Non-antibody immunotherapy of cancer

Bacillus Calmette-Guérin in the management of superficial bladder cancer

Intravesical Bacillus Calmette-Guérin (BCG) is the mainstay of superficial bladder cancer treatment. We performed a literature search through Medline/Pubmed using key words 'Bacillus Calmette-Guérin', 'intravesical', 'bladder neoplasm' and 'immunotherapy' for published data in the English language from 1970 to 2007 to review the current status of intravesical therapy and practice recommendations. The exact mechanism of action of intravesical BCG is yet to be elucidated. However, it appears that it is mediated by the local immune response, mainly through T-helper cell response. It reduces the recurrence rate by an average of 40% and progression by more than 20% in papillary tumors over the patients without BCG therapy. However, progression prevention is seen only in series which have used maintenance therapy at least for one year. It is effective in CIS of bladder with a response rate of more than 40% and prevention of progression in one-fourth patients. Most acceptable dose, induction treatment and maintenance therapy protocols are discussed. However, these are yet to be confirmed in large randomized trials. Intravesical BCG is well tolerated in most of the patients with mild to moderate side-effects in induction therapy; however, most patients do not complete maintenance therapy due to side-effects which is the most common concern at the present time.

Intravesical interleukin-15 gene therapy in an orthotopic bladder cancer model

Interleukin-15 (IL-15) is known to stimulate the proliferation of CD8(+) T-cells and natural killer cells, and also to help to maintain memory CD8(+) T cells, suggesting that it may be of value in cytokine treatment of bladder cancer. In this experiment, we tested the efficiency of intravesical liposomal IL-15 gene delivery and its antitumor effect in a mouse orthotopic bladder cancer model. We established an orthotopic bladder cancer model by implanting 5×10(5) MBT-2 cells into female C3H/HeN mice through the urethra. The mice received repeated intravesical gene delivery injected with liposome-mediated plasmids (5 μg) transurethrally. On day 23, the bladder weights in the group receiving medium alone, the beta-galactosidase gene delivery control group, and the IL-15 gene therapy group were 196±36 mg, 201±35 mg, and 96±29 mg, respectively (p<0.05), demonstrating the antitumor effect of intravesical IL-15 gene therapy in this model. In the bladders treated with IL-15 gene plasmid instillation, histological analysis revealed that many inflammatory cells were induced around the tumors. Immunohistochemical analysis confirmed that there was predominant infiltration of CD8(+) T cells around the tumor nest. After the intravesical IL-15 gene therapy, the growth of rechallenged subcutaneous MBT-2 cells in surviving mice was inhibited again via tumor-specific cytotoxic T lymphocytes, although newly implanted FM3A cells in the same mice were not rejected. The present findings indicate that IL-15 gene therapy may be a promising new adjuvant therapy for bladder cancer.

T-cell coregulatory molecule expression in urothelial cell carcinoma: clinicopathologic correlations and association with survival

PURPOSE

Aberrant expression of T-cell coregulatory molecules has been investigated as a mechanism by which certain cancers may evade host immune surveillance. We evaluated expression of the T-cell coregulators B7-H1, B7-H3, and PD-1 in urothelial cell carcinoma (UCC) of the bladder.

EXPERIMENTAL DESIGN

Immunohistochemistry for B7-H1, B7-H3, and PD-1 was done on paraffin-embedded sections from 318 consecutive patients with UCC who underwent radical cystectomy. Expression was correlated with clinicopathologic outcomes and postoperative survival.

RESULTS

B7-H3 was widely expressed in UCC, as 222 of 314 (70.7%) tumors showed positive staining. Expression of B7-H3 in UCC was significantly increased compared with adjacent, nontumor urothelium, as a median of 70% of tumor cells expressed B7-H3, compared with 20% of cells in nontumor specimens (P < 0.001). The increase in B7-H3 expression was independent of tumor stage (P = 0.13). Expression of B7-H1 by UCC tumors (P < 0.001) and PD-1 by tumor-infiltrating lymphocytes (P = 0.012) were significantly associated with increased pathologic stage. Patients who had received intravesical bacillus Calmette-Guerin before cystectomy tended to show increased expression of B7-H3 (P = 0.023) and PD-1 (P = 0.071) but were less likely to express B7-H1 (P = 0.027). Moreover, for the subset of patients with organ-confined disease (n = 167), B7-H1 expression independently predicted all-cause mortality after cystectomy (hazard ratio, 3.18; 95% confidence interval, 1.74-5.79; P < 0.001).

