TMEM106A inhibits cell proliferation,migration, and induces apoptosis of lung cancer cells

Transmembrane protein 106A (TMEM106A) has been found to function as tumor suppressor in gastric and renal cancer. However, the role of TMEM106A in nonsmall-cell lung carcinoma (NSCLC) has not been investigated. In this study, we evaluated the expression profile of TMEM106A in NSCLC tissues and cell line, and explored the roles of TMEM106A in NSCLC cell lines. Our results showed that TMEM106A expression was significantly decreased in human NSCLC tissues. In vitro assays showed that TMEM106A expression in NSCLC cell lines was much lower than that in the bronchial epithelial cell line. Besides, overexpression of TMEM106A reduced cell proliferation, migration, and invasion, while induced cell apoptosis in NSCLC cells. TMEM106A overexpression repressed epithelial-mesenchymal transition (EMT), which was illustrated by increased E-cadherin expression and decreased the expressions of N-cadherin, and vimentin. In addition, TMEM106A overexpression suppressed the activation of phosphoinositide 3-kinase/protein kinase B/nuclear factor-κB (PI3K/Akt/NF-κB) signaling pathway in NSCLC cells. Our results indicated that TMEM106A acted as a tumor suppressor in NSCLC, and could be a therapeutic target for the management of NSCLC.     

Curcumin induces apoptosis in human breast cancer cells through p53-dependent Bax induction

The aim of this study was to determine the mechanisms of curcumin-induced human breast cancer cell apoptosis. From quantitative image analysis data showing an increase in the percentage of cells with a sub-G0/G1 DNA content, we demonstrated curcumin-induced apoptosis in the breast cancer cell line MCF-7, in which expression of wild-type p53 could be induced. Apoptosis was accompanied by an increase in p53 level as well as its DNA-binding activity followed by Bax expression at the protein level. Further experiments using p53-null MDAH041 cell as well as low and high p53-expressing TR9-7 cell, in which p53 expression is under tight control of tetracycline, established that curcumin induced apoptosis in tumor cells via a p53-dependent pathway in which Bax is the downstream effector of p53. This property of curcumin suggests that this molecule could have a possible therapeutic potential in breast cancer patients.     

A p53/CPEB2 negative feedback loop regulates renal cancer cell proliferation and migration

The tumor suppressor p53 transactivates the expression of multiple genes to exert its multifaceted functions and ultimately maintains genome stability. Thus, cancer cells develop various mechanisms to diminish p53 expression and bypass the cell cycle checkpoint. In this study, we identified the gene encoding RNAbinding protein cytoplasmic polyadenylation element-binding protein 2(CPEB2) as a p53 target. In turn,CPEB2 decreases p53 messenger RNA stability and translation to fine-tune p53 level. Specifically, we showed that CPEB2 binds the cytoplasmic polyadenylation elements in the p53 30-untranslated region, and the RNA recognition motif and zinc finger(ZF) domains of CPEB2 are required for this binding. Furthermore,we found that CPEB2 was upregulated in renal cancer tissues and promotes the renal cancer cell proliferation and migration. The oncogenic effect of CPEB2 is partially dependent on negative feedback regulation of p53. Overall, we identify a novel regulatory feedback loop between p53 and CPEB2 and demonstrate that CPEB2 promotes tumor progression by inactivating p53, suggesting that CPEB2 is a potential therapeutic target in human renal cancer.     

Lamin B2 promotes the progression of triple negative breast cancer via mediating cell proliferation and apoptosis

Triple negative breast cancer (TNBC) is a more common type of breast cancer with high distant metastasis and poor prognosis. The potential role of lamins in cancer progression has been widely revealed. However, the function of lamin B2 (LMNB2) in TNBC progression is still unclear. The present study aimed to investigate the role of LMNB2 in TNBC. The cancer genome atlas (TCGA) database analysis and immunohistochemistry (IHC) were performed to examine LMNB2 expression levels. LMNB2 short hairpin RNA plasmid or lentivirus was used to deplete the expression of LMNB2 in human TNBC cell lines including MDA-MB-468 and MDA-MB-231. Alterations in cell proliferation and apoptosis in vitro and the nude mouse tumorigenicity assay in vivo were subsequently analyzed. The human TNBC tissues shown high expression of LMNB2 according to the bioinformation analysis and IHC assays. LMNB2 expression was correlated with the clinical pathological features of TNBC patients, including pTNM stage and lymph node metastasis. Through in vitro and in vivo assays, we confirmed LMNB2 depletion suppressed the proliferation and induced the apoptosis of TNBC cells, and inhibited tumor growth of TNBC cells in mice, with the decrease in Ki67 expression or the increase in caspase-3 expression. In conclusion, LMNB2 may promote TNBC progression and could serve as a potential therapeutic target for TNBC treatment.     

