Biomedical subjects

L M Blatt

Publications and source records attributed to L M Blatt.

At least 19 recordsLinked to original sources

PubMed2000

Inhibition of hepatitis C virus (HCV)-RNA-dependent translation and replication of a chimeric HCV poliovirus using synthetic stabilized ribozymes.

Ribozymes are catalytic RNA molecules that can be designed to cleave specific RNA sequences. To investigate the potential use of synthetic stabilized ribozymes for the treatment of chronic hepatitis C virus (HCV) infection, we designed and synthesized hammerhead ribozymes targeting 15 conserved sites in the 5' untranslated region (UTR) of HCV RNA. This region forms an internal ribosome entry site that allows for efficient translation of the HCV polyprotein. The 15 synthetic ribozymes contained modified nucleotides and linkages that stabilize the molecules against nuclease degradation. All 15 ribozymes were tested for their ability to reduce expression in an HCV 5' UTR/luciferase reporter system and for their ability to inhibit replication of an HCV-poliovirus (HCV-PV) chimera. Treatment with several ribozymes resulted in significant down-regulation of HCV 5' UTR/luciferase reporter expression (range 40% to 80% inhibition, P <.05). Moreover, several ribozymes showed significant inhibition (>90%, P <.001) of chimeric HCV-PV replication. We further show that the inhibitory activity of ribozymes targeting site 195 of HCV RNA exhibits a sequence-specific dose response, requires an active catalytic ribozyme core, and is dependent on the presence of the HCV 5' UTR. Treatment with synthetic stabilized anti-HCV ribozymes has the potential to aid patients who are infected with HCV by reducing the viral burden through specific targeting and cleavage of the viral genome.

Antiviral Agents↗

PubMed1999

Patients co-infected with human immunodeficiency virus and hepatitis C virus demonstrate higher levels of hepatic HCV RNA.

Serum and liver hepatitis C virus (HCV) RNA levels in patients with hepatitis C have previously been quantified using different techniques. In this work, we used an automated, multicycle, polymerase chain reaction (PCR)-based technique to quantify HCV RNA in 1-2 mm of frozen liver tissue, and in serum, from 70 patients with antibodies to HCV (anti-HCV), with and without human immunodeficiency virus (HIV) co-infection. Stored liver tissue and sera collected at the time of liver biopsy were used for measurement of HCV RNA. Forty-eight HCV patients and 22 HIV/HCV co-infected patients were studied. Co-infected patients had significantly higher median serum and liver HCV RNA (6.7 log copies ml-1 serum and 2.90 log copies microg-1 liver nucleic acids) than patients with HCV alone (6.2 log copies ml-1 serum and 2.19 log copies microg-1 liver nucleic acids). There was only a weak correlation between serum and liver HCV RNA (r = 0.43). There was no correlation between liver and serum HCV RNA and host factors such as duration of disease, CD4 counts, alanine aminotransferase levels or histological score. There was no correlation with HCV genotype. Co-infected patients were more likely to harbour HCV genotype 1 (85%) when compared to patients with HCV alone (58%). An identical genotype was found in liver and serum in 89% of those tested; in 11%, a mixed genotype was present in serum. Patients with HCV genotypes 1 and non-1 had similar histological scores. Hence, an automated PCR-based technique is useful for measuring both liver and serum HCV RNA. Serum HCV genotypes closely paralleled those found in liver tissue. HIV co-infection was associated with higher serum, as well as intrahepatic, HCV RNA levels, by mechanisms not directly related to CD4 counts. The lack of correlation between liver HCV RNA and histology suggests that HCV is not directly cytopathic.

Adult↗

PubMed1999

A pilot study of daily subcutaneous interleukin-10 in patients with chronic hepatitis C infection.

