瘤内注射戊二醛治疗小鼠移植性肿瘤的实验观察

目的：通过瘤内注射戊二醛（Glutar）治疗小鼠移植性肿瘤，探讨戊二醛抗瘤效应。方法：将32只小鼠随机平分为四组。接种H22小鼠肝癌细胞株。7天后依照分组移植瘤内注射2％戊二醛、无水乙醇、丝裂霉素。结果：给药7天移植瘤体积：戊二醛、乙醇、丝裂霉素组均小于对照组（P＜0．05）。戊二醛组值最小，病理见瘤细胞坏死。21天后小鼠生存：戊二醛组（5／8）高于对照组（2／8）。结论：戊二醛瘤内注射能够起到抑制肿瘤增长，延缓荷瘤鼠生存的作用。     

顺铂脂质体腹腔注射对S180荷瘤小鼠的治疗作用

目的 探讨顺铂脂质体腹腔注射对S180荷瘤小鼠的抗肿瘤作用.方法 采用昆明种小鼠腹腔内注射S180细胞形成腹水瘤模型,40只小鼠肿瘤种植24 h后随机分为4组,分别为生理盐水组、空白脂质体组、顺铂注射液组、顺铂脂质体组,分别给予生理盐水、空白脂质体、顺铂注射液和顺铂脂质体腹腔注射,共给药4次,给药时间间隔72 h.结果...     

瘤内注射戊二醛治疗小鼠移植性肿瘤的实验观察

通过瘤内注射戊二醛治疗小鼠移植性肿瘤探讨戊二醛抗瘤效应。方法：将３２只小鼠随机平分为四组。接种Ｈ２２小鼠肝癌细胞株。７天后依照分组移植瘤内注射２％戊二醛，无水乙醇，丝裂霉素。结果：给药７天移植瘤体积：戊二醛、乙醇，丝裂霉素组均小于对照组。戊二醛组值最小，病理见瘤细胞坏死。２１天后小鼠生存：戊二醛组高于对照组。结论：戊二醛瘤内注射能够起到抑制肿瘤增长，延缓鼠生存的作用。     

中人氟安局部植入治疗小鼠乳腺癌的实验北大核心CSCD

目的研究氟尿嘧啶(5-Fu)缓释植入剂对乳腺癌移植瘤的治疗效果。方法将50只乳腺癌荷瘤小鼠随机分为5组,每组10只。A、B组于瘤旁植入5-Fu缓释植入剂,剂量分别为200和100 mg/kg;C组于瘤旁注射5-Fu注射液,剂量为200 mg/kg,D组于腹腔内注射5-Fu注射液200 mg/kg;E组不予任何治疗,为空白对照组。分别于给药后0、3、6、9和12 d观察荷瘤小鼠生存情况、体质量变化及肿瘤体积,12天后处死所有小鼠,称瘤重,计算抑瘤率,绘制肿瘤生长曲线,完整剥离瘤块经福尔马林浸泡固定后制作石蜡切片进行免疫组织化学观察肿瘤细胞HER2表达情况。结果 (1)A、B组肿瘤生长曲线平缓,12天后A、B、C及D组抑瘤率分别为50.43%,41.64%,27.57%和22.87%;(2)A、B组肿瘤体积与C、D组比较,差异有统计学意义(P<0.05);(3)氟尿嘧啶(5-Fu)缓释植入剂瘤周植入组ErbB2表达率明显低于对照组,差异有统计学意义(P<0.05)。结论 5-Fu缓释植入剂于瘤旁植入能安全有效地抑制乳腺癌的生长。     

益气清毒方联合CTX对H22肝癌小鼠抑瘤实验研究及机制探讨

[目的]观察益气清毒方联合环磷酰胺(CTX)的抗肿瘤效果并探讨其作用机制。[方法]水煎煮制备益气清毒方汤剂,建立H22荷瘤小鼠动物模型,接种后第2d开始给药,腹腔注射CTX及益气清毒方灌胃,第9d称重后处死小鼠,眼眶取血做血液学检查,并观察小鼠胸腺、脾脏及肿瘤瘤体生长情况。[结果]与CTX低剂量组相比,CTX+益气清毒方高、中剂量组小鼠胸腺指数明显增加,瘤重下降,白细胞及血小板计数无明显下降。[结论]益气清毒方能明显加强CTX的抗肿瘤作用,抑制H22荷瘤小鼠肿瘤生长,减轻CTX不良反应,提高免疫功能。     

