Mechanisms of action and resistance in histone methylation-targeted therapy.

Epigenomes enable the rectification of disordered cancer gene expression, thereby providing new targets for pharmacological interventions. The clinical utility of targeting histone H3 lysine trimethylation (H3K27me3) as an epigenetic hallmark has been demonstrated1-7. However, in actual therapeutic settings, the mechanism by which H3K27me3-targeting therapies exert their effects and the response of tumour cells remain unclear. Here we show the potency and mechanisms of action and resistance of the EZH1-EZH2 dual inhibitor valemetostat in clinical trials of patients with adult T cell leukaemia/lymphoma. Administration of valemetostat reduced tumour size and demonstrated durable clinical response in aggressive lymphomas with multiple genetic mutations. Integrative single-cell analyses showed that valemetostat abolishes the highly condensed chromatin structure formed by the plastic H3K27me3 and neutralizes multiple gene loci, including tumour suppressor genes. Nevertheless, subsequent long-term treatment encounters the emergence of resistant clones with reconstructed aggregate chromatin that closely resemble the pre-dose state. Acquired mutations at the PRC2-compound interface result in the propagation of clones with increased H3K27me3 expression. In patients free of PRC2 mutations, TET2 mutation or elevated DNMT3A expression causes similar chromatin recondensation through de novo DNA methylation in the H3K27me3-associated regions. We identified subpopulations with distinct metabolic and gene translation characteristics implicated in primary susceptibility until the acquisition of the heritable (epi)mutations. Targeting epigenetic drivers and chromatin homeostasis may provide opportunities for further sustained epigenetic cancer therapies.

Strangulated bowel obstruction caused by an ileo-ileal knot: a rare case report.

BACKGROUND: Intestinal knot formation is a condition wherein two segments of the intestine are knotted together; however, reports of small-intestinal ileo-ileal knot formation are rare. CASE PRESENTATION: The patient was a 62-year-old Asian male with a history of endoscopic colorectal adenoma resection and a spontaneous pneumothorax. The patient had no history of a laparotomy. He consulted his local doctor with the chief complaint of abdominal pain and was admitted to our hospital with suspicion of an acute abdomen. The abdomen had muscular guarding with tenderness and rebound tenderness. Contrast-enhanced computed tomography (CT) showed torsion of the mesentery of the small intestine with poor contrast filling. The patient was referred to our department with strangulated bowel obstruction and underwent an emergency laparotomy. Intraoperative findings revealed that two segments of the ileum were wrapped around each other to form a knot, and the strangulated small bowel was necrotic. After the release of the knot, partial resection of the small intestine was performed from 220 cm distal to the ligament of Treitz to 80 cm proximal to the cecum. The patient had a good postoperative course and was discharged on the 11th postoperative day. CONCLUSION: Ileo-ileal knots should be considered as part of the differential diagnosis when treating strangulated bowel obstruction.

A novel Menin-MLL1 inhibitor, DS-1594a, prevents the progression of acute leukemia with rearranged MLL1 or mutated NPM1.

BACKGROUND: Mixed lineage leukemia 1-rearranged (MLL1-r) acute leukemia patients respond poorly to currently available treatments and there is a need to develop more effective therapies directly disrupting the Menin‒MLL1 complex. Small-molecule-mediated inhibition of the protein‒protein interaction between Menin and MLL1 fusion proteins is a potential therapeutic strategy for patients with MLL1-r or mutated-nucleophosmin 1 (NPM1c) acute leukemia. In this study, we preclinically evaluated the new compound DS-1594a and its salts. METHODS: We evaluated the preclinical efficacy of DS-1594a as well as DS-1594a·HCl (the HCl salt of DS-1594a) and DS-1594a·succinate (the succinic acid salt of DS-1594a, DS-1594b) in vitro and in vivo using acute myeloid leukemia (AML)/acute lymphoblastic leukemia (ALL) models. RESULTS: Our results showed that MLL1-r or NPM1c human leukemic cell lines were selectively and highly sensitive to DS-1594a·HCl, with 50% growth inhibition values < 30 nM. Compared with cytrabine, the standard chemotherapy drug as AML therapy, both DS-1594a·HCl and DS-1594a·succinate mediated the eradication of potential leukemia-initiating cells by enhancing differentiation and reducing serial colony-forming potential in MLL1-r AML cells in vitro. The results were confirmed by flow cytometry, RNA sequencing, RT‒qPCR and chromatin immunoprecipitation sequencing analyses. DS-1594a·HCl and DS-1594a·succinate exhibited significant antitumor efficacy and survival benefit in MOLM-13 cell and patient-derived xenograft models of MLL1-r or NPM1c acute leukemia in vivo. CONCLUSION: We have generated a novel, potent, orally available small-molecule inhibitor of the Menin-MLL1 interaction, DS-1594a. Our results suggest that DS-1594a has medicinal properties distinct from those of cytarabine and that DS-1594a has the potential to be a new anticancer therapy and support oral dosing regimen for clinical studies (NCT04752163).

