Intracellular sphingosine kinase 2-derived sphingosine-1-phosphate mediates epidermal growth factor-induced ezrin-radixin-moesin phosphorylation and cancer cell invasion.

The bioactive sphingolipid sphingosine-1-phosphate (S1P) mediates cellular proliferation, mitogenesis, inflammation, and angiogenesis. These biologies are mediated through S1P binding to specific GPCRs [sphingosine-1-phosphate receptor (S1PR)1-5] and some other less well-characterized intracellular targets. Ezrin-radixin-moesin (ERM) proteins, a family of adaptor molecules linking the cortical actin cytoskeleton to the plasma membrane, are emerging as critical regulators of cancer invasion via regulation of cell morphology and motility. Recently, we identified S1P as an acute ERM activator (via phosphorylation) through its action on S1PR2. In this work, we dissect the mechanism of S1P generation downstream of epidermal growth factor (EGF) leading to ERM phosphorylation and cancer invasion. Using pharmacologic inhibitors, small interfering RNA technologies, and genetic approaches, we demonstrate that sphingosine kinase (SK)2, and not SK1, is essential and sufficient in EGF-mediated ERM phosphorylation in HeLa cells. In fact, knocking down SK2 decreased ERM activation 2.5-fold. Furthermore, we provide evidence that SK2 is necessary to mediate EGF-induced invasion. In addition, overexpressing SK2 causes a 2-fold increase in HeLa cell invasion. Surprisingly, and for the first time, we find that this event, although dependent on S1PR2 activation, does not generate and does not require extracellular S1P secretion, therefore introducing a potential novel model of autocrine/intracrine action of S1P that still involves its GPCRs. These results define new mechanistic insights for EGF-mediated invasion and novel actions of SK2, therefore setting the stage for novel targets in the treatment of growth factor-driven malignancies.

Sphingosine-1-phosphate metabolism: A structural perspective.

Sphingolipids represent an important class of bioactive signaling lipids which have key roles in numerous cellular processes. Over the last few decades, the levels of bioactive sphingolipids and/or their metabolizing enzymes have been realized to be important factors involved in disease development and progression, most notably in cancer. Targeting sphingolipid-metabolizing enzymes in disease states has been the focus of many studies and has resulted in a number of pharmacological inhibitors, with some making it into the clinic as therapeutics. In order to better understand the regulation of sphingolipid-metabolizing enzymes as well as to develop much more potent and specific inhibitors, the field of sphingolipids has recently taken a turn toward structural biology. The last decade has seen the structural determination of a number of sphingolipid enzymes and effector proteins. In these terms, one of the most complete arms of the sphingolipid pathway is the sphingosine-1-phosphate (S1P) arm. The structures of proteins involved in the function and regulation of S1P are being used to investigate further the regulation of said proteins as well as in the design and development of inhibitors as potential therapeutics.

Sphingolipids in the DNA damage response.

Recently, sphingolipid metabolizing enzymes have emerged as important targets of many chemotherapeutics and DNA damaging agents and therefore play significant roles in mediating the physiological response of the cell to DNA damage. In this review we will highlight points of connection between the DNA damage response (DDR) and sphingolipid metabolism; specifically how certain sphingolipid enzymes are regulated in response to DNA damage and how the bioactive lipids produced by these enzymes affect cell fate.

The influence of lower lip position on the perceived attractiveness of chin prominence.

OBJECTIVES: To evaluate the influence of the lower lip prominence for varying degrees of chin prominence in the sagittal plane and to establish whether lower lip prominence affects the perceived desire for surgery. To assess differences in preference between orthodontists and laypeople as well as the effect of age, gender, and ethnicity of observers on perceptions of attractiveness and desire for surgery. MATERIALS AND METHODS: A silhouette of an idealized profile image was created. The image was manipulated to create six images demonstrating different degrees of retrogenia and progenia altered in 4-mm increments from -12 mm to +12 mm and six images demonstrating chin and lower lip prominence in 4-mm increments from -12 mm to +12 mm. One hundred laypeople and 30 orthodontists ranked the images from the most to the least attractive. A duplicate of one of the images was used in order to assess intraexaminer reliability. RESULTS: The amount and direction of sagittal chin position and the prominence of the lower lip were found to have a significant effect on image rank. Chin protrusion was less attractive than retrusion and surgery was desired more often for these images. The overall direction of opinion was the same for laypeople and orthodontists. CONCLUSIONS: The chin prominence observed in a progenic patient is deemed less attractive than the combined chin and lower lip prominence observed in a patient with mandibular prognathism. In profiles with a more prominent chin a more protrusive lower lip position was preferred. When the chin was retrusive, a normal lower lip position was preferred to a retrusive lip.

Crystal structure of folliculin reveals a hidDENN function in genetically inherited renal cancer.

Mutations in the renal tumour suppressor protein, folliculin, lead to proliferative skin lesions, lung complications and renal cell carcinoma. Folliculin has been reported to interact with AMP-activated kinase, a key component of the mammalian target of rapamycin pathway. Most cancer-causing mutations lead to a carboxy-terminal truncation of folliculin, pointing to a functional importance of this domain in tumour suppression. We present here the crystal structure of folliculin carboxy-terminal domain and demonstrate that it is distantly related to differentially expressed in normal cells and neoplasia (DENN) domain proteins, a family of Rab guanine nucleotide exchange factors (GEFs). Using biochemical analysis, we show that folliculin has GEF activity, indicating that folliculin is probably a distantly related member of this class of Rab GEFs.

International Prognostic Score in advanced-stage Hodgkin's lymphoma: altered utility in the modern era.

