ABSTRACT
BACKGROUND: BRAFV600E is the most common genetic mutation in differentiated thyroid cancer (DTC) occurring in 60% of patients and drives malignant tumour cell phenotypes including proliferation, metastasis and immune-escape. BRAFV600E-mutated papillary thyroid cancer (PTC) also displays greatly reduced expression of thyroid differentiation markers, thus tendency to radioactive iodine (RAI) refractory and poor prognosis. Therefore, understanding the molecular mechanisms and main oncogenic events underlying BRAFV600E will guide future therapy development. METHODS: Bioinformatics and clinical specimen analyses, genetic manipulation of BRAFV600E-induced PTC model, functional and mechanism exploration guided with transcriptomic screening, as well as systematic rescue experiments were applied to investigate miR-31 function within BRAFV600E-induced thyroid cancer development. Besides, nanoparticles carrying miR-31 antagomirs were testified to alleviate 131I iodide therapy on PTC models. RESULTS: We identify miR-31 as a significantly increased onco-miR in BRAFV600E-associated PTC that promotes tumour progression, metastasis and RAI refractoriness via sustained Wnt/ß-catenin signalling. Mechanistically, highly activated BRAF/MAPK pathway induces miR-31 expression via c-Jun-mediated transcriptional regulation across in vitro and transgenic mouse models. MiR-31 in turn facilitates ß-catenin stabilisation via directly repressing tumour suppressors CEBPA and DACH1, which direct the expression of multiple essential Wnt/ß-catenin pathway inhibitors. Genetic functional assays showed that thyroid-specific knockout of miR-31 inhibited BRAFV600E-induced PTC progression, and strikingly, enhanced expression of sodium-iodide symporter and other thyroid differentiation markers, thus promoted 131I uptake. Nanoparticle-mediated application of anti-miR-31 antagomirs markedly elevated radio-sensitivity of BRAFV600E-induced PTC tumours to 131I therapy, and efficiently suppressed tumour progression in the pre-clinical mouse model. CONCLUSIONS: Our findings elucidate a novel BRAF/MAPK-miR-31-Wnt/ß-catenin regulatory mechanism underlying clinically BRAFV600E-associated DTC tumourigenesis and dedifferentiation, also highlight a potential adjuvant therapeutic strategy for advanced DTC.
Subject(s)
MicroRNAs , Proto-Oncogene Proteins B-raf , Thyroid Neoplasms , Animals , Humans , Mice , Carcinogenesis/genetics , Cell Dedifferentiation/genetics , Cell Dedifferentiation/drug effects , MicroRNAs/genetics , MicroRNAs/metabolism , Proto-Oncogene Proteins B-raf/genetics , Proto-Oncogene Proteins B-raf/metabolism , Thyroid Cancer, Papillary/genetics , Thyroid Cancer, Papillary/metabolism , Thyroid Cancer, Papillary/pathology , Thyroid Neoplasms/genetics , Thyroid Neoplasms/pathology , Thyroid Neoplasms/metabolismABSTRACT
BACKGROUND: PTPRF interacting protein alpha 1 (PPFIA1) is reportedly related to the occurrence and progression of several kinds of malignancies. However, its role in esophageal squamous cell carcinoma (ESCC) is unclear. This current study investigated the prognostic significance and biological functions of PPFIA1 in ESCC. METHODS: Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA), and Gene Expression Omnibus (GEO) were used to investigate PPFIA1 expression in esophageal cancer. The relationship between PPFIA1 expression and clinicopathological characteristics and patient survival was evaluated in GSE53625 dataset, and verified in the cDNA array based on qRT-PCR and tissue microarray (TMA) dataset based on immunohistochemistry. The impact of PPFIA1 on the migration and invasion of cancer cells were investigated by wound-healing and transwell assays, respectively. RESULTS: The expression of PPFIA1 was obviously increased in ESCC tissues versus adjacent esophageal tissues according to online database analyses (all P < 0.05). High PPFIA1 expression was closely related to several clinicopathological characteristics, including tumor location, histological grade, tumor invasion depth, lymph node metastasis, and tumor-node-metastasis (TNM) stage. High PPFIA1 expression was related to worse outcomes and was identified as an independent prognostic factor of overall survival in ESCC patients (GSE53625 dataset, P = 0.019; cDNA array dataset, P < 0.001; TMA dataset, P = 0.039). Downregulation of PPFIA1 expression can significantly reduce the migration and invasion ability of ESCC cells. CONCLUSION: PPFIA1 is related to the migration and invasion of ESCC cells, and can be used as a potential biomarker to evaluate the prognosis of ESCC patients.
