Xinyuan Liu

Spectrum of oncogenic driver mutations in lung adenocarcinomas from East Asian never smokers.

Purpose We previously showed that 90% (47 of 52; 95% CI, 0.79 to 0.96) of lung adenocarcinomas from East Asian never-smokers harbored well-known oncogenic mutations in just four genes: EGFR, HER2, ALK, and KRAS. Here, we sought to extend these findings to more samples and identify driver alterations in tumors negative for these mutations. Experimental Design We have collected and analyzed 202 resected lung adenocarcinomas from never smokers seen at Fudan University Shanghai Cancer Center. Since mutations were mutually exclusive in the first 52 examined, we determined the status of EGFR, KRAS, HER2, ALK, and BRAF in stepwise fashion as previously described. Samples negative for mutations in these 5 genes were subsequently examined for known ROS1 fusions by RT-PCR and direct sequencing. Results 152 tumors (75.3%) harbored EGFR mutations, 12 (6%) had HER2 mutations, 10 (5%) had ALK fusions all involving EML4 as the 5′ partner, 4 (2%) had KRAS mutations, and 2 (1%) harbored ROS1 fusions. No BRAF mutation were detected. Conclusion The vast majority (176 of 202; 87.1%, 95% CI: 0.82 to 0.91) of lung adenocarcinomas from never smokers harbor mutant kinases sensitive to available TKIs. Interestingly, patients with EGFR mutant patients tend to be older than those without EGFR mutations (58.3 Vs 54.3, P = 0.016) and patient without any known oncogenic driver tend to be diagnosed at a younger age (52.3 Vs 57.9, P = 0.013). Collectively, these data indicate that the majority of never smokers with lung adenocarcinoma could benefit from treatment with a specific tyrosine kinase inhibitor.

Cobalt chloride induces PC12 cells apoptosis through reactive oxygen species and accompanied by AP-1 activation.

Reactive oxygen species (ROS) are supposed to play an important role in hypoxia‐ and ischemia/reperfusion‐mediated neuronal injury with the characteristics of apoptosis. There are many reports showing that cobalt chloride (CoCl2) could mimic the hypoxic responses in some aspects including production of ROS in cultured cells. The cytotoxicity of CoCl2 and its molecular mechanisms have yet to be elucidated. We report that CoCl2 triggered neuronal PC12 cells apoptosis in a dose‐ and time‐dependent manner. Apoptosis was demonstrated by morphological changes and DNA fragmentation, and was dependent on macromolecular synthesis. Apoptosis was also confirmed by the decrease of the expression of Bcl‐XL. To our knowledge, this is the first documentation of the apoptotic induction of CoCl2 on PC12 cells. Furthermore, ROS production in PC12 cells was increased during CoCl2 treatment. Antioxidants, which could inhibit ROS production, significantly blocked CoCl2‐induced apoptosis, suggesting that apoptosis is mediated by ROS production. We also observed a significant increase of the DNA‐binding activity of AP‐1 in response to CoCl2 and this increase was blocked by antioxidants, showing that CoCl2‐induced apoptosis is accompanied by ROS‐activated AP‐1. CoCl2‐treated PC12 cells may serve as an in vitro model for studies of molecular mechanisms in ROS‐linked neuronal disorders. J. Neurosci. Res. 64:646–653, 2001.

An oncolytic adenoviral vector of Smac increases antitumor activity of TRAIL against HCC in human cells and in mice.

Hepatocellular carcinoma (HCC) displays a high resistance to tumor necrosis factor–related apoptosis–inducing ligand (TRAIL)–mediated cell death. To increase sensitivity of HCC cells to TRAIL, we have constructed an oncolytic adenoviral vector (ZD55) and used this vector to deliver second mitochondria‐derived activator of caspases (Smac) and TRAIL genes (ZD55‐Smac and ZD55‐TRAIL, respectively) into HCC cells. Our data showed that human HCC cells express high levels of inhibitor of apoptosis proteins (IAPs). Transfected HCC cells expressing exogenous X‐linked IAPs (XIAPs) displayed more resistance to TRAIL. The expression of Smac led to rapid and potent activation of apoptosis in HCC cells after infection with ZD55‐Smac. The activation of caspases and induction of apoptosis could be enhanced further through coinfection with ZD55‐TRAIL. The combined treatment of ZD55‐Smac and ZD55‐TRAIL resulted in significant reduction of XIAP expression levels. In addition, our in vivo data in mice showed only a partial response in the established tumor treated either by ZD55‐Smac or ZD55‐TRAIL alone. By contrast, complete tumor regression was observed by combination of ZD55‐Smac and ZD55‐TRAIL in all treated animals. This strong antitumoral activity achieved by this combination was due to a dramatic induction of tumor cell apoptosis in the treated tumors. In conclusion, our data indicate that Smac antagonizes the IAPs in HCC tumor cells and enhances tumor cell death induced by TRAIL in the oncolytic adenoviral vector. The combination of Smac and TRAIL delivered by way of the oncolytic adenoviral vector would provide a useful strategy for therapy of HCC and might also be applied to other IAPs abundant in cancers. (HEPATOLOGY 2004;39:1371–1381.)

