Anton B. Alexandroff

BCG immunotherapy of bladder cancer: 20 years on

1The situation is similar for most industrialised western nations, with incidence rates of 18 to 30 new cases per 10 0 000 men placing bladder cancer among the top five cancers in this sex. It is unclear why women are affected a third to a quarter less often than men. In 75% of patients the disease is diagnosed in its early superficial stage, usually as a result of gross or microscopic blood in the urine. However, with an overall 65% recurrence rate and 30% progression rate, even these patients need lifelong medical vigilance involving periodic internal inspections of their bladders. The cause of bladder cancer is unknown, but the disease has been strongly associated with exposure to certain aromatic chemicals, notably aniline dyes and benzidine compounds. Cigarette smoking with its release of -naphthalene and -napthalene into the urine is estimated to cause over one half of bladder cancers found in men and one third of those found in women. 2 Over 90% of bladder cancers found in such settings are of the transitional cell type, with squamous cell carcinoma usually occuring in patients with chronic infections such as bilhariasis. Among the transitional cell carcinomas, depth of penetration (stage) and degree of cellular anaplasia (grade) are the most important factors for prognosis. One particular mucosal high-grade lesion called carcinoma-in-situ is not surgically accessible because of its diffuse surface-spreading behaviour. Untreated carcinoma-in-situ will progress to muscleinvasive disease in about 80% of cases within 5 years. 3

Changes in urinary cytokines and soluble intercellular adhesion molecule-1 (ICAM-1) in bladder cancer patients after bacillus Calmette-Guérin (BCG) immunotherapy.

Intravesical immunotherapy for carcinoma in situ of the bladder is arguably the most effective form of tumour immunotherapy described to date. Following repeated instillations of BCG organisms into the bladder, large quantities of cytokines are detected in patients’ urine. This study concerns the production of IL‐1β, IL‐2, IL‐4, IL‐6, IL‐8, IL‐10, tumour necrosis factor‐alpha (TNF‐α), interferon‐gamma (IFN‐γ) and soluble ICAM‐1 (sICAM‐1) throughout the six weekly instillations which comprise a therapeutic course. Sequential instillations of BCG induced secretion of IL‐1β, IL‐2, IL‐6, IL‐8, IL‐10, TNF‐α, IFN‐γ and sICAM‐1 into urine. The responses were heterogeneous between patients and cytokines, but some general trends were evident. Although cytokine levels were initially low, their concentration increased with repeated instillation of BCG. Certain cytokines (e.g. IL‐6, IL‐8 and IL‐10) could be detected after the first instillation, whilst others (e.g. IL‐2 and IFN‐γ) were not detected until after the third or fourth instillation. Interestingly, IL‐4 was not detected, perhaps suggesting a differential effect on Th2‐like responses. Some patients produced particularly elevated or non‐detectable levels of cytokines, and a positive correlation was found between the production of various cytokines. The production of a particular cytokine did not correspond with lack of production of another species. Whether monitoring the production of cytokines following therapy may be of prognostic value will be determined in a larger series of patients. However, as these potent immunomodulators are thought t o be important for the 75% complete clinical response observed with BCG therapy, there remains the possibility that detection of the products of an activated immune system may correlate with eventual clinical outcome. This study is a necessary forerunner to full prognostic evaluation of such immunological data.

Role for CD40-CD40 ligand interactions in the immune response to solid tumours.

