SAM-Competitive PRMT5 Inhibitor PF-06939999 Demonstrates Antitumor Activity in Splicing Dysregulated NSCLC with Decreased Liability of Drug Resistance.

Protein arginine methyltransferase 5 (PRMT5) overexpression in hematologic and solid tumors methylates arginine residues on cellular proteins involved in important cancer functions including cell-cycle regulation, mRNA splicing, cell differentiation, cell signaling, and apoptosis. PRMT5 methyltransferase function has been linked with high rates of tumor cell proliferation and decreased overall survival, and PRMT5 inhibitors are currently being explored as an approach for targeting cancer-specific dependencies due to PRMT5 catalytic function. Here, we describe the discovery of potent and selective S-adenosylmethionine (SAM) competitive PRMT5 inhibitors, with in vitro and in vivo characterization of clinical candidate PF-06939999. Acquired resistance mechanisms were explored through the development of drug resistant cell lines. Our data highlight compound-specific resistance mutations in the PRMT5 enzyme that demonstrate structural constraints in the cofactor binding site that prevent emergence of complete resistance to SAM site inhibitors. PRMT5 inhibition by PF-06939999 treatment reduced proliferation of non-small cell lung cancer (NSCLC) cells, with dose-dependent decreases in symmetric dimethyl arginine (SDMA) levels and changes in alternative splicing of numerous pre-mRNAs. Drug sensitivity to PF-06939999 in NSCLC cells associates with cancer pathways including MYC, cell cycle and spliceosome, and with mutations in splicing factors such as RBM10. Translation of efficacy in mouse tumor xenograft models with splicing mutations provides rationale for therapeutic use of PF-06939999 in the treatment of splicing dysregulated NSCLC.

Targeting S-adenosylmethionine biosynthesis with a novel allosteric inhibitor of Mat2A.

S-Adenosyl-L-methionine (SAM) is an enzyme cofactor used in methyl transfer reactions and polyamine biosynthesis. The biosynthesis of SAM from ATP and L-methionine is performed by the methionine adenosyltransferase enzyme family (Mat; EC 2.5.1.6). Human methionine adenosyltransferase 2A (Mat2A), the extrahepatic isoform, is often deregulated in cancer. We identified a Mat2A inhibitor, PF-9366, that binds an allosteric site on Mat2A that overlaps with the binding site for the Mat2A regulator, Mat2B. Studies exploiting PF-9366 suggested a general mode of Mat2A allosteric regulation. Allosteric binding of PF-9366 or Mat2B altered the Mat2A active site, resulting in increased substrate affinity and decreased enzyme turnover. These data support a model whereby Mat2B functions as an inhibitor of Mat2A activity when methionine or SAM levels are high, yet functions as an activator of Mat2A when methionine or SAM levels are low. The ramification of Mat2A activity modulation in cancer cells is also described.

Incidence of mechanical malfunction in low-profile subcutaneous implantable venous access devices in patients receiving chemotherapy for gynecologic malignancies.

OBJECTIVE: The purpose of this study was to investigate the incidence of mechanical complications associated with low-profile subcutaneous implantable venous access devices in gynecologic oncology patients. METHODS: Gynecologic oncology patients with low-profile Port-a-Caths implanted between March 2005 and July 2006 were identified into a computerized database. Patient demographics, operative complications, number of chemotherapy cycles, duration of implantation, and mechanical complications were collected. Primary outcomes included port leakage, catheter fracture, and catheter embolization. RESULTS: 112 patients underwent 115 Port-a-Cath placements with low profile single-lumen plastic ports with Groshong-valved catheters. Mean Port-a-Cath indwelling duration was 197 days (range: 4-395) with a mean number of 12 chemotherapy cycles (range 0-64). The cumulative complication rate necessitating removal or replacement was 15%. Of the 14 Port-a-Caths removed, ten (8.7%) were secondary to mechanical malfunction: one for leakage at the port site, two for catheter fracture, and seven for fracture with catheter embolization to the heart or pulmonary vasculature-most commonly the right ventricle. Patients with embolization were asymptomatic and all embolized catheters were successfully retrieved by interventional radiology without complications. CONCLUSIONS: The rates of catheter fracture and embolization have previously been reported to be low in patients with subcutaneous Port-a-Caths, and have not been studied in patients receiving low-profile subcutaneous Port-a-Caths. This study suggests that catheter fracture may be more common (8.7%) and must be considered in patients with malfunctioning low-profile Port-a-Caths. Embolized catheters can be removed by interventional radiology without significant adverse affects.

A cohort study evaluating robotic versus laparotomy surgical outcomes of obese women with endometrial carcinoma.

OBJECTIVE: Minimally invasive surgery offers advantages for management of obese patients, but technical difficulty often deters its utilization. Compared to laparotomy, robotic surgery should allow comparable staging and improved surgical outcomes. Therefore, we evaluated outcomes in robotic and laparotomy cohorts of obese women with endometrial cancer at our institution. METHODS: Retrospective robotic and laparotomy cohorts of obese women (BMI ≥ 30 kg/m(2)) undergoing surgical management of primary endometrial cancer from March 2006 to March 2009 were formulated utilizing a computerized database. Patient demographics, operative statistics, peri-operative complications, and pathologic details were collected in an intent to treat analysis. Chi-square or Fisher's exact test and t-test were used for statistical analysis. RESULTS: 73 women underwent robotic surgical management, 11% converted to laparotomy. Mean BMI (39.8 vs. 41.9, p=0.152), number of co-morbidities (2.49 vs. 2.62, p=0.690), number of previous surgeries (0.97 vs. 0.94, p=0.841), and lymphadenectomies performed (65.8% vs. 56.7%, p=0.227) were similar between cohorts. Total lymph nodes obtained were not statistically different between cohorts (8.01 vs. 7.24, p=0.505). Total operative time and room time was significantly longer for robotic surgery; however, estimated blood loss, the percentage of patients receiving transfusion, hospital length of stay, wound complications (4.1% vs. 20.2%, p=0.002) and other complications (9.6% vs. 29.8%, p=0.001) were improved for the robotic cohort. CONCLUSIONS: Robotic management of obese women with endometrial cancer yields acceptable staging results and improved surgical outcomes. Although operating time is longer, hospital time is shorter. Robotic surgery may be an ideal approach for these patients.

