Rhabdomyosarcoma: new windows of opportunity

Precision Medicine Highlights Dysregulation of the CDK4/6 Cell Cycle Regulatory Pathway in Pediatric, Adolescents and Young Adult Sarcomas

Simple Summary

This review provides an overview of clinical features and current therapies in children, adolescents, and young adults (AYA) with sarcoma. It highlights the basic and clinical findings on the cyclin-dependent kinases 4 and 6 (CDK4/6) cell cycle regulatory pathway in the context of the precision medicine-based molecular profiles of the three most common types of pediatric and AYA sarcomas—osteosarcoma (OS), rhabdomyosarcoma (RMS), and Ewing sarcoma (EWS).

Abstract

Despite improved therapeutic and clinical outcomes for patients with localized diseases, outcomes for pediatric and AYA sarcoma patients with high-grade or aggressive disease are still relatively poor. With advancements in next generation sequencing (NGS), precision medicine now provides a strategy to improve outcomes in patients with aggressive disease by identifying biomarkers of therapeutic sensitivity or resistance. The integration of NGS into clinical decision making not only increases the accuracy of diagnosis and prognosis, but also has the potential to identify effective and less toxic therapies for pediatric and AYA sarcomas. Genome and transcriptome profiling have detected dysregulation of the CDK4/6 cell cycle regulatory pathway in subpopulations of pediatric and AYA OS, RMS, and EWS. In these patients, the inhibition of CDK4/6 represents a promising precision medicine-guided therapy. There is a critical need, however, to identify novel and promising combination therapies to fight the development of resistance to CDK4/6 inhibition. In this review, we offer rationale and perspective on the promise and challenges of this therapeutic approach.

[Clinical analysis of testicular rhabdomyosarcoma]

Testicular rhabdomyosarcoma is relatively rare in testicular tumors, but the age of patient is relatively young and the degree of malignancy is high. Therefore, this article introduces 4 cases of testicular rhabdomyosarcoma who were admitted to Peking University Third Hospital from May 1994 to February 2019, and reviews the literature to improve the diagnosis and treatment of this disease. The average age of the 4 patients was 17.5 years (14-21 years), the average hospital stay was 22.0 d (17-31 d), and the average body mass index was 19.6 kg/m² (14.7-25.8 kg/m²). All the patients underwent routine preoperative blood and urine routine, biochemical tests, as well as serum tumor markers. Preoperative examinations also included chest radiograph, electrocardiogram, ultrasound of the scrotum and groin, and abdominal enhanced CT. Lung CT or other examinations were performed if necessary. The median serum human chorionic gonadotropin (HCG) of the 4 patients was 0.20 IU/L (0.06-0.86 IU/L) (all normal), and the median serum alpha-fetoprotein (AFP) was 1.03 g/L (0.65-1.66 g/L) (all normal). The average maximum diameter of the tumor was 10.0 cm (4.5-15.0 cm). Testicular rhabdomyosarcoma was mainly diagnosed by pathology. The main treatment was radical orchiectomy combined with retroperitoneal lymph node dissection, with or without postoperative adjuvant chemotherapy. The clinical manifestations of the patients with testicular rhabdomyosarcoma had no specific characteristics, but most patients were young at onset with mainly painless masses in the testicles, which were already large when they were found. Patients with testicular rhabdomyosarcoma have a poor prognosis, most of whom recur within two years. Because of the small number of cases of testicular rhabdomyosarcoma, there is no standard treatment currently. It is recommended that patients with testicular rhabdomyosarcoma undergo radical testicular resection combined with retroperitoneal lymph node dissection. Retroperitoneal lymph node metastasis is an important prognostic factor, and patients with postoperative adjuvant chemotherapy can still survive for a longer time. If local recurrence or limited metastasis is found after operation, local resection and salvage radiotherapy are feasible.

Flavonoids kaempferol and quercetin are nuclear receptor 4A1 (NR4A1, Nur77) ligands and inhibit rhabdomyosarcoma cell and tumor growth

BACKGROUND

Flavonoids exhibit both chemopreventive and chemotherapeutic activity for multiple tumor types, however, their mechanisms of action are not well defined. Based on some of their functional and gene modifying activities as anticancer agents, we hypothesized that kaempferol and quercetin were nuclear receptor 4A1 (NR4A1, Nur77) ligands and confirmed that both compounds directly bound NR4A1 with KD values of 3.1 and 0.93 μM, respectively.

METHODS

The activities of kaempferol and quercetin were determined in direct binding to NR4A1 protein and in NR4A1-dependent transactivation assays in Rh30 and Rh41 rhabdomyosarcoma (RMS) cells. Flavonoid-dependent effects as inhibitors of cell growth, survival and invasion were determined in XTT and Boyden chamber assays respectively and changes in protein levels were determined by western blots. Tumor growth inhibition studies were carried out in athymic nude mice bearing Rh30 cells as xenografts.

RESULTS

Kaempferol and quercetin bind NR4A1 protein and inhibit NR4A1-dependent transactivation in RMS cells. NR4A1 also regulates RMS cell growth, survival, mTOR signaling and invasion. The pro-oncogenic PAX3-FOXO1 and G9a genes are also regulated by NR4A1 and, these pathways and genes are all inhibited by kaempferol and quercetin. Moreover, at a dose of 50 mg/kg/d kaempferol and quercetin inhibited tumor growth in an athymic nude mouse xenograft model bearing Rh30 cells.

CONCLUSION

These results demonstrate the clinical potential for repurposing kaempferol and quercetin for clinical applications as precision medicine for treating RMS patients that express NR4A1 in order to increase the efficacy and decrease dosages of currently used cytotoxic drugs.

A review of the biological activity and pharmacology of cryptotanshinone, an important active constituent in Danshen

Cryptotanshinone (IUPAC name: (R)-1,2,6,7,8,9-hexahydro-1,6,6-trimethyl-phenanthro(1,2-b)furan-10,11-dione), a biologically active constituent extracted from the roots and rhizomes of the plant Salvia miltiorrhiza, has been studied in depth as a medicinally active compound and shown to have efficacy in the treatment of numerous diseases and disorders. In this review, we describe in detail the current status of cryptotanshinone research, including findings relating to the structure, pharmacokinetics, pharmacological activity, and derivatives of this compound. Cryptotanshinoneh as a diverse range of pharmacological effects, including anti-cancer, anti-inflammatory, immune regulatory, neuroprotective, and anti-fibrosis activities. Studies on the molecular mechanisms underlying the activities of cryptotanshinone have established that the JAK2/STAT3, PI3K/AKT, NF-κB, AMPK, and cell cycle pathways are involved in the inhibitory and pro-apoptotic effects of cryptotanshinone on different tumor cell lines, these molecular pathways interact in a coordinated manner to inhibit cell proliferation, migration and invasion,and induce transformation, autophagy, necrosis, and cellular immunity. The anti-inflammatory mechanisms of cryptotanshinone have been found to be associated with the TLR4-MyD88/PI3K/Nrf2 and TLR4-MyD88/NF-κB/MAPK pathways, whereasthe Hedgehog, NF-κB, and Nrf-2/HO-1 pathways are regulated by cryptotanshinone to reduce organ fibrosis, and its inhibitory effects on the PI3K/AKT-eNOS pathway have been linked to neuroprotective effects. Given the potential medicinal utility of cryptotanshinone, further research is needed to verify the efficacy and safety of this compound in clinical use, evaluate its pharmacological activity, and identify molecular targets.

Pathogenic Germline Variants in Cancer Susceptibility Genes in Children and Young Adults With Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common pediatric soft-tissue sarcoma and accounts for 3% of all pediatric cancer. In this study, we investigated germline sequence and structural variation in a broad set of genes in two large, independent RMS cohorts.