茶多酚干预移植性S180小鼠肿瘤血管相关因子表达

[目的]应用免疫组化法，观察茶多酚口服、静脉与局部注射三种给药途径对移植性小鼠血管内皮生长因子（VEGF）、金属蛋白酶组织抑制因子Ⅱ（TIMP-2）表达影响，进行茶多酚抗肿瘤新生血管生成研究。[方法]建立移植性S180小鼠肿瘤动物模型，随机分茶多酚口服灌胃、局部注射、腹腔注射、人参皂苷Rg3口服灌胃、CTX腹腔注射对照、生理盐水肿瘤模型对照、正常空白对照7组，5组后取肿瘤组织，石蜡包埋、切片，免疫组化染色观察VEGF、TIMP-2表达。[结果]茶多酚口服及局部注射组可明显降低S180荷瘤VEGF表达水平、增加TIMP-2表达水平。[结论]茶多酚口服、局部注射具有抗肿瘤新生血管生成作用。     

重组溶瘤单纯疱疹病毒oHSV2 治疗结直肠癌的实验研究

  目的  评估重组溶瘤单纯疱疹病毒oHSV2在CT26结肠癌荷瘤小鼠中的抗肿瘤效果,初步探讨其治疗机制。  方法  构建CT26细胞荷瘤小鼠肿瘤模型。1）小鼠瘤内注射oHSV2,ELISA法测定血清中粒细胞-巨噬细胞集落刺激因子（granulocyte-macro-phage colony-stimulating factor,GM-CSF）浓度;2）荷瘤小鼠分为oHSV2组、5-氟尿嘧啶（5-FU）组（阳性对照组）、磷酸盐缓冲液（PBS）组（阴性对照组）。给药后,记录小鼠体质量、肿瘤体积、生存期及生活状态等变化,评估病毒抗肿瘤效果;3）流式细胞术定量检测肿瘤引流淋巴结（tumor-draining lymphnode,TDLN）内树突状细胞（dendritic cell,DC）及瘤体内CD4+T与CD8+T的比例。  结果  1）瘤内注射oHSV2后,血清中的GM-CSF浓度不断升高。首次给药后第8 天出现高峰（3150±327.1）pg/mL,后缓慢下降;2）相比PBS组,oHSV2和5-FU组均表现出显著的抗肿瘤效果,小鼠生存期显著延长（50 d vs. 36 d,P＜0.01;51 d vs. 36 d,P＜0.01）,但oHSV2治疗未引起小鼠体质量下降。治疗起始第28天,5-FU组平均体质量较PBS组有显著性差异（16.61 g vs. 22.07 g,P＜0.01）,oHSV2组与PBS组差异无统计学意义（P>0.05）,且小鼠病毒注射区皮肤无坏死、溃疡;3）流式分析结果显示相比PBS组,oHSV2治疗组的DC（6.49% vs. 3.73%,P＜0.01）,CD4+T（15% vs. 8.57%,P＜0.01）与CD8+T（8.19% vs. 5.15%,P＜0.01）比例升高。而5-FU组各细胞比例较PBS组明显降低（P＜0.05）。  结论  瘤内注射oHSV2有效抑制结直肠癌细胞生长,病毒治疗与化疗药物相比不伴有明显的毒副反应。病毒在荷瘤小鼠体内复制产生具有生物活性的GM-CSF,可增强抗肿瘤免疫。      