[A Case of Double Cancer of Squamous Cell Carcinoma of the Rectum and Adenocarcinoma of the Sigmoid Colon].

A 72-year-old male was transported to our hospital with complaints of heart palpitations and dyspnea since a month earlier and was immobile. Blood examination showed severe anemia, and colonoscopy revealed circumferential tumors in the rectum and the sigmoid colon. Histopathologic examination revealed the tumors as squamous cell carcinoma of the rectum and adenocarcinoma of the sigmoid colon. Therefore, they were diagnosed as double colorectal cancers. CT and MRI showed that rectal cancer invaded the seminal vesicles and the prostate; therefore, the patient underwent neoadjuvant chemoradiotherapy(oral capecitabine and concomitant radiation therapy: a total dose of 50.4 Gy/28 Fr)followed by total pelvic exenteration. Subsequent specimen pathology revealed a tumor regression grading of Grade 2 for the rectal and sigmoid colon cancers, and both were staged as ypT3N0M0, ypStage Ⅱa. Herein, we report a rare case of double cancer of adenocarcinoma of the sigmoid colon and squamous cell carcinoma of the rectum with a literature review.

Potent and Selective PTDSS1 Inhibitors Induce Collateral Lethality in Cancers with PTDSS2 Deletion.

SIGNIFICANCE: This study identifies a specific dependency on PTDSS1 for phosphatidylserine synthesis following PTDSS2 deletion and introduces novel PTDSS1 inhibitors as a therapeutic option to induce collateral lethality in cancer with PTDSS2 loss.

Clinical usefulness of 2-hydroxyglutarate as a biomarker in IDH-mutant chondrosarcoma.

Background: Chondrosarcoma is a common form of malignant bone tumor with limited treatment options. Approximately half of chondrosarcomas harbor gain-of-function mutations in isocitrate dehydrogenase (IDH), and mutant IDH produces 2-hydroxyglutarate (2-HG), which is an oncometabolite that contributes to malignant transformation. Therefore, inhibiting 2-HG production is a novel and promising treatment for advanced chondrosarcoma. 2-HG is also expected to be a useful biomarker for the diagnosis and treatment of IDH-mutant tumors. However, few studies have confirmed this using chondrosarcoma clinical specimens. Non-invasive monitoring of 2-HG levels is useful to infer that mutant IDH inhibitors reach therapeutic targets and to confirm their therapeutic efficacy in clinical practice. Methods: To evaluate the clinical utility of 2-HG as a surrogate biomarker for diagnosis and therapeutic efficacy, we measured intra-tumor and serum levels of 2-HG using frozen tissues and peripheral blood from patients with chondrosarcoma. We also developed a non-invasive method to detect intra-tumor 2-HG signals in vivo using magnetic resonance spectroscopy (MRS). Results: Both intratumoral and serum 2-HG levels were significantly elevated in IDH-mutant tumors, and these levels correlated with decreased survival. Furthermore, we detected intratumoral 2-HG peaks using MR spectroscopy in a xenograft model of IDH-mutant chondrosarcoma, and observed that 2-HG peak signals disappeared after administering an inhibitor of mutant IDH1. Conclusions: Our findings suggest that both intratumoral and serum 2-HG levels represent potentially useful biomarkers for IDH-mutant tumors and that the 2-HG signal in MR spectra has potential value as a non-invasive biomarker. Taken together, these findings may positively impact the clinical development of mutant IDH inhibitors for the treatment of advanced chondrosarcoma.