MATERIALS AND METHODS

Genome sequencing of the discovery cohort (n = 273) and exome sequencing of the secondary cohort (n = 121) were conducted on germline DNA. Analyses were performed on 130 cancer susceptibility genes (CSG). Pathogenic or likely pathogenic (P/LP) variants were predicted using the American College of Medical Genetics and Genomics (ACMG) criteria. Structural variation and survival analyses were performed on the discovery cohort.

RESULTS

We found that 6.6%-7.7% of patients with RMS harbored P/LP variants in dominant-acting CSG. An additional approximately 1% have structural variants (ATM, CDKN1C) in CSGs. CSG variants did not influence survival, although there was a significant correlation with an earlier age of tumor onset. There was a nonsignificant excess of P/LP variants in dominant inheritance genes in the patients with FOXO1 fusion-negative RMS patients versus the patients with FOXO1 fusion-positive RMS. We identified pathogenic germline variants in CSGs previously (TP53, NF1, DICER1, mismatch repair genes), rarely (BRCA2, CBL, CHEK2, SMARCA4), or never (FGFR4) reported in RMS. Numerous genes (TP53, BRCA2, mismatch repair) were on the ACMG Secondary Findings 2.0 list.

CONCLUSION

In two cohorts of patients with RMS, we identified pathogenic germline variants for which gene-specific therapies and surveillance guidelines may be beneficial. In families with a proband with an RMS-risk P/LP variant, genetic counseling and cascade testing should be considered, especially for ACMG Secondary Findings genes and/or with gene-specific surveillance guidelines.

Pharmacologic Inhibition of Ezrin-Radixin-Moesin Phosphorylation is a Novel Therapeutic Strategy in Rhabdomyosarcoma

Intermediate and high-risk rhabdomyosarcoma (RMS) patients have poor prognosis with available treatment options, highlighting a clear unmet need for identification of novel therapeutic strategies. Ezrin-radixin-moesin (ERM) family members are membrane-cytoskeleton linker proteins with well-defined roles in tumor metastasis, growth, and survival. ERM protein activity is regulated by dynamic changes in the phosphorylation at a conserved threonine residue in their C-terminal actin-binding domain. Interestingly, ERM family member, ezrin, has elevated expression in the RMS tissue. Despite this, the translational scope of targeting ERM family proteins in these tumors through pharmacological inhibition has never been considered. This study investigates the inhibition of ERM phosphorylation using a small molecule pharmacophore NSC668394 as a potential strategy against RMS. Upon in vitro treatment with NSC668394, RMS cells exhibit a dose-dependent decrease in cell viability and proliferation, with induction of caspase-3 cleavage and apoptosis. siRNA-mediated knockdown of individual ERM protein expression revealed that each regulates RMS survival to a different degree. In vivo administration of NSC668394 in RMS xenografts causes significant decrease in tumor growth, with no adverse effect on body weight. Collectively, this study highlights the importance of the active conformation of ERM proteins in RMS progression and survival and supports pharmacologic inhibition of these proteins as a novel therapeutic approach.

Preclinical rationale for entinostat in embryonal rhabdomyosarcoma

BACKGROUND

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in the pediatric cancer population. Survival among metastatic RMS patients has remained dismal yet unimproved for years. We previously identified the class I-specific histone deacetylase inhibitor, entinostat (ENT), as a pharmacological agent that transcriptionally suppresses the PAX3:FOXO1 tumor-initiating fusion gene found in alveolar rhabdomyosarcoma (aRMS), and we further investigated the mechanism by which ENT suppresses PAX3:FOXO1 oncogene and demonstrated the preclinical efficacy of ENT in RMS orthotopic allograft and patient-derived xenograft (PDX) models. In this study, we investigated whether ENT also has antitumor activity in fusion-negative eRMS orthotopic allografts and PDX models either as a single agent or in combination with vincristine (VCR).

METHODS

We tested the efficacy of ENT and VCR as single agents and in combination in orthotopic allograft and PDX mouse models of eRMS. We then performed CRISPR screening to identify which HDAC among the class I HDACs is responsible for tumor growth inhibition in eRMS. To analyze whether ENT treatment as a single agent or in combination with VCR induces myogenic differentiation, we performed hematoxylin and eosin (H&E) staining in tumors.

RESULTS

ENT in combination with the chemotherapy VCR has synergistic antitumor activity in a subset of fusion-negative eRMS in orthotopic "allografts," although PDX mouse models were too hypersensitive to the VCR dose used to detect synergy. Mechanistic studies involving CRISPR suggest that HDAC3 inhibition is the primary mechanism of cell-autonomous cytoreduction in eRMS. Following cytoreduction in vivo, residual tumor cells in the allograft models treated with chemotherapy undergo a dramatic, entinostat-induced (70-100%) conversion to non-proliferative rhabdomyoblasts.

CONCLUSION

Our results suggest that the targeting class I HDACs may provide a therapeutic benefit for selected patients with eRMS. ENT's preclinical in vivo efficacy makes ENT a rational drug candidate in a phase II clinical trial for eRMS.

The histone deacetylase inhibitor Suberoylanilide Hydroxamic Acid (SAHA) as a therapeutic agent in rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is an aggressive childhood sarcoma with two distinct subtypes, embryonal (ERMS) and alveolar (ARMS) histologies. More effective treatment is needed to improve outcomes, beyond conventional cytotoxic chemotherapy. The pan-histone deacetylase inhibitor, Suberoylanilide Hydroxamic Acid (SAHA), has shown promising efficacy in limited preclinical studies. We used a panel of human ERMS and ARMS cell lines and xenografts to evaluate the effects of SAHA as a therapeutic agent in both RMS subtypes. SAHA decreased cell viability by inhibiting S-phase progression in all cell lines tested, and induced apoptosis in all but one cell line. Molecularly, SAHA-treated cells showed activation of a DNA damage response, induction of the cell cycle inhibitors p21^Cip1 and p27^Kip1 and downregulation of Cyclin D1. In a subset of RMS cell lines, SAHA promoted features of cellular senescence and myogenic differentiation. Interestingly, SAHA treatment profoundly decreased protein levels of the driver fusion oncoprotein PAX3-FOXO1 in ARMS cells at a post-translational level. In vivo, SAHA-treated xenografts showed increased histone acetylation and induction of a DNA damage response, along with variable upregulation of p21^Cip1 and p27^Kip1. However, while the ARMS Rh41 xenograft tumor growth was significantly inhibited, there was no significant inhibition of the ERMS tumor xenograft RD. Thus, our work shows that, while SAHA is effective against ERMS and ARMS tumor cells in vitro, it has divergent in vivo effects . Together with the observed effects on the PAX3-FOXO1 fusion protein, these data suggest SAHA as a possible therapeutic agent for clinical testing in patients with fusion protein-positive RMS.

