PTPN3 Inhibits the Growth and Metastasis of Clear Cell Renal Cell Carcinoma via Inhibition of PI3K/AKT Signaling

The underlying molecular mechanism driving clear cell renal cell carcinoma (ccRCC) progression is still to be explored. The significant downregulation of protein tyrosine phosphatase nonreceptor type 3 (PTPN3) expression in the tumor tissues suggested its protective role in ccRCC progression. IHC analysis of PTPN3 protein in 172 ccRCC tissue revealed that PTPN3 was an independently favorable prognostic factor for progression-free survival (P = 0.0166) and overall survival (P = 0.0343) of patients. The ccRCC cell lines SN12C, 1932, ACHN, and Caki-1 were used to evaluate, both in vitro and in vivo, the biological roles of PTPN3. We observed that overexpression of PTPN3 significantly inhibited the proliferation, migration, and invasion of ccRCC cells. In contrast, the knocking down of PTPN3 elicited opposite effects. Overexpressing PTPN3 inhibited xenograft tumor growth and lung metastasis displayed by the in vivo mice models. PTPN3 inhibited tumor cell motility by suppressing the phosphorylation of AKT, and subsequently inactivating the PI3K/AKT signaling pathway of renal cell carcinoma cells. Furthermore, the inhibition of phospho-AKT^Thr308 and phospho-AKT^Ser473 reversed PTPN3-induced silencing in tumor cell migration. Our work revealed that the overexpression of PTPN3 could suppress kidney cancer progression by negatively regulating the AKT signaling pathway, and served as a favorable prognostic factor in patients with ccRCC. Our findings provided insight that PTPN3 could be a potential target for therapy aiming to inhibit the malignant behaviors of ccRCC. IMPLICATIONS: PTPN3 is an independent favorable prognostic factor for patients with ccRCC and could be a potential target for therapy aiming to inhibit the malignant behaviors of ccRCC.

Racial Disparities and Preventive Measures to Renal Cell Carcinoma

Kidney cancer ranks among the top 10 cancers in the United States. Although it affects both male and female populations, it is more common in males. The prevalence rate of renal cell carcinoma (RCC), which represents about 85% of kidney cancers, has been increasing gradually in many developed countries. Family history has been considered as one of the most relevant risk factors for kidney cancer, although most forms of an inherited predisposition for RCC only account for less than four percent. Lifestyle and other factors such as occupational exposure, high blood pressure, poor diet, and heavy cigarette smoking are highly associated with its incidence and mortality rates. In the United States, White populations have the lowest prevalence of RCC compared to other ethnic groups, while Black Americans suffer disproportionally from the adverse effects of RCC. Hence, this review article aims at identifying the major risk factors associated with RCC and highlighting the new therapeutic approaches for its control/prevention. To achieve this specific aim, articles in peer-reviewed journals with a primary focus on risk factors related to kidney cancer and on strategies to reduce RCC were identified. The review was systematically conducted by searching the databases of MEDLINE, PUBMED Central, and Google Scholar libraries for original articles. From the search, we found that the incidence and mortality rates of RCC are strongly associated with four main risk factors, including family history (genetics), lifestyle (poor diet, cigarette smoking, excess alcohol drinking), environment (community where people live), and occupation (place where people work). In addition, unequal access to improvement in RCC cancer treatment, limited access to screening and diagnosis, and limited access to kidney transplant significantly contribute to the difference observed in survival rate between African Americans and Caucasians. There is also scientific evidence suggesting that some physicians contribute to racial disparities when performing kidney transplant among minority populations. New therapeutic measures should be taken to prevent or reduce RCC, especially among African Americans, the most vulnerable population group.

Impact of Acquisition Method and Region of Interest Placement on Inter-observer Agreement and Measurement of Tumor Response to Targeted Therapy Using Dynamic Contrast-Enhanced Ultrasound

This study evaluated the impact of different acquisition methods, user-directed region of interest placement and post-processing steps on the quantification of dynamic contrast-enhanced ultrasound measurements of blood volume in 29 patients with renal cancer, pre- and post-treatment. Specifically, we compared tumor quantification using multiple planes versus a single plane, breathhold versus free breathing and large region of interest versus a region targeting the area of highest vascularity. Performance was evaluated using area under the receiver operating characteristic curves to identify the method that best predicts progression-free survival. The intra-class correlation coefficient was also used to investigate how the same parameters affect inter-observer agreement. Of the different methods used to quantify blood volume in this study, the combination that had the highest level of inter-observer agreement (intra-class correlation coefficient = 0.8-0.97) and was the best predictor of progression-free survival was the change in blood volume measured (area under receiver operating characteristic curve = 0.77, p = 0.04) by a multiplane average, acquired during quiet breathing, quantified using a region of interest that encompassed the entire tumor.

[PREVENTION OF THE BONES METASTASES OCCURRENCE IN THE PATIENTS WITH RENAL-CELL CANCER]

Diagnostic significance of estimation of the tartratresistent acid phosphatase (bone TRAP--5b) activity was studied for prognosis of occurrence of metastases in bones (MB) in patients with a renal-cell cancer (RCC). The risk of the MB occurrence was determined in patients after surgical treatment. A skeleton affection rate in patients, to whom zolendronic acid was prescribed, was trustworthy bigger, than such while conduction of treatment. So, application of bisphosphonates is recommended, in particular--zolendronic acid in dosage 4 mg every month under control of the bone TRAP--5b activity with objective of prophylaxis of the MB occurrence in patients, suffering RCC. But, we recommend for the MB diagnosis the method of determination of this marker activity as additional one while examining patients together with standard methods, including osteoscintigraphy, computer tomography.

Long-term Use of Statins and Risk of Renal Cell Carcinoma: A Population-based Case-Control Study

BACKGROUND

Use of statins has been suggested to protect against renal cell carcinoma (RCC); however, studies have typically been underpowered, and the results are conflicting.

OBJECTIVE

To determine whether the use of statins is associated with a reduced risk of RCC using high-quality registry data.

DESIGN, SETTING, AND PARTICIPANTS

We conducted a nationwide case-control study based on all histologically verified cases of RCC in Denmark between 2002 and 2012 (n=4606) matched 1:10 to cancer-free controls. Data on drug use, comorbidity, and educational level were obtained from Danish nationwide prescription, patient, and demographic registries.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Odds ratios (ORs) and 95% confidence intervals (CIs) for RCC associated with long-term use (≥5 yr) of statins were estimated using conditional logistic regression, adjusting for potential confounders.

RESULTS AND LIMITATIONS

The adjusted OR for RCC associated with long-term use of statins was 1.06 (95% CI, 0.91-1.23). Analyses stratified by duration of statin use, type of statin, and patient characteristics all yielded ORs close to unity, except for a slightly increased OR for RCC associated with long-term statin use among women (OR: 1.25; 95% CI, 0.96-1.62). The main limitation of our study was lack of information on lifestyle factors, notably obesity, which may have biased the risk estimates upward.

CONCLUSIONS

Our study does not support an important chemopreventive effect of long-term statin use against RCC. The marginally increased and statistically insignificant risk estimates can readily be interpreted as a null finding, considering the lack of control for obesity and other lifestyle risk factors.

PATIENT SUMMARY

Previous studies have shown that the use of cholesterol-lowering drugs (statins) may protect against renal cancer. In a large study including all Danish renal cancers during an 11-yr period, we found no evidence of such an effect.