Subject(s)
Esophageal Neoplasms , Esophageal Squamous Cell Carcinoma , Humans , Esophageal Squamous Cell Carcinoma/genetics , Esophageal Neoplasms/genetics , Data Interpretation, Statistical , Down-Regulation , Gene Expression Profiling , Adaptor Proteins, Signal TransducingABSTRACT
Emerging evidence suggests that the cancer stem cells (CSCs) are key culprits of cancer metastasis and drug resistance. Understanding mechanisms regulating the critical oncogenic pathways and CSCs function could reveal new diagnostic and therapeutic strategies. We now report that miR-22, a miRNA critical for hair follicle stem/progenitor cell differentiation, promotes tumor initiation, progression, and metastasis by maintaining Wnt/ß-catenin signaling and CSCs function. Mechanistically, we find that miR-22 facilitates ß-catenin stabilization through directly repressing citrullinase PAD2. Moreover, miR-22 also relieves DKK1-mediated repression of Wnt/ß-catenin signaling by targeting a FosB-DDK1 transcriptional axis. miR-22 knockout mice showed attenuated Wnt/ß-catenin activity and Lgr5+ CSCs penetrance, resulting in reduced occurrence, progression, and metastasis of chemically induced cutaneous squamous cell carcinoma (cSCC). Clinically, miR-22 is abundantly expressed in human cSCC. Its expression is even further elevated in the CSCs proportion, which negatively correlates with PAD2 and FosB expression. Inhibition of miR-22 markedly suppressed cSCC progression and increased chemotherapy sensitivity in vitro and in xenograft mice. Together, our results revealed a novel miR-22-WNT-CSCs regulatory mechanism in cSCC and highlight the important clinical application prospects of miR-22, a common target molecule for Wnt/ß-catenin signaling and CSCs, for patient stratification and therapeutic intervention.
Subject(s)
Carcinoma, Squamous Cell , Animals , Humans , Mice , Skin Neoplasms , beta CateninABSTRACT
OBJECTIVE: To explore the relationship between body mass index (BMI) and clinicopathological characteristics in patients with papillary thyroid carcinoma (PTC). METHODS: The clinical data of 1,579 patients with PTC, admitted to our hospital from May 2016 to March 2017, were retrospectively analyzed. According to the different BMI of patients, it can be divided into underweight recombination (BMI < 18.5 kg/m), normal body recombination (18.5 ≤ BMI < 24.0 kg/m2), overweight recombination (24.0 ≤ BMI < 28.0 kg/m2) and obesity group (BMI ≥ 28.0 kg/m2). The clinicopathological characteristics of PTC in patients with different BMIs group were compared. RESULTS: In our study, the risk for extrathyroidal extension (ETE), advanced T stage (T III/IV), and advanced tumor-node-metastasis stage (TNM III/IV) in the overweight group were higher, with OR (odds ratio) = 1.99(1.41-2.81), OR = 2.01(1.43-2.84), OR = 2.94(1.42-6.07), respectively, relative to the normal weight group. The risk for ETE and T III/IV stage in the obese group were higher, with OR = 1.82(1.23-2.71) and OR = 1.82(1.23-2.70), respectively, relative to the normal weight group. CONCLUSION: BMI is associated with the invasiveness of PTC. There is a higher risk for ETE and TNM III/IV stage among patients with PTC in the overweight group and for ETE among patients with PTC in the obese group.
