An in vivo mouse reporter gene (human secreted alkaline phosphatase) model to monitor ovarian tumor growth and response to therapeutics

CRISPR-Cas9 immune-evasive hESCs are rejected following transplantation into immunocompetent mice

Although current stem cell therapies exhibit promising potential, the extended process of employing autologous cells and the necessity for donor-host matching to avert the rejection of transplanted cells significantly limit the widespread applicability of these treatments. It would be highly advantageous to generate a pluripotent universal donor stem cell line that is immune-evasive and, therefore, not restricted by the individual's immune system, enabling unlimited application within cell replacement therapies. Before such immune-evasive stem cells can be moved forward to clinical trials, in vivo testing via transplantation experiments in immune-competent animals would be a favorable approach preceding preclinical testing. By using human stem cells in immune competent animals, results will be more translatable to a clinical setting, as no parts of the immune system have been altered, although in a xenogeneic setting. In this way, immune evasiveness, cell survival, and unwanted proliferative effects can be assessed before clinical trials in humans. The current study presents the generation and characterization of three human embryonic stem cell lines (hESCs) for xenogeneic transplantation in immune-competent mice. The major histocompatibility complexes I- and II-encoding genes, B2M and CIITA, have been deleted from the hESCs using CRISPR-Cas9-targeted gene replacement strategies and knockout. B2M was knocked out by the insertion of murine CD47. Human-secreted embryonic alkaline phosphatase (hSEAP) was inserted in a safe harbor site to track cells in vivo. The edited hESCs maintained their pluripotency, karyotypic normality, and stable expression of murine CD47 and hSEAP in vitro. In vivo transplantation of hESCs into immune-competent BALB/c mice was successfully monitored by measuring hSEAP in blood samples. Nevertheless, transplantation of immune-evasive hESCs resulted in complete rejection within 11 days, with clear immune infiltration of T-cells on day 8. Our results reveal that knockout of B2M and CIITA together with species-specific expression of CD47 are insufficient to prevent rejection in an immune-competent and xenogeneic context.

Preoperative alkaline phosphatase-to-platelet count ratio as a prognostic factor for hepatocellular carcinoma with microvascular invasion

OBJECTIVES

The association between platelet status and hepatocellular carcinoma (HCC) prognoses remains controversial. Herein, we aimed to clarify the prognostic value of multiple platelet-related biomarkers, including platelet count, platelet/lymphocyte ratio (PLR), aspartate aminotransferase to platelet ratio index (APRI), and alkaline phosphatase-to-platelet count ratio index (APPRI) in HCC with microvascular invasion (MVI) after curative resection or liver transplantation.

MATERIALS AND METHODS

A retrospective review of 169 patients with solitary HCC and MVI who underwent resection or liver transplantation between January 2015 and December 2018 was conducted. Preoperative clinical, laboratory, pathologic, and imaging data were collected and analyzed. Overall survival (OS) and disease-free survival (DFS) were defined as the clinical endpoints. Univariate and multivariate Cox proportional hazards regression analyses were conducted to investigate potential predictors of DFS and OS.

RESULTS

Multivariate Cox regression analyses revealed that maximum tumor diameter, poor cell differentiation, and APPRI were independent predictors of DFS; while poor cell differentiation, APRI, APPRI, prothrombin time, and alpha-fetoprotein were independent prognostic factors for OS. The 1-, 3-, and 5-year DFS rates were 66.90%, 48.40%, and 37.40% for patients with APPRI ≤0.74 and 40.40%, 24.20%,and 24.20% for patients with APPRI>0.74. The corresponding rates of OS over 1, 3, and 5 years were 92.40%, 88.10% and 77.70%, and 72.30%, 38.20%, and 19.10%, respectively. The DFS and OS rates of patients whose APPRI was more than 0.74 were substantially lower than those of patients whose APPRI was less than or equal to 0.74 (p = 0.002 and p < 0.001, respectively).

CONCLUSION

Elevated preoperative APPRI is a noninvasive, simple, and easily assessable parameter linked to poor prognosis in individuals with single HCC and MVI after resection or liver transplantation.

