Yesenia Rojas

USP7 inhibitor P22077 inhibits neuroblastoma growth via inducing p53-mediated apoptosis

Neuroblastoma (NB) is a common pediatric cancer and contributes to more than 15% of all pediatric cancer-related deaths. Unlike adult tumors, recurrent somatic mutations in NB, such as tumor protein 53 (p53) mutations, occur with relative paucity. In addition, p53 downstream function is intact in NB cells with wild-type p53, suggesting that reactivation of p53 may be a viable therapeutic strategy for NB treatment. Herein, we report that the ubiquitin-specific protease 7 (USP7) inhibitor, P22077, potently induces apoptosis in NB cells with an intact USP7-HDM2-p53 axis but not in NB cells with mutant p53 or without human homolog of MDM2 (HDM2) expression. In this study, we found that P22077 stabilized p53 by inducing HDM2 protein degradation in NB cells. P22077 also significantly augmented the cytotoxic effects of doxorubicin (Dox) and etoposide (VP-16) in NB cells with an intact USP7-HDM2-p53 axis. Moreover, P22077 was found to be able to sensitize chemoresistant LA-N-6 NB cells to chemotherapy. In an in vivo orthotopic NB mouse model, P22077 significantly inhibited the xenograft growth of three NB cell lines. Database analysis of NB patients shows that high expression of USP7 significantly predicts poor outcomes. Together, our data strongly suggest that targeting USP7 is a novel concept in the treatment of NB. USP7-specific inhibitors like P22077 may serve not only as a stand-alone therapy but also as an effective adjunct to current chemotherapeutic regimens for treating NB with an intact USP7-HDM2-p53 axis.

Primary malignant pancreatic neoplasms in children and adolescents: A 20 year experience ☆

BACKGROUND Malignant pancreatic neoplasms in children and adolescents are rare. The clinical presentation, pathologic characteristics, management, and outcomes at two institutions are discussed. METHODS We retrospectively reviewed all pediatric patients (age <= 18 years) treated for malignant pancreatic neoplasms at two institutions between 1991 and 2011. RESULTS Thirty-one patients were identified with median age of 14.7 years (4-18 years). The most common histology was solid pseudopapillary tumor (SPT) (n=22, 71%) followed by neuroendocrine tumors (n=4, 13%), pancreatoblastoma (n=4, 13%), and one unclassified spindle cell neoplasm (3%). Most patients presented with abdominal pain (n=22, 71%). Complications included pancreatic leak, pseudocyst formation, pancreatitis, pancreatic insufficiency, and small bowel obstruction. The overall 1- and 5-year survival was 96% (95% CI 74%-99%) and 78% (95% CI 43%-93%). Median follow-up among patients alive at the end of follow-up was 20 months (<1 month-16.2 years). Patients with SPT had better overall survival compared to patients with neuroendocrine tumors or pancreatoblastomas (Log-rank; p=0.0143). CONCLUSION The majority of pediatric and adolescent patients present with SPTs which are usually resectable and associated with an excellent prognosis. Other histologic subtypes more often present with distant metastases and portend a worse prognosis.

A small-molecule inhibitor of UBE2N induces neuroblastoma cell death via activation of p53 and JNK pathways.

Neuroblastoma (NB) is the most common extracranial neoplasm in children. In NB, loss of p53 function is largely due to cytoplasmic sequestration rather than mutation. Ubiquitin-conjugating enzyme E2 N (UBE2N), also known as Ubc13, is an E2 ubiquitin-conjugating enzyme that promotes formation of monomeric p53 that results in its cytoplasmic translocation and subsequent loss of function. Therefore, inhibition of UBE2N may reactivate p53 by promoting its nuclear accumulation. Here, we show that NSC697923, a novel UBE2N inhibitor, exhibits potent cytotoxicity in a panel of NB cell lines evidenced by its ability to induce apoptosis. In p53 wild-type NB cells, NSC697923 induced nuclear accumulation of p53, which led to its increased transcriptional activity and tumor suppressor function. Interestingly, in p53 mutant NB cells, NSC697923 induced cell death by activating JNK pathway. This effect was reversible by blocking JNK activity with its selective inhibitor, SP600125. More importantly, NSC697923 impeded cell growth of chemoresistant LA-N-6 NB cell line in a manner greater than conventional chemotherapy drugs doxorubicin and etoposide. NSC697923 also revealed in vivo antitumor efficacy in NB orthotopic xenografts. Taken together, our results suggest that UBE2N is a potential therapeutic target in NB and provide a basis for the rational use of UBE2N inhibitors like NSC697923 as a novel treatment option for NB patients.

