Intercellular adhesion molecule 1 (ICAM-1) and bcl-2 are differentially expressed in early evolving malignant melanoma

Immunohistochemical Study of 49 Cutaneous Melanomas: P53, PCNA, Bcl-2 Expression and Multidrug Resistance

Aims and Background

Thickness and level of invasion are the main morphological elements for an approximate but not sufficiently sensitive prognostic evaluation of cutaneous melanomas. By using immunohistochemical methods it is possible to detect biological markers related to prognosis. We have studied p53, PCNA, Bcl-2 and P-gp expression in 49 primary cutaneous melanomas.

Materials

We used the immunophosphatase APAAP immunohistochemical method. The percentage of labeled cells (according to four classes of positivity: <5%; 5-25%; 25-50%; >50%) and the localization of immunoreactivity were expressed for each marker. Statistical analysis was performed to determine the correlations between markers and level or thickness of melanomas.

Results

We found a good correlation between p53 expression and melanoma thickness (P <0.005), PCNA and P-gp expression. No relationship was observed between Bcl-2 expression and the different variables considered or other markers.

Conclusions

Our data seem to indicate an unfavorable prognostic role of higher nuclear p53 expression. However, we believe that our results need to be integrated with patients’ clinical follow-up and with the study of the expression of these markers in benign melanocytic lesions to gain more accurate information about their prognostic significance.

Kaposi's Sarcoma-Associated Herpesvirus Subversion of the Anti-Inflammatory Response in Human Skin Cells Reveals Correlates of Latency and Disease Pathogenesis

KSHV is the etiologic agent for Kaposi's sarcoma (KS), a neoplasm that manifests most aggressively as multifocal lesions on parts of human skin with a propensity for inflammatory reactivity. However, mechanisms that control evolution of KS from a benign hyperplasia to the histologically complex cutaneous lesion remain unknown. In this study, we found that KSHV induces proteomic and morphological changes in melanocytes and melanoma-derived cell lines, accompanied by deregulation of the endogenous anti-inflammatory responses anchored by the MC1-R/α-MSH signaling axis. We also identified two skin-derived cell lines that displayed differences in ability to support long-term KSHV infection and mapped this dichotomy to differences in (a) NF-κB activation status, (b) processing and expression of KSHV latency-associated nuclear antigen isoforms putatively associated with the viral lytic cycle, and (c) susceptibility to virus-induced changes in expression of key anti-inflammatory response genes that antagonize NF-κB, including MC1-R, POMC, TRP-1, and xCT. Viral subversion of molecules that control the balance between latency and lytic replication represents a novel correlate of KSHV pathogenesis and tropism in skin and underscores the potential benefit of harnessing the endogenous anti-inflammatory processes as a therapeutic option for attenuating cutaneous KS and other proinflammatory outcomes of KSHV infection in high-risk individuals.

Born to be alive: a role for the BCL-2 family in melanoma tumor cell survival, apoptosis, and treatment

The global incidence of melanoma has dramatically increased during the recent decades, yet the advancement of primary and adjuvant therapies has not kept a similar pace. The development of melanoma is often centered on cellular signaling that hyper-activates survival pathways, while inducing a concomitant blockade to cell death. Aberrations in cell death signaling not only promote tumor survival and enhanced metastatic potential, but also create resistance to anti-tumor strategies. Chemotherapeutic agents target melanoma tumor cells by inducing a form of cell death called apoptosis, which is governed by the BCL-2 family of proteins. The BCL-2 family is comprised of anti-apoptotic proteins (e.g., BCL-2, BCL-xL, and MCL-1) and pro-apoptotic proteins (e.g., BAK, BAX, and BIM), and their coordinated regulation and function are essential for optimal responses to chemotherapeutics. Here we will discuss what is currently known about the mechanisms of BCL-2 family function with a focus on the signaling pathways that maintain melanoma tumor cell survival. Importantly, we will critically evaluate the literature regarding how chemotherapeutic strategies directly impact on BCL-2 family function and offer several suggestions for future regimens to target melanoma and enhance patient survival.