The Th1/Th2 cytokine balance is important in persistence of infection and liver injury in chronic hepatitis C. The aim of this study was to administer the anti-inflammatory cytokine, recombinant human interleukin-10 (rHuIL-10), for 28 days in patients with chronic hepatitis C and to assess the safety and measure the effect on alanine aminotransferase (ALT, a marker of hepatic inflammation) levels and serum hepatitis C virus (HCV) RNA values. Three treatment-naive and 13 interferon (IFN) nonresponder patients (total 16 patients) with compensated chronic HCV infection were enrolled in this study. Patients were randomized to receive rHuIL-10 at a dose of 4 or 8 microg/kg/day as a single daily subcutaneous injection for 28 days. ALT values and serum HCV RNA were measured at days 0, 1, 3, 8, 15, 22, and 28 during therapy and at follow-up 2 and 4 weeks after cessation of the 4-week treatment period. ALT values normalized in 9 of 16 patients during therapy and remained normal until the end of treatment in 8 patients. The decreases in ALT values occurred in both the 4 microg and 8 microg dosage groups and were seen in both IFN naive and nonresponder patients. Mean ALT values fell significantly during the study period but usually returned to pretreatment levels by the end of the 4-week follow-up period (p < 0.05). HCV RNA concentrations did not vary significantly during or after therapy. (No patient had either an increase or a decrease in HCV RNA levels of > or =1.5 log during the study.) The drug was well tolerated, with no adverse symptoms noted. Platelet counts fell transiently to 73,000 and 63,000 in 2 patients. No other toxicity was observed, and no patients discontinued therapy. In chronic hepatitis C, short-term therapy with IL-10 was well tolerated and caused transient normalization of ALT values in 50% of patients, which returned to pretreatment levels on cessation of treatment. There were no significant changes observed in serum HCV RNA concentrations during the study. These immunomodulatory effects are similar to those observed with ribavirin monotherapy in chronic hepatitis C. Further study of rHuIL-10 alone or in combination with antiviral agents in chronic hepatitis C is warranted.

Alanine Transaminase↗

PubMed1999

A predictive model for the development of hepatocellular carcinoma, liver failure, or liver transplantation for patients presenting to clinic with chronic hepatitis C.

OBJECTIVE: Chronic infection with hepatitis C may lead to the development of cirrhosis, liver failure, and hepatocellular carcinoma. However, not all patients progress to these endpoints. Ideally, clinicians could improve their capability of stratifying the risk and the time frame within which their patients will progress to these endpoints. The purpose of the present study was to construct statistical models predicting disease progression for individual patients. METHODS: Study endpoints were the development of hepatocellular carcinoma, liver transplantation, or death due to liver disease. The study cohort was 256 patients with hepatitis C acquired from either blood transfusion or use of intravenous drugs. During follow-up, 17 patients developed hepatocellular carcinoma, seven received liver transplantation, and 12 died from liver disease. RESULTS: On multivariate analysis a history of decompensation (relative risk [RR] 4.321, 95% confidence interval [CI] 1.777-10.511) and the serum albumin (RR 0.253, 95% CI 0.136-0.474) were independently associated with the study endpoints. Patients without a history of decompensation and with a serum albumin > or = 4.1 mg/dl had a 3.2% chance of developing the study endpoints within 5 yr. Patients with a history of decompensation and a serum albumin < 4.1 mg/dl had a 40% chance of developing a study endpoint within 5 yr. Baseline genotype and quantitative RNA were not associated with development of the clinical endpoints, with the exception of patients coinfected with two or more genotypes. CONCLUSION: Thus, the serum albumin and a history of decompensation are useful for predicting the development of hepatocellular carcinoma, liver transplantation, and death due to liver disease among patients with hepatitis C.

Adult↗

PubMed1999

Ultracentrifugation and concentration of a large volume of serum for HCV RNA during treatment may predict sustained and relapse response in chronic HCV infection.

The ability to predict accurately a sustained response during therapy in patients with hepatitis C virus (HCV) infection is unavailable. The aim of this study was to differentiate, during therapy, patients who would relapse from those with a sustained response by ultracentrifugation for residual serum HCV RNA. Sixty-one specimens (from 32 patients) collected during interferon therapy were assessed by ultracentrifugation. All were negative using a quantitative polymerase chain reaction (PCR) (detection limit < or = 100 copies/ml). One-milliliter aliquots were ultracentrifuged at 23,000 x g (160 min), and then the nucleic acid pellet was extracted, precipitated, and resuspended. Qualitative PCR was carried out in quadruplicate using two separate 5'UTR primer sets (8 results/specimen). A specimen was positive if > or = 1 gels was positive compared to controls. At weeks 12 and 24, 9/9 (100%) sustained response patients were negative by ultracentrifugation. In the 23 relapse patients at week 12, 7/12 specimens were positive; at week 24, 7/14 were positive. Earlier time points could not differentiate the patients' eventual response to therapy. The predictive value of a positive ultracentrifugation test for relapse at week 12 or 24 was 100%. The predictive value of a negative test for sustained response was 62% and 50% at week 12 and 24, respectively. These preliminary results indicate that patients with an eventual sustained response will have no detectable serum HCV RNA by week 12 or week 24. A positive result is 100% predictive of relapse.

