Biomedical subjects

Mingxin Che

Publications and source records attributed to Mingxin Che.

At least 19 recordsLinked to original sources

PubMed2007

In vitro and in vivo molecular evidence of genistein action in augmenting the efficacy of cisplatin in pancreatic cancer.

We recently reported the potential of genistein in augmenting gemcitabine-induced killing of pancreatic cancer (Banerjee, S. et al., Cancer Research 2005;65:9064-72). Since cis-diaminedichloroplatinum (II) (cisplatin) is widely used against solid tumors, we further investigated whether genistein pretreatment could be used as a novel strategy for cisplatin-induced killing of pancreatic cancer cells in vitro and enhanced antitumor activity in vivo. Our in vitro results showed that pretreatment of cells with genistein followed by cisplatin resulted in significant loss of cell viability and potentiated apoptosis irrespective of the metastatic ability of cells. Mechanistically, genistein augmented cisplatin induced killing by down regulating transcription factor-NF-kappaB and anti-apoptotic Akt expression. NF-kappaB was found upregulated when pancreatic cancer cells were exposed to cisplatin, suggesting the potential mechanism of acquired chemo-resistance. In addition, we also showed, for the first time, that genistein in combination with cisplatin is more effective antitumor agent in our orthotopic tumor model. But most importantly, our data also showed that a specific target, such as NF-kappaB, was inactivated in animal tumors treated with genistein and cisplatin. Immunohistochemical data showed reduced staining for phospho-p65, Bcl-xL and MMP-9 in treated tumors compared to control tumors, but the lowest activity was seen in the combination group. These results provide strong molecular in vivo evidence in support of our hypothesis that inactivation of the NF-kappaB signaling pathway by genistein results in the chemo-sensitization of pancreatic tumors to cisplatin, which is likely to be an important and novel strategy for the treatment of pancreatic cancer.

Animals↗

PubMed2007

Progression of renal cell carcinoma is inhibited by genistein and radiation in an orthotopic model.

BACKGROUND: We have previously reported the potentiation of radiotherapy by the soy isoflavone genistein for prostate cancer using prostate tumor cells in vitro and orthotopic prostate tumor models in vivo. However, when genistein was used as single therapy in animal models, it promoted metastasis to regional para-aortic lymph nodes. To clarify whether these intriguing adverse effects of genistein are intrinsic to the orthotopic prostate tumor model, or these results could also be recapitulated in another model, we used the orthotopic metastatic KCI-18 renal cell carcinoma (RCC) model established in our laboratory. METHODS: The KCI-18 RCC cell line was generated from a patient with papillary renal cell carcinoma. Following orthotopic renal implantation of KCI-18 RCC cells and serial in vivo kidney passages in nude mice, we have established a reliable and predictable metastatic RCC tumor model. Mice bearing established kidney tumors were treated with genistein combined with kidney tumor irradiation. The effect of the therapy was assessed on the primary tumor and metastases to various organs. RESULTS: In this experimental model, the karyotype and histological characteristics of the human primary tumor are preserved. Tumor cells metastasize from the primary renal tumor to the lungs, liver and mesentery mimicking the progression of RCC in humans. Treatment of established kidney tumors with genistein demonstrated a tendency to stimulate the growth of the primary kidney tumor and increase the incidence of metastasis to the mesentery lining the bowel. In contrast, when given in conjunction with kidney tumor irradiation, genistein significantly inhibited the growth and progression of established kidney tumors. These findings confirm the potentiation of radiotherapy by genistein in the orthotopic RCC model as previously shown in orthotopic models of prostate cancer. CONCLUSION: Our studies in both RCC and prostate tumor models demonstrate that the combination of genistein with primary tumor irradiation is a more effective and safer therapeutic approach as the tumor growth and progression are inhibited both in the primary and metastatic sites.

Animals↗

PubMed2006

Antitumor activity of epidermal growth factor receptor-related protein is mediated by inactivation of ErbB receptors and nuclear factor-kappaB in pancreatic cancer.

