PET und PET-CT maligner Tumoren des exokrinen Pankreas

Emodin alleviates gemcitabine resistance in pancreatic cancer by inhibiting MDR1/P-glycoprotein and MRPs expression

Gemcitabine is a gold standard chemotherapeutic agent for pancreatic cancer. However, gemcitabine has limited effectiveness due to the short-term development of chemoresistance. Emodin, a natural anthraquinone derivative isolated from the roots of rheumatic palm leaves prevents immunosuppression and exerts anticancer effects. The present study aimed to evaluate the effect of emodin on gemcitabine resistance. Gemcitabine-resistant PANC-1 pancreatic cancer cell xenografts were established in athymic mice, which were randomly assigned into four treatments groups as follows: Gemcitabine group, Emodin group, Gemcitabine+Emodin group and Negative control group. Body weight, tumor volume and tumor weight were measured over the course of treatment. The effect of each treatment on tumor tissue proliferation and apoptosis from nude mice was evaluated by using immunohistochemistry. The effect of each treatment on the proliferation of gemcitabine-resistant PANC-1 cells was also determined by using the Cell Counting Kit-8. Then, reverse transcription-quantitative (RT-q) PCR and western blotting were used to detect the mRNA and protein expression, respectively, of multidrug resistance gene 1 (MDR1) and the drug resistance-related proteins MRP1 and MRP5. The function and expression level of DR1 gene product, p-glycoprotein, was also analysed by flow cytometry and RT-qPCR, respectively. The results demonstrated that the combination of gemcitabine and emodin significantly reduced xenograft volume and reduced tumor growth in mice compared with treatment with gemcitabine or emodin only. In addition, emodin treatment reduced resistance to gemcitabine, which was characterized by the downregulation of P-glycoprotein, MRP1 and MRP5 expression in the group receiving combination treatment. The level of P-glycoprotein was also decreased in the group treated with gemcitabine+emodin compared with the single treatment groups. Taken together, these results demonstrated that emodin enhanced gemcitabine efficacy in tumor treatment and alleviated gemcitabine resistance in PANC-1 cell xenografts in mice via suppressing MDR1/P-glycoprotein and MRP expression.

Effects of emodin on the demethylation of tumor-suppressor genes in pancreatic cancer PANC-1 cells

Emodin, a natural anthraquinone derivative isolated from Rheum palmatum, has been reported to inhibit the growth of pancreatic cancer cells through different modes of action; yet, the detailed mechanism remains unclear. In the present study, we hypothesized that emodin exerts its antitumor effect by participating in the regulation of the DNA methylation level. Our research showed that emodin inhibited the growth of pancreatic cancer PANC-1 cells in a dose- and time-dependent manner. Dot-blot results showed that 40 µM emodin significantly inhibited genomic 5 mC expression in the PANC-1 cells, and mRNA-Seq showed that different concentrations of emodin could alter the gene expression profile in the PANC-1 cells. BSP confirmed that the methylation levels of P16, RASSF1A and ppENK were decreased, while concomitantly the unmethylated status was increased. RT-PCR and western blotting results confirmed that the low expression or absence of expression of mRNA and protein in the PANC-1 cells was re-expressed following treatment with emodin. In conclusion, our study for the first time suggests that emodin inhibits pancreatic cancer cell growth, which may be related to the demethylation of tumor-suppressor genes. The related mechanism may be through the inhibition of methyltransferase expression.

Emodin sensitizes the gemcitabine-resistant cell line Bxpc-3/Gem to gemcitabine via downregulation of NF-κB and its regulated targets

The aim of this study was to evaluate whether emodin can overcome the chemoresistance of the gemcitabine-resistant cancer cell line (Bxpc-3/Gem) in vitro. The cell line Bxpc-3/Gem was derived from the human pancreatic cancer cell line Bxpc-3. We found that Bxpc-3/Gem cells were characterized by a series of morphological changes with a resistance index of 43.51 comparing with the parental cell line. Emodin reduced Bxpc-3/Gem cell proliferation in a dose-dependent manner. Emodin and gemcitabine combination treatments resulted in decreased cell proliferation and increased apoptosis in Bxpc-3/Gem cells. In addition, combination treatments resulted in downregulation of gene and protein expression of MDR-1 (P-gp), NF-κB, XIAP, survivin, as well as inhibition of NF-κB activity and P-gp function. These observations suggest that emodin may sensitize the pancreatic cancer gemcitabine-resistant cell line Bxpc-3/Gem to gemcitabine therapy via inhibition of survival signaling.

FDG PET and PET/CT

Molecular imaging with positron emission tomography (PET) using tumour-seeking radiopharmaceuticals has gained wide acceptance in oncology with many clinical applications. The hybrid imaging modality PET/CT allows assessing molecular as well as morphologic information at the same time. Therefore, PET/CT represents an efficient tool for whole body staging and re-staging within one imaging modality. In oncology the glucose analogue (18)F-fluorodeoxyglucose (FDG) is the most widely used PET and PET/CT radiopharmaceutical in clinical routine. FDG PET and PET/CT have been used for staging and re-staging tumour patients in numerous studies. This chapter will discuss the use and the main indications of FDG PET and PET/CT in oncology with special emphasis on lung cancer, oesophageal cancer, colorectal cancer, head and neck cancer, lymphoma and breast cancer (among other tumour entities). A review of the current literature will be given with respect to primary diagnosis, staging and diagnosis of recurrent disease (local, lymph node and distant metastases). Besides its integral role in diagnosis, staging and re-staging of disease in oncology, there is increasing evidence that FDG PET and PET/CT can significantly contribute to therapy response assessment possibly influencing therapeutic management and treatment planning, to therapy tumour control and prediction of prognosis in oncologic patients, which will also be discussed in this chapter.