Chen-Chiu Tseng

In vitro immunomodulating effect of protein-bound polysaccharide, PSK on peripheral blood, regional nodes, and spleen lymphocytes in patients with gastric cancer.

SummaryPSK, a protein-bound polysaccharide, has been widely used for cancer immunotherapy in Japan. However, the mechanism of its immunomodulatory effect has not been fully clarified. In the present study the in vitro effect of PSK on the lymphocytes of patients with gastric cancer was studied. Culturing lymphocytes with PSK at 5–100 µg/ml increased the level of DNA synthesis, and augmented the cytotoxicities against K562 and KATO-3. Flow-cytometric analysis also showed an increase in the proportion of interleukin-2 (IL-2)-receptor-positive cells after the lymphocytes were cultured with PSK. However the cytotoxicity of cells cultured with PSK was not augmented by the addition of recombinant interferon γ (rIFNγ) and rIL-2. Further experiments using fractionated PSK showed that its biological action is present mainly in fractions having molecular masses >105Da. However, these immunomodulations were not seen in all patients. These results suggest that the susceptibility of lymphocytes to PSK may be different in each patients, and that the immunomodulation by PSK may be mediated by mechanisms independent of IFN and IL-2.

Immunomodulation by orally administered protein-bound polysaccharide PSK in patients with gastrointestinal cancer

The present study was designed to assess the effects of the protein-bound polysaccharide PSK on the immunological status of patients with gastrointestinal cancer. Twenty-nine gastric and 18 colorectal cancer patients were randomly assigned to either the control or PSK group. Patients in the PSK group were given 3.0 g of PSK orally before surgery, either daily or every other day. Patients in the control group received no PSK. The data of peripheral blood lymphocytes (PBL) were compared before and after administration of PSK, and those of the regional node lymphocytes (RNL) were compared between the control and the PSK group. The results indicate that the effects of PSK were significantly influenced by the duration of administration, but not by the frequency of administration. In the patients belonging to the short term PSK group (administration <14 days), the response of the PBL to PSK and Con A become significantly stronger compared to before the administration of PSK, whereas the cytotoxicity against K562 and KATO-3, and the proportion of CD16+ cells increased significantly in those patients belonging to the long term PSK group (≧14 days). In addition, the proportion of CD9 + 11b + suppressor T cells decreased in the RNL of the short term PSK group, whereas the proportion of CD4 + Leu8 - helper T cells in the RNL increased in the long term PSK group.These results suggest that the oral administration of PSK leads to the suppression of suppressor cells in the RNL. Thus, increased numbers of cytotoxic effector cells appear to be activated in the PBL while helper T cells predominate in the RNL.

Chemosensitivity correlation between the primary tumors and simultaneous metastatic lymph nodes of patients evaluated by DNA synthesis inhibition assay

The chemosensitivities of primary tumors (PT) and simultaneous metastatic lymph nodes (MN) to mitomycin C (MMC), 5‐fluorouracil (5‐FU), Adriamycin (ADR) (doxorubicin; Adria Laboratories, Columbus, OH), carboquone (CQ), or cisplatin (CDDP) were assessed in a group of 29 patients (11 gastric, 8 colorectal, 4 breast, and 6 other cancers) by a DNA synthesis (3H‐thymidine incorporation) inhibition assay. PT and MN from the same patient showed heterogeneity in chemosensitivity. MN were more sensitive to the agents than PT. PT were sensitive to 5‐FU, whereas MN were sensitive to CDDP. An analysis of the sensitivity correlations showed that the sensitivities of PT to MMC, 5‐FU, CQ, and CDDP correlated with each other, but ADR sensitivity correlated with only CQ sensitivity. The sensitivities of MN correlated with each other, except for those to ADR and CDDP. In contrast, MMC, ADR, or CQ sensitivity showed a correlation between PT and MN. These results suggest that patients should be treated according to the sensitivity of the target lesion. However, if the sensitivity assay is not avilable, the sensitivity correlation may be useful when choosing the agent. It also may be important that ADR sensitivity does not correlate with the sensitivities of other agents.

A phase II study of 5-fluorouracil, cisplatin, and 4'-epirubicin in the treatment of advanced solid cancers.

This phase II study was designed to assess the therapeutic potential of intensive course treatment with three anticancer agents: 50 mg of cisplatin on day 1, 40 mg/m2 of epirubicin on day 2, and 250 mg of 5-fluorouracil on days 2 through 5. Drug courses were repeated every 2 weeks and most patients received between 4 and 6 courses. Thirty-five patients with measurable advanced solid cancers entered the study. They consisted of 16 gastric, 5 colorectal, 4 gallbladder, 3 pancreatic, 3 lung, 2 esophageal, 1 uterine, and 1 ovarian cancers. Of the 35 patients, 29 were evaluated for therapeutic effect of the regimen, and the overall response rate was 31.0% (5 CR + 4 PR/29). A 33.3% rate of tumor regression, consisting of 2 complete responses (CR) and 3 partial responses (PR) out of 15 patients (2 CR + 3 PR/15), was seen for gastric cancers. For the other types of tumors the responses were achieved in 2 lung cancers (1 CR + 1 PR/3), 1 uterine cancer (1 CR/1), and 1 ovarian cancer (1 CR/1). The esophageal. colorectal, pancreatic, and gallbladder cancers were unresponsive to this regimen. Toxicities of the drug treatment were clinically tolerable and consisted of general malaise, nausea, vomiting, stomatitis, alopecia, and leucopenia. However, two patients died of uncontrollable metabolic acidosis after 1 and 2 courses, respectively. This intensive course treatment appears to promote the regression of gastric, lung, and gynecologic cancers.

