RRR-alpha-tocopheryl succinate inhibits human prostate cancer cell invasiveness

RRR-alpha-tocopheryl succinate (alpha-vitamin E succinate, VES), one of the vitamin E derivatives, can effectively inhibit the proliferation of human prostate cancer cells. However, little is known about its effect on prostate cancer cell invasive ability. Tumor metastasis is a complex process and the extracellular matrix (ECM) is the first barrier that tumor cells encounter. Therefore, we tested the effect of VES on the invasion of different prostate tumor cells, PC-3, DU-145, and LNCaP, through Matrigel, a reconstituted ECM, using an in vitro cell invasion assay. The invasion of PC-3 and DU-145 cells through Matrigel was inhibited by 20 microM VES after treating for 24 h. The condition did not alter cell survival, cell cycle, cell adhesion or cell motility. We further investigated whether the ability of VES to inhibit prostate cancer cell invasiveness was associated with its ability to inhibit the activity of matrix metalloproteinases (MMPs), the key enzymes in the proteolysis of basement membrane during invasion. PC-3 and DU-145 cells that were treated with VES showed a significant reduction in the levels of MMP-9 in the culture medium. In contrast, LNCaP cells, which did not secrete MMP-9, were poorly invasive in Matrigel and were hardly affected by treatment with VES. This is the first report suggesting that VES inhibits human prostate cancer cell invasiveness and the reduction of secreted MMP-9 activity could be one of the contributory factors, which points to the potential use of VES in the prevention and therapy of prostate cancer invasion.     

Identification of novel CHD1-associated collaborative alterations of genomic structure and functional assessment of CHD1 in prostate cancer

A clearer definition of the molecular determinants that drive the development and progression of prostate cancer (PCa) is urgently needed. Efforts to map recurrent somatic deletions in the tumor genome, especially homozygous deletions (HODs), have provided important positional information in the search for cancer-causing genes. Analyzing HODs in the tumors of 244 patients from two independent cohorts and 22 PCa xenografts using high-resolution single-nucleotide polymorphism arrays, herein we report the identification of CHD1, a chromatin remodeler, as one of the most frequently homozygously deleted genes in PCa, second only to PTEN in this regard. The HODs observed in CHD1, including deletions affecting only internal exons of CHD1, were found to completely extinguish the expression of mRNA of this gene in PCa xenografts. Loss of this chromatin remodeler in clinical specimens is significantly associated with an increased number of additional chromosomal deletions, both hemi- and homozygous, especially on 2q, 5q and 6q. Together with the deletions observed in HEK293 cells stably transfected with CHD1 small hairpin RNA, these data suggest a causal relationship. Downregulation of Chd1 in mouse prostate epithelial cells caused dramatic morphological changes indicative of increased invasiveness, but did not result in transformation. Indicating a new role of CHD1, these findings collectively suggest that distinct CHD1-associated alterations of genomic structure evolve during and are required for the development of PCa.     

Biological mechanisms in breast cancer invasiveness: relevance to preventive interventions.

Migration studies suggest that the high incidence of postmenopausal breast cancer in Western women is related mainly to epigenetic factors. Progression from ductal carcinoma in situ (DCIS) to invasive ductal carcinoma (IDC) also appears to involve environmental rather than genetic factors, and a role has been postulated for metabolic-endocrine changes related to the Western lifestyle. Protein kinase C (PKC) is important in cell signal transduction, and laboratory studies show that PKC stimulates the activities of urokinase plasminogen activator, matrix metalloproteinases and cell adhesion molecules, all of which are known to increase invasiveness in human mammary cancer cell lines. In rodents, the activity of PKC in tissue cells is enhanced by insulin, and PKC isoenzymes have been shown to stimulate the development of hyperinsulinaemic insulin resistance in rodents. Clinically, hyperinsulinaemia and the concomitant increase in circulating levels of free oestradiol and bioactive insulin-like growth factor 1 (IGF1) are each confirmed markers of high risk for breast cancer in women. Lesions of DCIS show evidence of regression with mammary involution, but it is postulated that this may be opposed by the concomitants of hyperinsulinaemic insulin resistance. The prevalence of the latter is increasing in Western populations, and a combination of high IGF1 and low IGF-binding protein 3 concentrations has been associated with the presence of DCIS lesions in premenopausal women. Measures that enhance insulin sensitivity in such women may reduce the risk of progression in DCIS lesions, and a clinical trial is proposed to test the hypothesis.     

