at diagnosis, and stage III/IV disease were independent factors for overall survival (OS). Ten patients (18.5%) with stage IV disease were treated with a combination of resection of primary tumour, local treatment of metastasis, and chemotherapy; this group had a median OS of 36.9 months.Conclusions: Although most SBA patients were diagnosed with symptomatic, advanced stage disease, some patients with duodenal carcinoma were detected in early stage by EGD. High LDH and symptomatic at diagnosis were identified as novel independent prognostic factors for OS. The prognosis of advanced SBA was poor, but combined modality therapy with local treatment of metastasis might prolong patient survival. [ABSTRACT FROM AUTHOR]

Background: Esophageal carcinomas are highly malignant tumors with a high frequency of lymph node and distant organ metastasis. Treatment for recurrent tumors is generally decided on an individual basis. Although multidisciplinary treatments involving chemotherapy, surgical resection, and radiation are performed, the prognosis remains poor. Here, we report a case of prolonged recurrence-free survival (38 months) after esophageal carcinoma surgery and subsequent laparoscopic adrenalectomy for right adrenal metastasis. Case presentation: An 83-year-old man was diagnosed with type 3 esophageal squamous cell carcinoma (T3N1M0, cStage IIIA, UICC-7), spreading from the lower thoracic esophagus to the abdominal esophagus. He underwent thoracoscopic esophagectomy with a two-field lymph node dissection followed by substernal gastric tube reconstruction. The final diagnosis was moderately differentiated squamous cell carcinoma (T3N2M0, fStage IIIB). Adjuvant chemotherapy was not administered because of the advanced age and postoperative condition of the patient. Computed tomography (CT) at 14 months postoperatively showed a mass with a 2-cm diameter at the right adrenal gland. Positron emission tomography (PET)/CT revealed a high fluorodeoxyglucose (FDG) uptake in the mass. It was suspected that the mass was a metastatic lesion secondary to the primary esophageal carcinoma. No metastases to lymph nodes or other distant organs were identified. The patient underwent laparoscopic right adrenalectomy. The histopathological examination revealed moderately differentiated squamous cell carcinoma, suggesting metastasis from the primary esophageal carcinoma. He has survived without recurrence for 38 months since laparoscopic adrenalectomy to remove the right adrenal metastastic mass after the esophageal carcinoma surgery. Conclusions: We describe a very elderly male who survived laparoadrenalectomy for right adrenal metastasis following esophageal cancer surgery without recurrence for 38 months postoperatively. Therefore, surgical resection might be an option for solitary adrenal recurrence. [ABSTRACT FROM AUTHOR]

Stomach cancer carcinomatosis peritonitis (SCCP) is a recalcitrant disease. The goal of the present study was to establish an in vitro-in vivo-like imageable model of SCCP to develop cell-cycle-based therapeutics of SCCP. We established 3-D Gelfoam® histoculture and tumor-sphere models of SCCP. FUCCI-expressing MKN-45 stomach cancer cells were transferred to express the fluorescence ubiquinized cell-cycle indicator (FUCCI). FUCCI-expressing MKN-45 cells formed spheres on agarose or on Gelfoam® grew into tumor-like structures with G0/G1 cancer cells in the center and S/G2 cancer cells located in the surface as indicated by FUCCI imaging when the cells fluoresced red or green, respectively. We treated FUCCI-expressing cancer cells forming SCCP tumors in Gelfoam® histoculture with OBP-301, cisplatinum (CDDP), or paclitaxel. CDDP or paclitaxel killed only cycling cancer cells and were ineffective against G1/G2 MKN-45 cells in tumors growing on Gelfoam®. In contrast, the telomerase-dependent adenovirus OBP-301 decoyed the MKN-45 cells in tumors on Gelfoam® to cycle from G0/G1 phase to S/G2 phase and reduced their viability. CDDP- or paclitaxel-treated MKN-45 tumors remained quiescent and did not change in size. In contrast, OB-301 reduced the size of the MKN-45 tumors on Gelfoam®. We examined the cell cycle-related proteins using Western blotting. CDDP increased the expression of p53 and p21 indicating cell cycle arrest. In contrast, OBP-301 decreased the expression of p53 and p21 Furthermore, OBP-301 increased the expression of E2F and pAkt as further indication of cell cycle decoy. This 3-D Gelfoam® histoculture and FUCCI imaging are powerful tools to discover effective therapy of SCCP such as OBP-301. [ABSTRACT FROM AUTHOR]

