Application of Hereditary Renal Cell Carcinoma Risk Criteria to a Large Prospective Database.

AIMS: To evaluate the clinical impact of the Canadian criteria for identifying patients and families at risk for hereditary renal cell carcinoma (RCC). MATERIALS AND METHODS: The Canadian hereditary RCC risk criteria were applied to patients from 16 centres in the Canadian Kidney Cancer information system (CKCis) prospective database. The primary end point was the proportion of patients who met at least one criterion. RESULTS: Between January 2011 and May 2017, 8388 patients were entered in the database; 291 had inadequate risk data; 2827 (35%) met at least one criterion for genetic testing (at-risk population). Most (83%) met just one criterion. The criterion of non-clear cell histology contributed the largest proportion of at-risk patients (59%), followed by age ≤ 45 years (28%). Sixty-one patients had documentation of genetic testing, with 56 being classified at-risk (2% of at-risk). Twenty patients (35%) of the patients at risk and tested for hereditary RCC were found to harbour a germline mutation. CONCLUSIONS: Application of the Canadian hereditary RCC risk criteria to a large prospective database resulted in 35% of patients being identified at risk for hereditary RCC who could qualify for genetic testing. However, the true incidence of hereditary RCC in this population is unknown as most patients did not have documented genetic testing carried out and, thus, the sensitivity and specificity of the criteria cannot be determined. The low proportion of at-risk patients who underwent genetic testing is disappointing and highlights that there may be gaps in reporting, knowledge and/or barriers in access to genetic testing.

Renal cell carcinoma in the Canadian Indigenous population.

Background: Diagnosis and treatment of renal cell carcinoma (rcc) might be different in Indigenous Canadians than in non-Indigenous Canadians. In this cohort study, we compared rcc presentation and treatments in Indigenous and non-Indigenous Canadians. Methods: Patients registered in the Canadian Kidney Cancer Information System treated at 16 institutions between 2011 and 2018 were included. Baseline patient, tumour, and treatment characteristics were compared between Indigenous and non-Indigenous Canadians. The primary objective was to determine if differences in rcc stage at diagnosis were evident between the groups. The secondary objective was to determine if treatments and outcomes were different between the groups. Results: During the study period, 105 of the 4529 registered patients self-identified as Indigenous. Those patients were significantly younger at the time of clinical diagnosis (57.9 ± 11.3 years vs. 62.0 ± 12.1 years, p = 0.0006) and had a family history prevalence of rcc that was double the prevalence in the non-Indigenous patients (14% vs. 7%, p = 0.004). Clinical stage at diagnosis was similar in the two groups (p = 0.61). The disease was metastatic at presentation in 11 Indigenous Canadians (10%) and in 355 non-Indigenous Canadians (8%). Comorbid conditions that could affect the management of rcc-such as obesity, renal disease, diabetes mellitus, and smoking-were more common in Indigenous Canadians (p < 0.05). Indigenous Canadians experienced a lower rate of active surveillance (p = 0.01). Treatments and median time to treatments were similar in the two groups. Conclusions: Compared with their non-Indigenous counterparts, Indigenous Canadian patients with rcc are diagnosed at an earlier age and at a similar clinical stage. Despite higher baseline comorbid conditions, clinical outcomes are not worse for Indigenous Canadians than for non-Indigenous Canadians.

A LATS biosensor screen identifies VEGFR as a regulator of the Hippo pathway in angiogenesis.

The Hippo pathway is a central regulator of tissue development and homeostasis, and has been reported to have a role during vascular development. Here we develop a bioluminescence-based biosensor that monitors the activity of the Hippo core component LATS kinase. Using this biosensor and a library of small molecule kinase inhibitors, we perform a screen for kinases modulating LATS activity and identify VEGFR as an upstream regulator of the Hippo pathway. We find that VEGFR activation by VEGF triggers PI3K/MAPK signaling, which subsequently inhibits LATS and activates the Hippo effectors YAP and TAZ. We further show that the Hippo pathway is a critical mediator of VEGF-induced angiogenesis and tumor vasculogenic mimicry. Thus, our work offers a biosensor tool for the study of the Hippo pathway and suggests a role for Hippo signaling in regulating blood vessel formation in physiological and pathological settings.

Role of Smad1 and Smad4 proteins in the induction of p21WAF1,Cip1 during bone morphogenetic protein-induced growth arrest in human breast cancer cells.

Bone morphogenetic proteins (BMPs) are members of the transforming growth factor-beta family of cytokines. The recent observation that BMPs can inhibit breast cancer cell proliferation in vitro suggests that BMPs or the BMP pathway may hold promise as therapeutic targets for the control of breast tumor growth in women. Better to understand the mechanism of BMP-induced growth arrest we examined the effect of BMP-2 and mediators of BMP-2 action on cell proliferation and p21(Cip1) expression in breast cancer cell lines. We show here that BMP-2 potently inhibited the proliferation of breast cancer cell lines that express both Smad1 and Smad4 (CAMA-1, MCF7, MDA-MB-231, T-47D, ZR-75-1), but not that of cells that only express Smad1 (MDA-MB-468). Growth inhibition correlated with up-regulation of p21 mRNA and protein levels. Up-regulation of p21 was resistant to cycloheximide but not to actinomycin D, suggesting that it occurred at the transcriptional level. Using p21 promoter-luciferase reporter constructs we mapped the BMP-responsive region of the p21 promoter to within 211 base pairs of the transcription start site. Induction of p21 promoter activity was rapid and coincided with up-regulation of p21 mRNA and protein levels. p21 promoter activity required both Smad1 and Smad4 and was induced by either BMP-2 or constitutively active type I BMP receptors. Moreover, the C-terminal SSVS region of Smad1 was necessary for activation of the p21 promoter by BMP-2. Taken together, these results indicate that the mechanism of BMP-induced p21 promoter activation involves BMP receptors and BMP Smads.