In vivo effects of human recombinant tumor necrosis factor alone and in combination with other biological response modifiers on human digestive organ cancer xenografts transplanted in nude mice

The present study was designed to evaluate the effect of rTNF alone or in combination with other BRMs on human digestive organ cancers. Six kinds of human digestive organ cancer xenografts (esophageal, stomach, colonic, pancreatic, bile duct, and liver cancers: EC-YO, GC-YN, CC-KK, PC-HN, BDC-SN and Li-7, respectively) were transplanted in nude mice, and rTNF was administered at 103, 5 × 103, or 104U/head directly into the tumor 3 times a week for 2 weeks. EC-YO was the most sensitive to rTNF, and intratumoral administration of rTNF at 103 U/head caused tumor regression. PC-HN, CC-KK and GC-YN were relatively sensitive to rTNF, and their growth was significantly inhibited by rTNF at 5 × 103 U/head, however, the tumors regrew after treatment. Li-7 and BDC-SN were resistant to rTNF. The effects of rTNF in combination with recombinant interferon-γ (rIFN-γ), recombinant interleukin-2 (rIL-2), or streptococcal preparation OK-432 were assessed in mice transplanted with GC-YN. All combinations of rTNF at 5 × 103 U/head and other BRMs were more effective than rTNF alone, and GC-YN tumors were completely regressed after treatment with a combination of rTNF and rIFN-γ or rTNF and OK-432. However in all cases, the combination of rTNF at 103 U/head and any other BRM did not improve the effect. Furthermore, the adverse effects of the combinations were more serious than those of rTNF alone.TNF may still be a useful cytokine, because it can induce the regression of tumors. However, for its clinical application, a method should be developed to reduce its side effects.

Comparative effects of a recombinant and a mutein type of granulocyte colony stimulating factor on the growth of Meth-A fibrosarcoma with 5-fluorouracil chemotherapy

The present study was designed to evaluate the effects of a recombinant human G-CSF (rhG-CSF) and a mutein G-CSF(KW-2228) on leucopenia and tumor growth in mice treated with 5-fluorouracil (5-FU). In normal mice, the number of leucocytes (white blood cell, WBC) reached the peak 12 hours after a single injection of either type of G-CSF and decreased to the normal level after 24 hours. Daily administration induced a continuous increase in the WBC count, however, administrations at intervals did not. Meth-A fibrosarcoma was subcutaneously inoculated into the backs of syngeneic BALB/c mice. The mice were treated with 5-FU alone or with G-CSFs. Chemotherapy with 5-FU alone resulted in leucopenia and an insignificant inhibition of tumor growth. The conjunctive administration of G-CSFs with 5-FU resulted in a significantly augmented inhibition of tumor growth, and leukopenia was not seen. This augmenting effect was more prominent with KW-2228.These results suggest that in 5-FU chemotherapy G-CSFs may be beneficial in restoring the number of leucocytes from leucopenic state and in augmenting the tumor inhibitory effect. Furthermore, KW-2228 may be more beneficial than the natural type rhG-CSF.

Low Uracil Concentration in the Liver might be Responsible for the Decreased Antineoplastic Activity of Fluoropyrimidines in Mice with CCl4-Induced Chronic Liver Dysfunction

Some fluoropyrimidines are considered to be metabolized in liver microsomes. The present study was designed to assess the effect of chronic liver dysfunction on the antineoplastic activity of fluoropyrimidines. Chronic liver dysfunction was induced in BALB/c mice by 8 weeks of CCl4 injections. The 5-fluorouracil (5-FU)-sensitive MOPC-104E and 5-FU-resistant Meth-A cells were inoculated subcutaneously into the mice and then various fluoropyrimidines were administered intragastrically. The antitumor activity of the fluoropyrimidines decreased in mice with chronic liver dysfunction, although the concentration of 5-FU in the tumor of normal mice did not differ from that of mice with liver dysfunction. However, the concentration of uracil in the liver was decreased in mice with chronic liver dysfunction. On the other hand, the percent conversion of Tegafur [1-(2-tetrahydrofuryl)-5-FU] to 5-FU in the normal liver did not differ from that in the dysfunctional liver. These results suggest that low uracil concentrations in the liver may result from chronic liver dysfunction and lead to decreased antitumor efficacy of fluoropyrimidines.