Opposing roles for calcineurin and ATF3 in squamous skin cancer

Cyclosporin A promotes tumor angiogenesis in a calcineurin-independent manner by increasing mitochondrial reactive oxygen species

The widely used immunosuppressant cyclosporin A, a potent calcineurin inhibitor, significantly increases the incidence of cancer in organ transplant patients. Calcineurin signaling is an important mediator of VEGF signaling in endothelial cells. Negative regulation of calcineurin by its endogenous inhibitor, Down Syndrome Candidate Region-1 (DSCR1), suppresses tumor growth and angiogenesis, in contrast to the effect observed after long-term cyclosporin A treatment. Despite the significance of calcineurin signaling in endothelial cells, the consequences of cyclosporin A on tumor angiogenesis have not been investigated. Using an in vivo model of skin carcinogenesis, prolonged treatment with cyclosporin A promoted tumor growth and angiogenesis. The addition of cyclosporin A to endothelial cells in vitro increased proliferation and migration in a calcineurin-independent manner and is associated with increased mitochondrial reactive oxygen species (ROS). Co-treatment with antioxidants significantly abrogated cyclosporin A-induced endothelial cell activation. Furthermore, mice treated with antioxidants were protected against cyclosporin A-mediated tumor progression. Taken together, these findings suggest that cyclosporin A affects endothelial cells in a calcineurin-independent manner to potentiate tumor growth by promoting tumor angiogenesis through increasing mitochondrial ROS production. This work identifies a previously undescribed mechanism underlying a significantly adverse off-target effect of cyclosporin A and suggests that co-treatment with antioxidants would inhibit the tumor-promoting effects of cyclosporin A.

IMPLICATIONS

Targeting the proangiogenic effects of cyclosporin A may be useful in the management of transplant-associated cancers.

Non-melanoma skin cancer is reduced after switch of immunosuppression to mTOR-inhibitors in organ transplant recipients

BACKGROUND

Organ transplant recipients are prone to the development of non-melanoma skin cancer. Organ transplant recipients often develop multiple non-melanoma skin cancers and the tumors show an aggressive growth pattern, therefore surgical therapy can be difficult. Switch of the immunosuppressive regimen to mTOR-inhibitors such as everolimus or sirolimus can have an antitumor effect.

PATIENTS AND METHODS

In a monocentric retrospective study we evaluated organ transplant recipients who presented with non-melanoma skin cancer in the years 2008-2010. Experience with patients who were switched to an mTOR-inhibitor due to non-melanoma skin cancer are reported in detail, and recent clinical studies are reviewed.

RESULTS

60 organ transplant recipients with non-melanoma skin cancer were evaluated. Due to the development of multiple non-melanoma skin cancer within a few years, the immunosuppressive regimen was switched to everolimus in 7 patients and to sirolimus in 5 patients. Eight patients were evaluable for the effect of mTOR-inhibitors on the development of non-melanoma skin cancer; 4 patients had to discontinue the medication with mTOR-inhibitors early due to various side effects. In the year before the switch to mTOR-inhibitors, 8 patients developed 16 squamous cell carcinomas, 3 Basal cell carcinomas and 22 cases of Bowen's disease. All tumors were histologically confirmed. In the year after switch of immunosuppression, the rate of squamous cell carcinomas (n = 2) and Bowen's disease (n = 3), but not of basal cell carcinomas (n = 2) was significantly reduced. Moreover, 5 prospective randomized trials recently have demonstrated a reduced number of non-melanoma skin cancers in organ transplant recipients after switch of the immunosuppressive regimen to mTOR-inhibitors.

CONCLUSION

Switch of the immunosuppressive regimen to mTOR-inhibitors should be considered for organ transplant recipients suffering from multiple non-melanoma skin cancers.

Skin cancer in kidney transplant recipients

Morbidity and mortality due to skin cancer is excessively high in renal transplant recipients compared to the general population. This epidemiologic difference is mainly due to the severe immunosuppression that enhances ultraviolet-induced DNA damage and leads to reactivation of potential oncogenic viruses. The most common skin cancer in transplant recipients is squamous cell carcinoma followed by basal cell carcinoma, while in the general population this ratio is reversed. Melanoma and cutaneous lymphoma are relatively rare although they occur more frequently in transplant patients than in the general population. Notably some tumors, such as Kaposi's sarcoma, are seldom encountered in the general population while they are frequently observed in transplant recipients. Local recurrences and visceral spreading are not so uncommon and pose a major issue for quality of life and overall prognosis of these patients. Timely diagnosis is essential and may be challenging, since the accuracy of clinical diagnosis is modest; thus skin biopsy is an essential tool for appropriate management. In this review, we describe the most common types of skin cancer in renal transplant recipients, with a focus on pathogenic issues that account for the different epidemiology and clinical expression of these neoplasms in this population.

Multifactorial ERβ and NOTCH1 control of squamous differentiation and cancer

Downmodulation or loss-of-function mutations of the gene encoding NOTCH1 are associated with dysfunctional squamous cell differentiation and development of squamous cell carcinoma (SCC) in skin and internal organs. While NOTCH1 receptor activation has been well characterized, little is known about how NOTCH1 gene transcription is regulated. Using bioinformatics and functional screening approaches, we identified several regulators of the NOTCH1 gene in keratinocytes, with the transcription factors DLX5 and EGR3 and estrogen receptor β (ERβ) directly controlling its expression in differentiation. DLX5 and ERG3 are required for RNA polymerase II (PolII) recruitment to the NOTCH1 locus, while ERβ controls NOTCH1 transcription through RNA PolII pause release. Expression of several identified NOTCH1 regulators, including ERβ, is frequently compromised in skin, head and neck, and lung SCCs and SCC-derived cell lines. Furthermore, a keratinocyte ERβ-dependent program of gene expression is subverted in SCCs from various body sites, and there are consistent differences in mutation and gene-expression signatures of head and neck and lung SCCs in female versus male patients. Experimentally increased ERβ expression or treatment with ERβ agonists inhibited proliferation of SCC cells and promoted NOTCH1 expression and squamous differentiation both in vitro and in mouse xenotransplants. Our data identify a link between transcriptional control of NOTCH1 expression and the estrogen response in keratinocytes, with implications for differentiation therapy of squamous cancer.

Calcineurin/Nfatc1 signaling links skin stem cell quiescence to hormonal signaling during pregnancy and lactation

In most tissues, the prevailing view is that stem cell (SC) niches are generated by signals from within the nearby tissue environment. Here, we define genetic changes altered in hair follicle (HF) SCs in mice treated with a potent SC activator, cyclosporine A (CSA), which inhibits the phosphatase calcineurin (CN) and the activity of the transcription factor nuclear factor of activated T cells c1 (Nfatc1). We show that CN/Nfatc1 regulates expression of prolactin receptor (Prlr) and that canonical activation of Prlr and its downstream signaling via Jak/Stat5 drives quiescence of HF SCs during pregnancy and lactation, when serum prolactin (Prl) levels are highly elevated. Using Prl injections and genetic/pharmacological loss-of-function experiments in mice, we show that Prl signaling stalls follicular SC activation through its activity in the skin epithelium. Our findings define a unique CN-Nfatc1-Prlr-Stat5 molecular circuitry that promotes persistent SC quiescence in the skin.

