Oral arsenic plus imatinib versus imatinib solely for newly diagnosed chronic myeloid leukemia: a randomized phase 3 trial with 5-year outcomes

PURPOSE

The synergistic effects of combining arsenic compounds with imatinib against chronic myeloid leukemia (CML) have been established using in vitro data. We conducted a clinical trial to compare the efficacy of the arsenic realgar-indigo naturalis formula (RIF) plus imatinib with that of imatinib monotherapy in patients with newly diagnosed chronic phase CML (CP-CML).

METHODS

In this multicenter, randomized, double-blind, phase 3 trial, 191 outpatients with newly diagnosed CP-CML were randomly assigned to receive oral RIF plus imatinib (n = 96) or placebo plus imatinib (n = 95). The primary end point was the major molecular response (MMR) at 6 months. Secondary end points include molecular response 4 (MR4), molecular response 4.5 (MR4.5), progression-free survival (PFS), overall survival (OS), and adverse events.

RESULTS

The median follow-up duration was 51 months. Due to the COVID-19 pandemic, the recruitment to this study had to be terminated early, on May 28, 2020. The rates of MMR had no significant statistical difference between combination and imatinib arms at 6 months and any other time during the trial. MR4 rates were similar in both arms. However, the 12-month cumulative rates of MR4.5 in the combination and imatinib arms were 20.8% and 10.5%, respectively (p = 0.043). In core treatment since the 2-year analysis, the frequency of MR4.5 was 55.6% in the combination arm and 38.6% in the imatinib arm (p = 0.063). PFS and OS were similar at five years. The safety profiles were similar and serious adverse events were uncommon in both groups.

CONCLUSION

The results of imatinib plus RIF as a first-line treatment of CP-CML compared with imatinib might be more effective for achieving a deeper molecular response (Chinadrugtrials number, CTR20170221).

[Consensus of experts on the medical risk prevention for the patients with cardiovascular diseases during dental treatment (2022 edition)]

With the aging process of population in the society, the prevalence of cardiovascular diseases (CVD) in China is increasing continuously and the number of dental patients with CVD is increasing gradually too. Due to the lack of guidelines for dental patients with CVD in our country, how to implement standardized preoperative evaluation and perioperative risk prevention remains a problem to be solved for dentists at present. The present expert consensus was reached by combining the clinical experiences of the expert group of the Fifth General Dentistry Special Committee, Chinese Stomatological Association and respiratory and cardiology experts in diagnosis and treatment for CVD patients, and by systematically summarizing the relevant international guidelines and literature regarding the relationship between CVD and oral diseases and the diagnosis and treatment of dental patients with heart failure, hypertension and antithrombotic therapy. The consensus aims to provide, for the dental clinicians, the criteria on diagnosis and treatment of CVD in dental patients in China so as to reduce the risk and complications, and finally to improve the treatment levels of dental patients with CVD in China.

[Efficacy and safety of alirocumab versus ezetimibe in high cardiovascular risk Chinese patients with hyperlipidemia: ODYSSEY EAST Study-Chinese sub-population analysis]

Objective: To compare the efficacy and safety profile of alirocumab (PCSK9 inhibitor) versus ezetimibe on top of maximally tolerated statin dose in high cardiovascular risk Chinese patients with hyperlipidemia. Methods: The ODYSSEY EAST study was a randomized, double-blinded, double dummy, active-control, parallel group, multi-centers clinical trial, the Chinese sub-population included 456 patients with hyperlipidemia and high cardiovascular risk on maximally tolerated statin dose. Patients were randomized (2∶1) to receive the subcutaneous injection of alirocumab (75 mg Q2W; with dose up titration to 150 mg Q2W at week 12 if low-density lipoprotein cholesterol (LDL-C) was ≥1.81 mmol/L at week 8) or the oral administration of ezetimibe (10 mg daily) for 24 weeks. The primary endpoint was percentage change in calculated LDL-C from baseline to week 24. Key secondary efficacy endpoints included percentage change from baseline to week 12 or 24 in LDL-C (week 12) and other lipid parameters, including apolipoprotein (Apo) B, non-high-density lipoprotein cholesterol (non-HDL-C), TC, lipoprotein(a) (Lp(a)), HDL-C, fasting triglycerides (TG), and Apo A1, and the proportion of patients reaching LDL-C<1.81 mmol/L at week 24. Safety profile of therapeutic drugs was also assessed during the treatment period. Results: The mean age of 456 Chinese patients was (59.5±10.9) years, 341(74.8%) patients were male, 303 patients (66.4%) in alirocumab group and 153 patients (33.5%) in ezetimibe group. Demographic characteristics, disease characteristics, and lipid parameters at baseline were similar between the two groups. LDL-C was reduced more from baseline to week 12 and 24 in alirocumab group versus ezetimibe group, the difference of their least-squares mean (standard error) percent change were(-35.2±2.2)% and (-36.9±2.5)% (both P<0.001). At 12 weeks, alirocumab had significant reduction on Lp(a), Apo B, total cholesterol and non HDL-C, the difference of their least-squares mean (standard error) percent change were (-40.3±2.8)%, (-27.7±1.8)%, (-19.6±1.5)% and (-27.7±1.9)%, respectively (all P<0.001). At 24 weeks, the percent of patients who reached LDL-C<1.81 mmol/L and LDL-C<1.42 mmol/L was significantly higher in alirocumab group (85.3% and 70.5%) than in ezetimibe group (42.2% and 17.0%, both P<0.001), and alirocumab use was also associated with significant reduction on Lp(a), Apo B, total cholesterol and non HDL-C, the difference of their least-squares mean (standard error) percent change were (-37.2±2.8)%, (-29.1±2.0)%, (-21.6±1.6)% and (-29.6±2.2)%, respectively (all P<0.001). The incidence of treatment related adverse events was similar between the two treatment groups (223/302 patients (73.8%) in alirocumab group and 109/153 patients (71.2%) in ezetimibe group). Respiratory infection, urinary infection, dizziness and local injection-site reactions were the most frequently reported adverse events. Conclusions: In high cardiovascular risk patients with hyperlipidemia from China on maximally tolerated statin dose, the reduction of LDL-C induced by alirocumab is more significant than that induced by ezetimibe. Both treatments were generally safe during the observation period of study.