Expression of adhesion molecules and ligands for activating and costimulatory receptors involved in cell-mediated cytotoxicity in a large panel of human melanoma cell lines

Knowledge of the interactions between MHC-unrestricted cytotoxic effector cells and solid tumour cells is essential for introducing more effective NK cell-based immunotherapy protocols into clinical practise. Here, to begin to obtain an overview of the possible universe of molecules that could be involved in the interactions between immune effector cells and melanoma, we analyse the surface expression of adhesion and costimulatory molecules and of ligands for NK-activating receptors on a large panel of cell lines from the "European Searchable Tumour Cell Line and Data Bank" (ESTDAB, http://www.ebi.ac.uk/ipd/estdab/ ) and discuss their potential role in the immune response against this tumour. We show that most melanoma cell lines express not only adhesion molecules that are likely to favour their interaction with cells of the immune system, but also their interaction with endothelial cells potentially increasing their invasiveness and metastatic capacity. A high percentage of melanoma cell lines also express ligands for the NK-activating receptor NKG2D; whereas, the majority express MICA/B molecules, ULBP expression, however, was rarely found. In addition to these molecules, we also found that CD155 (poliovirus receptor, PVR) is expressed by the majority of melanoma cell lines, whereas CD112 (Nectin-2) expression was rare. These molecules are DNAM-1 ligands, a costimulatory molecule involved in NK cell-mediated cytotoxicity and cytokine production that also mediates costimulatory signals for triggering naïve T cell differentiation. The phenotypical characterisation of adhesion molecules and ligands for receptors involved in cell cytotoxicity on a large series of melanoma cell lines will contribute to the identification of markers useful for the development of new immunotherapy strategies.

Bcl-2 expression is not associated with survival in metastatic cutaneous melanoma: a historical cohort study

Background

Programmed cell death (apoptosis) has been implicated in tumor development and may affect the metastatic potential of tumor cells. The role of bcl-2, a proto-oncogene that inhibits apoptosis, has been studied in several malignancies, including cutaneous melanoma (CM). The purpose of this study was to evaluate the immunohistochemical expression of bcl-2 in 35 regional lymph node, 28 subcutaneous and 17 visceral CM metastases, correlating the findings with patient survival.

Methods

In a historical cohort study patient survival was correlated with the expression of bcl-2 in regional lymph node, subcutaneous and visceral metastases of CM. Eighty slides containing surgical specimens from 50 patients diagnosed with stage III and IV CM, 28 male (56%) and 22 female (44%), were analyzed. Mean age at diagnosis was 43 years (16–74 years; median = 42 years). Mean Breslow depth was 5.01 mm (0.4–27.5 mm). The slides were submitted to immunohistochemical reaction using anti-bcl-2 monoclonal antibody and classified according to the degree of staining (< 5%; 5 to 50%; or > 50% of tumor cells stained). The relationship between bcl-2 protein expression and survival for each type of metastasis, gender and age at initial diagnosis was analyzed.

Results

Mean overall survival was 33.9 months after the diagnosis of the initial metastatic lesion (range: 0 to 131 months). Twenty-four out of 50 patients (48%) had died from CM by the end of the study period. bcl-2 expression was detected in 74.3, 85.7 and 82.4% of lymph node, subcutaneous and visceral metastases, respectively. After univariate and multivariate analyses, no correlation was found between positive bcl-2 expression and overall survival for the types of metastases evaluated.

Conclusion

The immunohistochemical expression of bcl-2 in metastasis alone is not a prognostic marker for CM.

Mcl-1, Bcl-XL and Stat3 expression are associated with progression of melanoma whereas Bcl-2, AP-2 and MITF levels decrease during progression of melanoma

Members of the Bcl-2 family of antiapoptotic proteins (Bcl-2, Bcl-XL and Mcl-1) are key regulators of apoptosis. The purpose of the present study was to examine and better define the role of Bcl-2, Bcl-XL and Mcl-1 in the progression of melanoma. Immunohistochemical staining for Bcl-2, Bcl-XL and Mcl-1 was performed on paraffin sections of 100 cases of benign nevi, primary melanoma and metastatic melanoma. Expression was correlated with histopathologic features, clinical progress and expression of transcription factors (AP-2, MITF and p-Stat3). Bcl-2 was expressed in 100% of benign nevi and thin melanoma (<or=1.0 mm) but was less in thick melanoma (>1.0 mm) (88%), subcutaneous (62%) and lymph node metastases (35%). In contrast, Bcl-XL and Mcl-1 were expressed at lower levels in nevi and thin melanoma compared to Bcl-2 but their expression was much higher in thick melanoma and in subcutaneous and lymph node metastases (P<0.0001). Bcl-2 expression was negatively associated with tumor thickness (P<0.05) but Bcl-XL expression increased with increasing tumor thickness (P<0.05) and dermal tumor mitotic rate (P<0.05). Similarly Mcl-1 expression increased with increasing tumor thickness (P<0.09) and dermal tumor mitotic rate (P<0.17). Bcl-2 expression was positively correlated with expression of the transcription factors microphthalmia transcription factor (MITF) and nuclear AP-2 whereas Bcl-XL (and Mcl-1) expression were positively correlated with p-Stat3. This study is the first to show a clear dissociation between changes in Bcl-2 expression (downregulation) and Bcl-XL, Mcl-1 expression (upregulation) during progression of melanoma. The results were also consistent with a role for AP-2 and MITF in regulation of Bcl-2 and pStat3 in regulation of Bcl-XL. These findings have important implications for the development of treatments targeting antiapoptotic proteins in patients with melanoma.