Outcome of 449 adult patients with rhabdomyosarcoma: an observational ambispective nationwide study

Five-year overall survival (OS) of localized RMS exceeds 70% in children (<18) but is very poor in adult patients. We analyzed the outcome and prognostic factors (PF) of a national series of adult patients with RMS in a large study. The study population consisted of two different cohorts: a retrospective cohort (157 adult patients treated in 13 reference centers between 05/1981 and 02/2010) and the prospective cohort (292 patients with RMS diagnosed and treated between 01/2010 and 12/2014 in France) included in the NetSarc database. A descriptive analysis of patients' characteristics and prognostic factors was conducted on both series which were compared. In the retrospective series, histological subtypes were embryonal (E-RMS) for 21% of patients, alveolar (A-RMS) for 35% of patients, and "adult-type" P-RMS (pleomorphic, spindle cell RMS, not otherwise specified) (P) for 44% patients. This distribution significantly differed in the prospective cohort: A-RMS: 18%; E-RMS: 17%; and P-RMS 65%. With a median follow-up of 8.5 years, 5-year OS for localized RMS and advanced RMS (with nodes and/or metastases) was 43% and 5%, respectively, (P < 0.0001), and median OS was 51, 33, and 16 months for E-RMS, A-RMS, and P-RMS, respectively, in the retrospective cohort. The median OS was less than 40 months for the prospective nationwide cohort for the entire population. In a multivariate analysis of the retrospective study, independent prognostic factors for OS were A-RMS, R0 resection, and adjuvant radiotherapy (RT). For localized RMS, age and use of pediatric chemotherapy (CT) regimen are independent prognostic factors. Adult patients with RMS have a poorer overall survival than pediatric patients, and survival varies considerably across histological subtypes.

Giant intrascrotal embryonal rhabdomyosarcoma in an adult: a case report and review of the literature

Background

Intrascrotal embryonal rhabdomyosarcoma in adults is a rare tumor with high aggression and a poor prognosis. We report our patient’s case and review the relevant literature to improve the understanding of this rare disease.

Case presentation

A 21-year-old Han Chinese man presented to our hospital with a right intrascrotal mass of 1 year’s duration. His physical examination revealed an enlarged right scrotum containing a huge tender mass measuring about 10 × 7 cm. Ordinary and contrast-enhanced ultrasonography showed a solid mass in the right scrotum, which was suspected to be a malignant tumor. An abdominopelvic computed tomographic scan revealed metastases in the retroperitoneal lymph nodes. The patient was diagnosed with malignant testicular tumor and underwent a right radical orchiectomy by an inguinal approach. Postoperative pathological examination suggested an intrascrotal embryonal rhabdomyosarcoma.

Conclusions

Intrascrotal embryonal rhabdomyosarcoma is a rare but highly aggressive tumor. Clinical and imaging manifestations of this tumor are nonspecific, so the definitive diagnosis depends on postoperative pathology and immunohistochemistry. Early suspicion, radical orchiectomy, accurate pathologic diagnosis, and adjuvant chemotherapy and/or radiotherapy are the keys to optimal prognosis.

NFκB signaling in alveolar rhabdomyosarcoma

Alveolar rhabdomyosarcoma (aRMS) is a pediatric soft tissue cancer commonly associated with a chromosomal translocation that leads to the expression of a Pax3:Foxo1 or Pax7:Foxo1 fusion protein, the developmental underpinnings of which may give clues to its therapeutic approaches. In aRMS, the NFκB–YY1–miR-29 regulatory circuit is dysregulated, resulting in repression of miR-29 and loss of the associated tumor suppressor activity. To further elucidate the role of NFκB in aRMS, we first tested 55 unique sarcoma cell lines and primary cell cultures in a large-scale chemical screen targeting diverse molecular pathways. We found that pharmacological inhibition of NFκB activity resulted in decreased cell proliferation of many of the aRMS tumor cultures. Surprisingly, mice that were orthotopically allografted with aRMS tumor cells exhibited no difference in tumor growth when administered an NFκB inhibitor, compared to control. Furthermore, inhibition of NFκB by genetically ablating its activating kinase inhibitor, IKKβ, by conditional deletion in a mouse model harboring the Pax3:Foxo1 chimeric oncogene failed to abrogate spontaneous tumor growth. Genetically engineered mice with conditionally deleted IKKβ exhibited a paradoxical decrease in tumor latency compared with those with active NFκB. However, using a synthetic-lethal approach, primary cell cultures derived from tumors with inactivated NFκB showed sensitivity to the BCL-2 inhibitor navitoclax. When used in combination with an NFκB inhibitor, navitoclax was synergistic in decreasing the growth of both human and IKKβ wild-type mouse aRMS cells, indicating that inactivation of NFκB alone may not be sufficient for reducing tumor growth, but, when combined with another targeted therapeutic, may be clinically beneficial.

Summary: In a genetically engineered mouse model of aRMS, disrupting the NFκB pathway facilitated tumor initiation, suggesting it is a modifier of the disease rather than the driver.

Rhabdomyosarcoma: an overview and nursing considerations

This article aims to provide nurses with a clinical overview of rhabdomyosarcoma, a rare type of soft tissue sarcoma. The causes, clinical features, pathophysiology, diagnostic process, prognosis and treatment will be explored. Some of the main nursing considerations for rhabdomyosarcoma patients will be discussed in light of current treatment recommendations.

Treatment and outcome of patients with localized intrathoracic and chest wall rhabdomyosarcoma: a report of the Cooperative Weichteilsarkom Studiengruppe (CWS)

PURPOSE

Rhabdomyosarcoma (RMS) is the most common pediatric soft tissue sarcoma. In 7% of the cases it is localized at the chest wall or intrathoracically. The aim of this study was to analyze the multimodal treatment concepts and outcomes of children suffering from intrathoracic and chest wall RMS treated within three different Cooperative Soft Tissue Sarcoma (CWS) trials and one registry (Soft Tissue Sarcoma Registry, SoTiSaR).

METHODS

Data of 51 patients with thoracic RMS enrolled in three different CWS trials (CWS-86, -91, -2002P) and one registry (SoTiSaR) were analyzed retrospectively. Surgery and its influence on outcome were assessed. Median follow-up was 37.5 months (0.9-152.5).

RESULTS

Median age of the patients was 8.8 years (range 0-19 years). The 5-year overall survival rate (OS) was 57% (95%-CI 49-65) and the 5-year event-free survival rate (EFS) was 45% (38-52). Thirty-five patients had tumors located at the chest wall (EFS: 51%, 43-59), and 16 patients had intrathoracic tumors (EFS: 26%, 13-39). Seventeen patients with tumors ≤ 5 cm had a better outcome (EFS: 64%, 52-76) compared to patients with tumors larger than 5 cm (EFS: 36%, 27-45). Radiotherapy (RT) significantly improved the survival of patients with alveolar RMS compared to patients with embryonal histology (EFS: 66%, 52-80 vs. 32%, 21-43 p = 0.02). Complete tumor excision during delayed surgery was the main prognostic factor for survival (p = 0.045).

CONCLUSION

Thoracic RMS is a rare tumor entity. Completeness of tumor resection significantly improved survival of the patients.

Characteristics of bladder neoplasms in the young population of Saudi Arabia

Context:

Bladder neoplasms are a well-studied subject in medicine. However, the evidence of bladder neoplasms in children and the young adult population (≤40 years), particularly in Saudi Arabia, is lacking.

Aims:

The aims of this study were to identify histopathological characteristics as well as clinical features, prognosis, and treatment of bladder neoplasms in this age group in a single tertiary referral center, Riyadh, Saudi Arabia.

Settings and Design:

A retrospective cohort study.

Materials and Methods:

Children and young adults (≤40 years) diagnosed with epithelial and mesenchymal bladder neoplasms from 1994 to 2017.

Statistical Analysis Used:

Descriptive data are presented as mean (standard deviation) or median (interquartile range) for continuous variables and n (%) for categorical variables. Statistical Package for Social Sciences version 23 was used.