PURPOSE: The International Prognostic Score (IPS) is the most widely used risk stratification index for Hodgkin's lymphoma (HL). It is based on patients treated before 1992 and predicts 5-year freedom from progression (FFP) and overall survival (OS) ranging from 42% to 84% and 56% to 89%, respectively. The IPS has not been validated in a recently treated population in which outcomes have improved compared with historic results. PATIENTS AND METHODS: By using the British Columbia Cancer Agency Lymphoid Cancer Database, we identified all patients age ≥ 16 years newly diagnosed with advanced-stage HL (stage III to IV, or stage I to II with "B" symptoms or bulky disease ≥ 10 cm) from 1980 to 2010, treated with curative intent with doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) or an ABVD-equivalent regimen with complete clinical information. RESULTS: In all, 740 patients were identified. Five-year FFP and OS were 78% and 90%, respectively. The IPS was prognostic for both FFP (P < .001) and OS (P < .001), with 5-year FFP ranging from 62% to 88% and 5-year OS ranging from 67% to 98%. Analysis limited to patients age 16 to 65 years (n = 686) demonstrated a narrower range of outcomes, with 5-year FFP ranging from 70% to 88% and 5-year OS ranging from 73% to 98%. CONCLUSION: The IPS remains prognostic for advanced-stage HL, but the range of outcomes has narrowed considerably. This improvement in outcome with ABVD should be acknowledged before consideration of alternate initial therapies and when comparing results from current trials with those of historic controls.

Prognostic implications of extranodal involvement in patients with diffuse large B-cell lymphoma treated with rituximab and cyclophosphamide, doxorubicin, vincristine, and prednisone.

The addition of rituximab (R) to standard CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) chemotherapy has altered the significance of previously recognized prognostic factors. We sought to re-examine the prognostic utility of (1) the number of extranodal sites of disease involvement, and (2) a primary extranodal presentation in patients with DLBCL treated with immunochemotherapy. We retrospectively analyzed all patients with DLBCL diagnosed between January 1979 and May 2006 who were treated with an anthracycline-based therapy with curative intent. In all, 1781 patients were identified, of whom 513 (29%) received R-CHOP. In the R-CHOP group, extranodal involvement as defined by the International Prognostic Index (>or=2 sites) was not prognostic on multivariate analysis, but the presence of any extranodal involvement (>or=1 site) was associated with decreased progression-free survival (HR 1.6, 95% CI 1.1-2.4, p = 0.024) and overall survival (HR 1.8, 95% CI 1.1-2.7, p = 0.011). A total of 133 (26%) R-CHOP treated patients presented with primary extranodal DLBCL. There was no difference in outcome between patients with primary extranodal and nodal DLBCL, and no primary site of involvement was associated with an inferior outcome. In patients with DLBCL treated with R-CHOP, the presence of extranodal disease remains prognostic, whereas a primary extranodal presentation did not affect outcome.

Rapid infusion rituximab in combination with corticosteroid-containing chemotherapy or as maintenance therapy is well tolerated and can safely be delivered in the community setting.

The increasing usage of rituximab in the management of non-Hodgkin lymphoma (NHL) has created huge logistical challenges with respect to the delivery of this time- and labor-intensive drug. To address these challenges, we developed and tested the feasibility of a 90-minute infusion schedule for rituximab (20% of the dose administered in the first 30 minutes, remaining 80% administered over 60 minutes). A safety analysis performed in 150 patients receiving rituximab with corticosteroid-containing chemotherapy and 56 patients receiving rituximab as maintenance therapy demonstrated that this schedule was well tolerated, with no grade 3 or 4 infusion reactions observed. In addition, no increase in minor reactions was noted. More than 1200 patients have been treated with this rapid rituximab infusion schedule in the province of British Columbia (BC), demonstrating its safety in the community setting. The adoption of this 90-minute schedule as standard practice has had a positive impact on resource utilization.

Introduction of combined CHOP plus rituximab therapy dramatically improved outcome of diffuse large B-cell lymphoma in British Columbia.

PURPOSE: For more than two decades, cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) has been the standard therapy for diffuse large B-cell lymphoma (DLBCL). The addition of rituximab to CHOP has been shown to improve outcome in elderly patients with DLBCL. We conducted a population-based analysis to assess the impact of this combination therapy on adult patients with DLBCL in the province of British Columbia (BC). METHODS: We compared outcomes during a 3-year period; 18 months before (prerituximab) and 18 months after (postrituximab) institution of a policy recommending the combination of CHOP and rituximab for all patients with newly diagnosed advanced-stage (stage III or IV or stage I or II with "B" symptoms or bulky [> 10 cm] disease) DLBCL. RESULTS: A total of 292 patients were evaluated; 140 in the prerituximab group (median follow-up, 42 months) and 152 in the postrituximab group (median follow-up, 24 months). Both progression-free survival (risk ratio, 0.56; 95% CI, 0.39 to 0.81; P = .002) and overall survival (risk ratio, 0.40; 95% CI, 0.27 to 0.61, P < .0001) were significantly improved in the postrituximab group. After controlling for age and International Prognostic Index score, era of treatment remained a strong independent predictor of progression-free survival (risk ratio, 0.59; 95% CI, 0.41 to 0.85; P = .005) and overall survival (risk ratio, 0.43; 95% CI, 0.29 to 0.66; P < .001). The benefit of treatment in the postrituximab era was present regardless of age. CONCLUSION: The addition of rituximab to CHOP chemotherapy has resulted in a dramatic improvement in outcome for DLBCL patients of all ages in the province of BC.