131I标记抗CD20单克隆抗体在荷瘤裸鼠体内动态分布的实验研究

目的:探讨131I-anti-CD20 McAb经瘤内注射后在荷人Burkitts淋巴瘤细胞系Raji细胞移植瘤裸鼠体内的动态分布。方法:131I标记物的标记采用IODO-GEN碘化标记;注射标记物后第1、3、7、15天将荷瘤裸鼠活杀,定标器测量并计算瘤组织、血液等12种器官或组织的瘤/非瘤(T/NT)比值以及%ID/g值(每克组织摄入注入量的百分数)。结果:131I-anti-CD20 McAb瘤内注射组血液及其他组织器官T/NT比值在给药后第1、3和7天均显著高于腹腔注射组和131I-IgG瘤内注射组(P<0.05);该组肿瘤%ID/g值在给药后第1、3和7天分别为后两组的1.4~17倍和1.7~3.7倍;各非瘤组织和器官的%ID/g值低于后两组。结论:131I-anti-CD20 McAb经瘤内途径给药可以使肿瘤获得最高的放射性药物摄取率和最高的瘤/非瘤组织放射性药物摄取比,为下一步运用该途径进行放射免疫治疗提供了实验依据。     

瘤内局部注射重组人血管内皮抑制素对小鼠Lewis肺癌抑瘤作用的研究

目的探讨瘤内直接注射重组人血管内皮抑制素（恩度）联合腹腔注射顺铂对Lewis肺癌的抑制效果。方法成功建立小鼠Lewis肺癌移植瘤模型。按体质量将小鼠随机分为生理盐水组、顺铂组、瘤内注射恩度组、顺铂联合腹腔注射恩度组、顺铂联合瘤内注射恩度组5组。治疗后处死小鼠,计算肿瘤体积抑瘤率,用免疫组织化学法测定各组小鼠肿瘤组织血管内皮生长因子（VEGF）的表达水平及微血管密度（microvessel density,MVD）。结果顺铂组、瘤内注射恩度组、顺铂联合腹腔注射恩度组、顺铂联合瘤内注射恩度组的抑瘤率分别为61.8%、24.9%、70.3%、74.3%。免疫组织化学结果显示,顺铂联合瘤内注射恩度组的VEGF表达及MVD计数在各实验组中均最低,与顺铂联合腹腔注射恩度组比较两者差异均有统计学意义（均P〈0.05）。结论经皮穿刺瘤内注射恩度联合顺铂有协同抗肿瘤作用,能有效抑制肺癌的生长及转移,并且相同剂量的恩度,肿瘤内局部注射效果优于腹腔注射。     

不同时期应用细胞瘤苗对红白血病荷瘤小鼠抗瘤作用的研究

目的：探讨不同时间应用细菌瘤苗对红细胞病荷瘤小鼠的抗瘤作用。方法：在不同时间内应用瘤苗免疫治疗红白血病荷瘤小鼠，观察小鼠生存期，皮下肿瘤大小及肿瘤，注射部位病理变化。结果：3天，7天瘤苗治疗的小鼠生存期延长，皮下肿瘤生长缓慢，病理可见瘤组织坏死及大量以单个核细胞为主的炎细胞浸润，与PBS组及10天瘤苗组相比，有显著性差异。结论：3天，7天瘤苗比10天瘤苗组抗肿瘤作用强。     

Combination therapy of an orthotopic renal cell carcinoma model using intratumoral vector-mediated costimulation and systemic interleukin-2.

PURPOSE: Interleukin (IL)-2 therapy is currently used for therapy of renal cell carcinoma (RCC). However, it is only effective in approximately 10% to 15% of patients, showing a need for additional therapies. We have previously described a replication-defective fowlpox vector encoding three costimulatory molecules (B7-1, ICAM-1, and LFA-3), designated rF-TRICOM. Here, we show that intratumoral administration of rF-TRICOM in an orthotopic RCC model effectively enhances tumor immunogenicity and reduces tumor burden in mice and the combination of rF-TRICOM and IL-2 is more effective than either therapy alone. EXPERIMENTAL DESIGN: RCC cells were implanted under the capsule of the kidney, and mice were given rF-TRICOM intratumorally 14 days later. We compared the effect of rF-TRICOM, rF-granulocyte macrophage colony-stimulating factor (GM-CSF), and two doses of IL-2 and combinations of the above on antitumor efficacy and survival. Host CD4(+) and CD8(+) T-cell responses were also evaluated. RESULTS: The results show that (a) systemic IL-2 therapy was moderately effective in the reduction of tumor burden in an orthotopic RCC model; (b) a single intratumoral injection of rF-TRICOM and rF-GM-CSF significantly reduced tumor burden; (c) the addition of systemic IL-2 to intratumoral rF-TRICOM/rF-GM-CSF administration resulted in further reduction of tumor burden, decrease in the incidence of metastasis, and extended survival in tumor-bearing mice above that seen with either treatment alone; and (d) CD8(+) T cells played a critical role in the antitumor effect seen with rF-TRICOM/rF-GM-CSF + IL-2 therapy. Finally, the addition of systemic recombinant IL-15 or intratumoral vector-delivered IL-15 to intratumoral rF-TRICOM/rF-GM-CSF administration resulted in substantially more tumor-free mice than either therapy alone. CONCLUSIONS: These studies show that intratumoral administration of rF-TRICOM admixed with rF-GM-CSF is effective at reducing tumor burden in mice and the addition of IL-2 further contributes to this effect. These studies thus form the rationale for combination immunotherapy clinical trials in patients with RCC.     

