Analysis of Area-Specific Expression Patterns of RORbeta, ER81 and Nurr1 mRNAs in Rat Neocortex by Double In Situ Hybridization and Cortical Box Method

BACKGROUND: The mammalian neocortex is subdivided into many areas, each of which exhibits distinctive lamina architecture. To investigate such area differences in detail, we chose three genes for comparative analyses, namely, RORbeta, ER81 and Nurr1, mRNAs of which have been reported to be mainly expressed in layers 4, 5 and 6, respectively. To analyze their qualitative and quantitative coexpression profiles in the rat neocortex, we used double in situ hybridization (ISH) histochemistry and cortical box method which we previously developed to integrate the data of different staining and individuals in a standard three-dimensional space. PRINCIPAL FINDINGS: Our new approach resulted in three main observations. First, the three genes showed unique area distribution patterns that are mostly complementary to one another. The patterns revealed by cortical box method matched well with the cytoarchitectonic areas defined by Nissl staining. Second, at single cell level, RORbeta and ER81 mRNAs were coexpressed in a subpopulation of layer 5 neurons, whereas Nurr1 and ER81 mRNAs were not colocalized. Third, principal component analysis showed that the order of hierarchical processing in the cortex correlates well with the expression profiles of these three genes. Based on this analysis, the dysgranular zone (DZ) in the somatosensory area was considered to exhibit a profile of a higher order area, which is consistent with previous proposal. CONCLUSIONS/SIGNIFICANCE: The tight relationship between the expression of the three layer specific genes and functional areas were revealed, demonstrating the usefulness of cortical box method in the study on the cerebral cortex. In particular, it allowed us to perform statistical evaluation and pattern matching, which would become important in interpreting the ever-increasing data of gene expression in the cortex

Patterns of Neurogenesis and Amplitude of Reelin Expression Are Essential for Making a Mammalian-Type Cortex

The mammalian neocortex is characterized as a six-layered laminar structure, in which distinct types of pyramidal neurons are distributed coordinately during embryogenesis. In contrast, no other vertebrate class possesses a brain region that is strictly analogous to the neocortical structure. Although it is widely accepted that the pallium, a dorsal forebrain region, is specified in all vertebrate species, little is known of the differential mechanisms underlying laminated or non-laminated structures in the pallium. Here we show that differences in patterns of neuronal specification and migration provide the pallial architectonic diversity. We compared the neurogenesis in mammalian and avian pallium, focusing on subtype-specific gene expression, and found that the avian pallium generates distinct types of neurons in a spatially restricted manner. Furthermore, expression of Reelin gene is hardly detected in the developing avian pallium, and an experimental increase in Reelin-positive cells in the avian pallium modified radial fiber organization, which resulted in dramatic changes in the morphology of migrating neurons. Our results demonstrate that distinct mechanisms govern the patterns of neuronal specification in mammalian and avian pallial development, and that Reelin-dependent neuronal migration plays a critical role in mammalian type corticogenesis. These lines of evidence shed light on the developmental programs underlying the evolution of the mammalian specific laminated cortex

SOX5 postmitotically regulates migration, postmigratory differentiation, and projections of subplate and deep-layer neocortical neurons

Neocortical projection neurons exhibit layer-specific molecular profiles and axonal connections. Here we show that the molecular identities of early-born subplate and deep-layer neurons are not acquired solely during generation or shortly thereafter but undergo progressive postmitotic refinement mediated by SOX5. Fezf2 and Bcl11b, transiently expressed in all subtypes of newly postmigratory early-born neurons, are subsequently downregulated in layer 6 and subplate neurons, thereby establishing their layer 5-enriched postnatal patterns. In Sox5-null mice, this downregulation is disrupted, and layer 6 and subplate neurons maintain an immature differentiation state, abnormally expressing these genes postnatally. Consistent with this disruption, SOX5 binds and represses a conserved enhancer near Fezf2. The Sox5-null neocortex exhibits failed preplate partition and laminar inversion of early-born neurons, loss of layer 5 subcerebral axons, and misrouting of subplate and layer 6 corticothalamic axons to the hypothalamus. Thus, SOX5 postmitotically regulates the migration, postmigratory differentiation, and subcortical projections of subplate and deep-layer neurons

Sotorasib versus docetaxel for previously treated non-small-cell lung cancer with KRASG12C mutation: a randomised, open-label, phase 3 trial.

