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HIV-1 Nef and KSHV oncogene K1 synergistically promote angiogenesis by inducing cellular miR-718 to regulate the PTEN/AKT/mTOR signaling pathway.

Xue M, Yao S, Hu M, Li W, Hao T, Zhou F, Zhu X, Lu H, Qin D, Yan Q, Zhu J, Gao SJ, Lu C - Nucleic Acids Res. (2014)

Bottom Line: Kaposi's sarcoma (KS) is an AIDS-defining cancer with aberrant neovascularization caused by KS-associated herpesvirus (KSHV).Furthermore, Nef and K1 induced cellular miR-718, which inhibited PTEN expression by directly targeting a seed sequence in the 3' UTR of its mRNA.Our results demonstrate an essential role of miR-718/AKT/mTOR axis in AIDS-KS and thus may represent an attractive therapeutic target.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, P.R. China Key Laboratory of Pathogen Biology of Jiangsu Province, Nanjing Medical University, Nanjing, P.R. China Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China Department of Physiology, Xuzhou Medical College, Xuzhou, Jiangsu 221004, P.R. China.

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PTEN/AKT/mTOR pathway mediates K1- and Nef-induced tumorigenesis in nude mice. (A) Western blot analysis of total PTEN and phosphorylation levels of PI3K, AKT and mTOR in tumor tissues from nude mice induced by EA.hy926 cells transduced with K1, Nef or both. Numbers labeled under the bands were the relative intensities of the bands after calibrating for loading with the house-keeping protein or their nonphosphorylated proteins. The relative value of proteins in the Mock group was considered as ‘1’. (B) PTEN inhibits Nef promotion of K1-induced tumorigenesis. EA.hy926 cells transduced with K1, Nef or both were transfected with pPTEN or the control plasmid and inoculated into nude mice to induce tumors. The mice were daily monitored for the appearance of tumors until 58 days. Tumor size was estimated by two-dimensional caliper measurement. Data represent mean ± SD, each group with five tumors (n = 5). Two independent experiments were performed and similar results were obtained. (C) PTEN inhibits Nef promotion of K1-induced tumorigenesis indicated by tumor's weight. The tumors from nude mice treated as in (B) were removed and weighed. Scatter plots represent the weight of independent tumors from different groups. Data represent mean ± SD, each group with five tumors (n = 5). Two independent experiments were performed and similar results were obtained. (D) Activation of mTOR signals is required for Nef promotion of K1-induced tumorigenesis indicated by tumor size. EA.hy926 cells transduced with K1 and Nef were injected (s.c.) into the left flanks of mice for xenograft formation. The mice received the treatments by intraperitoneal injection of rapamycin. The results are expressed as the mean ± SD, each group with five tumors (n = 5). Two independent experiments were performed and similar results were obtained. (E) Activation of mTOR signals is required for Nef promotion of K1-induced tumorigenesis indicated by tumor weight. The tumors from nude mice treated as in (D) were removed and weighed. Scatter plots represent the weight of independent tumors from different groups. Data reflect the mean ± SD. Data represent mean ± SD, each group with five tumors (n = 5). Two independent experiments were performed and similar results were obtained.
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Figure 5: PTEN/AKT/mTOR pathway mediates K1- and Nef-induced tumorigenesis in nude mice. (A) Western blot analysis of total PTEN and phosphorylation levels of PI3K, AKT and mTOR in tumor tissues from nude mice induced by EA.hy926 cells transduced with K1, Nef or both. Numbers labeled under the bands were the relative intensities of the bands after calibrating for loading with the house-keeping protein or their nonphosphorylated proteins. The relative value of proteins in the Mock group was considered as ‘1’. (B) PTEN inhibits Nef promotion of K1-induced tumorigenesis. EA.hy926 cells transduced with K1, Nef or both were transfected with pPTEN or the control plasmid and inoculated into nude mice to induce tumors. The mice were daily monitored for the appearance of tumors until 58 days. Tumor size was estimated by two-dimensional caliper measurement. Data represent mean ± SD, each group with five tumors (n = 5). Two independent experiments were performed and similar results were obtained. (C) PTEN inhibits Nef promotion of K1-induced tumorigenesis indicated by tumor's weight. The tumors from nude mice treated as in (B) were removed and weighed. Scatter plots represent the weight of independent tumors from different groups. Data represent mean ± SD, each group with five tumors (n = 5). Two independent experiments were performed and similar results were obtained. (D) Activation of mTOR signals is required for Nef promotion of K1-induced tumorigenesis indicated by tumor size. EA.hy926 cells transduced with K1 and Nef were injected (s.c.) into the left flanks of mice for xenograft formation. The mice received the treatments by intraperitoneal injection of rapamycin. The results are expressed as the mean ± SD, each group with five tumors (n = 5). Two independent experiments were performed and similar results were obtained. (E) Activation of mTOR signals is required for Nef promotion of K1-induced tumorigenesis indicated by tumor weight. The tumors from nude mice treated as in (D) were removed and weighed. Scatter plots represent the weight of independent tumors from different groups. Data reflect the mean ± SD. Data represent mean ± SD, each group with five tumors (n = 5). Two independent experiments were performed and similar results were obtained.

