Immunomodulatory Effects of Radiofrequency Ablation in a Breast Cancer Model

Radiofrequency ablation (RFA), a minimally invasive surgical procedure has an increasing application in the surgical treatment of tumors. Data indicate that RFA might stimulate anti-cancer immunity possibly through the induction of necrosis and heat shock proteins (HSP) expression. This study tests a hypothesis that RFA leads to bidirectional immunoregulation. Experimental rat breast tumors were treated with RFA, surgical excision or sham operation. RFA resulted in the highest NK cells infiltration, increased HSP70 expression and activation of caspase-3 enzyme in the tumor margins. A significant reduction of the circulatory regulatory T (Treg) cells was found in both RFA- and excision-treated rats, although less pronounced in the RFA-group. The splenocyte proliferation to tumor cell lysate was stronger in the RFA-treated rats in comparison with untreated tumor-bearing rats. The potential role of self-HSP for immunomodulation was examined using in vitro proliferation assay to tetanus toxoid using human peripheral leukocytes. The response to the tetanus toxoid was significantly suppressed by HSP90 plus auto-antibodies versus HSP90 or auto-antibodies alone. In conclusion, RFA reduced the circulatory Tregs although not as efficient as tumor excision. HSPs plus natural antibodies suppress the anti-tumor response probably by stimulating Tregs. Therefore, RFA may play a role in anti-cancer therapy if combined with Tregs suppression.     

Deposition of complement proteins on cells treated by photodynamic therapy in vitro.

Activation of the complement system has emerged as a critical event in the response of tumors to photodynamic therapy (PDT) due to its involvement in the vascular effects as well as in the inflammatory and immune reactions observed with this treatment modality. However, the exact mechanism of PDT-induced complement activation has not been precisely characterized. The present study examines the potential of PDT at the cellular level to directly activate the complement system. Mouse tumor SCCVII cells treated by Photofrin-based PDT and post-incubated in the presence of homologous (mouse) serum were analyzed by flow cytometry for binding of complement proteins on their surface. The results show that PDT induced the fixation of complement C3 protein, probably in the form of its activated fragments, and of the terminal membrane attacks complex of complement on the treated SCCVII cells. Deposition of C3/C3 fragments on human umbilical vein endothelial cells (HUVEC) treated by Photofrin-PDT and post-incubated in the presence of human serum was also detected. Complement fixation was preferentially elevated on SCCVII cell undergoing PDT-induced apoptosis. The induction of surface expression of heat shock protein 70 (HSP70) on PDT-treated cells also triggered complement deposition, since the presence of anti-HSP70 antibodies during the post-PDT incubation blocked the anchoring of C3/C3 fragments to SCCVII cells. The fact that PDT-treated cells are recognized by the complement system as their target adds an important element for understanding the mechanism of tumor response to PDT.     

Message in a bottle: role of the 70-kDa heat shock protein family in anti-tumor immunity

Extracellular heat shock protein 70 (HSP70) is a potent agent for tumor immunotherapy, which can break tolerance to tumor-associated antigens and cause specific tumor cell killing by cytotoxic CD8+ T cells. The pro-immune effects of extracellular HSP70 are, to some extent, extensions of its molecular properties as an intracellular stress protein. The HSP70 are characterized by massive inducibility after stress, preventing cell death by inhibiting aggregation of cell proteins and directly antagonizing multiple cell death pathways. HSP70 family members possess a domain in the C terminus that chaperones unfolded proteins and peptides, and a N-terminal ATPase domain that controls the opening and closing of the peptide binding domain. These properties not only enable intracellular HSP70 to inhibit tumor apoptosis, but also promote formation of stable complexes with cytoplasmic tumor antigens that can then escape intact from dying cells to interact with antigen-processing cells (APC) and stimulate anti-tumor immunity. HSP70 may be released from tumors undergoing therapy at high local extracellular concentrations, and send a danger signal to the host leading to APC activation. Extracellular HSP70 bind to high-affinity receptors on APC, leading to activation of maturation and re-presentation of the peptide antigen cargo of HSP70 by the APC. The ability of HSP70-peptide complexes (HSP70-PC) to break tolerance and cause tumor regression employs these dual properties as signaling ligand and antigen transporter. HSP70-PC thus coordinately activate innate immune responses and deliver antigens for re-presentation by MHC class I and II molecules on the APC cell surface, leading to specific anti-tumor immunity.     

