Expression of vascular endothelial growth factor by human renal cancer cells enhances angiogenesis of primary tumors and production of ascites but not metastasis to the lungs in nude mice

Prognostic value of the ascites characteristics in pseudomyxoma peritonei originating from the appendix

Background

Pseudomyxoma peritonei (PMP) is a rare disease, with the overall survival (OS) influenced by many factors. To date, no ascites characteristics have been reported to predict OS of patients with PMP. The present study therefore aims to describe the ascites characteristics for PMP and identify prognostic factors for survival.

Methods

Between June 2010 and June 2020, 473 PMP patients who underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy were included in a retrospective study. Survival analysis was performed with the Kaplan-Meier method by the log-rank test and a Cox proportional hazards model. Associations between categorical variables were analyzed using the chi-squared test.

Results

Among all included patients, 61% were women. The median OS was 47 months (range, 4-124 months) at the last follow-up in December 2020. Ascites characteristics can be divided into light blood ascites, "Jelly" mucus ascites, and faint yellow and clear ascites. Multivariate Cox analysis showed that the degree of radical surgery, ascites characteristics, and pathological grade were independently associated with OS in PMP patients. The chi-squared test documented that faint yellow "Jelly" ascites were related to low-grade PMP and light blood ascites were associated with high-grade PMP (P < 0.01).

Conclusions

Light blood ascites, incomplete cytoreduction surgery, and high-grade histopathology may predict poor OS in appendix-derived PMP.

Thinking outside the shunt-sterile CSF malabsorption in pilocytic astrocytomas: case series and review of the literature

INTRODUCTION

Ventriculoperitoneal (VP) shunt insertion is the most common cerebrospinal fluid (CSF) diversionary procedure used for the treatment of chronic hydrocephalus. Sterile CSF ascites is a rare complication of VP shunt insertion. This can arise from either an overproduction of CSF or inadequate filtration of CSF at the level of the peritoneum. By either mechanism, the development of CSF ascites requires an intact VP shunt.

OBJECTIVE

The authors discuss two paediatric cases diagnosed with suprasellar pilocytic astrocytomas treated with platinum-based chemotherapy, who subsequently developed sterile CSF ascites. We review the literature with regard to CSF malabsorption and discuss it as a contributing factor to shunt malfunction.

CONCLUSION

CSF malabsorption with resultant ascites is a rare complication of VP shunting with many etiologies. Two common predisposing factors included the use of platinum-based chemotherapeutic agents, as well as the specific neuropathology. Further analysis of these two entities is needed in order to elucidate their role in contributing to the development of CSF ascites in this patient cohort.

Intraperitoneal administration of cisplatin plus bevacizumab for the management of malignant ascites in ovarian epithelial cancer: results of a phase III clinical trial

Bevacizumab is a humanized antihuman VEGF-A monoclonal antibody. This study aims to evaluate the efficacy and safety of intraperitoneal administration of cisplatin plus bevacizumab (Avastin) in the management of malignant ascites in ovarian epithelial cancer. Fifty-eight ovarian epithelial cancer patients with malignant ascites were randomly assigned to receive either intraperitoneal administration of cisplatin only (control group, n = 27, cisplatin: 40 mg/m(2) every 2 weeks, for 6 weeks) or cisplatin plus bevacizumab (study group, n = 31, cisplatin: 40 mg/m(2), bevacizumab: 300 mg, every 2 weeks for 6 weeks). All patients regularly received TC regimen (paclitaxel 135 mg/m(2) d1 + carboplatin AUC 5 d1) every 3 weeks. The outcome, quality of life (QoL) and adverse effect of the treatment were analyzed, and VEGF and CA-125 level in ascites were detected by ELISA. After treatment with cisplatin plus bevacizumab, VEGF level in ascites was significantly decreased compared to baseline (P < 0.05). Meanwhile, ascites VEGF level of study group was significantly lower than that of control group (P < 0.05). The overall response rate (ORR) of study group was significantly higher than that of control group (ORR 90.32 vs. 59.26 %, P < 0.05). QoL improvement rate of study group was also significantly higher than that of control group (93.55 vs. 48.15 %, P < 0.05). All patients were well tolerated, and no serious adverse effect occurred. Intraperitoneal administration of cisplatin plus bevacizumab is effective and safe for the management of malignant ascites in ovarian epithelial cancer.

