[Expression of succinate dehydrogenase subunit protein in succinate dehydrogenase-deficient gastrointestinal stromal tumors].

Objective: To investigate the expression of succinate dehydrogenase complex subunit protein in succinate dehydrogenase-deficient gastrointestinal stromal tumors (SDH-deficient GISTs). Methods: Three hundred fifty-two cases of GISTs were collected from January 2003 to January 2017 at the Affiliated Hospital of Guizhou Medical University and West China Hospital of Sichuan University.The expression of succinate dehydrogenase subunit protein was detected by immunohistochemical EnVision technique in 352 cases of GISTs, and the negative cases were analyzed for clinicopathologic features and outcome. The gene segments of CKIT exons 9, 11, 13 and 17 and PDGFRA exons 12 and 18 were amplified and detected in SDH-deficient (negative) cases. Results: A total of 15 SDHB-deficient (negative) GISTs (4.3%, 15/352) were found among 352 cases of GISTs. Six patients were male and nine were female. The age of initial diagnosis ranged from 15 to 84 years (median=53 years, mean=47 years). The tumor involved stomach (14 cases) and mesentery (1 case). The tumor sizes varied from 0.5 cm to 15.0 cm (mean=6.9 cm). There were six, six and three cases of epithelioid, mixed and spindle cell types respectively. Eight cases showed multi-nodularity in the wall of stomach. Metastasis to lymph node was noted in four cases, one case showed intraperitoneal implantation metastasis. Metastases to liver, pancreas and lymph node were found in one case, and one case showed vascular invasion. Among SDHB-deficient GISTs, two SDHA-deficient (negative) cases were found (0.6%, 2/352), but there were no SDHC and SDHD deficient (negative) cases. Five of the fifteen SDH-deficient GISTs had follow-up data: one patient died 8 months after surgery from unknown cause, four had no recurrences or metastases, and there was no history of paraganglioma and pulmonary chondroma found in patients and their families. No mutation in CKIT and PDGFRA gene was identified in 15 cases of SDH-deficient GISTs. Conclusion: SDH-deficient GISTs have unique clinicopathologic features and a favorable prognosis, and a small proportion of cases are SDHA-deficient.

Suppression of tumorigenicity of human lung carcinoma cells after transfection with connexin43.

The human lung carcinoma cell line PG is defective in gap junctional intercellular communication (GJIC). Connexin43 (Cx43) mRNA, which is expressed in normal human lung cells, is undetectable in these tumor cells. To explore if up-regulation of Cx43 gene expression will suppress malignancy of PG cells, Cx43 cDNA was co-transfected with pSV2neo cDNA into PG cells. Control cells were transfected with the blank vector plus neo cDNA. Several stable Cx43 transfectant clones, which acquired high levels of Cx43 expression and the capacity of GJIC, were compared with control clones and the parental cell line, both of which lacked Cx43 expression and GJIC. The control clones resembled the parental cells in exhibiting high cell growth rate, weak attachment to the substratum and a high frequency of colony formation in soft agar. In contrast to the control cells, Cx43 transfected clones showed reduced growth rate, enhanced attachment to the substratum and inhibition of colony formation in soft agar. In vivo results from nude mice experiments showed high tumorigenicity with control clones and inhibition of tumorigenicity in Cx43 transfected clones. The consistency between in vitro and in vivo results strongly suggests a tumor suppressing effect of the Cx43 gene in human lung carcinoma cells.

Clinical application of 131I-HIPDM in the patients with chronic obstructive pulmonary disease.