Heparanase promotes bone destruction and invasiveness in prostate cancer

Heparanase is an endoglycosidase that plays an important role in angiogenesis and metastasis of cancer. Herein we evaluate the effect of heparanase overexpression on invasiveness and bone destruction in prostate cancer bone metastases. The human prostate cancer cell line PC-3 was stably transfected with a plasmid containing the cDNA for human heparanase or with the vector alone as a control. Overexpression of heparanase did not affect the growth of PC-3 cells, but did promote invasiveness of the cells in an in vitro assay. Both cell types were injected into the tibias of nude mice. Four weeks later, the mice were examined radiologically prior to sacrifice and samples of leg tissue were taken to investigate bone destruction and metastasis. Mice injected with PC-3 cells overexpressing heparanase had more severe bone destruction and larger, more invasive, tumors. These results demonstrate that heparanase overexpression can facilitate tumor invasion and accelerate bone destruction caused by prostate cancer bone metastasis.     

CHD1 loss sensitizes prostate cancer to DNA damaging therapy by promoting error-prone double-strand break repair

BackgroundDeletion of the chromatin remodeler chromodomain helicase DNA-binding protein 1 (CHD1) is a common genomic alteration found in human prostate cancers (PCas). CHD1 loss represents a distinct PCa subtype characterized by SPOP mutation and higher genomic instability. However, the role of CHD1 in PCa development in vivo and its clinical utility remain unclear.Patients and methodsTo study the role of CHD1 in PCa development and its loss in clinical management, we generated a genetically engineered mouse model with prostate-specific deletion of murine Chd1 as well as isogenic CHD1 wild-type and homozygous deleted human benign and PCa lines. We also developed patient-derived organoid cultures and screened patients with metastatic PCa for CHD1 loss.ResultsWe demonstrate that CHD1 loss sensitizes cells to DNA damage and causes a synthetic lethal response to DNA damaging therapy in vitro, in vivo, ex vivo, in patient-derived organoid cultures and in a patient with metastatic PCa. Mechanistically, CHD1 regulates 53BP1 stability and CHD1 loss leads to decreased error-free homologous recombination (HR) repair, which is compensated by increased error-prone non-homologous end joining (NHEJ) repair for DNA double-strand break (DSB) repair.ConclusionsOur study provides the first in vivo and in patient evidence supporting the role of CHD1 in DSB repair and in response to DNA damaging therapy. We uncover mechanistic insights that CHD1 modulates the choice between HR and NHEJ DSB repair and suggest that CHD1 loss may contribute to the genomic instability seen in this subset of PCas.     

Novel role of prostate-specific membrane antigen in suppressing prostate cancer invasiveness

Prostate-specific membrane antigen (PSMA), a type II transmembrane glycoprotein, is overexpressed in prostate cancer. PSMA is a unique cell surface marker, negatively regulated by androgen and extensively used for imaging of hormone refractory carcinomas and metastatic foci. PSMA is a carboxypeptidase with two important enzymatic functions, namely, folate hydrolase and NAALADase. PSMA also exhibits an endocytic function, in which it spontaneously recycles through endocytic vesicles. PSMA is overexpressed at various stages of prostate cancer, including androgen-sensitive and -independent disease, increased in expression with early relapse after therapy. We have used in vitro invasion assays to explore the possible role of PSMA in the metastasis of prostate cancer cells. Androgen-dependent prostate cancer lines, which express PSMA endogenously (e.g., LNCaP, MDA PCa2b, and CWR22Rv1) are less invasive compared with androgen-independent PC3 or DU145 cells, neither of which expresses PSMA. Ectopic expression of PSMA in PC3 cells reduced the invasiveness of these cells, suggesting that this reduction in the invasion capability of PSMA-expressing cells is due to PSMA expression and not to intrinsic properties of different prostate cancer cell lines. Furthermore, knockdown of PSMA expression increased invasiveness of LNCaP cells by 5-fold. Finally, expression of PSMA mutants lacking carboxypeptidase activity reduced the impact of PSMA expression on invasiveness. Thus, it seems that the enzymatic activity is associated with the effect of PSMA on invasiveness.     

Antisense therapy: recent advances and relevance to prostate cancer

Currently employed treatment options for patients with advanced and metastatic cancer such as surgery, radiation, hormone therapy, and chemotherapy are limited. In particular, the well known limitations of chemotherapy are at least in part due to a lack of specificity. The activation of dominant oncogenes and inactivation of tumor suppressor genes may represent novel targets for cancer therapy. Antisense therapy has been widely used to specifically and selectively inhibit the expression of selected genes at the messenger RNA level. Combinations of antisense oligonucleotides with chemotherapeutic agents may offer important advantages in cancer treatment. Several antisense drugs, especially oblimersen (G3139), have shown interesting results in experiments in animals, and have entered clinical trials. However, control oligonucleotides must be carefully chosen to separate antisense effects from the many potential nonspecific effects of oligonucleotides. This review summarizes the advantages and limitations of antisense therapy and its use in the treatment of androgen-independent prostate cancer.     