Lycopene in the prevention of renal cell cancer in the TSC2 mutant Eker rat model

Renal cell carcinoma (RCC) is the most frequent upper urinary tract cancer in humans and accounts for 80-85% of malignant renal tumors. Eker rat represents a unique animal model to study RCC since these rats develop spontaneous renal tumors and leiomyoma, which may be due to tuberous sclerosis 2 (TSC2) mutation resulting in the activation of the mammalian target of rapamycin (mTOR) pathway. This study examines the role of a lycopene-rich diet in the development of RCC in the TSC2 mutant Eker rat model. Ten-week old female Eker rats (n=90) were assigned in equal numbers to receive 0, 100 or 200mg/kg of lycopene as part of their daily diet. After 18 months the rats were sacrificed and the kidneys were removed. Immunohistochemical staining with antibodies against mTOR, phospho-S6 and EGFR were performed, as well as hematoxylin-eosin staining for histologic examination of the tumors. Tumors were counted and measured in individual kidneys. Presence of tumor decreased from 94% in control animals to 65% in the experimental group, but the difference was not statistically significant (P<0.12). However, mean numbers of renal carcinomas were statistically significantly decreased in the lycopene-treated rats (P<0.008) when compared to untreated controls. In the lycopene group, tumor numbers decreased (P<0.002) and the numbers tended to decrease linearly (P<0.003) as supplemental lycopene increased from 0 to 200. Control rats fed only basal diet had a greater length of tumors (23.98 mm) than rats fed lycopene supplement groups (12.90 mm and 11.07 mm) (P<0.05). Moreover tumor length decreased (P<0.02) and tumor length tended to decrease linearly (P<0.03) as supplemental lycopene increased from 0 to 200mg/kg. All tumors showed strong staining with antibodies against mTOR, phospho-S6 and EGFR. In conclusion, dietary supplementation with lycopene attenuates the development of renal cell cancers in the predisposed TSC2 mutant Eker rat model. These results suggest that lycopene may play a role in the prevention of RCC.

Effect of habitual exercise on renal carcinogenesis by ferric nitrilotriacetate

OBJECTIVES

We investigated whether habitual exercise (HE) (treadmill running) suppresses development of renal cell carcinoma (RCC) induced by ferric nitrilotriacetate (Fe-NTA).

METHODS

Male Fischer 344 rats were divided into six groups: group I, saline treatment (12 weeks = initiation period) and non-HE; group II, Fe-NTA treatment (12 weeks) and non-HE; group III, saline treatment and short-term (12 weeks) HE; group IV, Fe-NTA treatment and short-term HE; group V, saline treatment and long-term (40 weeks) HE; and group VI, Fe-NTA treatment and long-term HE. Saline treatment groups did not develop RCC, therefore we investigated the effects of HE among Fe-NTA treatment groups.

RESULTS

Gross nodules (diagnosed as RCC), RCC represented by microcarcinomas (Mcs), karyomegalic cells (KCs), and degenerative tubules (DTs) were seen in rats treated with Fe-NTA. The number of Mcs, KCs, and DTs were increased in the short-term HE group when compared with those in the non-HE group, but were decreased in the long-term HE group when compared with those in the short-term HE group.

CONCLUSIONS

Short-term (initiation period) HE promoted renal carcinogenesis induced by Fe-NTA; however, long-term HE after the initiation period suppressed the promoted carcinogenesis.

Circulating 25-hydroxyvitamin D and risk of kidney cancer: Cohort Consortium Vitamin D Pooling Project of Rarer Cancers

Although the kidney is a major organ for vitamin D metabolism, activity, and calcium-related homeostasis, little is known about whether this nutrient plays a role in the development or the inhibition of kidney cancer. To address this gap in knowledge, the authors examined the association between circulating 25-hydroxyvitamin D (25(OH)D) and kidney cancer within a large, nested case-control study developed as part of the Cohort Consortium Vitamin D Pooling Project of Rarer Cancers. Concentrations of 25(OH)D were measured from 775 kidney cancer cases and 775 age-, sex-, race-, and season-matched controls from 8 prospective cohort studies. Overall, neither low nor high concentrations of circulating 25(OH)D were significantly associated with kidney cancer risk. Although the data showed a statistically significant decreased risk for females (odds ratio = 0.31, 95% confidence interval: 0.12, 0.85) with 25(OH)D concentrations of ≥75 nmol/L, the linear trend was not statistically significant and the number of cases in this category was small (n = 14). The findings from this consortium-based study do not support the hypothesis that vitamin D is inversely associated with the risk of kidney cancer overall or with renal cell carcinoma specifically.

Fish, vitamin D, and flavonoids in relation to renal cell cancer among smokers

Fish, vitamin D, flavonoids, and flavonoid-containing foods may have cardiovascular benefits and therefore may also reduce the risk of renal cell cancer. Risk was prospectively assessed in the Alpha-Tocopherol Beta-Carotene Cancer Prevention Study (1985-2002) cohort (N = 27,111; 15.2 mean person-years of follow-up). At enrollment, demographic, health, and dietary history information was recorded. Individuals who smoked less than 5 cigarettes/day, with chronic renal insufficiency or prior cancer, were excluded. Hazard ratios and 95% confidence intervals from Cox regression were used to compare upper quartiles (quartiles 2-4) with the lowest quartile (quartile 1) of dietary intake. Among 228 cases, risk (quartile 4 vs. quartile 1) was associated with consumption of the flavonoid quercetin (hazard ratio = 0.6, 95% confidence interval: 0.4, 0.9; P(trend) = 0.015) and Baltic herring (hazard ratio = 2.0, 95% confidence interval: 1.4, 3.0; P(trend) < 0.001), with adjustment for age, body mass index, smoking, blood pressure, alcohol use, physical activity, urban residence, and education. In geographically stratified models, the risks associated with herring and total fish intake appeared to be highest in the urban coast region, although the interaction was not statistically significant. These results suggest that the flavonoid quercetin may prevent renal cell cancer among male smokers. The possible risk associated with fish intake warrants further investigation before conclusions may be drawn.

Renal tumor natural history: the rationale and role for active surveillance

Renal cell carcinoma (RCC) is the most common malignancy of the kidney. Despite widespread treatment at diagnosis, overall mortality rates associated with RCC have not decreased. Partly because of the more frequent use of abdominal imaging, diagnosis as an incidental finding has increased. The largest increase in incidence is in tumors smaller than 4 cm, termed small renal masses (SRMs). SRMs that are RCC may frequently be growth slowly and have a low risk of early progression. Initial active surveillance with delayed treatment for progression for selected patients should be considered. This should result in an overall decrease in treatment burden and cost saving.

Physical activity during adulthood and adolescence in relation to renal cell cancer

Evidence for a relation between physical activity and renal cell cancer has been inconsistent. The authors examined physical activity in relation to renal cell cancer in a large, prospective US cohort study of 482,386 participants (289,503 men and 192,883 women) aged 50-71 years at baseline (1995-1996). At baseline, participants reported their frequency of exercise of at least 20 minutes' duration, intensity of daily routine activity, and frequency of physical activity during adolescence. During 8.2 years of follow-up (through December 2003), 1,238 cases of renal cell cancer were ascertained. In multivariate Cox regression models adjusted for renal cell cancer risk factors, the authors observed that current exercise, routine physical activity, and activity during adolescence were associated with a reduced risk of renal cell cancer. The multivariate relative risks for the highest activity level as compared with the lowest were 0.77 (95% confidence interval (CI): 0.64, 0.92; p(trend) = 0.10) for current exercise, 0.84 (95% CI: 0.57, 1.22; p(trend) = 0.03) for routine physical activity, and 0.82 (95% CI: 0.68, 1.00; p(trend) = 0.05) for activity during adolescence. The authors conclude that increased physical activity, including activity during adolescence, is associated with reduced risk of renal cell cancer.

Statins might reduce risk of renal cell carcinoma in humans: case-control study of 500,000 veterans

OBJECTIVES

Statins are commonly used cholesterol-lowering agents noted to suppress tumor cell growth in several in vitro and animal models.

METHODS

We studied the association between renal cell carcinoma and statins in veterans. A retrospective nested case-control study was conducted using prospectively collected data from the Veterans Integrated Service Networks 16 Veteran Affairs database from 1998 to 2004. We analyzed the data from 483,733 patients from eight states located in the south-central United States. The primary variables of interest were renal cell carcinoma and the use of statins before the diagnosis of renal cell carcinoma. Multiple logistic regression analysis was done to adjust for covariates, including age, sex, body mass index, and smoking. Statistical Analysis Systems software was used for statistical computing.