Radiosensitization by intratumoral administration of cisplatin in a sustained-release drug delivery system.

PURPOSE: Effects of combining local irradiation and intratumoral (i.t.) administration of cisplatin (CDDP) in a sustained-release drug delivery system (epi gel) were studied in a murine SCCVII squamous cell carcinoma model in mice. MATERIALS AND METHODS: The epinephrine injectable gel was used as a drug delivery system. Intratumoral pharmacokinetics of CDDP was studied by using 195mPt-CDDP. The tumor volume quadrupling time (TVQT) and tumor growth delay (TGD) time were used to evaluate the antitumor efficacy of treatment regimens. RESULTS: The concentration and residence of 195mPt-CDDP was significantly higher in tumors treated with 195mpt-CDDP/epi gel than in tumors treated with 195mPt CDDP gel or 195mPt-CDDP suspension. Intratumoral administration of CDDP/epi gel (4 mg/kg) produced an average TGD time of 15.5 +/- 2.8 days, which was 5.2 - 7.4 times longer than CDDP suspension i.t. or i.p. When combined with a single dose of radiation (10 Gy), i.t. administration of CDDP/epi gel was 2.0 - 3.6-fold as effective as administered i.t. in suspension (39.2 +/- 4.1 vs. 19.8 +/- 3.9 days of TGD, P < 0.05) or i.p. in solution (39.2 +/- 4.1 vs. 11.0 +/- 1.6 days, P < 0.001) in inhibiting tumor growth and produced 20-60% complete remission of tumors. When combined with fractionated irradiation, pre-irradiation CDDP administration was more effective than post-radiation administration (26.7 vs. 12.1 days of TGD, P < 0.05). Mice treated with CDDP/epi gel i.t. alone or in combination with irradiation, had little systemic toxicity. CONCLUSIONS: Intratumoral administration of CDDP using the sustained-release drug delivery system is an efficient and safe method to maximize the drug concentration in tumor, minimize the systemic toxicity and enhance antitumor efficacy of irradiation.     

In situ tumor vaccination with interleukin-12-encapsulated biodegradable microspheres: induction of tumor regression and potent antitumor immunity

An alternative technology for the local and sustained delivery of cytokines to tumors for cancer immunotherapy was evaluated and shown here to induce tumor regression, suppression of metastasis, and development of systemic antitumor immunity. Treatment of tumor-bearing BALB/c mice with a single intratumoral injection of biodegradable polylactic acid microspheres loaded with recombinant interleukin-12 (IL-12) promoted complete regression of the primary tumor and prevented the metastatic spread to the lung. Mice that experienced tumor regression after being treated rejected a subsequent challenge with live tumor cells, which indicated the development of systemic antitumor immunity. In situ tumor vaccination, ie., injection of IL-12 microspheres into existing tumors, was superior to vaccination of mice with mixtures of tumor cells (live or irradiated) and IL-12 microspheres in inducing systemic antitumor immunity. The sustained release of IL-12 from the microspheres was superior to bolus injection of free IL-12, and intratumoral delivery of microspheres was more effective than other routes of administration. These studies establish the utility of biodegradable polymer microspheres as a clinically feasible alternative to systemic cytokine therapy and cytokine gene-modified cell vaccines for the treatment of neoplastic disease.     

Antitumor effect of intratumoral administration of bone marrow-derived dendritic cells transduced with wild-type p53 gene.