Skin cancer in organ transplant recipients: more than the immune system

Organ transplant recipients (OTRs) are at increased risk of developing nonmelanoma skin cancers. This has long been thought to be caused by immunosuppression and viral infection. However, skin cancer risk among individuals with AIDS or iatrogenic immunodeficiency does not approach the levels seen in OTRs, suggesting other factors play a critical role in oncogenesis. In clinical trials of OTRs, switching from calcineurin inhibitors to mammalian target of rapamycin inhibitors consistently led to a significant reduction in the risk of developing new skin cancers. New evidence suggests calcineurin inhibitors interfere with p53 signaling and nucleotide excision repair. These two pathways are associated with nonmelanoma skin cancer, and squamous cell carcinoma in particular. This finding may help explain the predominance of squamous cell carcinoma over basal cell carcinoma in this population. Mammalian target of rapamycin inhibitors do not appear to impact these pathways. Immunosuppression, viral infection, and impaired DNA repair and p53 signaling all interact in OTRs to create a phenotype of extreme risk for nonmelanoma skin cancer.

The activating transcription factor 3 protein suppresses the oncogenic function of mutant p53 proteins

Mutant p53 proteins (mutp53) often acquire oncogenic activities, conferring drug resistance and/or promoting cancer cell migration and invasion. Although it has been well established that such a gain of function is mainly achieved through interaction with transcriptional regulators, thereby modulating cancer-associated gene expression, how the mutp53 function is regulated remains elusive. Here we report that activating transcription factor 3 (ATF3) bound common mutp53 (e.g. R175H and R273H) and, subsequently, suppressed their oncogenic activities. ATF3 repressed mutp53-induced NFKB2 expression and sensitized R175H-expressing cancer cells to cisplatin and etoposide treatments. Moreover, ATF3 appeared to suppress R175H- and R273H-mediated cancer cell migration and invasion as a consequence of preventing the transcription factor p63 from inactivation by mutp53. Accordingly, ATF3 promoted the expression of the metastasis suppressor SHARP1 in mutp53-expressing cells. An ATF3 mutant devoid of the mutp53-binding domain failed to disrupt the mutp53-p63 binding and, thus, lost the activity to suppress mutp53-mediated migration, suggesting that ATF3 binds to mutp53 to suppress its oncogenic function. In line with these results, we found that down-regulation of ATF3 expression correlated with lymph node metastasis in TP53-mutated human lung cancer. We conclude that ATF3 can suppress mutp53 oncogenic function, thereby contributing to tumor suppression in TP53-mutated cancer.

The oncogene ATF3 is potentiated by cyclosporine A and ultraviolet light A

Cutaneous squamous cell carcinoma (SCC) represents the most important cutaneous complication following organ transplantation. It develops mostly on sun-exposed areas. A recent study showed the role of activating transcription factor 3 (ATF3) in SCC development following treatment with calcineurin inhibitors. It has been reported that ATF3, which may act as an oncogene, is under negative calcineurin/nuclear factor of activated T cells (NFAT) control and is upregulated by calcineurin inhibitors. Still, these findings do not fully explain the preferential appearance of SCC on chronically sun-damaged skin. We analyzed the influence of UV radiation on ATF3 expression and its potential role in SCC development. We found that ATF3 is a specifically induced AP1 member in SCC of transplanted patients. Its expression was strongly potentiated by combination of cyclosporine A and UVA treatment. UVA induced ATF3 expression through reactive oxygen species-mediated nuclear factor erythroid 2-related factor 2 (NRF2) activation independently of calcineurin/NFAT inhibition. Activated NRF2 directly binds to ATF3 promoter, thus inducing its expression. These results demonstrate two mechanisms that independently induce and, when combined together, potentiate the expression of ATF3, which may then force SCC development. Taking into account the previously defined role of ATF3 in the SCC development, these findings may provide an explanation and a mechanism for the frequently observed burden on SCCs on sun-exposed areas of the skin in organ transplant recipients treated by calcineurin inhibitors.

No acceleration of UV-induced skin carcinogenesis from evenly spread dietary intake of cyclosporine in contrast to oral bolus dosages

BACKGROUND

Organ transplant recipients using the immunosuppressant cyclosporine have an increased risk for developing nonmelanoma skin cancer. Disparate effects of cyclosporine have, however, been reported on UV-induced skin carcinogenesis in mouse experiments. Therefore, we set out to compare three experimental protocols using mice, with the aim to emulate most closely the increased skin cancer risk in organ transplant recipients.

METHODS

UV carcinogenesis was performed in hairless SKH-1 mice by three protocols: dietary cyclosporine and daily UV exposures, dietary cyclosporine after a period of UV exposures, and bolus dosing cyclosporine by gavage and repeated UV exposures.

RESULTS

Using chronic UV exposure, continuous dietary administration of cyclosporine was shown to inhibit tumor formation. Dietary cyclosporine after a period of UV exposures did not affect ensuing UV carcinogenesis. However, in contrast with dietary cyclosporine, bolus dosages of cyclosporine by gavage, resulting in strongly varying blood levels of cyclosporine, increased tumor development in chronically UV-exposed mice. There was no difference in tumor development between mice UV-irradiated during peak or trough levels of cyclosporine in the blood. Time-averaged levels in these mice were similar to those with cyclosporine in the diet.

CONCLUSIONS

Cyclosporine in bolus doses appears to increase skin cancer development, whereas cyclosporine administration more evenly spread over time does not. Extrapolation to transplant patients suggests that the mode of administrating cyclosporine may be crucial for the increased skin cancer risk and that this risk might be lowered with a more steady release of cyclosporine in the body.

[Phototherapy and carcinogenesis]

Phototherapy successfully uses the short-term effects of ultraviolet light against inflammation and proliferation. For its long-term effects, however, ultraviolet light was recently classified as a carcinogen. The wave spectrum employed in phototherapy has various carcinogenic effects in experimental systems, most notably DNA mutations in keratinocytes. Clinically, PUVA increases the risk for squamous cell carcinoma of the skin, especially after following 350 or more phototherapy sessions over a lifetime. Melanoma and genital skin cancer are not increased by PUVA alone. Previous UV damage, immunosuppression and other systemic treatments increase cutaneous carcinogenesis through PUVA. In contrast, broad-band UVB, narrow-band UVB and UVA1 have not yet been linked to cutaneous carcinogenesis, but will need careful follow-up in larger studies. Phototherapy remains a safe treatment modality, provided that the indication is well-founded, previous exposure and co-carcinogens are considered, and short and dose-intensive treatment protocols are favored, PUVA is chosen as second-line treatment that should not be used for more than a lifetime total of 250-300 phototherapy sessions.

Kaposi sarcoma in an patient with atopic dermatitis treated with ciclosporin

There are four clinical subtypes of Kaposi sarcoma (KS): classic, endemic, epidemic and iatrogenic. The geographical prevalence of the endemic variant matches areas of human herpes virus type 8 (HHV8) seroprevalence. The iatrogenic variant, seen in immunosuppressed patients, can be associated with significant morbidity and mortality. This is the first report of KS described in the context of atopic dermatitis (AD) treated with ciclosporin (CSA). We report a case of KS in an HHV8 seropositive Congolese patient following immunosuppression with CSA for AD. Treatment has been challenging, protracted and associated with significant morbidity. Immunosuppressive therapies are increasingly used for inflammatory dermatological conditions, including AD. This case highlights the importance of HHV8 screening of patients from endemic regions or those with other risk factors. It also highlights the importance of early recognition of a condition associated with significant morbidity and even mortality to facilitate appropriate treatment.