[Inhibitors of RAS Might Be a Good Choice for the Therapy of COVID-19 Pneumonia]

The novel coronavirus 2019 (COVID-19) infected patients by binding human ACE2, leading to severe pneumonia and highly mortality rate in patients. At present, there is no definite and effective treatment for COVID-19. ACE2 plays an important role in the RAS, and the imbalance between ACE/Ang II/AT1R pathway and ACE2/Ang (1-7)/Mas receptor pathway in the RAS system will lead to multi-system inflammation. Increased ACE and Ang II are poor prognostic factors for severe pneumonia. Animal studies have shown that RAS inhibitors could effectively relieve symptoms of acute severe pneumonia and respiratory failure. The binding of COVID-19 and ACE2 resulted in the exhaustion of ACE2, and then ACE2/Ang (1-7)/Mas receptor pathway was inhibited. The balance of the RAS system was broken, and this would lead to the exacerbation of acute severe pneumonia. Therefore, we speculate that ACEI and AT1R inhibitors could be used in patients with COVID-19 pneumonia under the condition of controlling blood pressure, and might reduce the pulmonary inflammatory response and mortality.

[Inhibitors of RAS Might Be a Good Choice for the Therapy of COVID-19 Pneumonia]

The novel coronavirus 2019 (COVID-19) infected patients by binding human ACE2, leading to severe pneumonia and highly mortality rate in patients. At present, there is no definite and effective treatment for COVID-19. ACE2 plays an important role in the RAS, and the imbalance between ACE/Ang II/AT1R pathway and ACE2/Ang (1-7)/Mas receptor pathway in the RAS system will lead to multi-system inflammation. Increased ACE and Ang II are poor prognostic factors for severe pneumonia. Animal studies have shown that RAS inhibitors could effectively relieve symptoms of acute severe pneumonia and respiratory failure. The binding of COVID-19 and ACE2 resulted in the exhaustion of ACE2, and then ACE2/Ang (1-7)/Mas receptor pathway was inhibited. The balance of the RAS system was broken, and this would lead to the exacerbation of acute severe pneumonia. Therefore, we speculate that ACEI and AT1R inhibitors could be used in patients with COVID-19 pneumonia under the condition of controlling blood pressure, and might reduce the pulmonary inflammatory response and mortality.

Validation of a nomogram to predict the risk of cancer in patients with intraductal papillary mucinous neoplasm and main duct dilatation of 10 mm or less

BACKGROUND

Intraductal papillary mucinous neoplasm (IPMN) is premalignant pancreatic lesion. International guidelines offer limited predictors of individual risk. A nomogram to predict individual IPMN malignancy risk was released, with good diagnostic performance based on a large cohort of Asian patients with IPMN. The present study validated a nomogram to predict malignancy risk and invasiveness of IPMN using both Eastern and Western cohorts.

METHODS

Clinicopathological and radiological data from patients who underwent pancreatic resection for IPMN at four centres each in Eastern and Western countries were collected. After excluding patients with missing data for at least one malignancy predictor in the nomogram (main pancreatic duct diameter, cyst size, presence of mural nodule, serum carcinoembryonic antigen and carbohydrate antigen (CA) 19-9 levels, and age).

RESULTS

In total, data from 393 patients who fit the criteria were analysed, of whom 265 were from Eastern and 128 from Western institutions. Although mean age, sex, log value of serum CA19-9 level, tumour location, main duct diameter, cyst size and presence of mural nodule differed between the Korean/Japanese, Eastern and Western cohorts, rates of malignancy and invasive cancer did not differ significantly. Areas under the receiver operating characteristic (ROC) curve values for the nomogram predicting malignancy were 0·745 for Eastern, 0·856 for Western and 0·776 for combined cohorts; respective values for the nomogram predicting invasiveness were 0·736, 0·891 and 0·788.

CONCLUSIONS

External validation of the nomogram showed good performance in predicting cancer in both Eastern and Western patients with IPMN lesions.

Lowering hepatic venous pressure agent carvedilol versus variceal banding ligation for clinical outcomes of cirrhotic portal hypertension

OBJECTIVE

Carvedilol is nonselective beta-blocker with a mild anti-alpha-1-adrenergic effect. Several studies proposed improved hemodynamic effects of carvedilol compared with propanolol. Our study was to perform a systematic review and meta-analysis of randomized control trials comparing carvedilol with variceal banding ligation (VBL).

