Bo-Kui Xiao

Effect of blocking VEGF, hTERT and Bcl-xl by multiple shRNA expression vectors on the human laryngeal squamous carcinoma xenograft in nude mice

In our previous work, we constructed short hairpin RNA (shRNA) expression plasmids that targeted human telomerase reverse transcriptase (hTERT) messenger RNA, and we demonstrated that these vectors could inhibit the growth of cancer cells by 76.5% in vivo. In order to maximize the efficiency and versatility of the vector-based siRNA approach, here we have constructed multiple shRNA expression vectors that simultaneously targeted 3 different genes in cancer cells, and then investigated their effect on human laryngeal squamous carcinoma (Hep-2) in vivo. Materials and methods Short hairpin RNA expression vectors targeting the mRNA of VEGF, hTERT and Bcl-xl were constructed and subsequently transfected by direct injections into the tumors formed by Hep-2 cells implanted in nude mice. The expression of targeted genes as well as apoptosis of tumor cells were evaluated after treatment with multiple shRNA vectors or control vectors. Results We found that expression of multiple shRNAs led to a significant reduction in VEGF, hTERT and Bcl-xl RNA and protein expression. Tumor growth curves showed that those tumors treated with the shRNAs were obviously smaller than control, non-transfected tumors. Analysis at 14 days following the final injection showed a tumor inhibition ratio of 91.2%. However, the control shRNA vectors showed none of these effects. Conclusions Our results demonstrate that the application of vector-based RNAi technology that involves blocking multiple targets will be a promising therapeutic modality in the gene therapy of human cancers. The data strongly suggest that simultaneously blocking multiple genes in human cancers using an RNAi approach should be considered in cancer therapy.

Application of combination of short hairpin RNA segments for silencing VEGF, TERT, and Bcl-xl expression in laryngeal squamous carcinoma

Objective To develop an RNA-interference (RNAi) approach involving the hitting of multiple targets by a recombinant plasmid and evaluate its antitumor effect on laryngeal squamous carcinoma in vitro and in vivo. Materials and methods A plasmid containing 3 different short hairpin RNA (shRNA) segments termed pEGFP-shVEGF-shTERT-shBcl-xl was constructed. Plasmids containing single shRNA against each target (VEFG, TERT, BCL-xl alone) individually were also constructed as control. Cells were treated with these plasmids. The expression of targeted genes as well as apoptosis of tumor cells were evaluated after treatment with multiple shRNA vectors or control vectors. The mRNA and protein expression were determined by RT-PCR and western blotting. Cell viability was examined using the MTT assay. Apoptotic morphological alterations were observed by Hoechst staining and electron microscopy. The in vivo antitumor effect was characterized in a nude mice model of laryngeal squamous carcinoma. Results. we demonstrated that a recombinant plasmid containing multiple shRNAs could effectively and simultaneously inhibit VEGF, TERT and Bcl-xl mRNA and protein expression in the HEp-2 cells; the plasmid containing the 3 different shRNAs exhibited a potent antitumor effect on LSCC both in vitro and in vivo, and could much more effectively induced cell apoptosis than each single shRNA.. We also demonstrated that the simultaneous blockage of these 3 genes have a better inhibitory effect on human HEp-2 cells than the blockage of each single shRNA. Conclusions Our study demonstrates that the application of vector-based RNAi technology that involves hitting multiple targets will be a promising therapeutic modality in the gene therapy of human laryngeal cancers; further, it provides experimental evidence for the clinical application of this technology in the future.

Protective effect of melatonin against gentamicin ototoxicity.

OBJECTIVE To research the protective effect of melatonin against gentamicin ototoxicity. METHODS Guinea pigs were randomly divided into four groups. The first group received intramuscular gentamicin (120 mg/kg body weight/day) for 17 days. Over the same time period, a second group simultaneously received intramuscular gentamicin (120 mg/kg body weight/day) plus (on the other side) intramuscular melatonin (0.3 ml kg body weight/day). Two groups of controls were treated for 17 days with either intramuscular melatonin or intramuscular saline. After the 17 days, each animal underwent distortion product otoacoustic emission testing (both ears). The guinea pigs were sacrificed by decapitation just after the final injection. Their cochleae were used to produce a tissue section, surface preparation and scanning electron microscope preparation. RESULTS Distortion product otoacoustic emission testing indicated gentamicin-induced hearing loss at 3, 4, 6 and 8 kHz in gentamicin-treated animals. Animals receiving melatonin co-therapy had significantly attenuated hearing loss and their cochleae showed lower rates of outer hair cell loss (comparing the same cochlear turns), compared with gentamicin-treated animals (p < 0.01). CONCLUSION These findings confirm the occurrence of outer hair cell loss after gentamicin treatment, and the attenuation of such loss following simultaneous melatonin injection, using the method of morphological evaluation. These results suggest that melatonin protects against gentamicin ototoxicity by interfering with cytotoxic mechanisms.

