MicroRNAs: A novel signature in the metastasis of esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is a malignant epithelial tumor, characterized by squamous cell differentiation, it is the sixth leading cause of cancer-related deaths globally. The increased mortality rate of ESCC patients is predominantly due to the advanced stage of the disease when discovered, coupled with higher risk of metastasis, which is an exceedingly malignant characteristic of cancer, frequently leading to a high mortality rate. Unfortunately, there is currently no specific and effective marker to predict and treat metastasis in ESCC. MicroRNAs (miRNAs) are a class of small non-coding RNA molecules, approximately 22 nucleotides in length. miRNAs are vital in modulating gene expression and serve pivotal regulatory roles in the occurrence, progression, and prognosis of cancer. Here, we have examined the literature to highlight the intimate correlations between miRNAs and ESCC metastasis, and show that ESCC metastasis is predominantly regulated or regulated by genetic and epigenetic factors. This review proposes a potential role for miRNAs as diagnostic and therapeutic biomarkers for metastasis in ESCC metastasis, with the ultimate aim of reducing the mortality rate among patients with ESCC.

Atomically Precise Gold-Levonorgestrel Nanocluster as a Radiosensitizer for Enhanced Cancer Therapy

Gold nanoclusters have become promising radiosensitizers due to their ultrasmall size and robust ability to adsorb, scatter, and re-emit radiation. However, most of the previously reported gold nanocluster radiosensitizers do not have a precise atomic structure, causing difficulties in understanding the structure-activity relationship. In this study, a structurally defined gold-levonorgestrel nanocluster consisting of Au₈(C₂₁H₂₇O₂)₈ (Au₈NC) with bright luminescence (58.7% quantum yield) and satisfactory biocompatibility was demonstrated as a nanoradiosensitizer. When the Au₈NCs were irradiated with X-rays, they produced reactive oxygen species (ROS), resulting in irreversible cell apoptosis. As indicated by in vivo tumor formation experiments, tumorigenicity was significantly suppressed after one radiotherapy treatment with the Au₈NCs. In addition, compared with tumors treated with X-rays (4 Gy) alone, tumors treated with the nanosensitizer exhibited an inhibition rate of 74.2%. This study contributes to the development of atomically precise gold nanoclusters as efficient radiosensitizers.

Progress in research of polymorphisms of genes associated with susceptibility to esophageal cancer in Chinese Han population

Esophageal squamous cell carcinoma (ESCC) is one of most common malignant tumors in China, and the polymorphisms of genes associated with susceptibility to ESCC are important factors affecting individual tumor susceptibility. Genes associated with susceptibility to ESCC in Chinese Han population mainly contain metabolizing enzyme-associated genes, nucleotide excision repair genes, methylenetetrahydrofolate reductase gene, tumor suppressor genes, oncogenes, and cytokines. The genotypes of genes associated with susceptibility to ESCC have obvious regional distribution in Chinese Han population. This review aims to summarize and analyze the polymorphisms of genes associated with susceptibility to ESCC, including tumor suppressor genes and genes encoding oncogenes and cytokines, in Chinese Han population.

Molecular cloning and sequence analysis of full-length growth hormone cDNAs from six important economic fishes

In this study,the full-length cDNAs of GH (Growth Hormone) gene was isolated from six important economic fishes, Siniperca kneri, Epinephelus coioides, Monopterus albus, Silurus asotus, Misgurnus anguillicaudatus and Carassius auratus gibelio Bloch. It is the first time to clone these GH sequences except E. coioides GH. The lengths of the above cDNAs are as follows: 953 bp, 1 023 bp, 825 bp, 1 082 bp, 1 154 bp and 1 180 bp. Each sequence includes an ORF of about 600 bp which encodes a protein of about 200 amino acid: S. kneri, E. coioides and M. albus GHs of 204 amino acid, S. asotus GH of 200 amino acid, M. anguillicaudatus and C. auratus gibelio GHs of 210 amino acid. Then detailed sequence analysis of the six GHs with many other fish sequences was performed. The six sequences all showed high homology to other sequences, especially to sequences within the same order, and many conserved residues were identified, most localized in five domains. The phylogenetic trees (MP and NJ) of many fish GH ORF sequences (including the new six) with Amia calva as outgroup were generally resolved and largely congruent with the morphology-based tree though some incongruities were observed, suggesting GH ORF should be paid more attention to in teleostean phylogeny.