CONCLUSIONS

B7-H3 is highly expressed in UCC across tumor stages, whereas B7-H1 and PD-1 expression are associated with advanced disease. B7-H1 expression predicts mortality after cystectomy for patients with organ-confined tumors. These molecules may represent novel diagnostic or prognostic markers, as well as therapeutic targets, for patients with UCC.

The safety and efficacy of different doses of bacillus Calmette Guérin in superficial bladder transitional cell carcinoma

OBJECTIVES

To conduct a trial using three different doses of bacillus Calmette-Guérin (BCG) to determine whether lowering the dose of BCG could reduce toxicity without compromising its efficacy in the treatment of superficial bladder cancer.

METHODS

From July 2002 to June 2005, 152 patients with superficial bladder cancer entered the trial. The patients were randomized to receive three different doses of BCG: 40, 80, and 120 mg. There were no significant differences in clinical and pathologic characteristics among the three groups. Twenty-four patients could not be followed to the end of the study because of poor compliance. At completion of the study, 40 patients could be evaluated in group A (40 mg), 48 in group B (80 mg), and 40 in group C (120 mg).

RESULTS

After treatment patients were evaluated for a mean follow-up period of 36 months (range 18 to 52 months). No significant difference in recurrence rate (20% versus 25% versus 20% respectively; P >0.05) was observed among the groups, and no progression of the disease was seen. Significant differences were observed among groups A, B, and C in local toxicity (30% versus 41.7% versus 70%, respectively; P <0.01). Systemic toxicity was more common in group C compared with groups B and A (P <0.01).

CONCLUSIONS

Reduction in the dose of intravesical BCG can reduce the toxicity associated with the treatment of superficial bladder cancer without affecting the efficacy of therapy.

Wirkmechanismen der intravesikalen BCG-Immuntherapie des oberflächlichen Harnblasenkarzinoms

Immunotherapy for treatment of solid cancer mostly is an experimental treatment. In contrast, intravesical immunotherapy of superficial bladder cancer with bacille Calmette-Guérin (BCG) is clinically well established and accepted worldwide because of better results compared to topical chemotherapy. BCG is currently regarded as the most successful immunotherapy of cancer. Unfortunately the mechanism of action has not yet been fully clarified. This article gives an overview on the complex research on the mechanisms of actionhighly successful therapy.

Intravesical interleukin-12 gene therapy in an orthotopic bladder cancer model

OBJECTIVES

To evaluate the antitumor effect of intravesical cationic liposome-mediated interleukin-12 (IL-12) gene delivery in an orthotopic murine bladder cancer model, and to investigate the immunologic memory against tumors between IL-12 gene therapy and bacille Calmette-Guérin (BCG) therapy.

METHODS

Orthotopic murine bladder tumors were established by implanting 5 x 10(5) MBT-2 cells into the bladder of syngeneic female C3H mice. Intravesical IL-12 gene therapy was evaluated at varying doses: 0 microg (control) and 3, 5, and 10 microg (n = 8 for each group). Intravesical treatments were performed every 3 days and repeated six times beginning 5 days after tumor implantation. To compare the long-term, tumor-specific immunity between IL-12-treated mice (n = 18) and BCG-treated mice (n = 20), the animals surviving at day 60 and 10 new control mice were rechallenged with MBT-2 cells and received no additional treatment. On day 120, all surviving mice were killed and underwent necropsy.

RESULTS

In the IL-12 groups at doses of 0, 3, 5, and 10 microg, 0, 2, 3, and 3 mice survived, respectively. Mice in the 5-microg and 10-microg IL-12 groups survived significantly longer than did the control group. All mice cured by IL-12 treatment successfully rejected the rechallenge with MBT-2 cells; however, mice cured by BCG and the new control mice died of the rechallenged bladder tumors.

