Prostate Tumor Overexpressed-1 (PTOV1) promotes docetaxel-resistance and survival of castration resistant prostate cancer cells

Metastatic prostate cancer is presently incurable. The oncogenic protein PTOV1, first described in prostate cancer, was reported as overexpressed and significantly correlated with poor survival in numerous tumors. Here, we investigated the role of PTOV1 in prostate cancer survival to docetaxel and self-renewal ability. Transduction of PTOV1 in docetaxel-sensitive Du145 and PC3 cells significantly increased cell survival after docetaxel exposure and induced docetaxel-resistance genes expression (ABCB1, CCNG2 and TUBB2B). In addition, PTOV1 induced prostatospheres formation and self-renewal genes expression (ALDH1A1, LIN28A, MYC and NANOG). In contrast, Du145 and PC3 cells knockdown for PTOV1 significantly accumulated in the G2/M phase, presented a concomitant increased subG1 peak, and cell death by apoptosis. These effects were enhanced in docetaxel-resistant cells. Analyses of tumor datasets show that PTOV1 expression significantly correlated with prostate tumor grade, drug resistance (CCNG2) and self-renewal (ALDH1A1, MYC) markers. These genes are concurrently overexpressed in most metastatic lesions. Metastases also show PTOV1 genomic amplification in significant co-occurrence with docetaxel-resistance and self-renewal genes. Our findings identify PTOV1 as a promoter of docetaxel-resistance and self-renewal characteristics for castration resistant prostate cancer. The concomitant increased expression of PTOV1, ALDH1A1 and CCNG2 in primary tumors, may predict metastasis and bad prognosis.

Spinophilin acts as a tumor suppressor by regulating Rb phosphorylation

The scaffold protein Spinophilin (SPN) is a regulatory subunit of phosphatase1a located at 17q21.33. This region is frequently associated with microsatellite instability and LOH containing a relatively high density of known tumor suppressor genes, including BRCA1. Several linkage studies have suggested the existence of an unknown tumor suppressor gene distal to BRCA1. Spn may be this gene, but the mechanism through which this gene makes its contribution to cancer has not been described. In this study, we aimed to determine how loss of Spn may contribute to tumorigenesis. We explored the contribution of SPN to PP1a-mediated Rb regulation. We found that the loss of Spn downregulated PPP1CA and PP1a activity, resulting in a high level of phosphorylated Rb and increased ARF and p53 activity. However, in the absence of p53, reduced levels of SPN enhanced the tumorigenic potential of the cells. Furthermore, the ectopic expression of SPN in human tumor cells greatly reduced cell growth. Taken together, our results demonstrate that the loss of Spn induces a proliferative response by increasing Rb phosphorylation, which, in turn, activates p53, thereby neutralizing the proliferative response. We suggest that Spn may be the tumor suppressor gene located at 17q21.33 acting through Rb regulation.

[Attitude of the adult patient with atopic dermatitis to the disease and its treatment: the ACTIDA Study]

OBJECTIVE

To determine the attitude of adult patients with atopic dermatitis (AD) to their disease and its treatment.

MATERIAL AND METHODS

A multicenter, cross-sectional study was performed in patients with at least 2 outbreaks of AD in the previous year.

RESULTS

Two hundred twenty-seven dermatologists recruited 1441 analyzable patients, the majority women, with a mean of 3.6 outbreaks per year. Most of the patients (97.2%) indicated that they always or sometimes requested medical evaluation of a new outbreak. In the most recent outbreak, 72.2% had used combined therapy, regardless of the severity of the episode; 2-drug combinations were the most common. The majority of dermatologists prescribed combined therapy, most commonly a 2-drug combination for mild or minimal disease, and 3 or more drugs for moderate to very severe outbreaks.

CONCLUSIONS

Treatments used by patients for an outbreak of AD are similar to those prescribed by dermatologists in recent outbreaks.

Regulation of replicative and stress-induced senescence by RSK4, which is down-regulated in human tumors

PURPOSE

The control of senescence and its biochemical pathways is a crucial factor for understanding cell transformation. In a large RNA interference screen, the RSK4 gene was found to be related to p53-dependent arrest. The purpose of the present study was to investigate the potential role of RSK4 as a tumor suppressor gene.