Adult↗

PubMed1998

Re-treatment of chronic hepatitis C with consensus interferon .

A multicenter, open-label, phase 3 study was conducted in 337 patients with chronic hepatitis C virus (HCV) infection who had either not responded to previous interferon therapy or had relapsed after discontinuation of therapy with either consensus interferon (9 microg) or interferon alpha-2b (3 million U) three times a week for 24 weeks. Patients were randomized to receive a higher dose of consensus interferon (15 microg) administered subcutaneously three times a week for 24 or 48 weeks and then were observed for an additional 24 weeks. Patients who had relapsed after prior interferon therapy were more likely to have a sustained alanine aminotransferase response and HCV RNA response (as measured by reverse transcription-polymerase chain reaction with a sensitivity of < 100 copies/mL) than were patients who had not responded to prior interferon therapy. For relapsers, the sustained HCV RNA response rate was 58% (48 weeks) and 28% (24 weeks). The sustained alanine aminotransferase response for relapsers was 52% (48 weeks) and 39% (24 weeks). The sustained HCV RNA response rate among prior nonresponders was 13% (48 weeks) and 5% (24 weeks), and the sustained alanine aminotransferase response rate for nonresponders was 17% (48 weeks) and 12% (24 weeks). The administration of 15 microg of consensus interferon was well tolerated and was not associated with an increase in the incidence of side effects. These data demonstrate that re-treatment with 15 microg of consensus interferon is safe and effective therapy for patients with chronic hepatitis C who have either not responded to previous interferon therapy or relapsed after discontinuation of interferon therapy.

Adult↗

PubMed1998

Long-term retreatment in chronic hepatitis C patients who were non-responders to an initial course of interferon-alpha 2b.

Nineteen patients with chronic hepatitis C who were virological non-responders (seven responder/relapse and 12 no response) to an initial 24-week course of interferon-alpha 2b (IFN-alpha 2b) at a dose of 3 million units (MU) thrice weekly were retreated for an additional 48 weeks at the same dosing schedule and followed-up for another 24 weeks post-therapy. At the end of follow-up (week 72), six (32%) of the 19 patients were hepatitis C virus (HCV) RNA negative and were virological complete responders to retreatment. The viral genotypes in these six patients included two each with 1b and 3a, one with 2b, and another with 2a/2b; five of the six virological responder patients had cirrhosis. Significant predictors for successful retreatment included lower baseline HCV RNA concentrations prior to the first course of therapy, 2 log10 reductions in serum HCV RNA during the initial treatment and classification into the virological 'responder/relapse' category after the first course of IFN (P < 0.01 for all observations). When the above factors were used to construct a predictive model to determine response to retreatment, it was found that the absence of a 2 log10 drop in HCV RNA concentrations during the first course of IFN therapy was the most reliable indicator of non-response to retreatment (likelihood ratio = 10, P = 0.0014). In addition, the presence of HCV RNA at week 12 of retreatment was 100% predictive of virological non-response to the 48-week course of therapy. Our findings indicate that an additional 48-week course of IFN-alpha 2b therapy at 3 MU thrice weekly will achieve a virological complete response in 60% of patients who had a 2 log10 drop in HCV RNA during their first course of treatment, and measurement of week-12 HCV RNA during retreatment to identify non-responders is beneficial to patients as well as being cost-effective. Thus, a second course of IFN remains a viable option in a subgroup of non-responder patients, regardless of genotype or the presence of compensated cirrhosis.

Adult↗

PubMed1998

Discordance between serum alanine aminotransferase (ALT) and virologic response to IFN-alpha2b in chronic hepatitis C patients with high and low pretreatment serum hepatitis C virus RNA titers.