METHODS

Studies were searched on online databases MEDLINE, EMBASE(Ovid), the Cochrane Library, Chinese Wanfang Database, and China National Knowledge Infrastructure between January 2000 and May 2018. Incidence of bleeding and mortality were main outcome measures. Subgroup analysis and sensitivity analysis were conducted to ensure the robustness of pooled estimates.

RESULTS

Ten randomized control trials including 1,269 cirrhotic patients were chosen. Compared with VBL, carvedilol showed similar preventive efficacy of risk ratios (RRs) in variceal bleeding, and bleeding-related mortality over different follow-up periods from 6 months to 24 months. Also, significant differences between carvedilol and VBL in overall mortality and other causes of mortality were failed to be found. Carvedilol achieved a lower incidence of portal hypertension gastropathy in both 6 months (RR=0.49, 95% CI: 0.38-0.64, P<0.00001) and 12 months (RR=0.35, 95% CI: 0.26-0.47, P<0.00001). Two trials compared combination of carvedilol and VBL with VBL alone; however, the results failed to find an improved preventive efficacy of bleeding (RR=0.71, 95% CI: 0.15-3.30, P=0.67).

CONCLUSION

Carvedilol is equivalent to invasive VBL for variceal bleeding prevention. It can be well tolerated and may be of benefit to portal hypertension gastropathy. However, available data during 24 months follow-up did not support a potential advantage of carvedilol for prognosis as a lowering hepatic venous pressure agent.

[Randomized controlled trials of needle knife therapy combined with rotation traction manipulation for the treatment of cervical spondylotic radiculopathy]

OBJECTIVE

To compare the therapeutic effects between needle knife therapy combined with rotation traction manipulation and rotation traction manipulation for the treatment of cervical spondylotic radiculopathy.

METHODS

From November 2013 to June 2015, 80 patients with cervical spondylotic radiculopathy meeting the inclusion criteria were divided into two groups randomly:the control group in which 39 patients were treated with rotation traction manipulation, and the treatment group in which 41 patients were treated with needle knife combined with rotation traction manipulation. The patients in the control group were treated once dayly for 2 weeks, which was 1 course. The patients in the treatment group were treated with needle knife firstly once a week for 2 weeks, which was 1 course;then were treated with the same methods as the patients in the control group. The symptoms, signs score and the therapeutic effects of the two groups before and after treatment were observed.

RESULTS

After treatment, symptoms and signs scores declined in both groups(P<0.05). The results of the treatment group were better than effects in the control group(P<0.05). In the treatment group, 19 patients got an excellent result, 16 good, 5 fair and 1 bad;while in the control group, 10 patients got an excellent result, 10 good, 16 fair and 3 bad;the results of the treatment group were better than the results of the control group(P<0.01).

CONCLUSIONS

Needle knife combined with rotation traction manipulation is an effective method for the treatment of cervical spondylotic radiculopathy, which is better than using manipulation method simply. Needle knife therapy has follow advantages:improving local blood circulation, reducing local content of pain substance, increasing production of substances resisting pain, opening channels and collaterals, and make body reaching new static and dynamic balance on the new foundation.

Multiple myeloma with intracranial extension and bilateral renal infiltration: A case report and review of the literature

Multiple myeloma (MM) is a rare hematological malignancy, characterized by uncontrolled proliferation of plasma cells in the bone marrow. MM is usually confined to the bone marrow, however, it may occasionally infiltrate other tissues, which is known as extramedullary plasmacytoma (EMP). The majority of EMPs involve the head and neck region, although different anatomical sites, including the gastrointestinal tract, central nervous system, thyroid gland and breast may also be affected. The simultaneous presentation of EMP in the kidney and head is rare, presenting diagnostic challenges due to its unusual location and non-specific or absent symptoms. To the best of our knowledge, no case of extramedullary plasmacytoma presenting with simultaneous renal and intracranial infiltration has been reported in the literature thus far. However, the present study reports a case of primary renal and intracranial extramedullary plasmacytoma in a 76-year-old male patient. The patient presented with a swelling over the right side of the forehead, which had slowly increased in size prior to hospital admission. The swelling was associated with dizziness and weakness, without bone pain. Contrast magnetic resonance imaging suggested an osteolytic skull lesion with intracranial extension. Abdominal enhanced computed tomography scanning revealed a large tumor mass extending around and into the kidneys. Immunohistochemical examination of the renal tumor biopsy, and blood and serum samples, as well as immunoelectrophoresis of serum proteins, resulted in a diagnosis of EMP being proposed. Therefore, the patient was administered with two cycles of cyclophosphamide and thalidomide in combination with dexamethasone. Follow-up imaging performed 4 months later revealed almost complete disappearance of the intracranial tumor mass and renal infiltration. The current study also presented a review of the literature. This study revealed that EMPs may co-exist with MM or present as the main symptom of MM. The diagnosis of an EMP is complex and requires radiological, hematological, biochemical and histological investigation. At present, no guidelines for EMP treatment have been established and thus, treatment options include surgery, chemotherapy and radiotherapy, either alone or in combination. We hypothesize that combined treatment may provide the best patient outcome.