PURPOSE: Dendritic cells (DCs) are attractive effectors for cancer immunotherapy because of their potential to function as professional antigen-presenting cells for initiating cellular immune responses. The tumor suppressor gene p53 is pivotal in the regulation of apoptosis, and approximately 50% of human malignancies exhibit mutation and aberrant expression of p53. We investigated the antitumor effect of intratumoral administration of bone marrow-derived dendritic cells transduced with wild-type p53 gene. EXPERIMENTAL DESIGN: We examined whether intratumoral administration of DCs infected with recombinant adenovirus expressing murine wild-type p53 (Ad-mp53) could induce systemic antitumor responses against mutant p53-expressing tumors, highly immunogenic MethA, or weakly immunogenic MCA-207 implanted in syngeneic mice. RESULTS: Accumulation of wild-type p53 protein in bone marrow-derived murine DCs could be successfully achieved by Ad-mp53 infection. Treatment with intratumoral injection of Ad-mp53-transduced DCs caused a marked reduction in the in vivo growth of established MethA and MCA-207 tumors with massive cellular infiltrates. Administration of p53-expressing DCs suppressed the growth of both injected MCA-207 tumors and untreated distant MCA-207 tumors, but not unrelated Lewis lung carcinoma tumors, suggesting the augmentation of systemic immunogenicity against MCA-207 tumor cells. Moreover, intratumoral injection of p53-expressing DCs had a greater antitumor effect than did s.c. immunization. CONCLUSIONS: Our results indicate that intratumoral administration of DCs expressing murine wild-type p53 leads to significant systemic immune responses and potent antitumor effects in mutant p53-expressing murine cancer models. These findings raise the possibility of using this strategy of intratumoral injection of p53-expressing DCs for human cancer treatment.     

Administration route‐dependent induction of antitumor immunity by interferon‐alpha gene transfer

Type I interferon (IFN) protein is a cytokine with pleiotropic biological functions that include induction of apoptosis, inhibition of angiogenesis, and immunomodulation. We have demonstrated that intratumoral injection of an IFN‐α‐expressing adenovirus effectively induces cell death of cancer cells and elicits a systemic tumor‐specific immunity in several animal models. On the other hand, reports demonstrated that an elevation of IFN in the serum following an intramuscular delivery of a vector is able to activate antitumor immunity. In this study, we compared the intratumoral and systemic routes of IFN gene transfer with regard to the effect and safety of the treatment. Intratumoral injection of an IFN‐α adenovirus effectively activated tumor‐responsive lymphocytes and caused tumor suppression not only in the gene‐transduced tumors but also in distant tumors, which was more effective than the intravenous administration of the same vector. The expression of co‐stimulatory molecules on CD11c⁺ cells isolated from regional lymph nodes was enhanced by IFN gene transfer into the tumors. Systemic toxicity such as an elevation of hepatic enzymes was much lower in mice treated by intratumoral gene transfer than in those treated by systemic gene transfer. Our data suggest that the intratumoral route of the IFN vector is superior to intravenous administration, due to the effective induction of antitumor immunity and the lower toxicity. (Cancer Sci 2010)     

Antitumor activity of the intratumoral injection of fowlpox vectors expressing a triad of costimulatory molecules and granulocyte/macrophage colony stimulating factor in mesothelioma

Deficiency in costimulatory molecule expression has been implicated in the ability of tumors to escape immune effectors. The activity of the intratumoral administration of recombinant fowlpox vectors expressing a triad of costimulatory molecules (rF-TRICOM) was evaluated in the asbestos-induced AB12 and AC29 mouse models of mesothelioma. Mesothelioma cell infected with rF-TRICOM expressed high levels of the costimulatory molecules. Prolongation of survival was observed in mice receiving rF-TRICOM in AB12 and AC29 intraperitoneal models. Complete tumor regressions were observed in mice receiving intratumoral rF-TRICOM in the AB12 subcutaneous tumor model. Tumor regressions were associated with the development of serum IgG reactivities to mesothelioma-associated determinants and specific systemic cytolytic activity, and responding mice were capable of rejecting tumors upon re-challenge. Antitumor activity was also observed in mice with established AB12 tumor vaccinated with irradiated rF-TRICOM-infected AB12 cells. The antitumor activity of intratumoral rF-TRICOM was superior to that of the intratumoral injection of a fowlpox vector expressing granulocyte-macrophage colony stimulating factor (rF-GM-CSF). AB12 and AC29 tumors were found to produce GM-CSF and to have substantial macrophage infiltration. Production of GM-CSF decreased in vivo in tumors injected with rF-TRICOM. rF-TRICOM and wild-type fowlpox inhibited the growth of AB12 and AC29 cells in vitro; less inhibition was observed with rF-GM-CSF. These results indicate that the intratumoral injection of rF-TRICOM has significant activity in mouse models of mesothelioma and can elicit a systemic antitumor immune response. The results also suggest potential limitations to the intratumoral administration of cytokines, such as GM-CSF, in mesothelioma.     