CONCLUSIONS

Intravesical IL-12 gene therapy, which induced long-lasting tumor-specific immunologic memory compared with BCG therapy, improved survival in an orthotopic bladder cancer model.

Immune mechanisms in bacillus Calmette-Guerin immunotherapy for superficial bladder cancer

PURPOSE

Of all medical disciplines it is exclusively in urology in which immunotherapy for cancer has an established position today with intravesical bacillus Calmette-Guerin (BCG) against superficial bladder carcinoma recurrences. BCG is regarded as the most successful immunotherapy to date. However, the mode of action has not yet been fully elucidated. We provide a thorough overview of this complex field of research.

MATERIALS AND METHODS

Rather than simply reporting all experimental data available for better understanding the involved immune mechanisms, we chose to provide comprehensively only information supported by several independent pathways of evidence.

RESULTS

Major findings made during the last few years include systematic analyses of patient material, detailed in vitro studies and investigations in animal models, which have led to a substantially greater understanding of the mechanisms involved.

CONCLUSIONS

The efficacy of BCG is based on a complex and long lasting local immune activation. The bladder as a confined compartment, in which high local concentrations of the immunotherapy agent and effective recruitment of immune cells can be achieved, serves as an ideal target organ for this type of immunotherapy approach.

Reduction of side effects of intravesical therapy with bacille Calmette-Guérin by pentoxifylline?--an in vitro approach

Immunotherapy with intravesical bacille Calmette-Guérin (BCG) is the treatment of choice against superficial bladder cancer recurrences. However, this therapy is associated with side effects that are considered to be the result of inflammatory cytokines. Since pentoxifylline is known to interfere with the production of cytokines, this drug was tested in vitro with regard to a later clinical application in BCG-treated patients. The cytokine release and the cytotoxicity of interleukin-2 or BCG-stimulated mononuclear cells were analyzed, and the growth of BCG under the influence of pentoxifylline was assayed. The results showed an inhibition of cytokine release of stimulated mononuclear cells. The cytotoxicity of BCG-stimulated mononuclear cells but not of lymphokine-stimulated mononuclear cells against bladder carcinoma cells was significantly inhibited. Restimulation with fresh BCG restored cytotoxicity. Direct coincubation of BCG and pentoxifylline resulted in a reduction of mycobacterial metabolism. From these data, we conclude that the use of pentoxifylline to reduce BCG-related side effects should be tested further in a clinical study.

The role of cytotoxic T-lymphocytes in the prevention and immune surveillance of tumors--lessons from normal and immunodeficient mice

The idea of immunological surveillance against cancer has existed for nearly 100 years but as no conclusive evidence has yet been published the importance of the cellular immune defense in the detection and removal of incipient or existing tumors is still a hotly debated subject. However, in order to select a relevant immunotherapeutic strategy in the treatment of cancer, a fundamental understanding of the basic immunologic conditions under which a tumor develops and exists is a prerequisite. Therefore, a murine model was set up that we hoped would enable us to confirm or reject the theory of immunological surveillance. A large panel of methylcholanthrene induced tumors was established in T-cell immunodeficient nude mice and congenic normal mice to study the influence of the immune system on developing tumors. As nude mice developed tumors fastest and with the highest incidence, we concluded that in this model the immune system constituted a 'tumor-suppressive factor' delaying and sometimes abrogating tumor growth, i.e. performing immune surveillance. Immunogenicity of the tumors was assessed by transplantation back to normal histocompatible mice. Tumors originating from the immunodeficient nude mice turned out to be far more immunogenic than tumors from normal mice, resulting in a high rejection rate. CD8+ cytotoxic T cells were found to be indispensable for this rejection, leading to the conclusion that the cytotoxic T cells perform immune selection in normal mice, eliminating immunogenic tumor cell variants in the incipient tumor. In this review, we discuss the difficulties facing immunotherapy when conclusions are drawn from the presented observations and hypotheses.

Bacillus-Calmette-Guérin (BCG) and 3D tumors: an in vitro model for the study of adhesion and invasion

PURPOSE

To study adhesion, penetration and internalization of BCG and effector-cells to and into three-dimensional in vitro cell aggregates from benign and malignant urothelial origin mimicking small in vitro tumors.

