Human endogenous retrovirus type K (HERV-K) Env protein was previously demonstrated to be overexpressed in human breast cancer (BC) cells and tissues. However, the molecular pathways driving the specific alterations are unknown. We now show that knockdown of its expression with an shRNA (shRNAenv) blocked BC cell proliferation, migration, and invasion. shRNAenv transduction also attenuated the ability of BC cells to form tumors, and notably prevented metastasis. Mechanistically, downregulation of HERV-K blocked expression of tumor-associated genes that included Ras, p-RSK, and p-ERK. The major upstream regulators influenced by HERV-K knockdown were p53, TGF- β1, and MYC. Of interest, when the HERV-K env gene was overexpressed in shRNAenv-transduced BC cells using an HERV-K env expression vector, Ras/Raf/MEK/ERK pathway signaling was restored. CDK5, which alters p53 phosphorylation in some cancers, was upregulated and p53 was downregulated when HERV-K was overexpressed. CDK5 is also a mediator of TGF-β1-induced epithelial-mesenchymal transition and migration in cancer cells, and is involved in tumor formation. Importantly, reductions in migration, invasion, and transformation of BC cells stably transduced with shRNAenv was reversed after adding back a vector with a synonymous mutation of HERV-K env. Taken together, these results indicate that HERV-K Env protein plays an important role in tumorigenesis and metastasis of BC.

We have previously reported that human endogenous retrovirus-K (HERV-K) envelope () protein is a tumor-associated antigen (TAA) for cancer vaccines, and that its antibodies (mAbs) possess antitumor activity against cancer. In this study, a chimeric antigen receptor (CAR) specific for HERV-K env protein (K-CAR) was generated using anti-HERV-K mAb. K-CAR T cells from peripheral blood mononuclear cells (PBMCs) of 9 breast cancer (BC) patients and 12 normal donors were able to inhibit growth of, and to exhibit significant cytotoxicity toward, BC cells but not MCF-10A normal breast cells. The antitumor effects in cancer cells were significantly reduced when control T cells were used, or the expression of HERV-K was knocked down by an shRNA. Secretion of multiple cytokines, including IFNγ, TNF-α, and IL-2, was significantly enhanced in culture media of BC cells treated with K-CARs. Significantly reduced tumor growth and tumor weight was observed in xenograft models bearing MDA-MB-231 or MDA-MB-435.eB1 BC cells. Importantly, the K-CAR prevented tumor metastasis to other organs. Furthermore, downregulation of HERV-K expression in tumors of mice treated with K-CAR correlated with upregulation of p53 and downregulation of MDM2 and p-ERK. Importantly, the expression of HERV-K env protein in metastatic tumor tissues treated with K-CAR T cells correlated with the expression of Ras. Our results indicate that HERV-K env protein is an oncoprotein and may play an important role in tumorigenesis related to p53 and Ras signaling pathways. Anti-HERV-K treatment, including K-CAR treatment, shows potential for immunotherapy of BC.

Triple-negative breast cancer (TNBC) is an aggressive subgroup of breast cancer lack of effective target therapy. This study was to investigate the prognostic role of p53 and Ki-67 in 156 cases of TNBC patients. Logistic regression analysis was used to examine the association between clinical parameters and recurrence. Univariate and multivariate analyses were used to examine the association between clinical characteristics and disease-free survival (DFS) or overall survival (OS). Survival analyses using the Kaplan-Meier method were performed to examine the association between p53/Ki-67 and DFS and OS. Our data showed that p53 was positive in 71.3% and the Ki-67 high index was in 82.8% of TNBC. Elevated p53 and Ki-67 were associated with histological grade. The tumor size, lymph node involvement, and p53 expression are associated with risk of recurrence. Tumor size, lymph node involvement, family history, Ki-67 and p53 are independent variables associated with either DFS or OS. TNBC patients with positive p53 or Ki-67 high index or family history of cancer have a significant association with worse prognosis. This study suggests that p53, Ki-67 and family history are useful prognostic markers in TNBC.