Sotorasib is a specific, irreversible inhibitor of the GTPase protein, KRAS <sup>G12C</sup> . We compared the efficacy and safety of sotorasib with a standard-of-care treatment in patients with non-small-cell lung cancer (NSCLC) with the KRAS <sup>G12C</sup> mutation who had been previously treated with other anticancer drugs. We conducted a randomised, open-label phase 3 trial at 148 centres in 22 countries. We recruited patients aged at least 18 years with KRAS <sup>G12C</sup> -mutated advanced NSCLC, who progressed after previous platinum-based chemotherapy and a PD-1 or PD-L1 inhibitor. Key exclusion criteria included new or progressing untreated brain lesions or symptomatic brain lesions, previously identified oncogenic driver mutation other than KRAS <sup>G12C</sup> for which an approved therapy is available (eg EGFR or ALK), previous treatment with docetaxel (neoadjuvant or adjuvant docetaxel was allowed if the tumour did not progress within 6 months after the therapy was terminated), previous treatment with a direct KRAS <sup>G12C</sup> inhibitor, systemic anticancer therapy within 28 days of study day 1, and therapeutic or palliative radiation therapy within 2 weeks of treatment initiation. We randomly assigned (1:1) patients to oral sotorasib (960 mg once daily) or intravenous docetaxel (75 mg/m <sup>2</sup> once every 3 weeks) in an open-label manner using interactive response technology. Randomisation was stratified by number of previous lines of therapy in advanced disease (1 vs 2 vs >2), ethnicity (Asian vs non-Asian), and history of CNS metastases (present or absent). Treatment continued until an independent central confirmation of disease progression, intolerance, initiation of another anticancer therapy, withdrawal of consent, or death, whichever occurred first. The primary endpoint was progression-free survival, which was assessed by a blinded, independent central review in the intention-to-treat population. Safety was assessed in all treated patients. This trial is registered at ClinicalTrials.gov, NCT04303780, and is active but no longer recruiting. Between June 4, 2020, and April 26, 2021, 345 patients were randomly assigned to receive sotorasib (n=171 [50%]) or docetaxel (n=174 [50%]). 169 (99%) patients in the sotorasib group and 151 (87%) in the docetaxel group received at least one dose. After a median follow-up of 17·7 months (IQR 16·4-20·1), the study met its primary endpoint of a statistically significant increase in the progression-free survival for sotorasib, compared with docetaxel (median progression-free survival 5·6 months [95% CI 4·3-7·8] vs 4·5 months [3·0-5·7]; hazard ratio 0·66 [0·51-0·86]; p=0·0017). Sotorasib was well tolerated, with fewer grade 3 or worse (n=56 [33%] vs n=61 [40%]) and serious treatment-related adverse events compared with docetaxel (n=18 [11%] vs n=34 [23%]). For sotorasib, the most common treatment-related adverse events of grade 3 or worse were diarrhoea (n= 20 [12%]), alanine aminotransferase increase (n=13 [8%]), and aspartate aminotransferase increase (n=9 [5%]). For docetaxel, the most common treatment-related adverse events of grade 3 or worse were neutropenia (n=13 [9%]), fatigue (n=9 [6%]), and febrile neutropenia (n=8 [5%]). Sotorasib significantly increased progression-free survival and had a more favourable safety profile, compared with docetaxel, in patients with advanced NSCLC with the KRAS <sup>G12C</sup> mutation and who had been previously treated with other anticancer drugs. Amgen