Kaposi sarcoma in an patient with atopic dermatitis treated with ciclosporin

There are four clinical subtypes of Kaposi sarcoma (KS): classic, endemic, epidemic and iatrogenic. The geographical prevalence of the endemic variant matches areas of human herpes virus type 8 (HHV8) seroprevalence. The iatrogenic variant, seen in immunosuppressed patients, can be associated with significant morbidity and mortality. This is the first report of KS described in the context of atopic dermatitis (AD) treated with ciclosporin (CSA). We report a case of KS in an HHV8 seropositive Congolese patient following immunosuppression with CSA for AD. Treatment has been challenging, protracted and associated with significant morbidity. Immunosuppressive therapies are increasingly used for inflammatory dermatological conditions, including AD. This case highlights the importance of HHV8 screening of patients from endemic regions or those with other risk factors. It also highlights the importance of early recognition of a condition associated with significant morbidity and even mortality to facilitate appropriate treatment.

Expression and clinical significance of activating transcription factor 3 in human breast cancer

OBJECTIVE(S)

Breast cancer is the most common type of cancer among women worldwide. This study investigated the expression and clinical significance of activating transcription factor 3 (ATF3) in human breast cancer and its relationship with the clinical outcome of breast cancer. Materials and Methods : ATF3 expressions were detected in 114 primary breast cancer tissues and 114 adjacent normal tissues using immunohistochemistry (IHC) assay. Categorical variables were statistically compared by chi-square or Fisher's exact test. Survival curves were evaluated using the Kaplan-Meier method and comparisons of survival rates were tested using a Log-rank test. Results : IHC analysis showed that the positive expression of ATF3 protein was detected in breast cancer tissue with a positive ratio of 76.3%, and the positive ATF3 expression in adjacent normal breast tissue was 13.2%, which is lower than that in breast cancer tissue samples (P<0.01). Furthermore, ATF3 expression showed significant correlation with TNM stage, invasion, lymph node metastasis and number of metastatic lymph nodes (P=0.038, P=0.029, P=0.026, and P=0.039 respectively), and did not correlate with patients' age and tumor size (P>0.05). A significant difference in overall survival rate was found between the patients with positive expression of ATF3 protein and those with negative expression (P=0.041). Conclusion : Increased ATF3 expression participate in the tumorigenesis, invasion and metastasis of breast cancer, and ATF3 may be useful as a new prognostic indicator for breast cancer patients.

Papillomavirus-associated squamous skin cancers following transplant immunosuppression: one Notch closer to control

The frequent occurrence of cutaneous squamous cell carcinomas (SCCs) containing weakly tumorigenic human papillomaviruses (HPVs) following iatrogenic immunosuppression for organ transplantation remains incompletely understood. Here we address this problem in the light of recent insights into (1) the association of low-risk β-HPVs with skin SCCs in the rare genetic syndromes of epidermodysplasia verruciformis and xeroderma pigmentosum, (2) the frequent recovery of post-transplant tumor control on substituting calcineurin-inhibitory with mTOR-inhibitory immunosuppression, (3) the unexpectedly favorable prognosis of node-positive SCCs containing high-risk α-HPVs originating in the activated immune niche of the oropharynx, (4) the rapid occurrence of HPV-negative SCCs in ultraviolet (UV)-damaged skin of melanoma patients receiving Raf-inhibitory drugs, and (5) the selective ability of β-HPV E6 oncoproteins to inhibit Notch tumor-suppressive signaling in cutaneous and mesenchymal tissues. The crosstalk so implied between oncogenic UV-induced mutations, defective host immunity, and β-HPV-dependent stromal-epithelial signaling suggests that immunosuppressants such as calcineurin inhibitors intensify mitogenic signalling in TP53-mutant keratinocytes while also abrogating immune-dependent Notch-mediated tumor repression. This emerging interplay between solar damage, viral homeostasis and immune control makes it timely to reappraise strategies for managing skin SCCs in transplant patients.

Hairy cell leukemia in kidney transplantation: lesson from a rare disorder

We report here on the diagnosis and successful treatment of a case of hairy cell leukemia (HCL) that arose 15 years after kidney transplantation in a 51-year-old patient. As soon as the diagnosis was made, HCL was treated with 2-CDA, obtaining complete hematological remission. Immunosuppression with the calcineurin inhibitor cyclosporin was maintained, and the graft was preserved. In kidney transplant recipients supported with immunosuppressive drugs, post-transplant lymphoproliferative diseases (PTLDs) are frequent and typically related to immunosuppression via a loss of control of infectious/EBV-related proliferative stimuli. To date, HCL has not been considered among PTLDs. Recently, however, the oncogenic mutation V600E of the BRAF protein kinase has been found to be a hallmark of HCL, and calcineurin inhibitors have been shown to interfere with signaling downstream of V600E BRAF early on by counteracting senescence-associated mechanisms that protect against the oncogenic potential of the mutated kinase. Such a biochemical link between the oncogene-dependent signaling and calcineurin inhibitor activities suggests that HCL in transplanted patients might be a peculiar type of PTLD based on the presence of a specific mutation. This mechanism might also be involved in other neoplasias bearing the same or similar mutations, such as melanoma and non-melanoma skin cancer.

The retinoid-related orphan receptor RORα promotes keratinocyte differentiation via FOXN1

RORα is a retinoid-related orphan nuclear receptor that regulates inflammation, lipid metabolism, and cellular differentiation of several non-epithelial tissues. In spite of its high expression in skin epithelium, its functions in this tissue remain unclear. Using gain- and loss-of-function approaches to alter RORα gene expression in human keratinocytes (HKCs), we have found that this transcription factor functions as a regulator of epidermal differentiation. Among the 4 RORα isoforms, RORα4 is prominently expressed by keratinocytes in a manner that increases with differentiation. In contrast, RORα levels are significantly lower in skin squamous cell carcinoma tumors (SCCs) and cell lines. Increasing the levels of RORα4 in HKCs enhanced the expression of structural proteins associated with early and late differentiation, as well as genes involved in lipid barrier formation. Gene silencing of RORα impaired the ability of keratinocytes to differentiate in an in vivo epidermal cyst model. The pro-differentiation function of RORα is mediated at least in part by FOXN1, a well-known pro-differentiation transcription factor that we establish as a novel direct target of RORα in keratinocytes. Our results point to RORα as a novel node in the keratinocyte differentiation network and further suggest that the identification of RORα ligands may prove useful for treating skin disorders that are associated with abnormal keratinocyte differentiation, including cancer.