CD40-mediated interactions play an important role in the response to infections, transplantation, and cancer by affecting the development, activation, proliferation and differentiation of a variety of immune cells. In the current study we examined the role of CD40-mediated interactions in immune responses to bladder, pancreatic and breast carcinomas as well as melanoma cell lines using soluble human CD40L (rhCD40L) or anti-CD40 mAb in vitro. CD40 expression was readily detected in a large proportion of the cell lines and was augmented but not induced de novo by treatment with IFNgamma. Treatment of CD40-positive cell lines with rhCD40L or anti-CD40mAb enhanced cell surface expression of ICAM-1 and FAS and stimulated the production of IL-6, IL-8, GROalpha, GM-CSF and TNFalpha but not IL-4, IL-10, TGFbeta, MCP-1, RANTES, MIP-1beta, or IP-10. In addition, incubation of CD40+ tumour cell lines with immobilised rhCD40L or anti-CD40 mAb in vitro resulted in significant inhibition of proliferation and a corresponding decrease in viability. This CD40-mediated inhibition of cell growth was due, at least in part, to alterations in cell cycle and the induction of apoptosis. Transfection of CD40-negative tumour cell lines with the cDNA for CD40 conferred responsiveness to rhCD40L and anti-CD40 antibody. Finally, the presence of CD40 on the surface of carcinoma lines was found to be an important factor in the generation of tumour-specific T cell responses.

Mechanisms of Action of Intravesical Bacille Calmette-Guérin: Local Immune Mechanisms

The local immune response to mycobacteria is complex, but mycobacterial antigen presentation by phagocytes to T helper cells is the pivotal interaction. Bacille Calmette-Guérin (BCG) vaccination is associated with the development of antituberculosis immunity but not necessarily with antitumor immunity. Animal studies have shown that an intact host immune system is required for the antitumor activity of BCG. Immunosuppressed and, particularly, T cell-depleted individuals fail to respond to BCG immunotherapy. Clinical and laboratory evidence suggest that the antitumor activity is concentrated at the site of BCG administration, which reinforces the view that local immune mechanisms are responsible for this phenomenon.

Recent advances in bacillus Calmette-Guerin immunotherapy in bladder cancer.

The concept of using Mycobacterium for cancer treatment goes back to the 19th Century. Today, bacillus Calmette-Guerin (BCG) vaccine is a well-established treatment for human bladder cancer that is arguably superior to intravesical chemotherapy for superficial disease and is commonly used as the first-line adjuvant treatment. Much has been learnt about the effects of BCG on bladder cancer and the immune system, but deeper understanding is required in order to improve its efficacy further, to be able to reliably predict responders and ultimately to adapt this most successful form of cancer immunotherapy for the treatment of other malignancies. This article summarizes the current understanding of BCG cancer immunotherapy mechanisms and discusses possible future developments.

Interleukin-6 Production by Bladder Tumors is Upregulated by BCG Immunotherapy

PURPOSE To determine whether BCG therapy could upregulate interleukin-6 (IL-6) production in human transitional cell carcinomas (TCC). MATERIALS AND METHODS Immunohistochemistry of tumor biopsies and urinary cytospins and ELISA studies of urine from bladder cancer patients and TCC cell-line supernatants, before and after exposure to BCG, were performed. RESULTS Constitutive staining for IL-6 was found in the majority of bladder tumors. Interleukin-6 was detected in the urine of all 13 patients with carcinoma in situ and increased 5-fold during BCG therapy. Levels were variable but were greater in nonresponders (p < 0.01). During therapy both detached bladder urothelial cells and polymorphonuclear leukocytes stained for IL-6. Production of IL-6 increased in only 3 cell lines after exposure to BCG, but all 7 cell lines showed increases after exposure to interferon-gamma (p = 0.015). Grade 3 cell lines showed much greater upregulation than grade 1 and 2 cell lines. CONCLUSIONS The increase in IL-6 during BCG therapy may be caused by urothelial cells as well as leukocytes. The higher levels seen in nonresponders may be due to either higher grade or persisting tumor.

Induction of ICAM 1 expression on bladder tumours by BCG immunotherapy.