Prognostic Value of ALP and LDH in Periampullary Carcinoma Patients Undergoing Surgery

OBJECTIVE

Conversion of normal cells to cancer cells is often accompanied by abnormal synthesis of serum enzymes. Both alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) have been reported to have prognostic value in a variety of malignancies. The aim of this study was to investigate the effect of preoperative serum ALP and LDH levels on the prognosis of patients with periampullary carcinoma who underwent pancreatoduodenectomy (PD).

METHODS

According to the preoperative ALP or LDH values, 856 cancer patients receiving PD treatment from January 2001 to January 2019 were divided into high-ALP group and low-ALP group or high-LDH group and low-LDH group. Statistical analysis was carried out to study the differences between the high-ALP and low-ALP groups or the high-LDH and low-LDH groups. Furthermore, the possibility of preoperative ALP or LDH as prognostic factor of periampullary carcinoma was investigated.

RESULTS

In both the high-ALP and the high-LDH groups, the prognosis of patients with periampullary carcinoma who underwent PD was worse than that of the low-ALP and low- LDH group. Even through risk factor analysis, it was found that preoperative ALP and LDH could be independent prognostic factor for patients with periampullary carcinoma who underwent PD.

CONCLUSION

Preoperative ALP or LDH is an independent risk factor for periampullary carcinoma.

Synthetic biomarkers: a twenty-first century path to early cancer detection

Detection of cancer at an early stage when it is still localized improves patient response to medical interventions for most cancer types. The success of screening tools such as cervical cytology to reduce mortality has spurred significant interest in new methods for early detection (for example, using non-invasive blood-based or biofluid-based biomarkers). Yet biomarkers shed from early lesions are limited by fundamental biological and mass transport barriers - such as short circulation times and blood dilution - that limit early detection. To address this issue, synthetic biomarkers are being developed. These represent an emerging class of diagnostics that deploy bioengineered sensors inside the body to query early-stage tumours and amplify disease signals to levels that could potentially exceed those of shed biomarkers. These strategies leverage design principles and advances from chemistry, synthetic biology and cell engineering. In this Review, we discuss the rationale for development of biofluid-based synthetic biomarkers. We examine how these strategies harness dysregulated features of tumours to amplify detection signals, use tumour-selective activation to increase specificity and leverage natural processing of bodily fluids (for example, blood, urine and proximal fluids) for easy detection. Finally, we highlight the challenges that exist for preclinical development and clinical translation of synthetic biomarker diagnostics.

The Value of Alkaline Phosphatase-to-Albumin Ratio in Detecting Synchronous Metastases and Predicting Postoperative Relapses among Patients with Well-Differentiated Pancreatic Neuroendocrine Neoplasms

Backgrounds

Pancreatic neuroendocrine neoplasm (pNEN) is a highly heterogeneous entity, presenting widely varied biological behavior as well as long-term prognosis. Reliable biomarkers are urgently needed to make risk stratifications for pNEN patients, which could be beneficial to the development of individualized therapeutic strategy in the clinical practice. Here, we aimed to evaluate the predictive and prognostic roles of serum alkaline phosphatase-to-albumin ratio (APAR) in well-differentiated pNEN patients.

Methods

We retrospectively analyzed the pathologically confirmed grade 1/2 pNEN patients, who were originally treated in our hospital from February 2008 to April 2018. Univariate and multivariate analyses were performed to assess the value of APAR in detecting synchronous metastases and predicting relapses following curative resections.

