Antiproliferative effect of 1α,25-dihydroxyvitamin D3 involves upregulation of cyclin-dependent kinase inhibitor p21 in human pancreatic cancer cells

BACKGROUND/AIMS

The aim of this study was to investigate the effect of 1α,25-dihydroxyvitamin D3 on proliferation of human pancreatic cancer cell lines and to identify related cell cycle regulatory proteins with antiproliferative effects.

METHODOLOGY

Human pancreatic cancer cell lines SUIT-2 and its four sublines, and Panc-1, AsPC-1, and MiaPaCa-2 were treated with1α,25-dihydroxyvitamin D3. The number of cells was measured by the MTT method, and the cell cycle regulatory proteins were then analyzed by Western blotting.

RESULTS

Eight human pancreatic cancer cell lines expressed vitamin D receptor (VDR) mRNA. 1α,25-dihydroxyvitamin D3 inhibited proliferation of SUIT-2 and its sublines. We found p21 to be upregulated after 24 hours in S2-028, the cell line in which proliferation was most inhibited by 1α,25-dihydroxyvitamin D3.

CONCLUSIONS

1α,25-dihydroxyvitamin D3 inhibited proliferation of pancreatic cancer cells and is involved in the upregulation of cyclin-dependent kinase inhibitor p21.

Thrombin stimulates integrin β1-dependent adhesion of human pancreatic cancer cells to vitronectin through protease-activated receptor (PAR)-1

BACKGROUND/AIMS

The aim of this study was to investigate the effect of thrombin and the thrombin receptor protease-activated receptor (PAR)-1 on adhesion of human pancreatic cancer cell lines to extracellular matrices (ECMs) and to identify related integrins with these effects.

METHODOLOGY

Human pancreatic cancer cell lines SUIT-2 and its four sublines, and Panc- 1, AsPC-1 and MiaPaCa-2 were treated with thrombin, PAR-1 agonist TRAP-6, PAR-1 antagonist SCH79797, or anti-integrin ±vβ3, ±vβ5 and β1 monoclonal antibodies. Cells were incubated for 45 minutes on micro titer plates that were pre-coated with ECMs (fibronectin, laminin, vitronectin, type IV collagen). The number of adherent cells was measured by the MTT method.

RESULTS

Eight human pancreatic cancer cell lines expressed PAR-1. Thrombin significantly enhanced adhesion of SUIT-2 and its sublines and MiaPaCa-2 to vitronectin, especially in the SUIT-2 subline S2-007. We obtained similar results on S2-007 cells through treatment with TRAP-6. However, SCH79797 inhibited the effect of thrombin. Furthermore, anti-integrin β1 antibody conspicuously inhibited 1U/mL thrombin-induced enhancement of adhesion to vitronectin.

CONCLUSIONS

Thrombin significantly enhanced adhesion of pancreatic cancer cells to vitronectin through PAR- 1 depending on the presence of integrin β1. Suppression of thrombin action by anti-integrin β1 antibody will become a useful therapy against pancreatic cancer.

Differential expression of organic anion transporters in rats subjected to 70% or 90% hepatectomy

BACKGROUND/AIMS

Differences in hepatic organic anion transporters were compared in rats to identify a causative factor for early stage acute hepatic failure after 70% or 90% hepatectomy (Hx).

METHODOLOGY

Male Wistar rats (8 weeks, 250-330g) were randomly assigned to one of two groups for 70% Hx or 90% Hx, and sacrificed at 0, 6, 12, 24, 48, or 72 hours after Hx. Posthepatectomy expression of the bile salt export pump (Bsep), multidrug resistance proteins 2 and 3 (Mrp2, Mrp3), sodium-dependent taurocholate co-transporting polypeptide (Ntcp), and organic anion transporting polypeptides 1 and 2 (Oatp1, Oatp2) were analyzed by Northern blotting. Serum liver function tests were also performed.

RESULTS

Postoperative survival rates at 72 hours after 70% and 90% Hx were 100% and 50%, respectively. mRNA expression of Bsep and Mrp3 was increased after 90% Hx, while decreased after 70% Hx. These values were significantly greater at 12 and 24 hours after 90% Hx than after 70% Hx (p < 0.05). In contrast, Mrp2 expression was downregulated to a half of the preoperative level after 90% Hx, while increased after 70% Hx. mRNA expression of uptake transporters (Ntcp, Oatp1, Oatp2) was decreased after 70% Hx and 90% Hx with a similar extent. Total serum bilirubin and bile acid levels were significantly increased after both hepatectomy procedures with a greater extent after 90% Hx.