Association between alcohol dehydrogenase 1C gene *1/*2 polymorphism and pancreatitis risk: a meta-analysis

Numerous studies have focused on the relationship be-tween alcohol dehydrogenase 1C gene (ADH1C) *1/*2 polymorphism (Ile350Val, rs698, also known as ADH1C *1/*2) and pancreatitis risk, but the results have been inconsistent. Thus, we conducted a meta-anal-ysis to more precisely estimate this association. Relevant publications were searched in several widely used databases and 9 eligible studies were included in the meta-analysis. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the strength of the association. Significant associations between ADH1C *1/*2 poly-morphism and pancreatitis risk were observed in both overall meta-analysis for 12 vs 22 (OR = 1.53, 95%CI = 1.12-2.10) and 11 + 12 vs 22 (OR = 1.44, 95%CI = 1.07-1.95), and the chronic alcoholic pancre-atitis subgroup for 12 vs 22 (OR = 1.64, 95%CI = 1.17-2.29) and 11 + 12 vs 22 (OR = 1.53, 95%CI = 1.11-2.11). Significant pancreatitis risk variation was also detected in Caucasians for 11 + 12 vs 22 (OR = 1.45, 95%CI = 1.07-1.98). In conclusion, the ADH1C *1/*2 polymorphism is likely associated with pancreatitis risk, particularly chronic alcoholic pancreatitis risk, with the *1 allele functioning as a risk factor.

Analysis of soluble urokinase plasminogen activator receptor in multiple myeloma for predicting prognosis

Multiple myeloma is a type of malignancy, which affects the plasma cells of the bone marrow. Recent studies have found that malignant plasma cells may express urokinase plasminogen activator (uPA) and uPA receptor (uPAR), and that initiation of proteolytic events by this system contributes to the process of invasion and destruction of the bone marrow. Studies have also suggested that the level of the soluble form of uPAR (suPAR) may act as a marker for prognosis in patients with multiple myeloma, and that there is an association between uPAR/suPAR expression, and clinical characteristics, efficacy of treatment in disease control and patient survival. In order to investigate this, the present study used flow cytometry to detect the monoclonal antibodies associated with multiple myeloma, specifically, uPAR (CD87), CD56 and CD38. Patients with multiple myeloma were divided into the following groups: The effective groups (remission and stable disease) and the ineffective group (progressive disease). suPAR expression in the effective groups was 257.6±32.47 pg/ml and 331.0±99.80 pg/ml respectively, which was not significantly different from that of the normal control group (P>0.05). By contrast, the suPAR level in the invalid group was 562.2±291.0 pg/ml, which was significantly different from the levels in the normal control group (P<0.01) and the effective groups (P<0.05). suPAR levels were positively correlated with disease stage (P<0.01), renal function (P<0.05), C-reactive protein (P<0.005), β2-microglobulin (P<0.001), extramedullary involvement (P<0.001), chromosome 13 deletion (P<0.01) and survival >2 years (P<0.01). They were was negatively correlated with hemoglobin concentration. No correlation was observed between uPAR expression and suPAR levels. The present study also indicated that the stage of disease and suPAR expression were independent factors, which predicted survival of <2 years. In conclusion, high suPAR expression appears to predict disease progression, a shortened survival period and early extramedullary infiltration.

Relationship between vitamin D (1,25-dihydroxyvitamin D3) receptor gene polymorphisms and primary biliary cirrhosis risk: a meta-analysis

The vitamin D (1,25-dihydroxyvitamin D3) receptor (VDR) gene encodes a protein that functions in the transcriptional regulation of vitamin D-responsive genes and plays a role in innate immunity and adaptive immune responses. In this study, we investigated the relationship between VDR polymorphisms (BsmI, ApaI, and TaqI) and primary biliary cirrhosis (PBC) risk. We conducted an overall meta-analysis and subgroup meta-analysis based on ethnicity that included a total of 6 eligible studies (672 cases and 1148 controls). We detected no significant PBC risk variation for all genetic models in the overall analysis and in the subgroup analysis based on ethnicity for the BsmI polymorphism. For the ApaI polymorphism, significant associations were observed in the overall analysis as well as in the Asian subgroup. Furthermore, in the subgroup analysis based on ethnicity, a significant association was observed in the Caucasian subgroup but not in the Asian subgroup for the TaqI polymorphism. Based on the results of our meta-analysis, the VDR BsmI polymorphism may not be associated with PBC risk, while the VDR ApaI polymorphism is likely associated with PBC risk, particularly in Asians. The VDR TaqI polymorphism may be associated with PBC risk in Caucasians.

[Role of CD47 in hematologic malignancies]

CD47 is a ubiquitously expressed transmembrane glycoprotein on surface of many cells. Through its interaction with integrin, signal regulatory protein alpha (SIRPα) and thrombin sensitive protein-1 (TSP-1), it plays important roles in various immunological processes including inflammatory response, immune response and tumor immunity. Recently, it has been found that CD47 interacts with SIRPα expressed on phagocytic cells, which transfers a negative signal when being activated. By the mechanisms described above, CD47-SIRPα signal complex is involved in the pathogenesis of hematological diseases and might provide some informations for the therapy of patients. This review focuses on the structure and immunoregulatory functions of CD47, the mechanism of CD47 in tumor therapy, the CD47 and hematologic malignancies including acute leukemia, B-cell lymphoma and multiple myeloma, as well as CD47 and hematopoietic stem cell transplantation.