The erbB family of receptor tyrosine kinases plays critical roles in human cancers, including pancreatic cancer. Discovering a specific agent, which targets multiple members of the erbB family, would be important in pancreatic cancer therapy. Recently, we isolated a novel negative regulator of epidermal growth factor receptor (EGFR), termed EGFR-related protein (ERRP), whose expression attenuates EGFR activation. In the current study, we examined the effects of recombinant ERRP on the growth and ligand-induced activation of multiple members of erbB family in three pancreatic cancer cell lines that express varying levels of EGFR and other member(s) of its family, specifically HER-2. Additionally, we compared the growth inhibitory effect of ERRP with that of Erbitux or Herceptin. Our results showed that ERRP is most effective in inhibiting proliferation of BxPC-3, HPAC, and PANC-1 pancreatic cancer cells. ERRP also inhibited ligand-induced activation of EGFR, HER-2, and HER-3 (ErbB3). In contrast, Erbitux and Herceptin only partially or modestly inhibited activation of EGFR, HER-2, and HER-3. Most importantly, ERRP was found to inhibit pancreatic tumor growth in a severe combined immunodeficient mouse xenograft model. The antitumor activity of ERRP correlates well with tumor differentiation and down-regulation of nuclear factor-kappaB activity. In summary, our results suggest that ERRP is an effective pan-erbB inhibitor, which could be a potential therapeutic agent for pancreatic cancers expressing different levels and subclasses of erbB family of proteins.

Cell Differentiation↗

PubMed2006

Prostate cancer treatment is enhanced by genistein in vitro and in vivo in a syngeneic orthotopic tumor model.

Pretreatment with genistein, a bioactive component of soy isoflavones, potentiated cell killing induced by radiation in human PC-3 prostate cancer cells in vitro. Using an orthotopic xenograft in nude mice, we demonstrated that genistein combined with prostate tumor irradiation caused greater inhibition of primary tumor growth and increased control of spontaneous metastasis to para-aortic lymph nodes, increasing mouse survival. Paradoxically, treatment with genistein alone increased metastasis to lymph nodes. This observation is of concern in relation to soy-based clinical trials for cancer patients. To address whether this observation is because nude mice have an impaired immune system, these studies were repeated in orthotopic RM-9 prostate tumors in syngeneic C57BL/6 mice. The combination of genistein with radiation in this model also caused a greater inhibition of primary tumor growth and spontaneous metastasis to regional para-aortic lymph nodes, whereas treatment with genistein alone showed a trend to increased lymph node metastasis. Data from the syngeneic and xenograft models are comparable and indicate that the combination of genistein with radiotherapy is more effective and safer for prostate cancer treatment than genistein alone, which promotes metastatic spread to regional lymph nodes.

Animals↗

PubMed2005

Expression of cyclooxygenase-2 in advanced stage ovarian serous carcinoma: correlation with tumor cell proliferation, apoptosis, angiogenesis, and survival.

OBJECTIVE: Cyclo-oxygenase-2 seems to be involved at various steps in the processes of tumor progression. The objective of this study was to examine the relationship between cyclo-oxygenase-2 expression and tumor proliferation, apoptosis and angiogenesis in patients with advanced stage high-grade ovarian carcinoma. STUDY DESIGN: Specimens from 118 patients with high-grade and advanced stage (III, IV) serous ovarian carcinoma were evaluated by immunohistochemistry for cyclo-oxygenase-2, Ki-67, vascular endothelial growth factor, and bcl-2 expression. Tumor microvessel density was assessed with CD34 immunostaining. We investigated the relationships between cyclo-oxygenase-2 expression and clinicopathologic characteristics, tumor angiogenesis (tumor microvessel density and vascular endothelial growth factor expression), and tumor proliferation and apoptosis. The effect of cyclooxygenase-2 expression on patient survival was determined. RESULTS: There was a significant positive correlation between cyclo-oxygenase-2 expression in tumor cells and markers of tumor proliferation and angiogenesis. In univariate survival analysis, high cyclo-oxygenase-2 and high Ki-67 expression showed a significant impact of on patient survival (P < .001). In multivariate regression analysis, only Ki-67 expression retained its significance as an independent poor prognostic factor (death hazard ratio, 2.0; 95% CI, 1.2-3.3; P < .001). CONCLUSION: Expression of cyclo-oxygenase-2 correlates with tumor proliferation and tumor angiogenesis but not with apoptotic markers (bcl-2 expression) in high-grade, advanced-stage serous ovarian carcinoma.