EXPERIMENTAL DESIGN

RSK4 expression was determined by quantitative real-time PCR and immunoblot in 30 colon and 20 renal carcinomas, and in 7 colon adenomas. Two HCT116 colon carcinoma cell lines (p53 wt and p53 null), IMR90 human fibroblasts, and E1A-expressing IMR90 cells were infected with RSK4 cDNA and/or shRNA. RSK4 expression levels were analyzed in HCT116 p53 wt or p53 null and IMR90 after senescence induction by quantitative real-time PCR and Western blot.

RESULTS

The RSK4 gene was down-regulated in 27 of 30 colon carcinomas (P < 0.001), 16 of 20 renal cell carcinomas (P < 0.01), and 6 of 7 colon adenomas (P < 0.01). In vitro overexpression of RSK4 induced cell arrest and senescence features in normal fibroblasts and malignant colon carcinoma cell lines. Interestingly, in these cell lines RSK4 mRNA levels were increased both in replicative and stress-induced senescence. Moreover, IMR90 partially immortalized by RSK4 shRNA and HCT116 with this short hairpin RNA were more resistant to cisplatin treatment. Finally, cells expressing E1A or Rb short interfering RNA were resistant to RSK4-mediated senescence.

CONCLUSION

These results support the concept that RSK4 may be an important tumor suppressor gene by modulating senescence induction and contributing to cell proliferation control in colon carcinogenesis and renal cell carcinomas.

PPP1CA contributes to the senescence program induced by oncogenic Ras

Ectopic expression of conditional murine p53 (p53val135) and oncogenic ras is enough to induce a senescent-like growth arrest at the restrictive temperature. We took advantage of this cellular system to identify new key players in the ras/p53-induced senescence. Applying a retroviral-based genetic screen, we obtained an antisense RNA fragment against PPP1CA, the catalytic subunit of protein phosphatase 1alpha, whose loss of function bypasses ras/p53-induced growth arrest and senescence. Expression of a specific short hairpin (sh)RNA against PPP1CA impairs the p53-dependent induction of p21 after DNA damage and blocks the subsequent pRb dephosphorylation, thus bypassing p53-induced arrest. We found that oncogenic ras promotes an increase in the intracellular level of ceramides together with an increase in the PPP1CA protein levels. Addition of soluble ceramide to the cells induced a senescence phenotype that is blocked through PPP1CA downregulation by specific shRNA. Analysis of human tumors suggests that one of the PPP1CA alleles might be lost in a high percentage of carcinomas such as kidney and colorectal. The overexpression of two out of five PPP1CA alternative spliced variants reduced tumor cell growth and the downregulation of the protein to hemizygosity increased the anchorage-independent growth. We propose that oncogenic stress induced by ras causes ceramide accumulation, therefore, increasing PPP1CA activity, pRb dephosphorylation and onset of the p53-induced arrest, contributing to tumor suppression.

[Clinical and therapeutic profile and quality of life of patients with seborrheic dermatitis]

INTRODUCTION

The clinical characteristics of seborrheic dermatitis (SD), therapeutic strategies employed in current clinical practice and impact on the quality of life in the Spanish population are described.

METHODS

An epidemiological, multicenter, transversal study in patients older than 16 years with seborrheic dermatitis. We evaluated the intensity of symptoms (scale 0-4), and impact on the quality of life by the Skindex-29 questionnaire (scale 0-100).

RESULTS

Two thousand one hundred and fifty nine patients participated, the mean age was 43,6 years, 55 % were men and 42 % had a family history of seborrheic dermatitis. Diagnosis is usually carried out at a mean age of 33,7 years. The median number of outbreaks in the last year is three. The median duration of each outbreak is 14 days. The most involved areas are the face (88 %) and scalp (70 %). The mean intensities are as follows: scaling 1.9, erythema 1.89, pruritus 1.73, oily skin 1.52, and induration 0.87. Ninety-eight percent of patients report a trigger factor for outbreaks, namely stress/depression/fatigue (76 %) and seasonal variation (44 %). Acne is the most common concomitant disease (35 %). The most common treatments are topical steroids (60 %), imidazole antifungals (35 %) and hydratating/nutritive products (31 %). The mean Skindex-29 global score is 20.5.

