Immunotherapy in bladder cancer with keyhole-limpet hemocyanin: a randomized study

Protein-Based Adjuvants for Vaccines as Immunomodulators of the Innate and Adaptive Immune Response: Current Knowledge, Challenges, and Future Opportunities

New-generation vaccines, formulated with subunits or nucleic acids, are less immunogenic than classical vaccines formulated with live-attenuated or inactivated pathogens. This difference has led to an intensified search for additional potent vaccine adjuvants that meet safety and efficacy criteria and confer long-term protection. This review provides an overview of protein-based adjuvants (PBAs) obtained from different organisms, including bacteria, mollusks, plants, and humans. Notably, despite structural differences, all PBAs show significant immunostimulatory properties, eliciting B-cell- and T-cell-mediated immune responses to administered antigens, providing advantages over many currently adopted adjuvant approaches. Furthermore, PBAs are natural biocompatible and biodegradable substances that induce minimal reactogenicity and toxicity and interact with innate immune receptors, enhancing their endocytosis and modulating subsequent adaptive immune responses. We propose that PBAs can contribute to the development of vaccines against complex pathogens, including intracellular pathogens such as Mycobacterium tuberculosis, those with complex life cycles such as Plasmodium falciparum, those that induce host immune dysfunction such as HIV, those that target immunocompromised individuals such as fungi, those with a latent disease phase such as Herpes, those that are antigenically variable such as SARS-CoV-2 and those that undergo continuous evolution, to reduce the likelihood of outbreaks.

Litopenaeus vannamei hemocyanin exhibits antitumor activity in S180 mouse model in vivo

Hemocyanin is a multifunctional glycoprotein, which also plays multiple roles in immune defense. While it has been demonstrated that hemocyanin from some mollusks can induce potent immune response and is therefore undergoing clinical trials to be used in anti-tumor immunotherapy, little is currently known about how hemocyanin from arthropods affect tumors. In this study we investigated the anti-tumor activity of hemocyanin from Litopenaeus vannamei on Sarcoma-180 (S180) tumor-bearing mice model. Eight days treatment with 4mg/kg bodyweight of hemocyanin significantly inhibited the growth of S180 up to 49% as compared to untreated. Similarly, histopathology analysis showed a significant decrease in tumor cell number and density in the tissues of treated mice. Moreover, there was a significant increase in immune organs index, lymphocyte proliferation, NK cell cytotoxic activity and serum TNF-α level, suggesting that hemocyanin could improve the immunity of the S180 tumor-bearing mice. Additionally, there was a significant increase in superoxide dismutase (SOD) activity and a decrease in the level of malondialdehyde (MDA) in serum and liver, which further suggest that hemocyanin improved the anti-oxidant ability of the S180 tumor-bearing mice. Collectively, our data demonstrated that L. vannamei hemocyanin had a significant antitumor activity in mice.

Quality of transurethral resection of bladder tumor procedure influenced a phase III trial comparing the effect of KLH and mitomycin C

Background

Retrospective analysis of Center effect of the multi-center trial conducted to compare Immucothel (KLH Immunotherapy drug product) with Mytomycin-C (MM) concluded that efficacy evaluation of the drug product may be impacted by physician’s subjective performance of Transurethral resection of bladder tumor (TURBT).

Methods

A randomized trial was performed in 18 hospitals (clinical centers) and a total of 553 recruited, 283 patients under KLH arm and 270 patients under MM. An initial statistical analysis of efficacy comparisons between KLH and MM based on log-rank test performed for each center (hospital) showed 6 hospitals out of 18 hospitals a p-value of <0.05 and remaining 12 hospitals showed a p-values of >0.05. No association was observed between number of patients analysed and the associated p-values across hospitals. Final statistical analyses were carried out under each drug product using Kaplan-Meier survival analysis along with log-rank test after combining all eligible patients data for 6 hospital group and 12 hospital group.

Results

Median recurrence free survival (RFS) times (in weeks) showed statistical significance (p-value = 0.03) between two groups of hospitals under KLH arm, while similar median values showed no statistical significance (p-value = 0.05).

Conclusion

Center effect with respect to median RFS values under KLH was more pronounced than under MM. Under the presence of such center effect, for reasons other than product related effects, concluding superiority of one drug product over another may create confounding bias conclusions in multi-center clinical trials. In the above cited clinical trial study, physician’s prior experience on TURBT might have contributed to center effect in examining efficacies of KLH and MM. Similar observation was also noted in the literature on studies dealing with TURBT and in other clinical studies.

Trial registration

Data set used in this study is based on previously documented clinical trial in the literature: See (Lammers et al., J Clin Oncol 30:2273–9, 2012) and Acknowledgments.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-1843-5) contains supplementary material, which is available to authorized users.

Immune therapies in non-muscle invasive bladder cancer

OPINION STATEMENT

Non-muscle invasive bladder cancer (NMIBC) continues to be a challenging disease to manage. Treatment involves transurethral resection and, often, intravesical therapy. Appropriate patient selection, accurate staging, and morphological characterization are vital in risk-stratifying patients to those who would most benefit from receiving intravesical therapy. Bacillus of Calmette and Guérin (BCG) continues to be the first-line agent of choice for patients with intermediate- and high-risk NMIBC. Treatment should begin with the standard induction course of 6 weekly treatments. The inclusion of subsequent maintenance courses of BCG is imperative to optimal therapeutic response. While patients with intermediate-risk disease should receive 1 year of maintenance therapy, high-risk patients benefit from up to 3 years of maintenance therapy. BCG use should not be used in low-risk patients with de novo Ta, low-grade, solitary, <3-cm tumors. Conversely, patients with muscle-invasive disease should forgo intravesical immunotherapy and proceed directly to radical cystectomy. Cystectomy also should be considered in patients with multiple T1 tumors, T1 tumors located in difficult to resect locations, residual T1 on re-resection, and T1 with concomitant CIS. Although promising new immunotherapeutic agents, such as Urocidin, protein-based vaccines, and immune check point inhibitors are undergoing preclinical and clinical investigation, immunotherapy in bladder cancer remains largely reliant on intravesical BCG with surgical consolidation as the standard salvage treatment for patients with BCG failure.