Proliferation, apoptosis, and survivin expression in keratinocytic neoplasms and hyperplasias

The dysregulation of apoptosis occurs in many cutaneous disease states. Several apoptosis inhibitors have been shown elevated in neoplasms and in some inflammatory conditions, but their relation to proliferative and apoptotic states has not been defined. We examined the expression of the apoptosis inhibitor survivin in a panel of keratinocytic neoplasms and hyperproliferative skin lesions using both immunohistochemistry and a newly developed in situ hybridization technique. Proliferation and apoptotic indices were also assessed by immunohistochemical staining for proliferating cell nuclear antigen and TUNEL, respectively. We found the highest rate of proliferation in verrucae and psoriasis followed by actinic keratosis, squamous and basal cell carcinoma, lichen simplex chronicus, and seborrheic keratosis; all were significantly (P < 0.05) higher than normal skin. Apoptotic rate was increased in squamous (P = 0.05) and basal cell carcinoma (P = 0.03), but not significantly different from normal skin in the other lesions tested. Survivin expression was seen in most neoplasms and hyperproliferative lesions, but not normal skin. Survivin expression was often restricted to the upper third of the epidermis in psoriasis and lichen simplex chronicus, whereas all the other lesions stained diffusely. Survivin expression appears to be a consistent feature of keratinocytic neoplasms and hyperproliferative lesions and may contribute to the formation of epidermal hyperplasia seen in all of these disease states.

Prognostic signs in melanoma: state of the art

Prognoses for melanoma patients are currently based on statistically confirmed parameters, above all the Breslow thickness and number of lymph node and/or distant metastases. However, metastases can develop even with "thin" melanomas (< 0.7 mm), while survival has been recorded in patients with tumours classified as "thick" (> 4 mm). This review of the literature examines the most recent advances in prognostic markers for melanoma (serological, immunohistochemical, histological, genetic and surgical). These markers offer interesting possibilities in terms of diagnostic certainty, identification of early growth phases and estimation of the tumour's potential for progression and metastasis. It is reasonable to assume that their combined use can provide useful information for formulating prognoses that are not only statistically valid but also individualized.

The role of Bcl-2 family members in the progression of cutaneous melanoma

The overwhelming problem of cutaneous melanoma is chemoresistance. Subversion of the biochemical changes that lead to chemoresistance intersects the apoptosis pathways. The mitochondrion has been a focal point of this intersection for the development of therapeutic strategies aimed at reducing the progression of melanoma. The Bcl-2 family of apoptotic regulators is arguably the most pivotal component to this mitochondrial response. The shear number of studies conducted on the relationship between melanoma and Bcl-2 members prompted us to evaluate the literature available and discern some rational utility of the data. We have found that there are striking inconsistencies for the expression of Bcl-2 family proteins with melanoma progression, particularly for Bcl-2. Roughly one-third of the data suggests an increase in Bcl-2 expression with advancing melanoma, while another third suggests a decrease. Furthermore, the remaining third found on the whole, a detectable level of Bcl-2 in all tissues of melanocytic origin. These discrepancies are difficult to rectify in light of the apparent success of recent clinical trials utilizing Bcl-2 antisense strategies. The general consensus in the literature is that pro-apoptotic Bax is decreased with melanoma progression while anti-apoptotic Bcl-xL and Mcl-1 appear to increase with progression. We suggest that the biochemical techniques being used for analysis present too great of a heterogeneity, which could be mitigated with more standard procedures and reagents. Finally the utility of 'multi-specific' antisense tactics could be a more effective way of targeting advanced melanoma disease.

