Restoration of natural killer activity in hepatocellular carcinoma by treatment with antibody against granulin-epithelin precursor

Impairment of natural killer (NK) cell activity is an important mechanism of tumor immunoevasion. We have previously shown that expression of granulin-epithelin precursor (GEP) in hepatocellular carcinoma (HCC) cells rendered the cells resistant to NK cell immunosurveillance. Here, we examined whether targeting GEP could rescue NK activity in HCC patients. The current study demonstrated that quantities and activities of NK cells were significantly lower in HCC patients compared with healthy individuals, and were negatively correlated with GEP levels in HCC cells. NK cells demonstrated enhanced expression of the stimulatory receptors natural-killer group 2, member D (NKG2D) and CD69, increased secretion of IFN-γ and perforin, and cytotoxicity against HCC cells upon GEP suppression. Opposite phenotypes of NK cells were observed when GEP was overexpressed in HCC cells. Importantly, GEP blockage by monoclonal antibody A23 restored NK activity in HCC patients and sensitized HCC cells to NK cytotoxicity. Furthermore, A23 induced NK-mediated antibody-dependent cell-mediated cytotoxicity against HCC. In summary, the activity of NK cells in HCC was impaired by GEP expression, which could be rescued by GEP antibody. This study provides new insight for treatments targeting GEP to boost NK activity in HCC patients.

5-Lipoxygenase and epigenetic DNA methylation in aging cultures of cerebellar granule cells

5-Lipoxygenase (5-Lox), an enzyme involved in the metabolism of arachidonic acid participates in the modulation of the proliferation and differentiation of neural stem cells and cerebellar granule cell (CGC) precursors. Since epigenetic mechanisms including DNA methylation regulate 5-LOX expression and have been suggested as possible modulators of stem cell differentiation and aging, using primary cultures of mouse CGC (1, 5, 10, 14, 30 days in vitro; DIV), we studied DNA methylation patterns of the 5-LOX promoter and 5-LOX mRNA levels. We also measured the mRNA and protein content of the DNA methyltransferases DNMT1 and DNMT3a. 5-LOX, DNMT1, and DNMT3a mRNA levels were measured by real-time PCR. We observed that 5-LOX expression and the expression of maintenance DNMT1 is maximal at 1 DIV (proliferating neuronal precursors), whereas the expression of the de novo DNA methyltransferase DNMT3a mRNA increased in aging cultures. We analyzed the methylation status of the 5-LOX promoter using the methylation-sensitive restriction endonucleases AciI, BstUI, HpaII, and HinP1I, which digest unmethylated CpGs while leaving methylated CpGs intact. The 5-LOX DNA methylation increased with the age of the cells. Taken together, our data show that as cultured CGC mature and age in vitro, a decrease in 5-LOX mRNA content is accompanied by an increase in the methylation of the gene DNA. In addition, an increase in DNMT3a but not DNMT1 expression accompanies an increase of 5-LOX methylation during in vitro maturation.

Identification of a surrogate TSL-1 antigen of Trichinella spiralis from a phage library of random peptides

We sought to find a peptide analogue of an important antigen (TSL-1) of Trichinella spiralis which is recognized by the 7C2C5 antibody. A phage library which displays a short (15-mer) randomly-generated peptide at the filament of the minor coat protein of the virion was used for selection by the 7C2C5 antibody. A peptide thus identified, ICDASGLGCWCWSLSP, was found to be a true surrogate since its binding to the antibody could be blocked by the native antigen and, conversely, an antiserum made to the peptide could recognize the native antigen. In addition, the peptide appeared to detect T. spiralis-infected pigs although it was less discriminatory than the native antigen.

Common occurrence of an antiidiotypic antibody that recognizes T14+ anti-DNA antibodies in patients with systemic lupus erythematosus

OBJECTIVE

To investigate whether antibodies to a T14 anti-DNA antibody can be found in patients with systemic lupus erythematosus (SLE).

METHODS

Seventy-six serum samples (37 from patients with SLE) were randomly selected from among sera submitted for routine antinuclear antibody testing. Short, overlapping peptides based on the partial VH (variable region of the heavy chain) sequence of the T14 antibody were synthesized on multipins and screened for reactivity with SLE sera. In addition, selected peptides from T14 and related proteins were synthesized in bulk and screened for reactivity with both SLE and control sera. A monoclonal antibody was generated to determine the prevalence of the T14 idiotype (T14+ Id) in the different study populations.

RESULTS

Antibodies were detected by a peptide based on the third complementarity-determining region (CDR3) of the T14 protein in 15 (41%) of 37 patients with SLE or 15 (54%) of 28 who had anti-DNA antibodies, in 3 (9%) of 34 patients without anti-DNA antibodies (9 of whom had SLE), and in 6 (10%) of 57 healthy controls. In SLE sera, the antiidiotypic (anti-Id) responses (IgM and IgG) correlated well with the anti-DNA responses (IgG), and both responses correlated well with the T14+ Id activity in SLE sera. Control peptides based on the 18/2 (16/6+ Id) and S107 proteins detected low antibody activities in SLE sera, attributable to cross-reactivity with the T14 peptide. A peptide based on an unrelated human antibody was not reactive with these sera.