In 2006, the Adjuvant Chemotherapy Trial of S-1 for Gastric Cancer (ACTS-GC) demonstrated that S-1 is an effective adjuvant therapy for gastric cancer. Following that study, S-1 has been used as the standard adjuvant therapy for gastric cancer in Japan. However, the 1-year completion rate was only 65.8% in the ACTS-GC study and feasibility remains a critical issue. We conducted a study to evaluate the feasibility of 2 weekly administration regimens of S-1 as adjuvant chemotherapy in gastric cancer. The criteria for eligibility included histologically proven stage II (excluding T1), IIIA or IIIB gastric cancer with D2 lymph-node dissection. The patients were randomly assigned to either arm A (S-1 administration for 4 weeks followed by 2 weeks of rest) or arm B (S-1 administration for 2 weeks followed by 1 week of rest). In each arm, treatment was continued for 12 months unless recurrence or severe adverse events were observed. The primary endpoint was feasibility (protocol treatment completion rate). The secondary endpoints were safety, relapse-free survival and overall survival. A total of 47 patients were assigned to arms A or B between May, 2008 and February, 2010. During the first interim analysis, the protocol treatment completion rates in arms A and B were 83 and 100%, respectively, at 6 months and 49 and 89%, respectively, at 12 months (P=0.0046). Therefore, S-1 administration for 2 weeks followed by 1 week rest was more feasible as adjuvant chemotherapy in gastric cancer. Grade 3 adverse events in arm A included fatigue (8.0%), anorexia (8.0%), nausea (4.0%), vomiting (4.0%) and hand-foot syndrome (4.0%), whereas none were observed in arm B. There were no reported grade 4 adverse events in either arm. In conclusion, the 2-week S-1 administration followed by 1-week rest regimen appears to be a more feasible oral administration regimen for S-1 as adjuvant chemotherapy in gastric cancer. [ABSTRACT FROM AUTHOR]

Antigen-specific cancer immunotherapy is a promising strategy for improving cancer treatment. Recently, many tumor-associated antigens and their epitopes recognized by cytotoxic T lymphocytes (CTLs) have been identified. However, the density of endogenously presented antigen-derived peptides on tumor cells is generally sparse, resulting in the inability of antigen-specific CTLs to work effectively. We hypothesize that increasing the density of an antigen-derived peptide would enhance antigen-specific cancer immunotherapy. Here, we demonstrated that intratumoral peptide injection leads to additional peptide loading onto major histocompatibility complex class I molecules of tumor cells, enhancing tumor cell recognition by antigen-specific CTLs. In in vitro studies, human leukocyte antigen (HLA)-A*02:01-restricted glypican-3 (FVGEFFTDV) and cytomegalovirus (NLVPMVATV) peptide-specific CTLs showed strong activity against all peptide-pulsed cell lines, regardless of whether the tumor cells expressed the antigen. In in vivo studies using immunodeficient mice, glypican-3 and cytomegalovirus peptides injected into a solid mass were loaded onto HLA class I molecules of tumor cells. In a peptide vaccine model and an adoptive cell transfer model using C57BL/6 mice, intratumoral injection of ovalbumin peptide (SIINFEKL) was effective for tumor growth inhibition and survival against ovalbumin-negative tumors without adverse reactions. Moreover, we demonstrated an antigen-spreading effect that occurred after intratumoral peptide injection. Intratumoral peptide injection enhances tumor cell antigenicity and may be a useful option for improvement in antigen-specific cancer immunotherapy against solid tumors. [ABSTRACT FROM AUTHOR]