A Prospective Multicenter Phase II Study on the Feasibility and Efficacy of S-1 and Oxaliplatin Neoadjuvant Chemotherapy for Locally Advanced Rectal Cancer.

BACKGROUND: Neoadjuvant chemoradiotherapy and total mesorectal excision compose the standard of care for rectal cancer in multiple guidelines. However, neoadjuvant chemoradiotherapy has not exhibited clear survival benefits but rather has led to an increase in adverse events. Conversely, neoadjuvant chemotherapy is expected to prevent adverse events caused by radiation, yet this treatment is still controversial. OBJECTIVE: The purpose of this study was to evaluate the feasibility and efficacy of S-1 and oxaliplatin neoadjuvant chemotherapy together with total mesorectal excision for resectable locally advanced rectal cancer. DESIGN: The study was a prospective, single-arm phase II trial. SETTINGS: The study was conducted at multiple institutions. PATIENTS: Fifty-eight patients with resectable locally advanced rectal cancer were enrolled. INTERVENTION: Three cycles of S-1 and oxaliplatin were administered before surgery. S-1 was administered orally at 80 mg/m2 per day for 14 consecutive days, followed by a 7-day resting period. Oxaliplatin was given intravenously on the first day at a dose of 130 mg/m2 per day. The duration of 1 cycle was considered to be 21 days. Total mesorectal excision with bilateral lymph node dissection was carried out after neoadjuvant chemotherapy. MAIN OUTCOME MEASURES: The study was designed to detect the feasibility and efficacy of S-1 and oxaliplatin as neoadjuvant chemotherapy. RESULTS: The completion rate of 3 courses of S-1 and oxaliplatin as neoadjuvant chemotherapy was 94.8% (55/58). The reasons for discontinuation were thrombocytopenia (3.4%) and liver injury (1.7%). The most common severe (grade ≥3) adverse effect of neoadjuvant chemotherapy was thrombocytopenia (3.4%). There were no severe adverse clinical symptoms. Consequently, R0 resection was achieved in 51 (98.1%) of 52 patients. Pathologic complete response occurred in 10 patients (19.2%). LIMITATIONS: This was a single-arm, nonrandomized phase II study. CONCLUSIONS: The combination of S-1 and oxaliplatin neoadjuvant chemotherapy and total mesorectal excision is a feasible and promising treatment option for resectable locally advanced rectal cancer. See Video Abstract at http://links.lww.com/DCR/B555. UN ESTUDIO PROSPECTIVO MULTICNTRICO FASE II SOBRE LA FACTIBILIDAD Y EFICACIA DE LA QUIMIOTERAPIA NEOADYUVANTE SCON OXALIPLATINO PARA EL CNCER DE RECTO LOCALMENTE AVANZADO: ANTECEDENTES:La quimiorradioterapia neoadyuvante y la escisión mesorrectal total constituyen el estándar de atención para el cáncer de recto en varias guías. Sin embargo, la quimiorradioterapia neoadyuvante no ha mostrado beneficios claros en la sobrevida, pero si ha creado un aumento de eventos adversos. Por otro lado, se espera que la quimioterapia neoadyuvante prevenga los eventos adversos asociados a la radiación, aunque este tratamiento sigue siendo controvertido.OBJETIVO:Evaluar la factibilidad y eficacia de la quimioterapia neoadyuvante S-1 con oxaliplatino en conjunto con la escisión mesorrectal total para el cáncer de recto localmente avanzado resecable.DISEÑO:El estudio fue un ensayo prospectivo fase II de brazo único.AMBITO:Estudio realizado en múltiples instituciones.PACIENTES:Se incluyeron 58 pacientes con cáncer de recto localmente avanzado resecable.INTERVENCIÓN:Se administraron tres ciclos de S-1 con oxaliplatino antes de la cirugía. Se administró S-1 por vía oral a 80 mg / m2 / día durante 14 días consecutivos, seguido de un período de descanso de 7 días. El oxaliplatino se administró por vía intravenosa el primer día a una dosis de 130 mg / m2 / día. Se consideró la duración de un ciclo de 21 días. Posterior a la quimioterapia neoadyuvante se realizó la excisión total mesorrectal con disección ganglionar bilateral.PRINCIPALES VARIABLES EVALUDADAS:El estudio fue diseñado para conocer la factibilidad y eficacia de S-1 con oxaliplatino como quimioterapia neoadyuvante.RESULTADOS:La tasa de conclusión con tres ciclos de S-1 con oxaliplatino como quimioterapia neoadyuvante fue del 94,8% (55/58). Los motivos de interrupción fueron trombocitopenia (3,4%) y daño hepático (1,7%). El efecto adverso grave más común (grado ≥ 3) de la quimioterapia neoadyuvante fue la trombocitopenia (3,4%). No hubo síntomas clínicos adversos graves. Como resultado, la resección R0 se logró en 51 de 52 pacientes (98,1%). Una respuesta patológica completa se obtuvo en 10 pacientes (19,2%).LIMITACIONES:Fue un estudio de fase II no aleatorizado de un solo brazo.CONCLUSIONES:La combinación de S-1 con oxaliplatino como quimioterapia neoadyuvante y escisión mesorrectal total es factible y es una opción de tratamiento prometedora para el cáncer de recto localmente avanzado resecable. Consulte Video Resumen en http://links.lww.com/DCR/B555. (Traducción-Dr Juan Antonio Villanueva-Herrero).