RESULTS

Of the 483,733 patients in the study, 164,441 (34%) were taking statins before the diagnosis of renal cell carcinoma and 1446 (0.3%) had a primary diagnosis of renal cell carcinoma. Statin use was significantly associated with a risk reduction of renal cell carcinoma of 48% (adjusted odds ratio 0.52, 95% confidence interval 0.45 to 0.60). Furthermore, the protective effect of statins was seen across different age and sex groups and was irrespective of the presence of obesity and smoking.

CONCLUSIONS

Statins appear to be protective against the development of renal cell carcinoma, after controlling for age, sex, smoking, and obesity.

The burden of illness associated with renal cell carcinoma in the United States

BACKGROUND

There were over 36,000 new cases of kidney cancer reported in the United States in 2004, the most common type being renal cell carcinoma (RCC). Available treatments for localized RCC frequently lead to cure; however RCC patients with advanced disease have limited treatment options and low survival rates. Data on the economic burden of RCC are limited.

METHODS

A prevalence-based model was used to estimate the aggregate annual societal cost burden of RCC in the U.S., including costs of treatment and lost productivity. Key parameters in the model include: the annual number of patients treated for RCC by age group and cancer stage; utilization of cancer treatments; unit costs; work-days missed; and wage rates. Multiplying stratum-specific distributions of treatment by annual quantities of treatments and unit costs yields estimates of RCC-related health-care costs. Multiplying stratum-specific estimates of annual workdays missed by average wage rates yields estimates of RCC-related lost productivity.

RESULTS

The annual prevalence of RCC in the U.S. was estimated to be 109,500 cases. The associated annual burden (inflated to 2005 U.S.$) was approximately $4.4 billion ($40,176 per patient). Health-care costs and lost productivity accounted for 92.4% ($4.1 billion) and 7.6% ($334 million), respectively. Reflecting its higher prevalence, the total cost associated with localized RCC accounted for the greatest share (78.2%), followed by regional, distant, and unstaged RCC, at 18.3%, 2.8%, and 0.7%, respectively.

CONCLUSIONS

The economic burden of RCC in the U.S. is substantial. Interventions to reduce the prevalence of RCC have the potential to yield considerable economic benefits.

Carotenoid and vitamin intake, von Hippel-Lindau gene mutations and sporadic renal cell carcinoma

OBJECTIVE

We investigated whether dietary carotenoid and vitamin intake and supplemental vitamin use were inversely associated with RCC risk and with Von Hippel-Lindau (VHL)-gene mutations in clear-cell renal cell carcinoma (RCC).

METHODS

The Netherlands Cohort Study on diet and cancer (NLCS) includes 120,852 persons, who completed a self-administered food-frequency questionnaire in 1986. After 11.3 years of follow-up, 284 cases and a random sample of 4,095 persons (subcohort) with complete data were included in multivariable analyses using a case-cohort approach. VHL gene mutational analysis was complete for 225 cases. Rate ratios and corresponding 95% confidence intervals were estimated using Cox proportional hazard models, while adjusting for age, sex, smoking, body mass index, and a history of hypertension.

RESULTS

We observed no association for dietary carotenoid and vitamin intake and RCC risk, and a somewhat increased risk with supplemental vitamin E, AD, and multivitamin use. Results were suggestive of higher RRs for alpha-carotene, beta-cryptoxanthin, folate, and supplemental vitamin C and multivitamin intake for wildtype VHL tumors compared to VHL-mutated tumors.

CONCLUSIONS

There was no association of carotenoid, vitamin or supplemental vitamin intake and RCC risk. These associations should be investigated by others to confirm the current observations.

IFN-gamma and Fas ligand are required for graft-versus-tumor activity against renal cell carcinoma in the absence of lethal graft-versus-host disease

To determine the mechanisms of graft-versus-tumor (GVT) activity in the absence of graft-versus-host disease (GVHD) against a solid tumor, we established two allogeneic bone marrow transplantation models with a murine renal cell carcinoma (RENCA). The addition of 0.3 x 10(6) donor CD8(+) T cells to the allograft increased the survival of tumor-bearing mice without causing GVHD. The analysis of CD8(+) T cells deficient in cytotoxic molecules demonstrated that anti-RENCA activity is dependent on IFN-gamma and Fas ligand (FasL), but does not require soluble or membrane-bound TNF-alpha, perforin, or TRAIL. Recipients of IFN-gamma(-/-) CD8(+) T cells are unable to reject RENCA compared with recipients of wild-type CD8(+) T cells and, importantly, neither group develops severe GVHD. IFN-gamma(-/-) CD8(+) T cells derived from transplanted mice are less able to kill RENCA cells in vitro, while pretreatment of RENCA cells with IFN-gamma enhances class I and FasL expression and rescues the lytic capacity of IFN-gamma(-/-) CD8(+) T cells. These results demonstrate that the addition of low numbers of selected donor CD8(+) T cells to the allograft can mediate GVT activity without lethal GVHD against murine renal cell carcinoma, and this GVT activity is dependent on IFN-gamma and FasL.

Secreted frizzled-related protein 1 loss contributes to tumor phenotype of clear cell renal cell carcinoma

PURPOSE

Incidence and mortality rates for renal cell carcinoma (RCC) have been rising for decades. Unfortunately, the molecular events that support RCC carcinogenesis remain poorly understood. In an effort to gain a better understanding of signaling events in clear cell RCC (cRCC), we investigated the antitumor activity of secreted frizzled-related protein 1 (sFRP1), a negative regulator of Wnt signaling.

EXPERIMENTAL DESIGN

Genomic profiling of cRCC tumors and patient-matched normal tissues was done and confirmed using quantitative PCR and immunohistochemistry. Methylation-specific PCR was done on patient samples to evaluate the mechanism responsible for sFRP1 loss. sFRP1 expression was restored in cRCC cells and the effects on tumor phenotype were characterized.

RESULTS

Genomic profiling, quantitative PCR, and immunohistochemistry indicated that loss of sFRP1 occurred in cRCC and papillary RCC patient tissues. Twelve Wnt-regulated genes were up-regulated in cRCC tissues, including c-myc and cyclin D1, potentiators of cell proliferation and survival. Methylation of the sFRP1 gene was one mechanism identified for attenuation of sFRP1 mRNA. Stable reexpression of sFRP1 in cRCC cells resulted in decreased expression of Wnt target genes, decreased growth in cell culture, inhibition of anchorage-independent growth, and decreased tumor growth in athymic nude mice.

CONCLUSIONS

To our knowledge, this is the first report to show that stable restoration of sFRP1 expression in cRCC cells attenuates the cRCC tumor phenotype. Our data support a role for sFRP1 as a tumor suppressor in cRCC and that perhaps loss of sFRP1 is an early, aberrant molecular event in renal cell carcinogenesis.

Flavonoids and the risk of renal cell carcinoma

Intake of flavonoids has been inversely related to the risk of various common neoplasms, but limited data exist on renal cell carcinoma (RCC). We used data from a case-control study conducted between 1994 and 2002 in four Italian areas to study the relation between major flavonoid classes and RCC. The study included 767 cases with incident, histologically confirmed RCC and 1,534 hospital controls admitted for acute, nonneoplastic conditions and matched with cases by study center, sex, and quinquennia of age. We applied published data on food and beverage content of six major classes of flavonoids to dietary information collected through a validated food frequency questionnaire. After adjustment for major recognized confounding factors and total energy intake, the odds ratios for subjects in the highest versus the lowest quintile of intake were 0.80 [95% confidence interval (95% CI), 0.58-1.11] for total flavonoids, 0.76 (95% CI, 0.56-1.03) for isoflavones, 0.94 (95% CI, 0.60-1.47) for anthocyanidins, 0.77 (95% CI, 0.56-1.06) for flavan-3-ols, 0.90 (95% CI, 0.67-1.21) for flavanones, 0.68 (95% CI, 0.50-0.93) for flavones, and 0.69 (95% CI, 0.50-0.95) for flavonols. Allowance for vegetable and fruit consumption only partly explained these inverse relations. Thus, flavonoids, and particularly flavones and flavonols, may account, at least in part, for the favorable role of plant foods on RCC.

