Sara M. Kantrow

Conditional ablation of Ikkb inhibits melanoma tumor development in mice

Several lines of evidence suggest that tumor cells show elevated activity of the NF-kappaB transcription factor, a phenomenon often resulting from constitutive activity of IkappaB kinase beta (IKKbeta). However, others have found that loss of NF-kappaB activity or IKKbeta is tumor promoting. The role of NF-kappaB in tumor progression is therefore controversial and varies with tumor type. We sought to more extensively investigate the role IKKbeta in melanoma tumor development by specifically disrupting Ikkb in melanocytes in an established mouse model of spontaneous melanoma, whereby HRasV12 is expressed in a melanocyte-specific, doxycycline-inducible manner in mice null for the gene encoding the tumor suppressor inhibitor cyclin-dependent kinase 4/alternative reading frame (Ink4a/Arf). Our results show that Ink4a/Arf-/- mice with melanocyte-specific deletion of Ikkb were protected from HRasV12-initiated melanoma only when p53 was expressed. This protection was accompanied by cell cycle arrest, with reduced cyclin-dependent kinase 2 (Cdk2), Cdk4, Aurora kinase A, and Aurora kinase B expression. Increased p53-mediated apoptosis was also observed, with decreased expression of the antiapoptotic proteins Bcl2 and survivin. Enhanced stabilization of p53 involved increased phosphorylation at Ser15 and reduced phosphorylation of double minute 2 (Mdm2) at Ser166. Together, our findings provide genetic and mechanistic evidence that mutant HRas initiation of tumorigenesis requires Ikkbeta-mediated NF-kappaB activity.

Targeting aurora kinases limits tumour growth through DNA damage-mediated senescence and blockade of NF-κB impairs this drug-induced senescence

Oncogene‐induced senescence can provide a protective mechanism against tumour progression. However, production of cytokines and growth factors by senescent cells may contribute to tumour development. Thus, it is unclear whether induction of senescence represents a viable therapeutic approach. Here, using a mouse model with orthotopic implantation of metastatic melanoma tumours taken from 19 patients, we observed that targeting aurora kinases with MLN8054/MLN8237 impaired mitosis, induced senescence and markedly blocked proliferation in patient tumour implants. Importantly, when a subset of tumour‐bearing mice were monitored for tumour progression after pausing MLN8054 treatment, 50% of the tumours did not progress over a 12‐month period. Mechanistic analyses revealed that inhibition of aurora kinases induced polyploidy and the ATM/Chk2 DNA damage response, which mediated senescence and a NF‐κB‐related, senescence‐associated secretory phenotype (SASP). Blockade of IKKβ/NF‐κB led to reversal of MLN8237‐induced senescence and SASP. Results demonstrate that removal of senescent tumour cells by infiltrating myeloid cells is crucial for inhibition of tumour re‐growth. Altogether, these data demonstrate that induction of senescence, coupled with immune surveillance, can limit melanoma growth.

RAF265 inhibits the growth of advanced human melanoma tumors.

Purpose: The purpose of this preclinical study was to determine the effectiveness of RAF265, a multikinase inhibitor, for treatment of human metastatic melanoma and to characterize traits associated with drug response. Experimental Design: Advanced metastatic melanoma tumors from 34 patients were orthotopically implanted to nude mice. Tumors that grew in mice (17 of 34) were evaluated for response to RAF265 (40 mg/kg, every day) over 30 days. The relation between patient characteristics, gene mutation profile, global gene expression profile, and RAF265 effects on tumor growth, mitogen-activated protein/extracellular signal-regulated kinase (MEK)/extracellular signal-regulated kinase (ERK) phosphorylation, proliferation, and apoptosis markers was evaluated. Results: Nine of the 17 tumors that successfully implanted (53%) were mutant BRAF (BRAFV600E/K), whereas eight of 17 (47%) tumors were BRAF wild type (BRAFWT). Tumor implants from 7 of 17 patients (41%) responded to RAF265 treatment with more than 50% reduction in tumor growth. Five of the 7 (71%) responders were BRAFWT, of which 1 carried c-KITL576P and another N-RASQ61R mutation, while only 2 (29%) of the responding tumors were BRAFV600E/K. Gene expression microarray data from nonimplanted tumors revealed that responders exhibited enriched expression of genes involved in cell growth, proliferation, development, cell signaling, gene expression, and cancer pathways. Although response to RAF265 did not correlate with pERK1/2 reduction, RAF265 responders did exhibit reduced pMEK1, reduced proliferation based upon reduced Ki-67, cyclin D1 and polo-like kinase1 levels, and induction of the apoptosis mediator BCL2-like 11. Conclusions: Orthotopic implants of patient tumors in mice may predict prognosis and treatment response for melanoma patients. A subpopulation of human melanoma tumors responds to RAF265 and can be characterized by gene mutation and gene expression profiles. Clin Cancer Res; 18(8); 2184–98. ©2012 AACR.

