Flavone

By lysing cells, releasing RNA, and removing impurities such as proteins and DNA, high-purity RNA products are finally obtained. The commonly used traditional method is the guanidine isothiocyanate/phenol/chloroform method (Trizol), which is suitable for a variety of animal materials including animal tissues, microorganisms, cultured cells, etc., and most plant materials.

Western blotting (WB) is a commonly used experimental method in molecular biology, biochemistry, and immunogenetics for identifying and quantifying target proteins. It combines gel electrophoresis with immunoassay, enabling researchers to analyze protein expression, post-translational modifications, and molecular weight.

Annexin V-based apoptosis assays rely on the detection of phosphatidylserine (PS) externalization from the inner leaflet of the plasma membrane to the outer leaflet, an early biochemical hallmark of apoptosis. Fluorescently labeled Annexin V binds PS in a calcium-dependent manner, enabling identification of early apoptotic cells by flow cytometry or fluorescence microscopy. When combined with a membrane-impermeant DNA-binding dye (e. g. , propidium iodide), this approach allows discrimination between viable (Annexin V−/dye−), early apoptotic (Annexin V+/dye−), and late apoptotic or necrotic (Annexin V+/dye+) cell populations by assessing membrane integrity and PS exposure.

Bromodeoxyuridine (BrdU) incorporation assay is based on the principle that BrdU, a thymidine analog, is incorporated into newly synthesized DNA during the S phase of the cell cycle, thereby serving as a marker of DNA replication and cellular proliferation. Incorporated BrdU can be detected using anti-BrdU antibodies following DNA denaturation, enabling visualization or quantification of proliferating cells through immunochemical detection methods such as immunofluorescence or immunohistochemistry.

The CFSE (carboxyfluorescein diacetate succinimidyl ester) dye dilution proliferation assay is based on the covalent labeling of intracellular proteins by a cell-permeant fluorescent dye that becomes fluorescent upon intracellular ester cleavage and then is stably retained within cells. As labeled cells divide, the dye is partitioned equally between daughter cells, resulting in a stepwise halving of fluorescence intensity that can be quantified by flow cytometry to determine the number of cell divisions undergone by each cell population. This fluorescence dilution approach enables quantitative tracking of lymphocyte proliferation at the single-cell level over multiple rounds of division. CFSE-based proliferation analysis has been widely applied to measure antigen-driven lymphocyte expansion in vitro, where discrete fluorescence peaks correspond to successive cell divisions and allow reconstruction of proliferative history within heterogeneous populations.

Cell-cycle analysis by flow cytometry measures DNA content in single cells to estimate the fraction of cells in G0/G1, S, and G2/M phases. Propidium iodide intercalates into DNA, and after RNA removal with RNase, fluorescence intensity reflects cellular DNA content: 2N cells are assigned to G0/G1, cells between 2N and 4N to S phase, and 4N cells to G2/M. DNA-content analysis alone cannot reliably separate G0 from G1 or G2 from M. Ki-67 can distinguish quiescent G0 cells from cycling cells, EdU or BrdU incorporation marks active DNA synthesis in S phase, and phospho-histone H3 staining identifies mitotic cells within the 4N population.

Liver cancer can be classified into primary liver cancer and secondary liver cancer. Secondary liver cancer is the metastatic liver cancer. Primary liver cancer includes hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma (ICC) and fibrolamellar HCC, of which HCC is the most common form, accounting for approximately 90% of primary liver cancers^[1]. HCC mouse models include chemical agent-induced models, transplanted tumor models, and genetic engineered models.

Recombinant protein expression in Escherichia coli followed by purification of a His-tagged soluble protein by immobilized metal affinity chromatography (IMAC), with optional MBP fusion and TEV tag removal when the construct includes these elements. The biological readout is production of the encoded target protein, detected as an inducible band at the expected molecular mass by SDS-PAGE and quantified by total protein assay or chromatographic absorbance; the purification readout is enrichment of the target protein in elution fractions after selective binding of polyhistidine residues to immobilized Ni2+/metal-chelate resin and elution by imidazole-containing buffer. Expression is driven by an inducible bacterial expression system, commonly T7/lac-based, in which IPTG or lactose/auto-induction activates transcription and translation of the cloned gene; lower induction temperature, lower inducer concentration, induction timing, and solubility-enhancing fusion tags can influence the frac

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.

Apoptosis, also called programmed cell death, is generally characterized by distinct morphological characteristics.

TUNEL staining detects DNA strand breaks by using terminal deoxynucleotidyl transferase to add labeled nucleotides to exposed 3′-OH DNA termini, generating either microscopic staining in fixed cells or tissue sections, or fluorescence/cytometric signal in cell suspensions. TUNEL positivity reflects DNA fragmentation but should not be interpreted alone as definitive apoptosis, because TUNEL can also label necrotic, autolytic, mechanically damaged, or DNA-repair-associated DNA breaks.

Flow cytometric DNA-content cell-cycle staining measures the fluorescence intensity of DNA-bound fluorochromes in single cells or nuclei to estimate DNA content distributions, allowing assignment of populations to G0/G1, S, and G2/M phases by DNA histogram deconvolution. Propidium iodide (PI) intercalates into DNA, and PI fluorescence is proportional to cellular DNA content when staining is performed under conditions that make DNA accessible and minimize non-DNA signal. Cells with G2/M DNA content are expected to show approximately twice the fluorescence intensity of G0/G1 cells, while S-phase cells occupy intermediate fluorescence values. PI-based DNA-content analysis can also detect cells with fractional DNA content, often reported as sub-G1, when DNA fragmentation and extraction during staining reduce retained DNA signal in apoptotic cells. DAPI is an alternative DNA fluorochrome for univariate DNA-content analysis, while bivariate approaches combining DNA content with proliferation

Apoptosis is a regulated, generally non-lytic cell-death pathway that removes unwanted, damaged, infected, or abnormal cells through coordinated morphological changes, caspase activation, DNA fragmentation, and membrane remodeling. The intrinsic apoptosis pathway is controlled mainly by mitochondrial outer membrane permeabilization, BCL-2 family proteins, cytochrome c release, apoptosome formation, caspase-9 activation, and downstream executioner caspase-3/7 activation. The extrinsic apoptosis pathway is initiated by death receptors such as Fas, TNFR, and TRAIL receptors, which recruit adaptor proteins and activate caspase-8 before engaging executioner caspases or mitochondrial amplification through BID cleavage. Apoptosis is linked to many phenotypes, including cancer cell killing, tissue homeostasis, immune regulation, neurodegeneration, infection response, and treatment-induced cytotoxicity; unresolved questions include how apoptosis interacts with necroptosis, pyroptosis, ferroptos