A Phase 1 Study of Sapanisertib (TAK-228) in East Asian Patients with Advanced Nonhematological Malignancies.

BACKGROUND: Sapanisertib is an oral, highly selective inhibitor of mammalian target of rapamycin complexes 1 and 2. OBJECTIVE: The aim of this study was to assess the safety, tolerability, pharmacokinetics, preliminary efficacy, and to establish the recommended phase 2 dose (RP2D) of sapanisertib. PATIENTS AND METHODS: In this dose-escalation and expansion study, East Asian patients with nonhematologic malignancies received increasing sapanisertib doses once-daily (QD; starting at 2 mg) or once-weekly (QW; starting at 20 mg) in 28-day cycles. RESULTS: Among 28 patients (QD dosing, n = 22; QW dosing, n = 6), three dose-limiting toxicities were reported (stomatitis [n = 2], gastrointestinal inflammation, gingivitis, and acute myocardial infarction [all n = 1]), all in the 4 mg QD cohort. The RP2D of sapanisertib was 3 mg QD. The most common adverse events were stomatitis (64%), nausea (50%), and decreased appetite (50%) in the QD arm, and nausea (100%), blood alkaline phosphatase increased (67%), and hyperglycemia (67%) in the QW arm. The Tmax of sapanisertib was ~ 0.5-2.6 h and the T1/2 was ~ 5.9-7.6 h. Three patients achieved stable disease for ≥ 6 months (1 each in 3 mg QD, 4 mg QD and 20 mg QW cohorts, respectively); the clinical benefit rate was 45% and 67% in the QD and QW arms, respectively. CONCLUSIONS: The RP2D of sapanisertib in East Asian patients (3 mg QD) was lower than in Western patients (4 mg QD), but the pharmacokinetics and safety profiles were similar. Sapanisertib was well tolerated and showed moderate anti-tumor effects in heavily pretreated patients with nonhematologic malignancies. NCT NUMBER: NCT03370302; Registered December 7, 2017.

Safety, Tolerability, and Pharmacokinetics of TAK-931, a Cell Division Cycle 7 Inhibitor, in Patients with Advanced Solid Tumors: A Phase I First-in-Human Study.

Purpose: We conducted a first-in-human, dose-escalation study, to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics, and activity of TAK-931, a cell division cycle 7 inhibitor, in Japanese patients with advanced solid tumors. Experimental Design: Patients ages ≥20 years received oral TAK-931: once daily for 14 days in 21-day cycles (schedule A; from 30 mg); once daily or twice daily for 7 days on, 7 days off in 28-day cycles (schedule B; from 60 mg); continuous once daily (schedule D; from 20 mg); or once daily for 2 days on, 5 days off (schedule E; from 100 mg) in 21-day cycles. Results: Of the 80 patients enrolled, all had prior systemic treatment and 86% had stage IV disease. In schedule A, 2 patients experienced dose-limiting toxicities (DLTs) of grade 4 neutropenia and the maximum tolerated dose (MTD) was 50 mg. In schedule B, 4 patients experienced DLTs of grade 3 febrile neutropenia (n = 3) or grade 4 neutropenia (n = 1); the MTD was 100 mg. Schedules D and E were discontinued before MTD determination. The most common adverse events were nausea (60%) and neutropenia (56%). Time to maximum plasma concentration of TAK-931 was approximately 1-4 hours postdose; systemic exposure was approximately dose proportional. Posttreatment pharmacodynamic effects correlating to drug exposure were observed. Overall, 5 patients achieved a partial response. Conclusions: TAK-931 was tolerable with a manageable safety profile. TAK-931 50 mg once daily days 1-14 in 21-day cycles was selected as a recommended phase II dose and achieved proof of mechanism. Trial registration ID: NCT02699749. Significance: This was the first-in-human study of the CDC7 inhibitor, TAK-931, in patients with solid tumors. TAK-931 was generally tolerable with a manageable safety profile. The recommend phase II dose was determined to be TAK-931 50 mg administered once daily on days 1-14 of each 21-day cycle. A phase II study is ongoing to confirm the safety, tolerability, and antitumor activity of TAK-931 in patients with metastatic solid tumors.