ABSTRACT
Background: Patients with metastatic radioiodine-refractory papillary thyroid carcinoma (PTC) have limited treatment options and a poor prognosis. There is an urgent need to develop new drugs targeting PTC for clinical application. Apatinib, a novel small-molecule tyrosine kinase inhibitor (TKI), is highly selective for vascular endothelial growth factor receptor-2 (VEGFR2) and exhibits antitumor effects in a variety of solid tumors. Although apatinib has been shown to be safe and efficacious in radioiodine-refractory differentiated thyroid cancer, the mechanism underlying its antitumor effect is unclear. In this report, we explored the effects of apatinib on PTC in vitro and in vivo. Methods: VEGFR2 expression levels were evaluated by immunohistochemistry (IHC), qPCR, and western blotting (WB). The effects of apatinib on cell viability, colony formation, and migration in the Transwell assay were assessed in vitro, and its effect on tumor growth rate was assessed in vivo. In addition, the levels of proteins in signaling pathways were determined by WB. Finally, the autophagy level was assessed by WB, immunofluorescence (IF), and transmission electron microscopy. Results: We found that high VEGFR2 expression is associated with tumor size, T stage, and lymph node metastasis in patients with PTC and that apatinib inhibits PTC cell growth, promotes apoptosis, and induces cell cycle arrest through the PI3K/Akt/mTOR signaling pathway. Moreover, apatinib induces autophagy, and pharmacological inhibition of autophagy or small interfering RNA (siRNA)-mediated targeting of autophagy-associated gene 5 (ATG5) can further increase PTC cell apoptosis. Conclusion: Our data suggest that apatinib can induce apoptosis and autophagy via the PI3K/Akt/mTOR signaling pathway for the treatment of PTC and that autophagy is a potential novel target for future therapy in resistant PTC.
ABSTRACT
The heat shock protein 70 (Hsp70) is upregulated in response to stress and has been implicated as a stress marker in temporal lobe epilepsy (TLE). However, whether Hsp70 plays a pathologic or protective role in TLE remains unclear. Here we report a deleterious role of Hsp70 in kainic acid (KA)-induced seizures. Hsp70 expression is upregulated in a KA model of TLE, and silencing or inhibition of Hsp70 suppresses neuronal hyperexcitability and attenuates acute or chronic epilepsy by enhancing A-type potassium current in hippocampal neurons. Hsp70 upregulation leads to proteosomal degradation of Kv4-KChIP4a channel complexes primarily encoding neuronal A-type current. Furthermore, Hsp70 directly binds to the N terminus of auxiliary KChIP4a and targets Kv4-KChIP4a complexes to proteasome. Taken together, our findings reveal a role of Hsp70 in the pathogenesis of epilepsy through degradation of Kv4-KChIP4a complexes, and pharmacological inhibition of Hsp70 may represent therapeutic potential for epilepsy or hyperexcitability-related neurological disorders.
Subject(s)
Epilepsy/genetics , HSP70 Heat-Shock Proteins/metabolism , Potassium/metabolism , Animals , MaleABSTRACT
Overexpression of the Ca2+-activated chloride channel ANO1/TMEM16A is implicated in tumorigenesis, and inhibition of ANO1 overexpression suppresses xenograft tumor growth and invasiveness. However, the underlying molecular mechanism for ANO1 inhibition in suppression of tumorigenesis remains unknown. Here, we show that silencing or inhibition of endogenous ANO1 inhibits cell growth, induces apoptosis and upregulates TNF-α expression in prostate cancer PC-3 cells. Enhancement of TNF-α signaling by ANO1 knockdown leads to upregulation of phosphorylated Fas-associated protein with death domain and caspase activation. Furthermore, silencing of ANO1 inhibits growth of PC-3 xenograft tumors in nude mice and induces apoptosis in tumors via upregulation of TNF-α signaling. Taken together, our findings provide mechanistic insight into promoting apoptosis in prostate cancer cells by ANO1 inhibition through upregulation of TNF-α signaling.