Although serum alanine aminotransferase (ALT) and hepatitis C virus (HCV) RNA concentrations are primary markers used to assess the clinical benefit of interferon (IFN) therapy in patients with chronic HCV infection, discrepancies between these two variables exist. In this study, 103 patients with chronic hepatitis C were treated with 3 MIU IFN-alpha2b three times weekly for 24 weeks, followed by 24 weeks of observation. ALT and virologic responses were compared in patients with high pretreatment HCV RNA titers (defined as pretreatment HCV RNA concentrations at or above the 75th percentile of the distribution or >5,000,000 copies/ml) and low pretreatment HCV RNA titers (defined as pretreatment concentrations below the 75th percentile or < or =5,000,000 copies/ml). Analysis of the virologic response for the high-titer and low-titer groups demonstrated a significantly greater HCV RNA sustained response in the low-titer group (21%) compared with the high-titer group (7%) (p < 0.05). In contrast, the ALT sustained response was not significantly different between the low-titer group (21%) and the high-titer group (18%). Analysis of the correspondence between biochemical and virologic responses showed that only 38% of patients with high pretreatment HCV RNA titers had both a sustained ALT response and a sustained loss of HCV RNA compared with 75% of patients with low pretreatment HCV RNA titers. The level of agreement between the ALT and HCV RNA responses was greater for the low-titer group compared with the high-titer group (kappa = .6848 and kappa = .4966, respectively). Our results indicate that chronic HCV patients with high pretreatment HCV RNA titers showed greater discordance between sustained ALT and HCV RNA responses compared with patients with low pretreatment HCV RNA titers and that measurement of HCV RNA should be included in the assessment of response to IFN therapy in chronic hepatitis C patients.

Adult↗

PubMed1998

Treatment of chronic hepatitis C virus infection with recombinant consensus interferon.

To assess the safety and efficacy of consensus interferon (IFN-Con-1), 55 patients with chronic hepatitis C infection were treated with either 3, 6, 9, 12, or 15 microg IFN-Con-1 s.c. three times a week for 24 weeks, followed by 24 weeks of observation. There was a dose-response relationship with respect to the number of patients with normalized ALT concentrations or undetectable HCV RNA. At the end of the 24-week treatment period, the serum ALT had normalized in 18% of patients given the 3 microg dose and 42% of patients given the 12 microg or 15 microg doses of IFN-Con-1. At the end of the posttreatment observation period, the serum ALT was still normal in 10% of patients given the 3 microg, 6 microg, or 9 microg doses and in 50% of patients given the 15 microg dose. Also, at the end of the 24-week treatment period, 27% of patients given the 3 microg dose and 75% given the 15 microg dose had undetectable serum HCV RNA. At the end of the posttreatment observation period, the proportion of patients with undetectable HCV RNA ranged from 9% of those given the 3 microg dose to 50% of those given the 15 microg dose. Our study indicates that treatment with IFN-Con-1 appears to be safe and effective. In addition, use of 15 microg of IFN-Con-1 resulted in significantly more patients with sustained ALT normalization and absence of HCV RNA 6 months after cessation of therapy compared with treatment with lower doses of IFN-Con-1. Additional trials are underway to confirm these findings.

Adolescent↗

PubMed1998

The changes in quantitative HCV RNA titers during interferon alpha 2B therapy in patients with chronic hepatitis C infection.