Aberrant methylation of suppressor of cytokine signalling-1 (SOCS-1) gene in pancreatic ductal neoplasms

The suppressor of cytokine signalling-1 (SOCS-1) gene is frequently silenced in human hepatocellular carcinoma by aberrant methylation. The aim of this study was to determine if SOCS-1 is inactivated in pancreatic ductal neoplasms, and to investigate if aberrant methylation of this gene affected the Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway. Aberrant methylation in the CpG island of the SOCS-1 gene was detected in six of 19 (31.6%) human pancreatic cancer cell lines using methylation-specific PCR, and was associated with a loss or reduction of gene expression in five of the six methylated cell lines. Thirteen of 60 pancreatic ductal adenocarcinomas (21.7%) and two of 34 intraductal papillary mucinous neoplasms (IPMNs) (5.9%) had methylated SOCS-1. In contrast, SOCS-1 methylation was not seen in pancreatic normal ductal epithelia (zero out of 15), in pancreatic intraepithelial neoplasia (PanINs) (zero out of 49) or in the IPMNs without infiltrating cancer (zero out of 20). 5-Aza-2'-deoxycytidine treatment of the SOCS-1-methylated pancreatic cancer cell lines led to restoration of SOCS-1 gene expression. Interleukin-6, which has been shown to act through the JAK/STAT pathway to increase cell growth, induced modest time and dose-dependent cell proliferation in a SOCS-1-methylated cell line (PL10, P=0.015) but not in two unmethylated cell lines. These results indicate that loss of SOCS-1 gene is associated with transcriptional silencing and may have growth-promoting effects, and that its methylation is a useful marker of pancreatic cancer.

Differing rates of loss of DPC4 expression and of p53 overexpression among carcinomas of the proximal and distal bile ducts

BACKGROUND

Biliary tract carcinomas are clinically heterogeneous. It is not known if molecular heterogeneity underlies the clinical differences.

METHODS

The authors evaluated 128 bile duct carcinomas, 88 of the distal common bile duct and 40 of more proximal origin (28 perihilar carcinomas, 12 intrahepatic carcinomas), immunohistochemically for abnormalities in the expression of the products of the DPC4 and p53 tumor-suppressor genes. Prognostic factors were evaluated in the series of distal bile duct carcinomas for which follow-up information was available.

RESULTS

The authors found that a significantly higher percentage of distal bile duct carcinomas (55%) demonstrated loss of DPC4 expression than did the proximal bile duct carcinomas (15%; P < 0.001). They also found that a significantly higher percentage of the distal tumors abnormally expressed the p53 gene product (51% vs. 26%; P < 0.001). Among the distal common bile duct carcinomas, the presence of poorly differentiated histology correlated with decreased survival in multivariate analysis, while labeling for p53 or Dpc4, margin status, lymph node status, and tumor dimension did not correlate significantly with survival.

CONCLUSIONS

These results demonstrate that abnormalities in DPC4 and p53 gene expression are frequent in distal common bile duct carcinomas, just as they are in pancreatic ductal adenocarcinoma, suggesting that these two tumor types might share a similar molecular pathogenesis. They also show that proximal and distal bile duct carcinomas have different patterns of inactivation of tumor-suppressor genes, indicating that they often arise through different molecular mechanisms likely reflecting their differing etiologies.

High-throughput drug screening of the DPC4 tumor-suppressor pathway in human pancreatic cancer cells

OBJECTIVE

To screen a library of small chemicals for compounds that activate the DPC4 signal transduction pathway in a human pancreatic cancer cell line.

SUMMARY BACKGROUND DATA

Various tumor-suppressor genes are mutated in all human cancers. Specifically, DPC4 (deleted in pancreatic carcinoma, locus 4 or MADH4/SMAD4) is a tumor-suppressor gene mutated in approximately 50% of human pancreatic adenocarcinomas. DPC4 plays an important role in the well-studied transforming growth factor-beta (TGFbeta) signaling pathway. It would be useful to identify therapies that augment or restore the downstream functions of this critical signal transduction pathway, in hopes that such therapy would have a rational role in anticancer therapy.

METHODS

Using a commercially available plasmid vector with a luciferase reporter gene already incorporated, a DPC4-specific reporter construct was genetically engineered. This was done by inserting six copies of the palindromic Smad binding element (6SBE), which is a DNA binding element specific for DPC4, in front of the minimal promoter in the plasmid. This construct was then stably integrated into the genome of a human pancreatic cancer cell line (PANC-1) that has wild-type DPC4. Several stably transfected clones were tested for basal luciferase expression and inducibility with TGFbeta, which is known to activate the DPC4 signal transduction pathway. A single transfected clone was chosen for the drug screen based on basal luciferase (reporter) expression and TGFbeta inducibility. A systematic screen of the chemical library was then performed, using luciferase activity to detect DPC4 activity and induction of the signaling pathway.

RESULTS

A high-throughput system based on this stably integrated reporter system was used to screen a library of 16,320 random compounds to identify agents that conferred robust augmentation of the DPC4 signal transduction pathway. Of the 16,320 compounds screened, 11 were associated with a 2- to 5-fold induction of luciferase activity, and one with a 12-fold activation. The latter compound was shown to be a novel histone deacetylase inhibitor and was further characterized.