CONCLUSIONS

The most common clinical profile of seborrheic dermatitis is a 40-year-old patient with facial/scalp involvement of mild to moderate intensity with a history of stress/depression/fatigue prior to the outbreak. The most common treatments in the daily clinical practice are topical steroids and imidazole antifungals. The impact of seborrheic dermatitis in the quality of life is low.

[Observational study to evaluate the impact of an educational/informative intervention in the emotional status (anxiety) of patients with atopic dermatitis (CUIDA-DEL)]

INTRODUCTION

One of the first therapeutic measures in atopic dermatitis should be the educational and informative approach about prophylactic aspects and evolution of the disease. This type of proceedings has been shown to be beneficial for the anxious type of emotional status in patients with atopic dermatitis. We evaluated the impact of an educational/informative intervention in the emotional status (anxiety) of patients with atopic dermatitis in Spain.

MATERIAL AND METHODS

Investigators were randomized into two study groups: the control group (CG) that followed current clinical practice and the intervention group (IG) that handed patients, in each visit, a booklet of information about different prophylactic aspects and care of atopic dermatitis. The duration of the study was 6 months with quarterly visits. All included patients had a diagnosis of atopic dermatitis. Anxiety was evaluated with the STAI anxiety questionnaire and clinical data regarding dermatological aspects (IGA, pruritus scale, location of the lesions) were also recorded.

RESULTS

A total of 1,247 patients were recruited thanks to the collaboration of 158 investigators. Patients were distributed as follows: 683 (54.7 %) in the CG and 564 (45.2 %) in the IG. Both group were homogeneous with respect to basal characteristics, and were constituted by 54 % of women with a mean age of 19 years. Eighty-six percent of atopic dermatitis lesions were preferentially located in extremities. Patients of both study groups showed improvement in their emotional status (trait and state anxiety) throughout the study with significant decreases in the STAI scores compared to basal ones. Regarding improvement in the questionnaire scores, no significant differences were observed between groups except in children aged 9 to 15 years, in the pediatric version of the STAI trait where the percentage of score decrease at 6 months adjusted to the basal score was 5.5 (19.0) for the CG and 10.6 (18.9) for the IG, (p < 0.05). A higher percentage of patients finished the study in the IG compared to the CG (83.1 % vs. 76.1 % p < 0.005).

DISCUSSION AND CONCLUSIONS

Although patients in the IG showed greater compliance with the follow-up of the study, the informative intervention about prophylactic aspects of atopic dermatitis designed in this study does not appear to have had an impact in improving the emotional status of adult patients.

MAP17 overexpression is a common characteristic of carcinomas

We undertook a large-scale genetic screen to identify genes able to alter the cellular response to physiological signals and provide selective advantage once tumorigenesis has begun. We identified MAP17, a small 17 kDa non-glycosylated membrane protein previously identified, being overexpressed in carcinomas. We found that MAP17 is overexpressed in a great variety of human carcinomas. Immunohistochemical analysis of MAP17 during cancer progression shows, at least in prostate and ovarian carcinomas, that overexpression of the protein strongly correlates with tumoral progression (P < 0.0001). Many tumor cells also express MAP17 and its expression does not correlate with expression of SCL, a neighbor gene reported to be co-expressed in some hematopoietic cell lines. SCL neither is expressed in most MAP17-positive tumors, indicating the independent transcription of MAP17, at least in carcinomas. We cloned 5' genomic region to MAP17 and described the minimal promoter necessary to produce independent activation of MAP17. Moreover, we have found that MAP17 promoter is activated by oncogenes. Taken together, our data show an independent activation of MAP17 promoter that can be driven by oncogenes and that might explain the common overexpression of MAP17 in human carcinomas.