Enhancement of antitumor effect by intratumoral administration of bax gene in combination with anticancer drugs in gastric cancer

Proapototic gene is an important target to enhance the chemotherapeutic effect in cancer cells. Based on in vitro study showing that the introduction of bax gene enhanced the sensitivity to anticancer drugs, we examined whether the intratumoral administration of bax gene could enhance the anti-tumor effect in combination with anticancer drugs in gastric cancer. The human gastric cancer cell line, MKN45 was transplanted into nude mice, and the intratumoral administration of bax gene was performed using the bax cDNA plasmid complexed with a cationic lipopolyamine. The enhancement of antitumor effect was examined in the combination with 5-fluorouracil (5-FU) and cisplatin (CDDP). The anticancer drugs were administered intraperitoneally with one third of LD50 four times at 4-day intervals, and the antitumor effect was assessed by the NCI protocol. The expression of bax gene was analyzed by RT-PCR and the apoptotic cell death was assessed by TUNEL method. The intratumoral administration of bax gene alone showed slight anti-tumor effect as compared to that of control tumor injected with vector alone. The antitumor effect of 5-FU and CDDP was significantly enhanced in the combination with intra-tumoral administration of bax gene as compared to that of CDDP and 5-FU alone (p<0.05, Student's t-test). The enhancement of antitumor effect was associated with the constitutive overexpression of bax gene and with the induction of apoptosis in the tumor treated with anticancer drug and bax gene. These results indicate that the combination therapy of intratumoral administration of bax gene complexed with a cationic lipopolyamine and anticancer drugs may provide us a new strategy for cancer chemotherapy to enhance its therapeutic efficacy in gastric cancer as termed with gene-chemotherapy.     

Antitumor effect of PSK at a distant site: inductions of interleukin-8-like factor and macrophage chemotactic factor in murine tumor

The antitumor effect of PSK, a Coriolus preparation, at a distant site was analyzed with the use of a double grafted tumor system in which male BALB/c mice received simultaneous intradermal inoculations of Meth-A tumor in the right (10(6) cells) and the left (2 x 10(5) cells) flanks and were then injected with PSK in the right tumor on the third day thereafter. The antitumor effect of intratumoral administration of PSK in the right tumor on days 3, 4 and 5 was compared with the effect of surgical resection of the right tumor on day 5. Three out of 8 mice given PSK intratumorally became tumor-free whereas no mouse tumor-free in the left flank was found among the surgically resected mice. As regards sinecomitant immunity, tumor inoculation into the right flank followed by intra-tumoral administration of PSK on days 3 and 5 and surgical excision of the primary tumor on day 6 resulted in complete rejection of a tumor challenge in the left flank on day 21. The combination of presurgical intratumoral injections of PSK (more than 2 times) and postoperative oral administration of PSK appeared to be most effective in eradicating secondary tumors. Isolated TILs (tumor-infiltrating lymphocytes), obtained from the right tumor (treated with PSK) and the left tumor on day 10 in the double grafted tumor system were cultured in RPMI1640 with 10% fetal calf serum for 24 h. The culture supernatants were harvested and tested for the presence of chemotactic activity for neutrophils or macrophages. Significant neutrophil chemotactic factor (NCF) and macrophage chemotactic factor (MCF) activities were detected in the culture media from PSK-treated TILs that had been cultured for 24 h. Neither significant neutrophil nor macrophage chemotactic activity was detected in the media from untreated TILs. NCF and MCF activities were also detected in the culture supernatant from PSK-treated tumor tissue on day 6. PSK-induced NCF in the murine tumor was neutralized by treatment with anti-human IL-8 IgG, and might be murine IL-8-like factor. Therefore, neutrophil and macrophage infiltrations of tumors following intratumoral injections of PSK are probably mediated by inductions of IL-8-like factor and MCF.     

