This Month in Investigative Urology

Article Outline

• Cytogenetic Aberrations in Infertile Men
• Enhanced Oncolytic Activity of VSV Encoding the SV5-F Protein Against Prostate Cancer
• HAMLET Treatment Delays Bladder Cancer Development
• AP214 Protects Against Ischemia Induced Acute Kidney Injury
• Copyright

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Cytogenetic Aberrations in Infertile Men 

Infertility is a major health problem of multifactorial etiology that involves males and females, and affects nearly 6 million couples in the United States. The causes of male infertility are heterogeneous but more than 50% of cases have a genetic basis. Since specific genetic defects have been identified in less than 20% of infertile males, the majority of causes remain to be elucidated. The most common cytogenetic defects associated with nonobstructive azoospermia are numerical and structural chromosome abnormalities, including Klinefelter syndrome (47,XXY) and Y chromosome microdeletions. Yatsenko et al (page 1636) from Houston, Texas reviewed the cytogenetic results in 668 infertile men with oligozoospermia and azoospermia referred for routine cytogenetic analysis between January 2004 and March 2009. High resolution Giemsa banding chromosome analysis and/or fluorescence in situ hybridization was performed.

The overall incidence of chromosomal abnormalities was approximately 8.2%. Of the 55 patients with abnormal cytogenetic findings sex chromosome aneuploidies were observed in 29, including 27 with Klinefelter syndrome. Structural chromosome abnormalities involving autosomes (29%) and sex chromosomes (18%) were detected in 26 infertile men. Abnormal cytogenetic findings were observed in 13.3% (35 of 264) of patients with azoospermia and 5.2% (19 of 365) with oligozoospermia. The authors conclude that structural chromosomal defects and low level sex chromosome mosaicism are frequent in oligozoospermia, and suggest that extensive cytogenetic evaluation and fluorescence in situ hybridization analysis may improve the detection rate in oligozoospermic males. They also emphasize that these findings highlight the need for efficient genetic testing of infertile men so that couples can make informed decisions concerning the use of assisted reproductive technologies to achieve parenthood.

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Enhanced Oncolytic Activity of VSV Encoding the SV5-F Protein Against Prostate Cancer 

There is a pressing need to develop new therapeutic approaches for advanced prostate cancer. Oncolytic viruses offer a promising strategy to target tumor cells since they may show a natural preference for tumor cells or preferential replication in malignant cells due to defects in host defense and cell cycle control pathways. Vesicular stomatitis virus (VSV) has been investigated as an oncolytic agent and has shown promise in treating experimental models of various cancers, including breast and prostate cancer. However, VSV can induce a strong immune response that results in the generation of neutralizing antibodies, and can enter and replicate in the central nervous system, potentially limiting its clinical usefulness.

Chang et al (page 1611) from Pittsburgh, Pennsylvania and Memphis, Tennessee report on the construction of a recombinant, replication restricted VSV encoding the simian virus 5 fusion protein (SV5-F) that is capable of inducing syncytia formation with enhanced oncolytic properties against TRAMP-C2 tumors in an immunocompetent mouse model of prostate cancer. The SV5-F recombinant replication restricted VSV vector was constructed by replacement of the VSV G gene with that of the SV5-F transgene to generate rVSV-ΔG-SV5-F. Morphological changes and DNA fragmentation induced by rVSV-ΔG-green fluorescent protein (GFP) or rVSV-ΔG-SV5-F were determined by phase contrast microscope and gel electrophoresis. In vitro cytotoxicity by rVSVs was performed by MTT assay and in vivo study of rVSVs treatment was done in immunocompetent mice by subcutaneous administration of TRAMP-C2 cells.