Lexatumumab (TRAIL-receptor 2 mAb) induces expression of DR5 and promotes apoptosis in primary and metastatic renal cell carcinoma in a mouse orthotopic model

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in a variety of tumorigenic and transformed cell lines but not in many normal cells. Hence, TRAIL-agonist compounds have the potential of being excellent cancer therapeutic agents with minimal cytotoxicity. Here, we examine the efficacy of the TRAIL-receptor 2 agonist, lexatumumab (Human Genome Sciences, Inc., Rockville, MD), and identify molecular pathways that differentiate between lexatumumab-sensitive and lexatumumab-resistance renal cancer cells. In an orthotopic metastatic mouse model, we first demonstrate that lexatumumab was effective in reducing the tumor burden of primary and metastatic lexatumumab-sensitive xenografts. We demonstrate that lexatumumab-sensitive cells were capable of triggering both the extrinsic and the intrinsic apoptotic pathways as demonstrated by caspase 8 and caspase 9 activations, respectively, after treatment with lexatumumab. In addition, expression of c-FLIP(L) protein, an important regulator of TRAIL-induced apoptosis, decreased, while expression of the TRAIL-receptor 2, DR5, increased. This study serves as a pre-clinical model for using TRAIL-like therapies for patients with advanced RCC.

[Secondary prevention after urological tumor diseases. Focusing on the kidneys, testes, and bladder]

It is generally agreed upon that patients require a caring as well as careful medical follow-up after cancer treatment. The goal of secondary prevention is to recognize a recurrence at an early stage and to use the curative chance while the tumor mass is still small. There is evidence of a medically effective and successful follow-up for tumors of the testicle and the bladder. For quality reasons, these follow-up regimes should be adhered to for quality reasons. In other diseases, e.g., renal cell carcinoma, prospective randomized studies are missing which demonstrate the effectiveness of follow-ups. In these cases asymptomatic patients should be stratified to individualized follow-up care.

The role of surveillance in the management of small renal masses

Incidentally detected, small renal masses (SRMs) have been increasing significantly in recent years due to the widespread use of improved cross-sectional imaging. A significant number of incidental SRMs are diagnosed in elderly patients who are more likely to undergo imaging for other medical issues. The natural history of SRMs has not been historically well understood because most masses are surgically removed soon after diagnosis. Several reports of surveillance of SRMs have been published in the last few years. When followed conservatively with serial imaging, SRMs have variable growth rates with an average of 0.28 cm/year, according to a recent meta-analysis. Larger series with longer follow-up are needed, but a significant number of small tumors seem to have an indolent behavior with a slow growth rate and a limited tendency to progress. The standard of care for enhancing SRMs is surgery. Up to one-third of surgically removed, <4-cm tumors are histologically benign. The outcomes of current surgical treatment of histologically confirmed, <4-cm, renal cell carcinomas are excellent, but this has not led to a decrease in mortality. Based on these considerations and on the available data on the natural history of SRMs, it seems reasonable to consider that we may be overtreating these lesions. This is especially true for elderly or unfit patients who have a decreased life expectancy. In these selected patients and in patients who refuse active treatment, it seems reasonable to propose an initial period of active surveillance for incidental SRMs, with delayed intervention for those tumors that will exhibit fast growth during follow-up. Percutaneous needle biopsies of renal tumors can be safely performed with the use of modern techniques and have the potential to characterize SRMs at histologically diagnosis, thereby allowing a better selection of the conservative or active treatment that is best suited for each individual patient.

Lifetime physical activity and the risk of renal cell cancer

The relation between lifelong physical activity at work and during leisure-time and the risk of renal cell cancer (RCC) was analyzed in a case-control study conducted in Italy between 1992 and 2004. Cases were 767 subjects with incident, histologically confirmed RCC, and controls were 1,534 patients hospitalized for acute nonneoplastic conditions. Odds ratios (OR) and 95% confidence intervals (CI) for RCC were computed by multiple logistic regression models, conditioned on study center, sex and age, and adjusted for main covariates. Compared to the lowest level of occupational physical activity, the multivariate OR of RCC for the highest level were 0.65 (95% CI 0.49-0.87) at age 12 years, 0.67 (95% CI 0.53-0.84) at age 15-19, 0.74 (95% CI 0.59-0.93) at age 30-39 and 0.71 (95% CI 0.55-0.92) at age 50-59 years, with significant inverse trends in risk. The inverse association was consistent in strata of sex, age at diagnosis, body mass index, smoking habit and alcohol drinking. No significant association was found for leisure-time physical activity. The inverse association between occupational physical activity and RCC risk, if real, may be related to the effects of insulin-like growth factors, or lipid peroxidation and about 9% of cases of RCC in Italy could be avoided by increasing physical activity. However the inverse association might involve confounding by indirect mechanisms, such as body composition or other social class correlates.

IFN-gamma mediates CD4+ T-cell loss and impairs secondary antitumor responses after successful initial immunotherapy

Protective cell-mediated immune responses in cancer are critically dependent on T-helper type 1 (T(H)1) cytokines such as interferon-gamma (IFN-gamma). We have previously shown that the combination of CD40 stimulation and interleukin-2 (IL-2) leads to synergistic antitumor responses in several models of advanced metastatic disease. We now report that after this treatment and other immunotherapy regimens, the CD4+ T-cell population, in contrast to CD8+ T cells, did not significantly increase but rather exhibited a substantial level of apoptosis that was dependent on IFN-gamma. Mice immunized with tumor cells and treated with an immunotherapy regimen that was initially protective were later unable to mount effective memory responses compared with immunized mice not receiving immunotherapy. Immunotherapy given to tumor-bearing Ifngr-/- mice resulted in restoration of secondary responses. Thus, although immunotherapeutic regimens inducing strong IFN-gamma responses can lead to successful early antitumor efficacy, they may also impair the development of durable antitumor responses.

Monoclonal antibody to tumor necrosis factor-related apoptosis-inducing ligand receptor 2 (TRAIL-R2) induces apoptosis in primary renal cell carcinoma cells in vitro and inhibits tumor growth in vivo

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) triggers apoptosis in a variety of tumor cells through two of its receptors: TRAIL-R1 and TRAIL-R2. We investigate the susceptibility of human renal cell carcinoma (RCC) cells to TRM-1 and HGS-ETR2, 2 human monoclonal agonistic antibodies specific for TRAIL-R1 and TRAIL-R2, respectively. HGS-ETR2 effectively induced apoptotic cell death in 10 of 11 cell cultures, including 2 human RCC cell lines and 9 human primary RCC cell cultures, with a more pronounced effect after preincubation with anti-human IgG Fc. In contrast, TRM-1 was effective in only 1 primary RCC cell culture. The increased effectiveness of HGS-ETR2 for inducing cell death might have been affected by differences in the cell-surface expression of the 2 TRAIL receptors, namely that TRAIL-R2 but not TRAIL-R1 was frequently expressed in most of the RCC cells tested. The activities of caspase-9, -8, -6, and -3 were increased with HGS-ETR2-induced apoptosis, and cell death could be blocked by specific caspase inhibitors for caspase-9, -8, and -3, and the general caspase inhibitor. In vivo administration of HGS-ETR2 with or without cross-linker significantly suppressed tumor growth of subcutaneously inoculated human RCC xenografts in immunodeficient mice. These results suggest the potential utility of TRAIL-R2 antibody as a novel therapeutic agent in RCC.