Cancer stem cell theory indicates cancer stem cells are the key to promote tumor invasion and metastasis. Studies showed that BMI-1 could promote self-renew, differentiation and tumor formation of CSCs and invasion/metastasis of human cancer. However, whether BMI-1 could regulate invasion and metastasis ability of CSCs is still unclear. In our study, we found that up-regulated expression of BMI-1 was associated with tumor invasion, metastasis and poor survival of pancreatic cancer patients. CD133+ cells were obtained by using magnetic cell sorting and identified of CSCs properties such as self-renew, multi-differentiation and tumor formation ability. Then, we found that BMI-1 expression was up-regulated in pancreatic cancer stem cells. Knockdown of BMI-1 expression attenuated invasion ability of pancreatic cancer stem cells in Transwell system and liver metastasis capacity in nude mice which were injected CSCs through the caudal vein. We are the first to reveal that BMI-1 could promote invasion and metastasis ability of pancreatic cancer stem cells. Finally, we identified that BMI-1 expression activating PI3K/AKT singing pathway by negative regulating PTEN was the main mechanism of promoting invasion and metastasis ability of pancreatic CSCs. In summary, our findings indicate that BMI-1 could be used as the therapeutic target to inhibiting CSCs-mediated pancreatic cancer metastasis.

Down-regulation of p57 (KIP2) cyclin-dependent kinase inhibitors accelerates the growth and invasion of hepatocellular carcinoma (HCC), suggesting that p57 may play an important role in liver carcinogenesis. However, the mechanism or oncogenic signal leading to p57 down-regulation in HCC remains to be determined. Herein, we demonstrated that Jab1/Csn5 expression is negatively correlated with p57 levels in HCC tissues. Kaplan-Meier analysis of tumor samples revealed that high Jab1/Csn5 expression with concurrent low p57 expression is associated with poor overall survival. The inverse pattern of Jab1 and p57 expression was also observed during carcinogenesis in a chemically induced rat HCC model. We also found that mechanistically, Jab1-mediated p57 proteolysis in HCC cells is dependent on 26S-proteasome inhibitors. We further demonstrated that direct physical interaction between Jab1 and p57 triggers p57 down-regulation, independently of Skp2 and Akt pathways, in HCC cells. These data suggest that Jab1 is an important upstream negative regulator of p57 and that aberrant expression of Jab1 in HCC could lead to a significant decrease in p57 levels and contribute to tumor cell growth. Furthermore, restoration of p57 levels induced by loss of Jab1 inhibited tumor cell growth and further increased cell apoptosis in HCC cells. Moreover, silencing Jab1 expression further enhanced the antitumor effects of cisplatin-induced apoptosis in HCC cells. Conclusion: Jab1-p57 pathway confers resistance to chemotherapy and may represent a potential target for investigational therapy in HCC. (HEPATOLOGY 2016;63:898-913) H epatocellular carcinoma (HCC) is the sixth most prevalent cancer in the world and is the third leading cause of cancer-related mortality. (1) Only 10% to 20% of HCC tumors can be removed completely by surgery in patients with HCC, and the reported cumulative 5-year recurrence rate after curative hepatectomy averages above 70% in both Eastern and Western medical centers. (2) At present, there is not only a lack of predictive and prognostic biomarkers in HCC patients but also a lack of effective therapeutic targets. Systemic treatment approaches are still the main option for patients with advanced HCC. Cisplatin-based regimens result in higher objective response rates than do non-cisplatin-based regimens in advanced HCC. However, the 15% response rate significantly limits the overall therapeutic benefit. (3) Abbreviations: CDK, cyclin-dependent kinase; HCC, hepatocellular carcinoma; siRNA, small interfering RNA; TCGA, the Cancer Genome Atlas; TGF-b, transforming growth factor b.