Antigens, CD34↗

PubMed2005

Handling and reporting of tumor-containing kidney specimens.

The pathologic features of RCC are the most valuable factors in predicting the prognosis and for planning surveillance and treatment protocols. Urologists and pathologists should optimize approaches in handling tumor-containing kidney specimens to allow for the best evaluation and reporting of such specimens. A pathologic report of a tumor-containing kidney specimen should include all established or potential prognostic factors, especially tumor types, size, grade, information for pathologic staging, and status of the surgical margin.

Biopsy, Needle↗

PubMed2005

Clear cell renal cell carcinoma.

Clear cell RCC is the most common type of RCC that occurs in adults. It has the worst prognosis among the common epithelial tumors of the kidney. Histologically, a wide range of morphologic patterns can be encountered. Those cases with a multi-locular cystic architecture are considered to be a distinct subtype because of the clinicopathologic features.

Adenocarcinoma, Clear Cell↗

PubMed2005

Matrix metalloproteinase activity and osteoclasts in experimental prostate cancer bone metastasis tissue.

Previously, we and others showed that broad spectrum pharmaceutical inhibition of matrix metalloproteinase (MMP) activity reduces intraosseous tumor burden and bone degradation in animal models of bone metastasis. Herein, we used specific assays to measure net enzymatic activities of individual MMPs during colonization of bone by prostate cancer cells. PC3 cells were injected into the marrow of human fetal femurs previously implanted in SCID mice. Net MMP-9 activity in bone tissues peaked 2 weeks after injection, coinciding with a wave of osteoclast recruitment. In contrast, MMP-2 and MT1-MMP activity did not change. In vitro, co-culture of PC3 cells with bone tissue led to activation of pro-MMP-9 and increases in secreted net MMP-9 activity. Activation of pro-MMP-9 was prevented by metalloprotease inhibitors but not by inhibitors of other classes of proteases. Ribozyme suppression of MMP-9 expression in PC3 cells did not affect pro-MMP-9 activation or net MMP-9 activity and did not affect the phenotype of bone tumors. siRNA targeting of MMP-9 expression in preosteoclasts in vitro demonstrated that tumor-induced preosteoclast motility was dependent on MMP-9 expression. These data suggest that osteoclast-derived MMP-9 may represent a potential therapeutic target in bone metastasis and provide a rationale for the development of MMP-9-specific inhibitors.

Animals↗

PubMed2005

Curative antitumor immune response is optimal with tumor irradiation followed by genetic induction of major histocompatibility complex class I and class II molecules and suppression of Ii protein.

Transfecting genes into tumors, to upregulate major histocompatibility complex (MHC) class I and class II molecules and inhibit MHC class II associated invariant chain (Ii), induces a potent anti-tumor immune response when preceded by tumor irradiation, in murine RM-9 prostate carcinoma. The transfected genes are cDNA plasmids for interferon-gamma (pIFN-gamma), MHC class II transactivator (pCIITA), an Ii reverse gene construct (pIi-RGC), and a subtherapeutic dose of adjuvant IL-2 (pIL-2). Responding mice rejected challenge with parental tumor and demonstrated tumor-specific cytotoxic T lymphocytes (CTLs). We have extended our investigation to determine the relative roles of each one of the four plasmids pIFN-gamma, pCIITA, pIi-RGC, and pIL-2 in conjunction with radiation for the induction of a curative immune response. Upregulation of MHC class I with pIFN-gamma or class II with pCIITA, separately, does not lead to a complete response even if supplemented with pIL-2 or pIi-RGC. An optimal and specific antitumor response is achieved in more than 50% of the mice when, after tumor irradiation, tumor cells are converted in situ to a MHC class I+/class II+/Ii- phenotype with pIFN-gamma, pCIITA, pIi-RGC, and pIL-2. We demonstrate further that both CD4+ helper T cells and CD8+ cytotoxic T cells are essential for induction of an antitumor response because in vivo depletion of either subset abrogates the response. The radiation contributes to the gene therapy by causing tumor debulking and increasing the permeability of tumors to infiltration of inflammatory cells.