Dendritic cell vaccine strategies for renal cell carcinoma

Dendritic cell (DC) vaccines are an important experimental immunotherapy for renal cell carcinomas. DC vaccines have proven safe, but only minimal clinical efficacy has been observed to date. DC vaccine strategies reflect the continually evolving understanding of DC biology. The use of mature DCs is particularly important to avoid the induction of regulatory T cells. Better defined sources of immunizing antigens and more efficient antigen-loading will contribute to DC vaccines of better quality. Improved clinical efficacy may also be achieved using DCs that secrete biologically active IL-12, which fosters innate immunity and polarizes T helper type 1 responses that contribute to optimal antitumor immunity. Furthermore, combination therapies that treat systemic immune suppression will be crucial for obtaining improved clinical responses to DC vaccines in patients with advanced disease.

Fibre intake and renal cell carcinoma: A case-control study from Italy

Only 2 previous studies, conducted in Australia, United States and northern Europe, considered the role of dietary fibre intake on renal cell carcinoma (RCC) risk, and both showed a modest, inverse association. Therefore, we investigated in depth the topic of fibres and RCC, using data from a multicenter case-control study conducted in Italy from 1992 to 2004, including 767 cases with incident, histologically confirmed RCC and 1,534 controls admitted to the same network of hospitals as cases with acute nonmalignant conditions. Multivariate odds ratios (OR) and 95% confidence intervals (CI) were obtained after allowance for major identified confounding factors, including total energy intake. The continuous OR for an increase in intake equal to the difference between the 80th and the 20th percentile were 0.94 (95% CI: 0.82-1.08) for total dietary fibre, 0.98 (95% CI: 0.85-1.13) for soluble noncellulose polysaccharides, 0.92 (95% CI: 0.80-1.05) for total insoluble fibre, 0.90 (95% CI: 0.78-1.04) for cellulose, 0.95 (95% CI: 0.84-1.06) for insoluble noncellulose polysaccharides and 1.06 (95% CI: 0.93-1.21) for lignin. With reference to the sources of fibre, we found an inverse association with vegetable fibre (OR = 0.84, 95% CI: 0.73-0.97), but no association with fruit (OR = 0.98, 95% CI: 0.86-1.12) and grain fibre (OR = 1.05, 95% CI: 0.95-1.15). The inverse association with vegetable fibre may reflect a real favorable effect, or be an indicator of a beneficial role of a diet rich in vegetable on RCC risk.

Long-lasting remission of pulmonary metastases of renal cell cancer under IFN-beta therapy in a patient with multiple sclerosis

BACKGROUND

Immunomodulary therapy based on interferon (IFN)-a has been shown to be effective in a subset of patients with advanced renal cell carcinoma (RCC). IFN-Beta has occasionally been reported to induce remissions in RCC, but is well established in the treatment of multiple sclerosis (MS). There is an ongoing debate whether hyperactivation of the immune system may convey protection against the development of cancer in MS patients.

PATIENTS AND METHODS

A 54-year-old female MS patient underwent tumor nephrectomy for RCC in 1994. 1 year later, several bilateral pulmonary metastases were documented by computed tomography and were histologically confirmed thereafter. Therapy with IFN-Beta was started.

RESULTS

Soon after initiation of IFN-Beta treatment, the patient achieved an almost complete remission which is still ongoing after 10 years of IFN-Beta therapy.

CONCLUSION

To our knowledge, this is the longest remission under IFN-Beta treatment ever reported in an RCC patient. We conclude that IFN-Beta should be particularly considered as a therapeutic option in the rare occasion of metastatic RCC in patients with MS.

Multiple Acquired Renal Carcinoma Tumor Capabilities Abolished upon Silencing of ADAM17

Malignancy is a manifestation of acquired defects in regulatory circuits that direct normal cell proliferation and homeostasis. Most of these circuits operate through cell autonomous pathways, whereas others potentially involve the neighboring microenvironment. We report that the metalloprotease ADAM17 plays a pivotal role in several acquired tumor cell capabilities by mediating the availability of soluble transforming growth factor-α, an epidermal growth factor receptor (EGFR) ligand, and thus the establishment of a key autocrine signaling pathway. Silencing of ADAM17 in human renal carcinoma cell lines corrects critical features associated with cancer cells, including growth autonomy, tumor inflammation, and tissue invasion. Highly malignant renal carcinoma cancer cells fail to form in vivo tumors in the absence of ADAM17, confirming the essential function of this molecule in tumorigenesis. These data show that ligand shedding is a crucial step in endogenous EGFR activation and endorse prospective therapeutic strategies targeting ADAM17 in human cancer. (Cancer Res 2006; 66(16): 8083-90)

Stimulation through CD40 on Mouse and Human Renal Cell Carcinomas Triggers Cytokine Production, Leukocyte Recruitment, and Antitumor Responses that Can Be Independent of Host CD40 Expression

CD40, a member of the TNFR superfamily, is expressed on a variety of host immune cells, as well as some tumors. In this study, we show that stimulation of CD40 expressed on both mouse and human renal carcinoma cells (RCCs) triggers biological effects in vitro and in vivo. Treatment of the CD40+ Renca mouse RCC tumor cells in vitro with an agonistic anti-CD40 Ab induced strong expression of the genes and proteins for GM-CSF and MCP-1, and induced potent chemotactic activity. Similarly, administration of alphaCD40 to both wild-type and CD40-/- mice bearing Renca tumors resulted in substantial amounts of TNF-alpha and MCP-1 in the serum, increased the number of total splenocytes and MHC class II+ CD11c+ leukocytes, and when combined with IFN-gamma, inhibited the progression of established Renca tumors in vivo in both wild-type and CD40-/- mice. Similarly, treatment of CD40+ A704 and ACHN human RCC lines with mouse anti-human CD40 Ab induced strong expression of genes and proteins for MCP-1, IL-8, and GM-CSF in vitro and in vivo. Finally, in SCID mice, the numbers of ACHN pulmonary metastases were dramatically reduced by treatment with species-specific human CD40 Ab. These results show that CD40 stimulation of CD40+ tumor cells can enhance immune responses and result in antitumor activity.

CXCR3/CXCR3 ligand biological axis impairs RENCA tumor growth by a mechanism of immunoangiostasis

Metastatic renal cell carcinoma (RCC) responds poorly to chemo- or radiation therapy but appears to respond to systemic immunotherapy (i.e., IL-2 and/or IFN-alpha), albeit with only 5-10% durable response. The CXCR3/CXCR3 ligand biological axis plays an important role in mediating type 1 cytokine-dependent cell-mediated immunity, which could be beneficial for attenuating RCC if optimized. We found that systemic IL-2 induced the expression of CXCR3 on circulating mononuclear cells but impaired the CXCR3 ligand chemotactic gradient from plasma to tumor by increasing circulating CXCR3 ligand levels in a murine model of RCC. Moreover, the antitumor effect of systemic IL-2 was CXCR3-dependent, as IL-2 failed to inhibit tumor growth and angiogenesis in CXCR3-/- mice. We hypothesized that the immunotherapeutic effect of the CXCR3/CXCR3 ligand biological axis could be optimized by first priming with systemic IL-2 to induce CXCR3 expression on circulating mononuclear cells followed by enhancing the intratumor CXCR3 ligand levels to establish optimal CXCR3-dependent chemotactic gradient. We found that combined systemic IL-2 with an intratumor CXCR3 ligand (CXCL9) lead to significantly greater reduction in tumor growth and angiogenesis, increased tumor necrosis, and increased intratumor infiltration of CXCR3+ mononuclear cells, as compared with either IL-2 or CXCL9 alone. The enhanced antitumor effect of the combined strategy was associated with a more optimized CXCR3-dependent chemotactic gradient and increased tumor-specific immune response. These data suggest that the combined strategy of systemic IL-2 with intratumor CXCR3 ligand is more efficacious than either strategy alone for reducing tumor-associated angiogenesis and augmenting tumor-associated immunity, the concept of immunoangiostasis.