Mentions: The tumors were further used to determine whether PTEN/AKT/mTOR pathway was involved in the synergistic effect of Nef and K1 on tumorigenesis in vivo. As shown in Figure 5A, the phosphorylated forms of PI3K, AKT and mTOR were increased in tumors induced by K1 or Nef, which were even more striking in tumors induced by both K1 and Nef, whereas the levels of total PTEN were reduced accordingly. We transfected the K1- and Nef-expressing EA.hy926 cells with pPTEN and subsequently injected them into nude mice. As shown in Figure 5B and C, expression of pPTEN inhibited the growth of tumors induced by K1, Nef or both. Similarly, treatment with rapamycin effectively suppressed the growth of tumors induced by K1, Nef or both (Figure 5D and E).


HIV-1 Nef and KSHV oncogene K1 synergistically promote angiogenesis by inducing cellular miR-718 to regulate the PTEN/AKT/mTOR signaling pathway.

Xue M, Yao S, Hu M, Li W, Hao T, Zhou F, Zhu X, Lu H, Qin D, Yan Q, Zhu J, Gao SJ, Lu C - Nucleic Acids Res. (2014)

PTEN/AKT/mTOR pathway mediates K1- and Nef-induced tumorigenesis in nude mice. (A) Western blot analysis of total PTEN and phosphorylation levels of PI3K, AKT and mTOR in tumor tissues from nude mice induced by EA.hy926 cells transduced with K1, Nef or both. Numbers labeled under the bands were the relative intensities of the bands after calibrating for loading with the house-keeping protein or their nonphosphorylated proteins. The relative value of proteins in the Mock group was considered as ‘1’. (B) PTEN inhibits Nef promotion of K1-induced tumorigenesis. EA.hy926 cells transduced with K1, Nef or both were transfected with pPTEN or the control plasmid and inoculated into nude mice to induce tumors. The mice were daily monitored for the appearance of tumors until 58 days. Tumor size was estimated by two-dimensional caliper measurement. Data represent mean ± SD, each group with five tumors (n = 5). Two independent experiments were performed and similar results were obtained. (C) PTEN inhibits Nef promotion of K1-induced tumorigenesis indicated by tumor's weight. The tumors from nude mice treated as in (B) were removed and weighed. Scatter plots represent the weight of independent tumors from different groups. Data represent mean ± SD, each group with five tumors (n = 5). Two independent experiments were performed and similar results were obtained. (D) Activation of mTOR signals is required for Nef promotion of K1-induced tumorigenesis indicated by tumor size. EA.hy926 cells transduced with K1 and Nef were injected (s.c.) into the left flanks of mice for xenograft formation. The mice received the treatments by intraperitoneal injection of rapamycin. The results are expressed as the mean ± SD, each group with five tumors (n = 5). Two independent experiments were performed and similar results were obtained. (E) Activation of mTOR signals is required for Nef promotion of K1-induced tumorigenesis indicated by tumor weight. The tumors from nude mice treated as in (D) were removed and weighed. Scatter plots represent the weight of independent tumors from different groups. Data reflect the mean ± SD. Data represent mean ± SD, each group with five tumors (n = 5). Two independent experiments were performed and similar results were obtained.
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Related In: Results  -  Collection