Purpose: Peritoneal dissemination is the most frequent and life-threatening mode of metastasis and recurrence in patients with gastric cancer. A multicenter phase II study was designed to evaluate the efficacy and tolerability of S-1 and docetaxel combination chemotherapy regimen for the treatment of advanced or recurrent gastric cancer patients with peritoneal dissemination. Methods: Nineteen patients with histologically confirmed unresectable or recurrent gastric cancer with peritoneal dissemination were enrolled. Oral S-1 at 80 mg/m/day was administered twice daily for 2 weeks, followed by 1 drug-free week. Docetaxel infusion at 40 mg/m was performed on day 1, simultaneous with S-1 administration. The primary endpoints were overall survival (OS) and time to progression (TTP). The secondary endpoints were the response rates and safety status. Results: Patients received a median of 4 cycles of the S-1 and docetaxel regimen (range 1-43). The disease control rate was 73.7 % (14/19). Median overall survival was 459 days (15.3 months), while median time to progression was 212 days (7.1 months). Neutropenia was the most common type of toxicity ( n = 7, 36.8 %). Conclusions: Combination chemotherapy with S-1 and docetaxel is a tolerable and effective treatment for advanced or recurrent gastric cancer patients with peritoneal dissemination. [ABSTRACT FROM AUTHOR]

Apoptosis is a morphologically distinct form of programmed cell death that plays a major role in cancer treatments. This cellular suicide program is known to be regulated by many different signals from both intracellular and extracellular stimuli. Here we report that p53 suppressed expression of the cellular FLICE-inhibitory protein (FLIP) that potentially blocks apoptotic signaling in human colon cancer cell lines expressing mutated and wild-type p53. In contrast, the expression of the death receptor KILLER/DR5 (TRAIL-R2) had no effect on FLIP expression, although exogenous p53 is known to induce KILLER/DR5 expression. In line with these observations, FLIP-negative cancer cells were sensitive to both p53- and KILLER/DR5-mediated apoptosis, whereas cells containing high levels of FLIP underwent apoptotic cell death when triggered by ectopic p53 expression but not by KILLER/DR5 expression. Treating the cells with a specific inhibitor of the proteasome inhibited the decrease of FLIP by p53, suggesting that p53 enhances the degradation of FLIP via a ubiquitin-proteasome pathway. Thus, the data indicate that p53-mediated downregulation of FLIP may explain the potent sensitization of human cancer cells to the apoptotic suicide program induced by wild-type p53 gene transfer. Oncogene (2001) 20, 5225–5231. [ABSTRACT FROM AUTHOR]

Background The neoadjuvant chemotherapy using CDDP and 5-FU(CF) is the standard treatment for advanced esophageal cancer, defined as clinical stage II/III in Japan. However, more powerful chemotherapy has been required for the treatment of cases of cStageIII cases. In 2011, the combination treatment of CF and Docetaxel (DCF) was introduced for the treatment of those cases in our institute. DCF therapy increased chemotherapy remarkable cases. But, adverse events occur at high rates, including high myelosuppression. Therefore, it is necessary to ensure support by early intervention of supportive therapy so as not to exacerbate adverse events. We report about treatment outcome in preoperative DCF therapy cases. Methods We treated 128 esophageal cancer patients who underwent surgery following preoperative DCF therapy between 2011 and July 2017, and preoperative DCF was administered to 128 patients 2 course completely. The neoadjuvant chemotherapy regimen using DCF is Docetaxel:70mg/m2 (day1) + CDDP:70mg/m2 (day1) + 5-FU:700mg/m2 (day1–5). Results In the preoperative DCF group, overall response rate (over PR) was 51.5%. There were 37 cases in 128 cases of pathological tissue effect judgment for Grade 2 and 3. 14 cases of them (14cases/37cases:37.8%) had lymph node metastasis. Therefore it is necessary to control lymph node metastasis by surgery even in a remarkable group. Almost all patients experienced grade 4 adverse events, particularly neutropenia is a high frequency. From the start of chemotherapy, pretreatment of intraoral infection lesion and prevention and treatment of oral mucositis are performed. Considering the degree of myelosuppression during initial chemotherapy, in the second course, we actively administer G-CSF preparation. Conclusion A good prognosis can be expected if preoperative DCF therapy is effective. It is necessary to perform intensive and safe preoperative chemotherapy with appropriate supportive therapy intervention. Disclosure All authors have declared no conflicts of interest. [ABSTRACT FROM AUTHOR]