Fruits and vegetables and renal cell carcinoma: Findings from the European prospective investigation into cancer and nutrition (EPIC)

We examined the association between fruits and vegetables and risk of renal cell carcinoma (RCC) in the European Prospective Investigation into Cancer and Nutrition (EPIC). Dietary intake data and complete follow-up information on cancer incidence were available for 375,851 participants recruited in EPIC centers of 8 countries. During an average follow-up of 6.2 years, 306 incident cases of RCC were identified. The associations of consumption of total vegetables, total fruits, combined total fruits and vegetables and specific subtypes of vegetables with RCC risk were analyzed using Cox proportional hazards, stratified by centre and adjusted for potential confounders. No significant associations between fruit and vegetable consumption and RCC risk were observed despite a wide range of intake. The estimated relative risks (95% confidence intervals [CI]) in men and women combined were 0.97 (0.85-1.11) per 40 g increase in vegetable intake, 1.03 (0.97-1.08) per 40 g increase in fruit intake and 1.02 (0.93-1.11) per 80 g increase in fruit and vegetable intake combined. Among the vegetable subtypes, an inverse association was observed for root vegetables (RR per 8 g increase: 0.88; 95% CI: 0.78-0.99). These results suggest that total consumption of fruits and vegetables is not related to risk of RCC, although we cannot exclude the possibility that very low consumption is related to higher risk. The relationship of specific fruit and vegetable subgroups with RCC risk warrant further investigation.

Cytokine gene polymorphisms as potential risk and protective factors in renal cell carcinoma

The major aim of this study was to investigate the association of the cytokine gene polymorphisms with the development of renal cell carcinoma (RCC). The study included 29 patients with RCC and 50 healthy controls. All genotyping (TNF-alpha, TGF-beta, IL-10, IL-6, IFN-gamma) experiments were performed using sequence-specific primers PCR (PCR-SSP). It was found that TNF-alpha -308 G/G and TGF-beta codon 10-25 T/T-G/C genotypes were significantly higher in frequency in the patients with RCC group compared with the healthy control group. Additionally, the frequency of TNF-alpha -308 G allele was significantly higher in the patients when compared to controls. On the other hand, the frequencies of TNF-alpha -308 G/A, IL-6 C/C and TGF-beta1 codon 10-25 C/C-G/G genotypes were significantly lower in the cancer group compared with the healthy control group. However, after correction for multiple comparisons (Bonferroni), these results did not remain significant. Nevertheless, these findings suggest that the TNF-alpha -308 G/G and TGF-beta codon 10-25 T/T-G/C genotypes may be potential risk factors for RCC, whereas TNF-alpha -308 G/A, IL-6 C/C and TGF-beta1 codon 10-25 C/C-G/G genotypes may be possible protective factors. The number of the cases has to be increased to investigate the independency of these polymorphisms involved in the oncogenesis of RCC.

Silencing of epidermal growth factor receptor suppresses hypoxia-inducible factor-2-driven VHL-/- renal cancer

Inactivating mutations in the von Hippel-Lindau (VHL) tumor suppressor gene are associated with clear cell renal cell carcinoma (VHL-/- RCC), the most frequent malignancy of the human kidney. The VHL protein targets the alpha subunits of hypoxia-inducible factor (HIF) transcription factor for ubiquitination and degradation. VHL-/- RCC cells fail to degrade HIF resulting in the constitutive activation of its target genes, a process that is required for tumorigenesis. We recently reported that HIF activates the transforming growth factor-alpha/epidermal growth factor receptor (TGF-alpha/EGFR) pathway in VHL-defective RCC cells. Here, we show that short hairpin RNA (shRNA)-mediated inhibition of EGFR is sufficient to abolish HIF-dependent tumorigenesis in multiple VHL-/- RCC cell lines. The 2alpha form of HIF (HIF-2alpha), but not HIF-1alpha, drives in vitro and in vivo tumorigenesis of VHL-/- RCC cells by specifically activating the TGF-alpha/EGFR pathway. Transient incubation of VHL-/- RCC cell lines with small interfering RNA directed against EGFR prevents autonomous growth in two-dimensional culture as well as the ability of these cells to form dense spheroids in a three-dimensional in vitro tumor assay. Stable expression of shRNA against EGFR does not alter characteristics associated with VHL loss including constitutive production of HIF targets and defects in fibronectin deposition. In spite of this, silencing of EGFR efficiently abolishes in vivo tumor growth of VHL loss RCC cells. These data identify EGFR as a critical determinant of HIF-2alpha-dependent tumorigenesis and show at the molecular level that EGFR remains a credible target for therapeutic strategies against VHL-/- renal carcinoma.

Epigenetic modulation of retinoic acid receptor beta2 by the histone deacetylase inhibitor MS-275 in human renal cell carcinoma

PURPOSE

Histone deacetylase (HDAC) inhibitors have been shown to reverse epigenetic repression of certain genes, including retinoic acid receptor beta2 (RARbeta2). In this study, we examined whether RARbeta2 expression is repressed in human renal cell carcinoma (RCC) and whether the HDAC inhibitor MS-275 may revert its epigenetic repression.

EXPERIMENTAL DESIGN

Six human tumor RCC cell lines were analyzed for RARbeta2 gene expression and for methylation and acetylation status at the promoter level. Modulation of RARbeta2 expression and correlation with antitumor activity by combination of MS-275 with 13-cis-retinoic acid (CRA) was assessed in a RARbeta2-negative RCC cell line.

RESULTS

RARbeta2 expression was either strongly present, weakly expressed, or absent in the RCC cell lines analyzed. Methylation-specific PCR indicated that the RARbeta2 promoter was partially methylated in three of the cell lines. CRA treatment did not inhibit clonogenic growth in the RARbeta2-negative cell line RCC1.18, whereas MS-275 induced a dose-dependent inhibitory effect. A greater inhibitory effect was observed with combination treatment (MS-275 + CRA). Treatment with MS-275 was associated with histone acetylation at the promoter level and synergistic gene reexpression of RARbeta2 in combination with CRA. RARbeta2 reexpression was associated with synergistic induction of the retinoid-responsive gene HOXA5. In vivo, single-agent CRA treatment showed no significant effect, whereas MS-275 and the combination induced a regression of RCC1.18 tumor xenografts. Discontinuation of treatment produced tumor recurrence in MS-275-treated mice, whereas animals treated with the combination remained tumor free.

CONCLUSION

The HDAC inhibitor MS-275 seems to revert retinoid resistance due to epigenetic silencing of RARbeta2 in a human RCC model and has greater antitumor activity in combination with CRA compared with single agents. Thus, the combination of HDAC inhibitors and retinoids may represent a novel therapeutic approach in patients with RCC.

A Src family inhibitor (PP1) potentiates tumor-suppressive effect of connexin 32 gene in renal cancer cells

Connexin (Cx) genes exert negative growth effects on tumor cells with certain cell specificity. We have recently reported that Cx32 acts as a tumor suppressor gene in renal cancer cells due to the inhibition of Src-dependent signaling. In line with the previous study, here we examined if a Src family inhibitor (PP1) could potentiate tumor-suppressive effect of Cx32 in Caki-2 cell from human renal cell carcinoma. In order to clarify the potentialization of PP1, using Cx32-transfected Caki-2 cells and mock-transfected Caki-2 cells, we estimated difference in cytotoxic effect of PP1 on the two cell clones in vitro as well as in vivo. PP1 showed more cytotoxic effect on Caki-2 cells having Cx32 positive expression than that of Cx32 negative expression at lower doses. This potentialization was also observed in xenograft model of nude mice. The potentialization of the effect mainly depended on the induction of apoptosis but not the control of cell growth. In conjugation with this event, the reduction of anti-apoptotic molecules (Bcl-2 and Bcl-xL) was caused by the combination of Cx32 expression and PP1 treatment in Caki-2 cells. These results suggest that PP1 potentiates tumor-suppressive effect of connexin 32 gene in renal cancer cells through the reduction of anti-apoptotic molecules.