Optimizing heat shock protein expression induced by prostate cancer laser therapy through predictive computational models

Thermal therapy efficacy can be diminished due to heat shock protein (HSP) induction in regions of a tumor where temperatures are insufficient to coagulate proteins. HSP expression enhances tumor cell viability and imparts resistance to chemotherapy and radiation treatments, which are generally employed in conjunction with hyperthermia. Therefore, an understanding of the thermally induced HSP expression within the targeted tumor must be incorporated into the treatment plan to optimize the thermal dose delivery and permit prediction of the overall tissue response. A treatment planning computational model capable of predicting the temperature, HSP27 and HSP70 expression, and damage fraction distributions associated with laser heating in healthy prostate tissue and tumors is presented. Measured thermally induced HSP27 and HSP70 expression kinetics and injury data for normal and cancerous prostate cells and prostate tumors are employed to create the first HSP expression predictive model and formulate an Arrhenius damage model. The correlation coefficients between measured and model predicted temperature, HSP27, and HSP70 were 0.98, 0.99, and 0.99, respectively, confirming the accuracy of the model. Utilization of the treatment planning model in the design of prostate cancer thermal therapies can enable optimization of the treatment outcome by controlling HSP expression and injury.     

光动力疗法治疗肿瘤的免疫机制研究进展

光动力疗法(photodynamic therapy,PDT)是治疗肿瘤的有效手段之一,PDT治疗可导致肿瘤细胞的死亡和凋亡,并损伤肿瘤相关血管.近年来,PDT的免疫机制越来越受到关注.肿瘤细胞的免疫逃逸是肿瘤发生发展的重要因素.PDT治疗肿瘤时,可通过免疫原性细胞死亡(immunogenic cell death,ICD)诱导肿瘤细胞表达损伤相关分子模式(damage associated molecular patterns,DAMPs),从而活化树突状细胞,诱导机体特异性抗肿瘤免疫.同时,PDT还可影响肿瘤微环境中的相关免疫细胞和因子,进而增强机体抗肿瘤反应.光动力治疗和其他免疫治疗联合应用亦能增强疗效.故光动力治疗的免疫机制研究将为肿瘤治疗提供可能的新思路.     

Comparison of the anti-tumor effects of various whole-body hyperthermia protocols: correlation with HSP 70 expression and composition of splenic lymphocytes

Whole-body hyperthermia (WBH) has been used as an adjunct approach to radio-/chemotherapy for tumor therapy for many years. However, the molecular mechanism underlying the enhancement of tumor control is not clearly understood. It has been hypothesized that WBH might activate immune system by inducing the expression of heat shock proteins (HSPs), which are thought to facilitate the presentation of tumor-specific antigens. In the present work, we examined the effects of various thermal doses of WBH on tumor growth delay and HSP70 levels in tumors on C57BL/6 mice, as well as on splenic lymphocyte subpopulations. The maximal WBH effect (about 40% decrease in tumor weight) was achieved by a 2-hour WBH treatment everyday at 40.0°C. By using this treatment schedule, the populations of CD3⁺/CD4⁺ T cells and CD3⁺/CD8⁺ T cells increased by 4 and 3 times, respectively, at the end of WBH treatment period. When the length of day-by-day WBH treatment was longer than 2 hours or the frequency of WBH treatment was lower than once a day, the effect of tumor growth delay and the population of CD3⁺ T lymphocyte in spleen increase were discounted. On the other hand, the HSP70 levels in tumor nodules rose continuously as the WBH treating time increased, but the populations of NK cells in spleen did not change significantly. The results suggest that an increased CD3⁺ T lymphocyte population is closely related to the anti-tumor effect of WBH, which might be a useful marker for effectiveness of hyperthermia. However, neither the levels of HSP70 nor the NK cell populations in spleen appear to correlate to tumor control.     

热休克蛋白70融合肿瘤抗原基因的DNA疫苗研究进展

在抗肿瘤免疫治疗中,已经发展了多种形式的热休克蛋白70(HSP70)相关治疗性疫苗,这些疫苗主要包括蛋白疫苗、肽疫苗、细胞疫苗及DNA疫苗等,其中HSP70融合DNA疫苗凭借其自身的优势引起人们的关注。它不但可诱导高效、持久的抗肿瘤免疫应答,而且可以维持免疫记忆。本文就HSP70在肿瘤治疗性DNA疫苗中的作用和应用作一综述。     

Anti-PD-1 synergizes with cyclophosphamide to induce potent anti-tumor vaccine effects through novel mechanisms