Hematopoietic Stem Cell Transplantation and Brentuximab Vedotin for Patients with Relapsed or Refractory Hodgkin Lymphoma and Systemic Anaplastic Large-Cell Lymphoma.

Brentuximab vedotin (BV) is an antibody-drug conjugate that has demonstrated effectiveness as a monotherapy for patients with relapsed or refractory Hodgkin lymphoma and systemic anaplastic large-cell lymphoma via several clinical trials. Salvage chemotherapy followed by autologous or allogeneic hematopoietic stem cell transplantation (HSCT) has been performed as a second- or later-line regimen for improving the survival of patients with lymphoma. In particular, the effectiveness of autologous HSCT and the importance of achieving a complete response prior to autologous HSCT are established in Hodgkin lymphoma. Several clinical trials have reported that salvage chemotherapy followed by autologous HSCT showed high response rates, although significant treatment-related hematological toxicity was observed. In the present article, we review clinical reports for assessing the efficacy and safety of relatively less toxic BV as a bridging therapy before HSCT or as a consolidation therapy post-HSCT in patients with relapsed or refractory Hodgkin lymphoma or systemic anaplastic large-cell lymphoma. Generally, the reported BV regimens seem to be effective and well tolerated in such patients, and no significant influence of BV treatment is noted on hematopoietic stem cell harvest before HSCT. Large-scale clinical studies and long-term follow-up are expected to establish the safety and efficacy of these regimens.Funding: Takeda Pharmaceutical Co., Ltd., Tokyo, Japan.

Early detection of tumor relapse/regrowth by consecutive minimal residual disease monitoring in high-risk neuroblastoma patients.

Neuroblastoma is an aggressive pediatric tumor accounting for ~15% of cancer-associated mortalities in children. Despite the current intensive therapy, >50% of high-risk patients experience tumor relapse or regrowth caused by the activation of minimal residual disease (MRD). Although several MRD detection protocols using various reverse transcription-quantitative polymerase chain reaction (RT-qPCR) markers have been reported to evaluate the therapeutic response and disease status of neuroblastoma patients, their clinical significance remains elusive. The present study reports two high-risk neuroblastoma patients, whose MRD was consecutively monitored using 11 RT-qPCR markers (CHRNA3, CRMP1, DBH, DCX, DDC, GABRB3, GAP43, ISL1, KIF1A, PHOX2B and TH) during their course of treatment. The two patients initially responded to the induction therapy and reached MRD-negative status. The patients' MRD subsequently became positive with no elevation of their urinary homovanillic acid, urinary vanillylmandelic acid and serum neuron-specific enolase levels at 13 or 19 weeks prior to the clinical diagnosis of tumor relapse or regrowth. The present cases highlight the possibility of consecutive MRD monitoring using 11 markers to enable an early detection of tumor relapse or regrowth in high-risk neuroblastoma patients.

Collaboration of cancer-associated fibroblasts and tumour-associated macrophages for neuroblastoma development.

Neuroblastoma is the most common extracranial solid tumour in children and is histologically classified by its Schwannian stromal cells. Although having fewer Schwannian stromal cells is generally associated with more aggressive phenotypes, the exact roles of other stromal cells (mainly macrophages and fibroblasts) are unclear. Here, we examined 41 cases of neuroblastoma using immunohistochemistry for the tumour-associated macrophage (TAM) markers CD68, CD163, and CD204, and a cancer-associated fibroblast (CAF) marker, alpha smooth muscle actin (αSMA). Each case was assigned to low/high groups on the basis of the number of TAMs or three groups on the basis of the αSMA-staining area for CAFs. Both the number of TAMs and the area of CAFs were significantly correlated with clinical stage, MYCN amplification, bone marrow metastasis, histological classification, histological type, and risk classification. Furthermore, TAM settled in the vicinity of the CAF area, suggesting their close interaction within the tumour microenvironment. We next determined the effects of conditioned medium of a neuroblastoma cell line (NBCM) on bone marrow-derived mesenchymal stem cells (BM-MSCs) and peripheral blood mononuclear cell (PBMC)-derived macrophages in vitro. The TAM markers CD163 and CD204 were significantly up-regulated in PBMC-derived macrophages treated with NBCM. The expression of αSMA by BM-MSCs was increased in NBCM-treated cells. Co-culturing with CAF-like BM-MSCs did not enhance the invasive ability but supported the proliferation of tumour cells, whereas tumour cells co-cultured with TAM-like macrophages had the opposite effect. Intriguingly, TAM-like macrophages enhanced not only the invasive abilities of tumour cells and BM-MSCs but also the proliferation of BM-MSCs. CXCL2 secreted from TAM-like macrophages plays an important role in tumour invasiveness. Taken together, these results indicate that PBMC-derived macrophages and BM-MSCs are recruited to a tumour site and activated into TAMs and CAFs, respectively, followed by the formation of favourable environments for neuroblastoma progression. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Absolute lymphocyte count at the end of induction therapy is a prognostic factor in childhood acute lymphoblastic leukemia.