MicroRNA-143 (miR-143) Regulates Cancer Glycolysis via Targeting Hexokinase 2 Gene

Background: Hexokinase 2 (HK2) is frequently overexpressed in malignant tumors. Results: miR-143 down-regulates HK2 and inhibits glucose metabolism and cancer progression. Conclusion: miR-143 is an essential regulator of cancer glycolysis via targeting HK2. Significance: Discovering the important role of miRNA in cancer metabolism may provide potential targets for cancer therapy. High glycolysis, well known as “Warburg effect,” is frequently observed in a variety of cancers. Whether the deregulation of miRNAs contributes to the Warburg effect remains largely unknown. Because miRNA regulates gene expression at both mRNA and protein levels, we constructed a gene functional association network, which allows us to detect the gene activity instead of gene expression, to integratively analyze the microarray data for gene expression and miRNA expression profiling and identify glycolysis-related gene-miRNA pairs deregulated in cancer. Hexokinase 2 (HK2), coding for the first rate-limiting enzyme of glycolysis, is among the top list of genes predicted and potentially regulated by multiple miRNAs including miR-143. Interestingly, miR-143 expression was inversely associated with HK2 protein level but not mRNA level in human lung cancer samples. miR-143, down-regulated by mammalian target of rapamycin activation, reduces glucose metabolism and inhibits cancer cell proliferation and tumor formation through targeting HK2. Collectively, we have not only established a novel methodology for gene-miRNA pair prediction but also identified miR-143 as an essential regulator of cancer glycolysis via targeting HK2.

An armed oncolytic adenovirus system, ZD55-gene, demonstrating potent antitumoral efficacy

ABSTRACTONYX-015 is an attractive therapeutic adenovirus for cancer because it can selectively replicate in tumor cells and kill them. To date, clinical trials of this adenovirus have demonstrated marked safety but not potent enough when it was used alone. In this paper, we put forward a novel concept of Gene-ViroTherapy strategy and in this way, we constructed an armed therapeutic oncolytic adenovirus system, ZD55-gene, which is not only deleted of E1B 55-kD gene similar to ONYX-015, but also armed with foreign antitumor gene. ZD55-gene exhibited similar cytopathic effects and replication kinetics to that of ONYX-015 in vitro. Importantly, the carried gene is expressed and the expression level can increase with the replication of virus. Consequently, a significant antitumoral efficacy was observed when ZD55-CD/5-FU was used as an example in nude mice with subcutaneous human SW620 colon cancer. Our data demonstrated that ZD55-gene, which utilizing the Gene-ViroTherapy strategy, is more efficacious than each individual component in vivo.

Ras-related protein Rab10 facilitates TLR4 signaling by promoting replenishment of TLR4 onto the plasma membrane

The Toll-like receptor (TLR)4 receptor complex, TLR4/MD-2, plays an important role in the inflammatory response against lipopolysaccharide, a ubiquitous membrane component in Gram-negative bacteria. Ligand recognition by TLR4 initiates multiple intracellular signaling pathways, leading to production of proinflammatory mediators and type I IFN. Ligand interaction also leads to internalization of the surface receptor complex into lysosomes, leading to the degradation of TLR4 and the termination of LPS response. However, surface level of TLR4 receptor complex is maintained via continuous replenishment of TLR4 from intracellular compartments like Golgi and endosomes. Here we show that continuous replenishment of TLR4 from Golgi to plasma membrane is regulated by the small GTPase Rab10, which is essential for optimal macrophage activation following LPS stimulation. Expression of Rab10 is inducible by LPS. Blockade of Rab10 function leads to decreased membrane TLR4 expression and diminished production of inflammatory cytokines and interferons upon LPS stimulation. These findings suggest that Rab10 expression provides a mechanism to refine TLR4 signaling by regulating the trafficking rate of TLR4 onto the plasma membrane. In addition, we show that altered Rab10 expression in macrophages influences disease severity in an in vivo model of LPS-induced acute lung injury, suggesting Rab10 as a possible therapeutic target for human acute respiratory distress syndrome (ARDS).