[Polymorphism in intron 2 of crucian carp GH I gene]

High length and nucleotide polymorphisms in intron2 of GH I gene were detected in 162 individuals,which were from seven wild crucian carp colonies, two goldfish colonies and one Fangzheng crucian carp colony. Using denaturating polyareylamide gel electrophoresis (DPAGE) and single-strand conformation polymorphism (SSCP), seven length variants and 15 haplotypes were identified in these fishes. The length types and haplotypes diversity was 4.32% and 9.26%, respectively. Sequence analysis of the 15 haplotypes indicated the following results: (1) The size of intron2 varied from 243 to 263 bp. In the 15 haplotypes,the average percentages of the four bases (A,T,G and C) were 34.13%, 37.36%, 15.13% and 13.38%, respectively; the frequency of G + C(28.51%) was much lower than that of A + T (71.49%). The GT/AG domain was found in exon-intron junctions,which was the 5' and 3' splice donor and acceptor sites in higher eukaryotic gene introns. The similarity sequence of GTAAGTA was located on the junction between exon2 and intron2. And there existed a richer pyrimidine region (TTTGCCTTTTGTTATC) near the 3' end of intron2. (2) The seven length variants (A, B, C, D, E, F and G) were determined to be 189, 196, 204, 205, 206, 207 and 209 bp, respectively. The polymorphism resulted from the variable repeat number of T (N = 0, 8, 9, 10, 11 and 13) and the difference in one or two motifs deletions of TGAAAAC, TT and GAGTG. (3) Compared the sequences of the 15 haplotypes, 17 substitution sites were observed, of which two were of transversion sites and 15 were of transition sites. Obviously, the transition mutations (88.24%) were more frequent than transversion mutations (11.76%). Analysis of the distributions of the length types, haplotypes and composite genotypes suggested that genetic diversity was varied in different colonies. In the goldfish colonies, only one length type (A), two haplotypes (A1 and A2) and one composite genotype (A1A2) were observed. Two length types (C and D), four haplotypes (C1, C2, D2 and D5) and one composite genotype (C1C2D2D5) presented in the Fangzheng crucian carp colonies. The highest level of genetic diversity was exhibited in the seven wild crucian carp colonies: seven length types (A, B, C, D, E, F and G), 14 haplotypes (A1, A2, A3, B, C1, C2, D1, D2, D3, D4, E1, E2, F and G) and 14 composite genotypes (A1A2A3, A1A2A3B, A1C1C2D1D2D3, A1C1C2D2, A1C1C2D2D3, A1C1C2D3E2, BC1C2D2, BC1C2D3D4, C1C2D2, C1C2D2D3, C1C2D3D4, C1C2D3D4F, C1C2D4, D2E1G) were shared by the seven wild colonies. The numbers of observed length types, haplotypes and genotypes within the wild colonies ranged from 3 to 6, 6 to 10 and 2 to 6, respectively. Whether the length and nucleotide polymorphisms in the intron2 of crucian carp GH I gene were associated with gene expression and gene regulation remained unsolved and required further investigations.

Clinicopathological and molecular genetic analysis of 4 typical Chinese HNPCC families

AIM: To study the clinicopathological and mole cular genetic characteristics of typical Chinese hereditary nonpolyposis cotorectal cancer (HNPCC) families.

METHODS: Four typical Chinese HNPCC families were analyzed using microdissection, microsatellite instability analysis, immunostaining of hMSH2 and hMLH1 proteins and direct DNA sequencing of hMSH2 and hMLH1 genes.

RESULTS: All five tumor tissues of 4 probands from the 4 typical Chinese HNPCC families showed microsatellite instability at more than two loci (MSI-H or RER+ phenotype). Three out of the 4 cases lost hMSH2 protein expression and the other case showed no hMLH1 protein expression. Three pathological germline mutations (2 in hMSH2 and 1 in hMLH1), which had not been reported previously, were identified. The same mutations were also found in other affected members of two HNPCC families, respectively.

CONCLUSION: Typical Chinese HNPCC families showed relatively frequent germline mutation of mismatch repair genes. High-level microsatellite instability and loss of expression of mismatch repair genes correlated closely with germline mutation of mismatch repair genes. Microsatellite instability analysis and immunostaining of mismatch repair gene might serve as effective screening methods before direct DNA sequencing. It is necessary to establish clinical criteria and molecular diagnostic strategies more suitable for Chinese HNPCC families.

New lactone-containing metabolites from a marine-derived bacterium of the genus Streptomyces

Six novel metabolites containing a lactone moiety as a common structural feature, along with the previously described (-)-blastmycinolactol, have been isolated from the cultivation broth of a bacterium of the genus Streptomyces isolated from marine sediment. On the basis of the results of combined spectroscopic analysis, the structures of the new compounds have been determined as butenolides and 3-hydroxy-gamma-butyrolactones.