Yiran Huang

Metabonomic profiling of renal cell carcinoma: high-resolution proton nuclear magnetic resonance spectroscopy of human serum with multivariate data analysis.

Metabonomic profiling using proton nuclear magnetic resonance ((1)H NMR) spectroscopy and multivariate data analysis of human serum samples was used to characterize metabolic profiles in renal cell carcinoma (RCC). We found distinct, easily detectable differences between (a) RCC patients and healthy humans, (b) RCC patients with metastases and without metastases, and (c) RCC patients before and after nephrectomy. Compared to healthy human serum, RCC serum had higher levels of lipid (mainly very low-density lipoproteins), isoleucine, leucine, lactate, alanine, N-acetylglycoproteins, pyruvate, glycerol, and unsaturated lipid, together with lower levels of acetoacetate, glutamine, phosphatidylcholine/choline, trimethylamine-N-oxide, and glucose. This pattern was somewhat reversed after nephrectomy. Altered metabolite concentrations are most likely the result of the cells switching to glycolysis to maintain energy homeostasis following the loss of ATP caused by impaired TCA cycle in RCC. Serum NMR spectra combined with principal component analysis techniques offer an efficient, convenient way of depicting tumour biochemistry and stratifying tumours under different pathophysiological conditions. It may be able to assist early diagnosis and postoperative surveillance of human malignant diseases using single blood samples.

Hypoxia-inducible factor-1α-induced differentiation of myeloid leukemic cells is its transcriptional activity independent

Hypoxia or hypoxia mimetic has been shown to induce differentiation together with the accumulation of hypoxia-inducible factor-1α (HIF-1α) protein of myeloid leukemic cells and normal hematopoietic progenitors. To provide direct evidence for the role of HIF-1α in acute myeloid leukemia (AML) cell differentiation and its mechanisms, we generated myeloid leukemic U937T transformants, in which HIF-1α was tightly induced by tetracycline withdrawal. The results showed that the conditional HIF-1α induction triggered granulocytic differentiation of these transformants, while the suppression of HIF-1α expression by specific short hairpin RNAs (shRNAs) effectively inhibited hypoxia-induced differentiation of U937 cells, as evidenced by morphology, maturation-related antigens as well as expressions of myeloid differentiation signatures and hematopoietic cells-specific cytokine receptors. The specific shRNAs-inhibited expression of HIF-1β, an essential partner for transcription activity of HIF-1, failed, while the inhibition of hematopoietic differentiation-critical CCAAT/enhancer-binding protein-α (C/EBPα) significantly eliminated HIF-1α-mediated myeloid leukemic cell differentiation. Collectively, this work provided several lines of direct evidence for the role of HIF-1α protein through its nontranscriptional activity in myeloid cell differentiation, in which C/EBPα elicits a role as an effector downstream to HIF-1α. These discoveries would shed new insights for understanding mechanisms underlying leukemogenesis and designing the new therapeutic strategy for differentiation induction of AML.

Tumor-suppressive function of long noncoding RNA MALAT1 in glioma cells by downregulation of MMP2 and inactivation of ERK/MAPK signaling

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a type of long noncoding RNA. It is associated with metastasis and is a favorable prognostic factor for lung cancer. Recent studies have shown that MALAT1 plays an important role in other malignancies. But, little is known about the role of MALAT1 in glioma. In this study, quantitative reverse transcription PCR (qRT-PCR) was used to demonstrate that the expression of MALAT1 was lower than that in normal brain tissues. Stable RNA interference-mediated knockdown of MALAT1 in human glioma cell lines (U87 and U251) significantly promoted the invasion and proliferation of the glioma cells by in vitro assays. Conversely, overexpression of MALAT1 caused significant reduction in cell proliferation and invasion in vitro, and tumorigenicity in both subcutaneous and intracranial human glioma xenograft models. Furthermore, MALAT1-mediated tumor suppression in glioma cells may be via reduction of extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) signaling activity and expression of matrix metalloproteinase 2 (MMP2). In conclusion, overall data demonstrated the tumor-suppressive role of MALAT1 in glioma by attenuating ERK/MAPK-mediated growth and MMP2-mediated invasiveness.