N,N,N'-trimethyl-N'-2 hydroxy-3-methyl-5-iodobenzyl-1,3-propanediamine iodine-131 (HIPDM) as a lung imaging and metabolic tracer in patients with chronic obstructive pulmonary disease (COPD) were used. 0.4 mCi 131I-HIPDM was rapidly injected into the antecubital vein. The imaging of 131I-HIPDM in the lung was different in various groups. 131I-HIPDM of the clearance by the lungs was a biphasic curve (rapid phase and slow phase). It was displayed that rapid phase of the clearance curve of 131I-HIPDM in the lungs in subjects with chronic obstructive pulmonary emphysema, especially those of smokers were very slow. The rapid phase of the 131I-HIPDM of the right lung clearance was significantly correlated with Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1), Functional Residual Capacity (FRC), Residual Volume (RV), Total Lung Capacity (TLC) p < 0.01; Peak Expiratory Flow Rate (PEFR), Vital Capacity (VC), Maximum Ventilatory Volume (MVV), Arterial oxygen tension (PaO2) p < 0.05. Smoking influence on clearance of 131I-HIPDM of the lung including normal smokers with normal lung function. It was considered that the analysis of the lung release of 131I-HIPDM forms a new lung dysfunction index and it was useful that found early lung damage.

[The antitumor effect of adriamycin conjugated with monoclonal antibody against gastric cancer in vitro and in vivo].

Adriamycin (ADM), an anthracycline cytotoxic agent, was conjugated with monoclonal antibody 3H11 against gastric cancer via the dextran bridge method. The conjugate 3H11-DEX-ADM, with molar ratio of 3H11 to ADM being 1:73, retained antibody activity to 86%. In the cytotoxicity assay, 3H11-DEX-ADM was shown to exhibit increased cytotoxicity against the target cell line BGC 823. Its IC50 was 3.75 fold less than that of free ADM. The antitumor effect of the conjugate was evaluated in tumor-bearing nude mice. The results indicate that the specific antibody conjugate 3H11-DEX-ADM can significantly inhibit the tumor growth. At the dosage level used in the present study (5 micrograms/mouse x 6), 3H11-DEX-ADM showed an inhibition rate of 51.5%, whereas only moderate inhibition rates were observed with free ADM and the control conjugate NIgG-DEX-ADM. In addition, experiment was performed to evaluate the combined cytotoxicity of 3H11-DEX-ADM and the conjugate of mitomycin C (3H11-HSA-MMC) at different ratios. It was shown that the combination has no synergistic effect when their IC50 was compared with that of the two conjugates used alone. The same result was observed on combinations of the two corresponding free drugs.

[Experimental study of tumor directed therapy with gastric cancer monoclonal antibody-mitomycin conjugate combined with propranolol or angiotensin II].

The effects of vasoactive agents propranolol hydrochloride and angiotensin (AT-II) on improving the directed therapy of cancer with the use of conjugate of gastric cancer monoclonal antibody (3H11) and mitomycin C (MMC) were studied. The antibody activity of the conjugate (3H11-HSA-MMC) was retained with the molecular ratio of 1:2:60. In tests with tumor-bearing nude mice, the tumor inhibitory rate of the conjugate alone was found to be 50%, while in conjugate treated mice that also received propranolol or AT-II the tumor inhibitory rate were 79% and 60%, respectively. In tumor-bearing nude mice given 131I-3H11 both propranolol and AT-II increased the tumor uptake of 131I-3H11. These results indicate that these vasoactive agents can change the tissue perfusion ratio via the effect on tumor blood vessels and increase the access of the conjugate to tumor, thereby, enhancing the effectiveness of tumor directed therapy with the use of conjugates.

[The antitumor activity of bovine serum albumin-mediated conjugate of hematoporphyrin derivative with antigastric cancer monoclonal antibody].

Hematoporphyrin derivative (HPD) was conjugated with a murine monoclonal antibody (3H11) against human gastric cancer through bovine serum albumin (BSA) as an intermediate. In this paper, the antitumor activity of indirect conjugate 3H11-BSA-HPD was demonstrated and compared with that of direct conjugate 3H11-HPD in vitro and in vivo. The molar ratios of the conjugates 3H11-BSA-HPD and 3H11-HPD were 1:200 and 1:37, respectively. The cytotoxicities of 3H11-BSA-HPD and 3H11-HPD plus exposure to light were shown to be similar, and much greater than those of free HPD at equivalent HPD concentration in vitro. When tumor-bearing nude mice were treated with the different conjugates or HPD plus exposure to light, all the six mice of the control group formed tumor within 13 days after inoculation of BGC 823 cells (2 x 10(5) cells/mouse), whereas five of the six mice treated with 3H11-BSA-HPD or 3H11-HPD were tumor free for the observation period of 34 days.

