Bevacizumab as a potential anti-angiogenic therapy in schistosomiasis: A double-edged, but adjustable weapon

AIM

Investigating the anti-angiogenic effect of bevacizumab on chronic schistosomiasis mansoni in a trial to hinder the Schistosome-induced angiogenesis and porto-systemic shunting complications.

METHODS

The immunohistochemical expression of CD34, VEGF-R1, PCNA and α-SMA (angiogenesis markers) was analysed in the lung, liver and gastrointestinal junctions of chronic S mansoni infected mice after intraperitoneal injection of bevacizumab. The effect of prolonged administration of bevacizumab with praziquantel was also assessed through parasitic load, protective index, granuloma and fibrous tissue evaluation.

RESULTS

A regression in the vascular activity and microvascular density was observed in the infected mice after receiving bevacizumab. They had a significantly less VEGF-R1, PCNA, CD-34 and α-SMA expression in comparison to the infected untreated mice. The least tissue egg count was reported in mice received bevacizumab for 6 weeks (Mean = 27 120). However, they had persistent liver granulomas, and massively amalgamated fibrosis. Interestingly, the least faecal egg and tissue worms counts (Mean = 112, 13.4), and the highest protection index (39.26) were reported in mice received bevacizumab for 3 weeks, with marked granuloma, and fibrous tissue resolution.

CONCLUSIONS

Bevacizumab has a promising protective effect against the Schistosoma-induced angiogenesis. As an adjuvant to praziquantel, it is important to adjust the appropriate duration of administration that achieves the best schistosomicidal effect without impeding granuloma and fibrous tissue resolution.

Angiogenesis in Schistosoma haematobium-associated urinary bladder cancer

Schistosoma haematobium, a parasitic flatworm that infects more than 100 million people, mostly in the developing world, is the causative agent of urogenital schistosomiasis, and is associated with a high incidence of squamous cell carcinoma (SCC) of the bladder. During infection, eggs are deposited in the bladder causing an intense inflammatory reaction. Angiogenesis is defined as the formation of new blood vessels from preexisting ones and is recognized as a key event in cell proliferation and carcinogenesis and spread of malignant lesions. A growing amount of evidence points to angiogenesis playing a key role in schistosomiasis-associated bladder cancer. Thus, identifying biomarkers of this process plays an important role in the study of cancer. Here, we review recent findings on the role of angiogenesis in bladder cancer and the growth factors that induce and assist in their development, particularly SCC of the bladder associated to urogenital schistosomiasis.

Biomarkers in bladder cancer: translational and clinical implications

Bladder cancer is associated with high recurrence and mortality rates. These tumors show vast heterogeneity reflected by diverse morphologic manifestations and various molecular alterations associated with these disease phenotypes. Biomarkers that prospectively evaluate disease aggressiveness, progression risk, probability of recurrence and overall prognosis would improve patient care. Integration of molecular markers with conventional pathologic staging of bladder cancers may refine clinical decision making for the selection of adjuvant and salvage therapy. In the past decade, numerous bladder cancer biomarkers have been identified, including various tumor suppressor genes, oncogenes, growth factors, growth factor receptors, hormone receptors, proliferation and apoptosis markers, cell adhesion molecules, stromal factors, and oncoproteins. Recognition of two distinct pathways for urothelial carcinogenesis represents a major advance in the understanding and management of this disease. Nomograms for combining results from multiple biomarkers have been proposed to increase the accuracy of clinical predictions. The scope of this review is to summarize the major biomarker findings that may have translational and clinical implications.