Results:

Thirty-eight cases were identified. The majority, 71.1% (n = 27) were male. The median age of diagnosis was 33 years ranging from 1 to 40 years. Nearly 45% (n = 17) were smokers. Macroscopic hematuria was present in 57.8% (n = 22). The most common histopathology was papillary urothelial carcinoma (n = 18, 58%). All mesenchymal neoplasms accounted for 18.4% (n = 7). Of all malignancies, 63.2% (n = 24) and 44.7% (n = 17) were low stage and low grade, respectively. Transurethral resection of bladder tumor (TURBT) was conducted for 81.6% (n = 31). The mean length of follow-up was 36.05 months (±39.4 months). Recurrence occurred in 15.8% (n = 6) and 7.9% (n = 3) had progression. Distant metastasis was reported in 5.3% (n = 2). Nearly 8% (n = 3) died during their follow-up.

Conclusions:

Bladder malignancies at the early fourth decade of life tend to be a low stage and low grade. The most common histopathology was papillary urothelial carcinoma. Management should be based on the clinical and histopathological features. However, most of the patient underwent TURBT.

Prolonged circulation and increased tumor accumulation of liposomal vincristine in a mouse model of rhabdomyosarcoma

AIM

Our goal was to improve vincristine (VCR) based rhabdomyosarcoma (RMS) therapy by encapsulating the drug into liposomes. A targeting strategy was attempted to enhance tumor accumulation.

MATERIALS & METHODS

VCR was loaded in control and peptide-decorated liposomes via an active method. The interaction of an RMS-specific peptide with the presumed target furin and the cellular uptake of both liposomal groups were studied in vitro. Pharmacokinetics and biodistribution of VCR-containing liposomes were assessed in an RMS xenograft mouse model.

RESULTS

Liposomes ensured high VCR concentration in plasma and in the tumor. Peptide-decorated liposomes showed modest uptake in RMS cells.

CONCLUSION

The investigated peptide-modified liposomal formulation may not be optimal for furin-mediated RMS targeting. Nevertheless, VCR-loaded liposomes could serve as a delivery platform for experimental RMS.

CYP2B6rs2279343 Is Associated with Improved Survival of Pediatric Rhabdomyosarcoma Treated with Cyclophosphamide

Background

Rhabdomyosarcoma (RMS) is a small round blue cell malignant tumor, representing 7% of childhood malignancies, and over 50% of all soft tissue sarcomas. Cyclophosphamide (CPA) is a prodrug and is the mainstay of RMS treatment. CYP2B6 is a highly polymorphic drug metabolizing enzyme involved in CPA bioactivation. The influence of CYP2B6 single nucleotide polymorphisms (SNPs) on the survival of RMS is still unknown.

Methods

We genotyped CYP2B6SNPs rs2279343, rs3745274, and rs3211371 by restriction fragment polymorphism (RFLP) after PCR amplification in a cohort of 73 pediatric RMS patients treated with CPA-based first line treatment. We then analyzed the association between those genotypes and survival outcome of RMS.

Results

The frequencies of CYP2B6 rs2279343, rs3745274, and rs3211371 were 63%, 45.2%, and 5.5%, respectively. There was no association between rs3745274, rs3211371 genotypes and survival outcomes of RMS. However, the carriers of at least one mutant allele CYP2B6rs2279343 had significantly longer event-free survival (p-value = 0.03).

Conclusion

Our results demonstrated that CYP2B6 rs2279343 may predict EFS in RMS patients and warrants future studies to clarify the pharmacogenetics of CPA in pediatrics. If validated, integration of genetic factors with clinical and molecular characteristics could be used for a composite algorithm to better stratify risk prior to treatment.

Histone Deacetylase Inhibitors Inhibit Rhabdomyosarcoma by Reactive Oxygen Species-Dependent Targeting of Specificity Protein Transcription Factors

The two major types of rhabdomyosarcoma (RMS) are predominantly diagnosed in children, namely embryonal (ERMS) and alveolar (ARMS) RMS, and patients are treated with cytotoxic drugs, which results in multiple toxic side effects later in life. Therefore, development of innovative chemotherapeutic strategies is imperative, and a recent genomic analysis suggested the potential efficacy of reactive oxygen species (ROS)-inducing agents. Here, we demonstrate the efficacy of the potent histone deacetylase (HDAC) inhibitors, panobinostat and vorinostat, as agents that inhibit RMS tumor growth in vivo, induce apoptosis, and inhibit invasion of RD and Rh30 RMS cell lines. These effects are due to epigenetic repression of cMyc, which leads to decreased expression of cMyc-regulated miRs-17, -20a, and -27a; upregulation of ZBTB4, ZBTB10, and ZBTB34; and subsequent downregulation of Sp transcription factors. We also show that inhibition of RMS cell growth, survival and invasion, and repression of Sp transcription factors by the HDAC inhibitors are independent of histone acetylation but reversible after cotreatment with the antioxidant glutathione. These results show a novel ROS-dependent mechanism of antineoplastic activity for panobinostat and vorinostat that lies outside of their canonical HDAC-inhibitory activity and demonstrates the potential clinical utility for treating RMS patients with ROS-inducing agents.

Clinicopathological characteristics and treatment outcomes of Chinese patients with genitourinary embryonal rhabdomyosarcoma

Background

Genitourinary embryonal rhabdomyosarcoma is rarely reported in China. This retrospective analysis aimed to characterize the clinicopathologic features and treatment outcomes of genitourinary embryonal rhabdomyosarcoma in a sample of Chinese patients.

Methods

Basic demographic and clinical data of 29 patients, who were diagnosed with genitourinary embryonal rhabdomyosarcoma between January 2000 and December 2011, were retrieved and analyzed.

Results

In these patients, 25 were males and 4 were females with a median age of 12 years. Paratesticule was the most common lesion site, followed by the prostate, bladder, and vagina. The median tumor size was 5.80 cm. Six patients had clinically positive regional nodes. At the initial diagnosis, patients had a metastatic disease. According to the TNM staging classification for the IRS-IV, phase I lesions were detected in ten cases, phase II lesions in six cases, phase III lesions in four cases, and phase IV lesions in nine cases. The median survival of all patients was 63 (range from 6 to 118) months. The 1-, 3-, and 5-year survival rates for these patients were 93%, 83%, and 52%, respectively. Multivariate analyses demonstrated that staging and anemia were significant predictors of prognosis.

Conclusions

Our findings suggest that metastasis predicts a poor prognosis. Chemotherapy played an important role in comprehensive treatment. Palliative and neo-adjuvant chemotherapy could increase median survival time.

The novel tubulin polymerization inhibitor MHPT exhibits selective anti-tumor activity against rhabdomyosarcoma in vitro and in vivo

The dose-limiting toxicity caused by standard chemotherapy has become a major roadblock to successful rhabdomyosarcoma chemotherapy. By screening a thiazolidinone library including 372 compounds, a novel synthetic compound, 2-((4-hydroxyphenyl)imino)-5-(3-methoxybenzylidene)thiazolidin-4-one (MHPT), was identified as a potent and selective anti-rhabdomyosarcoma agent. MHPT inhibited 50% of the growth of the rhabdomyosarcoma cell lines RD and SJ-RH30 at 0.44 μM and 1.35 μM, respectively, while displaying no obvious toxicity against normal human fibroblast cells at 100 μM. Further investigation revealed that MHPT suppressed the polymerization of tubulin, leading to rhabdomyosarcoma cell growth arrest at the G2/M phase followed by apoptosis. In vivo, MHPT inhibited tumor growth by 48.6% relative to the vehicle control after 5 intraperitoneal injections of 40 mg/kg without appreciable toxicity to normal tissues and systems in an RD xenograft mouse model, while vincristine caused lethal toxicity when similar growth inhibition was achieved. As a moderate tubulin polymerization inhibitor compared with vincristine, MHPT requires a more dynamic tubulin to exert its cytotoxicity, which is a situation that only exists in cancer cells. This attribute may account for the low toxicity of MHPT in normal cells. Our data suggest that MHPT has the potential to be further developed into a selective anti-rhabdomyosarcoma drug with low toxicity.