MATERIALS AND METHODS

Multicellular spheroids (MCS) were generated by "liquid-overlay" technique. Adhesion and penetration of viable FITC-labelled BCG into MCS from urothelial cancer cell lines and normal urothelial cells was studied by electron microscopy (TEM) and fluorescence microscopy. Spheroid growth during BCG-co-incubation was determined by light microscopy. Peripheral blood mononuclear cells (PBMC) were stimulated with BCG to generate BCG-activated-killer (BAK) cells. The infiltration of these effectors and of lymphokine-activated killer (LAK) cells into MCS was examined at different intervals by means of immunohistochemistry. The resulting cytotoxicity was judged in a 3H-l-methionine release assay.

RESULTS

BCG adhered to MCS from tumor cells but not to benign cell MCS. Intracellular internalization of the bacteria was detectable in superficial tumor cell-layers (1-5) whereas BCG was not found in deeper layers. Proliferation of malignant MCS was reduced in the presence of BCG. Benign MCS showed contact inhibition growth arrest, which was not altered by BCG. BAK and LAK effector cells both infiltrated tumor cell MCS as opposed to unstimulated PBMC. In contrast to LAK cells, BAK cells did not infiltrate into benign cell MCS and were not cytotoxic towards them.

CONCLUSION

With regard to the clinical situation the selective adhesion and internalization of BCG to malignant cells might explain why BCG has been rarely found in follow-up biopsies in tumor free patients. More interestingly, the selective adhesion of BCG to and infiltration of BAK effector cells into malignant cell spheroids suggests a selective mode of action of BCG.

Loss of tumorigenicity and increased immunogenicity induced by interleukin-10 gene transfer in B16 melanoma cells

Because interleukin-10 (IL-10) has potent immunosuppressive and anti-inflammatory properties and is produced by some cancers, we hypothesized that its production might play a role in carcinogenesis by inhibiting adequate antitumoral immune responses. To test this hypothesis, retroviral vectors containing the IL-10 cDNA were generated and used to infect B16F1 melanoma cells that were injected subcutaneously in syngeneic mice. Surprisingly, IL-10 gene transfer resulted in a loss of tumorigenicity that was proportional to the amount of IL-10 secreted. Histological analysis showed massive area of necrosis of these tumor cells, with infiltration of polymorphic inflammatory cells. Parental cells simultaneously implanted had decreased tumorigenicity only when mixed with IL10-producing cells, but not when injected contralaterally, suggesting that their eradication is mediated mostly by a local phenomenon. Host T lymphocytes and natural killer (NK) cells were involved in this eradication because IL-10-producing cells grew in nude mice and in CD8+ or NK-depleted mice. Finally, mice injected with IL-10-secreting cells developed an antitumoral systemic immune response able to protect them against a subsequent challenge with parental cells. These results demonstrate that, in some settings, IL10 may have in vivo immunostimulating and proinflammatory properties that need to be considered in its therapeutic development.

Mitogenic stimulation of human lymphocytes mediated by a cell surface elastase

A ca. 45-kDa protein which was recently identified and purified to homogeneity from a solid tumor cell line as a T-cell mitogen was found to have significant sequence similarities with human monocyte/neutrophil elastase inhibitor (EI) [1]. Since EI is a known substrate for elastase, a determination of whether a cell surface expressed elastase-like molecule might be the binding protein for this 45-kDa factor and mediate mitogenic signal transduction was undertaken. First, the surface of tumor infiltrating lymphocytes, TIL 660, the indicator cell line used for the purification of this mitogen, was shown to stain positively with an anti-elastase antibody using flow cytofluorometry for quantitation. Then, after observing an inverse correlation between cell surface staining and the proliferative status of the TILs, behavior which might be expected of a growth factor receptor upon activation, mitogenic signal transduction was attempted through the elastase-like molecules of the lymphocytes' plasma membrane with the anti-elastase antibody in the role of mitogen. A greater than 4-fold mitogenic stimulation was observed when this antibody was covalently linked to latex beads; in contrast, addition of the soluble form of the same antibody did not result in any increase in [3H]thymidine incorporation into the cells' DNA. Hence, these data support induced clustering of an elastase-like molecule on the lymphocyte surface as a mediator of mitogenesis and suggest that the binding protein for mitogenic signal transduction induced by the 45-kDa protein, a member of the serine protease inhibitor (serpin) superfamily of proteins, is a molecule with structure similar to a serine protease.

