Zhenzhen Chen

Liver cancer has a tendency to develop asymptomatically in patients, so most patients are diagnosed at a later stage. Accumulating evidence implicates that liver tumour-initiating cells (TICs) as being responsible for liver cancer initiation and recurrence. However, the molecular mechanism of liver TIC self-renewal is poorly understood. Here we discover that a long noncoding RNA (lncRNA) termed LncSox4 is highly expressed in hepatocellular carcinoma (HCC) tissues and in liver TICs. We find that LncSox4 is required for liver TIC self-renewal and tumour initiation. LncSox4 interacts with and recruits Stat3 to the Sox4 promoter to initiate the expression of Sox4, which is highly expressed in liver TICs and required for liver TIC self-renewal. The expression level of Sox4 correlates with HCC development, clinical severity and prognosis of patients. Altogether, we find that LncSox4 is highly expressed in liver TICs and is required for their self-renewal.

The first near-infrared fluorescent probe was developed toward Cu(2+). Based on the photo-induced electron transfer (PET) mechanism, the probe exhibited weak fluorescence. Upon the addition of Cu(2+), it fluoresced strongly. The probe offered this unique capability, and was successfully applied to living cells, tissues and in vivo to visualize Cu(2+).

Compared with semiconductor quantum dots and organic chromophores, carbon dots (CDs)-based lysosome probe with strong emission, an intrinsic targeting ability, and easy synthesis procedure were urgently desired in visualization imaging studies. Herein, we showed that it was possible to produce CDs with the desired properties for lysosome imaging via a one-step hydrothermal treatment of commercial reagents, rose bengal (RB) and branched polyethylenimine (bPEI). The prepared bPEI-RB CDs (P-R CDs) had a high fluorescence quantum yield (FLQY) of 90.49%, a narrow emission band of 30 nm, negligible phototoxicity, and dark toxicity. Moreover, P-R CDs had an intrinsic lysosome targeting ability without any postmodification of the ligands. Long-term cell imaging displayed P-R CDs can anchor lysosomes for up to 48 h without leakage. In addition, experimental results confirmed that dehalogenation cross-linking and structural reorganization of the reactants were the main causes of the ultrahigh photoluminescence efficiency, low cytotoxicity, and passivated surface of the P-R CDs. This origin was attributed to the restricted intersystem crossing and nonradiative transition, the reduced production of singlet oxygen, and suitable —NH2 functional groups. Due to outstanding characteristics, P-R CDs may be developed for a promising tool in lysosome images. The concept of facile preparation will also pave a new avenue for developing ultrabright functional nanomaterial markers.

A novel organoselenium fluorescent probe (Rh-Se-2), which features a high signal-to-noise ratio (up to 170-fold), fast response (5 min) and excellent immunity to interferences, was designed, synthesized and applied to bioimaging.