Abstract. Previously, we reported that hypoxia was able to induce invasion and metastasis in gastric cancer and that hypoxia-inducible factor-1 (HIF-1) is a key factor involved in this tumor type. Krüppel-like factor 8 (KLF8) as a transcriptional repressor has been suggested as a promoter of tumor metastasis in breast cancer and an inducer of the epithelial-mesenchymal transition (EMT). KLF8 is also highly expressed in gastric cancer tissues, contributing to poor prognosis. However, the association between KLF8 and HIF-1 in regulating the progression of human gastric cancer in hypoxia is unclear. In the present study, we found that KLF8 was overexpressed in gastric cancer metastatic tissues and cells. Additionally, KLF8 siRNA significantly inhibited SGC7901 cell invasion and migration compared with SGC7901, SGC7901/Scr-si cells. Hypoxia is thus able to induce KLF8 expression and EMT in SGC7901 cells. However, following the examination of changes in cell morphology and epithelial and mesenchymal markers, it was found that KLF8 siRNA and HIF-1 siRNA strongly reversed EMT in cells undergoing hypoxia. Furthermore, hypoxia-induced KLF8 overexpression was attenuated by HIF-1 siRNA. Experiments using luciferase promoter constructs resulted in a marked increase in the activity of cells exposed to hypoxia and decreased activity in cells co-transfected with HIF-1 siRNA. The chromatin immunoprecipitation assay revealed proximal HRE at -133 is the main HIF-1 binding site in the KLF8 promoter.In conclusion, the results demonstrated that KLF8 is actively enhanced by hypoxia and is a novel HIF-1 target. KLF8 is a novel EMT regulating transcription factor that involved in the progression of gastric cancer. The specific anti-EMT drugs in combination with anti-hypoxia are new promising cancer therapies.

We found that the transcription factor Krüppel-like factor 8 (KLF8) was highly expressed in gastric cancer tissues and cell lines compared with adjacent noncancerous regions and gastric epithelial mucosa cells. We employed a lentivirus-mediated RNAi technique to knockdown KLF8 expression in gastric cancer cell line SGC7901 and observed its effects on cell growth in vitro and in vivo. Knockdown of KLF8 inhibited SGC7901 cell proliferation, promoted cell apoptosis, inhibited the tumorigenicity of SGC7901 cells, and significantly decreased tumor growth when the cells were injected into nude mice. These results indicated that overexpression of KLF8 may influence the biological behavior of SGC7901 gastric cancer cells. Knockdown of KLF8 expression by lentivirus-delivered siRNA may be useful as a therapeutic agent for the treatment of gastric cancer.

Bone is one of the most frequent targets of small cell lung cancer (SCLC) metastasis and is closely associated with a poor prognosis, but the specific cellular gene alterations responsible for SCLC with bone metastasis are unclear. Zinc finger E-box binding homeobox 1 (ZEB1) as an E-box transcriptional repressor has been suggested that an important inducer of the epithelial-mesenchymal transition (EMT) and a promoter of tumor metastasis in colon, breast and lung cancers. However, the relationship between ZEB1 and SCLC with bone metastasis is unclear. In this study, ZEB1 was found to be highly expressed in bone-metastatic SCLC tissues and cell lines as compared with those that were non-metastatic (P < 0.05). Using a lentivirus RNA interference technique to knockdown ZEB1 expression in bone-metastatic SCLC cells (SBC-5 cell line), we found that ZEB1 siRNA could inhibit the invasive and migratory ability and decrease parathyroid hormone-related protein expression, as determined by invasion assays and enzyme-linked immunosorbent assays. Besides, ZEB1 siRNA significantly inhibited the bone metastasis of SBC-5 cells in vivo. Furthermore, overexpression of ZEB1 in SBC-3 cells, which demonstrate promoted bone-metastatic potential, dramatically promoted their invasive and migratory ability and parathyroid hormone-related proteinexpression as well as increased the number and sites of bone metastases in vivo compare to the control group. We also found that SBC-3 cells underwent EMT, as indicated by decreased epithelial markers and increased mesenchymal marker expression. Taken together, these results indicate that ZEB1 promoted the invasive ability and bone metastasis of SCLC cells, and that this was partially mediated via the EMT pathway. (Cancer Sci 2012; 103: 1420-1428 S mall cell lung cancer (SCLC) is the lung neoplasia with the poorest prognosis, due to its high ability of metastasis. SCLC in the advanced stage frequently metastasizes to multiple organs, including the liver, lungs, lymph nodes and bone.( 1) Bone is one of the most frequent targets of SCLC metastasis (as well as the brain and liver) and the bone metastasis is associated with high morbidity and poor prognosis (2,3) due to the consequences of skeletal-related events, including bone pain, pathologic and radiologic fractures and hypercalcemia. (4)(5)(6) However, the mechanisms underlying this rapid metastatic capacity of SCLC are unknown.Previous study shows that SBC-3 and SBC-5 are derived a similar genetic background from human SCLC, which have the same metastatic ablility of visceral organs except for bone. SBC-5 has a higher capability of bone metastasis than SBC-3.(7) We previously explored the preliminary mechanism of bone metastasis using SBC-5 and SBC-3. (8)(9)(10) Zinc finger E-box binding homeobox 1 (ZEB1) is an E-box transcriptional inducer that has emerged as a key player in cancer progression. The epithelial-mesenchymal transition (EMT) plays an important role in tumor invasion and is closely related with development and progression of tumors....