Relationship between tumour angiogenesis and expression of cyclo-oxygenase-2 and vascular endothelial growth factor-A in human renal cell carcinoma

OBJECTIVE

*These authors contributed equally to this work. To study the relationship between tumour angiogenesis and expression of cyclo-oxygenase (COX)-2 and vascular endothelial growth factor (VEGF)-A in human renal cell carcinoma.

METHODS

Archival samples of primary human renal cell carcinoma tissue and surrounding normal renal tissue (control samples) obtained from patients diagnosed with renal cell carcinoma were analysed for COX-2 and VEGF-A expression by immunohistochemistry using specific monoclonal antibodies. Tumour microvasculature was examined using factor VIII-related antigen antibody staining.

RESULTS

A total of 33 renal cell carcinoma and 12 control renal tissue specimens were included. COX-2 and VEGF-A genes were overexpressed in tumour specimens compared with normal epithelia. A significant correlation was found between COX-2 and VEGF-A expression. Microvessel density was found to be increased in tumour tissues that expressed COX-2 and VEGF-A.

CONCLUSION

Microvessel density was increased in tumour tissues that expressed COX-2 and VEGF-A, suggesting that COX-2 and VEGF-A are related to tumour angiogenesis in human renal cell carcinoma.

Chemotherapy-induced cerebrospinal fluid malabsorption in a shunted child: case report and review of the literature

Ventriculoperitoneal (VP) shunt insertion is one of the most common neurosurgical procedures for the treatment of chronic hydrocephalus. Although regarded as a relatively benign procedure, several complications including obstruction, infection and mechanical failure can be seen during the postoperative stage. Symptomatic sterile cerebrospinal fluid (CSF) ascites and hydrothoracies are rare complications of VP shunt surgery. The paucity of cases makes identifying the aetiological factors difficult, particularly without catheter tip migration. It is most likely that several factors interact to reduce the absorption of CSF. The authors discuss the case of a 5-year-old girl who developed CSF ascites and a pleural effusion after starting chemotherapy for a suprasellar pilocytic astrocytoma, 2 years post-VP shunt insertion, due to a secondary obstructive hydrocephalus. After the initial management of the presenting symptoms, the child's VP shunt was subsequently changed to a ventriculo-atrial shunt and the patient made an unremarkable recovery. We also review the literature pertaining to this rare complication, assessing identifiable risk factors and surgical management options.

Intraperitoneal VEGF inhibition using bevacizumab: a potential approach for the symptomatic treatment of malignant ascites?

Despite overall improvements in oncological care in the palliative setting, symptomatic malignant ascites remains a severe clinical problem. This form of effusion is known to be widely resistant to established modes of systemic therapy. Accordingly, frequent paracentesis often represents the only effective way for symptom relief in patients with advanced cancer. This invasive mode of therapy, however, is often very burdensome for the patient who is already severely distressed by the underlying malignancy. Recently, the trifunctional monoclonal antibody catumaxomab given i.p. has shown symptom relief in patients with ovarian cancer and malignant ascites. On another front, the release of vascular endothelial growth factor (VEGF) by tumor cells has been identified as a main factor promoting the i.p. secretion of fluid. Accordingly, recent evidence suggests that targeting VEGF may have the potential to suspend the ascites production resulting from peritoneal metastasis. Here, we review preclinical and clinical data supporting this hypothesis. We show current evidence suggesting that the i.p. application of the anti-VEGF antibody bevacizumab, which is already in use as an i.v. therapeutic drug for a variety of tumors, might represent an effective way to prevent local fluid accumulation. Because such an effect would result in significant relief for patients, future clinical studies should stringently assess the effectiveness of this targeted therapy for the treatment of malignant i.p. effusions.