MAP17 enhances the malignant behavior of tumor cells through ROS increase

Tumorigenesis occurs when the mechanisms involved in the control of tissue homeostasis are disrupted and cells stop responding to physiological signals. Therefore, genes capable of desensitizing tumoral cells from physiological signals may provide a selective advantage within the tumoral mass and influence the outcome of the disease. We undertook a large-scale genetic screen to identify genes able to alter the cellular response to physiological signals and provide selective advantage once tumorigenesis has begun. We identified MAP17, a small 17 kDa non-glycosylated membrane protein previously identified by differential display being over-expressed in carcinomas. Tumor cells that over-express MAP17 show an increased tumoral phenotype with enhanced proliferative capabilities both in presence or absence of contact inhibition, decreased apoptotic sensitivity and increased migration. MAP17-expressing clones also grow better in nude mice. The increased malignant cell behavior induced by MAP17 are associated with an increase in reactive oxygen species (ROS) production, and the treatment of MAP17-expressing cells with antioxidants results in a reduction in the tumorigenic properties of these cells. Treatment of melanoma cells with inhibitors of Na+-coupled co-transporters lead to an inhibition of ROS increase and a decrease in the malignant cell behavior in MAP17-expressing clones. Finally, we show that MAP17-dependent ROS increase and tumorigenesis are dependent on its PDZ-binding domain, since disruption of its sequence by point mutations abolishes its ability to enhance ROS production and tumorigenesis. Our work shows the tumorigenic capability of MAP17 through a connection between Na+-coupled co-transporters and ROS.

Immortalization of primary human prostate epithelial cells by c-Myc

A significant percentage of prostate tumors have amplifications of the c-Myc gene, but the precise role of c-Myc in prostate cancer is not fully understood. Immortalization of human epithelial cells involves both inactivation of the Rb/p16INK4a pathway and telomere maintenance, and it has been recapitulated in culture by expression of the catalytic subunit of telomerase, hTERT, in combination with viral oncoproteins. Here, we show the immortalization of human prostate epithelial cells (HPrEC) by a single genetic event, the expression of the c-Myc oncogene. Myc stabilizes telomere length in HPrEC through up-regulation of hTERT expression and overrides the accumulation of cell cycle inhibitory proteins, such as p16INK4a. Overall, HPrECs expressing c-Myc retain many characteristics of normal cells, such as the induction of a senescence-like growth arrest in response to oncogenic Ras, an intact p53 response, and an absence of gross karyotypic abnormalities. However, HPrECs expressing c-Myc lack a Rb/p16INK4a checkpoint and can be transformed without the need for additional genetic lesions in that pathway. These results give a partial explanation for the physiologic role of c-Myc overexpression in prostate cancer.

Disruption of Trrap causes early embryonic lethality and defects in cell cycle progression

The transactivation/transformation-domain associated protein (TRRAP) belongs to the Ataxia-telangiectasia mutated (ATM) super-family and has been identified as a cofactor for c-MYC-mediated oncogenic transformation. TRRAP and its yeast homolog (Tra1p) are components of histone acetyltransferase (HAT) complexes, SAGA (refs. 2,4,5), PCAF (ref. 3) and NuA4 (ref. 6), which are important for the regulation of transcription and cell cycle progression and also have a role in cell viability. Yet the biological function of this molecule and how it controls proliferation are still unclear. Here we show that null mutation of Trrap in mice results in peri-implantation lethality due to a blocked proliferation of blastocysts. We use an inducible Cre-loxP system to show that loss of Trrap blocks cell proliferation because of aberrant mitotic exit accompanied by cytokinesis failure and endoreduplication. Trrap-deficient cells fail to sustain mitotic arrest despite chromosome missegregation and disrupted spindles, and display compromised cdk1 activity. Trrap is therefore essential for early development and required for the mitotic checkpoint and normal cell cycle progression.

