A Therapeutic DNA Vaccine Targeting HPV16 E7 in Combination with Anti-PD-1/PD-L1 Enhanced Tumor Regression and Cytotoxic Immune Responses.

Persistent infection of high-risk human papillomavirus (HPV) and the expression of E6 and E7 oncoproteins are the main causes of cervical cancer. Several prophylactic HPV vaccines are used in the clinic, but these vaccines have limited efficacy in patients already infected with HPV. Since HPV E7 is vital for tumor-specific immunity, developing a vaccine against HPV E7 is an attractive strategy for cervical cancer treatment. Here, we constructed an HPV16 E7 mutant that loses the ability to bind pRb while still eliciting a robust immune response. In order to build a therapeutic DNA vaccine, the E7 mutant was packaged in an adenovirus vector (Ad-E7) for efficient expression and enhanced immunogenicity of the vaccine. Our results showed that the Ad-E7 vaccine effectively inhibited tumor growth and increased the proportion of interferon-gamma (IFN-γ)-secreting CD8+ T cells in the spleen, and tumor-infiltrating lymphocytes in a mouse cervical cancer model was achieved by injecting with HPV16-E6/E7-expressing TC-1 cells subcutaneously. Combining the Ad-E7 vaccine with the PD-1/PD-L1 antibody blockade significantly improved the control of TC-1 tumors. Combination therapy elicited stronger cytotoxic T lymphocyte (CTL) responses, and IFN-γ secretion downregulated the proportion of Tregs and MDSCs significantly. The expressions of cancer-promoting factors, such as TNF-α, were also significantly down-regulated in the case of combination therapy. In addition, combination therapy inhibited the number of capillaries in tumor tissues and increased the thickness of the tumor capsule. Thus, Ad-E7 vaccination, in combination with an immune checkpoint blockade, may benefit patients with HPV16-associated cervical cancer.

[Corrigendum] SPAG9 expression is increased in human prostate cancer and promotes cell motility, invasion and angiogenesis in vitro.

Subsequently to the publication of the above article, an interested reader drew to the authors' attention that a pair of data panels presented in each of Figs. 3 and 4 appeared to be overlapping, such that these data may have been derived from the same original sources where they were intended to have shown the results from experiments performed under different experimental conditions. The authors realised that these figures had inadvertently been assembled incorrectly; however, as they had retained their access to the raw data, the authors were able to make the appropriate corrections required for these figures. The corrected versions of Figs. 3 and 4, showing the correct wound healing assay result for the DU1450­siSPAG9 experiment at 24 h in Fig. 3F and the correct Matrigel cell invasion assay result for PC3­siSPAG9 in Fig. 4C, are shown on the subsequent pages. Note that these errors did not adversely affect the major conclusions reported in the study. The authors all agree with these corrections and thank the Editor of Oncology Reports for allowing them the opportunity to publish this corrigendum. The authors also apologize for any inconvenience caused, and agree to address any additional questions regarding their results. All raw data are available from the authors upon request. [Oncology Reports 32: 2533­2540, 2014; DOI: 10.3892/or.2014.3539].

Rab31 promotes the invasion and metastasis of cervical cancer cells by inhibiting MAPK6 degradation.

Persistent infection with high-risk human papillomavirus (HPV) is the main risk factor for cervical cancer. Our mass spectrometry data showed that the Ras-associated binding protein Rab31 was upregulated by HPV; however, little is known regarding the role of Rab31 in the metastasis of cervical cancer cells. In this study, we showed that Rab31 was highly expressed in cervical cancer tissues and cells, and both HPV E6 and E7 promoted the expression of Rab31. Rab31 knockdown inhibited while Rab31 overexpression promoted the migration and invasion capabilities of cervical cancer cells. Additionally, Rab31 knockdown inhibited the epithelial-mesenchymal transition (EMT) and cytoskeletal rearrangement in cervical cancer cells. Furthermore, Rab31 interacted with mitogen-activated protein kinase 6 (MAPK6), and Rab31 knockdown inhibited the expression of MAPK6, which was mainly localized in the cytoplasm. More importantly, Rab31 knockdown promoted and Rab31 overexpression inhibited MAPK6 degradation. Accordingly, MAPK6 overexpression restored the decreased migration potential caused by Rab31 knockdown. Finally, a xenograft mouse model showed that Rab31 knockdown in cervical cancer cells led to reduced tumor growth and impaired lung and liver metastasis in vivo. In conclusion, Rab31 plays a crucial role in cervical cancer metastasis by inhibiting MAPK6 degradation. Thus, Rab31 may serve as a novel therapeutic target to manage cervical cancer.

