Targeting KRAS in Colorectal Cancer: A Bench to Bedside Review.

Colorectal cancer (CRC) is a heterogeneous disease with a myriad of alterations at the cellular and molecular levels. Kristen rat sarcoma (KRAS) mutations occur in up to 40% of CRCs and serve as both a prognostic and predictive biomarker. Oncogenic mutations in the KRAS protein affect cellular proliferation and survival, leading to tumorigenesis through RAS/MAPK pathways. Until recently, only indirect targeting of the pathway had been investigated. There are now several KRAS allele-specific inhibitors in late-phase clinical trials, and many newer agents and targeting strategies undergoing preclinical and early-phase clinical testing. The adequate treatment of KRAS-mutated CRC will inevitably involve combination therapies due to the existence of robust adaptive resistance mechanisms in these tumors. In this article, we review the most recent understanding and findings related to targeting KRAS mutations in CRC, mechanisms of resistance to KRAS inhibitors, as well as evolving treatment strategies for KRAS-mutated CRC patients.

Hypoxia Induces Early Neurogenesis in Human Fetal Neural Stem Cells by Activating the WNT Pathway.

Fetal neural stem cells (FNSCs) present in the human fetal brain differentiate into cells of neuronal and glial lineages. The developing fetus is exposed to lower oxygen concentrations than adults, and this physiological hypoxia may influence the growth and differentiation of the FNSCs. This study aimed to evaluate the effect of hypoxia on the differentiation potential of human FNSCs isolated from the subventricular zone of aborted fetal brains (n = 5). FNSCs were isolated, expanded, and characterized by Nestin and Sox2 expression using immunocytochemistry and flow cytometry, respectively. These FNSCs were exposed to 20% oxygen (normoxia) and 0.2% oxygen (hypoxia) concentrations for 48 h, and hypoxia exposure (n = 5) was validated. Whole transcriptome analyses (Genespring GX13) of FNSCs exposed to hypoxia (Agilent 4 × 44 K human array slides) highlighted that genes associated with neurogenesis were enriched upon exposure to hypoxia. The pathway analysis of these enriched genes (using Metacore) showed the involvement of the WNT signaling pathway. Microarray analyses were validated using neuronal and glial lineage commitment markers, namely, NEUROG1, NEUROG2, ASCL1, DCX, GFAP, OLIG2, and NKX2.2, using qPCR (n = 9). DCX, ASCL1, NGN1, and GFAP protein expression was analyzed by Western blotting (n = 3). This demonstrated upregulation of the neuronal commitment markers upon hypoxia exposure, while no change was observed in astrocytic and oligodendrocyte lineage commitment markers. Increased expression of downstream targets of the WNT signaling pathway, TCF4 and ID2, by qPCR (n = 9) and increased protein expression of CTNNB1 (ß-catenin) and ID2 by Western blot (n = 3) indicated its involvement in mediating neuronal differentiation upon exposure to hypoxia.

Cytokine and growth factor profile in endometriosis: a multiplex analysis of peritoneal fluid to assess diagnostic utility.

We aimed to assay cytokines and growth factors in peritoneal fluid samples from women with and without endometriosis to understand the inflammatory milieu, and assess their potential diagnostic utility. This cross-sectional study conducted at a tertiary care hospital included 54 women, aged 20-45 years, with regular menstrual history and undergoing diagnostic/therapeutic laparoscopy for infertility and/or pain. Peritoneal fluid samples were collected after insertion of trocar & laparoscope but prior to other surgical intervention. A multiplex immunoassay of 27 cytokines and growth factors was performed. The concentration of FGF2 and CSF3 were significantly lower in women with endometriosis than without endometriosis (p = .043 and .003, respectively). The levels of CCL2 and IL1RN were significantly higher in moderate-severe than in minimal-mild endometriosis (p = .038 and .043, respectively). Phase-specific comparison revealed that in proliferative phase, the levels of CSF2 and CSF3 were lower in women with endometriosis than without the disease (p = .047 and .013, respectively). The ROC curve analysis provided a cutoff value 0.78 and 0.76 for FGF2 and CSF3, respectively. Cytokines and growth factors such as FGF2, CSF3, CSF2, CCL2 and IL1RN seem to contribute to the pathogenesis of endometriosis and may have a potential utility for the diagnosis of endometriosis.

In ovo Sound Stimulation Mediated Regulation of BDNF in the Auditory Cortex and Hippocampus of Neonatal Chicks.

Brain-derived neurotrophic factor (BDNF) is known to mediate activity-dependent changes in the developing auditory system. Its expression in the brainstem auditory nuclei, auditory cortex and hippocampus of neonatal chicks (Gallus gallus domesticus) in response to in ovo high intensity sound exposure at 110 dB (arrhythmic sound: recorded traffic noise, 30-3000 Hz with peak at 2700 Hz, rhythmic sound: sitar music, 100-4000 Hz) was examined to understand the previously reported altered volume and neuronal number in these regions. In the brainstem auditory nuclei, no mature BDNF, but proBDNF at the protein level was detected, and no change in its levels was observed after in ovo sound stimulation (music and noise). Increased ProBDNF protein levels were found in the auditory cortex in response to arrhythmic sound, along with decreased levels of one of the BDNF mRNA transcripts, in response to both rhythmic and arrhythmic sound stimulation. In the hippocampus, increased levels of mature BDNF were found in response to music. Expression microarray analysis was performed to understand changes in gene expression in the hippocampus in response to music and noise, followed by gene ontology analysis showing enrichment of probable signaling pathways. Differentially expressed genes like CAMK1 and STAT1 were found to be involved in downstream signaling on comparing music versus noise-exposed chicks. In conclusion, we report that BDNF is differentially regulated in the auditory cortex at the transcriptional and post-translational level, and in the hippocampus at the post-translational level in response to in ovo sound stimulation.