Recent studies have reported that the absolute lymphocyte count (ALC) during induction therapy is predictive of treatment outcome in de novo acute lymphoblastic leukemia (ALL); however, the significance of ALC on outcomes remains controversial. In the present study, we assessed the significance of ALC at day 29 (ALC-29), the end of induction therapy, on outcomes in our Japanese cohort. The outcomes of 141 patients aged ≤18 years with newly diagnosed ALL who were enrolled on the JACLS ALL-02 at our hospitals were analyzed in terms of ALC-29. Patients with ALC-29 ≥750/µL (n = 81) had a superior 5-year EFS (95.2 ± 2.7 vs 84.3 ± 4.8 %, P = 0.016) and OS (100 vs 87.0 ± 4.7 %, P = 0.0062). A multivariate analysis identified ALC-29 ≥750/µL as a significant predictor of improved EFS and OS after controlling for confounding factors. A multiple linear regression model revealed a significant inverse relationship between the percentage of blasts in bone marrow on day 15 and ALC-29 (P = 0.005). These results indicate that ALC is a simple prognostic factor in childhood ALL, and, thus, has the potential to refine current risk algorithms.

Sterility Testing of Stem Cell Products by Broad-Range Bacterial 16S Ribosomal DNA Polymerase Chain Reaction.

OBJECTIVE: To evaluate broad-range 16S ribosomal DNA (rDNA) polymerase chain reaction (PCR) as a rapid screening tool to detect bacterial contamination of stem-cell products. METHODS: We performed the evaluation using whole blood spiked with serially diluted bacterial-type strains. Detection sensitivity was defined as the bacterial concentration for which all replicates were positive at each concentration (100% detection). We tested the sterility of 29 bags of autologous peripheral blood stem cell (PBSC) products harvested at our facility using the 16S rDNA PCR method. RESULTS: The detection sensitivity of 16S rDNA PCR in spiked whole blood was 10¹ to 10² colony-forming units (CFU) per mL, depending on the bacterial strain. We detected no amplified 16S rDNA among the PBSCs we used in this study. The BacT/ALERT automated bacterial culture system that we used also showed no positive signals in any of the PBSCs tested. CONCLUSIONS: Our data indicate that bacterial 16S rDNA PCR is a useful alternative for rapid sterility testing, not only for blood products used in transfusion medicine but also for stem-cell products used in regenerative medicine.

Differential expression of minimal residual disease markers in peripheral blood and bone marrow samples from high-risk neuroblastoma patients.

Neuroblastoma is an aggressive solid tumor that leads to tumor relapse in more than half of high-risk patients. Minimal residual disease (MRD) is primarily responsible for tumor relapses and may be detected in peripheral blood (PB) and bone marrow (BM) samples. To evaluate the disease status and treatment response, a number of MRD detection protocols based on either common or distinct markers for PB and BM samples have been reported. However, the correlation between the expression of MRD markers in PB and BM samples remains elusive in the clinical samples. In the present study, the expression of 11 previously validated MRD markers (CHRNA3, CRMP1, DBH, DCX, DDC, GABRB3, GAP43, ISL1, KIF1A, PHOX2B and TH) was determined in 23 pairs of PB and BM samples collected from seven high-risk neuroblastoma patients at the same time point, and the sample was scored as MRD-positive if one of the MRD markers exceeded the normal range. Although the number of MRD-positive samples was not significantly different between PB and BM samples, the two most sensitive markers for PB samples (CRMP1 and KIF1A) were different from those for BM samples (PHOX2B and DBH). There was no statistically significant correlation between the expression of MRD markers in the PB and BM samples. These results suggest that MRD markers were differentially expressed in PB and BM samples from high-risk neuroblastoma patients.