SUMOylation of ATF3 alters its transcriptional activity on regulation of TP53 gene

Cyclic AMP-dependent transcription factor-3 (ATF3), a stress sensor, plays an essential role in cells to maintain homeostasis and has diverse functions in cellular survival and death signal pathways. ATF3 is a novel regulator of p53 protein stability and function. The activities of ATF3 are modulated by post-translational modifications (PTMs), such as ubiquitination, but whether it is modified by small ubiquitin-related modifier (SUMO) remains unknown. The aim of this study was to investigate whether ATF3 is post-translationally modified by SUMO proteins and also to elucidate SUMOylation of ATF3 on TP53 gene activity. Here we report that ATF3 is clearly defined as a SUMO target protein both in vitro SUMOylation assay using recombinant proteins and at the cellular levels. Furthermore, ATF3 interacted with UBE2I, the only SUMO E2 enzyme found so far. In addition, PIAS3β (a SUMO E3 ligase) enhanced and SENP2 and SENP7 (two SUMOylation proteases) decreased SUMOylation of ATF3, respectively. Finally, we found that ATF3 is selectively SUMOylated at lysine residue 42 but the SUMOylation does not alter subcellular localization of ATF3. We then characterized the functional role of ATF3 SUMOylation on TP53 gene expression. We found that SUMOylation of ATF3 is required for full repression of TP53 gene. Overall, we provide the first evidence that ATF3 is post-translationally modified by SUMO and SUMOylation of ATF3 plays a functional role in regulation of TP53 gene activity.

In vivo RNAi screen for BMI1 targets identifies TGF-β/BMP-ER stress pathways as key regulators of neural- and malignant glioma-stem cell homeostasis

In mouse and human neural progenitor and glioblastoma "stem-like" cells, we identified key targets of the Polycomb-group protein BMI1 by combining ChIP-seq with in vivo RNAi screening. We discovered that Bmi1 is important in the cellular response to the transforming growth factor-β/bone morphogenetic protein (TGF-β/BMP) and endoplasmic reticulum (ER) stress pathways, in part converging on the Atf3 transcriptional repressor. We show that Atf3 is a tumor-suppressor gene inactivated in human glioblastoma multiforme together with Cbx7 and a few other candidates. Acting downstream of the ER stress and BMP pathways, ATF3 binds to cell-type-specific accessible chromatin preloaded with AP1 and participates in the inhibition of critical oncogenic networks. Our data support the feasibility of combining ChIP-seq and RNAi screens in solid tumors and highlight multiple p16(INK4a)/p19(ARF)-independent functions for Bmi1 in development and cancer.

β-Asarone induces senescence in colorectal cancer cells by inducing lamin B1 expression

Colorectal cancer is a leading cause of cancer mortality with a complex carcinogenesis that includes reduced cellular senescence. Lamin proteins are decreased in senescing cells, and frequently decreased in malignancies. This study identified a new drug candidate for colorectal cancer that appears to target cell senescence via a lamin protein. β-Asarone (1-propenyl-2,4,5-methoxybenzol) is a compound from the traditional medical herb Acorus calamus Linn. This study tested the in vitro and in vivo effects of β-asarone on colorectal cancer cells by testing cell viability using human colorectal cell lines HT29 and SW480 in MTT assays; tumorigenesis using xenografts in nude mice and a mouse model of colorectal cancer; cell senescence using senescence-associated β-galactosidase activity; and expression of cancer and senescence-related proteins, specifically lamins, Oct-1, p53, p21, and p15, by Western blot. β-Asarone appeared to increase expression of lamin B1, p53, p21, but not lamin A/C. β-Asarone regulates p15 expression by regulation of Oct-1 binding. Collectively, the results suggested that β-asarone inhibits colon cancer formation in vivo and in vitro by inducing senescence. Since β-asarone induced lamin B1 expression, a model is proposed in which β-asarone inhibits colorectal cancer by inducing senescence through lamin B1.

ATF3 suppresses metastasis of bladder cancer by regulating gelsolin-mediated remodeling of the actin cytoskeleton

Bladder cancer is associated with high recurrence and mortality rates due to metastasis. The elucidation of metastasis suppressors may offer therapeutic opportunities if their mechanisms of action can be elucidated and tractably exploited. In this study, we investigated the clinical and functional significance of the transcription factor activating transcription factor 3 (ATF3) in bladder cancer metastasis. Gene expression analysis revealed that decreased ATF3 was associated with bladder cancer progression and reduced survival of patients with bladder cancer. Correspondingly, ATF3 overexpression in highly metastatic bladder cancer cells decreased migration in vitro and experimental metastasis in vivo. Conversely, ATF3 silencing increased the migration of bladder cancer cells with limited metastatic capability in the absence of any effect on proliferation. In keeping with their increased motility, metastatic bladder cancer cells had increased numbers of actin filaments. Moreover, ATF3 expression correlated with expression of the actin filament severing protein gelsolin (GSN). Mechanistic studies revealed that ATF3 upregulated GSN, whereas ATF3 silencing reduced GSN levels, concomitant with alterations in the actin cytoskeleton. We identified six ATF3 regulatory elements in the first intron of the GSN gene confirmed by chromatin immunoprecipitation analysis. Critically, GSN expression reversed the metastatic capacity of bladder cancer cells with diminished levels of ATF3. Taken together, our results indicate that ATF3 suppresses metastasis of bladder cancer cells, at least in part through the upregulation of GSN-mediated actin remodeling. These findings suggest ATF3 coupled with GSN as prognostic markers for bladder cancer metastasis.

Targeting B-cell anergy in chronic lymphocytic leukemia

B-cell receptor (BCR) triggering and responsiveness have a crucial role in the survival and expansion of chronic lymphocytic leukemia (CLL) clones. Analysis of in vitro response of CLL cells to BCR triggering allowed the definition of 2 main subsets of patients and lack of signaling capacity was associated with constitutive activation of extracellular-regulated kinases 1/2 (ERK1/2) and nuclear factor of activated T cells c1 (NF-ATc1), consistent with the idea that at least one group of CLL patients derives from the abnormal expansion of anergic B cells. In the present work, we further investigated the anergic subset of CLL (defined as the one with constitutive ERK1/2 phosphorylation) and found that it is characterized by low levels of surface immunoglobulin M and impairment of calcium mobilization after BCR engagement in vitro. Chronic BCR triggering promoted CLL cell survival selectively in phosphorylated ERK1/2 samples and the use of mitogen-activated protein kinase and NF-AT signaling inhibitors specifically induced apoptosis in this group of patients. Apoptosis induction was preceded by an initial phase of anergy reversal consisting in the loss of ERK phosphorylation and NF-AT nuclear translocation and by the restoration of BCR responsiveness, reinforcing the idea that the anergic program favors the survival of leukemic lymphocytes.

Two-year randomized controlled prospective trial converting treatment of stable renal transplant recipients with cutaneous invasive squamous cell carcinomas to sirolimus

PURPOSE

In light of the significant morbidity and mortality of cutaneous invasive squamous cell carcinomas (SCCs) in renal transplant recipients, we investigated whether conversion to sirolimus-based immunosuppression from standard immunosuppression could diminish the recurrence rate of these skin cancers.

PATIENTS AND METHODS

In a 2-year randomized controlled trial, 155 renal transplant recipients with at least one biopsy-confirmed SCC were stratified according to age (< 55 v ≥ 55 years) and number of previous SCCs (one to nine v ≥ 10) and randomly assigned to conversion to sirolimus (n = 74) or continuation of their original immunosuppression (n = 81). Development of a new SCC within 2 years after random assignment was the primary end point.

