Konstantinos Lasithiotakis

Age and gender are significant independent predictors of survival in primary cutaneous melanoma.

The aim was to identify age‐ related and gender‐related differences in the clinical presentation and outcome of patients with primary cutaneous melanoma (CM).

Combined Inhibition of MAPK and mTOR Signaling Inhibits Growth, Induces Cell Death, and Abrogates Invasive Growth of Melanoma Cells

The RAS-RAF-MEK-ERK and PI3K-AKT-mTOR signaling pathways are activated through multiple mechanisms and appear to play a major role in melanoma progression. Herein, we examined whether targeting the RAS-RAF-MEK-ERK pathway with the RAF inhibitor sorafenib and/or the PI3K-AKT-mTOR pathway with the mTOR inhibitor rapamycin has therapeutic effects against melanoma. A combination of sorafenib (4 microM) with rapamycin (10 nM) potentiated growth inhibition in all six metastatic melanoma cell lines tested. The absolute enhancement of growth inhibition rates ranged from 13.0-27.8% in different cell lines (P<0.05, combination treatment vs monotreatment). Similar results were obtained with combinations of the MEK inhibitors U0126 (30 microM) or PD98059 (50 microM) with rapamycin (10 nM). The combined treatment of melanoma cells with sorafenib and rapamycin led to an approximately twofold increase of cell death compared with sorafenib monotreatment (P<0.05) as assessed by propidium iodide staining and cell death detection ELISA. Moreover, sorafenib in combination with rapamycin completely suppressed invasive melanoma growth in organotypic culture mimicking the physiological context. These effects were associated with complete downregulation of the antiapoptotic proteins Bcl-2 and Mcl-1. Sorafenib combined with rapamycin appears to be a promising strategy for the effective treatment of melanoma and merits clinical investigation.

The incidence and mortality of cutaneous melanoma in Southern Germany: trends by anatomic site and pathologic characteristics, 1976 to 2003.

Cutaneous melanoma (CM) incidence and mortality have risen dramatically during the past 2 generations, particularly among Caucasian populations. Detailed, long‐term trends of CM in relation to clinical and pathologic characteristics in a Central European population have not been published to date.

Determinants of survival in patients with brain metastases from cutaneous melanoma

Background:This retrospective study aimed to identify prognostic factors in patients with brain metastases from cutaneous melanoma.Methods:In all, 265 patients under regular screening according to valid national surveillance guidelines were included in the study. Kaplan–Meier analyses were performed to estimate and to compare overall survival. Cox modeling was used to identify independent determinants of the overall survival, which were used in explorative classification and regression tree analysis to define meaningful prognostic groups.Results:In total, 55.5% of our patients presented with two or less brain metastases, 82.6% had concurrent extracranial metastasis and 64% were asymptomatic and diagnosed during surveillance scans. In all, 36.7% were candidates for local treatment (neurosurgery or stereotactic radiosurgery (SRS)). The median overall survival of the entire collective was 5.0 months (95% confidence interval: 4.3–5.7). Favourable independent prognostic factors were: normal pre-treatment level of serum lactate dehydrogenase (P<0.001), administered therapy (neurosurgery or SRS vs other, P=0.002), number of brain metastases (single vs multiple, P=0.032) and presence of bone metastasis (false vs true, P=0.044). Three prognostic groups with significantly different overall survival were identified. Candidates for local treatment (group I) had the longer median survival (9 months). Remaining patients could be further classified in two groups on the basis of serum lactate dehydrogenase.Conclusion:Applied treatment and serum lactate dehydrogenase levels were independent predictors of survival of patients with brain metastases from cutaneous melanoma. Patients receiving local therapy have overall survival comparable with general stage IV melanoma patients.

