[miR-216b suppresses cell proliferation and invasion by targeting PKCα in nasopharyngeal carcinoma cells].

OBJECTIVE: To elucidate whether miR-216b suppresses cell proliferation and invasion by targeting PKCα, thus to reveal the molecular mechanism that miR-216b functions as a tumor suppressor in nasopharyngeal carcinoma (NPC). METHODS: PKCα 3'UTR-luciferase vector was constructed and dual-luciferase reporter gene assay was employed to examine the effect of miR-216b on luciferase activity. Nasopharyngeal cancer CNE2 cells were transfected with miR-216b mimics, and then qRT-PCR and Western blotting were performed to detect the expressions of PKCa mRNA and protein. The effects of PKCα downregulation on cell proliferation and invasion were assessed after PKCα siRNA were transfected into CNE2 cells. CNE2 cells were cotransfected with miR-216b mimics and PKCα plasmid, and the proliferation of CNE2 cells was assayed using a MTS cell proliferation assay kit. RESULTS: The results of dual-luciferase reporter gene assay demonstrated that miR-216b could bind to the 3'-untranslated region (UTR) of PKCα and inhibited the luciferase activity to 62.4% of that of the mimics control cells. The expressions of PKCα mRNA and protein were significantly down-regulated by 49.1% and 55.7%, respectively, in comparison with that of the control cells. siRNA-mediated downregulation of PKCα suppressed the proliferation and invasion ability of CNE2 cells, and could partially mimic the tumor-inhibiting effect of miR-216b. Moreover, the overexpressed PKCα may partially reverse the inhibitory effect of miR-216b on proliferation of CNE2 cells. CONCLUSION: miR-216b suppresses cell proliferation and invasion by targeting PKCα in NPC cells.

Multifunctional microfluidic chip for cancer diagnosis and treatment.

Microfluidic chip is not a chip in the traditional sense. It is technologies that control fluids at the micro level. As a burgeoning biochip, microfluidic chips integrate multiple disciplines, including physiology, pathology, cell biology, biophysics, engineering mechanics, mechanical design, materials science, and so on. The application of microfluidic chip has shown tremendous promise in the field of cancer therapy in the past three decades. Various types of cell and tissue cultures, including 2D cell culture, 3D cell culture and tissue organoid culture could be performed on microfluidic chips. Patient-derived cancer cells and tissues can be cultured on microfluidic chips in a visible, controllable, and high-throughput manner, which greatly advances the process of personalized medicine. Moreover, the functionality of microfluidic chip is greatly expanding due to the customizable nature. In this review, we introduce its application in developing cancer preclinical models, detecting cancer biomarkers, screening anti-cancer drugs, exploring tumor heterogeneity and producing nano-drugs. We highlight the functions and recent development of microfluidic chip to provide references for advancing cancer diagnosis and treatment.

Aromatase (P450arom) and 11beta-hydroxylase (P45011beta) genes are differentially expressed during the sex change process of the protogynous rice field eel, Monopterus albus.

Steroids are known to play a crucial role in gonadal sex differentiation in many non-mammalian vertebrates, but also in the gonadal sex change of hermaphroditic teleosts. We investigated the expression of two genes encoding key steroidogenic enzymes, i.e., cytochrome P450 aromatase (P450arom) and cytochrome P45011beta-hydroxylase (P45011beta), during the sex change of the protogynous rice field eel, Monopterus albus. Using RT-PCR with degenerate primers, we cloned rice field eel homologous fragments for both genes (rcP450arom and rcP45011beta) as indicated by the high level of homology with P450arom and P45011beta sequences from various vertebrates. Gonadal expression of rcP450arom and rcP45011beta mRNA levels were then assessed during the sex change by semi-quantitative RT-PCR and a real-time RT-PCR. rcP450arom was predominantly expressed in ovary, much less in ovotestis, and barely in testis. Conversely, P45011beta was markedly up-regulated at the onset of testicular development. These findings underline that regulation of steroidogenesis is an important process in the sex change of protogynous rice field eel, and they clearly indicate that the concomitant down-regulation of P450arom and up-regulation of P45011beta are of pivotal importance to the sex change of this species.