Hypoxia‐induced downregulation of miR‐30c promotes epithelial‐mesenchymal transition in human renal cell carcinoma

MicroRNAs (miRNAs), which negatively regulate protein expression by binding protein‐coding mRNAs, have been integrated into cancer development and progression as either oncogenes or tumor suppressor genes. miR‐30c was reported to be downregulated in several types of cancer. However, its role in human renal cell carcinoma (RCC) remains largely unknown. Here, we show that miR‐30c is significantly downregulated in human RCC tissues and cell lines. We found that miR‐30c downregulation could be induced by hypoxia in RCC cells in a hypoxia‐inducible factors (HIFs) dependent manner. Repression of miR‐30c through its inhibitor resulted in reduction of E‐cadherin production and promotion of epithelial‐mesenchymal transition (EMT), while overexpression of miR‐30c inhibited EMT in RCC cells. We identified Slug as a direct target of miR‐30c in RCC cells. Slug was upregulated in RCC tissues and its expression could be induced by hypoxia, which is consistent with downregulation of miR‐30c by hypoxia. Forced overexpression of Slug in 786‐O cells reduced E‐cadherin production, and promoted EMT as well as cell migration. Moreover, Slug overexpression abrogated the inhibitory role of miR‐30c in regulating EMT and cell migration, indicating miR‐30c regulates EMT through Slug in RCC cells. Our findings propose a model that hypoxia induces EMT in RCC cells through downregulation of miR‐30c, which leads to subsequent increase of Slug expression and repression of E‐cadherin production, and suggest a potential application of miR‐30c in RCC treatment.

Derivation of male germ cells from induced pluripotent stem cells in vitro and in reconstituted seminiferous tubules.

Previous studies have demonstrated that mouse‐ and human‐induced pluripotent stem (iPS) cells can differentiate into primordial germ cells in vitro. However, up to now it is not known whether iPS cells would be able to differentiate into male germ cells in vivo. The aim of this study was to explore differentiation potential of iPS cells to male germ cells in vitro and in vivo.

The interaction between mesenchymal stem cells and steroids during inflammation

Mesenchymal stem cells (MSCs) are believed to exert their regenerative effects through differentiation and modulation of inflammatory responses. However, the relationship between the severity of inflammation and stem cell-mediated tissue repair has not been formally investigated. In this study, we applied different concentrations of dexamethasone (Dex) to anti-CD3-activated splenocyte cultured with or without MSCs. As expected, Dex exhibited a classical dose-dependent inhibition of T-cell proliferation. Surprisingly, although MSCs also blocked T-cell proliferation, the presence of Dex unexpectedly showed a dose-dependent reversion of T-cell proliferation. This effect of Dex was found to be exerted through interfering STAT1 phosphorylation-prompted expression of inducible nitric oxide synthase (iNOS). Interestingly, inflammation-induced chemokines in MSCs was unaffected. To test the role of inflammation severity in stem cell-mediated tissue repair, we employed mice with carbon tetrachloride-induced advanced liver fibrosis and found that although MSCs alone were effective, concurrent administration of Dex abrogated the therapeutic effects of MSCs on fibrin deposition, serum levels of bilirubin, albumin, and aminotransferases, as well as T-lymphocyte infiltration, especially IFN-γ+CD4+ and IL-17A+CD4+T cells. Likewise, iNOS−/− MSCs, which produce chemokines but not nitric oxide under inflammatory conditions, are ineffective in treating advanced liver fibrosis. Therefore, inflammation has a critical role in MSC-mediated tissue repair. In addition, concomitant application of MSCs with steroids should be avoided.