Phosphorylation of RCC1 on Serine 11 Facilitates G1/S Transition in HPV E7-Expressing Cells.

Persistent infection of high-risk human papillomavirus (HR-HPV) plays a causal role in cervical cancer. Regulator of chromosome condensation 1 (RCC1) is a critical cell cycle regulator, which undergoes a few post-translational modifications including phosphorylation. Here, we showed that serine 11 (S11) of RCC1 was phosphorylated in HPV E7-expressing cells. However, S11 phosphorylation was not up-regulated by CDK1 in E7-expressing cells; instead, the PI3K/AKT/mTOR pathway promoted S11 phosphorylation. Knockdown of AKT or inhibition of the PI3K/AKT/mTOR pathway down-regulated phosphorylation of RCC1 S11. Furthermore, S11 phosphorylation occurred throughout the cell cycle, and reached its peak during the mitosis phase. Our previous data proved that RCC1 was necessary for the G1/S cell cycle progression, and in the present study we showed that the RCC1 mutant, in which S11 was mutated to alanine (S11A) to mimic non-phosphorylation status, lost the ability to facilitate G1/S transition in E7-expressing cells. Moreover, RCC1 S11 was phosphorylated by the PI3K/AKT/mTOR pathway in HPV-positive cervical cancer SiHa and HeLa cells. We conclude that S11 of RCC1 is phosphorylated by the PI3K/AKT/mTOR pathway and phosphorylation of RCC1 S11 facilitates the abrogation of G1 checkpoint in HPV E7-expressing cells. In short, our study explores a new role of RCC1 S11 phosphorylation in cell cycle regulation.

The Effects of Different Fluorescent Indicators in Observing the Changes of the Mitochondrial Membrane Potential during Oxidative Stress-Induced Mitochondrial Injury of Cardiac H9c2 Cells.

We evaluated the ability of different fluorescent indicators by various analytical instruments, including a laser scanning confocal microscope (LSCM), fluorescence plate reader, and flow cytometer (FCM), to measure the mitochondrial membrane potential (ΔΨm) of cardiac H9c2 cells during oxidative stress-induced mitochondrial injury. The mitochondrial oxygen consumption rate and a transmission electron microscope were used to detect changes in mitochondrial functions and morphology, respectively. Cardiac H9c2 cells were exposed to H2O2 (500, 750, 1000, and 1250 µM) to induce mitochondrial oxidative stress injury, and fluorescent indicators including tetramethyl rhodamine ethyl ester (TMRE), 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanine iodide (JC-1), and rhodamine 123 (R123) were used to detect changes in ΔΨm using an LSCM, fluorescence plate reader, and FCM. The decrease in ΔΨm caused by H2O2 was determined by endpoint and dynamic analyses after staining with JC-1 or TMRE. With the R123 probe, the LSCM could only detect the change in ΔΨm caused by 1000 µM H2O2. Moreover, R123 was less effective than JC-1 and TMRE for measurement of ΔΨm by the LSCM. Our data indicated that an LSCM is the most suitable instrument to detect dynamic changes in ΔΨm, whereas all three instruments can detect ΔΨm at the endpoint.

[Role of mitochondrial permeability transition pore in mediating the inhibitory effect of gastrodin on oxidative stress in cardiac myocytes in vitro].