The tumor microenvironment and metastatic disease

The microenvironment of solid tumors is a heterogeneous, complex milieu for tumor growth and survival that includes features such as acidic pH, low nutrient levels, elevated interstitial fluid pressure (IFP) and chronic and fluctuating levels of oxygenation that relate to the abnormal vascular network that exists in tumors. The metastatic potential of tumor cells is believed to be regulated by interactions between the tumor cells and their extracellular environment (extracellular matrix (ECM)). These interactions can be modified by the accumulation of genetic changes and by the transient alterations in gene expression induced by the local tumor microenvironment. Clinical and experimental evidence suggests that altered gene expression in response to the hypoxic microenvironment is a contributing factor to increased metastatic efficiency. A number of genes that have been implicated in the metastatic process, involving angiogenesis, intra/extravasation, survival and growth, have been found to be hypoxia-responsive. The various metastatic determinants, genetic and epigenetic, somatic and inherited may serve as precedents for the future identification of more genes that are involved in metastasis. Much research has focused on genetic and molecular properties of the tumor cells themselves. In the present review we discuss the epigenetic and physiological regulation of metastasis and emphasize the need for further studies on the interactions between the pathophysiologic tumor microenvironment and the tumor extracellular matrix.

Micronodular transformation as a novel mechanism of VEGF-A-induced metastasis

How and why tumors metastasize is still a matter of debate. The assumption is that mutations render tumor cells with a metastatic phenotype, enabling entrance in and transport through lymph or blood vessels. Distant outgrowth is thought to occur only in a suitable microenvironment (the seed and soil hypothesis). However, the anatomical location of most metastases in cancer patients suggests entrapment of tumor cells in the first microcapillary bed that is encountered. We here investigated how vascular endothelial growth factor-A (VEGF-A) attributes to the metastatic process. We describe here that VEGF-A enhances spontaneous metastasis by inducing intravasation of heterogeneous tumor cell clusters, surrounded by vessel wall elements, via an invasion-independent mechanism. These tumor clusters generate metastatic tissue embolisms in pulmonary arteries. Treatment of tumor-bearing mice with the antiangiogenic compound ZD6474 prevented the development of this metastatic phenotype. This work shows that tumors with high constitutive VEGF-A expression metastasize via the formation of tumor emboli and provides an alternative rationale for anti-VEGF-A therapy, namely to inhibit metastasis formation.

PROGNOSTIC ROLE OF FUHRMAN GRADE AND VASCULAR ENDOTHELIAL GROWTH FACTOR IN pT1a CLEAR CELL CARCINOMA IN PARTIAL NEPHRECTOMY SPECIMENS

PURPOSE

Conventional renal cell carcinoma (RCC) is characterized by rich neovascularization and shows a fine vascular network around tumor cells. Nephron sparing surgery has been established as a method of choice or necessity for localized tumors. We investigated the importance of microvessel density (MVD), vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor (Flk-1) immunohistochemical expression in a large series of small conventional clear cell renal carcinomas treated with partial nephrectomy and assessed the prognostic value of their expression in terms of patients survival at long-term followup.

MATERIALS AND METHODS

A total of 48 patients with a mean age +/- SD of 58.2 +/- 9.5 years who had conventional single RCC were considered. Median tumor diameter was 2.92 +/- 0.82 cm (range 1.3 to 5). Disease was grades 1 to 4 in 15, 29, 2 and 2 patients, respectively. Median followup was 92.9 months (range 17 to 186).