Programmed death-1 receptor (PD-1) is expressed on T cells following TCR activation. Binding of this receptor to its cognate ligands, programmed death ligand (PDL)-1 and PDL-2, down-regulates signals by the TCR, promoting T-cell anergy and apoptosis, thus leading to immune suppression. Here, we find that using an anti-PD-1 antibody (CT-011) with Treg-cell depletion by low-dose cyclophosphamide (CPM), combined with a tumor vaccine, induces synergistic antigen-specific immune responses and reveals novel activities of each agent in this combination. This strategy led to complete regression of established tumors in a significant percentage of treated animals, with survival prolongation. We show for the first time that combining CT-011 and CPM significantly increases the number of vaccine-induced tumor-infiltrating CD8(+) T cells, with simultaneous decrease in infiltrating Treg cells. Interestingly, we find that CT-011 prolongs Treg-cell inhibition induced by CPM, leading to a sustainable significant synergistic decrease of splenic and tumor-infiltrated Treg cells. Surprisingly, we find that the anti-tumor effect elicited by the combination of CT-011 and CPM is dependent on both CD8(+) and CD4(+) T-cell responses, although the antigen we used is a class I MHC-restricted peptide. Thus, we describe a novel and effective therapeutic approach by combining multiple strategies to target several tumor-mediated immune inhibitory mechanisms.     

The immunological consequences of photodynamic treatment of cancer,a literature review

In this review we discuss the effect of photodynamic treatment (PDT) of solid tumors on the immune response. The effect on both the innate and adapted immune response is discussed. We have summarized the evidence that PDT causes or enhances an anti-tumor response. PDT is a local treatment in which the treated tumor remains in situ while the immune system is only locally affected and still functional in contrast with e.g. after systemic chemotherapy. We conclude that PDT of cancer is a way of in situ vaccination to induce a systemic antitumor response. In general, immune cells are found in the tumor stroma, separated from tumor cells by extracellular matrix and basal membrane-like structures. We hypothesize that PDT destroys the structure of a tumor, thereby enabling direct interaction between immune cells and tumor cells resulting in the systemic anti-tumor immune response.     

肿瘤热休克蛋白70联合IL-2对荷瘤小鼠的治疗作用

目的:研究肿瘤热休克蛋白70(HSP70)与IL-2联合应用对荷瘤小鼠的治疗作用。方法:用液相色谱法纯化小鼠肿瘤细胞 株中的HSP70。对纯化产物用SDS-PAGE及Western blot进行定性分析,再用毛细管电泳鉴定其纯度。通过动物实验,观察HSP70与IL-2单独应用及联合应用的抗肿瘤作用。结果:HSP70与IL-2联合应用较单独应用的治疗效果更明显,但治疗作用仍以HSP70为主。单独应用IL-2只能延长小鼠的生存期限[平均为(36.6±13.0)d],而HSP70 10μg组可使40％荷瘤小鼠的肿瘤最终全部消退,生存期最长者>90[平均生存期(>59.2±29.6)d],与对照组相比较差异显著(P<0.01)。HSP70与IL-2联合应用组可使60％荷瘤小鼠的肿瘤完全消退,平均生存期(>70.8±26.5)d,与对照组相比差异十分显著(P<0.01)。结论:合适剂量的HSP70与IL-2联合应用,对荷瘤小鼠有明显的治疗作用,可明显抑制肿瘤进展,提高生存率。以上结果对研究人类恶性肿瘤的免疫治疗具有较大的参考价值。     

Hypericin induced death receptor-mediated apoptosis in photoactivated tumor cells

Nasopharyngeal carcinoma (NPC) is a malignant disease of the head/neck region with a 5-year survival level of approximately 65%. To explore the novel therapeutic strategies in the management of this disease, the potential effects of photodynamic therapy (PDT) in NPC cells were investigated. PDT, a new mode of treatment, is based on the combined use of light-absorbing compounds and light irradiation. Two human NPC cells such as, poorly differentiated (NPC/CNE2) and moderately differentiated (NPC/TW0-1) and other types of tumor cells like colon (CCL-220.1) and bladder (SD) undergo rapid apoptosis when treated with PDT sensitized with hypericin (HY). It has been shown that this compound has a strong photodynamic effect on tumors and viruses. However, the initiating events of PDT sensitized HY-induced apoptosis are not identified completely. In this study, we sought to determine whether Fas/FasL upregulation and involvement of mitochondrial events are an early event in HY-treated PDT induced apoptosis. Loss of mitochondrial transmembrane potential, release of cytochrome c, involvement of caspases 8 and 3 and the status caspase-3 specific substrate PARP, were evaluated in PDT treated tumor cells. Photosensitization of HY enhanced both CD95/CD95L expression and induced CD95-signaling dependent cell death in all tumor cell lines studied. CD95/CD95L expression appeared within 2 h following light irradiation and appeared to be a principal event in PDT induced apoptosis. Furthermore, these results indicate that release of mitochondrial cytochrome c into the cytoplasm within 2-3 h post PDT is a secondary event following the activation of initiator caspase-8 preceding Apaf-1, caspase-9 and caspase-3 activation, cleavage of PARP and DNA fragmentation.     