Subject(s)
Anoctamin-1/antagonists & inhibitors , Apoptosis , Neoplasm Proteins/antagonists & inhibitors , Prostatic Neoplasms/metabolism , Prostatic Neoplasms/pathology , Signal Transduction , Tumor Necrosis Factor-alpha/metabolism , Animals , Anoctamin-1/metabolism , Caspases/metabolism , Cell Line, Tumor , Cell Proliferation , Fas-Associated Death Domain Protein/metabolism , Gene Silencing , Humans , Male , Mice, Inbred BALB C , Mice, Nude , Models, Biological , Neoplasm Proteins/metabolism , Phosphorylation , Xenograft Model Antitumor AssaysABSTRACT
Unconventional myosin VIIA (Myo7a) is an actin-based motor molecule that normally functions in the cochlear hair cells of the inner ear. Mutations of MYO7A/Myo7a have been implicated in inherited deafness in both humans and mice. However, there is limited information about the functions of Myo7a outside of the specialized cells of the ears. Herein, we report a previously unidentified function of Myo7a by demonstrating that it plays an important role in melanoma progression. We found that silencing Myo7a by means of RNAi inhibited melanoma cell growth through upregulation of cell cycle regulator p21 (also known as CDKN1A) and suppressed melanoma cell migration and invasion through downregulation of RhoGDI2 (also known as ARHGDIB) and MMP9. Furthermore, Myo7a depletion suppressed melanoma cell metastases to the lung, kidney and bone in mice. In contrast, overexpression of Myo7a promoted melanoma xenograft growth and lung metastasis. Importantly, Myo7a levels are remarkably elevated in human melanoma patients. Collectively, we demonstrated for the first time that Myo7a is able to function in non-specialized cells, a finding that reveals the complicated disease-related roles of Myo7a, especially in melanomas.
Subject(s)
Cyclin-Dependent Kinase Inhibitor p21/genetics , Melanoma/genetics , Myosins/genetics , rho Guanine Nucleotide Dissociation Inhibitor beta/genetics , Animals , Bone Neoplasms/genetics , Bone Neoplasms/pathology , Bone Neoplasms/secondary , Cell Movement/genetics , Cell Proliferation/genetics , Disease Progression , Ear, Inner/metabolism , Ear, Inner/pathology , Gene Expression Regulation, Neoplastic , Gene Silencing , Hair Cells, Auditory/metabolism , Hair Cells, Auditory/pathology , Humans , Kidney Neoplasms/genetics , Kidney Neoplasms/pathology , Kidney Neoplasms/secondary , Lung Neoplasms/genetics , Lung Neoplasms/pathology , Lung Neoplasms/secondary , Matrix Metalloproteinase 9/genetics , Melanoma/pathology , Mice , Mutation , Myosin VIIa , Myosins/antagonists & inhibitors , Neoplasm Invasiveness/genetics , Neoplasm Invasiveness/pathology , Xenograft Model Antitumor AssaysABSTRACT
ANO1, a calcium-activated chloride channel, has been reported to be amplified or overexpressed in tissues of several cancers. However, reports on its roles in tumor progression obtained from cancer cell lines are inconsistent, suggesting that the role of ANO1 in tumorigenesis is likely dependent on either its expression level or cell-type expressing ANO1. To investigate the biological roles of ANO1 in different tumor cells, we, in this study, selected several cancer cell lines and a normal HaCaT cell line with high expression levels of ANO1, and examined the function of ANO1 in these cells using approaches of lentiviral knockdown and pharmacological inhibition. We found that ANO1 knockdown significantly inhibited cell proliferation and induced cell apoptosis in either tumor cell lines or normal HaCaT cell line. Moreover, silencing ANO1 arrested cancer cells at G1 phase of cell cycle. Treatment with ANO1 inhibitor CaCCinh-A01 reduced cell viability in a dose-dependent manner. Furthermore, both ANO1 inhibitors CaCCinh-A01 and T16Ainh-A01 significantly suppressed cell migration. Our findings show that ANO1 overexpression promotes cancer cell proliferation and migration; and genetic or pharmacological inhibition of ANO1 induces apoptosis and cell cycle arrest at G1 phase in different types of epithelium-originated cancer cells.