The first report of adolescent TAFRO syndrome, a unique clinicopathologic variant of multicentric Castleman's disease.

BACKGROUND: TAFRO syndrome is a unique clinicopathologic variant of multicentric Castleman's disease that has recently been identified in Japan. It is characterized by a constellation of symptoms: Thrombocytopenia, Anasarca, reticulin Fibrosis of the bone marrow, Renal dysfunction and Organomegaly (TAFRO). Previous reports have shown that affected patients usually respond to immunosuppressive therapy, but the disease sometimes has a fatal course. TAFRO syndrome occurs in the middle-aged and elderly and there are no prior reports of the disease in adolescents. Here we report the first adolescent case, successfully treated with anti-IL-6 receptor antibody (tocilizumab, TCZ) and monitored with serial cytokine profiles. CASE PRESENTATION: A 15-year-old Japanese boy was referred to us with fever of unknown origin. Whole body computed tomography demonstrated systemic lymphadenopathy, organomegaly and anasarca. Laboratory tests showed elevated C-reactive protein and hypoproteinemia. Bone marrow biopsy revealed a hyperplastic marrow with megakaryocytic hyperplasia and mild reticulin fibrosis. Despite methylprednisolone pulse therapy, the disease progressed markedly to respiratory distress, acute renal failure, anemia and thrombocytopenia. Serum and plasma levels of cytokines, including IL-6, vascular endothelial growth factor, neopterin and soluble tumor necrosis factor receptors I and II, were markedly elevated. Repeated weekly TCZ administration dramatically improved the patient's symptoms and laboratory tests showed decreasing cytokine levels. CONCLUSION: To our knowledge, this is the first report of TAFRO syndrome in a young patient, suggesting that this disease can occur even in adolescence. The patient was successfully treated with TCZ. During our patient's clinical course, monitoring cytokine profiles was useful to assess the disease activity of TAFRO syndrome.

The emergence of CD20-/CD19- tumor cells after rituximab therapy for Epstein-Barr virus-associated post-transplant lymphoproliferative disorder complicated with hemophagocytic lymphohistiocytosis.

Post-transplant lymphoproliferative disorder (PTLD) is a well-recognized aggressive disease commonly associated with Epstein-Barr virus (EBV) infection after hematopoietic stem cell transplantation (HSCT). Although rituximab (RTX) is incorporated into the first-line therapy for EBV-PTLD patients, the outcome of the clinically overt disease is still not optimal mainly due to the regrowth of tumor cells. The proliferation of CD20-/CD19+ tumor cells is increasingly reported in RTX-treated EBV-PTLD patients, whereas the emergence of CD20-/CD19- tumor cells is barely recognized. Here, we report a fatal case of an 18-year-old patient who developed EBV-PTLD after allogeneic HSCT for anaplastic large-cell lymphoma. On day 60 after HSCT, the patient developed abdominal pain, watery diarrhea, and low-grade fever. Colon biopsy revealed the proliferation of CD20+/CD19+/EBV-encoded RNA (EBER)+ tumor cells, and an increase of EBV DNA was detected in peripheral blood (PB). He was treated with RTX for EBV-PTLD and was cleared of EBV DNA in PB. However, he manifested high-grade fever, pancytopenia, and elevated soluble interleukin-2 receptor with a prominent hemophagocytosis in bone marrow aspirates and was treated with etoposide for hemophagocytic lymphohistiocytosis (HLH) complication. He then developed EBV DNA positivity in PB and finally died of Bacteroides fragilis sepsis subsequent to bloody stool and ileus on day 163. Autopsy revealed erosion and bleeding in the whole colon with the proliferation of CD20-/CD19-/EBER+ tumor cells. Immunohistochemical analysis uncovered the CD3-/CD56-/CD79a+/CD79b+ B-cell origin of tumor cells. This case clinically demonstrates the removal of both CD20 and CD19 antigens from EBER+ B cells in an RTX-treated EBV-PTLD patient with HLH complication.

