Biology subjects

Han, Z.-G.

Publications and source records attributed to Han, Z.-G..

7 recordsLinked to original sources

bioRxiv2022

Tumor subclones, where are you?

IntroductionTumor clonal structure is closely related to future progression, which has been mainly investigated via mutation abundance clustering in bulk sample. With limited studies at single-cell resolution, a systematic comparison of the two approaches is still lacking. MethodsHere, using bulk and single-cell mutational data from liver and colorectal cancers, we would like to check the possibility of obtaining accurate tumor clonal structures from bulk-level analysis. We checked whether co-mutations determined by single-cell analysis had corresponding bulk variant allele frequency (VAF) peaks. We examined VAF ranges for different groups of co-mutations, and also the possibility of discriminating them. ResultsWhile bulk analysis suggested absence of subclonal peaks and possibly neutral evolution in some cases, single-cell analysis identified co-existing subclones. The overlaps of bulk VAF ranges for co-mutations from different subclones made it difficult to separate them, even with other parameter introduced. The difference between mutation cluster and tumor subclone is accountable for the challenge in bulk clonal deconvolution, especially in case of branched evolution as shown in colorectal cancer. ConclusionComplex subclonal structures and dynamic evolution are hidden under the seemingly clonal neutral pattern at bulk level, suggesting single-cell analysis will be needed to avoid under-estimation of tumor heterogeneity. Research HighlightsO_LIBulk-level mutation abundance clusters are not equal to tumor subclones. C_LIO_LIDifferent groups of co-mutations could not be discriminated at bulk-level. C_LIO_LISingle-cell mutational analysis can identify rather than infer tumor subclones. C_LIO_LICo-existing tumor subclones may have clonal neutral appearance at bulk-level. C_LI Lay summarySystematic comparison of tumor clonal structure differences between bulk and single-cell mutational analysis is lacking. Here we performed such as study and found that complex subclonal structures and dynamic evolution are hidden under clonal neutral appearance at bulk level in liver and colorectal cancers, suggesting single-cell analysis will be needed to avoid under-estimation of tumor heterogeneity.

cancer biology↗

bioRxiv2021

Single-cell and single-variant resolution analysis of clonal evolution in human liver cancer

Genetic heterogeneity of tumor is closely related to clonal evolution, phenotypic diversity and treatment resistance. Such heterogeneity has been characterized in liver cancer at single-cell sub-chromosomal scale, and a more precise single-variant resolution analysis is lacking. Here we employed a strategy to analyze both the single-cell genomic mutations and transcriptomic changes in 5 patients with liver cancer. Target sequencing was done for a total of 480 single cells in a patient-specific manner. DNA copy number status of point mutations was obtained from single-cell mutational profiling. The clonal structures of liver cancers were then uncovered at single-variant resolution, and mutation combinations in single cells enabled reconstruction of their evolutionary history. A common origin but independent evolutionary fate was revealed for primary liver tumor and intrahepatic metastatic portal vein tumor thrombus. The mutational signature suggested early evolutionary process may be related to specific etiology like aristolochic acids. By parallel single-cell RNA-Seq, the transcriptomic phenotype was found to be related with genetic heterogeneity in liver cancer. We reconstructed the single-cell and single-variant resolution clonal evolutionary history of liver cancer, and dissection of both genetic and phenotypic heterogeneity provides knowledge for mechanistic understanding of liver cancer initiation and progression.

genomics↗

bioRxiv2020

Designed peptides as potential fusion inhibitors against SARA-CoV-2 coronavirus infection

Inspired by fusion-inhibitory peptides from heptad repeat 1 (HR1) and heptad repeat 2 (HR2) domains from human immuno-deficiency virus type 1 (HIV-1) envelope glycoprotein gp41 and severe acute respiratory syndrome-coronavirus (SARS-CoV) based on viral fusogenic mechanism in the present work, we provided a similar approach to design the synthesized peptides against the entry into host cells of SARA-CoV-2 virus that causes 2019 novel coronavirus disease (COVID-19). These peptides derived from HR1 and HR2 of SARA-CoV-2 spike protein were further tested for their interaction and potential fusion possibility through circular dichroism spectrum. Here we used the peptide COVID-2019-HR1P1 (40 amino acids) as the target, which was derived from HR1 of SARA-CoV-2 spike protein, while the designed peptides including COVID-2019-HR2P1 (37 amino acids), COVID-2019-HR2P2 (32 amino acids) and others derived from HR2 of SARA-CoV-2 were tested for their binding to COVID-2019-HR1P1. Interestingly, results showed that both COVID-2019-HR2P1 and COVID-2019-HR2P2 can form the complex with COVID-2019-HR1P1, respectively. This implied that these designed peptides could play an important role in blocking SARA-CoV-2 entry into mammalian host cells via viral fusogenic mechanism, and thus could be used for preventing SARA-CoV-2 infection.