Inhibition of two stage renal carcinogenesis, oxidative damage and hyperproliferative response by Nigella sativa

In an earlier communication we reported that Nigella sativa suppresses potassium bromate-induced renal oxidative damage. In the present study, we report the chemopreventive effect of Nigella sativa against ferric nitrilotriacetate (Fe-NTA)-induced renal oxidative stress, hyperproliferative response and renal carcinogenesis. Fe-NTA (9 mg Fe/kg body weight, intraperitoneally) enhances renal lipid peroxidation, xanthine oxidase, gamma-glutamyl transpeptidase and hydrogen peroxide (H2O2) generation with reduction in renal glutathione content, antioxidant enzymes and phase II metabolizing enzymes. It also caused increase in blood urea nitrogen, serum creatinine, ornithine decarboxylase (ODC) activity and thymidine [H] incorporation into renal DNA. It also enhanced DEN (N-diethylnitrosamine)-initiated renal carcinogenesis by increasing the percentage incidence of tumours. Treatment of rats orally with Nigella sativa (50 and 100 mg/kg body weight) resulted in significant decrease in gamma-glutamyl transpeptidase, lipid peroxidation, xanthine oxidase, H2O2 generation, blood urea nitrogen, serum creatinine, renal ODC activity, DNA synthesis (P<0.001) and incidence of tumours. Renal glutathione content (P<0.01), glutathione-metabolizing enzymes (P<0.001) and antioxidant enzymes were also recovered to significant levels (P<0.001). Thus, our data suggest that Nigella sativa is a potent chemopreventive agent and suppresses Fe-NTA-induced oxidative stress, hyperproliferative response and renal carcinogenesis in Wistar rats.

SUPPRESSION OF LUNG METASTASIS OF RENAL CELL CARCINOMA BY THE INTRAMUSCULAR GENE TRANSFER OF A SOLUBLE FORM OF VASCULAR ENDOTHELIAL GROWTH FACTOR RECEPTOR I

PURPOSE

We clarified whether adenovirus mediated intramuscular gene transfer of soluble vascular endothelial growth factor receptor 1 (sFlt-1) can inhibit lung metastasis of renal cell carcinoma.

MATERIALS AND METHODS

We constructed the adenovirus vector AdsFlt-1, which expresses soluble Flt-1 protein. Functional validation of the vector was determined by HUVEC (in vitro human umbilical vein endothelial cell) proliferation inhibition assay. The efficacy of AdsFlt-1 was tested in a Renca murine renal cell carcinoma lung metastasis model. BALB/c mice were injected with Renca cells, followed by the intramuscular administration of AdsFlt-1 24 hours later. Lung specimens were harvested 17 days later and the number of lung metastases was counted. Immunohistochemical analysis of the specimen for angiogenesis and apoptosis was done.

RESULTS

Treatment with adenovirus expressed sFlt-1 inhibited HUVEC proliferation. The intramuscular administration of AdsFlt-1 significantly inhibited lung metastasis of Renca cells. Immunohistochemical analysis of the lung specimen showed fewer neovessel formations and more apoptotic cells in AdsFlt-1 treated tumors in mice.

CONCLUSIONS

The intramuscular administration of AdsFlt-1 effectively inhibited lung metastasis in a murine model of renal cell carcinoma. Because of the simplicity of this therapy, it may well be useful as an effective adjuvant therapy for renal cell carcinoma.

Fruits, vegetables and risk of renal cell carcinoma: A prospective study of Swedish women

Findings of epidemiologic studies on the relationship between fruit and vegetable consumption and renal cell carcinoma (RCC) risk have been inconclusive. To study the association between fruits and vegetables and risk of RCC in a population-based prospective cohort study of Swedish women, we collected dietary information from 61,000 women age 40-76 years by a food-frequency questionnaire. During 13.4 years of follow-up 122 women developed RCC. Cox proportional hazards models were used to estimate relative risks (RR) with 95% confidence interval (CI). Women consuming 5 or more servings of fruit and vegetables daily had a relative risk of 0.59 (95% CI = 0.26-1.34) in comparison to them consuming less than once daily. When fruits and vegetables were examined separately, those who consumed more than 75 servings per month of fruits or vegetables had multivariate relative risk of 0.59 (95% CI = 0.27-1.25) and 0.60 (95% CI = 0.31-1.17) respectively, compared to those consuming 11 or less servings per month. Within the group of fruits, the strongest inverse association was observed for banana (p = 0.07 by Wald test). The risk of RCC increased monotonically with increasing intake frequencies of fruit juice (p-value for trend = 0.10). Within the group of vegetables, the strongest inverse association was observed for root vegetables (p = 0.03 by Wald test). The risk of RCC decreased with increasing consumption frequencies of white cabbage (p for trend = 0.07). Frequent consumption of salad vegetables (once or more per day) decreased the risk by 40% (RR = 0.60; 95% CI = 0.30-1.22), in comparison to no consumption. Our results suggested that high consumption of fruits and vegetables might be associated with reduced risk of RCC.

Tumor Vaccination after Allogeneic Bone Marrow Cell Reconstitution of the Nonmyeloablatively Conditioned Tumor-Bearing Murine Host

Allogeneic bone marrow cell reconstitution of the nonmyeloablatively conditioned host is supposed to provide an optimized platform for tumor vaccination. We recently showed that an allogeneic T cell-depleted graft was well accepted if the tumor-bearing host was NK depleted. Based on this finding, a vaccination protocol in tumor-bearing, nonmyeloablatively conditioned, allogeneically reconstituted mice was elaborated. Allogeneically reconstituted mice, bearing a renal cell carcinoma, received tumor-primed donor lymph node cells (LNC), which had or had not matured in the allogeneic host. Primed LNC were supported by tumor lysate-pulsed dendritic cells, which were donor or host derived. Optimal responses against the tumor were observed with host-tolerant, tumor-primed LNC in combination with host-derived dendritic cells. High frequencies of tumor-specific proliferating and CTLs were recorded; the survival time of tumor-bearing mice was significantly prolonged, and in >50% of mice the tumor was completely rejected. Notably, severe graft-vs-host disease was observed in reconstituted mice that received tumor-primed LNC, which had not matured in the allogeneic host. However, graft-vs-host was not aggravated after vaccination with tumor-primed, host-tolerant LNC. Thus, the LNC were tolerant toward the host, but not toward the tumor. The finding convincingly demonstrates the feasibility and efficacy of tumor vaccination after allogeneic reconstitution of the nonmyeloablatively conditioned host.

Induction of antigen specific cellular immunity by vaccination with peptides from MN/CA IX in renal cell carcinoma

We investigated the induction of the specific immunity for renal cell carcinomas (RCC) using MN/CA IX, a tumor-associated antigen frequently expressed in RCC. We have generated 9-mer peptide derived from MN/CA IX and examined the antigenicity as a vaccine to induce specific immunity for RCC. To use mouse syngeneic system, we transfected human MN/CA9 cDNA into RenCa and BALB-3T3 cells originally from BALB/c mouse, and established MN/CA IX expressing mouse cell lines, i.e., MN-RenCa and MN-3T3. The immunization of BALB/c mouse with MN-RenCa cells resulted in the induction of cytotoxic T lymphocytes (CTL) against MN/CA IX expressing cells and the CTL clone was established from bulked CTL. This CTL clone specifically lyzed MN-3T3 cells, but not parental cells. To identify the targeted epitope binding to H-2Kd antigen, three 9-mer peptides (A, B, C-peptide) of human MN/CA IX compatible with the H-2Kd as well as HLA-A24 binding motif was synthesized. The cloned CTL targeted the B-peptide pulsed BALB-3T3 cells as well as MN-3T3 cells. Furthermore, spleen cells from BALB/c mouse immunized with B-peptide reacted against MN-RenCa cells. These results suggest that the peptides derived from MN/CA IX containing HLA-A24 binding motif may be useful as a potent tumor vaccine for the treatment of human RCC, and in mouse models.