BackgroundThe increase in the levels of reactive oxygen species (ROS) in acute myeloid leukemia (AML) patients has been previously described; thus, it is important to regulate ROS levels in AML.MethodsFlow cytometry were used to assess the in vitro effect of compound kushen injection (CKI). Quantitative proteomics were used to analyse the mechanism. The AML patient-derived xenograft (PDX) model were used to evaluate the in vivo effect of CKI.ResultsWe found that intracellular ROS levels in AML cells were decreased, the antioxidant capacity were increased when treated with CKI. CKI inhibited the proliferation of AML cells and enhanced the cytotoxicity of AML cells, which has few toxic effects on haematopoietic stem cells (HSCs) and T cells. At the single-cell level, individual AML cells died gradually by CKI treatment on optofluidic chips. CKI promoted apoptosis and arrested cell cycle at G1/G0 phase in U937 cells. Furthermore, higher peroxiredoxin-3 (Prdx3) expression levels were identified in CKI-treated U937 cells through quantitative proteomics detection. Mechanically, the expression of Prdx3 and peroxiredoxin-2 (Prdx2) was up-regulated in CKI-treated AML cells, while thioredoxin 1 (Trx1) was reduced. Laser confocal microscopy showed that the proteins Prdx2 could be Interacted with Trx1 by CKI treatment. In vivo, the survival was longer and the disease was partially alleviated by decreased CD45+ immunophenotyping in peripheral blood in the CKI-treated group in the AML PDX model.ConclusionsAntioxidant CKI possess better clinical application against AML through the Prdxs/ROS/Trx1 signalling pathway.Electronic supplementary materialThe online version of this article (10.1186/s13046-018-0948-3) contains supplementary material, which is available to authorized users.

The identification of novel tumour-associated antigens is urgently needed to improve the efficacy of immunotherapy for multiple myeloma (MM). In this study, we identified a membrane protein MMSA-1 (multiple myeloma special antigen-1) that was specifically expressed in MM and exhibited significantly positive correlation with MM. We then identified HLA-A*0201-restricted MMSA-1 epitopes and tested their cytotoxic T lymphocyte (CTL) response. The MMSA-1 epitope SLSLLTIYV vaccine was shown to induce an obvious CTL response in vitro. To improve the immunotherapy, we constructed a multi-epitope peptide vaccine by combining epitopes derived from MMSA-1 and Dickkopf-1 (DKK1). The effector T cells induced by multi-epitope peptide vaccine-loaded dendritic cells lysed U266 cells more effectively than MMSA-1/DKK1 single-epitope vaccine. In myeloma-bearing severe combined immunodeficient mice, the multi-epitope vaccine improved the survival rate significantly compared with single-epitope vaccine. Consistently, multi-epitope vaccine decreased the tumour volume greatly and alleviated bone destruction. The frequencies of CD4 and CD8 T cells was significantly increased in mouse blood induced by the multi-epitope vaccine, indicating that it inhibits myeloma growth by changing T cell subsets and alleviating immune paralysis. This study identified a novel peptide from MMSA-1 and the multi-epitope vaccine will be used to establish appropriate individualized therapy for MM.

Purpose High levels of ROS and ineffective antioxidant systems contribute to oxidative stress, which affects the function of hematopoietic cells in acute myeloid leukemia (AML); however, the mechanisms by which ROS lead to malignant transformation in relapsed AML-M5 are not completely understood. We hypothesized that alterations in intracellular ROS would trigger AML-M5 relapse by activating the intrinsic pathway. Experimental Design We studied ROS levels and conducted JAB1/COPS5 and TRX gene expression analyses with blood samples obtained from 60 matched AML-M5 patients at diagnosis and relapse and conducted mechanism studies of Jab1’s regulation of Trx in leukemia cell lines. Results Our data showed that increased production of ROS and a low capacity of antioxidant enzymes were characteristics of AML-M5, both at diagnosis and at relapse. Consistently, increased gene expression levels of thioredoxin (TRX) and c-Jun activation domain-binding protein-1 (JAB1/COPS5) were associated with low overall survival rates in patients with AML-M5. In addition, stimulating AML-M5 cells with low concentrations of hydrogen peroxide led to increased Jab1 and Trx expression. Consistently, transfection of ectopic Jab1 into leukemia cells increased Trx expression, whereas silencing of Jab1 in leukemia cells reduced Trx expression. Mechanistically, Jab1 interacted with Trx and stabilized Trx protein. Moreover, Jab1 transcriptionally regulated Trx. Furthermore, depletion of Jab1 inhibited leukemia cell growth both in vitro and in vivo. Conclusions We identified a novel Jab1-Trx axis that is a key cellular process in the pathobiologic characteristics of AML-M5. Targeting the ROS/Jab1/Trx pathway could be beneficial in the treatment of AML-M5.