Results

A total of 170 eligible cases were included into analysis. Logistic univariate analysis indicated APAR (P=0.002) was significantly associated with synchronous distant metastasis among well-differentiated pNEN patients, which was further demonstrated to be an independent risk factor by multivariate analysis (odds ratio 8.127, 95% confidence interval (CI) 2.105–31.372, P=0.002) was significantly associated with synchronous distant metastasis among well-differentiated pNEN patients, which was further demonstrated to be an independent risk factor by multivariate analysis (odds ratio 8.127, 95% confidence interval (CI) 2.105–31.372, P=0.002) was significantly associated with synchronous distant metastasis among well-differentiated pNEN patients, which was further demonstrated to be an independent risk factor by multivariate analysis (odds ratio 8.127, 95% confidence interval (CI) 2.105–31.372, P=0.002) was significantly associated with synchronous distant metastasis among well-differentiated pNEN patients, which was further demonstrated to be an independent risk factor by multivariate analysis (odds ratio 8.127, 95% confidence interval (CI) 2.105–31.372, P=0.002) was significantly associated with synchronous distant metastasis among well-differentiated pNEN patients, which was further demonstrated to be an independent risk factor by multivariate analysis (odds ratio 8.127, 95% confidence interval (CI) 2.105–31.372,

Conclusion

APAR may work as a convenient pretreatment marker to detect synchronous distant metastasis for well-differentiated pNEN patients and predict recurrences for curatively resected cases without nerve or vascular invasion. However, these findings should be further verified in prospectively well-designed studies.

Prognostic value of a new score using serum alkaline phosphatase and pleural effusion lactate dehydrogenase for patients with malignant pleural effusion

BACKGROUND

The objective of our study was to analyze the prognostic value of the combination of serum ALP and pleural effusion LDH (AL score) for malignant pleural effusion (MPE) patients.

METHODS

This study includes retrospective, descriptive and observational research from 1 June 2006 to 1 December 2017, which aimed to identify prognostic factors related to MPE patients. We analyzed the association of various clinical features, routinely tested markers from peripheral blood and MPE at diagnosis and overall survival (OS). All MPE patients were assigned to three groups according to their AL score. The impact of the AL score and other prognostic factors were evaluated with multivariable regression.

RESULTS

According to their AL score, 193 patients were assigned to three groups with 25 in group 0 (sALP < 65 U/L and pLDH < 155 U/L), 121 in group 1 (sALP > 65 U/L or pLDH > 155 U/L) and 47 (sALP > 65 U/L and pLDH > 155 U/L) in group 2. For groups 0, 1 and 2, median survival times (MST) were 23, 15 and 7 months, respectively. Among the three groups, MST, serum albumin level, C reactive protein, erythrocyte sedimentation rate, the ratios of platelet-to-lymphocyte, neutrophil-to-lymphocyte showed significant differences. The counts of neutrophils, monocytes, platelets and AL score (0 vs. 1, P = 0.038, hazard ratio [HR]: 1.858, 95% confidence interval [CI]: [1.034, 3.339]; 0 vs. 2, P = 0.001, HR: 2.993, 95% CI: [1.556, 5.531]) were independent prognostic indicators for OS of MPE patients.

CONCLUSION

AL score is a promising indicator which can be used to predict the prognosis of MPE patients. It can assist physicians in the selection of patients for appropriate palliative treatment.

KEY POINTS

To our knowledge, this paper is the first study that combined two enzymes (sALP and pLDH) from serum and pleural effusion and studied the prognostic value for MPE patients. It has been proved to be a promising indicator to assist physicians select patients for appropriate palliative treatment.

Prognostic value of combined preoperative lactate dehydrogenase and alkaline phosphatase levels in patients with resectable pancreatic ductal adenocarcinoma

Serum enzymes, including lactate dehydrogenase (LDH) and alkaline phosphatase (ALP), have recently been reported to play important roles in tumor growth. Increases in LDH and ALP have been confirmed to predict poor prognosis in patients with various cancers. However, their prognostic value in pancreatic cancer has not been well studied. Therefore, we reviewed the preoperative data on LDH and ALP in 185 pancreatic ductal adenocarcinoma (PDAC) patients who underwent surgery between July 2005 and December 2010 to explore the prognostic value of these markers. The cutoff points were determined based on the upper limit of their normal values. The Chi-square test was used to analyze the relationships between LDH/ALP and clinical characteristics. Univariate and multivariate analyses were performed to identify the predictive value of the above factors for disease-free survival (DFS) and overall survival (OS). We found that elevation of LDH was related to carbohydrate antigen 19-9 (CA19-9), lymph node involvement, tumor size, TNM, distant metastasis, and recurrence. Additionally, ALP was correlated to perineural invasion. After multivariate analysis, LDH and ALP were identified as independent prognostic factors for DFS and OS, and elevation of LDH/ALP was correlated with poor DFS and OS. Notably, there was a positive correlation between LDH and ALP. The predictive power of LDH combined with ALP was more sensitive than that of either one alone. Therefore, we conclude that the preoperative LDH and ALP values are prognostic factors for PADC, and the prognostic accuracy of testing can be enhanced by the combination of LDH and ALP.