Animals↗

PubMed2005

A proposal for a new and more practical grading scheme for pancreatic ductal adenocarcinoma.

There is no uniformly applied grading system for pancreatic ductal adenocarcinoma (DA). The scheme advocated by the WHO is essentially that of Kloppel et al, and is based on the "highest grade" focus. Although it is precise with good prognostic value, it is unfortunately not widely applied, largely because of the lack of recognition and partly because of its complex nature (interpretation of multiple parameters). Furthermore, it is fundamentally different from the one used in Japan, which evaluates the overall pattern. To establish a more widely applicable, practical, and clinically relevant grading system, a scheme similar to Gleason's scoring system was developed and tested on 112 cases of resected pancreatic DA and was compared with the WHO system. In the grading system devised, patterns (P) of infiltration were classified as follows: P1, well-defined glands with easily discernible contours; P2, fused or poorly formed glands with ill-defined contours; P3, nonglandular patterns. A score was then obtained by the summation of the predominant and the secondary patterns. Scores < or =3 (at least some well-formed glands and no nonglandular pattern) was graded as G1, 4 as G2, and > or =5 (at least some nonglandular patterns and no well-formed glandular pattern) as G3. Seventy-three percent of the cases displayed mixed patterns, with disparate patterns (P1 with P3) in 13%, confirming the high degree of heterogeneity of DA. There was a significant correlation between grade and survival, better than the correlation between survival and either the major or minor patterns evaluated separately. The median survival for G1, G2, and G3 were 22, 14, and 8 months; 1-year survival 68%, 44%, and 33%; 2-year was 67%, 11%, and 0%; and 3-year was 23%, 4%, and 0%, respectively (P = 0.0019). In a multivariate analysis, correlating survival with grade, tumor size, and lymph node status, the grade was the strongest independent predictor of survival. Odds ratio of dying of disease were 3.56 (P < 0.0001) in G3 versus G1, 1.79 (P = 0.058) in G2 versus G1, and 1.98 (P = 0.03) in G3 versus G2. Compared with this, the same odds ratio were 1.17 (P = 0.01) in tumors >2 cm versus < or =2 cm and 1.78 (P = 0.01) in cases with positive versus negative lymph nodes. The WHO grading scheme was not found to have as good a correlation with survival in this study, with WHO grade 2 showing a better survival than 1. The reproducibility of both the proposed grading system and that of WHO were found to be moderately good (with kappa values of 0.43 and 0.44, respectively), when 32 slides of DA were graded by four independent observers. The grading scheme for pancreatobiliary adenocarcinoma proposed here is highly applicable because it is practical and readily adoptable. It reflects biologic characteristics of ductal carcinoma (prominent tubule formation and tumor heterogeneity). Most importantly, it is clinically relevant with good prognostic value. Lastly, it is also applicable for use in research, by utilizing "patterns," even in small specimens like microarrays or biopsies.

Adult↗

PubMed2004

Differential expression of thromboxane synthase in prostate carcinoma: role in tumor cell motility.

Arachidonic acid metabolism through cyclooxygenase, lipoxygenase, or P-450 epoxygenase pathways can generate a variety of eicosanoids. Thromboxane synthase (TxS) metabolizes the cyclooxygenase product, prostanglandin H(2), into thromboxane A(2) (TXA(2)), which can cause vessel constriction, platelet activation, and aggregation. Here we demonstrate that human prostate cancer (PCa) cells express enzymatically active TxS and that this enzyme is involved in cell motility. In human PCa cell lines, PC-3, PC-3M, and ML-2 cells expressed higher levels of TxS than normal prostate epithelial cells or other established PCa cell lines such as DU145, LNCaP, or PPC-1. We cloned and sequenced the full-length TxS cDNA from PC-3 cells and found two changes in the amino acid residues. Immunohistochemical analysis of tumor specimens revealed that expression of TxS is weak or absent in normal differentiated luminal, or secretory cells, significantly elevated in less differentiated or advanced prostate tumors, and markedly increased in tumors with perineural invasion. TxS expressed in PC-3 cells was enzymatically active and susceptible to carboxyheptal imidazole, an inhibitor of TxS. The biosynthesis of TXA(2) in PC-3 cells was dependent on COX-2, and to a lesser extent, COX-1. Treatment of PC-3 cells with a COX-1 selective inhibitor, piroxicam, reduced TXA(2) synthesis by approximately 40%, while the COX-2 specific inhibitor NS398 reduced TXA(2) production by approximately 80%. Inhibition of TxS activity or blockade of TXA(2) function reduced PC-3 cell migration on fibronectin, while having minimal effects on cell cycle progression or survival. Finally, increased expression of TxS in DU145 cells increased cell motility. Our data suggest that human PCa cells express TxS and that this enzyme may contribute to PCa progression through modulating cell motility.