RESULTS

Four patients (3.9%) had died of metastatic renal cancer at a median followup of 23.5 months, of whom 1 had a grade 2, 1 had a grade 3 and 2 had grade 4 RCC. Patients with MVD expression higher than the median (44.4 vessels per mm) did not show a significant difference in survival compared to patients with MVD expression lower than the median. Patients with VEGF expression higher than 25% in the histological specimen showed worse survival than patients with VEGF expression lower than 25%. Different Flk-1 expression did not determine a significant difference in survival. On univariate analysis of patient survival in relation to the different considered factors Fuhrman grading was the most important factor for survival.

CONCLUSIONS

Our study shows that recurrence and death are possible even in patients with small renal tumors. MVD, VEGF and Flk-1 expression do not depend on tumor size in pT1a RCC. Therefore, to date Fuhrman grading appears to be the only factor predictive of survival even in small RCC. Thus, Fuhrman grading is predictive of mortality. While VEGF is not predictive of survival as a single parameter, based on its percent of expression (lower or higher than 25%) it can determine 2 groups that are different from the prognostic point of view.

Vascular endothelial growth factor expression promotes the growth of breast cancer brain metastases in nude mice

Patients with breast cancer brain metastases cannot be cured and have a poor prognosis, with a median survival time of six months after diagnosis, despite developments in diagnostic and therapeutic modalities. In large part the progress in understanding the biology of breast cancer brain metastasis has been limited by the lack of suitable cell lines and experimental models. The objective of this study was to develop a reliable experimental model to study the pathogenesis of breast cancer brain metastases, using intra-internal carotid artery injection of breast cancer cells into nude mice. Brain metastasis-selected variant cells were recovered after three cycles of injection into the internal carotid artery of nude mice and harvest of brain metastases, resulting in variants termed MDA-231 BR1, -BR2 and -BR3. The metastasis-selected cells had increased potential for experimental brain metastasis and mice injected with these cells had significantly shorter mean survival than mice injected with the original cell line. Brain metastatic lesions of the selected variants contained significantly more CD31-positive blood vessels than metastases of the non-selected cell line. The variants selected from brain metastases released significantly more VEGF-A and IL-8 into culture supernatants than the original cell line, and more VEGF-A RNA when cultured in normoxic conditions. Mice injected with MDA-231 BR3 into the carotid artery were treated with the VEGF-receptor tyrosine kinase inhibitor PTK787/Z 222584. Oral administration of the inhibitor resulted in a significant decrease in brain tumor burden, reduced CD31-positive vessels in the brain lesions and incidence of PCNA positive tumor cells, and increased apoptosis in the tumor, as measured by TUNEL labeling. We conclude that elevated VEGF expression contributes to the ability of breast cancer cells to form brain metastases. Targeting endothelial cells with a VEGF-receptor specific tyrosine kinase inhibitor reduced angiogenesis and restricted the growth of the brain metastases.

Expanding the Clinical Development of Bevacizumab

Bevacizumab (Avastin; Genentech, Inc.; South San Francisco, CA) is a recombinant, humanized monoclonal antibody to vascular endothelial growth factor, a key regulator of tumor angiogenesis. Bevacizumab demonstrated potent antitumor activity in preclinical models and has also shown biologic activity and clinical benefit in clinical studies. Notably, a randomized, placebo-controlled phase II trial in renal cell carcinoma demonstrated a significantly longer time to tumor progression with bevacizumab monotherapy. Furthermore, in a phase III trial for untreated advanced colorectal cancer, the addition of bevacizumab to chemotherapy led to significantly longer overall survival and progression-free survival times than chemotherapy alone. The clinical development of bevacizumab has been expanded to include confirmatory phase III trials and exploratory phase II trials in a variety of solid tumors and hematologic malignancies. Treatment regimens being examined include bevacizumab alone and in combination with conventional chemotherapy, radiation, immune therapy, and biologically targeted agents.

Recruitment of marrow-derived endothelial cells to experimental choroidal neovascularization by local expression of vascular endothelial growth factor

PURPOSE

The question of whether adult animals maintain a reservoir of endothelial progenitor cells (EPCs) in the bone marrow that is involved in neovascularization is under investigation. The following study was undertaken to examine the potential contribution of EPCs to the development of choroidal neovascularization (CNV) in adult mice and to examine the role of local expression of vascular endothelial growth factor (VEGF) in this process.