Allicin induces cell cycle arrest and apoptosis of breast cancer cells in vitro via modulating the p53 pathway

Background

The tumor suppressor protein p53 is a most promising target for the development of anticancer drugs. Allicin (diallylthiosulfinate) is one of the most active components of garlic (Alliium sativum L.) and possesses a variety of health-promoting properties with pharmacological applications. However, whether allicin plays an anti-cancer role against breast cancer cells through the induction of p53-mediated apoptosis remains unknown.

Methods and results

In this study, we investigate the anti-breast cancer effect of allicin in vitro by using MCF-7 and MD-MBA-231 cells. We found that allicin reduces cell viability, induces apoptosis and cell cycle arrest in both cells. Allicin activated p53 and caspase 3 expressions in both cells but produced different effects on the expression of p53-related biomarkers. In MDA-MB-231 cells, allicin up-regulated the mRNA and protein expression of A1BG and THBS1 while down-regulated the expression of TPM4. Conversely, the mRNA and protein expression of A1BG, THBS1 and TPM4 were all reduced in MCF-7 cells. Hence, allicin induces cell cycle arrest and apoptosis in breast cancer cells through p53 activation but it effects on the expression of p53-related biomarkers were dependent upon the specific type of breast cancer involved.

Conclusions

These findings suggest that allicin induces apoptosis and regulates biomarker expression in breast cancer cell lines through modulating the p53 signaling pathway. Furthermore, our results promote the utility of allicin as compound for further studies as an anticancer drug targeting p53.

     

Metformin induces unique biological and molecular responses in triple negative breast cancer cells

Triple negative (TN) breast cancer is more frequent in women who are obese or have type II diabetes, as well as young Women of Color. These cancers do not express receptors for the steroid hormones estrogen or progesterone, or the type II receptor tyrosine kinase (RTK) Her-2 but do have upregulation of basal cytokeratins and the epidermal growth factor (EGFR). These data suggest that aberrations of glucose and fatty acid metabolism, signaling through EGFR and genetic factors may promote the development of TN cancers. The anti-type II diabetes drug metformin has been associated with a decreased incidence of breast cancer, although the specific molecular subtypes that may be reduced by metformin have not been reported. Our data indicates that metformin has unique anti-TN breast cancer effects both in vitro and in vivo. It inhibits cell proliferation (with partial S phase arrest), colony formation and induces apoptosis via activation of the intrinsic and extrinsic signaling pathways only in TN breast cancer cell lines. At the molecular level, metformin increases P-AMPK, reduces P-EGFR, EGFR, P-MAPK, P-Src, cyclin D1 and cyclin E (but not cyclin A or B, p27 or p21), and induces PARP cleavage in a dose- and time-dependent manner. These data are in stark contrast to our previously published biological and molecular effects of metformin on luminal A and B, or Her-2 type breast cancer cells. Nude mice bearing tumor xenografts of the TN line MDA-MB-231, treated with metformin, show significant reductions in tumor growth (p=0.0066) and cell proliferation (p=0.0021) as compared to untreated controls. Metformin pre-treatment, before injection of MDA-MB-231 cells, results in a significant decrease in tumor outgrowth and latency. Given the unique anti-cancer activity of metformin against TN disease, both in vitro and in vivo, it should be explored as a therapeutic agent against this aggressive form of breast cancer.     

Differentiated pre-adipocytes promote proliferation,migration and epithelial-mesenchymal transition in breast cancer cells of different p53 status

Molecular Biology Reports - Breast cancer progression and metastasis are associated with stromal cells in the tumor microenvironment. Adipocytes are the most abundant cells surrounding breast...     

抑制CD36与Nogo-B表达抑制三阴性乳腺癌细胞增殖与迁移

分化聚类36（cluster of differentiation 36,CD36）是一种位于细胞表面的膜蛋白受体,可以结合并转运脂肪酸。内质网膜蛋白4B （Nogo-B）在肝脏中调控脂肪酸代谢而影响肝癌的发展。目前并不清楚CD36和Nogo-B的相互作用是否能够影响乳腺癌细胞的增殖和迁移。本研究在三阴性乳腺癌（triple-negative breast cancer,TNBC）细胞中同时干预CD36与Nogo-B的表达来探索它们对细胞增殖与迁移的影响。结果表明在三阴性乳腺癌细胞中,单独抑制CD36或Nogo-B的表达都能够抑制细胞的增殖与迁移;同时抑制CD36与Nogo-B的表达时,这种抑制效果更加明显,且Vimentin、B细胞淋巴瘤-2（B-cell lympoma-2,BCL2）和增殖细胞核抗原（proliferating cell nuclear antigen,PCNA）的表达受到抑制。在小鼠移植瘤模型中,E0771细胞转染CD36或Nogo-B的siRNA后成瘤能力降低;同时敲减CD36和Nogo-B时,肿瘤生长速度显著减慢。机制研究发现,抑制CD36和Nogo-B表达能够抑制脂肪酸结合蛋白4（fatty acid binding protein 4,FABP4）和脂肪酸转运蛋白4（fatty acid transport protein 4,FATP4） mRNA的含量,同时CD36和Nogo-B过表达刺激的细胞增殖被FABP4的siRNA降低,预示着抑制乳腺癌细胞中CD36与Nogo-B的表达可能通过抑制脂肪酸的吸收和转运而抑制细胞的生长和迁移。此外,抑制CD36与Nogo-B的表达可激活P53-P21-Rb信号通路,参与抑制CD36与Nogo-B表达而抑制的细胞增殖与迁移。本研究证明同时抑制CD36和Nogo-B的表达能够协同抑制三阴性乳腺癌细胞的增殖和迁移,为临床抗三阴性乳腺癌药物的开发提供了新的靶点。     