Rhabdomyosarcoma of the head and neck in children

Rhabdomyosarcoma (RMS) is the most frequent soft tissue sarcoma in children. It is localized in the head and neck region in 40% of cases. Treatment of RMS is complex, including multi-drug chemotherapy, radiotherapy and surgery. The progress that has been accomplished in oncology in recent decades significantly improved outcomes. The 5-year survival rate raised from 25% in 1970 to 73% in 2001, according to IRS-IV data. The outcome is influenced by primary tumor localization, clinical staging, histological tumor type and age at the moment of diagnosis. The relatively rare incidence of these tumors resulted in difficulties in creating more standardized therapeutic protocols. Comparison of outcomes in large patients groups led to an increase in the number of patients with complete remission. Although survival rates of RMS patients have improved, searching for new therapeutic modalities and substances is still essential to improve outcomes in cases of more advanced stages and unfavorable tumor localizations.

Tailor-made treatment combined with proton beam therapy for children with genitourinary/pelvic rhabdomyosarcoma

BACKGROUND

Rhabdomyosarcoma (RMS) is one of the most common soft tissue sarcomas among children. Patients who developed genitourinary/pelvic rhabdomyosarcoma (GU/P-RMS) have a higher complication ratio and relatively poorer event free survival, with local therapy being very important. While proton beam therapy (PBT) is expected to reduce co-morbidity, especially for children, this lacks firm evidence and analysis. We analyzed GU/P-RMS children who had undergone multimodal therapy combined with PBT at a single institution.

METHOD

We retrospectively reviewed charts of children with GU/P-RMS treated from January 2007 to May 2013 at the University of Tsukuba Hospital who had undergone multimodal therapy with PBT.

RESULTS

There were 5 children and their median age at diagnosis was 2.8 years (0.6-4.4 years). Primary sites were the bladder (2) and the prostate (3). All received neo-adjuvant chemotherapy and 3 underwent chemotherapy during PBT (Group Cx). All patients of Group Cx developed leukocytopenia (WBC <1000/μL). The median dose of PBT was 47.7 GyE (41.4-50.4 GyE). All patients survived by their last hospital visit (median, 36 months).

CONCLUSIONS

We analyzed multimodal treatment combined with PBT applied for GU/P-RMS. PBT was well tolerated and could be a plausible choice instead of photon therapy for this population.

Overexpression of the skNAC gene in human rhabdomyosarcoma cells enhances their differentiation potential and inhibits tumor cell growth and spreading

Skeletal and heart muscle-specific variant of the alpha subunit of nascent polypeptide complex (skNAC) is exclusively present in striated muscle cells. During skeletal muscle cell differentiation, skNAC expression is strongly induced, suggesting that the protein might be a regulator of the differentiation process. Rhabdomyosarcoma is a tumor of skeletal muscle origin. Since there is a strong inverse correlation between rhabdomyosarcoma cell differentiation status and metastatic potential, we analyzed skNAC expression patterns in a set of rhabdomyosarcoma cell lines: Whereas RD/12 and RD/18 cells showed a marked induction of skNAC gene expression upon the induction of differentiation-similarly as the one seen in nontransformed myoblasts-skNAC was not induced in CCA or Rh30 cells. Overexpressing skNAC in CCA and Rh30 cells led to a reduction in cell cycle progression and cell proliferation accompanied by an upregulation of specific myogenic differentiation markers, such as Myogenin or Myosin Heavy Chain. Furthermore, in contrast to vector-transfected controls, a high percentage of the cells formed long, Myosin Heavy Chain-positive, multinucleate myotubes. Consistently, soft agar assays revealed a drop in the metastatic potential of skNAC-overexpressing cells. Taken together, these data indicate that reconstitution of skNAC expression can enhance the differentiation potential of rhabdomyosarcoma cells and reduces their metastatic potential, a finding which might have important therapeutic implications.

RAGE signaling deficiency in rhabdomyosarcoma cells causes upregulation of PAX7 and uncontrolled proliferation

Embryonal rhabdomyosarcomas (ERMSs) show elevated levels of PAX7, a transcription factor that marks quiescent adult muscle stem (satellite) cells and is important for proliferation and survival of activated satellite cells and whose timely repression is required for myogenic differentiation. However, the mechanism of PAX7 accumulation in ERMSs and whether high PAX7 causes uncontrolled proliferation in ERMS remains to be elucidated. The receptor for advanced glycation end-products (RAGE, encoded by AGER) transduces a myogenic and anti-proliferative signal in myoblasts, and stable transfection of the ERMS cell line TE671, which does not express RAGE, with AGER results in reduced proliferation and formation of tumor masses in vivo, and enhanced apoptosis and myogenic differentiation. Herein, we show that RAGE expression is low or absent in human ERMSs. We also show that in ERMS cells (1) PAX7 accumulates owing to absent or low RAGE signaling; (2) elevated PAX7 levels reduce RAGE expression and levels of MyoD and myogenin, muscle-specific transcription factors required for myoblast proliferation arrest and differentiation, respectively; (3) PAX7 supports myoblast proliferation by reducing the levels of MyoD, primarily by promoting its degradation; and (4), when ectopically expressed in ERMS cells, that RAGE upregulates myogenin which upregulates MyoD and downregulates PAX7, with consequent inhibition of proliferation and stimulation of differentiation. Thus, failure to express RAGE and, hence, MyoD and myogenin above a critical level in ERMS cells might result in deregulated PAX7 expression leading to uncontrolled proliferation and, potentially, to rhabdomyosarcomagenesis.

Sequestration of AS-DACA into acidic compartments of the membrane trafficking system as a mechanism of drug resistance in rhabdomyosarcoma

The accumulation of weakly basic drugs into acidic organelles has recently been described as a contributor to resistance in childhood cancer rhabdomyosarcoma (RMS) cell lines with differential sensitivity to a novel topoisomerase II inhibitor, AS-DACA. The current study aims to explore the contribution of the endocytic pathway to AS-DACA sequestration in RMS cell lines. A 24-fold differential in AS-DACA cytotoxicity was detected between the RMS lines RD and Rh30. The effect of inhibitors of the endocytic pathway on AS-DACA sensitivity in RMS cell lines, coupled with the variations of endosomal marker expression, indicated the late endosomal/lysosomal compartment was implicated by confounding lines of evidence. Higher expression levels of Lysosomal-Associated Membrane Protein-1 (LAMP1) in the resistant RMS cell line, RD, provided correlations between the increased amount and activity of these compartments to AS-DACA resistance. The late endosomal inhibitor 3-methyladenine increased AS-DACA sensitivity solely in RD leading to the reduction of AS-DACA in membrane trafficking organelles. Acidification inhibitors did not produce an increase in AS-DACA sensitivity nor reduce its sequestration, indicating that the pH partitioning of weakly basic drugs into acidic compartments does not likely contribute to the AS-DACA sequestering resistance mechanism evident in RMS cells.

Primary undifferentiated spindle-cell sarcoma of sella turcica: successful treatment with adjuvant temozolomide

Sellar tumours in adults are most commonly pituitary adenomas. Primary spindle cell sarcoma of the sella turcica without a prior history of cranial radiation is extremely rare. We report a case of a large sellar mass with suprasellar and cavernous sinus extension in a geriatric male patient who presented with complete left oculomotor nerve palsy and panhypopituitarism. The patient underwent partial resection of the sellar mass through transcranial route. The pathology of the mass revealed a poorly differentiated spindle cell neoplasm most consistent with a sarcoma. Postoperatively, the size of the residual sellar mass decreased significantly following six cycles of external beam radiation in conjunction with temozolomide.