CONCLUSIONS

These results confirm the feasibility of a specific high-throughput reporter system to screen a large compound library in human cells efficiently. The screening identified several compounds capable of augmenting DPC4-specific luciferase reporter activity, and a specific mechanism for one compound was identified. The discovery of such agents will aid our understanding of complex tumor-suppressive signaling pathways and may identify other potential therapeutic targets within this critical signaling pathway. In addition, random drug screening provides an unbiased method for identifying drugs or lead compounds for potential therapeutic use.

[Transplantation of peripheral nerves and their tissue constituents to repair axotomized retinal ganglion cells in adult mammals]

We focus on how peripheral nerves or their tissue constituents including Schwann cells, fibroblasts and neurotrophic factors are used to overcome the unfavorable extrinsic CNS environment and upregulate the intrinsic growth potential of injured neurons for the enhancement of neuronal survival and axonal regeneration of axotomized retinal ganglion cells in adult mammals.

ACVR1B (ALK4, activin receptor type 1B) gene mutations in pancreatic carcinoma

DPC4 is known to mediate signals initiated by type beta transforming growth factor (TGFbeta) as well as by other TGFbeta superfamily ligands such as activin and BMP (bone morphogenic proteins), but mutational surveys of such non-TGFbeta receptors have been negative to date. Here we describe the gene structure and novel somatic mutations of the activin type I receptor, ACVR1B, in pancreatic cancer. ACVR1B has not been described previously as a mutated tumor-suppressor gene.

Molecular genetics of ductal pancreatic neoplasia

The molecular genetic profiles that characterize pancreatic ductal neoplasia have taken shape recently with the help of immunohistochemistry and the establishment of the nomenclature describing pancreatic ductal tumorigenesis. K-ras mutations frequently occur early, changes in the expression and genetic integrity of the p16 gene appear in intermediate lesions, and the inactivation of the p53, DPC4, and BRCA2 genes occur late in the neoplastic progression. Tumor-suppressor genes inactivated in pancreatic cancer such as ALK5, TGFBR2, MKK4, and STK11/LKB1 have been identified, although their roles in tumor progression are not yet well defined. Additional discoveries in this tumor system may be on the horizon, will further refine the molecular genetic profiles for the disease, and should suggest some clinical uses for this fund of knowledge.

A novel histone deacetylase inhibitor identified by high-throughput transcriptional screening of a compound library

Libraries of compounds are increasingly becoming commercially available for the use of individual academic laboratories. A high-throughput system based on a stably integrated transcriptional reporter was used to screen a library of random compounds to identify agents that conferred robust augmentation of a signal transduction pathway. A novel histone deacetylase (HDAC) inhibitor, termed scriptaid, conferred the greatest effect, a 12- to 18-fold augmentation. This facilitation of transcriptional events was generally applicable to exogenous gene constructs, including viral and cellular promoters, different cell lines and reporter genes, and stably integrated and transiently introduced sequences. Scriptaid did not interfere with a further induction provided by stimulation of the cognate signal transduction pathway (transforming growth factor beta/Smad4), which implied the functional independence of ligand-stimulated transcriptional activation and histone acetylation states in this system. Additional insights into this and other signal transduction systems are likely to be afforded through the application of compound screening technologies.

Immunohistochemical labeling for dpc4 mirrors genetic status in pancreatic adenocarcinomas : a new marker of DPC4 inactivation

DPC4 (MADH4, SMAD4) is a tumor suppressor gene inactivated by allelic loss in approximately 55% of pancreatic adenocarcinomas. Unfortunately, it can be technically very difficult to detect the inactivation of DPC4 at the genetic level because genetic analyses require the microdissection of relatively pure samples of neoplastic and normal tissues. This is especially true for pancreatic adenocarcinomas, which elicit vigorous, non-neoplastic, stromal responses. Immunohistochemical labeling can overcome this hurdle because it preserves morphological information. We therefore studied the expression of the DPC4 gene product in 46 cancers, including 5 cancer cell lines by Western blot analysis and 41 primary periampullary adenocarcinomas by immunohistochemistry. The status of exons 1-11 of the DPC4 gene in all 46 of the cancers had been previously characterized at the molecular level, allowing us to correlate Dpc4 expression directly with gene status. Three cell lines had wild-type DPC4 genes, and Dpc4 expression was detected in all three by Western blot. The two cell lines with homozygously deleted DPC4 genes did not show Dpc4 protein by Western blot analysis. Immunohistochemical labeling revealed that 17 (94%) of the 18 primary adenocarcinomas with wild-type DPC4 genes expressed the DPC4 gene product, whereas 21 (91%) of 23 primary adenocarcinomas with inactivated DPC4 genes did not. Cases in which there was discordance between the immunohistochemical labeling and the genetic analyses were reanalyzed genetically, and we identified a deletion in exon 0 of DPC4 in one of these cases. This is the first report of a mutation in exon 0 of DPC4 in a pancreatic cancer. The contrast between the strong expression of Dpc4 by normal tissues and the loss of expression in the carcinomas was highlighted in several cases in which an infiltrating cancer was identified growing into a benign duct. These observations suggest that immunohistochemical labeling for the DPC4 gene product is an extremely sensitive and specific marker for DPC4 gene alterations in pancreatic carcinomas. The sensitivity and specificity of immunohistochemical labeling for Dpc4 in other periampullary carcinomas has yet to be determined.