Discovery of a Potent, Selective, and Orally Available MTHFD2 Inhibitor (DS18561882) with in Vivo Antitumor Activity.

We report the discovery of a potent and isozyme-selective MTHFD2 inhibitor, DS18561882 (2). Through investigation of the substituents on our tricyclic coumarin scaffold (1,2,3,4-tetrahydrochromeno[3,4-c]pyridin-5-one), MTHFD2 inhibitory activity was shown to be elevated by incorporating an amine moiety at the 8-position and a methyl group at the 7-position of the initial lead 1. X-ray structure analysis revealed that a key interaction for enhanced potency was salt bridge formation between the amine moiety and the diphosphate linker of an NAD+ cofactor. Furthermore, ortho-substituted sulfonamide in place of benzoic acid of 1 significantly improved cell permeability and cell-based growth inhibition against a human breast cancer cell line. The thus-optimized DS18561882 showed the strongest cell-based activity (GI50 = 140 nM) in the class, a good oral pharmacokinetic profile, and thereby tumor growth inhibition in a mouse xenograft model upon oral administration.

Smoking cessation contributes to weight gain in patients with hepatobiliopancreatic malignancy.

BACKGROUND & AIMS: The relationship between smoking cessation and weight gain is well recognized. However, there is no data currently available on the effect of smoking cessation on weight gain in patients with malignancy. The aim of this study was to clarify the body weight (BW) change after smoking cessation in patients with malignancy. METHODS: We retrospectively analyzed 159 subjects who underwent hepatobiliopancreatic surgery. The smoking status was determined using questionnaires administered at the initial presentation, and the candidates were divided into two groups: recent quitters and nonsmokers. The change in the BW was compared between these two groups. RESULTS: There were 134 subjects with malignant disease (84.3%), with a median age of 68 (range: 26-84) years. In the nonsmoker group, 28 of 116 subjects (24.1%) gained weight between the initial presentation and admission. In the recent quitter group, 12 of 18 subjects (66.7%) gained weight in the same period (P < 0.01). Regarding the change in the BW from the initial presentation, recent quitters gained more weight than nonsmokers (+1.7 kg [+2.7%] vs. -1.0 kg [-2.0%], P < 0.01). Furthermore, the improvement from the initial presentation was seen in a higher percentage of recent quitters than nonsmokers with respect to Onodera's prognostic nutritional index (61.1% vs. 36.2%, P = 0.04) and the controlling nutritional status score (38.9% vs. 19.3%, P = 0.07). CONCLUSIONS: Weight gain due to smoking cessation was observed even in patients with hepatobiliopancreatic malignancy.