Spitzoid melanoma in children: clinicopathological study and application of immunohistochemistry as an adjunct diagnostic tool

Introduction:  The term spitzoid melanoma (SM) is reserved for a rare group of tumors with striking resemblance to Spitz nevus, often developing in children diagnosed in retrospect after the development of metastases.

Prognostic Factors for Melanoma in Children and Adolescents: A Clinicopathologic, Single-Center Study of 137 Patients

Cutaneous melanoma in childhood is rare; therefore, its prognostic factors and biologic behavior and the effectiveness of adjuvant diagnostic techniques in this group remain mostly unknown.

Expression of activated Akt in benign nevi, Spitz nevi and melanomas.

Background:  Activated Akt expression (p‐Akt) is reportedly increased in many melanomas as compared with benign nevi. The purpose of this study was to evaluate and compare p‐Akt immunohistological staining in benign nevi, Spitz nevi and primary melanomas.

Ikk4a/Arf Inactivation with Activation of the NF-κB/IL-6 Pathway Is Sufficient to Drive the Development and Growth of Angiosarcoma

Although human angiosarcoma has been associated frequently with mutational inactivation of the tumor suppressor gene Ink4a/Arf, the underlying mechanisms have not been delineated. Here we report that malignant angiosarcoma is associated with high levels of RelA/NF-κB and IL-6 in contrast to normal vessels or benign hemagiomas. Studies of Ink4a/Arf deficient mice not only recapitulate genetic traits observed in human angiosarcoma, but also unveil a possible therapeutic link comprised of the NF-kB/IL-6/Stat3 signaling axis. In Ink4a/Arf(-/-) cells, NF-κB controlled Stat3 signaling by transcriptionally controlling the expression of IL-6, gp130, and Jak2. Further, IL-6 mediated Stat3 signaling through the sIL-6R. Inhibition of Ikkβ solely in myeloid cells was insufficient to block angiosarcoma development; in contrast, systemic inhibition of Ikkβ, IL-6, or Stat3 markedly inhibited angiosarcoma growth. Our findings offer clinical implications for targeting the NF-kB/IL-6/STAT3 pathway as a rational strategy to treat angiosarcoma.

Cutaneous epithelioid angiomatous nodule: report of a case and absence of microsatellite instability.