Subject(s)
Anoctamin-1/antagonists & inhibitors , Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Neoplasm Proteins/antagonists & inhibitors , Neoplasms, Glandular and Epithelial/drug therapy , Pyrimidines/pharmacology , Thiazoles/pharmacology , Thiophenes/pharmacology , Anoctamin-1/genetics , Anoctamin-1/metabolism , Cell Movement/drug effects , Cell Proliferation/drug effects , Dose-Response Relationship, Drug , G1 Phase Cell Cycle Checkpoints/drug effects , Gene Expression Regulation, Neoplastic , HCT116 Cells , HEK293 Cells , HT29 Cells , Humans , Neoplasm Proteins/genetics , Neoplasm Proteins/metabolism , Neoplasms, Glandular and Epithelial/genetics , Neoplasms, Glandular and Epithelial/metabolism , Neoplasms, Glandular and Epithelial/pathology , RNA Interference , Signal Transduction/drug effects , Time Factors , TransfectionABSTRACT
Lung cancer or pulmonary carcinoma is primarily derived from epithelial cells that are thin and line on the alveolar surfaces of the lung for gas exchange. ANO1/TMEM16A, initially identified from airway epithelial cells, is a member of Ca2+-activated Cl- channels (CaCCs) that function to regulate epithelial secretion and cell volume for maintenance of ion and tissue homeostasis. ANO1/TMEM16A has recently been shown to be highly expressed in several epithelium originated carcinomas. However, the role of ANO1 in lung cancer remains unknown. In this study, we show that inhibition of calcium-activated chloride channel ANO1/TMEM16A suppresses tumor growth and invasion in human lung cancer. ANO1 is upregulated in different human lung cancer cell lines. Knocking-down ANO1 by small hairpin RNAs inhibited proliferation, migration and invasion of GLC82 and NCI-H520 cancel cells evaluated by CCK-8, would-healing, transwell and 3D soft agar assays. ANO1 protein is overexpressed in 77.3% cases of human lung adenocarcinoma tissues detected by immunohistochemistry. Furthermore, the tumor growth in nude mice implanted with GLC82 cells was significantly suppressed by ANO1 silencing. Taken together, our findings provide evidence that ANO1 overexpression contributes to tumor growth and invasion of lung cancer; and suppressing ANO1 overexpression may have therapeutic potential in lung cancer therapy.
Subject(s)
Adenocarcinoma/genetics , Cell Proliferation/genetics , Chloride Channels/genetics , Lung Neoplasms/genetics , Neoplasm Proteins/genetics , Adenocarcinoma/pathology , Adenocarcinoma of Lung , Animals , Anoctamin-1 , Calcium/metabolism , Cell Movement/genetics , Chloride Channels/biosynthesis , Gene Expression Regulation, Neoplastic , Gene Knockdown Techniques , Humans , Lung Neoplasms/pathology , Mice , Neoplasm Invasiveness/genetics , Neoplasm Proteins/biosynthesis , RNA, Small Interfering/genetics , Xenograft Model Antitumor AssaysABSTRACT
BACKGROUND: Insulin-like growth factor 2 mRNA binding protein 3 (IMP3) is expressed in metastatic and a subset of primary renal cell carcinoma (RCC). However, the role of IMP3 in RCC progression was poorly understood. We aim to uncover the mechanism of IMP3 in regulating clear cell RCC (CCRCC) progression and validate the prognostic significance of IMP3 in localized CCRCC. METHODS: Caki-1 cells stably overexpressing IMP3 and Achn cells with knockdown of IMP3 were analyzed for cell migration and invasion by Transwell assay. RNA-seq was used to profile gene expression in IMP3-expressing Caki-1 cells. A cohort of 469 localized CCRCC patients were examined for IMP3 expression by immunohistochemistry using tumor tissue array. RESULTS: IMP3 promoted Caki-1 cell migration and invasion, whereas knockdown of IMP3 by RNAi inhibited Achn cell migration and invasion. Enhanced IMP3 expression activated NF-кB pathway and through which, it functioned in promoting the RCC cell migration. IMP3 expression in localized CCRCC was found to be associated with higher nuclear grade, higher T stage, necrosis and sarcomatoid differentiation (p< 0.001). Enhanced IMP3 expression was correlated with shorter recurrence-free and overall survivals. Multivariable analysis validated IMP3 as an independent prognostic factor for localized CCRCC patients. CONCLUSION: IMP3 promotes RCC cell migration and invasion by activation of NF-кB pathway. IMP3 is validated to be an independent prognostic marker for localized CCRCC.
