MicroRNAs modulation in lung cancer: exploring dual mechanisms and clinical prospects

The global incidence of lung cancer is marked by a considerably elevated mortality rate.MicroRNAs(miRNAs)exert pivotal influence in the intricate orchestration of gene regulation,and their dysregulation can precipitate dire consequences,notably cancer.Within this context,miRNAs encapsulated in exosomes manifest a diversified impact on the landscape of lung cancer,wherein their actions may either foster angiogenesis,cell proliferation,and metastasis,or counteract these processes.This comprehensive review article discerns potential targets for the prospective development of therapeutic agents tailored for lung cancer.Tumor-suppressive miRNAs,such as miR-204,miR-192,miR-30a,miR-34a,miR-34b,miR-203,and miR-212,exhibit heightened expression and demonstrate the capacity to inhibit cellular proliferation and invasiveness.Conversely,the deleterious effects of tumor-promoting miRNAs like miR-21,miR-106a,miR-155,miR-205,and miR-210 can be attenuated through the application of their respective inhibitors.Distinct miRNAs selectively target various oncogenes,including NUAK Family Kinase 1(NUAK1),Snail Family Transcriptional Repressor 1(Snai1),Astrocyte elevated gene-1(AEG-1),Vimentin,Proliferation and apoptosis adaptor protein 15(PEA-15/PED),Hypoxia-inducible factor 1-alpha(HIF1),as well as tumor suppressor genes such as phosphatase and tensin homolog(PTEN),Suppressor of cytokine signaling 1(SOCS1),Tumor protein P53 binding protein 1(TP53BP1),and PH Domain and Leucine Rich Repeat Protein Phosphatase 2(PHLP22).This investigative approach proves invaluable in elucidating the specific miRNAs implicated in the deregulation of crucial genes pivotal to the pathogenesis of cancer.

IDENTIFICATION OF DIFFERENTIAL GENES IN OVARIAN CANCER USING REPRESENTATIONAL DIFFERENCE ANALYSIS OF cDNA

Objoctive To identify differential genes between normal ovarian epithelium tissue and ovarian epithelial cancer using representational difference analysis of cDNA （cDNA-RDA）. Methods cDNA-RDA was performed to identify the differentially expressed sequences between cDNAs from cancer tissue and cDNAs from normal ovarian tissue in the same patient who was in the early stage of ovarian serous cystadenocarcinoma. These differentially expressed fragments were cloned and analyzed, then sequenced and compared with known genes. Results Three differentially cxpressed cDNA fragments were isolated using cDNA from normal ovarian tissue as tester and cDNA from cancer tissue as driver amplicon by cDNA-RDA. DP Ⅲ- 1 and DP Ⅲ-2 cDNA clone showed significant homology to the cDNA of alpha actin gene; DPⅢ-3 cDNA clone showed significant homology to the cDNA oftransgelin gene. Conclusion cDNA-RDA can bc used to sensitively identify the differentially expressed genes in ovarian serous cystadenocarcinoma. Ovarian serous cystadenocarcinoma involves alteration of multiple genes.

Identification of differentially expressed genes in mouse hepatocarcinoma ascites cell line with low potential of lymphogenous metastasis

AIM: To identify genes differentially expressed in mouse hepatocarcinoma ascites cell line with low potential of lymphogenous metastasis. METHODS: A subtracted cDNA library of mouse hepatocarcinoma cell line with low potential of lympho- genous metastasis Hca-P and its synogenetic cell line Hca-F with high metastatic potential was constructed by suppression subtracted hybridization (SSH) method. The screened clones of the subtracted library were sequenced and GenBank homology search was performed. RESULTS: Fifteen differentially expressed cDNA fragments of Hca-P were obtained which revealed 8 known genes, 4 expressed sequence tags (ESTs) and 3 cDNAs showed no homology. CONCLUSION: Tumor metastasis is an incident involving multiple genes. SSH is a useful technique to detect differentially expressed genes and an effective method to clone novel genes.

RELATIONSHIP BETWEEN THE MUTATION OF P53 GENE AND INFILTRATION，METASTASIS AND PROGNOSIS OF GASTRIC CARCINOMA

gastric carcinomas were examined immunohistochemically with McAb to p53 protein in order to investigate the relationship between the expression of p53 protein and histological differentiation of gastric carcinoma, and to approach the mechanism of infiltration and metastasis of gastric carcinoma. The results showed that nuclear expression of p53 protein was significantly related to tumor size, depth of invasion, lymph node and liver metastases; but not related to histological differentiation. It is suggested that the accumulation of p53 protein was increased with the progression of gastric carcinoma, and therefore the cancer clone with p53 gene mutation may play an important role in the development of tumor invasion and metastasis.