CONCLUSIONS

Alteration of mRNA expression of Bsep, Mrp2 and Mrp3 may be characteristic behavior in the early stage of acute liver failure.

Transarterial infusion chemotherapy with epirubicin in water-in-oil-in-water emulsion for recurrent hepatocellular carcinoma in the residual liver after hepatectomy

PURPOSE

To evaluate the midterm results of transarterial infusion (TAI) with water-in-oil-in-water (W/O/W) emulsion containing an anticancer agent for patients with recurrent hepatocellular carcinoma (HCC) after surgical resection.

MATERIALS AND METHODS

We retrospectively analyzed the results of TAI of W/O/W emulsion containing epirubicin for 18 consecutive patients with recurrent HCC after surgical resection. Fourteen patients were males and four were females; their ages ranged from 51 to 86 years (mean 69.8 years). TAI was repeated every 1-6 months based on the response of the tumor. A total of 41 TAI procedures were performed for 18 patients. Angiographically, recurrent HCC appeared a single nodule in nine patients and was multinodular in other nine patients. TAI was performed selectively in 27 procedures and non-selectively in 14 procedures. Maximum response within 3 months was rated as follows: a complete response (CR, complete disappearance of tumor and no evidence of new lesions); partial response (PR, a reduction of <50% in total volume of all tumors calculated from the two longest perpendicular diameters without a new lesion); no response (NC, a reduction of <50% in total volume or an increase of <25% without a new lesion); or progression of disease (PD, an increase of >25% in total volume or evidence of new lesions). Survival time was defined as the time from the date of first TAI to the date of death or last follow-up (median follow-up time: 17 months) and the survival curve was estimated using the Kaplan-Meier method.

RESULTS

The CR rate was 33% and the effective response rate (CR rate+PR rate) was 78%. Survival from the time of initial TAI was 94% at 1 year, 76% at 2 years, and 76% at 3 years.

CONCLUSIONS

TAI of W/O/W emulsion may be an effective treatment for patients with recurrent HCC after surgical resection.

Analysis of 20-year follow-up study of LVP regimen for adult acute lymphoblastic leukemia

In an attempt to develop a new intensive chemotherapy for adults with untreated acute lymphoblastic leukemia (ALL), 3 sequential programs were designed for 62 patients (age range, 15 to 74 years; median age, 32 years) consisting of the LVP-79 (1979-1984, 27 patients), LVP-85 (1984-1986, 14 patients), and LVP-87 (1987-1989, 21 patients) regimens. The influence of clinical and biologic characteristics on the patient outcome was also examined. L-asparaginase (L-asp), vincristine, and prednisolone, defined collectively as LVP, were administered for induction chemotherapy in all protocols. After achieving complete remission (CR), patients underwent 2 years of multi-agent consolidation, intensification, and maintenance therapy consisting of various combinations. No significant differences were noted between the 3 groups regarding CR rate or survival. In total, 47 of 62 patients (75.8%) achieved CR. The median overall survival (OS) and median CR durations were 550 days and 341 days, respectively. Overall, the estimated survival rate at 20 years was 18.1%. The disease-free survival rate at 20 years was 26.2%. According to univariate analysis, the most favorable pretreatment characteristic for achieving CR was age. A younger age (<40 years of age), platelet count >30 x 10(9)/L, having L1 morphology (French-American-British [FAB]classification subtype), female sex, and the absence of chromosomal abnormalities also helped improve survival rate. According to multivariate analysis, presence of Ph chromosome was found to be a major influencing factor for OS. Although higher doses of L-asp were administered than those used in previous studies, the adverse effect of L-asp was rarely identified. Therefore, it should be considered one of the key drugs for treatment of adult ALL. Further strategies still need to be developed to obtain better survival in adult ALL.

Interaction between beta-adrenergic signaling and protein kinase C increases cytoplasmic Ca2+ in alveolar type II cells

The interaction between beta-adrenergic signaling and the activation of protein kinase C in alveolar type II cell plays an important role in the regulation of surfactant secretion because the combined application of beta-adrenergic agonist with protein kinase C activator to the cells stimulates the secretion synergistically. However, the mechanisms underlying the interaction are not clear. In the present study, we examined the combined effect of terbutaline with phorbol 12-myristate 13-acetate (PMA) on cytoplasmic free Ca2+ concentration ([Ca2+]i) in rat alveolar type II cells. The combined application of terbutaline with PMA to the cells rapidly increased [Ca2+]i, although neither of them affected it by itself. Similar increases of [Ca2+]i were observed in other combinations, such as terbutaline with 1-oleoyl-2-acetyl-sn-glycerol, and forskolin with PMA. Either the removal of extracellular Ca2+ or the addition of Co2+ remarkably suppressed the increase of [Ca2+]i induced by the combination of terbutaline with PMA. In addition, Co2+ inhibited the phosphatidylcholine secretion induced by the combination of terbutaline and PMA. These results suggested that the [Ca2+]i increased as a result of the interaction between formation of cyclic AMP and activation of protein kinase C in alveolar type II cells, and that the increase in [Ca2+]i was mediated by the Ca2+ influx through the plasma membrane. This mechanism to modulate [Ca2+]i may play a role in the regulation of surfactant secretion by alveolar type II cells.