Primary malignant pulmonary tumors in children: a review of the national cancer data base

BACKGROUND The purpose is to delineate the clinical and pathological characteristics of rare primary malignant pulmonary tumors in children. METHODS Utilizing the National Cancer Data Base (NCDB), we analyzed all children (≤ 18 years) with a primary malignant pulmonary tumor from 1998 to 2011 to identify factors associated with better survival. RESULTS Of 211 children identified, the most common histology was carcinoid tumor (n=133, 63%) followed by mucoepidermoid carcinoma (MEC) (n=37, 18%), squamous cell carcinoma (SCC) (n=19, 9%), adenocarcinoma (n=16, 8%), bronchoalveolar carcinoma (BAC) (n=4, 2%), and small cell carcinoma (SCLC) (n=2, <1%). Factors that significantly affected survival include histology, race, tumor size, lymph node status, and extent of surgery. Patients with MEC and carcinoid tumors had a better overall survival compared to patients with other histologies (p<0.0001). The 5-year overall survival for MEC and carcinoid tumors was 100% and 95% (95% CI 87-98), respectively, versus 50% (95%CI 1-91) for BAC, 28% (95%CI 9-52) for SCC, and 26% (95%CI 5-55) for adenocarcinoma. CONCLUSION The majority of pediatric patients with a primary malignant pulmonary tumor present with carcinoid tumor or MEC and have an excellent prognosis. Lung cancers which are common in adults, but rare in children, have a worse prognosis.

NSC-87877 inhibits DUSP26 function in neuroblastoma resulting in p53-mediated apoptosis

Dual specificity protein phosphatase 26 (DUSP26) is overexpressed in high-risk neuroblastoma (NB) and contributes to chemoresistance by inhibiting p53 function. In vitro, DUSP26 has also been shown to effectively inhibit p38 MAP kinase. We hypothesize that inhibiting DUSP26 will result in decreased NB cell growth in a p53 and/or p38-mediated manner. NSC-87877 (8-hydroxy-7-[(6-sulfo-2-naphthyl)azo]-5-quinolinesulfonic acid), a novel DUSP26 small molecule inhibitor, shows effective growth inhibition and induction of apoptosis in NB cell lines. NB cell lines treated with small hairpin RNA (shRNA) targeting DUSP26 also exhibit a proliferation defect both in vitro and in vivo. Treatment of NB cell lines with NSC-87877 results in increased p53 phosphorylation (Ser37 and Ser46) and activation, increased activation of downstream p38 effector proteins (heat shock protein 27 (HSP27) and MAP kinase-activated protein kinase 2 (MAPKAPK2)) and poly ADP ribose polymerase/caspase-3 cleavage. The cytotoxicity resulting from DUSP26 inhibition is partially reversed by knocking down p53 expression with shRNA and also by inhibiting p38 activity with SB203580 (4-[4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-1H-imidazol-5-yl]pyridine). In an intrarenal mouse model of NB, NSC-87877 treatment results in decreased tumor growth and increased p53 and p38 activity. Together, these results suggest that DUSP26 inhibition with NSC-87877 is an effective strategy to induce NB cell cytotoxicity in vitro and in vivo through activation of the p53 and p38 mitogen-activated protein kinase (MAPK) tumor-suppressor pathways.

Extrarenal Wilms tumor: a case report and review of the literature

Extrarenal Wilms tumors are extremely rare with only isolated case reports in the pediatric literature. We present the case of a 2-year old boy who presented with a large abdominal mass and constipation. Pathologic diagnosis of the tumor was extrarenal Wilms tumor (ERWT) with favorable histology. We discuss the diagnostic workup, radiologic and operative findings, treatment and review of the literature.

Focal nodular hyperplasia in children: An institutional experience with review of the literature

BACKGROUND Focal nodular hyperplasia (FNH) is uncommonly diagnosed in pediatric patients and may be difficult to distinguish from a malignancy. We present a review of all children with a tissue diagnosis of FNH at our institution, describe the diagnostic modalities, and provide recommendations for diagnosis and follow-up based on our experience and review of the literature. METHODS A retrospective review of children <18years of age diagnosed with FNH at a single institution was performed from 2000 to 2013. RESULTS Twelve patients were identified with a tissue diagnosis of FNH. Two patients required surgical resection of their lesion owing to concern for malignancy. Ten patients were managed expectantly with imaging surveillance after biopsy confirmed a diagnosis of FNH. All patients who underwent MRI had very typical findings including hypointensity on T1 weighted sequences, hyperintensity on T2, and homogenous uptake of contrast on the arterial phase. On follow-up all patients had either a stable lesion or reduction in size. CONCLUSIONS Focal nodular hyperplasia presents typically in children with liver disease, have undergone chemotherapy, and adolescent females. Young children, particularly <5years of age, without underlying liver disease or history of chemotherapy can pose a diagnostic dilemma. In this unique subgroup of children with FNH, MRI and/or needle biopsy should be adequate diagnostic modalities for these lesions.