A STUDY OF MULTI-GENE EXPRESSION IN THE HIGHLY METASTASIZING HUMAN OVARIAN CANCER CELL LINE HO-8910PM AND ITS MOTHER CELL LINE HO-8910

Objective: To investigate multi gene expression in the highly metastasizing human ovarian cancer cell line HO 8910PM and its mother cell line HO 8910. Method: The expression of 9 kinds of gene products in HO 8910PM and its mother cell line HO 8910 was detected by S P immunohistochemical method. Result: Eight kinds oncogene products showed various degrees of positive expression in both HO 8910PM and HO 8910 cell lines except gene bax. The expression of P53, Cyclin D 1, CD 44 ν6 and EGFR in HO 8910PM was stronger than that in HO 8910. However, the expression of P16, nm23 in HO 8910PM was weaker than that in HO 8910. There was no significant difference on the expression of C erb B 2 and bcl 2 between the two cell lines. Conclusion: Stronger invasive and metastatic patential is found in HO 8910PM than that in HO 8910. Carcinogenesis is a result of multi oncogene and multiple step process cooperation.

P16 GENE EXPRESSION IN OVARIAN EPITHELIAL CYSTADENOCARCINOMA

P16 gene expression was measured by immnohistochemical method in poor differentiated serous cystadenocarcinoma cell line, xenograft of highly metastasizing human ovarian carcinoma in nude mice and paramn embedded tissues from 69 patients with ovarian carcinoma. The result showed that P16 gene was positive expression in HO-8910 cell of mother line,HO8910PM cell line and xenograft of highly mcatstasizing human ovarian carcinoma in nude mice. However, P16gene in the metastatic cell had a weaker expression. P16gene positive expression were also found in sl cases of 69cases (73.9%) in the ovarian epithelial carcinoma paramn embedded tissues. Comparative studies showed that the positive rate of P16 gene expression markedly reduced with the increase of pathologic grade and clinical stage,metastasis in the lymph node and decrease of 5-year survival (P<0.05, p<0.01).P16 gene is not only a controller of cytokerastic cycle, but also a key member of tumorigenic suppresser:its absence and expression degree are also correlated with the ovarian carcinoma genesis and development,especially with the metastasis of the ovarian cancer.

Regulated Gene Expression with Promoters Responding to Inducers

Genetically engineered transgenic animals and plants have proven to be extremely useful for analyzing biochemical and developmental processes.Promoters responding to chemical inducers will be powerful tools for basic research in molecular biology and biotechnological applications.Various chemical inducible systems based on activation and inactivation of the target gene had been described.The transfer of regulatory elements from prokaryotes,insects,and mammals has opened new avenues to construct chemically inducible promoters that differ in their ability to regulate the temporal and spatial expression patterns,and this will dramatically increase the application of transgenic technology.This review provides an overview on regulation of gene expression,promoter activating systems,promoter inactivation systems,inducible gene over expression,and inducible anti suppression.

Human cancer genetics

The short report will be focused on the genetic basis and possible mechanisms of tumorigenesis, common types of cancer, the importance of genetic diagnosis of cancer, and the methodology of cancer genetic diagnosis. They will also review presymptomatic testing of hereditary cancers, and the application of expression profiling to identify patients likely to benefit from particular therapeutic approaches.

Experimental study on siRNA expressing vector-based RNA interference targeting c-Myc in human hepatocellular carcinoma cell line BEL-7402

Objective: To explore the inhibition of the expression of c-Myc in human hepatocellular carcinoma via vector-based RNA interference (RNAi). Methods: Two RNA interference DNA templates targeting c-Myc oncogene were designed via online software and synthesized. By ligation, the fragments were inserted into pSilencer 1.0-U6 to construct the recombinant siRNA expressing plasmids. The identified recombinants were introduced into BEL-7402 cells with Lipofactamine. The inhibition of c-Myc expression, together with the expression of CDK4, hTERT and Gadd45β in c-Myc down-regulated BEL-7402 cells, were analyzed by semi-quantitative RT-PCR. Results: Two recombinant plasmids pSic-myc-1 and pSic-myc-2, which direct the yields of siRNAs targeting c-Myc in cells, were constructed. Among which, pSic-myc-2 was shown to trigger a RNAi-mediated inhibition of expression of c-Myc in BEL-7402 by up to 90%. In c-Myc knockdown BEL-7402 cells, the expression of CDK4 and hTERT were down-regulated with a ratio of 85% and 57%, respectively, while the expression of Gadd45β was up-regulated by up to 110%. Conclusion: The expression of c-Myc in BEL-7402 could be suppressed by vector-based RNA interference successfully. The knockdown of c-Myc in turn resulted in the changes of expression of genes related to cell proliferation and apoptosis. Thus, our study provided a preliminary data in searching of a c-Myc-targeted RNAi therapy of human hepatocellular carcinoma.