Antitumor Effect of PSK at a Distant Site: Inductions of Interleukin-8-like Factor and Macrophage Chemotactic Factor in Murine Tumor

The antitumor effect of PSK, a Coriolus preparation, at a distant site was analyzed with the use of a double grafted tumor system in which male BALB/c mice received simultaneous intradermal inoculations of Meth-A tumor in the right (10⁶ cells) and the left (2 × 10⁵ cells) flanks and were then injected with PSK in the right tumor on the third day thereafter. The antitumor effect of intratumoral administration of PSK in the right tumor on days 3, 4 and 5 was compared with the effect of surgical resection of the right tumor on day 5. Three out of 8 mice given PSK intratumorally became tumor-free whereas no mouse tumor-free in the left flank was found among the surgically resected mice. As regards sinecomitant immunity, tumor inoculation into the right flank followed by intratumoral administration of PSK on days 3 and 5 and surgical excision of the primary tumor on day 6 resulted in complete rejection of a tumor challenge in the left flank on day 21. The combination of presurgical intratumoral injections of PSK (more than 2 times) and postoperative oral administration of PSK appeared to be most effective in eradicating secondary tumors. Isolated TILs (tumor-infiltrating lymphocytes), obtained from the right tumor (treated with PSK) and the left tumor on day 10 in the double grafted tumor system were cultured in RPMI1640 with 10% fetal calf serum for 24 h. The culture supernatants were harvested and tested for the presence of chemotactic activity for neutrophils or macrophages. Significant neutrophil chemotactic factor (NCF) and macrophage chemotactic factor (MCF) activities were detected in the culture media from PSK-treated TILs that had been cultured for 24 h. Neither significant neutrophil nor macrophage chemotactic activity was detected in the media from untreated TILs. NCF and MCF activities were also detected in the culture supernatant from PSK-treated tumor tissue on day 6. PSK-induced NCF in the murine tumor was neutralized by treatment with anti-human IL-8 IgG, and might be murine IL-8-like factor. Therefore, neutrophil and macrophage infiltrations of tumors following intratumoral injections of PSK are probably mediated by inductions of IL-8-like factor and MCF.     

Antitumor Effect of PSK at a Distant Site: Tumor-specific Immunity and Combination with Other Chemotherapeutic Agents

The antitumor effect of PSK, a Coriolus preparation, was analyzed with the double grafted tumor system in which BALB/c mice received intradermal inoculations of syngeneic Meth-A fibrosarcoma in the right (primary tumor, 10⁵ cells) and left (distant tumor, 2 × 10⁵ cells) flanks. Intratumoral administration of PSK significantly inhibited the growth of not only the right but also the left tumor. PSK also inhibited the growth of a methylcholanthrene-induced fibrosarcoma BAMC-1, and a methylurethane-induced adenocarcinoma Colon 26 in the double grafted tumor system of syngeneic BALB/c mice. However, when the left distant tumor was different from the right Meth-A tumor, the intratumoral administration of PSK in the right tumor was unable to inhibit the growth of the left' BAMC-1 or RL♂ -1 tumor. The PSK-induced immunity, therefore, is tumor-specific and T lymphocytes may play an important role in antitumor memory function. The enhancement of concomitant immunity by PSK treatment was completely impaired by previous intravenous administration of an alkylating agent, cyclophosphamide (CY). The enhancement of sinecomitant immunity by PSK treatment was also impaired by previous CY intravenous administration. The antitumor effect of PSK was suppressed by previous intravenous administration of another alkylating agent, ACNU. It is possible that alkylating agents suppress the function of effector T cells and granulocytes which are very important for the antitumor immune cascade reaction due to PSK treatment. On the other hand, the antitumor effect of PSK was enhanced by previous intravenous administration of an anti-metabolite, 5-fluorouraeil.