Amino Acid Sequence↗

PubMed2004

Tumor irradiation followed by intratumoral cytokine gene therapy for murine renal adenocarcinoma.

To circumvent the toxicity caused by systemic injection of cytokines, cytokine cDNA genes encoding the human interleukin IL-2 cDNA (Ad-IL-2) and murine interferon IFN-gamma gene (Ad- IFN-gamma) were inserted into adenoviral vectors. These constructs were used for intratumoral gene therapy of murine renal adenocarcinoma Renca tumors. Treatment with three doses of Ad-IL-2 or Ad- IFN-gamma, given a day apart, was more effective than single-dose gene therapy. We found that tumor irradiation enhanced the therapeutic efficacy of Ad-IL-2 and Ad-IFN-gamma intratumoral gene therapy. Tumor irradiation, administered 1 day prior to three doses of Ad-IL-2 treatment, was more effective than radiation or Ad-IL-2 alone, resulting in tumor growth arrest in all mice, increased survival and a consistent increase in complete tumor regression response rate. Complete responders rejected Renca tumor challenge and demonstrated specific cytotoxic T-cell activity, indicative of specific tumor immunity. The effect of radiation combined with three doses of Ad-IFN-gamma was less pronounced and did not lead to tumor immunity. Histological observations showed that irradiation of the tumor prior to gene therapy increased tumor destruction and inflammatory infiltrates in the tumor nodules. These findings demonstrate that tumor irradiation improves the efficacy of Ad-IL-2 gene therapy for induction of antitumor immune response.

Adenoviridae↗

PubMed2004

Disseminated malignant solitary fibrous tumor of the pleura.

Solitary fibrous tumor (SFT) of the pleura typically forms a localized pleura-based mass, and most are benign. A rare case of disseminated malignant SFT of the pleura is reported. The patient was a 71-year-old man who presented with complaints of shortness of breath to his primary care physician. A diagnosis of malignant mesothelioma was suspected, based on clinical, radiological and needle biopsy findings. He was referred to our institution for surgery. An extrapleural pneumonectomy, encompassing all pleural masses, was performed. Gross examination of the resected specimen was remarkable for numerous masses, ranging in size from 0.2 to 13.5 cm, covering the majority of the visceral pleura. Histologically, the tumor was composed of short spindle cells admixed with variable proportions of collagenous stroma. There were great intra- and intertumoral heterogeneity in tumor growth pattern, cellularity, pleomorphism and mitoses. Histologically malignant areas were present in all of the masses examined. The neoplastic cells were diffusely and intensely positive for bcl-2. Most tumor cells were also strongly stained for CD34 and CD99. Staining for cytokeratin was negative. The tumor also revealed p53 over-expression. Thus, the histological and immunohistochemical features of the tumor were consistent with a disseminated malignant SFT. This report shows that SFT rarely presents with disseminated pleural involvement, and a panel with CD34, bcl-2 and cytokeratin are valuable for differentiating SFT from malignant mesothelioma and other malignant spindle cell neoplasms of the pleura.

Aged↗

PubMed2004

Genistein potentiates inhibition of tumor growth by radiation in a prostate cancer orthotopic model.