CHD1L contributes to cisplatin resistance by upregulating the ABCB1-NF-κB axis in human non-small-cell lung cancer.

Chromodomain helicase/ATPase DNA binding protein 1-like gene (CHD1L) is a recently identified gene associated with malignant tumor progression and patient chemotherapy resistance in human hepatocellular carcinoma (HCC). Previously, we found an association between CHD1L overexpression and poor patient survival in non-small-cell lung cancer (NSCLC). However, little is known about the relationship between CHD1L expression and chemotherapy resistance of NSCLC. By employing immunohistochemistry, we analyzed the expression of CHD1L in NSCLC samples and elucidated the roles and mechanism of CHD1L in NSCLC chemoresistance. We found that the increased expression of CHD1L is positively correlated with a shorter survival time of patients who had received chemotherapy after surgery. We also found that the expression of CHD1L was increased after cisplatin treatment in A549 cells. Conversely, the depletion of CHD1L in cisplatin-resistance cells increased the cell sensitivity to cisplatin, indicating that CHD1L plays a critical role in cisplatin resistance of NSCLC cells. Importantly, we identified the ATP-Binding Cassette Sub-Family B Member (ABCB1) gene as a potential downstream target of CHD1L in NSCLC cells. Knocking down ABCB1 coupled with ectopic expression of CHD1L enhanced the effect of cisplatin on NSCLC cells apoptosis. In addition, overexpressed CHD1L increase the transcription of c-Jun which targeted directly to the promoter of ABCB1. Our data demonstrate that CHD1L could induce cisplatin resistance in NSCLC via c-Jun-ABCB1-NF-κB axis, and may serve as a novel predictive marker and the potential therapeutic target for cisplatin resistance in NSCLC.

[Effects of aging time on the form transformation and eco-toxicity threshold (ECx) of added Zn in typical China soils].

Six typical China soils with different properties were selected and added with seven concentrations of ZnCl2 to study the effects of different aging time (14, 90, 180, 360, and 540 days) on the form transformation and eco-toxicity threshold (ECx) of added Zn in the soils, with the main affecting factors analyzed. The results indicated that with the increase of aging time, the fraction of 0.01 mol x L(-1) CaCl2-extracted Zn in the soils decreased sharply initially, then slowed down, and reached the dynamic balance after 540 d incubation. The eco-toxicity thresholds (ECx, x = 10, 50) of Zn to bok choy increased significantly with aging time (P < 0.05), which implied the marked decrease of the phyto-toxicity of Zn. The measured aging factors AF10 and AF50 of Zn ranged from 1.077-1.743 and 1.174-1.441, respectively, and increased with aging time. The balanced concentration of Zn in the soils was significantly negatively correlated with soil pH, CEC, and organic carbon (Org-C) content, and soil pH was the most important controlling factor, followed by CEC and Org-C. It took shorter time to reach Zn balance in the soils with higher pH. The prediction model of the ECx of Zn was developed based on the aging factors and the main soil properties, and could be well validated by the measured ECx under field condition. This study would provide theoretical basis for the normalization of the eco-toxicity thresholds of added Zn in different soils and the formulation of the environmental criterion of Zn in China soils.

miR-26a suppresses tumor growth and metastasis by targeting FGF9 in gastric cancer.

The role of miR-26a in cancer cells seemed controversial in previous studies. Until now, the role of miR-26a in gastric cancer remains undefined. In this study, we found that miR-26a was strongly downregulated in gastric cancer (GC) tissues and cell lines, and its expression levels were associated with lymph node metastasis and clinical stage, as well as overall survival and replase-free survival of GC. We also found that ectopic expression of miR-26a inhibited GC cell proliferation and GC metastasis in vitro and in vivo. We further identified a novel mechanism of miR-26a to suppress GC growth and metastasis. FGF9 was proved to be a direct target of miR-26a, using luciferase assay and western blot. FGF9 overexpression in miR-26a-expressing cells could rescue invasion and growth defects of miR-26a. In addition, miR-26a expression inversely correlated with FGF9 protein levels in GC. Taken together, our data suggest that miR-26a functions as a tumor suppressor in GC development and progression, and holds promise as a prognostic biomarker and potential therapeutic target for GC.

