This study was undertaken to delineate a possible role for tissue transglutaminase (tTG), an enzyme that catalyzes protein cross-linking, in hepatic fibrogenesis. Rats were treated with CCl4 solution and then killed at different stages of liver injury and fibrogenesis. Liver tTG mRNA levels were markedly increased as early as 6 h after the first injection, peaked at 4 days and 1 wk, and remained increased for 8 wk. The enzymatic activity of tTG was increased in livers of rats treated with CCl4, in a fashion that paralleled the Northern blot results. Cell isolation experiments indicated that all hepatic cell types synthesize tTG mRNA. Increased binding to the nuclear factor-kappaB (NF-kappaB) motif of the tTG promoter was found in the nuclear extracts prepared from CCl4-treated samples. These data demonstrate an increase in tTG gene expression during hepatic injury and fibrosis, suggesting a possible role for this enzyme in stabilizing the fibrotic bands during hepatic fibrogenesis. Moreover, increased NF-kappaB binding to the tTG promoter may represent one of the mechanisms by which cell injury induces tTG transcription and thus potentiates the process of fibrogenesis.

One of several postulated roles for tissue transglutaminase (tTG) is the stabilization and assembly of extracellular matrix via peptide cross-linking. We previously determined that tTG activity increased in an animal model of hepatic fibrogenesis and in human liver disease. To further study the role of tTG in liver disease, we initiated investigations into the effect of a proinflammatory mediator, tumor necrosis factor (TNF)-α, on tTG activity in cultured liver cells. Treatment of human Hep G2 cells with 1 ng/ml TNF-α increased [14C]putrescine cross-linking to cellular proteins. An increase in tTG mRNA content was observed 1 h after addition of TNF-α, and levels of tTG mRNA remained elevated after 24 h. Hep G2 cells, transiently transfected with a luciferase reporter containing 1.67 kb of the human tTG promoter, showed an increase in reporter activity after addition of TNF-α. Gel shift experiments using nuclear extracts from TNF-α-treated cells and oligonucleotides containing the tTG nuclear factor (NF)-κB motif revealed increased binding, concordant with mRNA data. Transient transfections with a truncated reporter construct lacking the tTG NF-κB sequence showed an attenuated response to TNF-α treatment. Similar responses were seen in stably transfected HeLa cells. Primary hepatocytes isolated from a trangenic mouse line containing the mouse tTG promoter driving the β-galactosidase reporter, show similar time-dependent increases in promoter activity when treated with TNF-α. Furthermore, Hep G2 cells are incapable of upmodulating tTG promoter reporter activity in the presence of TNF-α when those cells overexpress a transdominant, negative mutant NF-κB subunit. Because TNF-α expression is upregulated in hepatic inflammation, the data suggest TNF-α-mediated increases in tTG expression may play an important role in the process of hepatic fibrogenesis.

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The systemic use of pharmaceutical drugs for cancer patients is a compromise between desirable therapy and side effects because of the intrinsic shortage of organ‐specific pharmaceutical drug. Design and construction of pharmaceutical drug to achieve the organ‐specific delivery is thus desperately desirable. We herein regulate perylene skeleton to effect organ‐specificity and present an example of lung‐specific distribution on the basis of bay‐twisted PDIC‐NC. We further demonstrate that PDIC‐NC can target into mitochondria to act as cellular respiration inhibitor, inducing insufficient production of adenosine triphosphate, promoting endogenous H2O2 and .OH burst, elevating calcium overload, efficiently triggering the synergistic apoptosis, autophagy and endoplasmic reticulum stress of lung cancer cells. The antitumor performance of PDIC‐NC is verified on in vivo xenografted, metastasis and orthotopic lung cancer, presenting overwhelming evidences for potentially clinical application. This study contributes a proof‐of‐concept demonstration of twisted perylene to well attain lung‐specific distribution, and meanwhile achieves intensive lung cancer chemotherapy.