CSI86

Breast cancer is a heterogeneous cancer, and it has been distinguished into four subtypes: luminal A, luminal B, HER2-positive and basal-like. Molecular mutations, epigenetic alterations, hormone exposure and immune microenvironment are related to the progression of breast cancer.

The following protocol uses the MTT colorimetric assay as a classic literature-established method for assessing cell viability/metabolic activity in cultured mammalian cells. MTT[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] is reduced by metabolically active cells to a colored formazan product; the amount of formazan is quantified spectrophotometrically and provides an indirect measure of metabolically active viable cells. Importantly, MTT reduction reflects cellular oxidoreductase/metabolic activity rather than an absolute direct count of living cells, so changes in cellular metabolism can alter the signal independently of cell number.

Directly induced neuron culture converts somatic cells, most commonly fibroblasts, into induced neurons without passing through a pluripotent or neural progenitor stage; classic evidence shows that mouse fibroblasts can be converted by Ascl1, Brn2/Pou3f2, and Myt1l, human fibroblasts can be converted by defined neuronal transcription factors, and human fibroblasts can also be converted by miR-9/9-124 with neurogenic or subtype-specifying transcription factors. The readout is acquisition of neuronal identity and function, assessed by neuronal morphology, neuronal markers such as Tuj1/βIII-tubulin, MAP2, synapsin, and subtype markers when relevant, together with functional assays such as action-potential firing, synaptic activity, and electrophysiology.