Oncogenesis In Various Types Research Articles

E2F is required for STAT3-mediated upregulation of cyclin B1 and Cdc2 expressions and contributes to G2-M phase transition.

Activation of transcription factor STAT3 is involved in cell proliferation, differentiation, and cell survival. Constitutive activation of STAT3 pathway has been associated with the oncogenesis of various types of cancers. It has been reported that STAT3 plays a key role in the G1 to S phase cell cycle transition induced by the cytokine receptor subunit gp130, through the upregulation of cyclins D1, D2, D3, A, and Cdc25A and the concomitant downregulation of p21 and p27. However, its role in mediating G2-M phase transition has not been studied. The cyclin B1/Cdc2 complex is widely accepted as the trigger of mitosis in all organisms and is believed to be necessary for progression through S phase and keep active during the G2-M transition and progression. In the present study, we found that activation of STAT3 stimulates cyclin B1 and Cdc2 expressions. Deletion and site-directed mutations on cyclin B1 and Cdc2 promoters indicated that E2F element mediates the upregulation of these two promoters in a STAT3-dependent manner. The findings reported here demonstrated that STAT3 participates in modulating G2-M phase checkpoint by regulating gene expressions of cyclin B1 and Cdc2 via E2F.

RPN11 deubiquitinase promotes proliferation and migration of breast cancer cells.

The deubiquitinase enzyme RPN11 is involved in oncogenesis in various types of cancer. However, in breast cancer, the expression levels, prognostic relevance and biological function of RPN11 remains unclear. In the present study, RPN11 expression levels in breast cancer tissues and adjacent non‑tumor tissues were determined by reverse transcription‑quantitative polymerase chain reaction and immunohistochemical staining, and the association of RPN11 with clinicopathological features of breast cancer was evaluated. RPN11 expression was upregulated in breast cancer tissues compared with healthy tissues. Additionally, high expression levels of RPN11 may be an indicator of poor prognosis, as validated by a breast cancer cohort from the Gene Expression Omnibus database. Knockdown of RPN11 in MDA‑MB‑231 and T47D cells significantly reduced cell proliferation and enhanced G0/G1 arrest and apoptosis. Exogenous overexpression of RPN11 in MCF7 and Hs578T cells promoted cell growth and inhibited apoptosis. In addition, knockdown of RPN11 abrogated cell migration and reduced epithelial‑mesenchymal transition. In conclusion, these findings suggested that RPN11 may function as an oncogene and its upregulation in breast cancer suggests that it may be a therapeutic target.

117. Development of Novel Cancer Therapy Combination of Ad-SOCS Gene Therapy and LAK Cell Immunotherapy for the Treatment of Prostate Cancer

Background Suppressor of cytokine signaling 3 (SOCS3) is a promising molecule for cancer gene therapy. SOCS3 suppresses tumor growth through inhibition of mutiple signaling pathways including Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3), extracellular signal-regulated kinase (ERK), and focal adhesion kinase (FAK). The constitutive activation of JAK/STAT3 pathway is known to be involved in oncogenesis of various types of cancers including prostate cancer. We investigated the anti-tumor activity of Ad-SOCS, which is the recombinant adenovirus vectors carrying the SOCS3 gene, against prostate cancer cell line in vitro. Furthermore, to improve the antitumor effect against prostate cancer, we combined LAK (Lymphokine activated killer) cell immunotherapy with Ad-SOCS gene therapy. Materials and Methods LNCaP, human prostate cancer cell line was used in this study. The cytotoxicity of Ad-SOCS against LNCaP was measured by XTT assay. LAK cells were generated from PBMCs isolated from fresh blood by Ficoll-paque (GE Healthcare, Munich, Germany) density gradient centrifugation. PBMC were incubated in medium with interleukin (IL)-2 and anti CD3 antibody (OKT3) to generate LAK cells. The cytotoxicity of LAK cells against LNCaP cells infected with Ad-SOCS was investigated by the in vitro cytotoxicity assay. Expression level of SOCS3, STAT3 and ULBPs were measured by real-time PCR. Results Ad-SOCS showed the significantly higher cell growth inhibitory effect compared to Ad-LacZ and PBS controls in LNCaP cells. In real-time PCR, Ad-SOCS significantly increased the level of SOCS3 mRNA expression. Sequentially, the expression of STAT3 mRNA was decreased by Ad-SOCS infection. Upregulation of SOCS3 mRNA and downregulation of STAT3 mRNA were not observed in both Ad-LacZ and PBS infected LNCaP cells. In cytotoxicity assay, LAK cells exhibited the significantly higher cytotoxicity against LNCaP cells infected with Ad-SOCS at all effector: target cell ratios, 1:1,5:1, 10:1, compared with that of non-infected or Ad-LacZ infected cells. The mRNA expression levels of ULBP 1-5, which are NKG2D ligands to stimulate LAK cell activities, were measured and the mRNA expressions of ULBP 1, 3 and 4, in LNCaP infected with Ad-SOCS were significantly increased compared to the treatments. Conclusion In the present study, we demonstrated that Ad-SOCS could inhibit the cell growth of LNCaP cells and increased the sensitivity of LAK cell in vitro. These findings suggested that the Ad-SOCS and LAK cell combination therapy warranted the further development of novel therapeutic approach for advanced prostate cancer.