OBJECTIVE: Our aim was to analyze the outcomes and the patterns of response to interferon treatment in patients with chronic hepatitis C using serum HCV RNA as the primary endpoint of therapy. METHODS: Seventy anti-HCV-positive patients were treated with 3 million U of interferon-alpha-2b thrice weekly for 24 wk and followed for an additional 24 wk after cessation of therapy (wk 48). Serum HCV RNA was measured by a reverse transcriptase-polymerase chain reaction method that has a sensitivity of < 100 viral copies per ml. RESULTS: The mean pretreatment HCV RNA was 2.8 +/- 2.2 x 10(6) viral copies per ml. Genotype 1 patients had significantly higher mean baseline viral titers than those with genotype 2 (p = 0.03). At wk 48, 12 (17%) patients were HCV RNA negative and considered virological complete responders (CR) to treatment. The remaining patients were HCV RNA positive at wk 48 and were considered nonresponders to therapy. There were two types of virological nonresponder patients, responder relapse (RR) and no response (NR). The mean baseline HCV RNA level was significantly lower in the virological CR patients (p = 0.0004). At wk 12 and 24 of interferon treatment, both the virological CR and RR patients had lower serum HCV RNA concentrations than the patients in the NR category (p = 0.0001), while at wk 48, only. the virological CR patients had undetectable HCV RNA when compared to the RR and NR patients (p = 0.04). Transient decreases in the HCV RNA titers of > or = 1 log in magnitude were observed in 49% of the NR patients, which rose to pretreatment levels either during or after interferon therapy. CONCLUSIONS: Our findings indicate that measurement of serum HCV RNA precisely defined the responses to interferon therapy. Because the goal is to eliminate virus in patients with chronic hepatitis C infection, then HCV RNA should be used as the primary endpoint of treatment.

Adolescent↗

PubMed1997

Treatment of chronic hepatitis C with consensus interferon: a multicenter, randomized, controlled trial. Consensus Interferon Study Group.

This multicenter, randomized, controlled, double-blind, phase III study in 704 patients with chronic hepatitis C infection compared treatment with consensus interferon (CIFN), a non-natural recombinant type-1 interferon, with a standard regimen of recombinant interferon alfa-2b (IFN-alpha2b). Patients were randomized to receive CIFN at doses of 3 microg or 9 microg, or 15 microg IFN-alpha2b (3 million units), subcutaneously three times weekly for 24 weeks, followed by 24 weeks of observation. Efficacy was assessed by normalization of serum alanine transaminase (ALT) concentration and decrease in serum hepatitis C virus (HCV) RNA concentration below the limit of detection by reverse-transcription polymerase chain reaction (RT-PCR) (100 copies/mL). The beneficial effect of CIFN was greater with the 9-microg dose than the 3-microg dose. The sustained ALT and HCV RNA response rates were 20.3% and 12.1%, respectively, in the 9-microg CIFN cohort and 19.6% and 11.3%, respectively, in the 15-microg IFN-alpha2b cohort. However, patients receiving 9 microg of CIFN had a greater reduction in serum HCV RNA concentrations compared with patients receiving 15 microg IFN-alpha2b over the course of treatment (P < .01). Similarly, analysis of patients infected with HCV genotype 1 showed a greater reduction in serum HCV RNA concentration over the course of treatment for the 9-microg CIFN group when compared with the 15-microg IFN-alpha2b group (P < .01). In addition, a greater percentage of patients infected with HCV genotype 1 treated with 9 microg CIFN had undetectable HCV RNA concentrations when compared with patients in the 15-microg IFN-alpha2b cohort at the end of treatment (24% vs. 15%; P = .04). Improvements in liver histology were noted in all three treatment groups; 52% to 55% of the patients in the three cohorts had at least a 2-unit improvement in the Knodell score at the end of the posttreatment period. The adverse-events profiles were characteristic of treatment with type-1 interferon, and the incidences of anti-interferon antibody formation did not significantly differ among the three treatment groups. These results show that administration of 9 microg CIFN three times weekly for 6 months is safe and is effective in reducing serum HCV RNA concentration.

Adult↗

PubMed1997

Prediction of response during interferon alfa 2b therapy in chronic hepatitis C patients using viral and biochemical characteristics: a comparison.