Oncolytic virotherapy is one of the most promising, emerging cancer therapeutics. We generated three types of telomerase-specific replication-competent oncolytic adenovirus: OBP-301; a green fluorescent protein (GFP)-expressing adenovirus, OBP-401; and Killer-Red-armed OBP-301. These oncolytic adenoviruses are driven by the human telomerase reverse transcriptase (hTERT) promoter; therefore, they conditionally replicate preferentially in cancer cells. Fluorescence imaging enables visualization of invasion and metastasis in vivo at the subcellular level; including molecular dynamics of cancer cells, resulting in greater precision therapy. In the present review, we focused on fluorescence imaging applications to develop precision targeting for oncolytic virotherapy. Cell-cycle imaging with the fluorescence ubiquitination cell cycle indicator (FUCCI) demonstrated that combination therapy of an oncolytic adenovirus and a cytotoxic agent could precisely target quiescent, chemoresistant cancer stem cells (CSCs) based on decoying the cancer cells to cycle to S-phase by viral treatment, thereby rendering them chemosensitive. Non-invasive fluorescence imaging demonstrated that complete tumor resection with a precise margin, preservation of function, and prevention of distant metastasis, was achieved with fluorescence-guided surgery (FGS) with a GFP-reporter adenovirus. A combination of fluorescence imaging and laser ablation using a KillerRed-protein reporter adenovirus resulted in effective photodynamic cancer therapy (PDT). Thus, imaging technology and the designer oncolytic adenoviruses may have clinical potential for precise cancer targeting by indicating the optimal time for administering therapeutic agents; accurate surgical guidance for complete resection of tumors; and precise targeted cancer-specific photosensitization. [ABSTRACT FROM AUTHOR]

Multidisciplinary therapy centered on radical surgery for resectable pancreatic cancer is expected to prolong prognosis, but relies on CA19-9 biomarker levels to determine treatment strategy. Boron neutron capture therapy (BNCT) is a chemoradiotherapy using tumor hyperaccumulator boron drugs and neutron irradiation. The purpose of this study is to investigate novel boron drug agents for BNCT for pancreatic cancer. Bioinformatics was used to evaluate the uptake of current boron amino acid (BPA) drugs for BNCT into pancreatic cancer. The expression of the amino acid transporter LAT1, a BPA uptake transporter, was low in pancreatic cancer and even lower in high CA19-9 pancreatic cancer. In contrast, the glucose transporter was high in high CA19-9 pancreatic cancers and inversely correlated with LAT1 expression. Considering the low EPR effect in pancreatic cancer, we synthesized a small molecule Glucose-BSH, which is boron BSH bound to glucose, and confirmed its specific uptake in pancreatic cancer. uptake of Glucose-BSH was confirmed in an environment compatible with the tumor microenvironment. The therapeutic efficacy and safety of Glucose-BSH by therapeutic neutron irradiation were confirmed with BNCT. We report Glucose-BSH boron drug discovery study of a Precision Medicine BNCT with application to high CA19-9 pancreatic cancer. • Boron neutron capture therapy (BNCT) is a chemoradiotherapy using boron agents and neutron irradiation; the cancer accumulation capacity of boron agents is the key to its application in pancreatic cancer. • We successfully developed a boron-based drug targeting a glucose transporter that is highly expressed in pancreatic cancer. • BNCT using the sugar-binding boron drug developed in this study is a novel therapy as BNCT targeting pancreatic cancer with high CA19-9 levels. [ABSTRACT FROM AUTHOR]