RNAi knockdown of PIK3CA preferentially inhibits invasion of mutant PIK3CA cells.

AIM: To explore the effects of siRNA silencing of PIK3CA on proliferation, migration and invasion of gastric cancer cells and to investigate the underlying mechanisms. METHODS: The mutation of PIK3CA in exons 9 and 20 of gastric cancer cell lines HGC-27, SGC-7901, BGC-823, MGC-803 and MKN-45 was screened by polymerase chain reaction (PCR) followed by sequencing. BGC-823 cells harboring no mutations in either of the exons, and HGC-27 cells containing PIK3CA mutations were employed in the current study. siRNA targeting PIK3CA was chemically synthesized and was transfected into these two cell lines in vitro. mRNA and protein expression of PIK3CA were detected by real-time PCR and Western blotting, respectively. We also measured phosphorylation of a serine/threonine protein kinase (Akt) using Western blotting. The proliferation, migration and invasion of these cells were examined separately by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), wound healing and Transwell chambers assay. RESULTS: The siRNA directed against PIK3CA effectively led to inhibition of both endogenous mRNA and protein expression of PIK3CA, and thus significantly down-regulated phosphorylation of Akt (P < 0.05). Furthermore, simultaneous silencing of PIK3CA resulted in an obvious reduction in tumor cell proliferation activity, migration and invasion potential (P < 0.01). Intriguing, mutant HGC-27 cells exhibited stronger invasion ability than that shown by wild-type BGC-823 cells. Knockdown of PIK3CA in mutant HGC-27 cells contributed to a reduction in cell invasion to a greater extent than in non-mutant BGC-823 cells. CONCLUSION: siRNA mediated targeting of PIK3CA may specifically knockdown the expression of PIK3CA in gastric cancer cells, providing a potential implication for therapy of gastric cancer.

[Studies on IFN-gamma-mediated reversion of CIK killing sensitivity to edited human lung cancer A549 cells].

AIM: To explore IFN-gamma-mediated reversion of CIK killing sensitivity to immunoedited lung cancer A549 cells. METHODS: RT-PCR and MTT methods were used to detect the effect on MICA mRNA expression induced by IFN-gamma in the edited A549 cells and the change of CIK killing sensitivity to A549 cells, respectively. RESULTS: Low expression of cell surface MICA and low killing sensitivity of CIKs were observed in edited A549 cells. IFN-gamma could significantly increase MICA mRNA expression in the edited A549 cells and improve CIK cell cytotoxicity. CONCLUSION: IFN-gamma could reverse CIK killing sensitivity to the edited A549 cells by enhancing the MICA mRNA expression.

Up-regulation of PIK3CA promotes metastasis in gastric carcinoma.

AIM: To explore expressions of PIK3CA in the progression of gastric cancer from primary to metastasis and its effects on activation of phosphatidylinositol 3-kinase (PI3K)/Akt pathway. METHODS: mRNA and protein levels of PIK3CA were assessed, respectively, by real-time quantitative polymerase chain reaction and immunohistochemistry in specimens of normal gastric mucosa, primary foci and lymph node and distant metastasis of gastric cancer. Akt and phosphorylated Akt protein were also examined by Western blotting in these tissues, in order to analyze the effect of PIK3CA expression level changes on the activation of PI3K/Akt signaling pathway. RESULTS: PIK3CA mRNA in lymph node metastasis were approximately 5 and 2 folds higher, respectively, than that in the corresponding normal gastric mucosa and primary gastric cancer tissues (P < 0.05), while no statistical significance was found compared with distant metastasis. Immunohistochemically, PIK3CA protein expression was discovered in 7 (35%) specimens of 20 primary foci vs 10 (67%) of 15 of lymph node metastasis or 11 (61%) of 18 of distant metastasis (35% vs 67%, P = 0.015; 35% vs 61%, P = 0.044). With the increased level of PIK3CA expression, the total Akt protein expression remained almost unchanged, but p-Akt protein was upregulated markedly. CONCLUSION: Increased expression of PIK3CA is expected to be a promising indicator of metastasis in gastric cancer. Up-regulation of PIK3CA may promote the metastasis of gastric cancer through aberrant activation of PI3K/Akt signaling.