Novel homozygous deletions of chromosomal band 18q22 in pancreatic adenocarcinoma identified by STS marker scanning

The identification of homozygous deletions in sporadic neoplasms has been pivotal in the positional cloning of several tumor suppressor genes. Chromosomal arm 18q harbors the DPC4, SMAD2, and DCC genes and is suspected on the basis of high frequencies of allelic loss to harbor additional tumor suppressor genes. We applied high-resolution sequence-tagged site (STS) marker scanning to a panel of 106 pancreatic adenocarcinomas to identify novel regions of homozygous deletions on 18q. Three homozygous deletions were identified. Physical mapping of these deletions showed them to be nonoverlapping, but clustered in an approximately 7- to 10-Mb region of chromosome band 18q22. Each deletion spanned physical distances of nearly 1.3 to 3 Mb. A number of transcribed genes map within these deletions. The identification of these homozygous deletions might aid in the identification of novel tumor suppressor genes on chromosomal arm 18q. Genes Chromosomes Cancer 25:370-375, 1999.

Germline and somatic mutations of the STK11/LKB1 Peutz-Jeghers gene in pancreatic and biliary cancers

Peutz-Jeghers syndrome (PJS) is an autosomal-dominant disorder characterized by hamartomatous polyps in the gastrointestinal tract and by pigmented macules of the lips, buccal mucosa, and digits. Less appreciated is the fact that PJS also predisposes patients to an increased risk of gastrointestinal cancer, and pancreatic cancer has been reported in many PJS patients. It was recently shown that germline mutations of the STK11/LKB1 gene are responsible for PJS. We investigated the role of STK11/LKB1 in the development of pancreatic and biliary cancer in patients with and without the PJS. In a PJS patient having a germline splice site mutation in the STK11/LKB1 gene, sequencing analysis of an intestinal polyp and pancreatic cancer from this patient revealed loss of the wild-type allele of the STK11/LKB1 gene in the cancer. Inactivation of STK11/LKB1, by homozygous deletions or somatic sequence mutations coupled with loss of heterozygosity, was also demonstrated in 4-6% of 127 sporadic pancreatic and biliary adenocarcinomas. Our results demonstrate that germline and somatic genetic alterations of the STK11/LKB1 gene may play a causal role in carcinogenesis and that the same gene contributes to the development of both sporadic and familial forms of cancer.

PU.1 and Spi-B are required for normal B cell receptor-mediated signal transduction

PU.1 and Spi-B have previously been implicated in the regulation of genes encoding B cell receptor (BCR) signaling components. Spi-B-/- B lymphocytes respond poorly to BCR stimulation; PU.1-/- mice, however, lack B cells, precluding an analysis of BCR responses. We now show that PU.1+/- Spi-B-/- B cells exhibit more extensive defects than Spi-B-/- B cells, indicating that both PU.1 and Spi-B are required for normal BCR signaling. Strikingly, BCR cross-linking results in substantially reduced protein tyrosine phosphorylation in mutant B cells. Further analysis shows that Igalpha is phosphorylated and syk is recruited and becomes phosphorylated but that BLNK and PLCgamma phosphorylation are defective in mutant cells. Our data support the existence of a novel component coupling syk to downstream targets.

Alterations in pancreatic, biliary, and breast carcinomas support MKK4 as a genetically targeted tumor suppressor gene

Mitogen-activated protein kinase (MAPK) kinase 4 (MKK4) is a component of a stress and cytokine-induced signal transduction pathway involving MAPK proteins. The MKK4 protein has been implicated in activation of JNK1 and p38 MAPK on phosphorylation by conserved kinase pathways. A recent report on the deletion and mutation of the MKK4 gene in human pancreatic, lung, breast, testicle, and colorectal cancer cell lines suggests an additional role for MKK4 in tumor suppression. Both the gene function and the infrequency of mutations might be considered atypical for many human tumor suppressor genes, and constitutional DNA was not previously available to determine whether the reported sequence variants had preceded tumor development. Here, we report that homozygous deletions are detected in 2 of 92 pancreatic adenocarcinomas (2%), 1 of 16 biliary adenocarcinomas (6%), and 1 of 22 breast carcinomas (when combined with reported sequence alterations, 3 of 22 or 14%). In addition, in a panel of 45 pancreatic carcinomas prescreened for loss of heterozygosity, one somatic missense mutation of MKK4 is observed and confirmed in the primary tumor (2%). Mapping of the homozygous deletions further indicated MKK4 to lie at the target of deletion. The finding of a somatic missense mutation in the absence of any other nucleotide polymorphisms or silent nucleotide changes continues to favor MKK4 as a mutationally targeted tumor suppressor gene. Coexistent mutations of other tumor suppressor genes in MKK4-deficient tumors suggest that MKK4 may participate in a tumor suppressive signaling pathway distinct from DPC4, p16, p53, and BRCA2.

Defective B cell receptor-mediated responses in mice lacking the Ets protein, Spi-B

Spi-B is a hematopoietic-specific Ets family transcription factor closely related to PU.1. Previous gene targeting experiments have shown that PU.1 is essential for the production of both lymphocytes and monocytes. We have now generated mice with a null mutation at the Spi-B locus. Unlike PU.1 mutant mice, Spi-B-/- mice are viable, fertile and possess mature B and T lymphocytes. However, Spi-B-/- mice exhibit severe abnormalities in B cell function and selective T cell-dependent humoral immune responses. First, although Spi-B-/- splenic B cells respond normally to lipopolysaccharide stimulation in vitro, these B cells proliferate poorly and die in response to B cell receptor (surface IgM) cross-linking. Secondly, Spi-B-/- mice display abnormal T-dependent antigenic responses in vivo and produce low levels of antigen-specific IgG1, IgG2a and IgG2b after immunization. Finally, Spi-B-/- mice show a dramatic defect in germinal center formation and maintenance. In contrast to wild-type animals, germinal centers in Spi-B-/- mice are smaller and short-lived with significantly increased numbers of apoptotic B cells. Taken together, these results demonstrate that Spi-B is essential for antigen-dependent expansion of B cells, T-dependent immune responses and maturation of normal germinal centers in vivo.