Characteristics and outcomes in children with undifferentiated embryonal sarcoma of the liver: A report from the National Cancer Database.

To examine patient characteristics and outcomes in children with undifferentiated embryonal sarcoma of the liver (UESL) using a multi‐institutional database.

EWS-FLI1 and RNA helicase A interaction inhibitor YK-4-279 inhibits growth of neuroblastoma

Treatment failure in high risk neuroblastoma (NB) is largely due to the development of chemotherapy resistance. We analyzed the gene expression changes associated with exposure to chemotherapy in six high risk NB tumors with the aid of the Connectivity Map bioinformatics platform. Ten therapeutic agents were predicted to have a high probability of reversing the transcriptome changes associated with neoadjuvant chemotherapy treatment. Among these agents, initial screening showed the EWS-FLI1 and RNA helicase A interaction inhibitor YK-4-279, had obvious cytotoxic effects on NB cell lines. Using a panel of NB cell lines, including MYCN nonamplified (SK-N-AS, SH-SY5Y, and CHLA-255), and MYCN amplified (NB-19, NGP, and IMR-32) cell lines, we found that YK-4-279 had cytotoxic effects on all lines tested. In addition, YK-4-279 also inhibited cell proliferation and anchorage-independent growth and induced cell apoptosis of these cells. YK-4-279 enhanced the cytotoxic effect of doxorubicin (Dox). Moreover, YK-4-279 was able to overcome the established chemoresistance of LA-N-6 NB cells. In an orthotopic xenograft NB mouse model, YK-4-279 inhibited NB tumor growth and induced apoptosis in tumor cells through PARP and Caspase 3 cleavage in vivo. While EWS-FLI1 fusion protein is not frequently found in NB, using the R2 public database of neuroblastoma outcome and gene expression, we found that high expression of EWSR1 was associated with poor patient outcome. Knockdown of EWSR1 inhibited the oncogenic potential of neuroblastoma cell lines. Taken together, our results indicate that YK-4-279 might be a promising agent for treatment of NB that merits further exploration.

The optimal timing of surgical resection in high-risk neuroblastoma

BACKGROUND While most high-risk neuroblastoma (HRNB) patients are enrolled in cooperative group or institutional protocols, variability exists within these protocols as to when surgical resection of the primary tumor should be performed after neoadjuvant induction chemotherapy. We sought to determine if the number of chemotherapy cycles prior to surgery affects surgical or survival outcomes in HRNB patients. METHODS We performed a retrospective review of all HRNB patients <18years of age from 2000 to 2010, at Texas Childrens Hospital. Patients were stratified based on the number of neoadjuvant induction chemotherapy cycles prior to surgical resection. Pre and post- chemotherapy tumor size, MYCN status, iodine-131-metaiodobenzylguanidine (MIBG) score at diagnosis, extent of surgical resection, estimated surgical blood loss, post-operative outcomes, and event free (EFS) and overall survival (OS) were evaluated. Data were analyzed using Wilcoxon rank-sum test, Kruskal-Wallis test, Fishers exact test, Kaplan-Meier analyses, and Cox regression analyses. P-value <0.05 was considered significant. RESULTS Data from 50 patients with HRNB were analyzed. Patients were stratified by the number of cycles of chemotherapy received prior to surgery. Six patients received 2cycles of chemotherapy (12%), 20 patients received 3cycles (40%), 13 patients received 4cycles (26%), and 11 patients received 5cycles (22%) prior to surgical resection of the primary tumor. The 5-year OS was 33%, 45%, 83% and 36% in patients who received 2, 3, 4 and 5cycles of chemotherapy prior to surgery, respectively (p=0.07). Multivariate analysis revealed that patients who received 4cycles of chemotherapy had a significantly lower mortality (HR: 0.11, 95% CI: 0.01-0.87, p=0.04) compared to those with 2cycles of chemotherapy. Among the different cohorts, there were no differences with respect to MYCN status, MIBG score at diagnosis, incidence of bone marrow metastasis, extent of surgical resection, estimated blood loss, incidence of post-operative complications, or length of stay. CONCLUSION HRNB patients who receive 4cycles of chemotherapy prior to surgical resection have a superior OS than patients who receive 2. Based on the superior survival of patients who received 4cycles of chemotherapy prior to surgery, further studies are warranted to elucidate these differences.