Patients with chronic hepatitis C (n = 103) were treated for 24 weeks with interferon alfa 2b and followed up for 24 weeks after cessation of therapy (week 48). When hepatitis C virus (HCV) RNA at week 48 was used to assess interferon response, 15 (14.6%) were virological complete responders, and all have remained HCV RNA negative for a mean of 3 years. At week 48, 3 of 15 virological complete responders had elevated alanine transaminase (ALT) values. When serum ALT level was used at week 48 to determine response to interferon, 20 (19.4%) were biochemical complete responders. However, 8 of the 20 patients with normal ALT levels were HCV RNA positive at week 48, and 7 of these individuals have had a recurrence of elevated ALT levels within 3 years after cessation of treatment. These findings indicate that measurement of HCV RNA was more accurate than ALT in determining true responses to interferon therapy. Identification of nonresponders early during the course of interferon treatment showed that an elevated ALT level at week 12 was 92% predictive (odds ratio 3.7) but misidentified 33% (5 of 15) of the patients who were virological complete responders at week 48. In contrast, a positive HCV RNA at week 12 of treatment was 98% predictive (odds ratio 35.5) and misidentified only 6.7% (1 of 15) of the virological complete responders. Thus, positive HCV RNA at week 12 of therapy was more accurate in identifying eventual virological nonresponders than measurement of ALT at this time. Termination of interferon therapy in patients who were HCV RNA positive at week 12 would result in a 27% reduction in the direct medical costs and keep patients from undergoing unnecessary treatment. Therefore, testing for HCV RNA at week 12 to identify nonresponders and then discontinuing their treatment is practical, cost-efficient and beneficial both to patients and to third-party payers.

Adolescent↗

PubMed1996

Cell surface binding characteristics correlate with consensus type I interferon enhanced activity.

The binding characteristics of a genetically engineered consensus interferon with unusually high biologic activity were compared to the characteristics of recombinant interferon-alpha 2. Both interferon-alpha 2 and the consensus interferon produced typical biphasic Scatchard plots, indicating multiple independent binding sites. The consensus interferon, which exhibited a biologic potency more than 10-fold greater than all other type I interferons, also exhibited binding site affinities greater than those for IFN-alpha 2b. In addition, a larger number of high, and low-affinity cell surface sites were recognized by the consensus interferon, resulting in equivalent numbers of sites at reduced molar concentrations compared to IFN-a2b. Thus, at any given biologic activity, similar numbers of sites were bound by the consensus interferon and IFN-alpha 2, despite differences in their molar concentrations. No differences in internalization kinetics were identified between the two interferons, indicating that the differences in cell surface binding may be sufficient to produce the differences in biologic activity.

Cell Line↗

PubMed1996

The biologic activity and molecular characterization of a novel synthetic interferon-alpha species, consensus interferon.

Consensus interferon (Infergen) is a wholly synthetic type I interferon (IFN), developed by scanning several interferon-alpha nonallelic subtypes and assigning the most frequently observed amino acid in each position, resulting in a consensus sequence. The antiviral, antiproliferative, NK cell activation activity, cytokine induction, and interferon-stimulated gene-induction activity of consensus interferon has been compared with naturally occurring type I interferons. In all of these comparisons, consensus interferon had a higher activity when compared, on a mass basis, with IFN-alpha 2a and IFN-alpha 2b, although the activity was the same for all of these parameters on an antiviral unit basis. That a synthetic type I interferon could have higher activities than naturally occurring molecules is surprising and may be a result of the higher affinity for the array of type I interferon receptors demonstrated for consensus interferon when compared with IFN-alpha. In contrast, consensus interferon was shown to be an inferior inducer of IL-1 beta when compared with IFN-alpha. These results may reflect differential binding to multiple accessory proteins interacting with a type I interferon receptor. These unique biologic properties may lead to a favorable clinical benefit for consensus interferon when compared with the naturally occurring recombinant molecules. Ongoing clinical trials will ascertain whether consensus interferon can be used in a wide array of disease situations, such as chronic viral infections and certain malignancies.

Amino Acid Sequence↗

PubMed1996

Human renal cancers resistant to IFN's antiproliferative action exhibit sensitivity to IFN's gene-inducing and antiviral actions.

PURPOSE: Although treatment with interferon-alpha (IFN alpha) results in tumor regression in a subset (< 20%) of patients with renal cell carcinoma, the underlying mechanisms for the resistance of renal cancer (RC) cells to IFN alpha is unknown. MATERIALS AND METHODS: We examined 5 RC lines resistant and 5 RC lines sensitive to the antiproliferative effects of IFN alpha for differences in: 1) the number of IFN binding sites, 2) the number of signal-transducing IFNAR-1 chains of the IFN alpha receptor, 3) IFN alpha receptor structure, 4) IFN-stimulated gene (ISG) expression and 5) IFN alpha sensitivity in antiviral assays. RESULTS: No structural alterations in the IFN alpha receptor were detected in any RC line examined, although varying numbers of ligand binding sites and IFNAR-1 signal transducer chains were present. All 5 IFN-sensitive, and 4 of 5 IFN-resistant RC lines were sensitive to the antiviral and gene-inducing actions of IFN alpha. CONCLUSIONS: The resistance of RC lines to IFN's antiproliferative action is not due to defects in ligand binding or in IFN-receptor structure. Our results indicate that the defective antiproliferative response in most RC cells is not due to their failure to induce the gene-inducing and antiviral effects of IFN alpha.