Therapeutic Antitumor Efficacy of Cancer Stem Cell-Derived DRibble Vaccine on Colorectal Carcinoma

Dendritic cell (DC)-based immunotherapy has been a promising strategy for colon cancer therapy, but the efficacy of dendritic cell vaccines is in part limited by immunogenicity of loaded antigens. In this study, we aimed to identify a putative tumor antigen that can generate or enhance anti-tumor immune responses against colon cancer. CD44⁺ colon cancer stem cells (CCSCs) were isolated from mouse colorectal carcinoma CT-26 cell cultures and induced to form defective ribosomal products-containing autophagosome-rich blebs (DRibbles) by treatment with rapamycin, bortezomib, and ammonium chloride. DRibbles were characterized by western blot and transmission electron microscopy. DCs generated from the mice bone marrow monocytes were cocultured with DRibbles, then surface markers of DCs were analyzed by flow cytometry. Meanwhile, the efficacy of DRibble-DCs was examined in vivo. Our results showed that CCSC-derived DRibbles upregulated CD80, CD86, major histocompatibility complex (MHC)-I, and MHC-II on DCs and induced proliferation of mouse splenic lymphocytes and CD8⁺ T cells. In a model of colorectal carcinoma using BALB/c mice with robust tumor growth and mortality, DC vaccine pulsed with CCSC-derived DRibbles suppressed tumor growth and extended survival. A lactate dehydrogenase test indicated a strong cytolytic activity of cytotoxic T-cells derived from mice vaccinated with CCSC-derived DRibbles against CT-26 cells. Furthermore, flow cytometry analyses showed that the percentages of IFN-γ-producing CD8⁺ T-cells were increased in SD-DC group compare with the other groups. These findings provide a rationale for novel immunotherapeutic anti-tumor approaches based on DRibbles derived from colon cancer stem cells.     

榄香烯复合瘤苗的HSP70表达及其主动免疫预防效应

为进一步阐明本室专利榄香烯复合瘤苗(EC-TCV)的主动免疫效应与其HSP70-肿瘤肽之间的关系,本文以42℃热休克(H)为对照,首先检测了榄香烯(E)、丝裂霉素C(MMC)、戊二醛(G)单独或复合处理时对小鼠HCa-F肝癌、L615白血病细胞膜HSP(HSP70、HSP90)表达的影响,发现只有膜HSP70的表达在两种榄香烯复合瘤苗中均升高,随后以E-MMC复合处理的HCa-F细胞中提纯的HSP70-肿瘤肽(HHSP70)为免疫原,以小鼠HCa-F肝癌细胞为模型,研究了HHSP70的主动免疫预防效应及其特异性。结果表明,E、MMC、G同H相似,也具有应激原作用,能诱导应激蛋白HSP70的表达;而且HSP70在HCa-F和L615两种肿瘤细胞均以E-MMC-G三者复合处理时为最高;HHSP70能诱发机体产生主动抗瘤效应,且这种效应有一定的肿瘤特异性。     

TLR4 is essential for dendritic cell activation and anti-tumor T-cell response enhancement by DAMPs released from chemically stressed cancer cells