[A Case of Laparoscopic Low Anterior Resection and Adrenalectomy for Rectal Cancer and Adrenal Tumor].

A 70-year-old woman had consulted a doctor at a former clinic because of bloody stool and colonoscopy revealed a type 2 tumor of the rectum. She was referred to our hospital for further examinations and treatment. Preoperative blood examination showed an elevated HbA1c level of 10.2%. Abdominal CT showed a 25mm tumor in the left adrenal gland. The patient was diagnosed with adrenal Cushing's syndrome based on low ACTH levels, disappearance of circadian variation in blood cortisol levels, lack of inhibition by dexamethasone loading, and high urinary cortisol levels. Laparoscopic adrenalectomy for left adrenal tumor and low anterior resection for rectal cancer were performed. The pathological findings were rectal cancer, pap, pT1b(SM), pN0, cM0, fStageⅠof rectal cancer, and adrenal cortical adenoma. The postoperative course was uneventful with steroid replacement therapy. The ileal stoma was closed 4 months after surgery. Surgery in hyperadrenalism requires perioperative steroid replacement therapy because of the risk of postoperative acute adrenal failure. In addition, when diabetes is poorly controlled, we should be careful about risk of leakage and susceptibility to infection.

Living donor liver transplantation in a pediatric patient with preexisting yolk sac tumor.

There is ongoing discussion regarding the indications and timing of LT for patients with a preexisting extrahepatic malignancy. We herein report a pediatric case that underwent LDLT after therapy for YST. The patient, a 13-year-old female with biliary atresia, had undergone portoenterostomy at 2 months of age. She developed a left ovarian tumor with a high serum alpha-fetoprotein concentration at 10 years of age. She underwent left oophorectomy and was diagnosed with ovarian YST (Stage I). After surgery, hepatopulmonary syndrome progressed gradually. She was examined carefully and exhibited no findings to suggest the recurrence of YST. We decided to perform LDLT at 3 years and 6 months of age after the surgery for YST. The patient is currently alive and doing well without recurrence of YST at approximately 2 years after transplantation. There is no significant difference between the recurrence rate of preexisting extrahepatic malignancy and the incidence of de novo malignancy if specific cases are selected. The indications and period from surgery for preexisting extrahepatic malignancy to LT should thus be determined according to the type and stage of cancer.

[A Case of Appendiceal Mucinous Adenocarcinoma Detected with a Bladder Tumor].

A 74-year-oldwoman hadconsultedthe department of urology in our hospital because of microscopic hematuria. Cystoscopy revealeda urinary bladder tumor, suspectedas an adenocarcinoma basedon biopsy. MRI showeda cystic tumor of the appendix with vesical fistula; therefore, she underwent an operation with a diagnosis of appendiceal cancer invading the urinary bladder. During the operation, we found that the appendix sunk into the urinary bladder with right adnexa. Therefore, we performed ileocecal resection, partial resection of the urinary bladder, and right adnexectomy. Macroscopically, the bladder was filled with a large number of mucus lumps. A papillary tumor, 4 cm in size, growing in the lumen of the bladder was detectedat the invasion site. Microscopically, proliferating carcinoma cells in a papillary form were observedin the lumen of the appendix with mucus production, invading the wall of the urinary bladder at the fundus of the appendix. Thus, the patient was diagnosed with mucinous adenocarcinoma of the appendix(V, type 1, 45×30 mm, muc, pT4b[SI, urinary bladder], int, INF c, ly0, v0, pN0, cM0, pStage II ). Primary appendiceal cancer invading the urinary bladder is very rare; herein, we report a rare case of appendiceal mucinous adenocarcinoma detected with a bladder tumor and present a literature review.

[A Case of Effective Neoadjuvant Chemotherapy for Transverse Colon Cancer with Extensive Abdominal Wall Invasion].