To the Editor, The differential diagnosis of cutaneous epithelioid vascular neoplasms includes those with benign (epithelioid hemangioma or angiolymphoid hyperplasia with eosinophilia, Kimura’s disease, bacillary angiomatosis and epithelioid pyogenic granuloma) and malignant behavior (epithelioid hemangioendothelioma and epithelioid angiosarcoma). In 2004, Brenn and Fletcher described a cutaneous epithelioid vascular neoplasm not easily classified in these categories. This entity, termed cutaneous epithelioid angiomatous nodule (CEAN), is acquired, presents as a small papule or nodule most commonly on the trunk and extremities and pursues a benign clinical course. Histologically, these lesions appear as circumscribed nodules, typically located in the superficial dermis, and are comprised of epithelioid endothelial cells containing vesicular nuclei with pronounced nucleoli and abundant eosinophilic to clear cytoplasm with intracytoplasmic vacuoles. Mitotic figures and focal intralesional endothelial-lined channels are often appreciated. Mild fibroplasia is present at the periphery of these nodules with an inflammatory infiltrate of lymphocytes and plasma cells. Eosinophils are distributed throughout the tumors in varying numbers. Cells stain positively for endothelial markers (CD31, CD34 or factor-VIII-related antigen) and negatively for S100, cytokeratin and human herpes virus type 8 (HHV8). Since the original description, two additional cases of CEAN have been reported. We describe the clinical and pathological features of a third case of CEAN. Because microsatellite instability (MSI) is a form of genetic instability reported in a number of cutaneous neoplasms, we also examined the lesion for evidence of MSI. A 43-year-old immunocompetent white woman presented to her primary care physician with a 9month history of a pruritic papule on her upper back believed to have resulted from an insect bite. Over a period of several months, the papule increased in size, became irritated and bled intermittently. The patient was otherwise healthy and taking no medications. A shave biopsy was performed. Pathology revealed a well-circumscribed, nonencapsulated nodule in the superficial dermis comprised of large epithelioid cells with eosinophilic to clear cytoplasm and vesicular nuclei with prominent nucleoli (Fig. 1). These epithelioid cells were CD31 positive (Fig. 2). Intracytoplasmic vacuolar spaces were appreciated (Fig. 3). At the periphery of the lesion, there was a mixed inflammatory infiltrate containing lymphocytes and plasma cells. There were no infiltrating neutrophils or clumps of amphophilic granular material to suggest a diagnosis of bacillary angiomatosis. Using a combination of fluorescent-labeled mononucleotide (BAT-25 and BAT-26) and dinucleotide (D5S346, D17S250, D2S123, D19S206 and D19S178) markers, we used a polymerase chain reaction-based assay to examine this lesion for MSI.

Necrotizing vasculitis with a polyarteritis nodosa-like pattern and selective immunoglobulin A deficiency: Case report and review of the literature

Selective immunoglobulin A deficiency (IgAD) is a primary immunodeficiency disease characterized by low levels (< 7 mg/dl) of serum immunoglobulin (Ig) A and normal serum levels of IgG and IgM. Patients with IgAD have increased risk for recurrent respiratory and gastrointestinal infections, autoimmune disease, asthma and allergy. A 26‐year‐old woman was admitted with sudden onset of painful cutaneous lesions on her lower extremities, pyrexia and arthromyalgia. Her medical history was remarkable for recurrent respiratory tract infections, self‐limited episodes of acute diarrhea, atopy, splenomegaly and a 4‐year history of a lung granulomatous lesion. Laboratory and imaging tests ruled out severe life‐threatening infection, connective tissue disease and neoplasm. Serum protein electrophoresis showed a low IgA serum level (6.67 mg/dl), with normal serum levels of IgG and IgM, conducting to a diagnosis of selective IgAD. A skin biopsy showed necrotizing vasculitis without any sign of internal organ disease. We report a patient with IgAD and granulomatous involvement of lungs, spleen and medium‐sized arteries of the skin. Although IgAD results from a failure of B‐cell differentiation, we propose that deregulated immune response with production of cross‐reactive antibodies and hyperstimulation of T cells and macrophages could contribute to this widespread granulomatous reaction.

Nephrogenic systemic fibrosis: report of an additional case with granulomatous inflammation.

Nephrogenic systemic fibrosis (NSF) is a novel disease entity described over the past 10 years. NSF is a progressive systemic fibrosing disorder that occurs arguably exclusively in patients with impaired renal function who have been exposed to gadolinium-containing contrast agents. As no single clinical or histopathologic finding is diagnostic of NSF, a careful review of the cumulative characteristics of each case is essential in making a correct diagnosis. The spectrum of histologic variants of NSF continues to expand, including a report of NSF mimicking erythema nodosum and several case reports of NSF with giant cells and calcification. We report an additional case of NSF with the uncommon pathologic features of granulomatous and lymphocytic inflammation in the fibrous septae similar to erythema nodosum.