METHODS

Lethally irradiated, adult female nude mice were engrafted with whole bone marrow isolated from male transgenic mice expressing LacZ driven by the endothelial specific Tie-2 promoter. Two months, following bone marrow reconstitution, confirmed by quantitative Taqman PCR, an E1-deleted adenoviral vector expressing vascular endothelial growth factor (165) (Ad.VEGF(165)) was injected subretinally to induce CNV, confirmed by collagen IV immunohistochemistry. Bone marrow-derived endothelial cells were detected using either X-gal staining or Y chromosome in situ hybridization. Y chromosome positive cells within the CNV were confirmed to be endothelial cells by lectin staining.

RESULTS

Subretinal Ad.VEGF(165) was capable of inducing CNV. Four-week old lesions were found to contain LacZ expressing cells within the CNV in bone marrow transplanted animals but not in negative control animals. Eighteen percent of all Y chromosome positive cells within the CNV were found to be lectin positive while 27% of all endothelial cells within the CNV were Y chromosome positive.

CONCLUSION

Engrafted bone marrow-derived EPCs were shown to differentiate into endothelial cells at the site of subretinal VEGF-induced CNV in mice. These results suggest that EPCs contribute to the formation of neovascularization and that subretinal expression of VEGF might play an important role in recruitment of these cells to the site of CNV.

Selection of more aggressive variants of the gI101A human breast cancer cell line: a model for analyzing the metastatic phenotype of breast cancer

In vivo models utilizing orthotopic injection of tumor cells into nude mice have proven valuable for the study of metastasis. However, breast cancers are among the more difficult of human tumors to grow in immunodeficient mice, with a relatively low tumor take. Fewer still develop spontaneous metastases. The injection of GI101A breast cancer cells into the mammary fatpad (mfp) produced lung metastases in 25% of tumor-bearing mice. Selecting cells from the lung metastases and recycling in vivo resulted in the isolation of a series of variant cell lines. These cell lines were tested for tumorigenicity and metastasis in nude mice following mfp injection compared with the original cell line, and in vitro expression of factors associated with the metastatic phenotype measured. The in vivo selected cell lines were more aggressive, with higher tumor take, faster local growth rate and increased incidence (> or = 85%) and extent of lung metastasis. However, the metastasis-selected variants showed no increases in expression of the growth factor receptors EGFR or HER-2, and the pro-angiogenic factors VEGF-A and IL-8. Immunohistochemistry of mfp tumors revealed no differences in microvessel density (counting CD-31 positive structures) and cell proliferation (PCNA-positive cells) comparing the GI101A line with selected variants. No TUNEL-positive cells were detected in the tumors of the metastasis-derived variant, with a small number of cells undergoing apoptosis detected in sections of GI101A tumors. In vitro, the metastasis-derived variants were found to have a more robust expression of phosphorylated PKB/Akt, with or without EGF or serum stimulation, suggesting an association between Akt activation and metastatic ability. This new series of isogenic cell lines may be valuable for identifying molecular mechanisms involved in the metastatic progression of breast cancer.

Renal cell carcinoma: new prognostic factors?

PURPOSE OF REVIEW

There are limited independent predictors of survival in patients with renal cell carcinoma. Factors related to the tumor, host and treatment may help us to predict prognosis to a certain extent. Prognostic indicators would enable selection of patients who can benefit from adjuvant therapy and thus should be enrolled in clinical trials. This review highlights developments in the identification of current prognosticators for patients with renal cell carcinoma.