OBJECTIVE: To explore the role of mitochondrial permeability transition pore (mPTP) in mediating the protective effect of gastrodin against oxidative stress damage in H9c2 cardiac myocytes. METHODS: H9c2 cardiac myocytes were treated with H2O2, gastrodin, gastrodin+H2O2, cyclosporin A (CsA), or CsA+gas+H2O2 group. MTT assay was used to detect the survival ratio of H9c2 cells, and flow cytometry with Annexin V-FITC/PI double staining was used to analyze the early apoptosis rate after the treatments. The concentration of ATP and level of reactive oxygen species (ROS) in the cells were detected using commercial kits. The mitochondrial membrane potential of the cells was detected with laser confocal microscopy. The expression of cytochrome C was detected with Western blotting, and the activity of caspase-3 was also assessed in the cells. RESULTS: Gastrodin pretreatment could prevent oxidative stress-induced reduction of mitochondrial membrane potential, and this effect was inhibited by the application of CsA. Gastrodin significantly lowered the levels of ROS and apoptosis-related factors in H2O2-exposed cells, and such effects were reversed by CsA. CsA significantly antagonized the protective effect of gastrodin against apoptosis in H2O2-exposed cells. CONCLUSIONS: Gastrodin prevents oxidative stress-induced injury in H9c2 cells by inhibiting mPTP opening to reduce the cell apoptosis.

Knockdown of ADAM17 inhibits cell proliferation and increases oxaliplatin sensitivity in HCT-8 colorectal cancer through EGFR-PI3K-AKT activation.

We investigated the role of a disintegrin and metalloproteinase 17 (ADAM17) in chemo resistance, and to clarify the mechanism underlying reverse of L-OHP resistance by knockdown of ADAM17. CRC tissues with corresponding adjacent normal tissues were collected. The mRNA and protein expression of ADAM17 in tissues were detected by RT-qPCR, immunohistochemistry and Western blot. The prognostic impact of ADAM17 expression were then validated in TCGA database to confirm the results. Resistance to oxaliplatin was induced in HCT-8 (HCT-8/L-OHP) colorectal cancer cell line by exposing cell to increasing concentrations of L-OHP. MTT were used to evaluate the resistance to L-OHP. Subsequently, Knockdown of ADAM17 in HCT-8 and HCT-8/L-OHP cells to explore the mechanism through which ADAM17 shRNA reverses L-OHP resistance. Our result showed that ADAM17 was higher expression in the cancerous tissue and related to the chemosensitivity. Moreover, ADAM17 shRNA, AG1478 and LY294002 could inhibit cell proliferation, induce apoptosis and increase oxaliplatin sensitivity in HCT-8/L-OHP and parental colorectal cancer cell line, but nonsense shRNA did not show this effect. Western blot analysis further confirmed that EGFR/PI3K/AKT signaling pathway is involved in ADAM17 shRNA inhibiting proliferation and chemosensitivity of HCT-8/L-OHP and HCT-8 cells. The present study provides the evidence that downregulation of ADAM17 could increase the sensitivity to chemotherapy, inhibit cell proliferation, induce apoptosis, and reverse oxaliplatin resistance via suppression of the EGFR/PI3K/AKT signaling pathway in CRC.

SPAG9 expression is increased in human prostate cancer and promotes cell motility, invasion and angiogenesis in vitro.

Sperm-associated antigen 9 (SPAG9) is a recently characterized oncoprotein involved in the progression of several human malignancies. To elucidate the role of SPAG9 in the development of human prostate cancer (PCa), tissue microarray (TMA) and immunohistochemistry were used to detect the clinical relevance of SPAG9 in PCa tissues. We found that SPAG9 expression was increased in the PCa tissues when compared with the level in the tumor adjacent normal prostate tissues, and increased SPAG9 staining was significantly correlated with TNM stage and tumor grade. We also examined prostate cancer cell motility, invasion and angiogenesis ability following reduced SPAG9 expression by siRNA. Our data showed that knockdown of SPAG9 in prostate cancer cell lines inhibited cell motility and invasion due to the inactivation of metalloproteinase-2 (MMP­2)/MMP-9 by upregulation of tissue inhibitor of metalloproteinase-1 (TIMP-1)/TIMP-2. Furthermore, downregulation of vascular endothelial growth factor (VEGF) secretion greatly contributed to the reduced ability of angiogenesis. Our data indicate that SPAG9 expression is significantly increased in PCa and it may be involved in the process of prostate cancer cell motility, migration and angiogenesis.