Suppression subtractive hybridization for identifying differentially expressed genes in renal cell carcinoma

Objective To construct a renal cell carcinoma (RCC) cDNA subtractive library using suppression subtractive hybridization.Methods Polyadenylated RNA ［Poly (A)+ RNA］ was isolated from tissues of RCC and normal kidney, and single-strand cDNAs and double-strand cDNAs were synthesized in turn. RCC cDNAs were divided into two groups and ligated to the specific adaptors l and 2, and then hybridized with normal kidney cDNA twice with two rounds of suppression PCR. Second round PCR products were cloned to T/A plasmid vectors to set up the subtractive library. One hundred clones were randomly picked to perform enzyme digest analysis, and some underwent sequence analysis and Northern blot to identify RCC specifically expressed genes. SMART RACE procedure was operated to clone full length novel RCC specifically expressed genes.Results A human RCC subtractive library with high subtractive efficiency was successfully set up. The amplified library contains 350 positive clones. Random analysis of 100 clones with enzyme restriction showed that 85 plasmids in the clones contained 50-400?bp inserts. Sequence analysis was performed for 10 clones. All the 10 sequences were unknown before and derived from 6 unique, novel genes among which the cDNA insert RCC18 had five copies. Northern blot analysis showed that RCC18 cDNA was highly expressed in RCC, but no signal could be detected in normal kidney. Using SMART RACE technique, we obtained the full length of the novel gene RCC18.Conclusions The constructed cDNA subtractive library of human RCC is a highly efficient one and lays a solid foundation for large scale screening and cloning new and specific oncogenes or tumor suppressor genes of RCC. The novel specifically expressed genes provided an important clue for studying the mechanisms of occurrence and development of RCC.

GPS： a constraint-based gene position procurement in chromosome for solving large-scale multiobjective multiple knapsack problems

The multiple knapsack problem （MKP） forms a base for resolving many real-life problems. This has also been considered with multiple objectives in genetic algorithms （GAs） for proving its efficiency. GAs use self- adaptability to effectively solve complex problems with constraints, but in certain cases, self-adaptability fails by converging toward an infeasible region. This pitfall can be resolved by using different existing repairing techniques; however, this cannot assure convergence toward attaining the optimal solution. To overcome this issue, gene position-based suppression （GPS） has been modeled and embedded as a new phase in a classical GA. This phase works on the genes of a newly generated individual after the recombination phase to retain the solution vector within its feasible region and to im- prove the solution vector to attain the optimal solution. Genes holding the highest expressibility are reserved into a subset, as the best genes identified from the current individuals by re- placing the weaker genes from the subset. This subset is used by the next generated individual to improve the solution vec- tor and to retain the best genes of the individuals. Each gene＇s positional point and its genotype exposure for each region in an environment are used to fit the best unique genes. Further, suppression of expression in conflicting gene＇s relies on the requirement toward the level of exposure in the environment or in eliminating the duplicate genes from the environment.The MKP benchmark instances from the OR-library are taken for the experiment to test the new model. The outcome por- trays that GPS in a classical GA is superior in most of the cases compared to the other existing repairing techniques.

Construction of the subtractive cDNA library of injured adult and fetal rabbit skins

Objective: Early gestational mammalian fetuses possess the amazing ability to heal cutaneous wounds in a scarless fashion. Over the past years, scientists have been working to decipher the mechanisms underlying this regenerative repair. The remarkable phenotypic differences between fetal and adult healings behoves us to learn their characteristics in genetics, which represents potentially important mechanisms involved in wound repair observed in fetal versus adult tissues. In this sense, it is reasonable to construct subtractive cDNA library for future research. Methods: Middle laparotomy and hysterotomy were performed on pregnant rabbits at 20 day gestation to expose the fetal back, and a longitudinal incision through the skin was made on the back of the fetus. The traumatized fetal skin was harvested 12 hours post operation, the fetus control and traumatized adult skin specimens were taken at the same time. dscDNA was synthesized from total RNA of skin samples with SMART technology. Taking one of the three samples as Tester respectively and the other two as Drivers, we obtained 1 forward and 2 reverse hybridization products. After being amplified with selective polymerase chain reaction, the products were inserted into a vector, and then transferred into E.coli HB101. The colonies were screened afterwards. Results: The wounded fetuses were alive for a long time even after birth. Every determinant step, such as RNA isolation, cDNA synthesis, Rsa I digestion, adaptor ligation and hybridization, was well operated. Subtractive efficiency identification demonstrated that the suppression subtractive hybridization (SSH) was successful. Insertion into vector and transferring to E.coli were satisfactory. Conclusions: Instead of classic SSH, an improved SSH with 2 Drivers was applied for the experiment. Results confirmed that the improved program was reasonable and correct in both theory and practice. The subtractive cDNA library we have obtained is going to be used for future researches to reveal scarless healing related gene(s) and its (their) expression.