Opposite regulation of epithelial-to-mesenchymal transition and cell invasiveness by periostin between prostate and bladder cancer cells

We previously showed that periostin expression is downregulated in human bladder cancer tissues and that ectopic expression of periostin suppresses the invasiveness of bladder cancer cells. However, in most other human cancers studied, the expression of periostin promotes cell invasiveness. In the present study, we investigated the regulation of the epithelial-to-mesenchymal transition (EMT) and cell invasiveness by periostin in bladder and prostate cancer cell lines, and found opposite regulation of EMT and cell invasiveness by periostin. Periostin upregulated E-cadherin expression in bladder cancer cells but downregulated it in prostate cancer cells. Periostin suppressed cell invasiveness in bladder cancer cells but promoted it in prostate cancer cells. Snail, a negative regulator of E-cadherin, was upregulated by periostin in prostate cancer cells, while Twist, another negative regulator of E-cadherin, was downregulated in bladder cancer cells. The C-terminal region of periostin was sufficient for these functions in bladder cancer cells but not in prostate cancer cells. Knockdown of endogenous Snail by siRNA suppressed cell invasiveness in prostate cancer cells expressing periostin. Periostin also suppressed Akt phosphorylation in bladder cancer cells but enhanced it in prostate cancer cells. Treatment with Akt inhibitor increased E-cadherin expression and suppressed both Twist expression and cell invasiveness of bladder cancer cells. These results indicate that Akt signaling plays a role in the cell-type-dependent regulation of E-cadherin expression and cell invasiveness by periostin via Snail and Twist.     

Recurrent responses to non-small cell lung cancer brain metastases with erlotinib

We report the case of a Caucasian female never smoker with erlotinib sensitive metastatic non-small cell lung cancer in the brain. Having progressed after receiving whole brain radiotherapy, her brain metastases responded both initially and on re-treatment with erlotinib. However, her extra-cranial disease remained erlotinib-resistant throughout. This case demonstrates that brain metastases may be sensitive to erlotinib and also highlights the oligoclonal nature of non-small cell lung cancer reflected by differential tyrosine kinase inhibitor tumour sensitivity. On the basis of this case we suggest that erlotinib should be considered in the treatment paradigm for patients with intra-cranial disease and propose further study into the continued use of this drug in the situation where there is a differential response.     

沉默CHD1L对前列腺癌PC3细胞恶性生物学行为的影响及其可能机制

目的:探讨染色质解旋酶DNA结合蛋白1样基因(chromodomain helicase/ATPase DNA binding protein 1-like gene,CHD1L)对前列腺癌细胞侵袭、迁移能力的影响及其可能的作用机制.方法:采用实时荧光定量PCR技术检测前列腺癌细胞株LNCAP、PC3、DU145以及前列腺上皮细胞株RWPE-1中CHD1L mRNA表达水平;转染siRNA干扰前列腺癌PC3细胞CHD1L的表达,并用Transwell侵袭实验和划痕实验分析沉默CHD1L对前列腺癌细胞侵袭和迁移能力的影响;Western blotting 检测PC3细胞MMP-9、N-钙黏蛋白和E-钙黏蛋白的表达水平.结果:CHD1L mRNA在前列腺癌细胞中的表达水平明显高于前列腺上皮细胞(P＜0.01),其中以前列腺癌PC3细胞的表达水平最高.侵袭实验中,干扰组的穿膜细胞数明显低于阴性对照组和空白对照组[(49.67 ±6.67)vs(113.67 ±5.69)和(112.00±12.49)个,P＜0.05).划痕实验中,干扰组48 h伤口愈合率也低于阴性对照组和空白对照组[(21.27 ±3.27)％ vs(48.47±5.72)％和(49.93±3.35)％,P＜0.05].干扰组细胞MMP-9和N-钙黏蛋白表达下调,E-钙黏蛋白表达上调.结论:沉默CHD1L可降低前列腺癌PC3细胞的侵袭迁移能力,该作用可能是通过调控MMP-9和EMT相关蛋白表达实现的.     