A 68-year-old man with abdominal mass and anorexia was diagnosed with transvers colon cancer invading the abdominal wall. Considering the difficulty of curative resection, we first performed ileostomy. After surgery, the patient received mFOL FOX6 with bevacizumab as neoadjuvant chemotherapy. After 10 course of the regimen, computed tomography revealed shrinkage of the lesion, with the efficacy evaluated as a partial response. The patient underwent right hemicolectomy and partial resection of the abdominal wall. The pathological findings was ypT3(SS), ypN3, ly0, v1, ypPM0, ypDM0, ypRM0, ypStage III b. On histopathological examination, the efficacy of the chemotherapy was evaluated as Grade 1b. The patient received adjuvant chemotherapy with mFOLFOX6 and remains well without any evidence of recurrence more than 7 months after surgery.

Streptococcal Toxic Shock Syndrome: Life Saving Role of Peritoneal Lavage and Drainage.

PURPOSE: We encountered a case where an infection with group A streptococcus (GAS; ie, Streptococcus pyogenes) initially caused primary peritonitis and then subsequently caused streptococcal toxic shock syndrome. The patient's life was likely saved by an emergency laparotomy followed by extensive peritoneal lavage and drainage. CASE PRESENTATION: A 40-year-old woman was admitted to the Emergency Department for lower abdominal pain and numbness in the extremities. She presented with systemic inflammatory response syndrome. An emergency laparotomy was performed, and ascites that resembled pus and general peritonitis were noted. Peritoneal lavage and drainage were performed, and GAS was isolated from peritoneal fluid. Gram staining of cervical polyp specimens revealed Gram-positive bacteria. CONCLUSIONS: The patient was diagnosed with streptococcal toxic shock syndrome due to an ascending GAS infection originating from vagina.

Mps1 Mediated Phosphorylation of Hsp90 Confers Renal Cell Carcinoma Sensitivity and Selectivity to Hsp90 Inhibitors.

The molecular chaperone Hsp90 protects deregulated signaling proteins that are vital for tumor growth and survival. Tumors generally display sensitivity and selectivity toward Hsp90 inhibitors; however, the molecular mechanism underlying this phenotype remains undefined. We report that the mitotic checkpoint kinase Mps1 phosphorylates a conserved threonine residue in the amino-domain of Hsp90. This, in turn, regulates chaperone function by reducing Hsp90 ATPase activity while fostering Hsp90 association with kinase clients, including Mps1. Phosphorylation of Hsp90 is also essential for the mitotic checkpoint because it confers Mps1 stability and activity. We identified Cdc14 as the phosphatase that dephosphorylates Hsp90 and disrupts its interaction with Mps1. This causes Mps1 degradation, thus providing a mechanism for its inactivation. Finally, Hsp90 phosphorylation sensitizes cells to its inhibitors, and elevated Mps1 levels confer renal cell carcinoma selectivity to Hsp90 drugs. Mps1 expression level can potentially serve as a predictive indicator of tumor response to Hsp90 inhibitors.

[A Case of Primary Sclerosing Cholangitis Difficult to Distinguish from a Hilar Cholangiocarcinoma].

A 78-year-old man, who had presented with onset of ulcerative colitis at the age of 56 years and had been in remission for the past several years, attended our hospital with a diagnosis of obstructive jaundice. A hilar cholangiocarcinoma with right hepatic artery invasion was suspected on contrast enhanced CT. An endoscopic retrograde cholangiography indicated Bismuth type 2 stenosis. The stenotic bile duct brushings revealed no malignancy. Primary sclerosing cholangitis(PSC)and IgG4- related cholangitis were included in the differential diagnosis; however, a significant result could not be obtained in any other examinations. A hilar cholangiocarcinoma could not be ruled out, and rt. hepatic lobectomy and caudate lobectomy with resection of the extrahepatic bile duct were performed after obtaining informed consent. The histopathological findings revealed no atypical cells in the stenotic lesion, but fibrosis and inflammatory cell infiltration were observed around the bile duct. These findings were consistent with PSC. On the other hand, atypical cell proliferation with lymph duct infiltration was found in the mucosa of the gall bladder. It is difficult to preoperatively diagnose PSC localized to the hilar bile duct, and if possible, the existence of concomitant malignant lesions in the biliary tract should be considered.

Client Proteins and Small Molecule Inhibitors Display Distinct Binding Preferences for Constitutive and Stress-Induced HSP90 Isoforms and Their Conformationally Restricted Mutants.