Lung cancer is the most common malignant tumor in China. It often metastasizes to bone, thereby significantly shortening the lives of patients, and reducing their quality of life. However, the efficacy of treatment for bone metastasis of lung cancer at this stage is very limited. The development and clinical application of molecular-targeted drugs for the effective targeted therapy of bone metastasis of lung cancer are urgently required. The growth differentiation factor 15 (GDF15) gene which may be associated with bone metastasis of lung cancer, was screened out by whole-genome sequencing. In the present study, we used a recombinant GDF15 lentivirus technique to upregulate the expression of GDF15 in lung adenocarcinoma A549 cells, and the results revealed that GDF15 could inhibit the proliferation, migration and invasion, while promoting apoptosis of A549 cells. In addition, GDF15 significantly decreased the number and sites of lung metastases and bone metastases in vivo compared to the control group. Finally, it was revealed that Smad2 and phospho-Smad2 protein expression was lower in the GDF15-overexpressing A549 cells. This result indicated that the tumor suppressive effect of GDF15 may be related to the TGF-β/Smad signaling pathway, although more studies are still required for confirmation. In summary, GDF15 inhibited the growth and bone metastasis of lung adenocarcinoma A549 cells, and this effect may be achieved through the TGF-β/Smad signaling pathway.

Background Given the increasing use of immune checkpoint inhibitors (ICIs), a concomitant rise in adverse events is inevitable. In a recent Phase III trial of ICIs versus placebo, we found the staggering difference of incidence of fatal adverse events (FAEs). Hence, we should determine the risk of FAEs in ICIs. Objective To address the risks of FAEs associated with each ICI regimen, we performed a systematic review and meta-analysis of clinical trials with the Food and Drug Administration-approved ICI regimens in patients with advanced solid tumors. Methods Literature searching was based on PubMed before April 15, 2018. The numbers of FAEs in both study group and placebo group were collected. We assessed the risk of fatal adverse reactions associated with ICIs on Pooled Peto OR and associated 95% CI. Results Twelve trials were identified. OR value of FADs in all ICIs was 2.32 (95% CI: 1.33, 4.05; P =0.003). The incidence of FAE in ICI in all included studies were up to 3.2%. OR value of clinical trials of prostate cancer was 3.71 (95% CI: 1.12, 12.26; P =0.03). Among the ICI cohorts, the common FAEs were gastrointestinal toxicity (n=12, 25%), pulmonary toxicity (n=10, 20%), cardiac toxicity (n=5, 10%), and hepatic toxicity (n=5, 10%). Conclusion The cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) inhibitors have a significantly higher risk of FAE ( P =0.01), whereas programmed cell death protein 1 (PD-1) inhibitors were not. The most common CTLA-4-related FAE was gastrointestinal toxicity, and the most common PD-1-related FAE was pulmonary toxicity. Moreover, we have shown that ipilimumab has significant dose-dependent lethal toxicity.