OBJECTIVE: We have shown previously that pretreatment with genistein potentiated cell killing induced by radiation in human PC-3 prostate carcinoma cell line in vitro. We tested this approach in vivo using an orthotopic prostate carcinoma model of PC-3 cells in nude mice. METHODS: Established prostate tumors were pretreated with p.o. genistein at a dose of 5 mg/d for 2 days followed by tumor irradiation with 5 Gy photons. One day after radiation, genistein was resumed and given every other day for 4 weeks. RESULTS: Genistein combined with radiation caused a significantly greater inhibition of primary tumor growth (87%) compared with genistein (30%) or radiation (73%) alone. The number of metastatic lymph nodes was also significantly decreased following genistein and radiation. Paradoxically, genistein alone increased the size of lymph nodes associated with heavy tumor infiltration. Genistein-treated prostate tumors were large with necrosis, apoptotic cells, and giant cells and have a lower proliferation index than in control tumors. Following radiation, areas of tumor destruction replaced by fibrotic tissue and inflammatory cells as well as giant cells were observed, which are typical of radiation effect. After radiation and genistein treatment, an increase in giant cells, apoptosis, inflammatory cells, and fibrosis was observed with decreased tumor cell proliferation consistent with increased tumor cell destruction. Long-term therapy with genistein after prostate tumor irradiation significantly increased survival. CONCLUSIONS: Genistein combined with prostate tumor irradiation led to a greater control of the growth of the primary tumor and metastasis to lymph nodes than genistein or radiation alone, resulting in greater survival.

Animals↗

PubMed2003

The effect of cyclooxygenase-2 expression on tumor vascularity in advanced stage ovarian serous carcinoma.

BACKGROUND: Cyclooxygenase-2 (COX-2) seems to be involved at various steps in the processes of malignant transformation and tumor progression. Investigations have shown that COX-2 overexpression is associated with increased proliferation, reduced apoptosis, and angiogenesis. METHODS: Specimens from 125 patients with high-grade, advanced-stage (Stage III-IV) serous ovarian carcinoma were evaluated by immunohistochemistry for COX-2, p53, bcl-2, epidermal growth factor receptor (EGFR), and Her-2/neu expression and for CD34-stained microvessel density (MVD). Statistical analysis was performed to investigate the correlations between COX-2 expression and 1) clinicopathologic characteristics, 2) tumor MVD, and 3) expression of other molecular markers. The effect of COX-2 expression on survival was determined using survival analysis. RESULTS: Increased COX-2 expression was significantly correlated with tumor MVD (Spearman rank correlation test: r = 0.41; P < 0.001). There was no association observed between COX-2 expression and expression levels of EGFR, Her-2/neu, bcl-2, or p53. Patients who had tumors that showed high COX-2 expression had a worse prognosis compared with patients who had tumors with low expression (death hazard ratio, 2.0; 95% confidence interval, 1.2-3.5; P < 0.001). A multivariate analysis revealed that COX-2 expression was the strongest predictor of survival among the different prognostic factors analyzed. CONCLUSIONS: The current study demonstrated that COX-2 expression was correlated significantly with survival in patients with high-grade, high-stage serous ovarian carcinoma. Expression of COX-2 also was correlated with tumor angiogenesis but not with EGFR, Her-2/neu, or p53 expression. In addition to their prognostic significance, a better understanding of the biology of these molecular changes may help identify new targets for therapy in patients with ovarian carcinoma.

Adult↗

PubMed2003

Responsiveness of experimental prostate carcinoma bone tumors to neutron or photon radiation combined with cytokine therapy.

PURPOSE: To improve the outcome of radiotherapy for prostate carcinoma bone tumors, we investigated bone tumor irradiation with photons or neutrons followed by interleukin 2 (IL-2) therapy in a tumor model. METHODS AND MATERIALS: Implantation of PC-3 cells in nude mouse femur cavity induced a bone tumor that progressed to the formation of a palpable tumor, at the hip joint, by Day 20. Established bone tumors were irradiated with photons or neutrons, and a day later, mice were treated with IL-2 therapy for 3 weekly cycles. RESULTS: PC-3 bone tumors responded to radiation with photons or neutrons in a dose-dependent manner. Combination of photon or neutron radiation with IL-2 therapy increased tumor growth delay, compared to that with photons or neutrons alone. Radiation alone or combined with IL-2 significantly increased mouse survival compared to that with IL-2 or no treatment. After combined therapy, a complete inhibition of bone tumor growth was observed in 45% to 50% of the mice. Histologically, the combined therapy resulted in greater tumor destruction associated with fibrosis, new bone formation, and inflammatory infiltrates than that observed with each modality alone. CONCLUSIONS: The efficacy of tumor irradiation with neutrons or photons was enhanced by IL-2 therapy for the treatment of prostate carcinoma bone tumors.