Generation of haploid embryonic stem cells from Macaca fascicularis monkey parthenotes

Recent success in the derivation of haploid embryonic stem cells (haESCs) from mouse via parthenogenesis and androgenesis has enabled genetic screening in mammalian cells and generation of gene-modified animals. However, whether haESCs can be derived from primates remains unknown. Here, we report the derivation of haESCs from parthenogenetic blastocysts of Macaca fascicularis monkeys. These cells, termed as PG-haESCs, are pluripotent and can differentiate to cells of three embryonic germ layers in vitro or in vivo. Interestingly, the haploidy of one monkey PG-haESC line (MPH1) is more stable compared with that of the other one (MPH2), as shown by the existence of haploid cells for more than 140 days without fluorescence-activated cell sorting (FACS) enrichment of haploid cells. Importantly, transgenic monkey PG-haESC lines can be generated by lentivirus- and piggyBac transposon-mediated gene transfer. Moreover, genetic screening is feasible in monkey PG-haESCs. Our results demonstrate that PG-haESCs can be generated from monkeys, providing an ideal tool for genetic analyses in primates.

Copper induces apoptosis in BA/F3β cells: Bax, reactive oxygen species, and NFκB are involved

Copper, an essential trace element, can be toxic to some cells when present in excess. But thorough investigations into the cytotoxicity of copper and subsequent molecular mechanisms are rare, although the cytotoxicity of copper has been applied to cancer chemotherapy. The present study demonstrates that Cu2+ inhibits [3H] thymidine incorporation in mouse pro‐B cell line BA/F3β and induces apoptosis. Apoptosis was mainly judged by morphology of cells, quantification of subdiploid DNA contents by flow cytometry, and detection of DNA fragmentation by gel electrophoresis. The apoptotic effect is dose and time dependent. Western blotting shows Bax is upregulated by Cu2+. Bcl‐2 overexpression can partially inhibit this apoptosis. Moreover, Cu2+ increases the production of reactive oxygen species (ROS) in a dose‐dependent manner. The antioxidant N‐acetylcysteine (NAC) not only significantly inhibited copper‐induced apoptosis but also totally blocked generation of ROS, while Bcl‐2 overexpression has no effect on the generation of ROS. Furthermore, our results show that NFκB is downregulated by Cu2+. Bcl‐2 overexpression or NAC can sustain the activity of NFκB. These data indicate that Cu2+ might induce apoptosis in BA/F3β cells via upregulation of Bax and ROS and subsequent inactivation of NFκB. J. Cell. Physiol. 184:161–170, 2000.

Spectrum of LKB1, EGFR, and KRAS Mutations in Chinese Lung Adenocarcinomas

Introduction: Somatic LKB1 mutations are found in lung adenocarcinomas at different frequencies in Caucasian and East Asian (Japanese and Korean) populations. This study was designed to characterize the frequency of LKB1 mutations, their relationship to EGFR and KRAS mutations, and their associated clinicopathologic characteristics in Chinese patients. Methods: Two hundred thirty-nine lung adenocarcinomas consecutively collected from October 2007 to July 2009 were dissected into 3 to 4 small (3 mm) pieces for histopathological analyses of tumor content. Genomic DNA and/or cDNA from 86 samples with more than 70% tumor content were used for sequencing of LKB1 (exons 1–9), EGFR (exons 18–21), and KRAS (exon 2). LKB1 germline mutation status was determined by sequencing of genomic DNA from matched histologically distant lung tissues that are histologically normal. Results: 6.9% of lung adenocarcinomas harbored LKB1 somatic mutations. A total of 10.5% of patients had an LKB1 germline polymorphism, F354L. Interestingly, in two of these patients, tumors displayed loss of heterozygosity at this allele. EGFR kinase domain and KRAS mutations were found in 66.3% and 2.3% of Chinese lung adenocarcinomas, respectively. Concurrent LKB1 and EGFR somatic mutations were observed in one patient. Both KRAS-mutant tumors harbored LKB1 mutations. Conclusions: These data provide important clinical and molecular characteristics of lung adenocarcinomas from Chinese patients.

A novel oncolytic adenovirus targeting to telomerase activity in tumor cells with potent

Telomerase is a therapeutic target for cancer. Human telomerase reverse transcriptase (hTERT), the catalytic subunit of the telomerase, is transcriptionaly upregulated exclusively in about 90% of cancer cells. Previous studies have demonstrated that hTERT promoter can control the expression of exogenous genes to the telomerase-positive cancer cells, thus hTERT promoter is an excellent candidate for generating cancer-specific oncolytic adenovirus. In this study, we devised a novel oncolytic adenovirus (Ad.TERT) by replacing the normal E1A regulatory elements with hTERT promoter. Ad.TERT displays cancer-specific E1A expression, virus replication and cytolysis in in vitro experiments. In animal experiments, intratumoral administration of Ad.TERT demonstrates potent antitumoral efficacy at least in two xenograft models (Bcap37 and BEL7404). Ad.TERT was targeted by the telomerase activity in cancer cells and has potent antitumoral efficacy in vivo, and since telomerase activity is a wide-ranged tumor marker, Ad.TERT could be a powerful therapeutic agent for a variety of cancers.