Fra-1 is upregulated in lung cancer tissues and inhibits the apoptosis of lung cancer cells by the P53 signaling pathway.

Fos-related antigen-1 (Fra-1) is a member of the activator protein-1 transcription factor superfamily. It plays important roles in oncogenesis in various types of malignancies. Herein, we investigated the expression of Fra-1 in lung cancer tissues by qPCR, immunohistochemistry, and western blot technologies. The results showed that Fra-1 was overexpressed in the lung cancer tissues when compared with the level in the adjacent non-cancerous tissues. To explore the possible mechanism of Fra-1 in lung cancer, we elucidated the effect of Fra-1 on the apoptosis of lung cancer H460 cells, and found that the rate of cell apoptosis was decreased in the H460/Fra-1 cells compared with the H460 or H460/vector cells. Cell apoptosis is closely related with a reduction in mitochondrial membrane potential (ΔΨm) and an increase in intracellular reactive oxygen species (ROS) and calcium ion (Ca2+) concentrations. Our results showed that overexpression of Fra-1 in the lung cancer H460 cells, led to an increase in ΔΨm and and a decrease in intracellular ROS and Ca2+ concentrations. Furthermore, we found that Fra-1 was correlated with dysregulation of the P53 signaling pathway in lung cancer tissues in vitro. At the same time, we found that Fra-1 overexpression affected the expression of MDM2 and P53 in vivo. In summary, our results suggest that Fra-1 is upregulated in lung cancer tissues and functions by affecting the P53 signaling pathway in lung cancer.

CD90 is upregulated in gastric cancer tissues and inhibits gastric cancer cell apoptosis by modulating the expression level of SPARC protein.

Cluster of differentiation90 (CD90) (Thy-1) plays important roles in the oncogenesis in various types of malignancies. In the present study, we investigated the expression of CD90 in gastric cancer (GC) tissues by q-PCR, immunohistochemistry (IHC), and western blot technologies. The results showed that CD90 was overexpressed in gastric cancer tissues compared with the level in the adjacent non‑cancerous tissues. To explore the possible mechanism of CD90 in GC, we elucidated the effect of CD90 on the apoptosis of AGS gastric cancer cells, and found that a considerable decrease in apoptotic cells was observed for AGS cells with CD90 overexpression. Meanwhile, the rate of apoptotic cells was increased in the AGS cells with CD90 interference (siCD90) compared with that in the AGS cells. Cell apoptosis is closely related to a reduction in mitochondrial membrane potential (ΔΨm) and an increase in intracellular reactive oxygen species (ROS) and calcium ion(Ca2+) concentrations. Our results showed that overexpression of CD90 in the AGS gastric cancer cells led to an increase in ΔΨm and a decrease in intracellular ROS and Ca2+ concentrations. At the same time, siCD90 reduced ΔΨm and the increase in intracellular ROS and Ca2+ concentrations. Furthermore, we identified and confirmed that CD90 functions by modulating the expression level of secreted protein, acidic, cysteine‑rich (osteonectin)(SPARC) invitro through LC‑MS/MS analyses and western blot technology. In summary, our results suggest that CD90 is upregulated in gastric cancer and inhibits gastric cancer cell apoptosis by modulating the expression level of SPARC protein.

Cyclin D1 protein expression in lung cancer.

Cyclin D1, a G1 cyclin, has been implicated in the oncogenesis of various types of malignancies via deregulation of cell cycles. Amplification of cyclin D1 as a part of 11q13 amplicon has been reported in lung cancer as well as a subset of carcinomas arising from various organs including breast, head and neck, and esophagus. In addition to its role as an oncogene, several recent studies have suggested that amplification is indicative of poor prognosis. In this study we examined the cyclin D1 protein expression in 102 consecutive cases of lung cancers using the microwave enhanced immunohistochemical staining method and correlated the data with the histologic subtype and grade, Ki-67 (MIB-1) labeling index, and survival. Nuclear positive staining was observed in 18 cases (18 %) of lung cancers. Although squamous cell carcinoma demonstrated a higher rate of expression (12 /58, 21%), three of 33 adenocarcinomas (9%) revealed overexpression and both adenocarcinoma and squamous cell carcinoma components within the adenosquamous carcinoma showed nuclear staining. There was no correlation between cyclin D1 overexpression and histologic grade, Ki-67 (MIB-1) labeling index, and survival. These observations indicate that cyclin D1 protein overexpression might be implicated in the oncogenesis of the various histologic types of non-small cell lung carcinomas but it has no usefulness as a prognostic marker.