IgG silencing induces apoptosis and suppresses proliferation,migration and invasion in LNCaP prostate cancer cells

Immunoglobulin G (IgG) has been implicated in the progression of various cancers. This study explored the role of IgG in the proliferation, apoptosis, cell cycle and in vitro invasive properties of LNCaP prostate cancer cells. We used IGHG1 small interfering RNA to silence IgG1 expression in LNCaP cells. The efficacy of IgG1 gene knockdown was confirmed using qPCR and western blotting. The colony formation, proliferation, migration and invasion abilities of LNCaP cells after transfection were assessed using colony-forming, flow cytometry and transwell assays. The expressions of PCNA and caspase-3 proteins in LNCaP cells after transfection were detected with immunofluorescence staining and western blotting. IgG1 silencing significantly decreased the colony formation, survival, cell cycle progression, migration and invasion of LNCaP cells (p?<?0.05). IgG1 silencing also reduced the amount of the proliferation marker PCNA and induced formation of the apoptotic marker caspase-3 (p?<?0.05). Our results show that IgG1 produced by LNCaP cells confers advantages for tumor cell survival, proliferation, migration and invasion, suggesting that IgG1 is a potential target for prostate cancer treatment.     

Inhibitor of growth 4 inhibits cell proliferation,migration, and induces apoptosis of renal cell carcinoma cells

The inhibitor of growth 4 (ING4) is known as a tumor suppressor. The expressions of ING4 were markedly reduced in human renal clear cell carcinoma (ccRCC) tissues. However, the role of ING4 in renal cell carcinoma (RCC) remains unknown. The aim of the current study was to detect the ING4 expression level and its potential role in human RCC cell lines. Our results showed that ING4 was lowly expressed in human RCC cell lines compared with that in proximal tubular cell line. Ectopic overexpression of ING4 inhibited the proliferation, migration, and invasion properties, and as well as prevented epithelial-mesenchymal transition (EMT) phenotype of RCC cells. In addition, ING4 overexpression induced cell apoptosis and autophagy in RCC cells. Furthermore, ING4 overexpression suppressed the activation of PI3K/Akt pathway in RCC cells. The activator of PI3K/Akt, insulin-like growth factor 1, abolished the effects of ING4 on RCC cells. These findings indicated that ING4 presented anticancer activity in RCC cells. The effects of ING4 on RCC cells were mediated by regulating the PI3K/Akt pathway. These findings suggested that ING4 could be used for gene therapy of RCC.     

A small-molecule activator induces ULK1-modulating autophagy-associated cell death in triple negative breast cancer

ULK1 (unc-51 like autophagy activating kinase 1) is well known to be required to initiate the macroautophagy/autophagy process, and thus activation of ULK1-modulating autophagy/autophagy-associated cell death (ACD) may be a possible therapeutic strategy in triple negative breast cancer (TNBC). Here, our integrated The Cancer Genome Atlas (TCGA) data set, tissue microarray-based analyses and multiple biologic evaluations together demonstrate a new small-molecule activator of ULK1 for better understanding of how ULK1, the mammalian homolog of yeast Atg1, as a potential drug target can regulate ACD by the ULK complex (ULK1-ATG13-RB1CC1/FIP200-ATG101), as well as other possible ULK1 interactors, including ATF3, RAD21 and CASP3/caspase3 in TNBC. Moreover, such new inspiring findings may help us discover that this activator of ULK1 (LYN-1604) with its anti-tumor activity and ACD-modulating mechanisms can be further exploited as a small-molecule candidate drug for future TNBC therapy.     

