Cinobufagin Is a Selective Anti-Cancer Agent against Tumors with EGFR Amplification and PTEN Deletion.

Glioblastoma multiforme (GBM) is the most common and malignant brain tumor, and almost half of the patients carrying EGFR-driven tumor with PTEN deficiency are resistant to EGFR-targeted therapy. EGFR amplification and/or mutation is reported in various epithelial tumors. This series of studies aimed to identify a potent compound against EGFR-driven tumor. We screened a chemical library containing over 600 individual compounds purified from Traditional Chinese Medicine against GBM cells with EGFR amplification and found that cinobufagin, the major active ingredient of Chansu, inhibited the proliferation of EGFR amplified GBM cells and PTEN deficiency enhanced its anti-proliferation effects. Cinobufagin also strongly inhibited the proliferation of carcinoma cell lines with wild-type or mutant EGFR expression. In contrast, the compound only weakly inhibited the proliferation of cancer cells with low or without EGFR expression. Cinobufagin blocked EGFR phosphorylation and its downstream signaling, which additionally induced apoptosis and cytotoxicity in EGFR amplified cancer cells. In vivo, cinobufagin blocked EGFR signaling, inhibited cell proliferation, and elicited apoptosis, thereby suppressing tumor growth in both subcutaneous and intracranial U87MG-EGFR xenograft mouse models and increasing the median survival of nude mice bearing intracranial U87MG-EGFR tumors. Cinobufagin is a potential therapeutic agent for treating malignant glioma and other human cancers expressing EGFR.

beta-Naphthoflavone protects mice from aristolochic acid-I-induced acute kidney injury in a CYP1A dependent mechanism.

AIM: The role of CYP1A in the protection of aristolochic acid (AA)I-induced nephrotoxicity has been suggested. In the present study we investigated the effects of beta-naphthoflavone (BNF), a non-carcinogen CYP1A inducer, on AAI-induced kidney injury. METHODS: Mice were pretreated with 80 mg/kg BNF by daily intraperitoneal injection (ip) for 3 days followed by a single ip of 10 mg/kg AAI. AAI and its major metabolites in blood, liver and kidney, the expression of CYP1A1 and CYP1A2 in microsomes of liver and kidney, as well as the nephrotoxicity were evaluated. RESULTS: BNF pretreatment prevented AAI-induced renal damage by facilitating the disposal of AAI in liver. BNF pretreatment induced the expression of CYP1A1 in both liver and kidney; but the induction of CYP1A2 was only observed in liver. CONCLUSION: BNF prevents AAI-induced kidney toxicity primarily through CYP1A induction.

Synthesis and antitumor activity of 6- and 2-(1-substituted-thio-4-methylpent-3-enyl)-5,8-dimethoxynaphthalene-1,4-diones.

In an attempt to develop potent and selective antitumor agents, a series of 6- and 2-(1-substituted-thio-4-methylpent-3-enyl)-5,8-dimethoxynaphthalene-1,4-diones were designed and synthesized. The cytotoxicities of these compounds were evaluated in vitro against BEL-7402, HT-29 and SPC-A1 cell lines. The pharmacological results showed that most of the prepared compounds displayed the excellent selective cytotoxicity toward HT-29 cells. From the structure-activity relationships we may conclude that the introduction of a thioether functional group at the 1'-position in the side chain of shikonin is associated with an increase in cytotoxicity.

[Construction of recombinant yellow fever virus 17D containing 2A fragment as a vaccine vector].

The Yellow Fever (YF) vaccine, an attenuated yellow fever 17D (YF-17D) live vaccine, is one of the most effective and safest vaccines in the world and is regarded as one of the best candidates for viral expression vector. We here first reported in China the construction and characterization of the recombinant expression vector of yellow fever 17D which contained the proteinase 2A fragment of foot-and-mouth disease virus (FMDV). Three cDNA fragments representing the full-length YF-17D genome, named 5'-end cDNA (A), 3'-end cDNA (B) and middle cDNA (C), were obtained by reverse transcription polymerase chain reaction (RT-PCR), together with the introduction of SP6 enhancer, necessary restriction sites and overlaps for homologous recombination in yeast. Fragment A and B were then introduced into pRS424 in turn by DNA recombination, followed by transfection of fragment C and the recombinant pRS424 containing A and B (pRS-A-B) into yeast. A recombinant vector containing full length cDNA of YF-17D (pRS-YF) was obtained by screening on medium lack of tryptophan and uracil. A recombinant YF-17D expression vector containing FMDV-2A gene fragment (pRS-YF-2A1) was then constructed by methods of DNA recombination and homologous recombination in yeast described above. In vitro transcription of the recombinant vector pRS-YF-2A1 was then carried out and introduced into BHK-21 cells by electroporation. Results of indirect immunofluorescence assay (IFA) and titer determination showed a stable infectious recombinant virus was gotten, whose features such as growth curve were similar to those of the parental YF-17D. The results suggest that the recombinant vector pRS-YF-2A1, by introduction of heterogenous genes via 2A region, is potential to be an effective live vaccine expression vector.

The Expression of Human alpha(1,3) Fucosyltransferase in Human Liver Cancer by in situ Hybridization.

The increase of Lewis x and Sialyl Lewis x epitopes on the surface of cancer cells was known for decades. alpha(1,3) FuT is the key enzyme in the biosynthesis of these epitopes. The increase of the activity of this enzyme was actually found in many cancer tissues, cancer cell lines and the serum of the cancer patients. The recent cloning of the enzyme led to the possibility of the application of the sensitive methods with small amount of tissues to detect the expression of the gene. In this paper, probes for alpha(1,3) FuT type III, V and VI were prepared, and they are 447, 486 and 443 bp in length respectively. The DIG-labeled probe (type V) was used to detect the mRNA of the enzyme by in situ hybridization. Surgical samples from five patients with metastatic lesions, five cases without metastasis and two normal liver tissues from liver angioma patients were examined. The alpha(1,3) FuT mRNA level was highest in samples with the metasitatic lesion, and lowest in normal tissues and those of the original tumor lesion in them. The difference is very distinct. The possibility of the method to be used in evaluation the prognosis of the disease is discussed.