The histone methyltransferase SUV39H1 suppresses embryonal rhabdomyosarcoma formation in zebrafish

Epigenetics, or the reversible and heritable marks of gene regulation not including DNA sequence, encompasses chromatin modifications on both the DNA and histones and is as important as the DNA sequence itself. Chromatin-modifying factors are playing an increasingly important role in tumorigenesis, particularly among pediatric rhabdomyosarcomas (RMS), revealing potential novel therapeutic targets. We performed an overexpression screen of chromatin-modifying factors in a KRAS(G12D)-driven zebrafish model for RMS. Here, we describe the identification of a histone H3 lysine 9 histone methyltransferase, SUV39H1, as a suppressor of embryonal RMS formation in zebrafish. This suppression is specific to the histone methyltransferase activity of SUV39H1, as point mutations in the SET domain lacked the effect. SUV39H1-overexpressing and control tumors have a similar proliferation rate, muscle differentiation state, and tumor growth rate. Strikingly, SUV39H1-overexpressing fish initiate fewer tumors, which results in the observed suppressive phenotype. We demonstrate that the delayed tumor onset occurs between 5 and 7 days post fertilization. Gene expression profiling at these stages revealed that in the context of KRAS(G12D) overexpression, SUV39H1 may suppress cell cycle progression. Our studies provide evidence for the role of SUV39H1 as a tumor suppressor.

Rhabdomyosarcoma in adrenal region of a child with hypertension and fever: a case report and literature review

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children but rarely involves the adrenal. We describe a case of alveolar rhabdomyosarcoma (ARMS) of the right adrenal in a 5-year-old boy with a characteristic history of hypertension and recurrent fever. On surveillance imaging, a right adrenal mass was incidentally detected, and a right adrenalectomy was subsequently performed. After the surgery, the fever disappeared simultaneously, and the blood pressure gradually returned to normal level. This is the first reported case in children.

Clinical results of high-dose chemotherapy followed by autologous peripheral blood stem cell transplantation in children with advanced stage rhabdomyosarcoma

Regardless of improvement in cure of Rhabdomyosarcoma (RMS), the results in treatment of advanced stage of RMS in children are still dismal. Recently, high-dose chemotherapy followed by autologous peripheral blood stem cell transplantation (HDC/APBSCT) has been tried to manage the advanced high-risk RMS patients. We investigated the effectiveness of HDC/APBSCT by reviewing the clinical records of high-risk pediatric RMS patients in single institute database. Over twenty years, 37 patients were diagnosed as RMS with high-risk at the time of first diagnosis. These patients were classified as two groups according to treatment method. The first group was HDC/APBSCT and the other was conventional multi-agent chemotherapy group. Differences of clinical results between the two groups were analyzed. The median age of patients was 5 yr, ranging from 6 months to 15 yr. The 5-yr event free survival rate (EFS) of all patients was 24.8% ± 4.8%. HDC/APBSCT group and conventional multi-agent chemotherapy group were 41.3% ± 17.8% and 16.7% ± 7.6% for 5-yr EFS, respectively (P = 0.023). There was a significant difference in the result of HDC/APBSCT between complete remission or very good partial response group and poor response group (50% ± 20.4% vs 37.5% ± 28.6%, P = 0.018). HDC/APBSCT can be a promising treatment modality in high-risk RMS patients.

Comparison of dose intensity of vincristine, d-actinomycin, and cyclophosphamide chemotherapy for child and adult rhabdomyosarcoma: a retrospective analysis

PURPOSE

The prognosis of adult rhabdomyosarcoma (RMS) has been considered dismal. The question is raised that vincristine, d-actinomycin, and cyclophosphamide (VAC) chemotherapy may not be administered as per schedule for adult RMS; consequently, low dose intensity (DI) leads to poor prognosis. Herein, we examined whether the administration of VAC chemotherapy for adults and children with RMS is feasible with regard to the DIs of VAC.

METHODS

Chart review was retrospectively performed for all identified patients. The percentage of relative DI (RDI) was calculated according to the Children's Oncology Group D9803 protocol. Further, we examined the RDI in the first 6 cycles of VAC (induction phase) and the DI after the first 6 cycles of VAC (maintenance phase).

RESULTS

We identified a total of 27 adults and 18 children with RMS, respectively. The mean RDIs of vincristine in total phase were significantly lower in adults than that in children (P = 0.04). In induction phase, the mean RDIs of vincristine and cyclophosphamide were similar for both groups; however, they were dropped significantly in adults during maintenance phase (P < 0.05). Mean RDIs of vincristine in elderly patients tended to become low. Low RDI was mainly attributable to hematologic toxicity, infection, and peripheral neuropathy. The prognosis of low versus high RDI was similar.

CONCLUSIONS

The RDIs of vincristine and cyclophosphamide in the maintenance phase were significantly lower than that in children. VAC chemotherapy for adults was not feasible; these patients require a different regimen.

Retinoic acid fails to induce cell cycle arrest with myogenic differentiation in rhabdomyosarcoma

BACKGROUND

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children. Current treatment strategies do not cure most children with recurrent or high-risk disease, underlying the need for novel therapeutic approaches. Retinoic acid has been shown to induce differentiation in a variety of cells including skeletal myoblasts and neuroblasts. In the setting of minimal residual disease, retinoic acid improves survival in neuroblastoma, another poorly differentiated childhood tumor. Whether such an approach is useful for rhabdomyosarcoma has not yet been investigated. Several in vitro studies have demonstrated an appreciable effect of retinoic acid on human RMS cellular proliferation and differentiation.

PROCEDURE

We assessed the efficacy of ATRA on rhabdomyosarcoma, in vitro and in vivo, using cell lines and xenografts.

RESULTS

ATRA slowed RMS cell proliferation, and promoted a more differentiated myogenic phenotype in both alveolar and embryonal RMS cell lines. Treatment of cultured murine myoblasts with retinoids increased Myogenin expression, but did not induce cell cycle arrest. Despite the favorable in vitro effects, ATRA failed to delay relapse of minimal residual disease using human RMS xenografts in immuno-suppressed NOD-SCID (NSG) mice. Interestingly, tumors that recurred after ATRA treatment showed evidence of enhanced muscle differentiation.

CONCLUSION

Our results indicate that ATRA could increase the expression of some genes associated with muscle differentiation in rhabdomyosarcoma cells, but there was no benefit of single-agent therapy in an MRD model, likely because cell cycle arrest was uncoupled from the pro-differentiation effects of retinoids.

Long-term results in childhood rhabdomyosarcoma: a report from the Italian Cooperative Study RMS 79

BACKGROUND

The results obtained by protocols for children with rhabdomyosarcoma (RMS) have improved in recent decades. Survival curves usually reach a plateau 3 years after the diagnosis, suggesting that long-term survival can be expected, but late events are known to occur. We analyzed the long-term results of the RMS 79 protocol to investigate the type and impact of such events.

PROCEDURE

From 1979 to 1987, 163 children with RMS diagnosed at 21 Italian institutions were registered. Each institution was contacted every year to record patients' status after the end of treatment. When patients were lost to follow-up, their status was checked by inquiring at the Registry Offices of the towns of residence and the cause of death or occurrence of second cancers was investigated by contacting the patients or their family by phone.

RESULTS

Overall, 16 patients had late events, that is, 7 tumor recurrences, 6 second tumors, and 3 deaths due to treatment-related complications. The overall survival rates dropped from 62.6 at 3 years to 52.8 at 20 years. By multivariate analysis, the characteristics influencing long-term survival were histology, tumor site and size, and IRS group. Factors predictive of any kind of late event were tumor site and IRS group.