The combination of immunotherapy and chemotherapy is regarded as a promising approach for the treatment of certain types of cancer. However, the underlying mechanisms need to be fully investigated to guide the design of more efficient protocols for cancer chemoimmunotherapy. It is well known that danger-associated molecular patterns （DAMPs） can activate immune cells, including dendritic cells （DCs）, via Toll-like receptors （TLRs）; however, the role of DAMPs released from chemical drug-treated tumor cells in the activation of the immune response needs to be further elucidated. Here, we found that colorectal cancer （CRC） cells treated with oxaliplatin （OXA） and/or 5-fluorouracil （5-Fu） released high levels of high-mobility group box 1 （HMGB1） and heat shock protein 70 （HSP70）. After OXA/5-Fu therapy, the sera of CRC patients also exhibited increased levels of HMGB1 and HSP70, both of which are well-known DAMPs. The supernatants of dying CRC cells treated with OXA/5-Fu promoted mouse and human DC maturation, with upregulation of HLA-DR, CD80 and CD86 expression and enhancement of IL-lp, TNF-a, MIP-la, MIP-lp, RANTES and IP-IO production. Vaccines composed of DCs pulsed with the supernatants of chemically stressed CRC cells induced a more significant IFN-y-producing Thl response both in vitroand in vivo. However, the supernatants of chemically stressed CRC cells failed to induce phenotypic maturation and cytokine production in TLR4-deficient DCs, indicating an essential role of TLR4 in DAMP-induced DC maturation and activation. Furthermore, pulsing with the supernatants of chemically stressed CRC cells did not efficiently induce an IFN-y-producing Thl response in TLR4-deficient DCs. Collectively, these results demonstrate that DAMPs released from chemically stressed cancer cells can activate DCs viaTLR4 and enhance the induction of an anti-tumor T-cell immune response, delineating a clinically relevant immuno-adjuvant pathway triggered by DAMPs.     

Heat shock fusion protein induces both specific and nonspecific anti-tumor immunity

Mucin 1 (MUC1) is a tumor antigen, and the most important epitopes that can induce cytotoxic T lymphocytes (CTL) reside in the variable-number tandem repeats (VNTR). Heat shock protein (HSP) complexes isolated from tumors have been shown to induce specific anti-tumor immunity. HSP alone can also induce nonspecific immunity. To explore the possibility to utilize the specific anti-tumor immunity induced by MUC1 VNTR and the nonspecific immunity induced by HSP, we constructed a recombinant protein (HSP65-MUC1) by fusing Bacillus Calmette-Guérin-derived HSP65 with the MUC1 VNTR peptide and tested its ability to induce anti-tumor activities in a tumor challenge model. The growth of MUC1-expressing tumors was significantly inhibited in mice immunized with HSP65-MUC1, both before and after tumor challenge. A much larger percentage of immunized mice survived the tumor challenge than non-immunized mice. Correlating with the anti-tumor activity, HSP65-MUC1 was shown to induce MUC1-specific CTL as well as nonspecific anti-tumor immunity. In the human system, HSP65-MUC1-loaded human DC induced the generation of autologous MUC1-specific CTL in vitro. These results suggest that exogenously applied HSP65-MUC1 may be used to treat MUC1 tumors by inducing the epitope-specific CTL as well as nonspecific anti-tumor responses mediated by the HSP part of the fusion protein.     

可溶性PD-1协同HSP70-肽复合物抑制荷瘤小鼠肝癌的研究

目的 :研究基因转染和表达的可溶性PD 1(solubleprogrammeddeath 1,sPD 1)对HSP70 肽疫苗抗肿瘤效果的影响及协同机制。方法 :以HSP70 肽疫苗免疫BALB/c小鼠后 ,用半定量RT PCR技术检测和分析HSP70 肽疫苗对小鼠脾细胞上PD 1及其配体基因表达的影响。体内转染表达sPD 1,用MTT比色法检测HSP70 肽疫苗免疫小鼠对肿瘤生长的抑制作用以及脾淋巴细胞的细胞毒活性。结果 :单独的sPD 1就有抗肿瘤效应。HSP70 肽疫苗不仅能预先在动物体内诱导肿瘤特异性的CTL ,而且可使脾细胞上抑制性共刺激受体PD 1及其配体的表达显著升高。用sPD 1与HSP70 肽疫苗联合治疗荷瘤小鼠 ,能提高脾CTL的杀伤效率并延长HSP70 肽疫苗的免疫效果。结论 :sPD 1可通过阻断PD 1与其配体的结合作用 ,及减弱PD 1的负反馈抑制作用 ,而增强HSP70 肽疫苗的抗肿瘤效应     

Poly (γ-glutamic acid) based combination of water-insoluble paclitaxel and TLR7 agonist for chemo-immunotherapy