Primary pediatric stage III renal diffuse large B-cell lymphoma.

BACKGROUND: Although secondary renal involvement of non-Hodgkin lymphoma is frequently encountered, primary renal lymphoma is quite rare. We present a pediatric case of primary renal diffuse large B-cell lymphoma. CASE REPORT: A 12-year-old girl presenting with gross hematuria was referred to our hospital. Abdominal ultrasonography and imaging revealed a mass lesion in the superior pole of the right kidney. Serum creatinine and blood urea nitrogen levels were within normal ranges. Preoperative assessment of the mass indicated unspecified renal tumor. Right nephrectomy was performed and pathological examination showed diffuse large B-cell lymphoma. Postoperative fluorodeoxyglucose-positron emission tomography/computed tomography showed a small high-uptake lesion in the thyroid gland and aspiration cytology of the thyroid tumor demonstrated involvement of lymphoma, so stage III tumor diagnosed. After one course of chemotherapy, the patient achieved complete remission. She remains alive without disease, 3 years after completing a total of six courses of chemotherapy. CONCLUSIONS: Primary renal lymphoma is a very rare entity and preoperative diagnosis may be difficult. However, this entity is often reported to show clinically aggressive characteristics and therefore should be considered among the differential diagnoses for unusual renal tumors in pediatric patients.

Primary pediatric endobronchial Ewing sarcoma family of tumors.

BACKGROUND: Ewing sarcoma family of tumors is the second most common primary bone tumor of childhood. Extraosseous Ewing sarcoma family of tumors is rare. We present a pediatric case of primary endobronchial Ewing sarcoma family of tumors. CASE REPORT: A 12-year-old boy presented with dyspnea and chest radiography showed right pulmonary atelectasis. Chest computed tomography demonstrated tumor in the right main bronchus. Histopathological examination of the resected tumor demonstrated Ewing sarcoma family of tumors. No other lesions were detected throughout the body and the right main bronchus was thought to be the primary site. As of 1 year and 6 months after further resection of residual tumor followed by chemotherapy and radiotherapy, the patient remains disease-free. CONCLUSIONS: Extraosseous Ewing sarcoma family of tumors arises in soft tissues of the trunk or extremities, but primary endobronchial Ewing sarcoma family of tumors has rarely been reported. Although quite rare, Ewing sarcoma family of tumors should be considered among the differential diagnoses for pediatric bronchial tumor.

Minimal residual disease monitoring in neuroblastoma patients based on the expression of a set of real-time RT-PCR markers in tumor-initiating cells.

Minimal residual disease (MRD) is derived from tumor-initiating cells (TICs) and is responsible for tumor relapse. Neuroblastoma is characterized by extreme tumor heterogeneity, and more than half of high-risk patients experience tumor relapse. To overcome tumor heterogeneity and achieve more sensitive detection of MRD, several sets of real-time RT-PCR markers have been reported for MRD monitoring in neuroblastoma patients from different centers. However, these markers vary across centers and are still being validated. In the present study, we validated the ability of 14 commonly used real-time RT-PCR markers to detect MRD based on their expression in neuroblastoma TICs, and we developed a novel MRD detection protocol, which scored the samples as MRD-positive when the expression of one of the 11 real-time RT-PCR markers (CHRNA3, CRMP1, DBH, DCX, DDC, GABRB3, GAP43, ISL1, KIF1A, PHOX2B and TH) exceeded the normal range. By using this protocol, we prospectively monitored MRD in 73 bone marrow (BM), 12 peripheral blood stem cell and 8 peripheral blood samples from 14 neuroblastoma patients treated at a single center. We scored 100, 56, 56 and 57% BM cytology-positive, elevated vanillylmandelic acid (VMA), elevated homovanillic acid (HVA) and elevated neuron-specific enolase (NSE) samples as MRD-positive, respectively. MRD was also positive in 48, 45, 46 and 43% of the BM cytology-negative and normal VMA, normal HVA and normal NSE samples, respectively. These results suggest that the present MRD detection protocol based on the expression of a set of 11 real-time RT-PCR markers in neuroblastoma TICs achieves sensitive MRD monitoring in neuroblastoma patients.

Post-marketing surveillance of levofloxacin 0.5% ophthalmic solution for external ocular infections.