CONCLUSIONS

Major late events can significantly affect the long-term survival of children with RMS. Modern protocols should provide for a much longer follow-up than is usually considered to confirm the results achieved and enable possible correlations between primary treatment and late events to be investigated.

The effect of the NF-kappa B inhibitors curcumin and lactacystin on myogenic differentiation of rhabdomyosarcoma cells

Rhabdomyosarcoma is a soft tissue sarcoma mainly seen in children. Despite considerable progress within the last few years, therapeutic approaches for this type of tumor are still limited. The respective tumor cells originate from myogenic precursor cells and are characterized by a blockade in their differentiation program. Interestingly, there is a direct inverse correlation between the differentiation status of a specific rhabdomyosarcoma cell and its metastatic potential. Thus, here, we tested whether the ubiquitous transcription factor NF-κB, which regulates myogenic differentiation and is also a promising therapeutic target in the treatment of other types of tumors, might be an interesting candidate for the development of novel rhabdomyosarcoma treatment strategies. For this purpose, we analyzed NF-κB activity (classical pathway) in myoblasts with different differentiation potential, specifically in three different rhabdomyosarcoma cell lines. In addition, we inhibited NF-κB activity in these cells and analyzed the effects on myogenic differentiation. We show that after the induction of differentiation, NF-κB activity declines rapidly in normal myoblasts, but only slightly in rhabdomyosarcoma cells. However, after treatment of the cells with two different small-molecule NF-κB-inhibiting compounds, the IKK inhibitor curcumin and the proteasome inhibitor lactacystin, we found that neither curcumin nor lactacystin promoted myogenic differentiation in either normal myoblasts or rhabdomyosarcoma cells. Taken together, our data suggest that treatment with curcumin or lactacystin might not be a suitable approach in the treatment of rhabdomyosarcoma.

Clinical outcomes of adult and childhood rhabdomyosarcoma treated with vincristine, d-actinomycin, and cyclophosphamide chemotherapy

BACKGROUND

Outcomes in adult patients with rhabdomyosarcoma are poor, with a 5-year survival rate of approximately 30 %. The current study aimed to compare the clinical outcomes of adult and childhood rhabdomyosarcoma patients with local and metastatic disease and to examine the impact and timing of local therapy on metastasis.

METHODS

Clinicopathological features and patient outcomes were reviewed retrospectively for rhabdomyosarcoma patients receiving chemotherapy between 1981 and 2010 at our institution. Adults were defined as those aged 21 years or older.

RESULTS

Of the 98 patients identified, 36 were adults (median age, 29; range, 21-72) and 62 were children (median age, 11; range, 0.6-20). Median progression-free survival of localized and metastatic disease for children and adults was as follows: localized disease, 166.9 versus 22.4 months (p = 0.005), and metastatic disease, 13.3 versus 13.3 months (p = 0.949), respectively. Multivariate regression analysis revealed that older age (≥ 21 vs. <21) was a significant poor prognostic factor in localized disease. Conversely, age was not related to survival in metastatic disease. Receiving radiotherapy to the primary site was an independent factor indicating a better prognosis. An analysis of the optimal timing of local therapy was performed for 53 patients; however, its significance on survival could not be determined.

CONCLUSIONS

Age was a negative prognostic factor in rhabdomyosarcoma patients with localized disease, but it did not affect the survival in metastatic disease. For metastatic disease, although local therapies may be effective for survival, the timing of such therapies should be determined individually.

The over-expression of cell migratory genes in alveolar rhabdomyosarcoma could contribute to metastatic spread

Alveolar (ARMS) and Embryonal (ERMS) rhabdomyosarcoma differ in their response to current treatments. The ARMS subtype has a less favourable prognosis and often presents with widespread metastases, while the less metastatic ERMS has a 5 year survival rate of more than 80 %. In this study we investigate gene expression differences that could contribute to the high frequency of metastasis in ARMS. Microarray analysis identified significant differences in DNA repair, cell cycle and cell migration between the two RMS subtypes. Two genes up regulated in ARMS and involved in cell migration; the engulfment and cell motility gene 1 (ELMO1) and NEL-like 1 gene (NELL1) were selected for further investigation. Over-expression of ELMO1 significantly increased cell invasion from 24.70 ± 7% to 93 ± 5.4% in primary myoblasts and from 29.43 ± 2.1% to 87.33 ± 4.1% in the ERMS cell line RD. siRNA knockout of ELMO1 in the ARMS cell line RH30 significantly reduced cell invasion from 88.2 ± 3.8% to 35.2 ± 2.5%. Over-expression of NELL1 significantly increased myoblast invasion from 23.6 ± 6.9% to 100 ± 0.1%, but had no effect on invasion of the ERMS cell line RD. These findings suggest that ELMO1 may play a key role in ARMS metastasis. NELL1 increased invasion in primary myoblasts, but other factors required for it to enhance motility were not present in the RD ERMS cell line. Impairing ELMO1 function by pharmacological or siRNA knockdown could be a highly effective approach to reduce the metastatic spread of RMS.

The role of neoadjuvant chemotherapy in children with malignant solid tumors

Pediatric surgeons play a critical role in diagnosing, staging, and treating malignant solid tumors in children. Over the years, the surgical management of the primary tumor site has evolved from an aggressive en-bloc resection at diagnosis to a more tailored surgical approach, often affecting definitive local control after the delivery of neoadjuvant therapy, as currently directed by many solid tumor protocols. In fact, inappropriate upfront resection can lead to unnecessary short- and long-term morbidity, an incomplete resection, and may be associated with a delay in the initiation of the systemic chemotherapy that is critical to the treatment of gross or occult metastatic disease. Therefore, it is important for the pediatric surgeon, as a member of the multidisciplinary team involved in the care of these children, to understand the indications for and implications of neoadjuvant therapy in the treatment of pediatric solid tumors. Here we review the current management of childhood solid tumors focusing on the role of neoadjuvant therapy.

Urogenital tumours in childhood

The commonest urogenital tumours in childhood are Wilms tumour of the kidney and rhabdomyosarcoma in the pelvis. We review these tumours along with other primary renal tumours and less common ovarian and testicular tumours in childhood. Current clinical concepts, relevant staging investigations and imaging features are described.

Undifferentiated sarcoma of the sellar region

Malignancies lacking specific features of cellular maturation are termed "undifferentiated" and represent 5-10% of all human tumors. They are encountered at a variety of sites but do not, as a rule, arise in the sellar region. A 39-year-old male with a history of testicular seminoma and an unsuccessful biopsy of a third ventricular neoplasm, presented with visual disturbances and memory loss. Light microscopically, the tumor consisted entirely of undifferentiated spindle cells. No germ cell component was noted. An exhaustive immunohistochemical study found immunoreactivity for vimentin and desmin, but for no other myoid markers. Polymerase chain reaction showed no X;18 translocation. Based upon these studies, a diagnosis of "undifferentiated sarcoma" was made. Our case, being highly unusual among reported sellar neoplasms, underscores the difficulties inherent in the differential diagnosis of undifferentiated neoplasms.

Intracellular trafficking as a determinant of AS-DACA cytotoxicity in rhabdomyosarcoma cells

BACKGROUND

Rhabdomyosarcoma (RMS) is a malignant soft tissue sarcoma derived from skeletal muscle precursor cells, which accounts for 5-8% of all childhood malignancies. Disseminated RMS represents a major clinical obstacle, and the need for better treatment strategies for the clinically aggressive alveolar RMS subtype is particularly apparent. Previously, we have shown that the acridine-4-carboxamide derivative AS-DACA, a known topoisomerase II poison, is potently cytotoxic in the alveolar RMS cell line RH30, but is 190-fold less active in the embryonal RMS cell line RD. Here, we investigate the basis for this selectivity, and demonstrate in these RMS lines, and in an AS-DACA- resistant subclone of RH30, that AS-DACA-induced cytotoxicity correlates with the induction of DNA double strand breaks.