Animals↗

PubMed2003

Maspin expression inhibits osteolysis, tumor growth, and angiogenesis in a model of prostate cancer bone metastasis.

Emerging evidence indicates that tumor-associated proteolytic remodeling of bone matrix may underlie the capacity of tumor cells to colonize and survive in the bone microenvironment. Of particular importance, urokinase-type plasminogen activator (uPA) has been shown to correlate with human prostate cancer (PC) metastasis. The importance of this protease may be related to its ability to initiate a proteolytic cascade, leading to the activation of multiple proteases and growth factors. Previously, we showed that maspin, a serine protease inhibitor, specifically inhibits PC-associated uPA and PC cell invasion and motility in vitro. In this article, we showed that maspin-expressing transfectant cells derived from PC cell line DU145 were inhibited in in vitro extracellular matrix and collagen degradation assays. To test the effect of tumor-associated maspin on PC-induced bone matrix remodeling and tumor growth, we injected the maspin-transfected DU145 cells into human fetal bone fragments, which were previously implanted in immunodeficient mice. These studies showed that maspin expression decreased tumor growth, reduced osteolysis, and decreased angiogenesis. Furthermore, the maspin-expressing tumors contained significant fibrosis and collagen staining, and exhibited a more glandular organization. These data represent evidence that maspin inhibits PC-induced bone matrix remodeling and induces PC glandular redifferentiation. These results support our current working hypothesis that maspin exerts its tumor suppressive role, at least in part, by blocking the pericellular uPA system and suggest that maspin may offer an opportunity to improve therapeutic intervention of bone metastasis.

Animals↗

PubMed2003

Quantification of G250 mRNA expression in renal epithelial neoplasms by real-time reverse transcription-PCR of dissected tissue from paraffin sections.

AIM: Renal cell carcinoma (RCC) represents the most common malignant tumour in the kidney and is resistant to conventional therapies. G250 is a tumour-associated antigen and is expressed mainly in clear cell RCC. It is a potential therapeutic target as well as a diagnostic marker for RCC. Previous studies relating to G250 protein or G250 mRNA expression in RCC using human tissue have largely been limited to immunohistochemical or conventional RT-PCR approaches that lack reproducibility, are subject to observer bias and are at most semi-quantitative. In this study, we evaluated the feasibility of using real-time RT-PCR in quantifying G250 mRNA expression using tissue dissected from paraffin sections of renal epithelial neoplasms. Using this approach, we performed a preliminary study investigating the relationship between G250 expression and tumor behavior in clear cell RCC. METHODS: A total of 53 radical nephrectomy specimens with renal epithelial neoplasms (nine oncocytoma, seven chromophobe RCC, four papillary RCC and 33 clear cell RCC) were included in this study. SYBR Green real-time RT-PCR was performed using the ABI PRISM 7700 Sequence Detection System. A TATA box-binding protein (TBP) was used as an endogenous reference gene. RESULTS: Our study showed that real-time RT-PCR is a reliable approach in quantifying G250 mRNA expression using paraffin sections. Using this methodology, G250 mRNA was detected in all of the clear cell RCCs, but none of the other types of tumours studied or in normal kidney tissue. Our study also suggested that the expression of G250 mRNA might correlate with tumour stage and overall survival. CONCLUSION: Among common renal epithelial neoplasms, G250 is a specific marker for clear cell RCC. Quantification of G250 mRNA expression by real-time RT-PCR using paraffin sections is a feasible approach for future clinical studies in evaluating the prognostic and predictive value of G250 in clear cell RCC.

Antigens, Neoplasm↗