AIMS--To determine the expression of intercellular adhesion molecule 1 and 2 (ICAM 1 and 2) in transitional cell carcinoma cells before and after immunotherapy with Calmette-Guérin bacillus (BCG). METHODS--Frozen sections from 22 untreated bladder carcinomas were immunohistochemically examined with monoclonal antibodies to ICAM 1 and 2. Urinary cytospin slides were made for six patients for each of the six clinical instillations which constitute a therapeutic course. These slides were also stained for ICAM 1 and for leucocyte function associated antigen 1 (LFA 1). RESULTS--Bladder cancer cells did not essentially express either ICAM 1 or 2, but cells in the stromal areas surrounding tumour expressed both these antigens. After repeated instillations of BCG organisms ICAM 1 positive normal and neoplastic epithelial cells were observed in the urine. Cells obtained from the first three instillations expressed lower densities of ICAM 1 than those from the later instillations. Many neutrophils expressing LFA-1 and some lymphocytes were also noted in the cytospin slides and some of these were conjugated to tumour cells expressing ICAM 1. Six months after treatment a single maintenance dose of BCG induced ICAM 1 expression. CONCLUSION--Untreated superficial bladder carcinoma cells do not express ICAM 1 or 2, but these important immunological molecules were expressed in the stromal areas of tissue. Importantly, neoplastic cells in the urine expressed ICAM 1 after immunotherapy. This molecule can render bladder tumour cells vulnerable to non-antigen specific cytotoxicity mediated by activated lymphocytes.

Tumour immunology: false hopes—new horizons?

Abstract For the past 100 years, tumour immunology has witnessed peaks and troughs of interest. A recent meeting1The 5th Annual Congress of the British Society for Immunology was held at Brighton, UK, on 2–5 December 1997. 1 covered new technologies and recent developments in the field.

Autocrine regulation of ICAM-1 expression on bladder cancer cell lines: evidence for the role of IL-1α

We have studied the autocrine regulation of essential expression of the intercellular adhesion molecule-1 (ICAM-1) on 8 transitional cell carcinoma (TCC) cell lines (histopathological grades 1-3). The constitutive expression of ICAM-1 was regulated by soluble factors in an autocrine fashion. These factors were produced by all cell lines, with the exception of the MGH-U1 cell line. The effects observed could be largely attributed to IL-1 alpha. However, the residual ICAM-1 inducing activity (up to 30% of ICAM-1 induction) could not be associated with any known ICAM-1 inducers (IFN gamma, TNF alpha, TNF beta, IL-1 alpha, IL-1 beta, IL-4, retinoic acid, LPS). In contrast to recombinant derived cytokines, the IL-1 alpha present in tissue culture supernatant was only able to induce ICAM-1 on high-grade tumours and not low-grade cells. This discriminative effect is similar to that noted following in vitro culture of tumour cells with bacillus Calmette-Guerin organisms. Whether the production of soluble factors (e.g., IL-1 alpha) by TCC cell lines plays an essential autocrine role for bladder tumours and/or affects the interaction with cells of the immune system needs to be investigated further.

Cytokine modulation of epidermal growth factor receptor expression on bladder cancer cells is not a major contributor to the antitumour activity of cytokines

Epidermal growth factor is a potential mitogen for many different human tumours. Its effect is mediated via a bispecific receptor (EGFR), the expression of which correlates well with invasive disease. We investigated the modulation of EGFR by cytokines produced following bacillus Calmette Guerin (BCG)-immunotherapy. Our data demonstrate the IFN gamma, TNF alpha and IL-1 alpha can decrease the expression of EGFR on some bladder tumour cell lines. IFN gamma reduced EGFR expression on two of eight cell lines (RT4, SD). However, IL-1 and TNF did not share this activity. When cells were treated with a combination of all three cytokines, EGFR was decreased on three cell lines (RT4, RT112, SD) and furthermore, the change in the receptor expression was even more marked. Treatment with phorbol ester (thereby activating protein kinase C) resulted in rapid disappearance of the receptor from the cell surface. Interestingly, the decrease of EGFR expression did not require protein synthesis. Although the cytokines studied could down modulate EGFR, this only occurred on three out of eight cell lines; therefore, it is unlikely that the suppression of proliferative activity caused by cytokine-induced decrease of EGFR expression is central to the antitumour action of BCG therapy, but in a proportion of tumours this mechanism may be involved.