The cerebral cortex and hippocampus are important for the control of cognitive functions and social behaviors, many of which are sexually dimorphic and tightly regulated by gonadal steroid hormones via activation of their respective nuclear receptors. As different levels of sex steroid hormones are present between the sexes during early development and their receptors act as transcription factors to regulate gene expression, we hypothesize that sexually dimorphic gene expression in the developing mouse cortex and hippocampus might result in sex differences in brain structures and neural circuits governing distinct behaviors between the sexes as adults. To test our hypothesis, we used gene expression microarrays to identify 90 candidate genes differentially expressed in the neonatal cortex/hippocampus between male and female mice, including 55 male-biased and 35 female-biased genes. Among these genes, sexually dimorphic expression of eight sex chromosome genes was confirmed by reverse transcription with quantitative PCR (RT-qPCR), including three located on the X chromosome (Xist, Eif2s3x, and Kdm6a), three on the Y chromosome (Ddx3y, Eif2s3y, and Kdm5d), and two in the pseudoautosomal region of the X and Y chromosomes (Erdr1 and Mid1). In addition, five autosomal genes (Cd151, Dab2, Klk8, Meg3, and Prkdc) were also validated for their sexually dimorphic expression in the neonatal mouse cortex/hippocampus. Gene Ontology annotation analysis suggests that many of these sexually dimorphic genes are involved in histone modifications, cell proliferation/death, androgen/estrogen signaling pathways, and synaptic organization, and these biological processes have been implicated in differential neural development, cognitive function, and neurological diseases between the sexes.

During the perinatal period, male mice are exposed to higher levels of testosterone (T) than females, which promotes sexual dimorphism in their brain structures and behaviors. In addition to acting via estrogen receptors after being locally converted into estradiol by aromatase, T also acts directly through androgen receptor (AR) in the brain. Therefore, we hypothesized that AR expression in the developing mouse cortex and hippocampus was sexually dimorphic. To test our hypothesis, we measured and determined AR mRNA and protein levels in mouse cortex/hippocampus collected on the day of birth (PN0) and 7 (PN7), 14 (PN14), and 21 (PN21) days after birth. We demonstrated that, as age advanced, AR mRNA levels increased in the cortex/hippocampus of both sexes but showed no sex difference. Two AR proteins, the full-length (110 kDa) and a smaller isoform (70 kDa), were detected in the developing mouse cortex/hippocampus with an age-dependent increase in protein levels of both AR isoforms at PN21 and a transient masculine increase in expression of the full-length AR protein on PN7. Thus, we conclude that the postnatal age and sex differences in AR protein expression in combination with the sex differences in circulating T may cause sexual differentiation of the mouse cortex/hippocampus.

To further reveal the molecular mechanism underlying sexual differentiation of the mouse cerebral cortex and hippocampus, we reanalyzed our previous microarray study with Gene Ontology (GO) term enrichment and found that the GO term “RNA binding” was over‐represented among the 89 sexually dimorphic candidate genes. Thus, we selected 16 autosomal genes annotated to the term RNA binding and profiled their mRNA expression in the developing male and female mouse cortex/hippocampus. During the first three weeks after birth, sex differences in mRNA levels of Khdrbs2, Nanos2, Rbm48, and Tdrd3 were observed in the mouse cortex/hippocampus. Of these genes, only the female‐biased expression of Rbm48 in neonates was abolished by prenatal exposure to testosterone propionate (TP), while postnatal treatment of TP three weeks after birth increased Rbm48 and Tdrd3 mRNA levels in both sexes. Regardless of sex, the postnatal cortex/hippocampus also showed a marked increase in the content of androgen receptor (Ar) and estrogen receptor β (Esr2), but a decrease in estrogen receptor α (Esr1) and aromatase (Cyp19a1), which might confer the different responses of Rbm48 to prenatal and postnatal TP. Our results suggest that androgen‐regulated, sexually dimorphic Rbm48 expression might present a novel molecular mechanism by which perinatal androgens control development of sexual dimorphism in cortical and hippocampal structure and function.

The first total synthesis of (–)-merrillianin (1), which is a natural sesquiterpene with a tri- fused structure having a cyclopentane ring and five- and seven-membered lactone parts, is demonstrated. This asymmetric total synthesis enabled the absolute stereo structure determination of naturally occurring (–)-1.

The first total synthesis of (–)-merrillianin (1), which is a natural sesquiterpene with a tri- fused structure having a cyclopentane ring and five- and seven-membered lactone parts, is demonstrated. This asymmetric total synthesis enabled the absolute stereo structure determination of naturally occurring (–)-1.

Anaplastic lymphoma kinase (ALK) is a tyrosine kinase that is constitutively activated in some cancers, due to gene alterations such as chromosomal translocation, amplification, or point mutation. It has been recognized as an attractive solid tumor target since the discovery in 2007 of the fusion gene, comprised of portions of the echinoderm microtubule-associated protein-like 4 (EML4) gene and the ALK gene, which is detected in ca. 6.7% of non-small-cell lung cancer (NSCLC) patients. We have identified a lead compound as an ALK inhibitor through kinase panel screening of in-house kinase-oriented library. The lead compound had a unique scaffold but showed a rather broad kinase inhibition profile. Therefore, we examined structure-activity relationship from the viewpoint of the kinase selectivity as well as ALK inhibition potency. Finally, we identified CH5424802 as a clinical candidate having high selectivity over other kinases including c-Met, c-Kit and KDR. CH5424802 has a preferable PK profile and good oral bioavailability in rats and monkeys. CH5424802 showed preferential antitumor activity against cancers with gene alterations of ALK, such as non-small cell lung cancer (NSCLC) cells expressing EML4-ALK fusion both in vitro and in vivo. CH5424802 is currently being investigated in Phase I/II clinical trials for patients with ALK-positive NSCLC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3593. doi:10.1158/1538-7445.AM2011-3593

We investigate if retinoic acid‐related orphan receptor‐α (Rora) is sexually dimorphic in developing mouse cortex and hippocampus. Recent study shows autistic patients express lower Rora mRNA in their cortex and cerebellum than controls do. Rora may cause sexual bias in autism susceptibility because it regulates expression of aromatase that converts testosterone to estrogen. Reduction of Rora may decrease aromatase levels to increase testosterone levels in autistic subjects (Sarachana et al., 2011). We predict male mice express lower Rora in the cortex and hippocampus as compared to females on the day of birth (PN0), 7 days after birth (PN7), 14 days (PN14), and 21 days after birth (PN21). We extracted RNA from cortexes and hippocampi of male and female C57BL/6J mice at PN0, PN7, PN14, and PN21 (n=8 per group). We measured mRNA levels of Rora and β‐actin (Actb) by RT‐qPCR, normalized Ct values of Rora and Actb, and analyzed two‐way ANOVA (sexes vs. ages) with Bonferroni's test for post‐hoc comparisons. Rora levels in the cortex and hippocampus were significantly higher in PN14 and PN21 mice than in PN0 and PN7 mice (p<0.05), but there was no significant difference between the sexes (p=0.183). Thus, Rora levels in the mouse cortex and hippocampus in early development is age‐dependent, but not sexually dimorphic. This research is supported by CSUPERB Faculty‐Student Collaborative Research Seed Grant and CSULB startup fund.