RESULTS

After 2 years of follow-up, the risk reduction of new SCCs in the multivariable analysis was not significant, with a hazard ratio (HR) of 0.76 (95% CI, 0.48 to 1.2; P = .255), compared with a non-sirolimus-based regimen. After the first year, there was a significant 50% risk reduction, with an HR of 0.50 (95% CI, 0.28 to 0.90; P = .021) for all patients together and an HR of 0.11 (95% CI, 0.01 to 0.94; P = .044) for patients with only one previous SCC. The tumor burden of SCC was reduced during the 2-year follow-up period in those receiving sirolimus (0.82 v 1.38 per year; HR, 0.51; 95% CI, 0.32 to 0.82; P = .006) if adjusted for the number of previous SCCs and age. Twenty-nine patients stopped taking sirolimus because of various adverse events.

CONCLUSION

Conversion to sirolimus-based immunosuppression failed to show a benefit in terms of SCC-free survival at 2 years.

A surveillance model for skin cancer in organ transplant recipients: a 22-year prospective study in an ethnically diverse population

Skin cancer is a frequent complication of organ transplantation. Current guidelines advise specialist skin surveillance but there are limited data on how these should be implemented. This study determines overall burden of cancer and relevant intervals for strategic surveillance in an ethnically diverse transplant population. Prospective data on time to first and subsequent cancers and cumulative burden with respect to defined risk factors were analyzed in a cohort of 1010 patients in a UK center over 22 years. Among 931 individuals transplanted >6 months (mean 10.3 years), 1820 skin cancers occurred in 267 (29%) individuals and were multiple in 66%. Cumulative incidence at 5, 10, 20 and 30 years was 11%, 25%, 54% and 74%, with median time to second, third and fourth cancers of 24, 14.7 and 8.4 months, respectively. Tumors were overwhelmingly squamous and basal cell carcinomas (73% and 24%, respectively). Skin phototype, ultraviolet radiation exposure, age at transplant and duration of transplant were significant risk predictors and were used to construct clinically relevant surveillance intervals. This study provides a comprehensive, prospective analysis of skin cancer morbidity and risk in an ethnically diverse transplant population from which we derive an evidence-based skin cancer surveillance program.

Management of non-melanoma skin cancer in immunocompromised solid organ transplant recipients

The management of non-melanoma skin cancers (NMSCs) in solid organ transplant recipients (OTRs) presents a variety of clinical challenges for physicians. OTRs are at a 65-fold increased risk for developing cutaneous squamous cell carcinomas (SCC), the most common NMSC that develops after transplantation. Risk factors contributing to the development of NMSCs in OTRs include a past medical history of any previous skin cancer, a personal history of significant sun exposure and a fair skin complexion or phototype. Further, greater immunosuppressive medication levels lead to an increased risk of NMSCs. Among immunosuppressants, specific older agents such as azathioprine and cyclosporine may increase the risk of developing NMSCs in contrast to newer agents such as sirolimus. Early skin biopsy and treatment of premalignant and malignant lesions are essential for treating these patients successfully. In this regard, the concept of field cancerization has been instructive in broadening treatments to include entire affected areas rather than individual lesions given that the areas with significant ultraviolet irradiation will continue to develop numerous individual precancerous and cancerous lesions. Field therapy with photodynamic therapy or topical 5-fluorouracil, imiquimod or diclofenac is often used in OTRs according to individual patient tolerability. Prompt excision or Mohs micrographic surgery is the standard of care of primary, uncomplicated squamous cell and basal cell carcinomas. For patients with in-transit or metastatic squamous cell carcinomas, adjuvant radiation, chemotherapy, and staging by sentinel lymph node dissection may be employed. For patients who develop numerous SCC per year, chemoprophylaxis can be effective in limiting the burden of disease. In consultation with the multidisciplinary transplant team, the immunosuppressive regimen can be revised to lower overall immunosuppression or altered to include newer drugs that have decreased oncogenic potential in OTRs. The greatest impact may be made by the prevention of NMSCs through simple, but rigorous, patient education on the benefits of UV protection, periodic self-skin examinations, and regular follow-ups. Accordingly, vitamin D and calcium supplementation should also be incorporated in transplant recipients. Management of OTRs requires patient education, frequent motivation for vigilance, regular follow-up, and interdisciplinary collaboration between transplant surgeons, nephrologists, hepatologists, cardiologists, transplant nurses, dermatologists, oncologists, pharmacists, and other relevant physicians ideally orchestrated by the essential transplant coordinators.

[Immunosuppressive drugs and the development of skin cancer after organ transplantation]

BACKGROUND

Patients with organ transplants have a significantly increased risk of skin cancer, especially squamous cell carcinoma, as a result of long-term treatment with immunosuppressive drugs. This paper provides a brief overview of the assumed underlying mechanisms.

METHOD

The paper builds on relevant articles and studies identified in the course of many years of interest in immunopharmacology and skin cancer after organ transplantation.

RESULTS

Reduced immunological tumour surveillance as a result of chronic immunosuppression has long been assumed to underlie the increased risk of skin cancer after organ transplants. Recent studies indicate that immunosuppressive drugs may also have specific carcinogenic effects. Aziatropine, which inhibits proliferation of lymphocytes, increases oxidative DNA damage caused by UV radiation. Ciclosporin and tacrolimus, which have an immunosuppressive effect by inhibiting calcineurin, promote malignant phenotypes in cell culture and tumour growth in mouse models. Calcineurin has proved to be necessary in order for p53 protein to have a protective effect against skin cancer. A relatively new class of immunosuppressive drugs, mTOR inhibitors, have antineoplastic properties and are associated with less risk of skin cancer. A number of randomised studies are currently in progress to see whether mTOR inhibitors can reduce the risk of skin cancer after organ transplantation.

INTERPRETATION

Immunosuppressive drugs contribute to skin cancer after organ transplantation, either as a result of immunosuppression or through specific carcinogenic mechanisms. Immunosuppressive drugs with antineoplastic properties are now starting to be used.

Cyclosporine A enhances Th2 bias at the maternal-fetal interface in early human pregnancy with aid of the interaction between maternal and fetal cells

Our previous study has demonstrated that cyclosporine A (CsA) administration in vivo induces Th2 bias at the maternal-fetal interface, leading to improved murine pregnancy outcomes. Here, we investigated how CsA treatment in vitro induced Th2 bias at the human maternal-fetal interface in early pregnancy. The cell co-culture in vitro in different combination of component cells at the maternal-fetal interface was established to investigate the regulation of CsA on cytokine production from the interaction of these cells. It was found that interferon (IFN)-γ was produced only by decidual immune cells (DICs), and not by trophoblasts or decidual stromal cells (DSCs); all these cells secreted interleukin (IL)-4, IL-10, and tumor necrosis factor (TNF)-α. Treatment with CsA completely blocked IFN-γ production in DICs and inhibited TNF-α production in all examined cells. CsA increased IL-10 and IL-4 production in trophoblasts co-cultured with DSCs and DICs although CsA treatment did not affect IL-10 or IL-4 production in any of the cells when cultured alone. These results suggest that CsA promotes Th2 bias at the maternal-fetal interface by increasing Th2-type cytokine production in trophoblasts with the aid of DSCs and DICs, while inhibiting Th1-type cytokine production in DICs and TNF-α production in all investigated cells. Our study might be useful in clinical therapeutics for spontaneous pregnancy wastage and other pregnancy complications.