Recurrent esophageal cancer with complete response to TS-1 chemotherapy

An 80-year-old man was admitted to our hospital for treatment of recurrent esophageal cancer in December, 2004. He was diagnosed as having esophageal cancer of stage IVa (T2N4M0) in October, 2002, and he received chemoradiotherapy (nedaplatin (CDGP)/5-fluorouracil (5-FU) total 6 course+60 Gy). Afterwards, lymph nodes recurred, and two courses of CDGP/vindesine were given. Then, the primary lesion showed a complete response (CR), and lymph nodes a partial response (PR). In December, 2004, paraesophageal lymph nodes were enlarged to the size of 7 cm. On admission, because of renal disturbance and dementia with advanced age, we chose chemotherapy with TS-1 (100 mg/body/day, three weeks of administration, then two weeks of withdrawal). He had adverse effects of hematotoxicity of grade 3, and non-hematotoxicity of grade 1. He received 6 courses of this regimen and eventually showed CR. Serum SCC was decreased from 4.7 ng/mL to 0.9 ng/mL. At present,the lesions have not recurred during the follow-up for 18 months.     

Prostate cancer antigen-1 contributes to cell survival and invasion though discoidin receptor 1 in human prostate cancer

A novel gene, prostate cancer antigen ( PCA ) -1 , was recently reported to be expressed in the prostate; however, its biological roles remain unclear. Knockdown of the PCA-1 gene by small interfering RNA transfection induced apoptosis through reducing the expression of the anti-apoptotic molecule Bcl-xl and cytoplasmic release of cytochrome c in the androgen-independent prostate cancer cell line PC3. Moreover, in vitro matrigel and in vivo chorioallantoic membrane assays showed that silencing of PCA-1 significantly downregulated discoidin receptor ( DDR ) -1 expression, resulting in suppression of cancer-cell invasion. Transfection with PCA-1 increased the levels of both Bcl-xl and DDR1, which made the cells more invasive through the upregulation of matrix metalloproteinase 9 in DU145. Interestingly, long-term culture using androgen-free medium increased the level of PCA-1 and the related expression of Bcl-xl and DDR-1 in the androgen-sensitive cancer cell line LNCaP, suggesting that PCA-1 signaling is associated with androgen independence. Immunohistochemical analysis in a series of 169 prostate carcinomas showed that PCA-1 and DDR1 were strongly expressed in prostate cancer cells, including preneoplastic lesions, but there was little or no expression in normal epithelium. Moreover, the expression of PCA-1 and DDR-1 was associated with a hormone-independent state of prostate cancer. Taken together, we propose that PCA-1–DDR-1 signaling is a new important axis involved in malignant potential prostate cancer associated with hormone-refractory status. ( Cancer Sci 2008; 99: 39–45)     

Clinical relevance of galectin-1 expression in non-small cell lung cancer patients

Background

Identification of biomarkers in lung cancer, a leading cause of cancer-related mortality, has a meaningful clinical relevance in the quest of novel prognostic factors and therapeutic targets. The glycan-binding protein galectin-1 (Gal-1) modulates tumor progression by mediating cell–cell and cell–extracellular matrix interactions, as well as angiogenesis and tumor immune-escape. Previous works reported the expression of Gal-1 in lung cancer, although its clinical significance remains uncertain.

Objective

To assess the clinicopathologic relevance and prognostic value of Gal-1 expression in a cohort of 103 Stage I–III non-small cell lung cancer (NSCLC) patients.

Methods

Gal-1 expression was determined by immunohistochemistry in tumor tissue samples. The percentage of immunoreactive tumor cells and stroma, as well as the presence of blood vessels with positively stained endothelium in the tumor and surrounding normal tissue, were recorded. Results were correlated with the clinicopathologic factors of the patients (Spearman's rank correlation coefficient, chi-square test) and overall survival by univariate (Kaplan Meier) and multivariate analyses (Cox regression hazard model).

Results

We did not observe significant associations between Gal-1 expression and relevant clinicopathologic features at diagnosis of NSCLC. However, Kaplan Meier analysis revealed a significant association between Gal-1 expression and overall survival, when Gal-1 expression was analyzed on tumor cells alone (“tumor cell percentage”) or when an integrated score accounting for tumor cell as well as stromal expression of Gal-1 (“total score”) was assessed. Patients showing high Gal-1 expression evidenced a poorer clinical outcome. Furthermore, “total score” remained significantly associated with survival by multivariate Cox regression analysis in the whole cohort of patients, even when controlling for the classical predictors and prognostic factors of NSCLC.

Conclusion

We conclude that Gal-1 expression may be a useful biomarker for better prediction of the clinical outcome and management of NSCLC patients.