RESULTS

We show that inhibition of the multidrug-resistance associated protein (MRP1) has no effect on AS-DACA sensitivity. By exploiting the pH-dependent fluorescence properties of AS-DACA, we have characterized its intracellular distribution, and show that it concentrates in the cell nucleus, as well as in acidic vesicles of the membrane trafficking system. We show that fluorescence microscopy can be used to determine the localization of AS-DACA to the nuclear and cytoplasmic compartments of RMS cells grown as spheroids, penetrance being much greater in RH30 than RD spheroids, and that the vesicular signal leads the way into the spheroid mass. EEA1 and Rab5 proteins, molecular markers expressed on early-endosomal vesicles, are reduced by >50% in the sensitive cell lines.

CONCLUSION

Taking the evidence as a whole, suggests that endosomal vesicle trafficking influences the toxicity of AS-DACA in RMS cells.

Rhabdomyosarcoma in adolescents: a report from the AIEOP Soft Tissue Sarcoma Committee

BACKGROUND

In many types of cancer, the survival rates are reported to be less favorable for adolescents compared with younger children. To investigate whether this is true for adolescents with rhabdomyosarcoma (RMS), the results obtained in patients enrolled in protocols run by the Italian Soft Tissue Sarcoma Committee (STSC) were analyzed.

METHODS

From 1988 through 2005, 643 patients were registered (567 children ages birth-14 years and 76 adolescents ages 15-19 years) and treated in 4 STSC protocols. The number of patients enrolled was compared with the expected number calculated from incidence rates derived from the Italian network of cancer registries.

RESULTS

Only 27% of the expected number of adolescents with RMS were enrolled in the STSC trials. Compared with children, adolescents were found to have a longer interval from initial symptoms to diagnosis (8 weeks vs 4.6 weeks), more alveolar RMS (47.4% vs 32.6%), lymph node infiltration (39.1% vs 23.3%), and metastases at the time of diagnosis (30.7% vs 17.8%). The 2 age groups received similar treatments. The 5-year overall survival (OS) rate was 68.9% in children versus 57.2% in adolescents (P = .006), and the progression-free survival (PFS) rate was 64.3% in children versus 48.1% in adolescents (P = .0237). On multivariate analysis, age, tumor site, lymph node involvement, and metastases were found to be significant prognostic factors for OS and PFS.

CONCLUSIONS

Survival for adolescents with RMS enrolled in STSC protocols appears to be satisfactory. The higher prevalence of unfavorable tumor characteristics noted among adolescents seems to explain their worse outcome compared with children. However, the limited number of adolescents enrolled in STSC studies is worrisome, and cooperation with oncologists who treat adults needs to be improved.

Inhibition of phosphorylated c-Met in rhabdomyosarcoma cell lines by a small molecule inhibitor SU11274

Background

c-Met is a receptor tyrosine kinase (RTK) that is over-expressed in a variety of cancers and involved in cell growth, invasion, metastasis and angiogenesis. In this study, we investigated the role of c-Met in rhabdomyosarcoma (RMS) using its small molecule inhibitor SU11274, which has been hypothesized to be a potential therapeutic target for RMS.

Methods

The expression level of phosphorylated c-Met in RMS cell lines (RD, CW9019 and RH30) and tumor tissues was assessed by phospho-RTK array and immunohistochemistry, respectively. The inhibition effects of SU11274 on RMS cells were studied with regard to intracellular signaling, cell proliferation, cell cycle and cell migration.

Results

A high level of phosphorylated c-Met was detected in 2 alveolar RMS cell lines (CW9019 and RH30) and 14 out of 24 RMS tissue samples, whereas relatively low levels of phospho-c-Met were observed in the embryonic RMS cell line (RD). The small molecule SU11274 could significantly reduce the phosphorylation of c-Met, resulting in inhibition of cell proliferation, G1 phase arrest of cell cycle and blocking of cell migration in CW9019 and RH30 cell lines.

Conclusion

These results might support the role of c-Met in the development and progression of RMS. Furthermore, the inhibitor of c-Met, SU11274, could be an effective targeting therapy reagent for RMS, especially alveolar RMS.

Selecting multimodal therapy for rhabdomyosarcoma

Rhabdomyosarcoma is a typical tumor of childhood, characterized by a high grade of malignancy, local invasiveness and a marked propensity to metastasize, but also a generally good response to chemotherapy and radiotherapy. Multimodal therapy is essential to cure rhabdomyosarcoma patients, but different uses of surgery, radiotherapy and chemotherapy, and their intensity, need to be selected and modulated to different patient risk groups. This article attempts to give an account of the current treatment options, the open and debated issues and the potential novel strategies for the near future.

Glypican-5 stimulates rhabdomyosarcoma cell proliferation by activating Hedgehog signaling

Binding between the Hedgehog ligand and its receptor Patched 1 is stabilized by Glypican-5.

Glypican-5 (GPC5) is one of the six members of the glypican family. It has been previously reported that GPC5 stimulates the proliferation of rhabdomyosarcoma cells. In this study, we show that this stimulatory activity of GPC5 is a result of its ability to promote Hedgehog (Hh) signaling. We have previously shown that GPC3, another member of the glypican family, inhibits Hh signaling by competing with Patched 1 (Ptc1) for Hh binding. Furthermore, we showed that GPC3 binds to Hh through its core protein but not to Ptc1. In this paper, we demonstrate that GPC5 increases the binding of Sonic Hh to Ptc1. We also show that GPC5 binds to both Hh and Ptc1 through its glycosaminoglycan chains and that, unlike GPC3, GPC5 localizes to the primary cilia. Interestingly, we found that the heparan sulfate chains of GPC5 display a significantly higher degree of sulfation than those of GPC3. Based on these results, we propose that GPC5 stimulates Hh signaling by facilitating/stabilizing the interaction between Hh and Ptc1.

Rhabdomyosarcoma in children: a SEER population based study

OBJECTIVE

To examine incidence and outcomes for pediatric rhabdomyosarcoma (RMS).

METHODS

The SEER registry was examined for patients with RMS < 20 y old.

RESULTS

Overall, 1544 patients were identified for an incidence of 0.4414/100,000 per year. Males outnumbered females 3:2. Tumors were classified as embryonal (67%), alveolar (32%), and pleomorphic (1%). Alveolar and pleomorphic RMS were more common in adolescents, whereas embryonal type was more common in younger children (P = 0.0001). Pleomorphic (47%) and alveolar (39%) RMS commonly presented with distant disease, in contrast to embryonal (25%). Most patients had surgical resection (81%) and radiotherapy (63%). Overall, 5- and 10-y survival was 60% and 57%, respectively. Univariate analysis identified higher survival for age < 10 y, local stage, favorable site, embryonal type, <5 cm tumor size, and surgical resection. Multivariate analysis identified non-embryonal type (HR 1.451), non-favorable site (HR 1.570), no surgery (HR 1.726), age ≥ 10 y (HR 1.734), 1973-1978 diagnosis year (HR 1.730), and distant disease (HR 3.456) as independent predictors of mortality.

CONCLUSIONS

Embryonal histology, the most common type of pediatric RMS, presents in young children and has better prognosis than alveolar or pleomorphic types. Patients with embryonal tumors, favorable tumor location, age < 10 y, localized disease, and surgical resection have improved survival.

Hedgehog, meet Patched

Proteoglycan ensures that the Hedgehog protein and its receptor make a connection.