microbiology↗

bioRxiv2019

Single-cell dissection of a rare human prostate basal cell carcinoma

As a rare subtype of prostate carcinoma, basal cell carcinoma (BCC) has not been studied extensively and thus lacks systematic molecular characterization. Here we applied single-cell genomic amplification and RNA-Seq to a specimen of human prostate BCC (CK34{beta}E12+/P63+/PAP-/PSA-). The mutational landscape was obtained via whole exome sequencing of the amplification mixture of 49 single cells, and the 5 putative driver genes mutated are CASC5, NUTM1, PTPRC, KMT2C and TBX3. The top 3 nucleotide substitutions are C>T, T>C and C>A, similar to common prostate cancer. The distribution of the variant allele frequency values indicated these single cells are from the same tumor clone. The transcriptomes of 69 single cells were obtained, and they were clustered into tumor, stromal and immune cells based on their global transcriptomic profiles. The tumor cells specifically express basal cell markers like KRT5, KRT14 and KRT23, and epithelial markers EPCAM, CDH1 and CD24. The transcription factor (TF) co-variance network analysis showed that the BCC tumor cells have distinct regulatory networks. By comparison with current prostate cancer datasets, we found that some of the bulk samples exhibit basal-cell signatures. Interestingly, at single-cell resolution the gene expression patterns of prostate BCC tumor cells show uniqueness compared with that of common prostate cancer-derived circulating tumor cells. This study, for the first time, discloses the comprehensive mutational and transcriptomic landscapes of prostate BCC, which lays a foundation for the understanding of its tumorigenesis mechanism and provides new insights into prostate cancers in general.

cancer biology↗

bioRxiv2019

ARID1a protects against steatosis and insulin resistance via PPARalpha-mediated fatty acid oxidation

Non-alcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH) have become a worldwide health concern because of lifestyle changes, but it is still lack of specific therapeutic strategies as the underlying molecular mechanisms remain poorly understood. Our previous study indicated that deficiency of Arid1a, a key component of SWI/SNF chromatin remodeling complex, initiated mouse steatohepatitis, implying that Arid1a might be essentially required for the integrity of hepatic lipid metabolism. However, the exact mechanisms of the pathological process due to Arid1a loss are unclear. In the present work, we show that hepatocyte-specific deletion of Arid1a significantly increases susceptibility to develop hepatic steatosis and insulin resistance in mice fed with high-fat diet (HFD), along with the aggravated inflammatory responses marked by increment of serum alanine amino transferase (AST), aspartate amino transferase (AST) and TNF. Mechanistically, Arid1a deficiency leads to the reduction of chromatin modification characteristic of transcriptional activation on multiple metabolic genes, especially Cpt1a and Acox1, two rate-limiting enzyme genes for fatty acid oxidation. Furthermore, our data indicated that Arid1a loss promotes hepatic steatosis by downregulating PPAR, thereby impairing fatty acid oxidation which leads to lipid accumulation and insulin resistance. These findings reveal that targeting ARID1a might be a promising therapeutic strategy for NAFLD, NASH and insulin resistance.

cell biology↗

bioRxiv2018

The mutational features of aristolochic acid-induced mouse and human liver cancers

Aristolochic acid (AA) derived from traditional Chinese herbal remedies has recently been statistically associated with human liver cancer; however, the causal relationships between AA and liver cancer and the underlying evolutionary process of AA-mediated mutagenesis during tumorigenesis are obscure. Here, we subjected mice, including Pten-deficient ones, to aristolochic acid I (AAI) alone or a combination of AAI and carbon tetrachloride (CCl4), which may induce liver injury. Significantly, AAI promoted the development of liver cancer, including hepatocellular carcinoma and intrahepatic cholangiocarcinoma, in a dose-dependent manner, and it increased the incidence of liver cancer, together with CCl4 or Pten deficiency. AAI could lead to DNA damage and AAI-DNA adducts that initiate liver cancer via characteristic A>T transversions, as indicated by the comprehensive genomic analysis, which revealed recurrent mutations in Hras and some genes encoding components of the Ras/Raf, PI3K, Notch, Hippo, Wnt, DNA polymerase family and the SWI/SNF complex, some of which are also often found in human liver cancer. Mutational signature analysis across human cancer types revealed that the AA-related dominant signature was especially implicated in liver cancer in China, based on very stringent criteria derived from the animal cancer form, in which mutations of TP53 and JAK1 are prone to be significantly enriched. Interestingly, AAI-mediated characteristic A>T mutations were the earliest genetic event driving malignant subclonal evolution in mouse and human liver cancer. In general, this study provides documented evidence for AA-induced liver cancer with featured mutational processes during malignant clonal evolution, laying a solid foundation for the prevention and diagnosis of AA-associated human cancers, especially liver cancer.

cancer biology↗

bioRxiv2018

scMerge: Integration of multiple single-cell transcriptomics datasets leveraging stable expression and pseudo-replication

Concerted examination of multiple collections of single cell RNA-Seq (scRNA-Seq) data promises further biological insights that cannot be uncovered with individual datasets. However, such integrative analyses are challenging and require sophisticated methodologies. To enable effective interrogation of multiple scRNA-Seq datasets, we have developed a novel algorithm, named scMerge, that removes unwanted variation by combining stably expressed genes and utilizing pseudo-replicates across datasets. Analysis of large collections of publicly available datasets demonstrates that scMerge performs well in multiple scenarios and enhances biological discovery, including inferring cell developmental trajectories.

bioinformatics↗