Celecoxib induces p53-PUMA pathway for apoptosis in human colorectal cancer cells

Celecoxib, a clinical non-steroidal anti-inflammatory drug, displays anticarcinogenic and chemopreventive activities in human colorectal cancers, although the mechanisms of apoptosis by celecoxib are poorly understood. The existence of functional p53 but not securin in colorectal cancer cells was higher on the induction of cytotoxicity than the p53-mutational colorectal cancer cells following celecoxib treatment. The p53-wild type HCT116 cells were more susceptible to increase ∼25% cell death than the p53-null HCT116 cells after treatment with 100 μM celecoxib for 24 h. Transfection with a small interfering RNA of p53 reduced the celecoxib-induced cytotoxicity in the RKO (p53-wild type) colorectal cancer cells. Celecoxib (80-100 μM for 24 h) significantly increased total p53 proteins and the phosphorylated p53 proteins at serine-15, -20, -46, and -392 in RKO cells. However, the phospho-p53 (serine-15, -20, and -392) proteins were presented on the nuclei of cells but the phospho-p53 (serine-46) protein was located on the cytoplasma of apoptotic cells following treatment with celecoxib. Interestingly, the p53 up-regulated modulator of apoptosis (PUMA) protein, which located on the mitochondria, was induced by celecoxib in the p53-functional colorectal cancer cells but not in the p53-mutational cells. Together, this study provides the first time that celecoxib induces the various phosphorylated sites of p53 and activates p53-PUMA pathway, which potentiates the apoptosis induction in human colorectal cancer cells.     

Abrogation of junctional adhesion molecule-A expression induces cell apoptosis and reduces breast cancer progression

Intercellular junctions promote homotypic cell to cell adhesion and transfer intracellular signals which control cell growth and apoptosis. Junctional adhesion molecule-A (JAM-A) is a transmembrane immunoglobulin located at tight junctions of normal epithelial cells of mammary ducts and glands. In the present paper we show that JAM-A acts as a survival factor for mammary carcinoma cells. JAM-A null mice expressing Polyoma Middle T under MMTV promoter develop significantly smaller mammary tumors than JAM-A positive mice. Angiogenesis and inflammatory or immune infiltrate were not statistically modified in absence of JAM-A but tumor cell apoptosis was significantly increased. Tumor cells isolated from JAM-A null mice or 4T1 cells incubated with JAM-A blocking antibodies showed reduced growth and increased apoptosis which paralleled altered junctional architecture and adhesive function. In a breast cancer clinical data set, tissue microarray data show that JAM-A expression correlates with poor prognosis. Gene expression analysis of mouse tumor samples showed a correlation between genes enriched in human G3 tumors and genes over expressed in JAM-A +/+ mammary tumors. Conversely, genes enriched in G1 human tumors correlate with genes overexpressed in JAM-A-/- tumors. We conclude that down regulation of JAM-A reduces tumor aggressive behavior by increasing cell susceptibility to apoptosis. JAM-A may be considered a negative prognostic factor and a potential therapeutic target.     

Exogenous expression of N-cadherin in breast cancer cells induces cell migration, invasion, and metastasis

E- and N-cadherin are calcium-dependent cell adhesion molecules that mediate cell-cell adhesion and also modulate cell migration and tumor invasiveness. The loss of E-cadherin-mediated adhesion has been shown to play an important role in the transition of epithelial tumors from a benign to an invasive state. However, recent evidence indicates that another member of the cadherin family, N-cadherin, is expressed in highly invasive tumor cell lines that lacked E-cadherin expression. These findings have raised the possibility that N-cadherin contributes to the invasive phenotype. To determine whether N-cadherin promotes invasion and metastasis, we transfected a weakly metastatic and E-cadherin-expressing breast cancer cell line, MCF-7, with N-cadherin and analyzed the effects on cell migration, invasion, and metastasis. Transfected cells expressed both E- and N-cadherin and exhibited homotypic cell adhesion from both molecules. In vitro, N-cadherin-expressing cells migrated more efficiently, showed an increased invasion of Matrigel, and adhered more efficiently to monolayers of endothelial cells. All cells produced low levels of the matrix metalloproteinase MMP-9, which was dramatically upregulated by treatment with FGF-2 only in N-cadherin-expressing cells. Migration and invasion of Matrigel were also greatly enhanced by this treatment. When injected into the mammary fat pad of nude mice, N-cadherin-expressing cells, but not control MCF-7 cells, metastasized widely to the liver, pancreas, salivary gland, omentum, lung, lymph nodes, and lumbar spinal muscle. The expression of both E- and N-cadherin was maintained both in the primary tumors and metastatic lesions. These results demonstrate that N-cadherin promotes motility, invasion, and metastasis even in the presence of the normally suppressive E-cadherin. The increase in MMP-9 production by N-cadherin-expressing cells in response to a growth factor may endow them with a greater ability to penetrate matrix protein barriers, while the increase in their adherence to endothelium may improve their ability to enter and exit the vasculature, two properties that may be responsible for metastasis of N-cadherin-expressing cells.