BACKGROUND: Levofloxacin 0.5% ophthalmic solution is an antibacterial formulation, which was approved and marketed for the treatment of ocular infections in Japan in 2000. OBJECTIVE: This study was designed to investigate the safety and efficacy of levofloxacin 0.5% ophthalmic solution in patients who received treatment for external ocular bacterial infections in regular clinical practice. METHODS: Patients were recruited from more than 800 medical facilities in Japan, in accordance with Japanese Ministry of Health, Labour and Welfare ordinance guidelines. They were followed during three distinct time periods: April 2000 to December 2001, January 2002 to June 2003, and July 2003 to December 2004. RESULTS: Information from 6760 patients receiving levofloxacin for the treatment of a variety of ocular infections was collected. Levofloxacin was well tolerated: adverse drug reactions (ADRs) were reported in 42 of 6686 patients (0.63%), with no serious ADRs reported. The most commonly reported ADRs were ocular disorders such as blepharitis, eye irritation, and punctate keratitis. The incidence of ADRs did not differ significantly with age, but it was significantly higher in females (0.82%) than in males (0.36%; p = 0.028). A clinical response was observed in 95.5% of patients receiving levofloxacin, with no difference in response between the three time periods. The rate of response to levofloxacin by bacterial disease ranged from 97.4% in keratitis to 88.3% in dacryocystitis. The rate was lower in patients with dacryocystitis, elderly patients, patients with a long duration of illness, and relapsing cases (all p < 0.001). CONCLUSION: This post-marketing surveillance of levofloxacin, conducted over 4 years, confirms the safety and efficacy of levofloxacin in regular clinical use and highlights that levofloxacin is a promising treatment for a variety of external ocular bacterial infections.

Place of death of pediatric cancer patients in a single institute during 7 years.

Place of death is an important issue at the end-of-life. It is poorly understood in pediatric cancer patients in Japan. This study aimed to clarify place of death of children with cancer as well as variables associated with place of death. Study population was pediatric cancer patients who died in the Department of Pediatrics at Kobe University Hospital during the last 7 years. The medical records were retrospectively reviewed regardless of cause of death to derive data relating to patients' characteristics and disease. 18 patients were included. Median age at death was 12.2 years old. 6 patients including 5 children in complete remission had hematological disease and 12 patients suffered from solid tumors. 4 patients (22.2%) died at home, whereas 14 patients (77.8%) died in the hospital including 6 ICU deaths. No one died in hospices. Preference of patients was unavailable due to the lack of inquiry. Factors influencing place of death (home, ICU, non-ICU) were disease (hematological disease vs. solid tumor, p=0.010, brain tumor vs. non-brain tumor, p=0.023), disease status (complete remission vs. non-complete remission, p=0.0014) and preference of families (p=0.029). Among 6 families who expressed preference, no disparity was observed between actual and preferred place of death. This is the first English publication of place of death of pediatric cancer patients in Japan. The low percentage of home death, factors influencing place of death and the lack of disparity between actual and preferred place of death were indicated. Further studies are required to better understand place of death.

Rab15 alternative splicing is altered in spheres of neuroblastoma cells.

Neuroblastoma is an aggressive pediatric tumor that accounts for 15% of cancer-related deaths in children. More than half of high-risk neuroblastoma patients develop tumor relapse that is lethal in most cases. A small population of tumor-initiating cells (TICs), recently identified from high-risk neuroblastoma patients as spheres, is believed to be responsible for tumor relapse. Rab family small G proteins are essential in controlling membrane traffic and their misregulation results in several cancers. Rab15 was originally isolated as a brain-specific Rab protein regulating the endocytic recycling pathway and was recently identified as a downstream target of the neural transcription factor Atoh1. Previously, we identified two alternatively spliced Rab15 isoforms in neuroblastoma cells and showed a significant correlation between Rab15 expression and neuronal differentiation. As aberrant alternative splicing is intimately associated with an increasing number of cancers, its use as a new diagnostic and/or prognostic biomarker has attracted considerable attention. In the present study, we explored cancer-associated changes of Rab15 alternative splicing in neuroblastoma TICs. We found that Rab15 alternative splicing generated two novel isoforms designated as Rab15(AN2) and Rab15(AN3) in addition to two known isoforms designated as Rab15(CN) and Rab15(AN1). Although both Rab15(AN2) and Rab15(AN3) contained premature termination codons, they were detected in not only neuroblastoma cells but also in normal human tissues. One isoform was predominantly expressed in the brain and testis, while the other isoform was more specifically expressed in the brain. In neuroblastoma, Rab15 isoform balance measured by the Rab15(CN)/Rab15(AN1+AN2+AN3) ratio was significantly decreased in spheres compared to parental cells. These results suggest that Rab15 alternative splicing may serve as a biomarker to discriminate TICs from non-TICs in neuroblastoma.