In vivo radiosensitizing effect of the adenovirus E1A gene in murine and human malignant tumors

The adenovirus E1A gene is a potent inducer of chemosensitivity and radiosensitivity through p53-dependent and independent mechanisms. We have studied the sensitivity of murine (MSC11A5, a sarcomatoid epidermoid carcinoma) and human (HeLa, human cervix carcinoma) E1A-expressing tumors, in vivo, after treatment with cisplatin or gamma-irradiation. In athymic mice, half-body irradiation was performed in an AECL Cobalt unit, at an SSD of 80 cm. Daily fractions of 300 cGy over 3 days, up to a total dose of 9 Gy. Cisplatin was injected intraperitoneally at a dose of 9 mg per kg of body weight. After gamma-irradiation or intraperitoneal injection of cisplatin, about 30% of the E1A-expressing tumors regressed completely or were associated with a marked decrease in tumorigenicity over the following weeks. We conclude that malignant tumors, when expressing adenovirus E1A, are very sensitive to treatment with DNA-damaging agents, in vivo, regardless of the p53 status of the tumors.

Adenovirus lacking the 19-kDa and 55-kDa E1B genes exerts a marked cytotoxic effect in human malignant cells

The adenovirus (Ad) E1A gene exerts an antitumor effect and can induce sensitivity to treatment with DNA-damaging agents. In contrast, the Ad 19-kDa E1B protein inhibits E1A-mediated apoptosis and the 55-kDa E1B inactivates the p53 protein. In this paper, we study the in vitro and in vivo effects of a 19-kDa and 55-kDa E1B-defective Ad in several malignant human tumor cell lines.

MATERIALS AND METHODS

Nontumorigenic human fibroblasts (CCD-45SK and Hs67), peripheral blood lymphocytes, and several human tumor cell lines derived from cervix, colon, and breast carcinomas, epidermoid carcinoma, and osteosarcoma (HeLa, HT29, MCF7, Saos-2, and A431 cell lines) were studied. Wild-type (wt) Ad type 5 and H5 dL118 Ad, a mutant with the deleted E1B region, were employed. The cells were infected at 20 plaque-forming units, and cell viability was evaluated by the crystal violet method. In the in vivo experiments, 2 x 10(6) cells from the carcinoma cell lines HeLa, A431 and HT29 were injected into nude mice. The tumorigenicity of previously infected cells and after an intratumoral injection of Ad was analyzed. The mice received whole-body gamma-irradiation.

RESULTS

The H5 dL118 mutant produced a marked cytopathic effect in all of the malignant cells, surpassing that of the wt Ad; viability at 72 hours ranged from 11% to 20% for H5 dL118 Ad and from 70% to 93% for the wt Ad with respect to uninfected controls. In the in vivo experiments, a total inhibition of tumorigenicity was detected when cells were infected prior to injection and a partial and transitory decrease in tumorigenicity was detected when the mutant H5 dL118 was injected intratumorally. gamma-irradiation enhanced the in vivo antitumor effects.

CONCLUSIONS

These results indicate that infection with completely E1B-deficient Ads induced a marked cytopathic effect on malignant cells that was higher than that seen for wt Ads; in addition, infection with such Ads exerts a tumor suppressor effect in vivo.

Loss of heterozygosity in the region including the BRCA1 gene on 17q in colon cancer

Colon cancer has been proved to be an excellent model to identify and to study the different genetic alterations taking part in its development. BRCA1, a susceptibility gene for breast cancer, has been identified. Evidence of a significant risk for colon cancer in BRCA1-linked families has been reported. We undertook the present study to investigate the possible relation of BRCA1 and other genes on chromosome 17q21 to colon cancer. Eighty-five tumors were examined for loss of heterozygosity at seven microsatellite loci spanning the 17q21 region. Loss of heterozygosity was present in 39 (49%) of the 79 informative cases, with at least one marker. Two loci, D17S855 and D17S579, showed higher rates of allelic loss (16% and 22%, respectively) than the remaining markers. Tumors on the right side of the colon exhibited allelic loss more frequently than those on the left side. Our data suggest that BRCA1 and other genes in the 17q21 region may play an important role in the development of colon cancer.