Angiogenesis and parasitic helminth-associated neovascularization

Successful metazoan parasitism, among many other factors, requires a supply of nutrients and the removal of waste products. There is a prerequisite for a parasite-defined vasculature. The angiogenic mechanism(s) involved presumably depend on the characteristics of the tissue- and vascular system-dwelling, parasitic helminths. Simplistically, 2 possibilities or a combination of both have been considered in this review. The multifactorial induction of parasitic helminth-associated neovascularization could arise through, either a host-, a parasite- or a host-/parasite-dependent, angiogenic switch. Most studies appear to support the first and third hypotheses, but evidence exists for the intrahepatic cestodeEchinococcus multilocularis, the free-living nematodeCaenorhabditis elegansand the intravascular trematodeSchistosoma mansonifor the second inference. In contrast, the nematode anti-coagulant protein NAPc2 from adultAncylostoma caninumis also an anti-angiogenic factor.

Adjuvant and neoadjuvant radiotherapy for bladder cancer: revisited

To date, radical cystectomy has continued to be the treatment of choice for muscle-invasive bladder cancer. It is associated with a 5-year disease-free survival rate ranging from 27–55%. This outcome is significantly worse when reporting upon locally advanced cases. The independent prognostic factors include: tumor stage, grade, pelvic nodal involvement and some other additional factors. Beside the higher reported incidence of distant metastasis, local recurrence either alone or combined with systemic relapse has been shown to be experienced by 23–50% of locally advanced patients – a rate that was much more frequent than previously believed. Nonrandomized trials of preoperative radiotherapy have suggested improved survival rates. However, only one out of the six randomized preoperative trials in the literature published in English has proved to be significant. On the other hand, the only randomized trial and most retrospective studies dealing with postoperative radiotherapy revealed a significant increase in disease-free survival. Late complications of post operative radiotherapy, contrary to former belief, were acceptable and generally depended upon the volume of the irradiated normal tissues and the radiotherapy techniques used. Most of these adjuvant or neoadjuvant reports were performed in the 1970s and 1980s using conventional radiation techniques. Modern radiotherapy, delivering higher doses to the tumor while saving a significant amount of the surrounding normal structure, has not been rigorously tested. However, these techniques have already succeeded in improving treatment end results in other pelvic tumors.

Evaluation of colon cancer vascularity by flash echo imaging

OBJECTIVE

Tumor vascularity is strongly related to the prognoses of patients with various malignant primary tumors, including colorectal cancer. The aim of this study was to confirm the usefulness of harmonic flash echo imaging (H-FEI) for the preoperative evaluation of tumor vascularity in colorectal cancer by comparison with CD34 staining of resected specimens.

MATERIAL AND METHODS

Seventeen patients undergoing surgical resection for advanced colorectal cancer (9 M, 8 F) were enrolled in this study. An ultrasound system transmitting ultrasound pulses at 2.3 MHz and receiving them at 4.6 MHz (second harmonic) was used for H-FEI. After intravenous injection of ultrasonic contrast medium (SHU 508A), intermittent harmonic scanning was carried out for 120 s at intervals of 4 s. On the tumor image of the strongest enhancement in each patient, 5 regions of interest were taken to decide the mean echo intensity of the tumor. Immunohistochemistry using antibodies against CD34 was carried out on resected specimens. The mean microvessel density was decided by counting microvessels on 5 fields (x 400) of CD34-stained specimens.

RESULTS

The mean value of H-FEI intensity was 5.44+/-1.10, and the mean microvessel count with CD34 staining was 35.0+/-7.95. A significant positive linear correlation was observed between the intensity of H-FEI determined preoperatively and the microvessel count in CD34-stained specimens (r=0.741, p=0.0006).

CONCLUSION

Vascularity of colon cancer can be evaluated non-invasively using H-FEI.

Proliferating cell nuclear antigen (PCNA) overexpression and microvessel density predict survival in the urinary bladder carcinoma

OBJECTIVE

To study proliferating cell nuclear antigen (PCNA) over expression and angiogenesis with their relationship to tumor parameters in squamous cell carcinoma of the urinary bladder in patients who underwent radical cystectomy.