Subject(s)
Carcinoma, Renal Cell/metabolism , Carcinoma, Renal Cell/pathology , Disease Progression , Kidney Neoplasms/pathology , NF-kappa B/metabolism , RNA-Binding Proteins/metabolism , Signal Transduction , Adult , Aged , Aged, 80 and over , Biomarkers, Tumor/metabolism , Cell Line, Tumor , Cell Movement , Female , Humans , Kaplan-Meier Estimate , Kidney Neoplasms/metabolism , Male , Middle Aged , Multivariate Analysis , Neoplasm Invasiveness , Prognosis , Young AdultABSTRACT
Unconventional myosin VIIA (Myo7a) has been known to associate with hereditary deafness. Here we present a novel function of Myo7a by identifying that Myo7a directly interacts with integrin ß5 subunit and regulates cell adhesion and motility in an integrin-dependent manner. We found that Myo7a bound to the cytoplasmic tail of integrin ß5. Further, we pinpointed an integrin-binding domain at F3 of the first FERM domain and F1 of the second FERM domain. Functionally, Myo7a-induced cell adhesion and migration were mediated by integrin αvß5. These findings indicated that Myo7a interacts with integrin ß5 and selectively promotes integrin αvß5-mediated cell migration.
Subject(s)
Cell Movement , Integrin beta Chains/metabolism , Myosins/chemistry , Myosins/metabolism , Receptors, Vitronectin/metabolism , Animals , Cell Adhesion , Cell Line , Cytoplasm/metabolism , Humans , Mice , Myosin VIIa , Protein Binding , Protein Structure, TertiaryABSTRACT
Kindlin 2, as a focal adhesion protein, controls integrin activation and regulates Wnt signaling in an integrin-binding independent manner. However, the association of Kindlin 2 with cancer-related microRNAs is unknown. Here, we report that Kindlin 2 markedly downregulates the expression of miR-200 family by inducing CpG island hypermethylation. Mechanistically, Kindlin 2 forms a complex with DNMT3A in the cell nucleus and the two proteins co-occupy the promoter of miRNA-200b. Functionally, repression of miR-200b is required for Kindlin 2-induced breast cancer cell invasion and tumor formation. Our data indicate that Kindlin 2 plays a novel role in epigenetic repression of miR-200 family, a mechanism that promotes breast cancer invasion.
Subject(s)
Breast Neoplasms/pathology , Gene Silencing , Membrane Proteins/physiology , MicroRNAs/genetics , Neoplasm Proteins/physiology , Animals , Cell Line, Tumor , CpG Islands , DNA (Cytosine-5-)-Methyltransferases/physiology , DNA Methylation , DNA Methyltransferase 3A , Female , Humans , Mice , Mice, SCID , Neoplasm InvasivenessABSTRACT
Kindlin-2, as a focal adhesion protein, has been found to regulate tumor progression. However, the mechanism underlying Kindlin-2 regulation of tumor progression is largely unknown. Here, we report that Kindlin-2 regulates breast cancer cell proliferation, apoptosis and chromosomal abnormalities in both gain and loss of function assays. Functionally, overexpression of Kindlin-2 promotes tumor formation in implanted xenograft while knockdown of Kindlin-2 inhibits tumor growth in mice. Mechanistically, an array-based comparative genomic hybridization and karyotype analyses indicate that ectopic expression of Kindlin-2 leads to genome instability in breast cancer cells. Our data suggest a novel mechanism that Kindlin-2 regulates breast cancer progression by inducing genome instability.