The Ets protein Spi-B is expressed exclusively in B cells and T cells during development

Spi-B and PU.1 are hematopoietic-specific transcription factors that constitute a subfamily of the Ets family of DNA-binding proteins. Here we show that contrary to previous reports, PU.1 and Spi-B have very different expression patterns. PU.1 is expressed at high levels in B cells, mast cells, megakaryocytes, macrophages, neutrophils, and immature erythroid cells and at lower levels in mature erythrocytes. PU.1 is completely absent from peripheral T cells and most T cell lines based on sensitive RT-PCR assays. In contrast, Spi-B is expressed exclusively in lymphoid cells and can be detected in early fetal thymus and spleen. In situ hybridizations of adult murine tissues demonstrate Spi-B mRNA in the medulla of the thymus, the white pulp of the spleen, and the germinal centers of lymph nodes. Spi-B expression is very abundant in B cells and both Spi-B mRNA and protein are detected in some T cells. In situ hybridization and Northern blot analysis suggest that Spi-B gene expression increases during B cell maturation and decreases during T cell maturation. Gel-retardation experiments show that Spi-B can bind to all putative PU.1 binding sites, but do not reveal any preferred Spi-B binding site. Finally, both PU.1 and Spi-B function as transcriptional activators of the immunoglobulin light-chain enhancer E lambda 2.4 when coexpressed with Pip (PU.1-interaction partner) in NIH-3T3 cells. Taken together, these data suggest that differences in patterns of expression between Spi-B and PU.1 distinguish the function of each protein during development of the immune system.

Characterization of a murine Ahr null allele: involvement of the Ah receptor in hepatic growth and development

The Ah receptor (AHR) is a ligand-activated transcription factor that mediates a pleiotropic response to environmental contaminants such as benzo[a]pyrene and 2,3,7,8-tetrachlorodibenzo-p-dioxin. In an effort to gain insight into the physiological role of the AHR and to develop models useful in risk assessment, gene targeting was used to inactivate the murine Ahr gene by homologous recombination. Ahr-/- mice are viable and fertile but show a spectrum of hepatic defects that indicate a role for the AHR in normal liver growth and development. The Ahr-/- phenotype is most severe between 0-3 weeks of age and involves slowed early growth and hepatic defects, including reduced liver weight, transient microvesicular fatty metamorphosis, prolonged extramedullary hematopoiesis, and portal hypercellularity with thickening and fibrosis.

PU. 1 is not essential for early myeloid gene expression but is required for terminal myeloid differentiation

We have previously shown using gene targeting that PU.1 is essential for the development of lymphoid and myeloid lineages during fetal liver hematopoiesis. We now show that PU.1 is required for the maturation of yolk sac-derived myeloid progenitors and for the differentiation of ES cells into macrophages. The role of PU.1 in regulating target genes, thought to be critical in the development of monocytes and granulocytes, has been analyzed. Early genes such as GM-CSFR, G-CSFR, and myeloperoxidase are expressed in PU.1-/- embryos and differentiated PU.1-/- ES cells. However, the expression of genes associated with terminal myeloid differentiation (CD11b, CD64, and M-CSFR) is eliminated in differentiated PU.1-/- ES cells. Development of macrophages is restored with the introduction of a PU.1 cDNA regulated by its own promoter. The PU.1-/- ES cells represent an important model for analyzing myeloid cell development.

Expression and functional significance of an additional ligand for CTLA-4

Effective T-cell activation requires antigen/major histocompatibility complex engagement by the T-cell receptor complex in concert with one or more costimulatory molecules. Recent studies have suggested that the B7 molecule, expressed on most antigen presenting cells, functions as a costimulatory molecule through its interaction with CD28 on T cells. Blocking the CD28/B7 interaction with CTLA4Ig inhibits T-cell activation in vitro and induces unresponsiveness. We demonstrate that another molecule(s), termed B7-2, is expressed constitutively on dendritic cells, is differentially regulated on B cells, and costimulates naive T cells responding to alloantigen. B7-2 is up-regulated by lipopolysaccharide in < 6 hr and is maximally expressed on the majority of B cells by 24 hr. In contrast, B7 is detected only on a subset of activated B cells late (48 hr) after stimulation. In addition, Con A directly induces B7-2 but not B7 expression on B cells. Finally, although both anti-B7 monoclonal antibodies and CTLA4Ig blocked T-cell proliferation to antigen-expressing B7 transfectants, only CTLA4Ig had any significant inhibitory effect on T-cell proliferation to antigens expressed on natural antigen presenting cells, such as dendritic cells. Thus, B7 is not the only costimulatory molecule capable of initiating T-cell responses since a second ligand, B7-2, can provide a necessary second signal for T-cell activation.