CONCLUSION

Anti-Id antibodies directed to T14 VHCDR3 were found commonly in the sera of patients with SLE, and they appeared to be induced by the anti-DNA antibodies present in the sera. Based on these findings, these secondary antibodies may be pathogenic in SLE.

Aggressive chemosurgical debulking in patients with advanced ovarian cancer

From July 1986 to June 1989, 43 evaluable patients with advanced ovarian cancer were treated on protocol with initial cytoreductive surgery, two courses of high-intensity intravenous Cytoxan (1000 mg/m2) and cisplatin (120-200 mg/m2) chemotherapy, and repeat debulking laparotomy in an effort to maximize response to a subsequent four cycles of intraperitoneal platinum-based chemotherapy. Two patients were stage IIIA, 2 stage IIIB, 28 stage IIIC, and 11 stage IV. Five tumors were grade 1, 9 grade 2, and 29 grade 3. Thirty-eight (88%) patients had bulky tumor (5-25 cm) found at first laparotomy; 25 of these had greater than 1-cm residual after initial debulking. Following two cycles of intensive intravenous chemotherapy 18 of these 25 had greater than 1-cm disease found at second laparotomy; 12 of 18 underwent secondary cytoreduction to less than 1 cm. Thus, 30 of these 38 (79%) patients entered the intraperitoneal phase of the protocol with less than 1-cm disease. Four patients had 2- to 5-cm tumor at initial laparotomy; two of four were debulked to less than 1-cm residual. All four were found to have less than 1-cm disease at second laparotomy. This combination regimen was well tolerated. There was one treatment-related death. In sum, 42 of 43 patients had tumor greater than 2 cm at staging laparotomy and 38 (88%) had large, bulky disease (5-25 cm); 34 of 43 (79%) entered the intraperitoneal phase of the protocol with optimal (less than 1-cm) disease. Aggressive chemosurgical cytoreduction in patients with bulky advanced ovarian cancer can leave a large proportion of patients with minimal residual disease and maximize their chances of responding to subsequent intraperitoneal chemotherapy.

CA-125 values predictive of clinical response during second-line chemotherapy for epithelial ovarian cancer

Between November 1984 and January 1987, 19 patients with epithelial ovarian cancer were monitored with CA-125 values during second-line therapy. There was a statistically significant association between clinical response to therapy and CA-125 trend when trend was defined as a greater than or equal to 26% change in CA-125 from baseline value to last value prior to demonstration of clinical response (p = 0.0002). In 8 of 11 patients (73%), increasing CA-125 values were predictive of clinical progression during second-line therapy. In six of seven patients (86%), decreasing values predicted clinical regression. Three patients began second-line therapy with baseline values less than 35 U/ml. Two of these progressed during second-line therapy while the third progressed in follow-up. Two of four complete clinical responders completed second-line therapy with values less than 35 U/ml. Both progressed in follow-up with increasing CA-125 values. In this analysis, a 26% change in CA-125 values was a useful predictor of clinical response in patients receiving second-line therapy for epithelial ovarian cancer. Patients undergoing second-line chemotherapy with values less than 35 U/ml may still benefit from CA-125 monitoring.

Tenckhoff catheter cytology in patients with ovarian cancer

In order to expose malignant cells to high concentrations of cytotoxic chemotherapeutic agents, drugs can be instilled directly into the peritoneal cavity of patients with ovarian carcinomas through a Tenckhoff catheter. The peritoneal dialysate removed during such therapy can be examined cytologically for the presence of carcinoma cells. The cytologic specimens from Tenckhoff catheters from 40 consecutive patients with primary ovarian (39) and tubal (1) cancer who received intraperitoneal chemotherapy have been reviewed retrospectively. A total of 237 specimens yielded 78 (33%) positive, 138 (58%) negative, and 21 (9%) inconclusive or suspicious fluids. The major diagnostic problem was the marked mesothelial atypia, which may be related to the high concentrations of cytotoxic agents intimately in contact with the peritoneum. Of the 15 patients who had tissue examined after placement of the catheter (mean interval, 5 months), results agreed with those of the catheter cytologic specimens in ten patients. The catheter cytologic specimen was never positive when histology was negative. Of the 36 patients with evaluable follow-up (mean, 19 months), agreement between the clinical course and the catheter cytologic results was found in 27 patients (75%). Again, interpretation of the catheter specimens was never positive in the face of a benign clinical course. Thus, evaluation of catheter specimens by cytologic examination has a diagnostic sensitivity and specificity of 59% and 100%, respectively. Tenckhoff catheter cytology has proven to be a rather valuable tool to monitor persistent or recurrent intraperitoneal ovarian carcinoma.