[The killing action of a Chinese herbal mixture on human tumor cells in vitro and its effect on cell-cycle].

Previous studies had shown that injection of Chinese herbal mixture (ICHM) had antitumor and anti-metastatic actions on various transplantable animal tumors. In the present study, the authors observed the obvious killing actions of ICHM on human gastric cancer cell line BGC-823 and breast cancer cell line MCF-7 in vitro. The IC50 were 0.02 g crude drug/ml and 0.018 g crude drug/ml respectively. The study of the effect of ICHM on the cell-cycle of BGC-823 cell showed that ICHM decreased the number of cells in S phase and increased the number of cells in G1 phase significantly. The results indicated that the BGC-823 cells was blocked on S phase by ICHM. Meanwhile, ICHM reduced 3H-TdR incorporation into DNA, the cpm value was much lower than that of the control.

[Experimental study of anti-tumor effect with conjugates of monoclonal antibodies and hematoporphyrin derivative].

Hematoporphyrin derivative (HPD) is a photosensitizer for use in photodynamic therapy (PDT). In this paper, HPD was conjugated with monoclonal antibodies 3G9 or 3H11 for use against gastric cancer in order to enhance the photosensitive effect and reduce side effect of PDT. The biological activities of the McAb conjugates were demonstrated. The killing effect on BGC-823 cells of 3G9-HPD or 3H11-HPD conjugates plus exposure to light showed 17 fold and 8.6 fold greater cytotoxicity, respectively than free HPD at an equivalent HPD concentration in vitro. When 3G9-HPD and 3H11-HPD were used in combination at 7:3, 5:5 and 3:7 proportion, the cytotoxicity was increased 12.9, 11.8 and 9.4 fold on target cells, respectively. The results indicate that the cytotoxicity was not further enhanced by the combination scheme. When tumor-bearing nude mice were treated with the different conjugates. Significant inhibition of tumor growth was observed and the survival period of animals was markedly prolonged in comparison with PBS, free HPD and NIgG-HPD treated groups.

[The selective cytotoxicity of monoclonal antibody conjugated with mitomycin C on human gastric cancer cells].

The murine monoclonal antibody (MoAb)3H11 against human gastric cancer was purified with affinity column and conjugated with Mitomycin C (MMC). The binding activity of MoAb in the conjugate retained more than 90% of the original MoAb 3H11 when the molar ratios of MMC to 3H11 was 7-8:1. The killing rate of 3H11-MMC conjugate on human gastric cancer cells BGC 823 was increased significantly than that of free MMC in vitro. The selective cytotoxicity was verified with the following results: (1) the cytotoxicity of the conjugate was much higher than that of normal mouse IgG (nMuIgG) conjugated with MMC; (2) when breast cancer cells MCF-7 was used as target cells instead of BGC 823 cells, much lower cytotoxicity of the conjugate was observed; (3) the cytotoxicity of the conjugate on BGC823 cells could be blocked when the target cells was preincubated with MoAb 3H11, but not with MoAb 3G9 which did combine with BGC823 cells at binding sites different from MoAb 3H11. Nude mice were inoculated with BGC823 cells as a model of gastric cancer and treated with conjugate 3H11-MMC, nMuIgG-MMC, MMC or PBS (ip). It was shown that the time of tumor formation and the rate of tumor growth in 3H11-MMC conjugate treated animals were significantly different from that in control groups. The rate of inhibition of tumor weights was 60.4% for the conjugate 3H11-MMC treated group which was significantly higher than for other groups.