Abstract: Replication-competent oncolytic viruses are being developed for human cancer therapy. We previously reported that an attenuated adenovirus OBP-301 (Telomelysin), in which the human telomerase reverse transcriptase promoter element drives expression of E1A and E1B genes linked with an internal ribosome entry site, could replicate in and causes selective lysis of human cancer cells. Infection efficiency in target cancer cells is the most important factor that predicts the antitumor effects of OBP-301. The objectives of this study are to examine the effects of the histone deacetylase inhibitor FR901228 on the level of coxsackie and adenovirus receptor (CAR) expression and OBP-301-mediated oncolysis in human non-small cell lung cancer cell lines. Flow cytometric analysis revealed up-regulated CAR expression in A549 and H460 cells following treatment with 1 ng/ml of FR901228, which was associated with increased infection efficiency as confirmed by replication-deficient β-galactosidase-expressing adenovirus vector. In contrast, neither CAR expression nor infection efficiency was affected by FR901228 in H1299 cells. To visualize and quantify viral replication in the presence of FR901228, we used OBP-401 (Telomelysin-GFP) that expresses the green fluorescent protein (GFP) reporter gene under the control of the cytomegalovirus promoter in the E3 region. Fluorescence microscopy and flow cytometry showed that FR901228 increased GFP expression in A549 and H460 cells following OBP-401 infection in a dose-dependent manner, but this effect did not occur in H1299 cells. In addition, OBP-301 and FR901228 demonstrated a synergistic antitumor effect in A549 cells in vitro, as confirmed by isobologram analysis. Our data indicate that FR901228 preferentially increases adenovirus infectivity via up-regulation of CAR expression, leading to a profound oncolytic effect, which may have a significant impact on the outcome of adenovirus-based oncolytic virotherapy. [Copyright &y& Elsevier]

Gene therapy was investigated as a promising treatment for cancer. However, low transduction efficiency limits the efficacy of gene therapy in clinics. We previously demonstrated that telomerase- specific replication-competent adenovirus (Telomelysin, OBP-301), in which the human telomerase reverse transcriptase (hTERT) promotor element drives expression of E1A and E1B genes linked with an IRES, induced selective E1 expression and efficient antitumor effect in human cancer cells, but not normal human fibroblasts. In this study, we evaluated the anticancer effect of the combination therapy of E1-deleted replication-deficient adenovirus expressing the wild-type p53 tumor suppressor gene (ADVEXIN, Ad-p53) and OBP-301 in human H1299 non-small cell lung cancer cells and SW620 colon cancer cells by using cell proliferation assay, immunoblotting, and cell-cycle analysis. We found that E1-deficient Ad-p53 could replicate in human cancer cells in the presence of OBP-301 and kill infected cells more efficiently than Ad-p53 alone or OBP-301 alone. Western Blotting Analysis demonstrated that OBP-301 plus Ad-p53 induced high levels of p53 protein expression, leading to cleavage of caspase-3 and poly(ADP-ribose) polymerase (PARP). In addition, flowcytometry showed that the sub-G1 population was dramatically increased with OBP-301 and Ad-p53 infection. The in vivo combination effect of intratumoral injection of Ad-p53 and OBP-301 in a human tumor xenograft model will be also reported. Our data demonstrate that OBP-301 in combination with Ad-p53 efficiently enhances antitumor activity, and provide the potential to affect the development of oncolytic virotherapy and gene therapy.Molecular Therapy (2006) 13, S114–S114; doi: 10.1016/j.ymthe.2006.08.353 [ABSTRACT FROM AUTHOR]