Apoptosis regulators and responses in human melanocytic and keratinocytic cells

Apoptosis in keratinocytes is required for epidermal turnover, stratum corneum formation, and removal of ultraviolet-damaged premalignant cells. Its role in melanocyte homeostasis and transformation, on the other hand, has not been defined, although apoptosis resistance is a commonly recognized feature of melanoma. We examined the expression of apoptosis regulators in melanocytes, keratinocytes, melanoma, and HaCat cells. Melanocytic cells expressed relatively high levels of Bcl-2, Bcl-X(L), Mcl-1, C-IAP-1, C-IAP-2, XIAP, Livin, and Apaf-1. The only apoptotic regulator that was differentially expressed in melanoma cells and not melanocytes was Survivin, whereas Bax was expressed in melanocytes but not in most melanoma lines. Keratinocytic cells, on the other hand, expressed high levels of FLIP and were relatively deficient in Bcl-2 family proteins. Levels of p53 were highest in HaCat cells and some of the melanoma lines, and barely detectable in melanocytes and keratinocytes. Next, susceptibility of these cells types to apoptosis induced by ultraviolet B, the tyrosine analog 4-tert-butylphenol, and cytotoxic drugs was examined. Melanocytes were relatively resistant to ultraviolet B, whereas keratinocytes were unresponsive to 4-tert-butylphenol. Melanocytes and keratinocytes were generally less susceptible than melanoma lines and HaCat cells to etoposide, cisplatin, and staurosporine. Induction of apoptosis in these cell types was generally associated with decreased levels of Mcl-1, XIAP, and Livin, and increased levels of p53, whereas levels of other apoptotic regulators were unaltered. These results provide insights into the potential roles of apoptosis in the function and transformation of epidermal melanocytes and keratinocytes.

Lentigo maligna and superficial spreading melanoma are different in their in situ phase: an immunohistochemical study

Clinical and pathologic observations have prompted the categorization of malignant melanoma into 4 subtypes. Although some authorities challenge the value of this classification, nevertheless it is generally accepted that lentigo maligna (LM), or melanoma on sun-damaged skin, has a different biological behavior than so-called superficial spreading melanoma (SSM), at least in the early stage of its evolution. To characterize some aspects of this different behavior, the in situ phase of SSM and LM was studied using immunohistochemical methods. Seventeen cases of SSM in situ and 13 cases of LM were chosen for the study. All cases qualified with strict histologic criteria. Sections from these lesions were stained with antibodies against HMB-45 antigen, basic fibroblast growth factor (bFGF), proliferating cell nuclear antigen (PCNA), and factor VIII. Semiquantitative analysis was performed. Cases classified as either LM or SSM corresponded well to the epidemiologic and clinical characteristics as described in the literature; that is, LM appeared in older patients and occurred mostly on the face, whereas SSM occurred mostly on the trunk and lower limbs. Although no difference in HMB-45 stain was observed, melanoctyes of SSM showed greater proliferative activity, as reflected by PCNA stain (P < 0.02) and higher levels of bFGF (P < 0.001), than melanocytes of LM. More blood vessels were counted under SSM than under LM (P < 0.05). These results are in accordance with the biological behavior of SSM and LM, that is, the longer in situ phase of the latter. bFGF is both a growth factor for melanocytes and an angiogentic factor. The differences in PCNA, a proliferation marker, and blood vessel count may be related to the bFGF effect. Thus this study reveals some of the biological differences between LM and SSM. Location and sun exposure habits may contribute to these differences, which already exist in the in situ phase.

Differentiation therapy of human cancer: basic science and clinical applications

Current cancer therapies are highly toxic and often nonspecific. A potentially less toxic approach to treating this prevalent disease employs agents that modify cancer cell differentiation, termed 'differentiation therapy.' This approach is based on the tacit assumption that many neoplastic cell types exhibit reversible defects in differentiation, which upon appropriate treatment, results in tumor reprogramming and a concomitant loss in proliferative capacity and induction of terminal differentiation or apoptosis (programmed cell death). Laboratory studies that focus on elucidating mechanisms of action are demonstrating the effectiveness of 'differentiation therapy,' which is now beginning to show translational promise in the clinical setting.