Photoacoustic Tomography Detects Early Vessel Regression and Normalization During Ovarian Tumor Response to the Antiangiogenic Therapy Trebananib

The primary aim of this study was to assess the potential of in vivo photoacoustic tomography for direct functional measurement of ovarian tumor response to antiangiogenic therapy.

METHODS

In vivo studies were performed with institutional animal care and use committee approval. We used an orthotopic mouse model of ovarian cancer treated with trebananib (n = 9) or vehicle (n = 9). Tumor-bearing mice were randomized into trebananib or vehicle groups at day 10 and dosed on days 12, 15, and 18 after implantation. Photoacoustic tomography and blood draws were performed at day 10 and then 24 h after each drug dose. Tumors were excised for histopathology after the final studies on day 19. Data analysis to test for statistical significance was performed blinded.

RESULTS

Blockade of angiopoietin signaling using trebananib resulted in reduced total hemoglobin-weighted photoacoustic signal (n = 9, P = 0.01) and increased oxyhemoglobin-weighted photoacoustic signal (n = 9, P < 0.01). The latter observation indicated normalization of the residual tumor vessels, which was also implied by low levels of angiopoietin 1 in serum biomarker profiling (0.76 ± 0.12 ng/mL). These noninvasive measures reflected a 30% reduction in microvessel density and increased vessel maturation in ex vivo sections.

CONCLUSION

Photoacoustic tomography is able to evaluate both vessel regression and normalization in response to trebananib. Noninvasive imaging data were supported by modulation of serum markers in vitro and ex vivo histopathology.

Clinical characteristics and treatment options for two types of osteoblastoma in the mobile spine: a retrospective study of 32 cases and outcomes

PURPOSE

A retrospective study of 32 patients with osteoblastoma (OBL) in the mobile spine was performed to analyze the clinical characteristics of two types of spinal OBL. We also aimed to find influential factors for OBL in the mobile spine.

METHODS

Between 2002 and 2011, 32 patients with either conventional osteoblastoma (CO) or aggressive osteoblastoma (AO) in the mobile spine were treated in our center. All patients were treated with either total excision or subtotal excision + postoperative radiotherapy. The mean follow-up was 45.8 (18-128) months. Clinical data and surgery efficacy were analyzed to search for clinical characteristics of two subtypes of spinal OBL and discuss the possible factors influencing relapse.

RESULTS

There is significant difference between CO and AO in tumor size (p < 0.0005), preoperative alkaline phosphatase (ALP, p < 0.0005) and intraoperative blood loss (p = 0.013). Multivariate logistic regression was used to find the influential factors for relapse and the results were: preoperative ALP, b = 0.023, p = 0.029; surgery protocol, b = -7.597, p = 0.007; tumor size, ≥3/<3, b = 24.805, p < 0.0005; age, b = 0.054, p = 0.632; and pathology type, b = 1.998, p = 0.34.

CONCLUSIONS

Tumor size, preoperative ALP and CT images were helpful for distinguishing AO from CO. The difference in intraoperative blood loss between CO and AO is mainly attributed to the size of the lesion. Preoperative ALP, surgery protocol and tumor size (≥3/<3) were considered to significantly influence relapse of spinal OBL.