Subject(s)
Breast Neoplasms/genetics , Breast Neoplasms/pathology , Genomic Instability/genetics , Membrane Proteins/physiology , Neoplasm Proteins/physiology , Animals , Apoptosis , Cell Cycle , Cell Line, Tumor , Cell Proliferation , Female , Humans , Membrane Proteins/analysis , Mice , Neoplasm Proteins/analysisABSTRACT
Using a Dual-View wavelength splitter, double-stained African green monkey kidney COS-7 cells, transfected with pEGFP-Myosin 15a and costained with Rhodamine-filopodia were observed based on an ICCD(intensified charge couple device) fluorescence micro-imaging systems. Total internal reflection fluorescence microscopy was used to observe the overexpression of Myosin 15a to the tips of the elongation filopodia. An approach to collecting fluorescence in two channels and avoiding spectra crosstalk was employed to observe Myosin 15a and filopodia distribution in African green monkey kidney COS-7 cells. High sensitivity TIRF technology and two channels imaging method provided a wide application in bio-medical studies.
Subject(s)
COS Cells , Microscopy, Fluorescence , Animals , Chlorocebus aethiopsABSTRACT
Resistance to anticancer drugs is often observed in prostate cancer therapy. Kindlin-2 was recently found overexpressed during cancer progression. In this study, we examined the functional role of Kindlin-2 in cisplatin-induced prostate cancer cell death. Kindlin-2 was highly expressed in the androgen-insensitive (PC-3 and DU-145), but not in the androgen-sensitive cell lines (e.g., LNCaP). Overexpression of Kindlin-2 in LNCaP protected the cells from cisplatin-induced death, while Kindlin-2 knock-down in PC-3 cells enhanced cisplatin sensitivity. Mechanistically, Kindlin-2 regulation of the anti-apoptotic Bcl-xL may explain the increased cell death in the absence of Kindlin-2. Taken together, Kindlin-2 appears to play a functional role in prostate cancer cell sensitivity to cisplatin. Targeting Kindlin-2 may therefore improve drug efficacy and reduce drug doses, and would likely be beneficial for the treatment of prostate cancer.
Subject(s)
Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Cisplatin/pharmacology , Membrane Proteins/physiology , Neoplasm Proteins/physiology , Prostatic Neoplasms/drug therapy , Cell Line, Tumor , Humans , Male , Membrane Proteins/analysis , Neoplasm Proteins/analysis , Prostatic Neoplasms/chemistry , Prostatic Neoplasms/pathology , Proto-Oncogene Proteins c-bcl-2/analysis , RNA InterferenceABSTRACT
OBJECTIVE: To confirm the nucleolar localization of telomerase-regulation associated protein-human N-acetyltransferase-like protein (hALP) and its associated functions. METHODS: Immunofluoresent staining and immunoelectron microscopy were used to detect the distribution of hALP in HeLa and Saos2 cells, and the co-localization of hALP and rDNA was analyzed by fluorescence in situ hybridization and immunofluoresence. RNAi was performed to further verify the nucleolar localization of hALP. A series of eukaryotic expression plasmids carrying various portions of hALP sequence were constructed and transiently transfected to HeLa and Saos2 cells. The expression of hALP in tumor tissues was stained by immunohistochemistry. RESULTS: hALP distributed predominantly in the nucleoli of HeLa and Saos2 cells, and colocalized with rDNA. Granular component was the precise distribution of hALP in the nucleolus under electron microscope. Nucleolar signals for hALP reduced significantly in cells transfected with hALP siRNA. The carboxy terminus of hALP including residues 549-834 was necessary for its nucleolar localization. hALP could be detected in the nucleoli of many kinds of tumor cells, including leiomyosarcoma, primitive neuroectodermal tumor, neuroblastoma, melanoma, prostatic cancer, and clear cell renal carcinoma. CONCLUSION: hALP is a nucleolar protein, and the nucleolar localization is mediated by its carboxy terminal domain, and hALP could be detected in the nucleoli of many tumor tissues, which is worthy of further investigation.