Advanced anti-cancer regimens are being introduced for more effective cancer treatment with improved life expectancy. In this research, immuno-stimulating agent toll-like receptor-7 (TLR-7) agonist-imiquimod and low dose chemotherapeutic agent-paclitaxel were synergized to demonstrate tumor therapy along with anti-tumor memory effect. Both therapeutic agents being water insoluble were dispersed in water with the help of water soluble polymer: poly (γ-glutamic acid) (γ-PGA) using a co-solvent systems leading to formation of micro-dispersions of drugs. Paclitaxel and imiquimod formed crystalline microstructures in the size range of 2–3 μm and were stably dispersed in γ-PGA matrix for more than 6 months. Paclitaxel and combination of paclitaxel and imiquimod had significant tumor killing effect in-vitro on various tumor cell lines, while antigen presenting cells (dendritic cells-DCs) treated with the same concentration of imiquimod along with the combination led to enhanced proliferation (250%). In DCs, enhanced secretion of pro-inflammatory and Th1 cytokines was observed in cells co-treated with paclitaxel and imiquimod dispersed in γ-PGA. When administered by intra-tumoral injection in mouse melanoma tumor model, the treatment with combination exemplified drastic inhibition of tumor growth leading to 70% survival as compared to individual components with 0% survival at day 41. The anti-tumor response generated was also found to have systemic memory response since the vaccinated mice significantly deferred secondary tumor development at distant site 6 weeks after treatment. The relative number and activation status of DCs in-vivo was found to be dramatically increased in case of mice treated with combination. The dramatic inhibition of tumor treated with combination is expected to be mediated by both chemotherapeutic killing of tumor cells followed by uptake of released antigen by the DCs and due to enhanced proliferation and activation of the DCs.     

Heat shock protein-antigen fusions lose their enhanced immunostimulatory capacity after endotoxin depletion

Heat shock proteins (HSPs) induce cross-presentation of antigens by dendritic cells (DC) as well as DC maturation. These properties make HSP antigen complexes good candidates to prime CD8 T cell responses against tumor-associated antigens. In this study, we analyzed four different members of the HSP70 family fused to a fragment of ovalbumin (OVA) as a model tumor antigen. E. coli-derived recombinant HSP70-OVA fusion proteins efficiently primed antigen-specific cytotoxic T cells in short-term in vivo immunization assays. Because of concerns that the adjuvant effect of HSPs may be due to endotoxin contamination, we studied this issue in detail. Induction of OVA-specific cytotoxicity was significantly decreased in mice deficient for the LPS receptor, TLR4. After careful removal of endotoxins, immunization with HSP70-OVA failed to prime cytotoxic T cell responses. However, we obtained strong in vivo kill responses when endotoxin-depleted HSP70-OVA was used in combination with the TLR9 ligand CpG oligodeoxynucleotide 1668. Importantly, prophylactic and therapeutic treatment with endotoxin-depleted HSP70-OVA together with CpG significantly delayed the outgrowth of OVA-expressing B16 melanoma cells. However, we were unable to detect significant differences in the magnitudes of immune responses against endotoxin-depleted recombinant OVA vs. endotoxin-depleted HSP70-OVA fusion protein. Thus, immunization with recombinant HSP70-antigen fusion protein does not provide an advantage over recombinant antigen alone when combined with a suitable adjuvant. Altogether, our data suggest that the adjuvant effect of the HSP70 part of the fusion protein is completely lost after endotoxin removal.     

吐温80合并温热对B16黑色素瘤细胞hsp 70、c-fos、泛蛋白及S-100蛋白表达的影响

目的:研究吐温80与温热合并的协同抗肿瘤机理及与凋亡的关系.方法:用免疫组化方法.观察吐温80合并41℃温热作用后即时、4小时和72小时,B16肿瘤细胞热休克蛋白70(hsp 70)、c-fos、泛蛋白以及S-100蛋白表达的改变,并进行定量分析.结果:hsp70和C-fos蛋白呈中等阳性反应,分别位于B16细胞的胞质和胞核;泛蛋白为弱阳性、S-100蛋白呈强阳性,分布于胞质;41℃ 60分钟作用可增强hsp70表达.以4小时为显著.核亦呈阳性反应;对其它蛋白表达无明显影响;吐温80单独可轻度抑制hsp70表达;温热与吐温80合并作用能显著抑制hsp70表达,c-fos和泛蛋白表达则明显增加.S-100蛋白变化各组无显著意义.结论:吐温80增强温热抗肿瘤的效应可能与其抑制hsp70合成.影响细胞热耐受性的产生和诱导细胞调亡有关.