In vitro characterization of the recombinant fusogenic VSV-ΔG vector on TRAMP-C2 cells showed significantly enhanced apoptotic and cytotoxic effects relative to rVSV-ΔG-GFP. Intratumor administration of rVSV-ΔG-SV5-F in mice with subcutaneous TRAMP-C2 tumors resulted in a significant reduction of tumor load compared to the nonfusogenic GFP control virus and heat inactivated rVSV in the treated animals regardless of initial tumor size (p <0.01). The authors conclude that G complemented recombinant VSV-ΔG vectors, especially rVSV-ΔGSV5-F, are an effective oncolytic agent against mouse prostate cancer cells in vitro and in an in vivo immunocompetent mouse model. Expression of SV5-F may increase the oncolytic potency of VSV by directly enhancing apoptosis and eliciting an antitumor response. The combination of increased oncolytic potency and limited replication ability paves the way for the development of VSV as a therapeutic strategy for prostate cancer.

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HAMLET Treatment Delays Bladder Cancer Development 

Transitional cell carcinomas are common urological malignancies. Tumors confined to the mucosa are treated topically by intravesical instillation of bacillus Calmette-Guerin or with surgery followed by cytostatic drugs. Bacillus Calmette-Guerin treatment may result in prolonged tumor-free periods and delayed tumor progression but it is also associated with severe side effects, especially in immunocompromised individuals. Therefore, there is a need for less toxic drugs with more tumor specific properties.

Human α-lactalbumin made lethal to tumor cells (HAMLET) is a protein-lipid complex that kills different types of cancer cells. Mossberg et al (page 1590) evaluated the therapeutic effect of HAMLET in the mouse MB49 bladder carcinoma model where tumors were established by intravesical injection of MB49 cells into poly-L-lysine treated bladders of C57BL/6 mice. The treatment groups received repeat intravesical instillations of HAMLET, while controls received α-lactalbumin or phosphate buffer. The effects of HAMLET on tumor size and putative apoptotic effects were analyzed in bladder tissue sections. Whole body imaging was used to study HAMLET distribution in tumor bearing mice compared to healthy bladder tissue.

HAMLET caused a dose dependent decrease in MB49 cell viability in vitro. Five intravesical HAMLET instillations significantly decreased tumor size and delayed development in vivo compared to the control group. TUNEL staining revealed selective apoptotic effects in tumor areas but not in adjacent healthy bladder tissue. On in vivo imaging Alexa-HAMLET was retained for more than 24 hours in the bladders of tumor bearing mice but not in those of tumor-free mice or tumor bearing mice receiving Alexa-α-lactalbumin. The authors conclude that HAMLET is active as a tumoricidal agent and that topical HAMLET administration may delay bladder cancer development. HAMLET may also be a useful tool to better understand conserved death pathways in tumor cells.

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AP214 Protects Against Ischemia Induced Acute Kidney Injury 

In nephron sparing surgery, eg partial nephrectomy, the renal artery and vein must be clamped. Ischemia reperfusion injury induces a complex cascade of events that results in induced acute kidney injury (AKI). The duration of clamping is typically 20 to 40 minutes with 30 minutes accepted as a safety limit. A promising agent is α-melanocyte stimulating hormone, which has been shown to protect kidneys against ischemic and sepsis induced AKI in rodents.

In a randomized, placebo controlled study in 26 pigs Simmons et al (page 1625) studied the efficacy of the α-melanocyte stimulating hormone analog AP214 against AKI. Left nephrectomy was performed laparoscopically and complete warm ischemia in the right kidney was induced for 120 minutes. AP214 was administered intravenously daily on the day of surgery and for 5 days thereafter, and kidney function was measured for 9 days. Changes in serum creatinine, estimated glomerular filtration rate (eGFR), serum C-reactive protein, and urine interleukin-18 were measured.

Mean peak serum creatinine was 10.2 and 3.92 mg/dl in the placebo and AP214 groups, respectively (p <0.001). eGFR nadir was 22.9 and 62.6 ml per minute per kg in the control and AP214 groups, respectively (p = 0.001). Functional nadir occurred at 72 and 24 hours in the control and AP214 groups, respectively. eGFR on postoperative day 9 was 118 ml per minute per kg in controls vs 156 ml per minute per kg in the AP214 group (p = 0.04). The authors conclude that the robust renoprotective effect of AP214 could be anticipated also in humans. However, studies to elucidate the mechanism(s) of action are needed as well as a phase II human clinical study in kidney transplant and partial nephrectomy populations.