Expression profile of agonistic Smads in human breast cancer cells: absence of regulation by estrogens.

Transforming growth factor-beta1 (TGF-beta1) is a cytokine expressed by mammary cells. While TGF-beta1 can inhibit the proliferation of human breast cancer cells, many cell lines are unresponsive to it. To shed light on the mechanisms underlying resistance to TGF-beta1, we examined expression of the mediators of TGF-beta1 signaling in the mammary carcinoma cell lines MCF-7, T47D, ZR-75-1, BT-20, MDA-MB-231 and MDA-MB-468. The levels of mRNA encoding Smad2, 3 and 4 as well as the type II (TbetaRII) and type I (TbetaRI) membrane receptors were determined by Northern analysis and/or ribonuclease protection assays. Smad2 and Smad3 mRNAs were detected in all 6 cell lines examined, whereas Smad4 mRNA was not detected in MDA-MB-468 cells, which are known to harbor a homozygous deletion of the Smad4 gene. TbetaRI was expressed in all 6 cell lines, whereas TbetaRII was not detected in ZR-75-1 and T47D cells. Of the cell lines tested, only MCF-7 cells were growth-inhibited by TGF-beta1. In contrast, only MDA-MB-231 cells showed induction of the PAI-1 promotor in response to TGF-beta1. We also examined the regulation of Smad mRNA expression by estrogens and androgens in ZR-75-1 cells. Neither estradiol nor dihydrotestosterone affected Smad2, 3 or 4 mRNA levels in ZR-75-1 cells. These results indicate that the lack of response to TGF-beta1 in the breast cancer cell lines examined can be attributed to the absence of either TbetaRII or the Smad4 gene product. Moreover, we show that the proliferative and transcriptional responses to TGF-beta1 are dissociable and that Smad expression is not regulated by sex steroids in ZR-75-1 cells.

Structure of the gene encoding the human cyclin-dependent kinase inhibitor p18 and mutational analysis in breast cancer.

The cyclin-dependent kinase (CDK) inhibitor p18 blocks progression of the cell cycle by associating with the cyclin D-dependent kinases CDK6 and CDK4. To better understand the regulation of p18 gene expression, we isolated full-length cDNA clones from a human BT-20 breast cancer cell cDNA library. These clones were then used to isolate the human gene from a human genomic DNA library. The human p18 gene spans at least 7.5 kb and is composed of three exons, two of which encode the p18 protein. The genomic clone we isolated contained 5 kb of putative promotor sequence which directed expression of the luciferase reporter gene in transient transfection experiments. The longest cDNA that we isolated from BT-20 cells contained 2103 nucleotides which corresponds to the size of the major RNA transcript detected by Northern analysis in these cells. Transcription start sites mapping to the 5' end of the putative full-length cDNA were identified by ribonuclease protection assays. A novel polymorphism was identified in the 3' untranslated region of BT-20 cell cDNA clones that contained the previously described codon 72 mutation. The codon 72 mutation was also detected in 3 of 35 breast tumors analyzed using a mismatch PCR/RFLP strategy.

Effect of dehydroepiandrosterone and the antiestrogen EM-800 on growth of human ZR-75-1 breast cancer xenografts.

BACKGROUND: In the mammary gland, androgens are formed from the precursor steroid dehydroepiandrosterone (DHEA). Clinical evidence indicates that androgens have inhibitory effects on breast cancer. Estrogens, on the other hand, stimulate the development and growth of breast cancer. We studied the effect of DHEA alone or in combination with the newly described pure antiestrogen EM-800 on the growth of subcutaneous tumor xenografts formed by the human breast cancer cell line ZR-75-1 in ovariectomized nude mice. METHODS: Immediately after ovariectomy, mice received daily subcutaneous injections of 0.5 microg estrone (E1) (an estrogenic hormone). EM-800 (15, 50, or 100 microg) was given orally once daily. DHEA was administered percutaneously twice daily (total dose of 0.3, 1.0, or 3.0 mg) to the dorsal skin either alone or in combination with a 15-microg daily oral dose of EM-800. Changes in tumor size in response to the treatments (in relation to measurements made on the first day of treatment) were assessed periodically. At the end of the experiments, tumors were dissected and weighed. RESULTS: A 9.4-fold increase in tumor size in 9.5 months was observed in ovariectomized mice receiving E1 alone. Administration of 15, 50, or 100 microg EM-800 in E1-supplemented mice led to inhibitions of 87.5%, 93.5%, and 94.0% in tumor size, respectively. DHEA, on the other hand, at doses of 0.3, 1.0, or 3.0 mg inhibited terminal tumor size by 50.4%, 76.8%, and 80.0%, respectively. Comparable inhibitions in tumor size were obtained with a daily 15-microg oral dose of EM-800 with or without different doses of percutaneous DHEA. CONCLUSIONS: DHEA and EM-800 independently suppressed the growth of E1-stimulated ZR-75-1 xenograft tumors in nude mice. Administration of DHEA at the defined doses did not alter the inhibitory effect of EM-800.