[Astrocytic neoplasms and correlation with mutate p53 and Ki-67 proteins]

A bidirectional effect of Rac1 inhibition-Protects radiation-induced intestinal injury while inhibits tumor

AIMS

To investigate whether Rac1 inhibition can alleviate radiation-induced intestinal injury (RIII), meanwhile exist no protection on tumors.

MATERIALS AND METHODS

Rac1 inhibition was achieved by its specific inhibitor, NSC23766. Mice were pretreated with different intraperitoneal injections, which were normal saline for NS group (N = 9), and 2.5 mg/kg and 5 mg/kg of NSC23766 for Low-Dose group (N = 9) and High-Dose group (N = 9), respectively. After total body irritation (10Gy), small intestinal tissues were collected for Hematoxylin-Eosin (H&E) staining and Terminal-deoxynucleotidyl Transferase Mediated dUTP Nick End Labeling (TUNEL). Intestinal epithelial and tumor cell lines, namely MODE-k and CT-26, were used to further study the role of Rac1 inhibition on radiation damage. Flow cytometry was used to detect changes in reactive oxygen species production, cell cycles and mitochondrial membrane potential, the latter was also checked by fluorescence microscope. Changes of protein-expression associated with apoptosis and cell cycles were detected by Western blotting to explain the possible molecular mechanism.

KEY FINDINGS

Height of intestine villi and depth of crypt were higher (P < 0.01) and apoptosis ratio lower (P < 0.01) in High-Dose group compared with those in NS group. After radiation, Rac1 inhibition pre-treatment improved the vitality (P < 0.01) and reduced the apoptosis (P < 0.01) in MODE-k while yielded opposite results in CT-26, and reduced ROS production of MODE-k (P < 0.01) while had little effect on that of CT-26. Rac1 inhibition differently affected the cell cycles of normal cells and that of tumor cells.

SIGNIFICANCE

Inhibition of Rac1 could alleviate RIII, meanwhile assist the killing effect of radiation on tumor cells.

Immunohistochemical Expression of Ki-67, PCNA and CD34 in Astrocytomas: A Clinicopathological Study

OBJECTIVES

To assess the immunohistochemical expression of Ki-67 and Proliferating Cell Nuclear Antigen (PCNA) as proliferative markers to study proliferative activity and CD34 as an endothelial cell marker in order to study vascular proliferation in astrocytomas in correlation with some clinicopathological parameters (age, gender, site of the tumor, and tumor grade).

METHODS

A retrospective study wherein a total of 51 formalin-fixed paraffin-embedded brain astrocytoma excisional biopsies covering the period of June 2009 to February 2011 were retrieved from the archival materials of the Specialized Surgical Hospital in Medical City in Baghdad, Iraq. The histopathological diagnosis had been revised and all cases were stained by immunohistochemical technique with Ki-67, PCNA, and CD34 tumor markers. Values were considered statistically significant when p<0.05.

RESULTS

Fibrillary astrocytoma (WHO grade II) was found to be the most common type among astrocytic tumors with the peak age incidence of astrocytomas found in the second and fifth decades of life, and a slight male predominance had been identified. There was a significant correlation between the age of the patients and the grade of the tumor, Ki-67 and PCNA labeling indices, and microvessel density (MVD) detected by CD34 (p<0.05). There was a highly significant correlation between Ki-67 and PCNA labeling indices in astrocytomas (p<0.001).

CONCLUSION

A significant correlation was found between Ki-67, PCNA labeling indices, and MVD (microvessel density) detected by CD34, and between the clinicopathological variables of astrocytomas (age and grade of tumor). Hence, Ki-67 and PCNA, as markers for proliferation, and MVD as a marker of angiogenesis, could be used as ancillary methods in the differentiation of borderline grades of astrocytomas.