Alternative lengthening of telomeres in hTERT‐inhibited laryngeal cancer cells

In most human malignancies, telomere homeostasis is maintained by the reactivation of telomerase. While inhibiting telomerase provides a novel approach to the treatment of many cancers, telomere maintenance can occur in the absence of telomerase activity by the alternative lengthening of telomeres (ALT) mechanism. Therefore, it must be determined if inhibiting telomerase selects for cancer cells that activate ALT. Here, we report that Hep‐2 cells that survived anti‐telomerase treatments showed sustained proliferation in culture with down‐regulated human telomerase reverse transcriptase (hTERT) expression and significantly enhanced levels of ALT‐specific promyelocytic leukemia (PML) bodies. Analysis of the telomere lengthening kinetics also demonstrated elevated telomeric sister‐chromatid exchange (T‐SCE) in surviving Hep‐2 cells, consistent with their long and heterogeneous telomeres. Similar to ALT cells, the surviving cells showed evidence of ALT telomere homeostasis. Furthermore, proteomic analysis identified several proteins differentially expressed between the untreated Hep‐2 cells and surviving cells that may provide new insight for understanding these two telomere maintenance mechanisms. Thus, the findings in this study may help to improve telomerase‐based therapy for cancer. (Cancer Sci 2010)

Association between single nucleotide polymorphisms of surfactant protein D and allergic rhinitis in Chinese patients

The development of allergic rhinitis is considered to be determined by the interaction between genetic and environmental factors. Surfactant protein D (SP-D) has been proposed to offer protection against allergenic challenge at various levels in allergic responses. The present study aimed to investigate whether polymorphisms within the SFTPD gene (Met11Thr, Ala160Thr, and Ser270Thr) are associated with allergic rhinitis. Genotyping of SFTPD polymorphisms was performed using the pyrosequencing method. The study population comprised 216 patients with allergic rhinitis and 84 normal controls. The frequency of 11Thr/Thr genotype and Thr allele in the patient group was significantly higher than that in the control group after applying Bonferroni corrections (P = 0.007 and P = 0.006, respectively). Our subjects with the 11Thr/Thr genotype are more susceptible to allergic rhinitis. There were no significant differences between the patient group and the control group for frequencies of genotypes and alleles in either Ala160Thr or Ser270Thr single nucleotide polymorphisms (P > 0.05). No significant associations could be detected between any of these three SFTPD gene polymorphisms and the skin prick test response (P > 0.05). Meanwhile, there was a lack of association between the three loci and the levels of serum total immunoglobulin E (P > 0.05). In summary, our results suggest that the Met11Thr polymorphism in SP-D plays a major role in the genetic predisposition to allergic rhinitis in Chinese adult population, whereas the other two SP-D polymorphisms displayed no significant association with allergic rhinitis.

Indole-3-Carbinol Inhibits Nasopharyngeal Carcinoma Growth through Cell Cycle Arrest In Vivo and In Vitro

Nasopharyngeal carcinoma is a common malignant tumor in the head and neck. Because of frequent recurrence and distant metastasis which are the main causes of death, better treatment is needed. Indole-3-carbinol (I3C), a natural phytochemical found in the vegetables of the cruciferous family, shows anticancer effect through various signal pathways. I3C induces G1 arrest in NPC cell line with downregulation of cell cycle-related proteins, such as CDK4, CDK6, cyclin D1 and pRb. In vivo, nude mice receiving I3C protectively or therapeutically exhibited smaller tumors than control group after they were inoculated with nasopharyngeal carcinoma cells. The expression of CDK4, CDK6, cyclin D1 and pRb in preventive treatment group and drug treatment group both decreased compared with the control group. We conclude that I3C can inhibit the growth of NPC in vitro and in vivo by suppressing the expression of CDK and cyclin families. The drug was safe and had no toxic effects on normal tissues and organs.

Targeted therapy of human laryngeal squamous cell carcinoma in vitro by antisense oligonucleotides directed against telomerase reverse transcriptase mRNA

A number of different approaches have been developed to inhibit telomerase activity in human cancer cells. In this study, the effect of antisense oligonucleotides (ODNs) by targeting human telomerase reverse transcriptase (hTERT) mRNA in a laryngeal cancer cell line (Hep-2) was investigated. A 20mer antisense oligodeoxynucleotide targeting the most open part of hTERT mRNA (anti-hTERT) and a mismatched control sequence were synthesized. Cells were treated daily with oligonucleotides for up to 72 hours. hTERT mRNA expression was measured by the reverse transcription polymerase chain reaction (RT-PCR) assay; telomerase activity by the telomerase PCR ELISA assay kit (TRAP; Boehringer Mannheim, GmbH, Mannheim, Germany). Cell viability after administration of ODNs was determined using the MTT assay. Morphological changes were examined by haematoxylin and eosin staining. The cell cycle was analyzed using flow cytometry. It was found that antisense treatment induced a decrease in hTERT mRNA expression, telomerase activity, cell growth rate, cell viability, and an increase in apoptosis. The results suggest that inhibition of telomerase activity in Hep-2 cells by short-term antisense treatment against the mRNA of hTERT results in apoptotic cell death. The treatment with anti-hTERT may be useful as a treatment modality for laryngeal squamous carcinoma.