Testing and validation of a low-cost cystoscopy teaching model: a randomized controlled trial.

OBJECTIVE: To estimate whether the use of a low-cost cystoscopy model effectively trains residents in cystourethroscopy and to validate the model as a teaching tool. METHODS: A randomized, controlled, and evaluator-blinded study was performed. Twenty-nine obstetrician-gynecologist residents had access to fresh-frozen cadavers on which baseline cystoscopic skills were assessed using the validated Objective Structured Assessment of Technical Skills checklists for cystourethroscopy. Subsequently, residents were randomized to one of two arms, a didactic study arm using the cystoscopy model and a control arm. Repeated technical skills testing was performed. RESULTS: The study group demonstrated statistically significant decreases in cystoscope assembly time (128.8 seconds at baseline to 54.9 seconds postintervention; P=.005), and increases in task-specific checklist scores (from 59.3 at baseline to 92.9 postintervention; P<.001) and in global rating scale scores (from 61.0 at baseline to 87.8 postintervention; P<.001). Further, there was a significant improvement in task-specific checklist (P<.001), global rating scale (P=.002), and knowledge quiz scores (P=.011) in the study arm compared with the control arm. CONCLUSION: Use of the bladder model exhibited validity in enhancing performance and knowledge of cystourethroscopy among ob-gyn residents. LEVEL OF EVIDENCE: I.

Comprehensive surgical staging for endometrial cancer in obese patients: comparing robotics and laparotomy.

OBJECTIVE: To compare adequacy and outcomes of surgical staging for endometrial cancer in obese women by robotics or laparotomy. METHODS: Clinical stage I or occult stage II endometrial cancer patients with body mass indexes (BMIs) of at least 30 (BMI is calculated as weight (kg)/[height (m)]2) were identified undergoing robotic staging and matched 1:2 with laparotomy patients. Patient characteristics, operative times, complications, and pathologic factors were collected. An adequate lymphadenectomy was defined arbitrarily as at least 10 total nodes removed, and adequate pelvic and paraaortic lymphadenectomy was defined as at least six and at least four nodes removed, respectively. RESULTS: A total of 109 patients underwent surgery with the intent of robotic staging and were matched to 191 laparotomy patients. The mean BMI was 40 for each group. The robotic conversion rate was 15.6% (95% confidence interval [CI] 9.5-24.2%). Ninety-two completed robotic patients were compared with 162 matched laparotomy patients. The two groups were comparable regarding total lymph node count (25 +/- compared with 24 +/- 12, P =.45) and the percentage of patients undergoing adequate lymphadenectomy (85% compared with 91%, P=.16) and adequate pelvic (90% compared with 95%, P=.16) and aortic lymphadenectomy (76% compared with 79%, P=.70) for robotic and laparotomy patients, respectively, but there was limited power to detect this difference. The blood transfusion rate (2% compared with 9%, odds ratio [OR] 0.22, 95% CI 0.05-0.97, P=.046), the number of nights in the hospital (1 compared with 3, P<.001), complications (11% compared with 27%, OR 0.29, 95% CI 0.13-0.65 P=.003), and wound problems (2% compared with 17%, OR 0.10, 95% CI 0.02-0.43, P=.002) were reduced for robotic surgery. CONCLUSION: In obese women with endometrial cancer, robotic comprehensive surgical staging is feasible. Importantly, obesity may not compromise the ability to adequately stage patients robotically. LEVEL OF EVIDENCE: II

Abnormal white matter in a neurologically intact child with incontinentia pigmenti.

Incontinentia pigmenti is an X-linked neurocutaneous disorder which is often lethal in males. Ectodermal tissues are involved, and affected females often have abnormalities of skin, teeth, hair, eyes, and the central nervous system. Central nervous system involvement ranges from none to multiple strokes, seizures, and mental retardation. Deletions in the nuclear factor kappa beta essential modulator gene at Xq28 are present in 70-80% of patients with incontinentia pigmenti. White matter abnormalities have been reported in females with significant neurologic involvement. This report describes a neurologically intact child with deletion positive incontinentia pigmenti with significant white matter involvement, broadening the scope of this finding in incontinentia pigmenti.

Community response to disaster: the role of the workplace.

Disasters, natural and man-made, have a considerable impact on communities. Most recently, disasters stemming from terrorist attacks have become a leading cause of concern. The importance of work in the lives of employees, coupled with the vulnerability of workplaces as potential targets of terrorist attacks, suggests that workplaces can and should play a role in planning for, and responding to, disasters. This article addresses the role of the workplace in disasters, with an emphasis on the psychological impact of such events, by drawing upon experience and literature related to workplace violence and to other traumatic events in the workplace.