RECENT FINDINGS

Tumor stage, grade and patient-performance status are the known prognostic indicators in renal cell carcinoma. Besides these parameters, many molecular and cytogenetic markers were evaluated recently. Unfortunately, none of these parameters appear to be a better predictive prognostic factor than the usual staging and grading. Therefore, efforts to identify new markers for tumor proliferation and progression are still ongoing. It was recently reported that low carbonic anhydrase 9 staining may be an independent poor prognostic factor in patients with renal cell carcinoma. Moreover, there is increasing interest in prognostic indices and predictive algorithms for survival. Staging systems that combine the pathological features with additional prognostic variables have been constructed to predict outcome. The UCLA Integrated Staging System seems to be superior to staging alone in differentiating patients' survival.

SUMMARY

Although the literature reviewed contains numerous promising clinical, histological, molecular and cytogenetic parameters, none of them has yet been shown to have an independent prognostic value

Thrombospondin-1, vascular endothelial growth factor expression and microvessel density in renal cell carcinoma and their relationship with multifocality

OBJECTIVE

To evaluate the relevance of microvessel density (MVD) and the angiogenic factors, vascular endothelial growth factor (VEGF, an important angiogenic factor in solid tumors) and thrombospondin-1 (TSP-1, a potent inhibitor of angiogenesis), to multifocality of renal cell carcinoma (RCC).

PATIENTS AND METHODS

Using immunohistochemistry the expression of CD34, TSP-1 and VEGF was assessed in 38 archival tissue specimens from 19 patients with unifocal RCC and 19 with multifocal RCC. Immunostaining results for VEGF was scored for the appropriate percentage of positive tumor cells and relative immunostaining intensity (score range 0-12). Only extracellular immunoreactivity was considered positive for TSP-1 and the same method was used to score the stromal staining. The microvessel density was measured by immunohistochemical staining with anti-CD34 monoclonal antibody.

RESULTS

VEGF immunoreactivity> or =1% was detectable in all unifocal and multifocal tumors. TSP-1 immunoreactivity was detected in 14 (73.7%) of 19 unifocal RCCs and in 16 (84.2%) of 19 multifocal RCC specimens (p=0.69). There were no statistically significant differences in the immunostaining intensity, percentage of immunopositive cells and the staining scores of VEGF and TSP-1 among the two groups. Additionally, there was no difference in MVD in multifocal and unifocal tumors.

CONCLUSION

As there is no difference in MVD count, and expression of angiogenic factors (VEGF and TSP-1) in multifocal and unifocal tumors, multifocality of RCC is not determined by VEGF/TSP-1 expression.

Clinical significance of urinary vascular endothelial growth factor and microvessel density in patients with renal cell carcinoma

OBJECTIVES

To investigate the urinary vascular endothelial growth factor (VEGF) levels from patients with renal cell carcinoma (RCC). Neovascularization, an essential event for the growth of solid tumors, is regulated by a number of angiogenic factors. VEGF is thought to exert potent angiogenic activity.

METHODS

Urine samples were obtained before radical nephrectomy from 27 patients with RCC and 10 control subjects with no evidence of cancer or inflammatory disease. VEGF was measured by enzyme-linked immunosorbent assay in the urine and corrected according to the 24-hour urine concentration of creatinine. The microvessel density was measured by immunohistochemical staining with CD31 monoclonal antibody. Nuclear morphometry was performed by photomicroscopy.

RESULTS

The corrected urinary VEGF levels in patients with RCC were much higher than those in the normal control group (P = 0.039) and were more elevated in patients with higher stages of RCC (Stages III and IV versus Stages I and II; P = 0.024). A tendency was also noted for the VEGF levels to be higher according to cell grade. However, no statistical correlation was found between the corrected urinary VEGF and age, sex, tumor size, cell type, microvessel density, platelet count, or hemoglobin. The nuclear area was higher with more advanced-stage tumors (P = 0.043) and tended to increase according to the tumor cell grade.

CONCLUSIONS

The results of this study indicate that urinary VEGF levels are increased in patients with RCC. However, they may not reflect the underlying angiogenic activity, and it may be that other angiogenic factors play a more prominent role.