Increased pretreatment levels of serum LDH and ALP as poor prognostic factors for nasopharyngeal carcinoma

Serum enzymes that play potential roles in tumor growth have recently been reported to have prognostic relevance in a diverse array of tumors. However, prognosis-related serum enzymes are rarely reported for nasopharyngeal carcinoma (NPC). To clarify whether the level of serum enzymes is linked to the prognosis of NPC, we reviewed the pretreatment data of lactate dehydrogenase (LDH), alkaline phosphatase (ALP), and glutamyl transferase (GGT) in 533 newly diagnosed NPC patients who underwent radical radiotherapy between May 2002 and October 2003 at Sun Yat-sen University Cancer Center. Patients were grouped according to the upper limit of normal values of LDH, ALP, and GGT. The Kaplan-Meier method and log-rank test were used for selecting prognostic factors from clinical characteristics and serum enzymes, and the Chi-square test was applied to analyze the relationships of clinical characteristics and serum enzymes. Finally, a Cox proportional hazards model was used to identify the independent prognostic factors. We found that increased levels of LDH had poor effects on both overall survival and distant metastasis-free survival (P = 0.009 and 0.035, respectively), and increased pretreatment level of serum ALP had poor effects on both overall survival and local recurrence-free survival (P = 0.037 and 0.039, respectively). In multivariate analysis, increased LDH level was identified as an independent prognostic factor for overall survival. Therefore, we conclude that increased pretreatment serum LDH and ALP levels are poor prognostic factors for NPC.

Secreted blood reporters: insights and applications

Secreted reporters detected in body fluids (blood, serum or urine) have shown to be simple and useful tools for ex vivo real-time monitoring of in vivo biological processes. Here we explore the most commonly used secreted blood reporters in experimental animals: secreted alkaline phosphatase, soluble marker peptides derived from human carcinoembryonic antigen and human chorionic gonadotropin, as well as Gaussia luciferase. We also comment on other recently discovered secreted luciferases and their potential use as blood reporters for multiplexing applications.

3D tumour models: novel in vitro approaches to cancer studies

3D in vitro models have been used in cancer research as a compromise between 2-dimensional cultures of isolated cancer cells and the manufactured complexity of xenografts of human cancers in immunocompromised animal hosts. 3D models can be tailored to be biomimetic and accurately recapitulate the native in vivo scenario in which they are found. These 3D in vitro models provide an important alternative to both complex in vivo whole organism approaches, and 2D culture with its spatial limitations. Approaches to create more biomimetic 3D models of cancer include, but are not limited to, (i) providing the appropriate matrix components in a 3D configuration found in vivo, (ii) co-culturing cancer cells, endothelial cells and other associated cells in a spatially relevant manner, (iii) monitoring and controlling hypoxia- to mimic levels found in native tumours and (iv) monitoring the release of angiogenic factors by cancer cells in response to hypoxia. This article aims to overview current 3D in vitro models of cancer and review strategies employed by researchers to tackle these aspects with special reference to recent promising developments, as well as the current limitations of 2D cultures and in vivo models. 3D in vitro models provide an important alternative to both complex in vivo whole organism approaches, and 2D culture with its spatial limitations. Here we review current strategies in the field of modelling cancer, with special reference to advances in complex 3D in vitro models.

Generation of a syngeneic mouse model to study the intraperitoneal dissemination of ovarian cancer with in vivo luciferase imaging

In order to facilitate the discovery and investigation of anti-cancer therapeutics under physiological conditions, we have engineered the ovarian cancer cell line, HM-1/luc, in mice. This cell stably expresses firefly luciferase and produces light that can be detected using an in vivo imaging system (IVIS). Parental HM-1 cells cause severe carcinomatous peritonitis to B6C3F1 mice, but not to C57BL6 mice. Established HM-1/luc cells showed pathologically similar findings to HM-1 cells. HM-1/luc cells were injected into the peritoneal cavity of B6C3F1 mice and IVIS 2000 was conducted weekly after inoculation to monitor intra-peritoneal tumor growth. The mice were divided into three groups: non-CDDP-treated (control) and CDDP-treated (0.2 and 0.4 mg). A disease-suppressive effect of the CDDP was reflected by the significantly prolonged survival of the CDDP-treated mice (control 23 +/- 1.9 days, CDDP 0.2 mg 29.6 +/- 2.9 days; p < 0.05); the total photon and area of flux were decreased. The optical imaging of intraperitoneal tumors via in vivo bioluminescence is effective for noninvasive monitoring and semi-quantitative analysis. Our syngeneic mouse model has the relevant clinical features of ovarian cancer, which makes it a useful model for developing new ovarian cancer therapies.

