FAK is a tyrosine kinase overexpressed in cancer cells and plays an important role in the progression of tumors to a malignant phenotype. Except for its typical role as a cytoplasmic kinase downstream of integrin and growth factor receptor signaling, related studies have shown new aspects of the roles of FAK in the nucleus. FAK can promote p53 degradation through ubiquitination, leading to cancer cell growth and proliferation. FAK can also regulate GATA4 and IL-33 expression, resulting in reduced inflammatory responses and immune escape. These findings establish a new model of FAK from the cytoplasm to the nucleus. Activated FAK binds to transcription factors and regulates gene expression. Inactive FAK synergizes with different E3 ligases to promote the turnover of transcription factors by enhancing ubiquitination. In the tumor microenvironment, nuclear FAK can regulate the formation of new blood vessels, affecting the tumor blood supply. This article reviews the roles of nuclear FAK in regulating gene expression. In addition, the use of FAK inhibitors to target nuclear FAK functions will also be emphasized.
Mitophagy is a process in which cells remove dysfunctional mitochondria and recycle their constituents in a lysosome-dependent manner. To probe this process, two different fluorescent dyes specific for mitochondria and lysosomes, respectively, are often used in combination. However, current fluorescent dyes for lysosomes cannot distinguish mitochondria-containing autolysosomes from other lysosomes. Therefore, we herein report a cyanine dye, HQO, which can simultaneously probe mitochondria and autolysosomes in live cells by exhibiting different fluorescence properties. HQO selectively accumulates in mitochondria but then transforms to the protonated HQOH(+) form with the decrease of pH when dysfunctional mitochondria evolve into autolysosomes. Since HQO and HQOH(+) exhibit different absorption and emission with Ex/Em at 530/650 and 710/750 nm, respectively, in a low polarity environment, such as that found in micelles, they are uniquely suited to monitor mitophagy with the ability to distinguish autolysosomes from other lysosomes.
Exploring semiconductor quantum dots (QDs) with circularly polarized luminescence (CPL) is desirable to design optoelectronic devices owing to the easily tunable emission wavelengths and photophysical stability.
A protease-activated ratiometric fluorescent probe based on fluorescence resonance energy transfer between a pH-sensitive fluorescent dye and biocompatible Fe3O4 nanocrystals was constructed. A peptide substrate of MMP-9 served as a linker between the particle quencher and the chromophore that was covalently attached to the antitumor antibody. The optical response of the probe to activated MMP-9 and gastric cell line SGC7901 tumor cells was investigated, followed by in vivo tumor imaging. Based on the ratiometric pH response to the tumor microenvironment, the resulting probe was successfully used to image the pH of subcutaneous tumor xenografts.
Integrating chromophores
into chiral photonic crystals to fabricate
materials that exhibit circularly polarized luminescence (CPL) is
promising as this method allows efficient manipulation of the spontaneous
emission within photonic bandgaps (PBGs). However, tuning the wavelength
of CPL and the dissymmetry factor (g
lum) in a convenient and accurate manner remains a significant challenge.
Here, right-handed, tunable upconverted CPL (UC-CPL) emission was
achieved by integrating multiple emissive, upconverting nanoparticles
into cellulose nanocrystal based chiral photonic films that had tunable
PBGs. Glycerol was used to tune the PBGs of the chiral photonic films,
which yielded tunable UC-CPL emission at 450 and 620 nm with a tailored g
lum. Moreover, humidity responsive UC-CPL at
blue wavelength was obtained from glycerol-composite photonic film,
with a g
lum that ranged from −0.156
to −0.033. It was possible because the PBG and chirality of
photonic composite was responded to the relative humidity. This work
gives valuable insight into tunable and stimuli-responsive CPL photonic
systems.
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