PATIENTS AND METHODS

The mean age of the patients was 53.53 years (range; 29-70 years) and the males were 98 of 154. Sections from paraffin embedded tissues were retrieved and stained with antibodies against PCNA for proliferation and CD34 for angiogenesis using immunohistochemical technique. Fisher's exact test was used to evaluate the relationship between categorical variables and the Kaplan-Meier procedure was used to assess survival outcomes. The Cox regression model was used for multivariate analysis.

RESULTS

The median follow up period was 65 months. microvessel density (MVD), PCNA, tumor grade, P-stage, DNA ploidy, lymph node status had a significant impact on the 5-year survival of patients in univariate analysis. In Cox proportional hazard model, MVD, PCNA, DNA ploidy and stage sustained their significant impact on survival of the patients.

CONCLUSIONS

MVD, PCNA, DNA ploidy and stage are independent prognostic factors in patients with squamous cell carcinoma of the urinary bladder.

Long-term results of primary adenocarcinoma of the urinary bladder: A report on 192 patients

OBJECTIVES

To evaluate the clinical presentation and treatment end results of primary adenocarcinoma of the urinary bladder, and to determine the significant independent prognostic factors that determine this outcome.

PATIENTS AND METHODS

Of 3659 patients who underwent cystectomy, 192 had adenocarcinoma of the urinary bladder, with a relative frequency of 5.2%. Most of these patients (68.2%) presented in late stages (P3 + P4). The incidence of pelvic lymph nodes involvement was 25.5%. Mucinous adenocarcinoma was reported in 28 patients (14.6%), papillary in 20 (10.4%), signet ring in 14 (7.3%), while not otherwise specified was reported in 130 (67.7%) in the cystectomy specimens.

RESULTS

Mucinous and signet-ring histologic subtypes showed increased frequency of high stages and high grades, and more nodal involvement than the papillary and not otherwise specified. All patients were treated with radical cystectomy and pelvic lymphadenectomy with (69 patients) or without (123) postoperative radiotherapy. The 5-year disease-free survival rate was 46 +/- 4% for all patients with adenocarcinoma. Postoperative radiotherapy improved the disease-free survival significantly. The 5-year disease-free survival rate for the postoperative radiotherapy group was 61 +/- 6% compared to 37 +/- 5% for the cystectomy alone group (P = 0.002). Local control rate was significantly improved from 53 +/- 7% for cystectomy alone to 96 +/- 3% for postoperative radiotherapy patients (P = 0.00001). Distant metastases were the leading cause of death in the postoperative radiotherapy group.

CONCLUSIONS

Within the limitations provided by retrospective studies, it could be concluded that postoperative radiotherapy improved the disease-free survival through its effect on local control. The disease-free survival independent prognostic variables were tumor stage, postoperative radiotherapy, nodal involvement, and adenocarcinoma subclassification. These factors, except the adeno-subclassification, were also found to determine the local control rate. On the other hand, the independent prognostic factors for distant metastasis were lymph nodal involvement, stage, and adeno-subclassification.

Inhibition of tumor angiogenesis during cisplatin chemotherapy for bladder cancer improves treatment outcome

OBJECTIVES

To investigate the effect of inhibiting tumor angiogenesis during cisplatinum-(II)-diamine dichloride (cisplatin) chemotherapy of bladder cancer (BC) in a rat model.

METHODS

Bladder cancer was induced in 64 male rats using 0.05% N-butyl-N-(4-hydroxybutyl)-nitrosamine in their water supply for 20 weeks. The animals were then divided randomly into four groups of 16 rats each: a control BC group (group 1); a BC group treated with cisplatin (0.25 mg/kg body weight) by intraperitoneal injection twice every week (group 2); a BC group treated with the antiangiogenic factor TNP-470 (30 mg/kg body weight) by intraperitoneal injection twice every week (group 3); and a BC group treated with cisplatin plus TNP-470 (group 4, treatment regimens as described). Per group, 4 rats were killed weekly after the start of treatment, for 4 weeks. BC was confirmed using histologic characteristics, and the treatment outcomes were determined by measuring tumor microvascular density and cell proliferation and apoptosis indexes (PI and AI, respectively).