Biomarker system for studying muscle, stem cells, and cancer in vivo

Bioluminescent reporter genes are sensitive in situ tools for following disease progression in preclinical models, albeit they are subject to scattering and absorption in deep tissues. We have generated a bicistronic Cre/LoxP reporter mouse line that pairs the expression of firefly luciferase with quantifiable expression of a human placental alkaline phosphatase that is secreted into the serum (SeAP). With the use of this dual-modality bioreporter with a novel, inducible Pax7-CreER line for tracking muscle satellite cells, we demonstrate the longitudinal kinetics of muscle stem cell turnover, accounting for a doubling of the signal from satellite cell and progeny every 3.93 wk in the transition from adolescence to early adulthood. We also show that this dual-modality bioreporter can be incorporated in preclinical cancer models, whereby SeAP activity is reflective of tumor burden. Thus, this dual bioreporter permits both spatial localization and accurate quantification of biological processes in vivo even when the tissue of interest is deep within the animal.

Multiplexing bioluminescent and fluorescent reporters to monitor live cells

Reporter proteins are valuable tools to monitor promoter activities and characterize signal transduction pathways. Many of the currently available promoter reporters have drawbacks that compromise their performance. Enzyme-based reporter systems using cytosolic luciferases are highly sensitive, but require a cell lysis step that prevents their use in long-term monitoring. By contrast, secreted bioluminescent reporters like Metridia luciferase and Secreted Alkaline Phosphatase can be assayed repeatedly, using supernatant from the same live cell population to produce many sets of data over time. This is crucial for studies with limited amounts of cells, as in the case of stem cells. The use of secreted bioluminescent reporters also enables broader applications to provide more detailed information using live cells; for example, multiplexing with fluorescent proteins. Here, data is presented describing the characteristics of secreted Metridia luciferase and its use in multiplexing applications with either Secreted Alkaline Phosphatase or a fluorescent protein.

Adeno-associated virus-mediated delivery of a mutant endostatin in combination with carboplatin treatment inhibits orthotopic growth of ovarian cancer and improves long-term survival

A human ovarian cancer cell line, which migrates to mouse ovaries and establishes peritoneal carcinomatosis, was used to evaluate the cooperative effect of an antiangiogenic gene therapy combined with chemotherapy. The ovarian carcinoma cell line MA148 was genetically modified by "Sleeping Beauty" transposon-mediated delivery of DsRed2 fluorescent protein. Stable, high-level expression of DsRed protein enabled in vivo imaging of peritoneal dissemination of ovarian cancer. Both external and internal imaging, along with histopathology, showed migration of i.p. injected human ovarian cancer cell line to mouse ovaries. Using this model, we evaluated the effect of adeno-associated virus (AAV)-mediated expression of a mutant endostatin either alone or in combination with carboplatin treatment. A single i.m. injection of recombinant AAV (rAAV)-mutant human endostatin with P125A substitution (P125A-endostatin) showed sustained expression of mutant endostatin. Antiangiogenic gene therapy inhibited orthotopic growth of ovarian cancer and resulted in 33% long-term tumor-free survival. A single cycle of carboplatin treatment combined with mutant endostatin gene therapy resulted in 60% of the animals remaining tumor free for >200 days, which was significantly better than rAAV-LacZ and/or carboplatin. Combination treatment delayed tumor appearance in 40% of the animals, wherein the residual tumors were smaller in size with limited or no peritoneal metastasis. These studies suggest that AAV-mediated gene therapy of P125A-endostatin in combination with carboplatin is a useful method to inhibit peritoneal dissemination of ovarian carcinoma.