The two cytosolic/nuclear isoforms of the molecular chaperone HSP90, stress-inducible HSP90α and constitutively expressed HSP90ß, fold, assemble and maintain the three-dimensional structure of numerous client proteins. Because many HSP90 clients are important in cancer, several HSP90 inhibitors have been evaluated in the clinic. However, little is known concerning possible unique isoform or conformational preferences of either individual HSP90 clients or inhibitors. In this report, we compare the relative interaction strength of both HSP90α and HSP90ß with the transcription factors HSF1 and HIF1α, the kinases ERBB2 and MET, the E3-ubiquitin ligases KEAP1 and RHOBTB2, and the HSP90 inhibitors geldanamycin and ganetespib. We observed unexpected differences in relative client and drug preferences for the two HSP90 isoforms, with HSP90α binding each client protein with greater apparent affinity compared to HSP90ß, while HSP90ß bound each inhibitor with greater relative interaction strength compared to HSP90α. Stable HSP90 interaction was associated with reduced client activity. Using a defined set of HSP90 conformational mutants, we found that some clients interact strongly with a single, ATP-stabilized HSP90 conformation, only transiently populated during the dynamic HSP90 chaperone cycle, while other clients interact equally with multiple HSP90 conformations. These data suggest different functional requirements among HSP90 clientele that, for some clients, are likely to be ATP-independent. Lastly, the two inhibitors examined, although sharing the same binding site, were differentially able to access distinct HSP90 conformational states.

Perioperative blood transfusion as a poor prognostic factor after aggressive surgical resection for hilar cholangiocarcinoma.

BACKGROUND: Blood transfusion is linked to a negative outcome for malignant tumors. The aim of this study was to evaluate aggressive surgical resection for hilar cholangiocarcinoma (HCCA) and assess the impact of perioperative blood transfusion on long-term survival. METHODS: Sixty-six consecutive major hepatectomies with en bloc resection of the caudate lobe and extrahepatic bile duct for HCCA were performed using macroscopically curative resection at our institute from 2002 to 2012. Clinicopathologic factors for recurrence and survival were retrospectively assessed. RESULTS: Overall survival rates at 1, 3, and 5 years were 86.7, 47.3, and 35.7 %, respectively. In univariate analysis, perioperative blood transfusion and a histological positive margin were two of several variables found to be significant prognostic factors for recurrence or survival (P<0.05). In multivariate analysis, only perioperative blood transfusion was independently associated with recurrence (hazard ratio (HR)=2.839 (95 % confidence interval (CI), 1.370-5.884), P=0.005), while perioperative blood transfusion (HR=3.383 (95 % CI, 1.499-7.637), P=0.003) and R1 resection (HR=3.125 (95 % CI, 1.025-9.530), P=0.045) were independent risk factors for poor survival. CONCLUSIONS: Perioperative blood transfusion is a strong predictor of poor survival after radical hepatectomy for HCCA. We suggest that circumvention of perioperative blood transfusion can play an important role in long-term survival for patients with HCCA.

Asymmetric Hsp90 N domain SUMOylation recruits Aha1 and ATP-competitive inhibitors.

The stability and activity of numerous signaling proteins in both normal and cancer cells depends on the dimeric molecular chaperone heat shock protein 90 (Hsp90). Hsp90's function is coupled to ATP binding and hydrolysis and requires a series of conformational changes that are regulated by cochaperones and numerous posttranslational modifications (PTMs). SUMOylation is one of the least-understood Hsp90 PTMs. Here, we show that asymmetric SUMOylation of a conserved lysine residue in the N domain of both yeast (K178) and human (K191) Hsp90 facilitates both recruitment of the adenosine triphosphatase (ATPase)-activating cochaperone Aha1 and, unexpectedly, the binding of Hsp90 inhibitors, suggesting that these drugs associate preferentially with Hsp90 proteins that are actively engaged in the chaperone cycle. Importantly, cellular transformation is accompanied by elevated steady-state N domain SUMOylation, and increased Hsp90 SUMOylation sensitizes yeast and mammalian cells to Hsp90 inhibitors, providing a mechanism to explain the sensitivity of cancer cells to these drugs.