Multifocal epithelial tumors and field cancerization from loss of mesenchymal CSL signaling

It is currently unclear whether tissue changes surrounding multifocal epithelial tumors are a cause or consequence of cancer. Here, we provide evidence that loss of mesenchymal Notch/CSL signaling causes tissue alterations, including stromal atrophy and inflammation, which precede and are potent triggers for epithelial tumors. Mice carrying a mesenchymal-specific deletion of CSL/RBP-Jκ, a key Notch effector, exhibit spontaneous multifocal keratinocyte tumors that develop after dermal atrophy and inflammation. CSL-deficient dermal fibroblasts promote increased tumor cell proliferation through upregulation of c-Jun and c-Fos expression and consequently higher levels of diffusible growth factors, inflammatory cytokines, and matrix-remodeling enzymes. In human skin samples, stromal fields adjacent to multifocal premalignant actinic keratosis lesions exhibit decreased Notch/CSL signaling and associated molecular changes. Importantly, these changes in gene expression are also induced by UVA, a known environmental cause of cutaneous field cancerization and skin cancer.

The calcium/calcineurin pathway promotes hemidesmosome stability through inhibition of β4 integrin phosphorylation

Cell migration depends on cells being able to create and disassemble adhesive contacts. Hemidesmosomes are multiprotein structures that attach epithelia to basal lamina and disassemble during migration and carcinoma invasion. Phosphorylation of the β4 integrin, a hemidesmosome component, induces disassembly. Although kinases involved in β4 phosphorylation have been identified, little is known about phosphatases countering kinase action. Here we report that calcineurin, a serine-threonine protein phosphatase, regulates β4 phosphorylation. Calcineurin inhibitor cyclosporin A (CsA) and calcineurin-siRNA increase β4 phosphorylation, induce hemidesmosome disassembly, and increase migration in HaCat keratinocytes, suggesting that calcineurin negatively regulates β4 phosphorylation. We found no direct dephosphorylation of β4 by calcineurin or association between β4 and calcineurin, suggesting indirect regulation of β4 phosphorylation. We therefore assessed calcineurin influence on MAPK and PKC, known to phosphorylate β4. CsA increased MAPK activity, whereas MAPK inhibitors reduced CsA-induced β4 phosphorylation, suggesting that calcineurin restricts β4 phosphorylation by MAPK. Calcineurin is activated by calcium. Increased [Ca(2+)](i) reduces β4 phosphorylation and stabilizes hemidesmosomes, effects that are reversed by CsA, indicating that calcineurin mediates calcium effects on β4. However, MAPK activation is increased when [Ca(2+)](i) is increased, suggesting that calcineurin activates an additional mechanism that counteracts MAPK-induced β4 phosphorylation. Interestingly, in some squamous cell carcinoma cells, which have reduced hemidesmosomes and increased β4 phosphorylation, an increase in [Ca(2+)](i) using thapsigargin, bradykinin, or acetylcholine can increase hemidesmosomes and reduce β4 phosphorylation in a calcineurin-dependent manner. These findings have implications in calcineurin-inhibitor induced carcinoma, a complication of immunosuppressive therapy.

Deregulation of XPC and CypA by cyclosporin A: an immunosuppression-independent mechanism of skin carcinogenesis

Skin cancer is the most common malignancy in organ transplant recipients, causing serious morbidity and mortality. Preventing and treating skin cancer in these individuals has been extraordinarily challenging. Following organ transplantation, cyclosporin A (CsA) has been used as an effective immunosuppressive to prevent rejection. Therefore immunosuppression has been widely assumed to be the major cause for increased skin carcinogenesis. However, the mechanism of skin carcinogenesis in organ transplant recipients has not been understood to date; specifically, it remains unknown whether these cancers are immunosuppression dependent or independent. Here, using both immunocompromised nude mice which are defective in mature T lymphocytes as an in vivo model and human keratinocytes as an in vitro model, we showed that CsA impairs genomic integrity in the response of keratinocytes to ultra violet B (UVB). Following UVB radiation, CsA inhibited UVB-induced DNA damage repair by suppressing the transcription of the DNA repair factor xeroderma pigmentosum C (XPC). In addition, CsA compromised the UVB-induced checkpoint function by upregulating the molecular chaperone protein cyclophilin A (CypA). XPC mRNA levels were lower, whereas CypA mRNA and protein levels were higher in human skin cancers than in normal skin. CsA-induced phosphoinositide 3-kinase(PI3K)/AKT activation was required for both XPC suppression and CypA upregulation. Blocking UVB damage or inhibiting the PI3K/AKT pathway prevented CsA-sensitized skin tumorigenesis. Our findings identified deregulation of XPC and CypA as key targets of CsA, and UVB damage and PI3K/AKT activation as two principal drivers for CsA-sensitized skin tumorigenesis, further supporting an immunosuppression-independent mechanism of CsA action on skin tumorigenesis.

Sirolimus and secondary skin-cancer prevention in kidney transplantation

BACKGROUND

Transplant recipients in whom cutaneous squamous-cell carcinomas develop are at high risk for multiple subsequent skin cancers. Whether sirolimus is useful in the prevention of secondary skin cancer has not been assessed.

METHODS

In this multicenter trial, we randomly assigned transplant recipients who were taking calcineurin inhibitors and had at least one cutaneous squamous-cell carcinoma either to receive sirolimus as a substitute for calcineurin inhibitors (in 64 patients) or to maintain their initial treatment (in 56). The primary end point was survival free of squamous-cell carcinoma at 2 years. Secondary end points included the time until the onset of new squamous-cell carcinomas, occurrence of other skin tumors, graft function, and problems with sirolimus.

RESULTS

Survival free of cutaneous squamous-cell carcinoma was significantly longer in the sirolimus group than in the calcineurin-inhibitor group. Overall, new squamous-cell carcinomas developed in 14 patients (22%) in the sirolimus group (6 after withdrawal of sirolimus) and in 22 (39%) in the calcineurin-inhibitor group (median time until onset, 15 vs. 7 months; P=0.02), with a relative risk in the sirolimus group of 0.56 (95% confidence interval, 0.32 to 0.98). There were 60 serious adverse events in the sirolimus group, as compared with 14 such events in the calcineurin-inhibitor group (average, 0.938 vs. 0.250). There were twice as many serious adverse events in patients who had been converted to sirolimus with rapid protocols as in those with progressive protocols. In the sirolimus group, 23% of patients discontinued the drug because of adverse events. Graft function remained stable in the two study groups.

CONCLUSIONS

Switching from calcineurin inhibitors to sirolimus had an antitumoral effect among kidney-transplant recipients with previous squamous-cell carcinoma. These observations may have implications concerning immunosuppressive treatment of patients with cutaneous squamous-cell carcinomas. (Funded by Hospices Civils de Lyon and others; TUMORAPA ClinicalTrials.gov number, NCT00133887.).