Interleukin-23 Facilitates Thyroid Cancer Cell Migration and Invasion by Inhibiting SOCS4 Expression via MicroRNA-25.

Interleukin–23 (IL–23) is a conventional proinflammatory cytokine that plays a role in tumor progression by inducing inflammation in the tumor microenvironment. However, the role of IL–23 in thyroid cancer migration and invasion remains unclear. In the present study, we observed that the treatment with IL–23, induced migration and invasion in human thyroid cancer cells. Additional data demonstrate that SOCS4 negatively regulates IL-23-mediated migration and invasion. On investigating the mechanisms involved in IL–23 mediated migration and invasion, we observed that miR–25 promotes the migration and invasion of thyroid cancer cells by directly binding to the 3′-UTR of SOCS4 that leads to the inhibition of SOCS4. In addition, we also demonstrated that IL–23 increases miR–25 expression levels, and overexpressed miR–25 is involved in IL-23-associated SOCS4 inhibition and cell migration and invasion. Together, our data suggest that IL–23 induces migration and invasion in thyroid cancer cells by mediating the miR–25/SOCS4 signaling pathway.

Effect of RNA interference targeting human telomerase reverse transcriptase on telomerase and its related protein expression in nasopharyngeal carcinoma cells.

OBJECTIVE Analysis of the correlation between telomerase and the expression of its related proteins may provide insight into the molecular mechanism of nasopharyngeal carcinogenesis. We investigated the effect of short hair pin ribonucleic acid (RNA) specific for human telomerase reverse transcriptase messenger RNA on the expression of the proteins c-myc (the transcription factor c-myc is a shortlived nuclear phospho-protein involved in cell proliferation and differentiation, belongs to the myc family), proliferating cell nuclear antigen and Caspase-3 in nasopharyngeal carcinoma cells. METHODS Short hairpin RNA expression vectors targeting the messenger RNA of human telomerase reverse transcriptase were constructed. Cells were treated with the short hairpin RNA expression vectors targeting human telomerase reverse transcriptase or vectors that included mismatched short hairpin RNA, and telomerase activity was measured by telomeric repeat amplification enzyme-linked immunosorbent assay. Cell viability was examined using the 3-(4,5-dimethyl thizol-2-yl) 2,5-diphenyl tetrazolium bromide assay. The expression of the three proteins (c-myc, proliferating cell nuclear antigen and Caspase-3) was determined by Western blotting. RESULTS Short hairpin RNA specific for human telomerase reverse transcriptase messenger RNA significantly inhibited telomerase activity. In addition, the expression of and proliferating cell nuclear antigen were both inhibited, while the expression of Caspase-3 was up-regulated. CONCLUSIONS Our results suggest that short hairpin RNA directed against human telomerase reverse transcriptase inhibits cell viability by regulating telomerase activity and its related proteins expression in nasopharyngeal carcinoma cells. Therefore, RNA interference technology may be a promising strategy for the treatment of nasopharyngeal cancer.

Inhibition of Telomerase Activity in Cancer Cells using Short Hairpin RNA Expression Vectors

Telomerase activity is mainly regulated by the human telomerase reverse transcriptase (hTERT) gene. Our objective was to investigate the effect of short hairpin RNA (shRNA) directed against hTERT mRNA on telomerase activity in laryngeal cancer cells (Hep-2), nasopharyngeal carcinoma cells (NEC), and human bone marrow mesenchyme stem cells (hMSCs). Short hairpin RNA expression vectors targeting the messenger RNA of hTERT were constructed. Cells were treated with shRNA expression vectors directed against hTERT mRNA and control vectors that included mismatched shRNA. We found that treatment of special shRNA expression vectors induced significantly decrease in hTERT expression, telomerase activity, and cell viability in Hep-2 and NEC cells. In contrast, the shRNA control showed none of these effects. And none of these effects appeared in hMSCs cells. Our results suggest that shRNA against hTERT mRNA inhibits telomerase activity and cell viability through suppression of the hTERT expression in cancer cells. And this treatment has no side effect on healthy cells lack of telomerase activity. RNA interfering technology may be a promising strategy for the treatment of cancers.