Responses to ultraviolet-B in cell lines from hereditary melanoma kindreds

Ultraviolet-B (UV-B) triggers a cascade of events involving cell cycle control genes leading ultimately to DNA repair or apoptosis. The hypothesis examined here is that the genetic abnormality predisposing to melanoma affects the ability of the cell to respond appropriately to UV-B, so favouring mutagenesis. Epstein-Barr virus-transformed lymphoblastoid cell lines from hereditary melanoma kindreds were irradiated with UV-B, and changes in p53, p21 and Bcl-2 expression and cell cycle phase distribution were analysed. Twenty-two cell lines were tested: 12 carriers of melanoma susceptibility and 10 non-carriers (unaffected first degree relatives). At 24 h after irradiation with 50 J/m2, 15 of the 22 cell lines showed a rise in G2/M. After 400 J/m2, all the cell lines showed a reduction or loss of G2/M and 17 of the 22 showed an S phase delay. More carriers than noncarriers of melanoma susceptibility showed significant S phase delay after 50 J/m2 (seven out of 12 carriers versus two out of 10 non-carriers). Six of the 10 pairs (carrier versus non-carrier) tested showed discordant cell cycle responses; however the nature of the difference was not universal. Bcl-2 reduction was seen 4 h post-irradiation in all the carriers and non-carriers. The p53 and p21 responses, although showing some individual variations, were not related to carrier status. These results show individual variations in response to UV-B irradiation among cell lines from the members of hereditary melanoma kindreds, but no consistent differences between carriers and non-carriers of melanoma susceptibility.

Expression and targeting of the apoptosis inhibitor, survivin, in human melanoma

The newly described apoptosis inhibitor survivin is expressed in many human cancers and appears to play a critical part in both apoptosis regulation and cell cycle progression. Its potential role in malignant melanoma is unknown. In a panel of 30 malignant melanomas, survivin was strongly expressed in all cases (15 of 15) of metastatic malignant melanomas and 13 of 15 cases of invasive malignant melanomas by immunohistochemistry. In invasive malignant melanomas, survivin was also expressed in the in-situ component of the lesion. Survivin expression was found in all cases (11 of 11) of nevi, but not in melanocytes in sections of normal skin. The apoptosis inhibitor bcl-2 was expressed in 26 of 30 cases, but generally at lower levels than that of infiltrating lymphocytes. The mitotic index, as assessed by MIB-1 staining, was consistently higher in metastatic than invasive malignant melanomas. Assessment of apoptotic index by in situ end-labeling revealed extremely low rates of apoptosis in most malignant melanomas. Survivin expression by western blotting was detected in four human metastatic malignant melanoma cell lines but not in cultured normal human melanocytes. Transfection of both YUSAC-2 and LOX malignant melanoma cells with green fluorescence protein-conjugated survivin anti-sense or green fluorescence protein-conjugated survivin dominant negative mutant (Cys84Ala) [corrected] resulted in increased apoptosis in the absence of other genotoxic stimuli. Two-color flow cytometry confirmed that YUSAC-2 cells transfected with survivin anti-sense expressed less endogenous survivin and exhibited an increased fraction of cells with sub-G1 DNA content. These data demonstrate that apoptosis inhibition by survivin may participate in the onset and progression of malignant melanomas, and suggest that therapeutic targeting of survivin may be beneficial in patients with recurrent or metastatic disease.

Natural killer cell lines kill autologous beta2-microglobulin-deficient melanoma cells: implications for cancer immunotherapy

Cancer vaccines used to generate specific cytotoxic T lymphocytes are not effective against tumor cells that have lost or suppressed expression of their class I major histocompatibility complex proteins. This loss is common in some cancers and particularly in metastatic lesions. We show that beta2-microglobulin-deficient class I-negative melanoma variants derived from patients undergoing specific T cell therapy are lysed by heterologous as well as autologous natural killer (NK) lines and clones, but not by specific T cells. Moreover, the minor NK cell fraction but not the major T cell fraction derived from heterologous lymphokine activated killer cells kills those tumor cell lines. ICAM-1 expression by the different class I protein deficient tumors was correlated with their sensitivity to lysis by NK cells. Adoptive autologous NK therapy may be an important supplement to consider in the design of new cancer immunotherapies.

Immunohistochemistry: a prognostic as well as diagnostic tool?

The assessment of proliferating cell populations has been used to aid in the differentiation of benign from malignant neoplasms, and it has been hoped that assessment of proliferation markers and oncogenic determinants holds information regarding prognosis. Various markers, including Ki-67, p53 protein, bcl-2, and proliferating cell nuclear or paraffin-embedded tissue. These determinants may prove useful in understanding the biology of certain neoplasms and may carry prognostic information that influences clinical management. Results in this developing field must always be interpreted in the clinical and histological context. This article reviews the applicability of some commonly available markers to selected skin disorders.