Combined inhibition of p38 and Akt signaling pathways abrogates cyclosporine A-mediated pathogenesis of aggressive skin SCCs

Non-melanoma skin cancers (NMSCs) are the most common neoplasm in organ transplant recipients (OTRs). These cancers are more invasive and metastatic as compared to those developed in normal cohorts. Previously, we have shown that immunosuppressive drug, cyclosporine A (CsA) directly alters tumor phenotype of cutaneous squamous cell carcinomas (SCCs) by activating TGF-β and TAK1/TAB1 signaling pathways. Here, we identified novel molecular targets for the therapeutic intervention of these SCCs. We observed that combined blockade of Akt and p38 kinases-dependent signaling pathways in CsA-promoted human epidermoid carcinoma A431 xenograft tumors abrogated their growth by more than 90%. This diminution in tumor growth was accompanied by a significant decrease in proliferation and an increase in apoptosis. The residual tumors following the combined treatment with Akt inhibitor triciribine and p38 inhibitors SB-203580 showed significantly diminished expression of phosphorylated Akt and p38 and these tumors were less invasive and highly differentiated. Diminished tumor invasiveness was associated with the reduced epithelial-mesenchymal transition as ascertained by the enhanced E-cadherin and reduced vimentin and N-cadherin expression. Consistently, these tumors also manifested reduced MMP-2/9. The decreased p-Akt expression was accompanied by a significant reduction in p-mTOR. These data provide first important combinatorial pharmacological approach to block the pathogenesis of CsA-induced highly aggressive cutaneous neoplasm in OTRs.

MiR-1246: a new link of the p53 family with cancer and Down syndrome

Since the discovery of miRNAs, a number of miRNAs have been identified as p53's transcriptional targets. Most of them are involved in regulation of the known p53 functions, such as cell cycle, apoptosis and senescence. Our recent study revealed miR-1246 as a novel target of p53 and its analogs p63 and p73 to suppress the expression of DYRK1A and consequently activate NFAT, both of which are associated with Down syndrome and possibly with tumorigenesis. This finding suggests that miR-1246 might serve as a likely link of the p53 family with Down syndrome. Here, we provide some prospective views on the potential role of the p53 family in Down syndrome via miR-1246 and propose a new p53-miR-1246-DYRK1A-NFAT pathway in cancer.

Differentiation-induced skin cancer suppression by FOS, p53, and TACE/ADAM17

Squamous cell carcinomas (SCCs) are heterogeneous and aggressive skin tumors for which innovative, targeted therapies are needed. Here, we identify a p53/TACE pathway that is negatively regulated by FOS and show that the FOS/p53/TACE axis suppresses SCC by inducing differentiation. We found that epidermal Fos deletion in mouse tumor models or pharmacological FOS/AP-1 inhibition in human SCC cell lines induced p53 expression. Epidermal cell differentiation and skin tumor suppression were caused by a p53-dependent transcriptional activation of the metalloprotease TACE/ADAM17 (TNF-α-converting enzyme), a previously unknown p53 target gene that was required for NOTCH1 activation. Although half of cutaneous human SCCs display p53-inactivating mutations, restoring p53/TACE activity in mouse and human skin SCCs induced tumor cell differentiation independently of the p53 status. We propose FOS/AP-1 inhibition or p53/TACE reactivating strategies as differentiation-inducing therapies for SCCs.

Lipocalin 2, the TNF-like receptor TWEAKR and its ligand TWEAK act downstream of NFAT1 to regulate breast cancer cell invasion

NFAT1 is a transcription factor that elicits breast carcinoma cells to become invasive, thus contributing to metastasis. The molecular mechanisms by which NFAT1 operates in this respect are still poorly known. Here, we report that NFAT1 increases lipocalin 2 (LCN2) mRNA and protein expression by binding to specific sites in the LCN2 gene promoter region. We show that the LCN2 protein is required downstream of NFAT1 to increase breast cancer cell invasion. We demonstrate that the NFAT1-LCN2 axis is sufficient to regulate expression of the TNF-like receptor TWEAKR at the RNA level and of its ligand, TWEAK, at the protein level. We show, however, that TWEAKR mediates an anti-invasive effect in breast cancer cells whereas, depending on LCN2 expression, TWEAK has either anti- or pro-invasive capacities. Thus, we identify LCN2 and TWEAKR-TWEAK as crucial downstream effectors of NFAT1 that regulate breast cancer cell motility and invasive capacity.

The utility of ATF3 in distinguishing cutaneous squamous cell carcinoma among other cutaneous epithelial neoplasms

The histopathologic distinction between benign and malignant cutaneous keratinocytic proliferations can pose a difficult diagnostic challenge - often with important clinical implications. Activating transcription factor 3 (ATF3) has emerged as a potential biomarker which may aid in the segregation of these lesions, and we hypothesize that ATF3 expression may be a specific marker of cutaneous squamous cell carcinoma (SCC). Using immunohistochemistry, we characterized ATF3 expression in a series of 126 cutaneous epithelial proliferations, including SCC (n = 27), basal cell carcinomas (BCC, n = 59), seborrheic keratoses with atypia (SK, n = 16), hyperplastic actinic keratoses (AK, n = 12) and prurigo nodularis cases (PN, n = 12). We showed strong, nuclear and/or nucleolar expression of ATF3 in a statistically significant number of cases of SCC compared to BCC, SK and PN. We conclude that ATF3 expression is a surrogate of malignancy (or pre-malignancy) in keratinocytic epithelial proliferations and thus helps distinguish SCC from other cutaneous epithelial neoplasms.

Effects of arsenite and UVA-1 radiation on calcineurin signaling

Calcineurin is a Ca(2+)-dependent serine/threonine phosphatase and the target of the immunosuppressive drugs cyclosporin and tacrolimus, which are used in transplant recipients to prevent rejection. Unfortunately, the therapeutic use of this drugs is complicated by a high incidence of skin malignancy, which has set off a number of studies into the role of calcineurin signaling in skin, particularly with respect to cell cycle control and DNA repair. Both UVA1 radiation and arsenic species are known to promote skin cancer development via production of reactive oxygen species. In light of the well-documented sensitivity of calcineurin to oxidative stress, we examined and compared the effects of UVA1 and arsenite on calcineurin signaling. In this paper, we show that physiologically relevant doses of UVA1 radiation and low micromolar concentrations of arsenite strongly inhibit calcineurin phosphatase activity in Jurkat and skin cells and decrease NFAT nuclear translocation in Jurkat cells. The effects on calcineurin signaling could be partly prevented by inhibition of NADPH oxidase in Jurkat cells or increased dismutation of superoxide in Jurkat and skin cells. In addition, both UVA1 and arsenite decreased NF-κB activity, although at lower concentrations, arsenite enhanced NF-κB activity. These data indicate that UVA1 and arsenite affect a signal transduction route of growingly acknowledged importance in skin and that calcineurin may serve as a potential link between ROS exposure and impaired tumor suppression.

Therapeutic options to decrease actinic keratosis and squamous cell carcinoma incidence and progression in solid organ transplant recipients: a practical approach

BACKGROUND

Solid organ transplant recipients (SOTRs) have a 50 to 250 times greater risk of squamous cell carcinoma (SCC) than the general population and experience higher rates of invasive and metastatic disease. These greater risks are a product of the tumorigenic effects of their immunosuppressive medications. As the number of transplantations and the life expectancy of SOTRs increase, SCCs are becoming a major source of morbidity and mortality.

OBJECTIVE

To present a practical approach for busy practicing clinicians to the care of SOTRs who are developing SCCs. Topics include assessment and treatment of new and neglected SOTRs; the dermatologist's role with the transplantation team; and practical considerations in the choice of topical agents, systemic agents, and immunosuppressive therapy manipulation.