RESULTS

All animals had confirmed BC. Both group 3 (TNP-470) and group 4 (cisplatin plus TNP-470) had significantly decreased microvascular density compared with group 1 (P <0.05). Although both the PI and AI were significantly different between group 4 (cisplatin plus TNP-470) and group 1 (control BC; P <0.05), neither the PI nor AI was significantly different between group 2 (cisplatin) and group 4 (cisplatin plus TNP-470; P >0.05).

CONCLUSIONS

TNP-470 in conjunction with cisplatin chemotherapy resulted in a decrease in the microvascular density of BC in a rat model. However, TNP-470 did not appear to have a significant impact on the cisplatin effect against BC as measured by apoptosis and cell proliferation.

Relation between serum anti-p53 antibodies and microvessel density in bladder cancer patients

INTRODUCTION

Etiology of serum anti-p53 antibodies in bladder cancer patients is still unknown. In this study we evaluated the relationship between serum anti-p53 antibodies and microvessel density in bladder cancer patients.

MATERIALS AND METHODS

Seventy-six patients with transitional cell carcinoma of the urinary bladder were assessed prospectively (18 Ta, 30 T1, 28 T2>or =). Serum anti-p53 antibodies were detected by enzyme-linked immunosorbent assay. Tumor p53 overexpression was assessed by immunohistochemical staining. Vessels were stained immunohistochemically using an antibody against platelet endothelial cell-adhesion molecule CD31. Spearman correlation test and t test were used for statistical analysis.

RESULTS

Serum anti-p53 antibodies were positive in 25 (60%) of 41 tumor p53-positive patients. While the mean (SD, range) microvessel density was found to be 43 (7.59, 8-99) in patients who had positive serum anti-p53 antibodies, it was found to be 23 (4.53, 6-98) in patients who had negative serum anti-p53 antibodies. There was a good correlation between serum anti-p53 antibodies and microvessel density (p<0.05). No correlation was found between tumor p53 expression and microvessel density (p>0.05).

CONCLUSIONS

We found that there is a significant correlation between the microvessel density and serum anti-p53 antibodies. This result may show the role of angiogenesis in the etiology of serum anti-p53 antibodies in bladder cancer patients.

Prognostic value of angiogenesis in schistosoma-associated squamous cell carcinoma of the urinary bladder

OBJECTIVES

To evaluate angiogenesis as a prognostic marker in squamous cell carcinoma of the urinary bladder in 154 patients who underwent radical cystectomy.

METHODS

The tumors from 98 men and 56 women (mean age 46.3 +/- 8.4 years) were examined. Vessels were stained using an antibody to the platelet endothelial cell adhesion molecule CD31. Microvessels were counted in active areas of angiogenesis within the tumors. Microvessel density (MVD) was quantified using the mean of three counts. Age, sex, tumor grade and stage, DNA ploidy, and MVD were evaluated in relation to outcome. Univariate and multivariate analyses of survival were performed.

RESULTS

The median follow-up period was 63 months. The overall 5-year survival rate was 56 +/- 4.1. Tumor grade, tumor stage, DNA ploidy, and MVD had a significant impact on the survival of patients in univariate analysis. The 5-year survival rate in patients with a low MVD (11 or less) was 68.1% compared with 50.4% for those with a high MVD (greater than 11; P <0.01). Men had more vascular tumors than did women. Also, high-grade tumors had significantly higher vascular counts. In a Cox proportional hazard model, tumor angiogenesis sustained its significant impact on survival of the patients in addition to tumor stage and DNA ploidy.

CONCLUSIONS

These findings suggest that angiogenesis and DNA ploidy are independent additional prognostic factors in patients with squamous cell carcinoma of the urinary bladder.