Inhibition of PI3K-AKT-mTOR Signaling Sensitizes Melanoma Cells to Cisplatin and Temozolomide

In melanoma, the PI3K-AKT-mTOR (AKT) and RAF-MEK-ERK (MAPK) signaling pathways are constitutively activated and appear to play a role in chemoresistance. Herein, we investigated the effects of pharmacological AKT and MAPK pathway inhibitors on chemosensitivity of melanoma cells to cisplatin and temozolomide. Chemosensitivity was tested by examining effects on growth, cell cycle, survival, expression of antiapoptotic proteins, and invasive tumor growth of melanoma cells in monolayer and organotypic culture, respectively. MAPK pathway inhibitors did not significantly increase chemosensitivity. AKT pathway inhibitors consistently enhanced chemosensitivity yielding an absolute increase of cell growth inhibition up to 60% (P<0.05, combination therapy vs monotherapy with inhibitors or chemotherapeutics). Cotreatment of melanoma cells with AKT pathway inhibitors and chemotherapeutics led to a 2- to 3-fold increase of apoptosis (P<0.05, combination therapy vs monotherapy) and completely suppressed invasive tumor growth in organotypic culture. These effects were associated with suppression of the antiapoptotic Bcl-2 family protein Mcl-1. These data suggest that inhibition of the PI3K-AKT-mTOR pathway potently increases sensitivity of melanoma cells to chemotherapy.

Vemurafenib Potently Induces Endoplasmic Reticulum Stress–Mediated Apoptosis in BRAFV600E Melanoma Cells

Drug resistance in melanomas may be overcome by therapies that trigger endoplasmic reticulum stress. Stressing Out Resistance Many melanomas harbor a form of the kinase BRAF with an amino acid substitution (V600E) that renders the protein constitutively active. The mutant BRAF drives cancer growth by activating extracellular signal–regulated kinase (ERK), which promotes cell proliferation and survival. The BRAFV600E kinase inhibitor vemurafenib is initially an effective therapy for melanoma but loses its efficacy because the tumor cells become drug-resistant. Beck et al. found that vemurafenib inhibited survival signaling mediated by ERK and induced endoplasmic reticulum (ER) stress, a form of cellular stress that can culminate in apoptosis. Combined application of vemurafenib with the ER stress inducer thapsigargin to BRAFV600E melanoma cell lines that were resistant to vemurafenib resulted in an enhanced ER stress response and apoptosis. Their findings indicate a potential strategy to overcome drug resistance in BRAF-mutated melanoma. The V600E mutation in the kinase BRAF is frequently detected in melanomas and results in constitutive activation of BRAF, which then promotes cell proliferation by the mitogen-activated protein kinase signaling pathway. Although the BRAFV600E kinase inhibitor vemurafenib has remarkable antitumor activity in patients with BRAFV600E-mutated melanoma, its effects are limited by the onset of drug resistance. We found that exposure of melanoma cell lines with the BRAFV600E mutation to vemurafenib decreased the abundance of antiapoptotic proteins and induced intrinsic mitochondrial apoptosis. Vemurafenib-treated melanoma cells showed increased cytosolic concentration of calcium, a potential trigger for endoplasmic reticulum (ER) stress, which can lead to apoptosis. Consistent with an ER stress–induced response, vemurafenib decreased the abundance of the ER chaperone protein glucose-regulated protein 78, increased the abundance of the spliced isoform of the transcription factor X-box binding protein 1 (XBP1) (which transcriptionally activates genes involved in ER stress responses), increased the phosphorylation of the translation initiation factor eIF2α (which would be expected to inhibit protein synthesis), and induced the expression of ER stress–related genes. Knockdown of the ER stress response protein activating transcription factor 4 (ATF4) significantly reduced vemurafenib-induced apoptosis. Moreover, the ER stress inducer thapsigargin prevented invasive growth of tumors formed from vemurafenib-sensitive melanoma cells in vivo. In melanoma cells with low sensitivity or resistance to vemurafenib, combination treatment with thapsigargin augmented or induced apoptosis. Thus, thapsigargin or other inducers of ER stress may be useful in combination therapies to overcome vemurafenib resistance.

Costs of the detection of metastases and follow-up examinations in cutaneous melanoma.