Antineoplastic Agents↗

PubMed1996

Consensus-interferon and platelet-derived growth factor adversely regulate proliferation and migration of Kaposi's sarcoma cells by control of c-myc expression.

Platelet-derived growth factor-B (PDGF-B) is a potent paracrine-acting mitogen in Kaposi's sarcoma (KS) lesions. Interferon-alpha is widely used for clinical treatment of KS. Here we show that platelet-derived growth factor-B activates proliferation and migration of cultivated AIDS-KS spindle cells whereas interferon-alpha acts as an inhibitor. At the molecular level, these opposite activities of platelet-derived growth factor-B and interferon-alpha converged onto the adverse regulation of the c-myc gene expression. Platelet-derived growth factor-B induced c-myc mRNA and protein synthesis in cultivated AIDS-KS spindle cells whereas interferon-alpha inhibited these processes. Using c-myc-specific phoshothioate antisense oligodeoxynucleotides, we demonstrated that down-regulation of c-myc expression is sufficient to inhibit proliferation and migration of KS spindle cells in vitro. This indicated that c-Myc protein may be an important regulatory molecule of KS spindle cell proliferation and migration. High amounts of the c-Myc protein were detected in the nuclei of KS spindle cells in histological sections of AIDS-KS biopsies. This suggested that the c-myc gene may also regulate proliferation and migration of AIDS-KS spindle cells in vivo. In this case, c-myc may play an important role in the focus of major pathogenic and therapeutic pathways of KS.

Cell Division↗

PubMed1995

Comparison of the in vitro host range of recombinant met-interferon-con1, interferon-alpha 2b, and interferon-beta [corrected].

The antiviral activity of human r-metIFN-con1 was compared with that of IFN-alpha 2b and IFN-beta on a number of human, other primate, rodent, feline, and canine cell lines. Although the specific activities of r-metIFN-con1 and IFN-alpha 2b differed 10-fold, the host range was very similar. The host range of IFN-beta differed from that of r-metIFN-con1 and IFN-alpha 2b in that Vero cells were 100-fold better protected by IFN-beta and MDBK protected at a 100-fold less efficiency. In general, there were only minor differences between the host ranges of the three interferons, human and primate cells being better protected than those of other species. However, the tissue of origin of the cell appears to be more important than the species of origin in defining host range [corrected].

Animals↗

PubMed1995

Type 1 interferon as an antiinflammatory agent: inhibition of lipopolysaccharide-induced interleukin-1 beta and induction of interleukin-1 receptor antagonist.

The effect of two type 1 interferons (r-metIFN-con1 and IFN-alpha 2b) on the induction of specific cytokines and IL-1Ra in whole blood was examined. IFN-gamma was induced at low levels following treatment of diluted whole blood in some but not all subjects. IL-1Ra was induced by both r-metIFN-con1 and IFN-alpha 2b, but with 10- to 100-fold higher induction per ng IFN with r-metIFN-con1 than with IFN-alpha 2b. There was no detectable induction of TNF-alpha, IL-4, or IL-6 by either IFN. The effect of both IFN preparations was measured on LPS-induced inflammatory cytokines. Both IFN preparations inhibited the production of IL-1 beta when added to the diluted blood samples before LPS addition. However, neither IFN had any effect on IL-1 beta synthesis when added at the same time or after LPS induction. When added to total blood cells in the absence of LPS at low concentration (up to 100 pg/ml), IFN slightly stimulated IL-1 beta production, but at 1000 pg/ml or greater there was significant inhibition of IL-1 beta production. These results suggest that type I IFNs play a role in regulating the inflammatory response.

Anti-Inflammatory Agents↗