The induction of bacillus-Calmette-Guérin-activated killer cells requires the presence of monocytes and T-helper type-1 cells

Previously we have described the induction of MHC-unrestricted killer cells against bladder tumour cells by bacillus Calmette-Guérin (BCG), termed BCG-activated killer (BAK) cells. In the present paper we deal with the accessory-cell requirement for the activation of BAK cells. We show that monocytes are required for activating BAK cells, since no cytotoxicity can be induced in the absence of monocytes. Therefore, these phagocytes may represent the first step during the activation cascade of BAK cells. Furthermore, the presence of CD4+ T cells was essential for generating BAK cells: depleting peripheral blood mononuclear cells of CD4+ cells prior to stimulation with BCG abolished the cytotoxicity against bladder tumour cells. Experiments with monoclonal antibodies (mAb) neutralizing the activity of either interleukin-2 (IL-2) or interferon gamma (IFN gamma) underlined the importance of these cytokines: both mAb blocked the induction of BAK cells. Since both cytokines are related to the so-called Th1 pattern of T cells, we consider the second step of the generation of BAK cells as follows: monocytes presenting antigens of BCG trigger Th1-like cells in a preferred manner. These Th1-like T cells secrete IL-2 and IFN gamma and, thus, activate the BAK effector cells. Since CD4+ cells are dominant in the cells infiltrating the bladder wall after intravesical instillation of BCG in vivo, we postulate an important role for the Th1 subpopulation. We further postulate that the occurrence of macrophages in this infiltrate seems to be significant in the maintenance of the relapse-free state of the patient.

Bionutrition and oral cancer in humans

Tobacco (smoking and smokeless) use and excessive consumption of alcohol are considered the main risk factors for oral cancer (ICD9 140-149). Conspicuous national and international variations in oral cancer incidence and mortality rates, as well as observations in migrant populations, raise the possibility that diet and nutritional status could be an important etiologic factor in oral carcinogenesis. As shown in this report, abuse of alcohol and tobacco has serious nutritional implications for the host, and generates increased production of reactive free radicals as well as eliciting immunosuppression. Maintenance of optimal competence of the immune system is critical for cancer surveillance. Active oxygen species and other reactive free radicals mediate phenotypic and genotypic alterations that lead from mutation to neoplasia. Consequently, the most widely used chemopreventive agents against oral cancer (e.g., vitamins A, E, C, and beta-carotene) are anti-oxidants/free radical scavengers. These anti-oxidants, both natural and synthetic, neutralize metabolic products (including reactive oxygen species), interfere with activation of procarcinogens, prevent binding of carcinogens to DNA, inhibit chromosome aberrations, restrain replication of the transformed cell, suppress actions of cancer promoters, and may even induce regression of precancerous oral lesions such as leukoplakia and erythroplakia. Malnutrition is characterized by marked tissue depletion of anti-oxidant nutrients, including GSH (gamma-glutamyl-cysteinyl-glycine), a key cellular anti-oxidant as well as a modulator of T-cell activation. GSH or its precursor cysteine inhibits activation of the nuclear transcription factor kB(NFkB), and has been shown to be protective against chemically induced oral cancer and leukoplakia. Alcohol-, tobacco-, and/or malnutrition-induced immunosuppression promotes impaired salivary gland function and oral mucosal immunity, a prominent reduction in the number of helper CD4 cells with less marked changes in number of suppressor T-cells, and depressed NK cell activity, among others. These suggest a breakdown in capacity or the malnourished to mount effective tumor surveillance. This review article underscores the compounding but important roles of nutritional/dietary factors in the long-established causal link between abuse of alcohol and tobacco (smoking and smokeless) and oral cancer.