A mathematical model to study the effects of drugs administration on tumor growth dynamics

A mathematical model for describing the cancer growth dynamics in response to anticancer agents administration in xenograft models is discussed. The model consists of a system of ordinary differential equations involving five parameters (three for describing the untreated growth and two for describing the drug action). Tumor growth in untreated animals is modelled by an exponential growth followed by a linear growth. In treated animals, tumor growth rate is decreased by an additional factor proportional to both drug concentration and proliferating cells. The mathematical analysis conducted in this paper highlights several interesting properties of this tumor growth model. It suggests also effective strategies to design in vivo experiments in animals with potential saving of time and resources. For example, the drug concentration threshold for the tumor eradication, the delay between drug administration and tumor regression, and a time index that measures the efficacy of a treatment are derived and discussed. The model has already been employed in several drug discovery projects. Its application on a data set coming from one of these projects is discussed in this paper.

Radioimmunotargeting of human rhabdomyosarcoma using monoclonal antibody 8H9

Although metastatic rhabdomyosarcoma (RMS) is chemotherapy and radiotherapy responsive, few patients are cured. 8H9, a murine IgG(1) monoclonal antibody, recognizes a unique cell surface tumor antigen broadly distributed on neuroectodermal, epithelial, and mesenchymal tumors, including RMS. We now report on the in vitro characterization of radiolabeled 8H9 and its in vivo immunotargeting potential in mice with subcutaneous human RMS. Saturation-binding studies carried out to determine (125)I-8H9 affinity to the RMS cell line HTB82 demonstrated that (125)I-8H9 had a K(d) of 10.3nM with an estimated 115,000 binding sites on every HTB82 cell. (125)I-8H9 was retained on the cell surface without significant internalization. Biodistribution of (125)I-8H9 was studied in athymic mice bearing HTB82 xenografts. Following intravenous injection of 4.44MBq of (125)I-8H9, selective tumor uptake was evident 4 to 172 hours after injection. Average tumor uptake was 7.0 +/- 1.8, 11.5 +/- 3.9, 15.1 +/- 3.7, and 5.4 +/- 1.2% injected dose per gram at 4, 24, 48, and 172 hours, respectively. Mean tumor: tissue ratios were maximal at 172 hours (for lung, 4, kidney, 6, liver, 7, spleen, 11, femur, 14, muscle, 18, and brain, 48). Established RMS xenografts treated with a single injection of 18.5 MBq (131)I-8H9 were significantly suppressed compared to controls. Radiolabeled 8H9 effectively targeted RMS xenografts and may have a potential clinical role in radioimmunotherapy.

Inhibition of phosphatidylinositol 3-kinase sensitizes ovarian cancer cells to carboplatin and allows adjunct chemotherapy treatment

Signal transduction pathways associated with cancer progression and chemotherapeutic resistance are being investigated as molecular targets for chemotherapy. The phosphatidylinositol 3-kinase (PI3K) pathway has been found to be frequently amplified and have increased activity in ovarian cancer. The current study investigates the efficacy of an antagonist of PI3K, LY294002, in inhibiting ovarian cancer cell growth and survival both in vitro and in vivo. The hypothesis tested is that inhibition of PI3K signaling makes ovarian cancer cells susceptible to the effects of platinum-based chemotherapy. Observations show that LY294002 is an effective inhibitor of ovarian cancer cell growth and survival in vitro. Inhibition of PI3K/Akt signaling increased the sensitivity of ovarian cell cultures to the cytotoxic effects of carboplatin. The combined treatment of LY294002 and carboplatin was needed to optimally promote cellular apoptosis and decrease ovarian cancer cell survival in vitro. To extend these observations, a model involving in vivo i.p. growth of human ovarian tumors in a nude mouse was used. LY294002 in combination with carboplatin was more effective in inhibiting ovarian cancer cell xenograft growth than either agent alone. The results of this study suggest that the combined treatment of carboplatin and LY294002 can effectively decrease ovarian tumor progression and support the use of a PI3K inhibitor (e.g., LY294002) as an adjunct platinum-based drug therapy for treatment of ovarian cancer.