Complement C5a exacerbates acute lung injury induced through autophagy-mediated alveolar macrophage apoptosis

Intestinal ischemia has a high mortality and often causes acute lung injury (ALI), which is a serious complication, and is accompanied by high mortality up to 40%. An intense local and systemic inflammation occurs during intestinal ischemia/reperfusion (IR)-induced lung injury resulting from activation of immune responses. It has been reported that one component of complement, C5a, is indispensable for the full development of IR-induced lung injury, whereas the detailed molecular mechanism remains to be elucidated. In this study, we found that intestinal IR induced ALI-like symptoms, and C5a receptor (C5aR) expression was upregulated in alveolar macrophages, which are resident macrophages in lung tissue and are important in pulmonary homeostasis. C5a produced during lung injury binds to C5aR in alveolar macrophages, initiates downstream signaling that promotes autophagy, leading to apoptosis of alveolar macrophages. Using Mφ-ATG5−/− mice, in which the atg5 is deficient specifically in macrophages and autophagy is inhibited, we confirmed that in vivo C5a interacting with C5aR induced autophagy in alveolar macrophages, which promoted alveolar macrophage apoptosis. Further study indicated that autophagy was induced through C5aR-mediated degradation of bcl-2. Taken together, our results demonstrated that C5aR-mediated autophagy induced apoptosis in alveolar macrophages, disrupting pulmonary homeostasis and contributing to the development of ALI. This novel mechanism suggests new therapeutic potential of autophagy regulation in ALI.

p53 regulates mesenchymal stem cell-mediated tumor suppression in a tumor microenvironment through immune modulation.

p53 is one of the most studied genes in cancer biology, and mutations in this gene may be predictive for the development of many types of cancer in humans and in animals. However, whether p53 mutations in non-tumor stromal cells can affect tumor development has received very little attention. In this study, we show that B16F0 melanoma cells form much larger tumors in p53-deficient mice than in wild-type mice, indicating a potential role of p53 deficiency in non-tumor cells of the microenvironment. As mesenchymal stem cells (MSCs) are attracted to tumors and form a major component of the tumor microenvironment, we examined the potential role of p53 status in MSCs in tumor development. We found that larger tumors resulted when B16F0 melanoma cells were co-injected with bone marrow MSCs derived from p53-deficient mice rather than MSCs from wild-type mice. Interestingly, this tumor-promoting effect by p53-deficient MSCs was not observed in non-obese diabetic/severe combined immunodeficiency mice, indicating the immune response has a critical role. Indeed, in the presence of inflammatory cytokines, p53-deficient MSCs expressed more inducible nitric oxide synthase (iNOS) and exhibited greater immunosuppressive capacity. Importantly, tumor promotion by p53-deficient MSCs was abolished by administration of S-methylisothiourea, an iNOS inhibitor. Therefore, our data demonstrate that p53 status in tumor stromal cells has a key role in tumor development by modulating immune responses.

Effect of remote ischaemic preconditioning on renal protection in patients undergoing laparoscopic partial nephrectomy: a ‘blinded’ randomised controlled trial

To evaluate whether remote ischaemic preconditioning (RIPC) reduces renal injury in patients undergoing laparoscopic partial nephrectomy (LPN).

ALDH1 is an independent prognostic factor for patients with stages II-III rectal cancer after receiving radiochemotherapy.

Background:About one in five patients with locally advanced rectal cancer (RC) suffers recurrence or distant metastasis after neoadjuvant therapy. We investigated how cancer stem cell markers change after neoadjuvant therapy and how these markers relate to recurrence.Methods:Pretreatment biopsies and postoperative specimens were taken from 64 patients with locally advanced rectal adenocarcinoma who received preoperative radiochemotherapy (RCT) between sampling. Samples were tested immunohistochemically for CD44, LGR5, ALDH1 and CD166; scores were dichotomised as high or low. The median follow-up period was 36 months.Results:High expression of CD44, LGR5, ALDH and CD166 was found in 38%, 5%, 48% and 10%, respectively, before RCT and 86%, 33%, 71% and 52%, respectively, after RCT. CD44 (P=0.001), LGR5 (P=0.049) and CD166 (P=0.003) were significantly upregulated after RCT. Whereas no recurrence was seen during the follow-up in the low ALDH group, 40% of the high ALDH group suffered recurrence. In multivariate COX analysis, postoperative ALDH1 independently predicted poor prognosis in patients with RC who received RCT (P=0.0095).Conclusion:Preoperative RCT upregulates expression of stem cell markers in patients with RC. High post-treatment ALDH1 expression predicts poor prognosis for these patients after neoadjuvant therapy.