Differential gene expressions of the MAPK signaling pathway in enterovirus 71-infected rhabdomyosarcoma cells

BACKGROUND: Mitogen-activated protein kinase (MAPK) signaling pathway plays an important role in response to viral infection. The aim of this study was to explore the function and mechanism of MAPK signaling pathway in enterovirus 71 (EV71) infection of human rhabdomyosarcoma (RD) cells. METHODS: Apoptosis of RD cells was observed using annexin V-FITC/PI binding assay under a fluorescence microscope. Cellular RNA was extracted and transcribed to cDNA. The expressions of 56 genes of MAPK signaling pathway in EV71-infected RD cells at 8 h and 20 h after infection were analyzed by PCR array. The levels of IL-2, IL-4, IL-10, and TNF-α in the supernatant of RD cells infected with EV71 at different time points were measured by ELISA. RESULTS: The viability of RD cells decreased obviously within 48 h after EV71 infection. Compared with the control group, EV71 infection resulted in the significantly enhanced releases of IL-2, IL-4, IL-10 and TNF-α from infected RD cells (p < 0.05). At 8 h after infection, the expressions of c-Jun, c-Fos, IFN-i, MEKK1, MLK3 and NIK genes in EV71-infected RD cells were up-regulated by 2.08-6.12-fold, whereas other 19 genes (e.g. AKT1, AKT2, E2F1, IKK and NF-κB1) exhibited down-regulation. However, at 20 h after infection, those MAPK signaling molecules including MEKK1, ASK1, MLK2, MLK3, NIK, MEK1, MEK2, MEK4, MEK7, ERK1, JNK1 and JNK2 were up-regulated. In addition, the expressions of AKT2, ELK1, c-Jun, c-Fos, NF-κB p65, PI3K and STAT1 were also increased. CONCLUSION: EV71 infection induces the differential gene expressions of MAPK signaling pathway such as ERK, JNK and PI3K/AKT in RD cells, which may be associated with the secretions of inflammatory cytokines and host cell apoptosis.

Molecular biology and genetics affecting pediatric solid tumors

Since the discovery of oncogenes more than 20 years ago, it has been proven that cancer is a genetically determined disease. Multiple genetic alteration occurs during the course of an illness for neoplasia to develop. Transformation of positive cell growth regulators (oncogenes) and inactivations of negative cell growth regulators (tumor suppressor genes) merge to express a malignant phenotype. These genetic alterations occur as chromosomal translocations, deletions, inversion, amplification or point mutation. The objective of this review is to introduce basic concepts of molecular biology and describe the molecular genetics and biologic clinical findings of the most important solid malignant tumors in children, namely Neuroblastoma, Wilms and Rhabdomyosarcoma. It is the oncology surgeons responsibility to learn basic molecular genetics and tumor biology to provide rational and appropriate care in the setting of multidisciplinary management. Identifications of new oncogenes will continue to be important milestones in diagnosis, early detection of tumor recurrence, and as potential targets for gene therapy. Fusion proteins generated by mutated translocations are true tumor specific antigens and potential targets for therapy. The predicament is that they are proteins needing therapeutic manipulation within the tumor cell nuclei. Technological advances in molecular and genetics will develop tools necessary to manipulate the cell nuclear DNA and target cancer cell

Flow cytometric analysis of DNA ploidy in childhood rhabdomyosarcoma

Flow cytometric DNA analysis was performed on 17 rhabdomyosarcomas in conjunction with a histopathological review to determine the usefulness of this technique to predict the biologic behavior of the tumor and to establish the characteristic ploidy pattern of rhabdomyosarcoma compared to other small round cell tumors occurring in childhood. Aneuploidy including near-tetraploidy is the most common ploidy pattern encountered, followed by multiploidy and diploidy, and the presence of multiploidy in this tumor is useful for differentiating rhabdomyosarcoma from other kinds of small round cell tumors in which there are rare previous reports on occurrence of multiploidy. Even though there is no significant correlation between ploidy pattern and histologic type of rhabdomyosarcoma, patients with multiploid tumors or aneuploid tumors with a DNA index of 1.10-1.80 tend to have a high risk of treatment failure. Therefore, the ploidy pattern seems to be useful for predicting the patient's survival in concert with other variables.