Gene silencing in primary and metastatic tumors by small interfering RNA delivery in mice: quantitative analysis using melanoma cells expressing firefly and sea pansy luciferases

Silencing of oncogenes or other genes contributing to tumor malignancy or progression by RNA interference (RNAi) offers a promising approach to treating tumor patients. To achieve RNAi-based tumor therapy, a small interfering RNA (siRNA) or siRNA-expressing vector needs to be delivered to tumor cells, but little information about its in vivo delivery has been reported. In this study, we examined whether the expression of the target gene in tumor cells can be suppressed by the delivery of RNAi effectors to primary and metastatic tumor cells. To quantitatively evaluate the RNAi effects in tumor cells, mouse melanoma B16-BL6 cells were stably transfected with both firefly (a model target gene) and sea pansy (an internal standard gene) luciferase genes to obtain B16-BL6/dual Luc cells. The target gene expression in subcutaneous primary tumors of B16-BL6/dual Luc cells was significantly suppressed by direct injection of the RNAi effectors followed by electroporation. The expression in metastatic hepatic tumors was also significantly reduced by an intravenous injection of either RNAi effector by the hydrodynamics-based procedure. These results indicate that the both RNAi effectors have a potential to silence target gene in tumor cells in vivo when successfully delivered to tumor cells.

Models of ovarian cancer--are we there yet?

Ovarian cancer is the most lethal of all gynecological cancers and arises most commonly from the surface epithelium. Successful clinical management of patients with epithelial ovarian cancer is limited by the lack of a reliable and specific method for early detection, and the frequent recurrence of chemoresistant disease. Experimental models are of crucial importance not only to understand the biological and genetic factors that influence the phenotypic characteristics of the disease but also to utilize as a basis for developing rational intervention strategies. Ovarian cancer cell lines derived from ascites or primary ovarian tumors have been used extensively and can be very effective for studying the processes controlling growth regulation and chemosensitivity or evaluating novel therapeutics, both in vitro and in xenograft models. While our limited knowledge of the initiating events of ovarian cancer has restricted the development of models in which the early pathogenic events can be studied, recent advances in the ability to manipulate gene expression in ovarian surface epithelial cells in vitro and in vivo have begun to provide insights into the molecular changes that may contribute to the development of ovarian cancer. This review highlights the strengths and weaknesses of some of the current models of ovarian cancer, with special consideration of the recent progress in modeling ovarian cancer using genetically engineered mice.

Characterization of intraperitoneal, orthotopic, and metastatic xenograft models of human ovarian cancer

Improvement of ovarian cancer patient outcome requires well-characterized animal models in which to evaluate novel therapeutics. Xenograft models are frequently used, but with little discussion of disease histology. The objectives of this study were to inject 11 ovarian cancer cell lines intraperitoneally (ip), and a subset intrabursally (ib; orthotopic), into nude mice and to analyze the resulting pathologies. Eight of 11 lines injected ip formed tumors within 3 months at variable rates with the following histological subtype distribution: one endometrioid, one serous, one clear cell, and five undifferentiated. Only mice injected with A2780-cp cells presented with ovarian-specific metastases (11 of 88), and the survival time of these animals was significantly shorter, which may be attributed to the higher proliferation rate as determined by Ki67 positivity. Additional analysis of the influence of the ovarian microenvironment on cell characteristics was conducted with ib injection of two cell lines (OVCA 429 and ES-2). The site of injection did not affect the tumor histology, the effect on proliferation was cell-type dependent, and the tumor take rate (cell survival) was negatively affected for OVCA 429 cells. The animal models described herein represent histologically distinct models of both early and late stage ovarian cancer useful for evaluation of therapeutics.

Rodent models for ovarian cancer research

Animal models that are biologically and clinically relevant are essential for conducting research to investigate the pathophysiologic progression of disease and to develop diagnostic or therapeutic strategies. Several rodent models that vary in methods of induction allow appropriate in vivo evaluation for ovarian cancer. The types of rodent models discussed include chemically (nonhormonal and hormonal) induced, genetic (knockout and transgenic), xenograft, and syngeneic. A summary of the available rodent models is provided with a discussion of the advantages and disadvantages of each. Optimization and application of these rodent models to future research may benefit the detection and treatment of ovarian cancer.