Biology subjects

Lai, A. G.

Publications and source records attributed to Lai, A. G..

4 recordsLinked to original sources

bioRxiv2018

A novel signature derived from immunoregulatory and hypoxia genes predicts prognosis in liver and five other cancers

BackgroundDespite much progress in cancer research, its incidence and mortality continue to rise. A robust biomarker that would predict tumor behavior is highly desirable and could improve patient treatment and prognosis.\n\nMethodsIn a retrospective bioinformatics analysis involving patients with liver cancer (n=839), we developed a prognostic signature consisting of 45 genes associated with tumor-infiltrating lymphocytes and cellular responses to hypoxia. From this gene set, we were able to identify a second prognostic signature comprised of 8 genes. Its performance was further validated in five other cancers: head and neck (n=520), renal papillary cell (n=290), lung (n=515), pancreas (n=178) and endometrial (n=370).\n\nFindingsThe 45-gene signature predicted overall survival in three liver cancer cohorts: hazard ratio (HR)=1.82, P=0.006; HR=1.84, P=0.008 and HR=2.67, P=0.003. Additionally, the reduced 8-gene signature was sufficient and effective in predicting survival in liver and five other cancers: liver (HR=2.36, P=0.0003; HR=2.43, P=0.0002 and HR=3.45, P=0.0007), head and neck (HR=1.64, P=0.004), renal papillary cell (HR=2.31, P=0.04), lung (HR=1.45, P=0.03), pancreas (HR=1.96, P=0.006) and endometrial (HR=2.33, P=0.003). Receiver operating characteristic analyses demonstrated both signatures superior performance over current tumor staging parameters. Multivariate Cox regression analyses revealed that both 45-gene and 8-gene signatures were independent of other clinicopathological features in these cancers. Combining the gene signatures with somatic mutation profiles increased their prognostic ability.\n\nConclusionsThis study, to our knowledge, is the first to identify a gene signature uniting both tumor hypoxia and lymphocytic infiltration as a prognostic determinant in six cancer types (n=2,712). The 8-gene signature can be used for patient risk stratification by incorporating hypoxia information to aid clinical decision making.

cancer biology↗

bioRxiv2018

Prognostic signatures of oxygen-sensing genes predict patient survival in ten cancers including those of the liver, pancreas and stomach

ObjectivesTumor hypoxia is associated with metastasis and resistance to chemotherapy and radiotherapy. Genes involved in oxygen-sensing are clinically relevant and have significant implications on prognosis.\n\nMethodsWe identified of two signatures, signature 1 (good prognosis) and signature 2 (adverse prognosis), each consisting of 5 genes using three pancreatic cancer cohorts (n=681). We validated the signatures performance in predicting survival in ten cancers using Cox regression and receiver operating characteristic (ROC) analyses.\n\nResultsSignature 1 and signature 2 were associated with good and poor overall survival respectively. Prognosis of signature 1 in 8 cohorts representing 6 cancers (n=2,627): bladder (hazard ratio [HR]=0.68, P=0.039), papillary renal cell (HR=0.35, P=0.013), liver (HR=0.64, P=0.033 and HR=0.49, P=0.025), lung (HR=0.66, P=0.014) and pancreatic (HR=0.42, P<0.001 and HR=0.64, P=0.04) and endometrial (HR=0.40, P<0.001). Prognosis of signature 2 in 12 cohorts representing 9 cancers (n=4,134): bladder (HR=1.46, P=0.039), cervical (HR=1.97, P=0.035), head and neck (HR=1.39, P=0.038), renal clear cell (HR=1.47, P=0.012), papillary renal cell (HR=3.89, P=0.0015), liver (HR=5.10, P<0.0001 and HR=2.26, P<0.001), lung (HR=1.54, P=0.011), pancreatic (HR=2.09, P=0.002, HR=1.46, P=0.018, and HR=1.99, P<0.0001) and stomach (HR=1.78, P=0.004). Multivariate Cox regression confirmed independent clinical relevance of signatures in these cancers. ROC analyses confirmed superior performance of signatures to current tumor staging benchmarks. KDM8 is a potential tumor suppressor downregulated in liver and pancreatic cancers and is an independent prognostic factor. KDM8 expression negatively correlated with cell cycle regulators. Low KDM8 in tumors was associated with loss of cell adhesion phenotype through HNF4A signaling.\n\nConclusionsPan-cancer signatures of oxygen-sensing genes used for risk assessment in 10 cancers (n=6,761) could guide individualized treatment plans.

cancer biology↗

bioRxiv2016

The innate immune systems of malacostracan crustaceans exhibit both conserved and evolutionarily distinct components

Growing demands for aquatic sources of animal proteins have attracted significant investments in aquaculture research in recent years. The crustacean aquaculture industry has undergone substantial growth to accommodate a rising global demand, however such large-scale production is susceptible to pathogen-mediated destruction. It is clear that a thorough understanding of the crustacean innate immune system is imperative for future research into combating current and future pathogens of the main food crop species. Through a comparative genomics approach utilising extant data from 55 species, we describe the innate immune system of crustaceans from the Malacostraca class. We identify 7407 malacostracan genes from 39 gene families implicated in different aspects of host defence and demonstrate dynamic evolution of innate immunity components within this group. Malacostracans have achieved flexibility in recognising infectious agents through divergent evolution and expansion of pathogen recognition receptors genes. Antiviral RNAi, Toll and JAK-STAT signal transduction pathways have remained conserved within Malacostraca, although the Imd pathway appears to lack several key components. Immune effectors such as the antimicrobial peptides (AMPs) have unique evolutionary profiles, with many malacostracan AMPs not found in other arthropod groups. Lastly, we describe four putative novel immune gene families, characterised by distinct protein domains, potentially representing important evolutionary novelties of the malacostracan immune system.

evolutionary biology↗

bioRxiv2016

Analyses of the core eukaryotic protein subunit of telomerase support extensive adaptation to different evolutionary and life histories in the Metazoa

Most animals employ telomerase, which consists of a catalytic subunit known as the telomerase reverse transcriptase (TERT) and an RNA template, to maintain telomere ends. Given the importance of TERT and the apparent importance of telomere biology in core metazoan life history traits like ageing and the control of somatic cell proliferation, we hypothesised that TERT would have patterns of sequence and regulatory evolution reflecting adaptations to diverse evolutionary and life histories across the Animal Kingdom. To test this, we performed a complete investigation of the evolutionary history of TERT across animals. We show that although TERT is almost ubiquitous across Metazoa, it has undergone substantial sequence evolution in canonical motifs. Beyond the known canonical motifs, we also identify and compare regions that are highly variable between lineages, but for which conservation exists within phyla. Recent data have highlighted the importance of alternate splice forms of TERT in non-canonical functions in some animals. Although animals may share some conserved introns, we find that the selection of exons for alternative splicing appears to be highly variable, and regulation by alternative splicing appears to be a very dynamic feature of TERT evolution. We show that even within a closely related group of triclad flatworms, where alternative splicing of TERT was previously correlated with reproductive strategy, we observe highly diverse alternative splicing patterns. Our work establishes that the evolutionary history and structural evolution of TERT involves previously unappreciated levels of change, supporting the view that this core eukaryotic protein has adapted to the requirements of diverse animal life histories.

evolutionary biology↗