Deregulated Rac1 Activity in Neural Crest Controls Cell Proliferation, Migration and Differentiation During Midbrain Development

Mutations in RAC1 allele are implicated in multiple brain tumors, indicating a rigorous control of Rac1 activity is required for neural tissue normal development and homeostasis. To understand how elevated Rac1 activity affects neural crest cells (NCCs) development, we have generated Rac1CA;Wnt1-Cre2 mice, in which a constitutively active Rac1G12V mutant is expressed specifically in NCCs derivatives. Our results revealed that augmented Rac1 activity leads to enlarged midbrain and altered cell density, accompanied by increased NCCs proliferation rate and misrouted cell migration. Interestingly, our experimental data also showed that elevated Rac1 activity in NCCs disrupts regionalization of dopaminergic neuron progenitors in the ventral midbrain and impairs their differentiation. These findings shed light on the mechanisms of RAC1 mutation correlated brain tumor at the cellular and molecular level.

Comparative Parameters of Occult and Multiple Brain Tumors In Human: The Implication for Therapy

Background Brain cancer treatment is a difficult task, because of complex nature of physico-chemical properties of brain, central nervous system (cns) acting drugs and drug carriers. Methods In view of this, literatures were searched with a view to assessing comparative mathematical parameters of occult and multiple primary brain tumors and their therapeutic outcomes. A total of thirteen patients comprised of eight males and five females who had suffered either occult or multiple brain tumors were used for the study. Tumor parameters and their therapeutic prognoses were mathematically determined. The data were analyzed using a modified Kaplan-Meier method at 5 % level of significance. Results Findings have shown that occult tumors such as meningiosarcoma (65.4cm3), teratoma (268 cm3), solitary brain tumor (20.6–22.4 cm3) and gliosarcoma (31.1 cm3) as well as multiple primary brain tumors; meningioma/diffuse astrocytoma (47.7 cm3), glioblastoma multiforme/pituitary adenoma (164. 59 cm3) and planum sphenoidale meningioma/pituitary adenoma (26.52 cm3) are deadly. However solitary brain tumor (4.2 cm3), glioblastoma multiforme/pituitary adenoma (12.77 cm3) and multimeningioma/pituitary adenoma (0.70 cm3) have high survival rate. Generally tumor weight (4.2–144.0 g), tumor density (0.24–0.96), total population of tumor cells (9.5 x 108-2.5 x 1011, rate of tumor cell migration (1.10–48.0 cm2/yr) and tumor radius (0.55-4.0 cm) are relatively moderate to very high, signifying that occult brain tumors may generate faster and may be more difficult to treat chemotherapeutically, radiotherapeutically, immunologically and surgically. Brain tumors affect male and female of 2–79 years old. Conclusions The locations of tumors are parietal, temporal, frontal, thalamic, frontoparietal, stellar, and planum sphenoidale lobes. Both occult and multiple brain tumors are diagnosed when all forms of therapy would have been useless.