Myeloblastoma formation in acute myeloid leukemia

The cell surface markers on the leukemic cells of 76 patients with adult acute myeloid leukemia (AML) have been analyzed by indirect immunofluorescence, and the presence of CD56+ leukemic cells was detected in ten of these patients. Four of these 10 CD56+ AML patients developed extramedullary myeloblastomas and in two of them an intracranial myeloblastoma. In contrast, in the remaining 66 CD56- AML patients, only one patient developed a myeloblastoma formation of the subcutaneous. It may be that the CD56 antigen which is an isoform of the neural cell adhesion molecule (NCAM), expressed on neurons, satellite cells of skeletal muscle cells, and on stromal cells, binds these tissues by a homophilic mechanism. CD56+ leukemic cells are capable of invading and of surviving in extramedullary tissues, where they proliferate and develop into a myeloblastoma. Because of this possibility, CD56+ AML patients should be carefully monitored for signs of myeloblastoma formation.

[An erythremia with acquired HbH disease and chromosomal abnormality]

A 56-year-old male was admitted to the Nihon University Hospital because of general fatigue and anemia on September 21st, 1985. He had mild hepato-splenomegaly. Hematological findings showed RBC 286 x 10(4)/microliters, Hb 6.0/dl, reticulocyte count 2.5%, platelet count 9.3 x 10(4)/microliters and WBC 2,400/microliters. An erythroblast per 100 leukocytes counted in a blood film was found. Bone marrow was erythroid hyperplasia with megaloblasts. The erythroblasts were PAS positive but not ringed sideroblasts. Other laboratory data including hemolysis were all negative. This case seemed to be diagnosed as refractory anemia (RA) according to the FAB classification. Chromosomal analysis of marrow cells, however, all revealed 46, XY, 20q- at diagnosis and 46, XY, 7q- 20q- after 22 months. Furthermore, Hb electrophoresis ahd family study indicated the presence of acquired HbH disease. Neither erythroid bursts (BFU-e) nor late erythroid progenitors (CFU-e) were detected. He has had progressive anemia without proliferation of blasts for over 2 years. From these findings, we postulate that the entity of erythremia should be distinguished from RA including many heterogeneous diseases.

[DBMP-85 was effective at diagnosis and LVP was effective at relapse in a case of acute mixed leukemia]

A 16 year-old boy was admitted to our hospital in April 1985, because of bilateral submandibular swellings. Hematological examination revealed Hb was 7.3 g/dl, WBC was 89,000/microliters (76% blast), and platelet was 154,000/microliters. His bone marrow was hypercellular and consisted with 91% blasts. Myeloperoxidase staining was positive for 38% of blasts. Auer rods were seen in some of blasts. Thus, the diagnosis was M1 according to FAB classification. Cytogenetic studies of 20 marrow cells were performed and all cells had 46, XY, -1, -7, 3q-, 7q-, 17q+, +2mar. Eighty five percent of blasts expressed HLA-DR and 43% of blasts expressed CD2 and CD13 simultaneously. Thus, this leukemia was considered as the hybrid type of acute mixed leukemia by surface marker analysis. DBMP-85 regimen, the chemotherapy for AML, was started after admission and complete remission (CR) was attained in June 1985. After 4 courses of post remission chemotherapy, he discharged in December 1985 and was followed at our outpatient clinic without chemotherapy. His disease was relapsed in June 1986, and the combination chemotherapy with mitoxantrone, etoposide and Ara-C was applied to him but failed to attain CR. Then, LVP protocol, the chemotherapy for ALL, was started and CR was achieved. The blasts at relapse had morphologically myeloid features, and expressed HLA-DR, CD2 and CD13 as well as at diagnosis. Cytogenetic studies at relapse showed some karyotype except gaining 12p- anomaly. Therefore, same blasts were considered to emerge at relapse. Our case suggests that LVP therapy may be effective for AML expressing myeloid and lymphoid surface markers.