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Figure 5: PTEN/AKT/mTOR pathway mediates K1- and Nef-induced tumorigenesis in nude mice. (A) Western blot analysis of total PTEN and phosphorylation levels of PI3K, AKT and mTOR in tumor tissues from nude mice induced by EA.hy926 cells transduced with K1, Nef or both. Numbers labeled under the bands were the relative intensities of the bands after calibrating for loading with the house-keeping protein or their nonphosphorylated proteins. The relative value of proteins in the Mock group was considered as ‘1’. (B) PTEN inhibits Nef promotion of K1-induced tumorigenesis. EA.hy926 cells transduced with K1, Nef or both were transfected with pPTEN or the control plasmid and inoculated into nude mice to induce tumors. The mice were daily monitored for the appearance of tumors until 58 days. Tumor size was estimated by two-dimensional caliper measurement. Data represent mean ± SD, each group with five tumors (n = 5). Two independent experiments were performed and similar results were obtained. (C) PTEN inhibits Nef promotion of K1-induced tumorigenesis indicated by tumor's weight. The tumors from nude mice treated as in (B) were removed and weighed. Scatter plots represent the weight of independent tumors from different groups. Data represent mean ± SD, each group with five tumors (n = 5). Two independent experiments were performed and similar results were obtained. (D) Activation of mTOR signals is required for Nef promotion of K1-induced tumorigenesis indicated by tumor size. EA.hy926 cells transduced with K1 and Nef were injected (s.c.) into the left flanks of mice for xenograft formation. The mice received the treatments by intraperitoneal injection of rapamycin. The results are expressed as the mean ± SD, each group with five tumors (n = 5). Two independent experiments were performed and similar results were obtained. (E) Activation of mTOR signals is required for Nef promotion of K1-induced tumorigenesis indicated by tumor weight. The tumors from nude mice treated as in (D) were removed and weighed. Scatter plots represent the weight of independent tumors from different groups. Data reflect the mean ± SD. Data represent mean ± SD, each group with five tumors (n = 5). Two independent experiments were performed and similar results were obtained.
Mentions: The tumors were further used to determine whether PTEN/AKT/mTOR pathway was involved in the synergistic effect of Nef and K1 on tumorigenesis in vivo. As shown in Figure 5A, the phosphorylated forms of PI3K, AKT and mTOR were increased in tumors induced by K1 or Nef, which were even more striking in tumors induced by both K1 and Nef, whereas the levels of total PTEN were reduced accordingly. We transfected the K1- and Nef-expressing EA.hy926 cells with pPTEN and subsequently injected them into nude mice. As shown in Figure 5B and C, expression of pPTEN inhibited the growth of tumors induced by K1, Nef or both. Similarly, treatment with rapamycin effectively suppressed the growth of tumors induced by K1, Nef or both (Figure 5D and E).

Bottom Line: Kaposi's sarcoma (KS) is an AIDS-defining cancer with aberrant neovascularization caused by KS-associated herpesvirus (KSHV).Furthermore, Nef and K1 induced cellular miR-718, which inhibited PTEN expression by directly targeting a seed sequence in the 3' UTR of its mRNA.Our results demonstrate an essential role of miR-718/AKT/mTOR axis in AIDS-KS and thus may represent an attractive therapeutic target.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, P.R. China Key Laboratory of Pathogen Biology of Jiangsu Province, Nanjing Medical University, Nanjing, P.R. China Department of Microbiology, Nanjing Medical University, Nanjing 210029, P.R. China Department of Physiology, Xuzhou Medical College, Xuzhou, Jiangsu 221004, P.R. China.

Show MeSH
Related in: MedlinePlus