At present, no universally accepted recommendations exist for cutaneous melanoma follow-up. Various surveillance strategies, some associated with significant cost, others of uncertain value, are routinely used. This study aimed to evaluate of the costs incurred for varied surveillance strategies practiced in Europe and the USA. One thousand nine hundred and sixty-nine cutaneous melanoma patients with stage I–III disease attending the Department of Dermatology, University of Tuebingen for follow-up between 1996 and 1998 participated in the study. Routine surveillance consisted of cutaneous examination, lymph node and abdomen sonography, chest radiograph (CR) and blood tests. The costs incurred were based upon the 2004 German official scale for medical reimbursement and the 2004 Medicare fee reimbursement schedule (USA). The total charges were based on the number of recurrences detected per stage. Recurrences were detected in 1.5% of patients with stage I, 18.0% in stage II, and 68.6% in stage III. Physical examination was the most effective method, detecting 50.0% of recurrences. Lymph node sonography was effective in stage II–III, detecting 13.2% of recurrences; CR and abdominal sonography, detecting 4.5 and 3.4% of recurrences, were deemed beneficial in stage III. Blood tests detected 1.4% of recurrences and were deemed to be ineffective. Computed tomography scans were valuable in clarifying ambiguous findings and helping to detect 22.5% of recurrences (1.9% in stage I, 1.9% in stage II, and 18.6% in stage III). A risk-adapted surveillance strategy for stage I–II including thorough history, physical examination and lymph node sonography but omitting CR, blood work and abdomen sonography, seems appropriate and cost effective.

Cutaneous melanoma in the elderly: epidemiology, prognosis and treatment.

The incidence and mortality of cutaneous melanoma (CM) has increased over the last decades in fair-skinned populations. Incidence and mortality, as well as rates of increase, have been significantly higher in elderly people compared with younger age groups. Lower survival rates from CM among elderly are mainly the result of late diagnosis of tumors with dismal prognostic features. Expansion of current preventive strategies to include older age groups is therefore warranted. Despite differences in clinical presentation and pathological characteristics of CM in the elderly, there is no evidence that primary surgical treatment should differ from that proposed generally for melanoma. However, the rate of positive sentinel node dissection decreases with age, even though overall survival is shorter in older patients, a paradox that remains to be explained. The use of adjuvant treatment with interferon-&agr; in elderly patients requires careful discussion of the risks and benefits, especially when serious illness coexists. For metastatic melanoma, complete metastasectomy is the only treatment associated with benefit for overall survival. However, careful selection of surgical oncogeriatric candidates is necessary, probably with the use of tools to provide a comprehensive geriatric assessment, to identify patients more likely to benefit from this treatment. In the absence of any effective systemic treatment for disseminated CM, new therapeutic agents are urgently needed. Practical means to improve accrual of older patients in clinical trials are necessary to provide better evidence for their treatment.

The farnesyl transferase inhibitor lonafarnib inhibits mTOR signaling and enforces sorafenib-induced apoptosis in melanoma cells.

Farnesyl transferase inhibitors (FTIs) inhibit the farnesylation of proteins, including RAS and RHEB (Ras homolog enriched in brain). RAS signals to the RAF-MEK-ERK (MAPK) and PI3K-AKT-mTOR (AKT) signaling pathways, which have a major role in melanoma progression. RHEB positively regulates mammalian target of rapamycin (mTOR). We investigated the effects of the FTI lonafarnib alone and in combination with MAPK (mitogen-activated protein kinase) or AKT (acutely transforming retrovirus AKT8 in rodent T-cell lymphoma) pathway inhibitors on proliferation, survival, and invasive tumor growth of melanoma cells. Lonafarnib alone did not sufficiently inhibit melanoma cell growth. Combinations of lonafarnib with AKT pathway inhibitors did not significantly increase melanoma cell growth inhibition. In contrast, combinations of lonafarnib with MAPK pathway inhibitors yielded additional growth-inhibiting effects. In particular, the combination of the FTI lonafarnib with the pan-RAF inhibitor sorafenib synergistically inhibited melanoma cell growth, significantly enhanced sorafenib-induced apoptosis, and completely suppressed invasive tumor growth in monolayer and organotypic cultures, respectively. Apoptosis induction was associated with upregulation of the endoplasmic reticulum stress-related transcription factors p8 and CHOP (CAAT/enhancer binding protein (C/EBP) homologous protein), and downregulation of the antiapoptotic Bcl-2 (B-cell lymphoma-2) family protein Mcl-1(myeloid cell leukemia 1). Lonafarnib did not affect MAPK and AKT but did affect mTOR signaling. Together, these findings suggest that the FTI lonafarnib inhibits mTOR signaling and enforces sorafenib-induced apoptosis in melanoma cells and may therefore represent an effective alternative for melanoma treatment.

Improvement of overall survival of patients with cutaneous melanoma in Germany, 1976-2001: which factors contributed?

A hypothesis generated a retrospective analysis of the improvement of survival over time in patients with cutaneous melanoma (CM) in order to identify factors contributing to this progress.