Epigallocatechin gallate inhibits sphere formation of neuroblastoma BE(2)-C cells.

OBJECTIVES: A growing number of epidemiological studies have demonstrated that the consumption of green tea inhibits the growth of a variety of cancers. Epigallocatechin gallate (EGCG), the most abundant catechin in green tea, has been shown to have an anti-cancer effect against many cancers. Most cancers are believed to be initiated from and maintained by a small population of tumor-initiating cells (TICs) that are responsible for chemotherapeutic resistance and tumor relapse. In neuroblastoma, an aggressive pediatric tumor that often relapses and has a poor prognosis, TICs were recently identified as spheres grown in a serum-free non-adherent culture used for neural crest stem cell growth. Although EGCG has been reported to induce growth arrest and apoptosis in neuroblastoma cells, its effect on neuroblastoma TICs remains to be defined. METHODS: Gene expression was analyzed by real-time reverse transcription polymerase chain reaction (RT-PCR). The effects of EGCG on cell proliferation, apoptosis, and sphere formation were determined by cell counting, propidium iodide staining, and sphere (>100 µm in diameter) counting, respectively. RESULTS: Neuroblastoma BE(2)-C cells showed increased expression of stem cell markers (nanog homeobox [NANOG] and octamer-binding transcription factor 4 [OCT4]), as well as decreased expression of neuronal differentiation markers (Cu(2+)-transporting ATPase alpha polypeptide [ATP7A] and dickkopf homolog 2 [DKK2]) in spheres grown in serum-free non-adherent culture, compared to parental cells grown in conventional culture. Although EGCG induced growth arrest and apoptosis in the parental cells in a dose-dependent manner, it was not effective against spheres. However, EGCG potently inhibited sphere formation in the BE(2)-C cells. CONCLUSIONS: The present results suggest that EGCG may inhibit the development of TICs in BE(2)-C cells.

Rab15 expression correlates with retinoic acid-induced differentiation of neuroblastoma cells.

Neuroblastoma is the most common extracranial solid tumor in children and accounts for 15% of pediatric cancer deaths. Although retinoic acid (RA) is currently used to treat high-risk neuroblastoma patients in the clinic, RA-responsiveness is variable and unpredictable. Since no alterations in the RA-signaling pathway have been found in neuroblastoma cells, molecules correlated with RA-induced differentiation will provide predictive markers of RA-responsiveness for clinical use. The Rab family of small G proteins are key regulators of membrane traffic and play a critical role in cell differentiation and cancer progression. Although an increasing number of cancer-associated alternative splicing events have been identified, alternative splicing of Rab proteins remains to be characterized in neuroblastoma. In the present study, we focused on Rab15 that was originally identified as a brain-specific Rab protein and regulates the endocytic recycling pathway. We identified alternatively spliced Rab15 isoforms designated as Rab15CN and Rab15AN in neuroblastoma cells. Rab15CN was composed of 7 exons encoding 212 amino acids and showed brain-specific expression. Alternative splicing of exon 4 generated Rab15AN that was predicted to encode 208 amino acids and was predominantly expressed in testis. RA induced neuronal differentiation of neuroblastoma BE(2)-C cells and specifically up-regulated Rab15CN expression. Reciprocally, RA-induced differentiation was observed in Rab15CN-expressing BE(2)-C cells in preference to Rab15AN-expressing BE(2)-C cells. Furthermore, Rab15CN expression was also specifically up-regulated during RA-induced differentiation of newly established neuroblastoma cells from high-risk patients. These results suggest that Rab15 expression correlates with RA-induced differentiation of neuroblastoma cells.