In vivo antitumor effect of retrovirus-mediated gene transfer of the adenovirus E1a gene

The adenovirus E1a gene has been shown to be associated with high sensitivity to DNA-damaging agents and a decrease in the tumorigenicity of some human malignant cell lines. We have analyzed the tumorigenicity of the murine epidermoid carcinoma cell lines MSC11A5 and HaCa4, which have constitutive E1a expression, after the concomitant injection of retrovirus E1a producer cells with the carcinoma cells and even after the intratumoral injection of the E1a producer cells. The level of E1a expression was studied by Western blotting. Tumors induced by carcinoma cell lines expressing E1a showed greater latencies and less tumorigenicity. In the spindle cell carcinomas MSC11A5, E1a gene expression partially blocked tumorigenicity. Similar results were obtained after the concomitant injection of the carcinoma cells and the retrovirus E1a producer cells. Intratumoral injection of retrovirus E1a producer cells was associated with a significant delay of tumorigenicity. By transfection with different E1a mutants Ntd1598, d1922/947, and d1787N, we observed that only the mutant that has complete CR2 domains is associated with the decrease in tumorigenicity. According to these results, we conclude that, at least in these carcinoma cell lines, E1a expression exerts a significant antitumor effect in vivo that is mediated by the CR2 region of E1a gene. We propose that injection of retrovirus E1a producer cells may be a novel therapeutic approach in cancer.

Perspectives in gene therapy

Gene therapy is understood to be both the restitution of genetic alterations caused by mutation or deletion and the control of overexpressed genes. The concept of gene therapy can also encompass molecular strategies to induce cell death in tumor cell by either the so-called "suicided genes" or by certain viral genes that induce a more selective cell death among the transformed cells. The prospect for the clinical application of gene therapy are enormous and, at least theoretically, its utilization can be extended to a number of diseases known to have a genetic basis, and to neoplastic processes. This review summarizes some of the projects that are currently underway involving neoplastic diseases, liver diseases, hematopoietic cells and respiratory tract cells. The results of most of the ongoing protocols are not yet conclusive, and presumibly, their clinical application is still some years away. One of the major limitations is the method of introducing the genetic sequences into the cells and achieving their constitutive expression by the cells. For ethical reasons, this approach should not be done in germ cells, but at the level of the tissue or cells most closely involved in the development of each gene-based disease. The methods employed in gene therapy are discussed, focusing on those mediated by the application of viral vectors, as well as those requiring the use of liposomes and others.

Lack of correlation between p53 protein level and sensitivity of DNA-damaging agents in keratinocytes carrying adenovirus E1a mutants

p53 tumor suppressor protein is required for efficient execution of apoptosis after DNA-damage in many cell systems. Since the oncogene E1a confers susceptibility to DNA-damaging agents and stabilizes p53 protein, we investigate whether the sensitivity to anticancer drugs of E1a-expressing cells was mediated by binding to a specific set of cellular proteins (p60, p105, p107 and p300) and related to the induction of apoptosis and the level of p53 protein. We studied the effect of cisplatin (CDDP), doxorubicin (DOX) and ionizing radiation (RX) on murine keratinocytes (PAM 212) transfected by the wild type E1a oncogene or several E1a mutants which bind to different subsets of cellular proteins. Keratinocytes transfected with the mutant d1787N (which binds to p60, p105, p107 and p300) showed a lethality in response to CDDP (10 micrograms ml-1) fourfold higher than controls and threefold higher in response to DOX and radiation (5 grays). The sensitivity of keratinocytes carrying the mutant NTd1598 (binding to p105, p107 and p60) to DNA-damaging agents was similar to that of control keratinocytes, while mutant d1922/947 (binding only to p300) were resistant to CDDP and RX but sensitive to DOX. Apoptosis (after 24 h) studied by DNA fragmentation and flow cytometry was only observed in cells carrying the wild type E1a or the mutant d1787N. After treatment with DNA-damaging agents, p53 protein expression increased in all the cell lines and no rE1ation to sensitivity to anticancer agents or induction of apoptosis was observed. From these results, we conclude that cell sensitivity to cisplatin and ionizing radiation induced by the E1a oncogene requires binding to p105, p107 and p300 cellular proteins, while sensitivity to Doxorubicin requires binding only to p300. Interestingly, p53 protein levels were related to the binding to the p300 protein. The high levels of p53 after CDDP and DOX in the mutant d1922/947, which are only sensitive to DOX, suggest that E1a oncogene products may induce sensitivity to DNA-damaging agents by p53-related and unrelated pathways.