Blockade of epidermal growth factor receptor signaling leads to inhibition of renal cell carcinoma growth in the bone of nude mice

Renal cell carcinoma (RCC) frequently produces metastases to the musculoskeletal system that are a major source of morbidity in the form of pain, immobilization, fractures, neurological compromise, and a decreased ability to perform activities of daily living. Patients with metastatic RCC therefore have a dismal prognosis because there is no effective adjuvant treatment for this disease. Because the epidermal growth factor receptor (EGF-R) signaling cascade is important in the growth and metastasis of RCC, its blockade has been hypothesized to inhibit tumor growth and hence prevent resultant bone destruction. We determined whether blockade of EGF-R by the tyrosine kinase inhibitor PKI 166 inhibited the growth of RCC in bone. We use a novel cell line, RBM1-IT4, established from a human RCC bone metastasis. Protein and mRNA expression of the ligands and receptors was assessed by Western and Northern blots. The stimulation of RBM1-IT4 cells with epidermal growth factor or transforming growth factor alpha resulted in increased cellular proliferation and tyrosine kinase autophosphorylation. PKI 166 prevented these effects. First, RBM1-IT4 cells were implanted into the tibia of nude mice, where they established lytic, progressively growing lesions, after which the mice were treated with PKI 166 alone or in combination with paclitaxel (Taxol). Immunohistochemical analysis revealed that tumor cells and tumor-associated endothelial cells in control mice expressed activated EGF-R. Treatment of mice with PKI 166 alone or in combination with Taxol produced a significant decrease in the incidence and size of bone lesions as compared with the results in control or Taxol-treated mice (P < 0.001). Treatment with PKI 166 also decreased the expression of phosphorylated EGF-R by tumor cells and tumor-associated endothelial cells, and this was even more pronounced with PKI 166 plus Taxol treatment. The PKI 166 plus Taxol combination produced apoptosis of tumor cells and tumor-associated endothelial cells. Tumor cell proliferation, shown by proliferating cell nuclear antigen positivity, was decreased in all treatment groups. In addition, the integrity of the bone was maintained in mice treated with PKI 166 or PKI 166 plus Taxol, whereas massive bone destruction was seen in control and Taxol-treated mice. These results suggest that blockade of EGF-R signaling inhibits growth of RCC in the bone by its effect on tumor cells and tumor-associated endothelial cells.

Does growth hormone treatment affect the risk of post-transplant renal cancer?

According to the analysis of the Collaborative Transplant Study (CTS), the incidence of renal carcinoma in patients with renal transplantation as well as with heart transplantation is significantly increased at any given patient age. The cumulative incidence 10 years after kidney transplantation is 185 per 100,000 patients in children below the age of 19 years at the time of transplantation. Age and immunosuppressive treatment seem to be the major risk factors. The majority of cancers develop within the native kidneys. Chronic transplant nephropathy and accelerated senescence may be further risk factors for the development of cancer within a kidney transplant. Growth hormone (GH) treatment could not be identified as an additional risk factor.

Isoliquiritigenin suppresses pulmonary metastasis of mouse renal cell carcinoma

Isoliquiritigenin is a chalcone isolated from licorice and shallots. The ability of isoliquiritigenin to suppress metastasis was examined in a pulmonary metastasis model of mouse renal cell carcinoma. Isoliquiritigenin significantly reduced pulmonary metastasis, without any weight loss or leukocytopenia. Isoliquiritigenin suppressed in vitro proliferation of carcinoma cells, potentiated nitric oxide production by lipopolysaccharide-stimulated macrophages, and facilitated cytotoxicity of splenic lymphocytes in vitro. These findings suggest activation of macrophages, activation of cytotoxicity of lymphocytes, and direct cytotoxicity as possible mechanisms of metastasis suppression by isoliquiritigenin. In addition, isoliquiritigenin prevented severe leukocytopenia caused by administration of 5-fluorouracil.

Electrotransfer of gene encoding endostatin into normal and neoplastic mouse tissues: inhibition of primary tumor growth and metastatic spread

Electroporation-mediated gene transfer relies upon direct delivery of plasmids into cells permeabilized by electric fields, a method more efficient than transfer using nonviral vectors, although neither approaches the transfer efficiency of viral vectors. Here we studied electrotransfer of a gene encoding an angiogenesis inhibitor (endostatin) into primary tumors and muscle tissues, which would serve as a site of synthesis and secretion into the bloodstream of a therapeutic antimetastatic protein with systemic effects. Optimum electroporation conditions (voltage, number and duration of impulses, separation of caliper electrodes) were first established to maximize expression of a reporter gene transferred into murine Renca kidney carcinoma, B16(F10) melanoma, or skeletal muscle tissues. In neoplastic tissues, electrotransfer of plasmid DNA was far more efficient than electroporation with lipoplexes, but no differences between naked DNA and lipoplexes were found in case of electroporated muscles. We then studied the electrotransfer of plasmid DNA carrying the endostatin gene into pre-established experimental Renca tumors. A significant inhibition of tumor growth was observed in animals electroporated with this construct. Electrotransfer of the endostatin gene into muscle tissues resulted in reduced numbers of experimental B16(F10) metastases in the lungs. This study clearly shows that electroporation may be used to efficiently transfer antiangiogenic genes into both normal and neoplastic tissues.

Effect of a matrix metalloproteinase inhibitor (ONO-4817) on lung metastasis of murine renal cell carcinoma

We examined the anti-metastatic effect of a newly developed inhibitor of synthetic matrix metalloproteinase (MMP), ONO-4817, on experimental pulmonary metastasis of murine renal cell carcinoma (Renca) cells and on tumor cell invasion, through reconstituted basement membrane (Matrigel) in vitro using the same cells. Oral administration of ONO-4817 (50-200 mg/kg/day) to Renca-bearing mice resulted in a dose-dependent inhibition of lung metastasis without a loss of body weight. ONO-4817 at the high dose of 200 mg/kg showed a tendency to prolong the survival of the mice. We also found that oral administration of ONO-4817 significantly inhibited the angiogenic response (number of vessels oriented towards the tumor mass) and the growth of tumors inoculated i.d. in syngeneic mice. In addition, ONO-4817, at non-cytotoxic concentrations of less than 10 microM, caused a marked inhibition of the invasion of Renca cells as compared to the vehicle control. Gelatin zymography revealed that ONO-4817 inhibited the enzymatic activity of MMP-2 produced by Renca cells in a concentration-dependent manner. In conclusion, ONO-4817 effectively inhibited lung metastasis of Renca cells through its anti-invasive and anti-angiogenic properties. These results suggest that use of the MMP inhibitor (MMPI) ONO-481 7 may provide a therapeutic basis for preventing lung recurrence and metastasis of renal cell carcinoma.

Gamma/delta T cells provide innate immunity against renal cell carcinoma

Host immune function plays a certain role against the development of renal cell carcinomas (RCCs), but the mechanism is not entirely understood. Human gamma/delta (gamma/delta) T cells defend the body against infection. In this study, we clarify the role of gamma/delta T cells in the surveillance system against RCCs by analyzing the gamma/delta T cells in peripheral blood mononucleocytes (PBMs) and tumor infiltrating lymphocytes (TILs) from 41 patients with RCCs. The results showed that the number of gamma/delta T cells expressing V gamma 2 and V delta 2 in variable elements of TCR was elevated in the PBMs in 10 patients, but not in any of 32 healthy individuals. The proportion of patients with an elevated number of gamma/delta T cells (> 10%) increased with cancer stage. The level of the gamma/delta T cells decreased after surgery. The gamma/delta T cells in the TILs were more activated than those in the PBMs. Evaluation of the junctional diversity of TCR V gamma 2 and V delta 2 chains showed that the increased peripheral blood gamma/delta T cells were oligoclonal rather than polyclonal. Taken together, our findings suggest that gamma/delta T cells recognize certain RCC-related antigens and play a role in the surveillance system against RCCs.