METHODS AND MATERIALS

An extensive literature search of the understanding of SCC pathophysiology and treatment in SOTRs was conducted.

RESULTS

Presented here is a logical, concise guide to the care of SOTRs who are developing actinic keratoses and SCCs.

CONCLUSION

Proper assessment of patients, understanding therapeutic alternatives and their application, and early institution of preventative and adjuvant therapies can help to decrease skin cancer-related morbidity and mortality in SOTRs.

Gene expression changes in melanoma metastases in response to high-dose chemotherapy during isolated limb perfusion

Despite recent advances in melanoma therapy, disseminated melanoma still lacks effective treatment, and recurrence of the tumor frequently occurs, even after high-dose chemotherapy. The mechanisms responsible for this chemoresistance or for the formation of new relapses remain poorly understood. Using a human 'model', in which the isolated limb is perfused with high doses of the chemotherapeutic melphalan (ILP), we identified a five-gene set (ATF3, CYR61, IER5, IL6, and PTGS2) of stress-induced genes that was consistently upregulated after ILP in all in-transit metastatic melanoma samples as well as in three melphalan-treated melanoma cell lines. Early post-ILP relapses retained these elevated expressions, whereas the expression of these genes returned to their original levels in late post-ILP recurrences. In addition, we identified upregulation of these genes in the A375 cell line's side population (SP) and melanospheres, established methods to enrich for candidate cancer stem cells (CSCs), which are considered chemoresistant and tumorigenic, and thus proposed to be responsible for tumor relapse. Our data identify an immediate and short-term upregulation of early stress-responsive genes that are potentially linked to chemoresistance and CSCs.

Cutaneous side effects of inhibitors of the RAS/RAF/MEK/ERK signalling pathway and their management

Mutations in genes encoding for proteins along the RAS-RAF-MEK-ERK pathway have been detected in a variety of tumor entities, including malignant melanoma, thyroid, colonic and ovarian carcinomas, and some sarcomas. Thus, a number of inhibitors of this pathway have been developed, whose antitumor potential is currently being assessed in different clinical trials. Up to now one drug of this category (vemurafenib) has been approved by the FDA and the European Commission for late-stage melanoma. Although these new targeted anticancer therapies are generally considered to be safe and well tolerated, certain toxicities have been attributed to them, with cutaneous side effects being perhaps the most frequent amongst them. Based on results of clinical trials and on case series, a distinct profile of cutaneous toxicity has been observed, which is similar to that of EGFR and multikinase inhibitors. As exanthema, palmar-plantar erythrodysesthesia syndrome, hyperkeratosis, xerosis, pruritus, photosensitivity, and paronychia, can be controlled in most cases with common conservative modalities, special attention should be given to the early detection of epithelial skin tumors (mainly keratoakanthomas) that can be induced during therapy with these agents. This report reviews all current published data on cutaneous side effects of RAS-RAF-MEK-ERK pathway inhibitors, and attempts to provide the clinician with clear hints for their management.

Molecular Diagnostics of Calcineurin-Related Pathologies

BACKGROUND

The Ca2+-dependent protein phosphatase enzyme calcineurin (Cn) (protein phosphatase 3) is best known for its role as director of the adaptive immune response. One of its principal substrates is the nuclear factor of activated T cells (NFAT), which translocates to the nucleus after dephosphorylation to mediate gene transcription. Drugs targeting Cn (the Cn inhibitors tacrolimus and cyclosporin A) have revolutionized posttransplantation therapy in allograft recipients by considerably reducing rejection rates.

CONTENT

Owing primarily to intensive study of the side effects of the Cn inhibitors, the unique importance of Cn and Cn/NFAT signaling in the normal physiological processes of many other cell and tissue types is becoming more evident. During the last decade, it has become clear that an extensive and diverse array of clinical conditions can be traced back, at least in part, to a disturbed Cn-signaling axis. Hence, both diagnostics and therapeutic monitoring could benefit from a technique that conveniently reads out Cn/NFAT operative status.

SUMMARY

This review outlines the current knowledge on the pathologic conditions that have calcineurin as a common denominator and reports on the progress that has been made toward successfully applying Cn and Cn/NFAT activity markers in molecular diagnostics.

From keratinocyte to cancer: the pathogenesis and modeling of cutaneous squamous cell carcinoma

Cutaneous squamous cell carcinoma (cSCC) is the second most common human cancer with over 250,000 new cases annually in the US and is second in incidence only to basal cell carcinoma. cSCC typically manifests as a spectrum of progressively advanced malignancies, ranging from a precursor actinic keratosis (AK) to squamous cell carcinoma (SCC) in situ (SCCIS), invasive cSCC, and finally metastatic SCC. In this Review we discuss clinical and molecular parameters used to define this range of cutaneous neoplasia and integrate these with the multiple experimental approaches used to study this disease. Insights gained from modeling cSCCs have suggested innovative therapeutic targets for treating these lesions.

Calcineurin subunit B upregulates β-interferon production by phosphorylation of interferon regulatory factor 3 via Toll-like receptor 4

Toll-like receptors (TLRs) function as pattern-reorganization receptors in mammals and play an essential role in innate immunity. After recognizing certain ligands, TLRs activate a cascade of signal pathways to establish a guard environment. For the first time, we report that in vitro treatment with recombinant calcineurin subunit B (CNB) upregulated several TLR-related genes. Calcineurin subunit B interacted with the ectodomain of TLR4 in vitro. On further investigation, phosphorylation of interferon regulatory factor 3 and degradation of IκB-α were observed by CNB stimulation. In addition to pro-inflammatory cytokines, transcription and production of β-interferon were also enhanced after CNB stimulation. Thus, CNB could be further explored as a cancer and virus immunotherapy drug.

Reversal of UVA skin photosensitivity and DNA damage in kidney transplant recipients by replacing azathioprine

Azathioprine is associated with enhanced skin photosensitivity to ultraviolet A (UVA) and leads to incorporation of 6-thioguanine (6-TG) into DNA of dividing cells. Unlike canonical DNA, 6-TG DNA is damaged by UVA, which comprises more than 90% of the ultraviolet reaching earth. Skin photosensitivity to UVA and UVB was measured in 48 kidney transplant patients immunosuppressed either by azathioprine (n = 32) or mycophenolate (n = 16). In 23 patients, azathioprine was subsequently replaced by mycophenolate and skin photosensitivity, DNA 6-TG content in peripheral blood mononuclear cells, and susceptibility to UVA-induced DNA damage were monitored for up to 2 years. The mean minimal erythema dose to UVA on azathioprine was twofold lower than on mycophenolate. Three months after replacing azathioprine by mycophenolate mofetil, the minimal erythema dose to UVA had increased from 15 to 25 J/cm(2) (p < 0.001) accompanied by reduced DNA 6-TG content. P53 protein expression in irradiated skin indicated reduced susceptibility to UVA-induced DNA damage. 6-TG DNA in peripheral blood mononuclear cells remained measurable for over 2 years. Replacing azathioprine selectively reduced the skin photosensitivity to UVA, attenuated UVA-induced skin DNA damage, and is likely based on incorporated 6-TG in DNA.