Oncolytic adenoviruses are being developed as novel anticancer therapeutics and currently undergoing clinical trials. We previously demonstrated that telomerase-specific replication-competent adenovirus (Telomelysin: OBP-301), in which the hTERT promoter regulates viral replication, efficiently killed human tumor cells. We further constructed OBP-401 (Telomelysin-GFP) that expresses the green fluorescent protein (GFP) reporter gene under the control of the cytomegalovirus promoter in the E3 region to monitor viral distribution. Here, we examined the feasibility of a single-agent therapy with OBP-401 as well as of combining OBP-401 with chemotherapeutic agents. Infection of OBP-401 alone or followed by the treatment of a chemotherapeutic drug, docetaxel (Taxotere), resulted in a profound in vitro cytotoxicity and GFP expression in various human cancer cell lines originating from different organs (lung, colon, esophagus, stomach, liver, and prostate), although the magnitude of antitumor effect varied among the cell types. Other chemotherapeutic drugs such as vinorelbine (Navelbine) and SN38 (the potent active metabolite of irinotecan) combined with OBP-401 also inhibited the growth of human cancer cells. Quantitative real-time PCR analysis demonstrated that docetaxel did not affect viral replication. For in vivo evaluation, nu/nu mice xenografted with H1299 human lung tumor received intratumoral injection of OBP-401 and intraperitoneal administration of docetaxel. Analysis of growth of implanted tumors showed a significant, therapeutic synergism, although OBP-401 alone and docetaxel alone showed modest inhibition of tumor growth. Thus, OBP-401 in combination with docetaxel efficiently enhances the antitumor efficacy both in vitro and in vivo, the outcome has important implications for tumor- specific oncolytic chemovirotherapies for human cancers.Molecular Therapy (2006) 13, S116–S116; doi: 10.1016/j.ymthe.2006.08.358 [ABSTRACT FROM AUTHOR]

Currently available methods for detection of tumors in vivo such as X-ray, computed tomography, ultrasonography, and magnetic resonance imaging are noninvasive and are well studied; the images, however, are not specific for tumors. Direct optical imaging of tumor cells in vivo that can clearly distinguish them from surrounding normal tissues may be clinically useful. Here we describe a new approach to visualizing tumors whose fluorescence can be detected using telomerase-specific replication-competent adenovirus expressing green fluorescent protein (GFP) (OBP-401, Telomelysin- GFP) and a charged-coupled device (CCD) imaging system. Human telomerase reverse transcriptase (hTERT) is the catalytic subunit of telomerase, which is highly active in cancer cells but quiescent in most normal somatic cells. OBP-401 contains the replication cassette, in which the hTERT promoter element drives expression of E1A and E1B genes linked with an IRES, and the GFP gene driven by the cytomegalovirus promoter for monitoring viral replication. Quantitative real time PCR analysis targeting the viral E1A sequence in vitro showed that OBP-401 replicated 5–6 logs by 3 days after infection in human cancer cell lines and coordinately induced GFP expression under fluorescence microscopy; OBP-401 replication, however, was attenuated up to 2 logs in normal human lung fibroblasts without GFP expression. We also found that established subcutaneous tumors could be visualized after intratumoral injection of OBP-401. Three weeks after treatment, tumors expressed strong green signals under a three-chip color cooled charged-coupled device camera. Tumor sections diffusely expressed GFP, suggesting in vivo viral replication and spread throughout the tumors. Finally, we examined whether OBP-401 might be useful for detection of lymph node metastasis in an orthotopic rectal cancer model. OBP-401 was intratumorally injected into HT29 tumors orthotopically implanted into the rectum in BALB/c nu/nu mice. Five days after injection, para-aortic lymph node metastasis could be visualized at laparotomy. Histological examination confirmed that GFP-positive lymph nodes contained microscopic metastasis. Our results indicate that intratumoral injection of OBP-401 causes viral spread into the regional lymphatic area and selectively replicates in neoplastic lesions, resulting in tumor-specific GFP expression. These observations suggest that intratumoral injection of OBP-401 might be a useful diagnostic method that provides a foundation for future clinical application.Molecular Therapy (2006) 13, S246–S246; doi: 10.1016/j.ymthe.2006.08.715 [ABSTRACT FROM AUTHOR]