Expert review: an update in current and developing intravesical therapies for non-muscle-invasive bladder cancer

Non-muscle-invasive bladder cancer is a highly prevalent disease and recurrences, after initial therapy, are common. Consequently, the healthcare costs for non-muscle-invasive bladder cancer are high. Despite a primary adequate response to adjuvant intravesical treatment, many patients suffer from recurrences, and some even from progression. To date, cystectomy remains the only option for those non-responding patients with high risk of recurrence and progression. Mainly because outcome after progression, in this group, is poor. Therefore, new intravesical therapies are needed. Moreover, new accurate and individual parameters, to distinguish responder from non-responders, will provide additional benefit in clinical decision-making. In this review, current diagnostics and therapies will be discussed. In addition, we will elucidate developing therapies in non-muscle-invasive bladder cancer.

Marine-sourced anti-cancer and cancer pain control agents in clinical and late preclinical development

The marine habitat has produced a significant number of very potent marine-derived agents that have the potential to inhibit the growth of human tumor cells in vitro and, in a number of cases, in both in vivo murine models and in humans. Although many agents have entered clinical trials in cancer, to date, only Cytarabine, Yondelis^® (ET743), Eribulin (a synthetic derivative based on the structure of halichondrin B), and the dolastatin 10 derivative, monomethylauristatin E (MMAE or vedotin) as a warhead, have been approved for use in humans (Adcetris^®). In this review, we show the compounds derived from marine sources that are currently in clinical trials against cancer. We have included brief discussions of the approved agents, where they are in trials to extend their initial approved activity (a common practice once an agent is approved), and have also included an extensive discussion of the use of auristatin derivatives as warheads, plus an area that has rarely been covered, the use of marine-derived agents to ameliorate the pain from cancers in humans, and to act as an adjuvant in immunological therapies.

Positions of the glycans in molluscan hemocyanin, determined by fluorescence spectroscopy

Molluscan hemocyanins are glycoproteins with different quaternary and carbohydrate structures. It was suggested that the carbohydrate chains of some Hcs are involved in their antiviral and antitumor effect, as well in the organization of the quaternary structure of the molecules. Using a well-known complex for saccharide sensing, positions and access to the carbohydrate chains in the native hemocyanins from Rapana venosa (RvH) and Helix lucorum (HlH) and also their structural subunits (RvH1, RvH2 and βcHlH) and functional units (FUs) were analysed by fluorescence spectroscopy and circular dichroism. Almost no effect was observed in the fluorescence emission after titration of the complex with native RvH and HlH due to lack of free hydroxyl groups which are buried in the didecameric form of the molecules. Titration with the structural subunits βcHlH and RvH2, increasing of the emission indicates the presence of free hydroxyl groups compared to the native molecules. Complex titration with the structural subunit βc-HlH of H. lucorum Hcs leads to a 2.5 fold increase in fluorescence intensity. However, the highest emission was measured after titration of the complex with FU βcHlH-g. The result was explained by the structural model of βcHlH-g showing the putative position of the glycans on the surface of the molecule. The results of the fluorescent measurements are in good correlation with those of the circular dichroism data, applied to analyse the effect of titration on the secondary structure of the native molecules and functional units. The results also support our previously made suggestion that the N-linked oligosaccharide trees are involved in the quaternary organization of molluscan Hcs.

Intracutaneous and intravesical immunotherapy with keyhole limpet hemocyanin compared with intravesical mitomycin in patients with non-muscle-invasive bladder cancer: results from a prospective randomized phase III trial

PURPOSE

Despite current treatment after transurethral resection of a bladder tumor, recurrences and progression remain a problem. Keyhole limpet hemocyanin (KLH) was beneficial in earlier studies. In this study, safety and efficacy of KLH were compared with that of mitomycin (MM).

PATIENTS AND METHODS

Patients with intermediate- and high-risk non-muscle-invasive bladder cancer (NMIBC) without carcinoma in situ were enrolled in a randomized phase III trial. In all, 283 patients were randomly assigned for 16 adjuvant intravesical instillations with KLH after preimmunization, and 270 patients were randomly assigned for 11 adjuvant intravesical instillations with MM. Primary outcome measurement was recurrence-free survival (RFS). Secondary outcome measurements were progression-free survival, adverse events (AEs), and the effect of delayed-type hypersensitivity (DTH) response on clinical outcome.

RESULTS

There were significantly more pT1 tumors in the MM group (P = .01). In a log-rank test, univariate and multivariate Cox regression analysis, KLH was less effective than MM regarding RFS (all P < .001). Progression was uncommon (n = 20). In univariate Cox regression analyses, KLH tended to prevent progression more effectively than MM, but in multivariate Cox regression analyses, this could not be shown. AEs were common but mild. Fever, flu-like symptoms, and fatigue occurred significantly more after KLH treatment. Allergic reactions and other skin disorders occurred significantly more after MM treatment. Significantly more DTH-positive patients developed a recurrence than DTH-negative patients.

CONCLUSION

KLH had a different safety profile and was inferior to MM in preventing NMIBC recurrences. KLH tended to be more effective than MM in preventing progression. More research is needed to clarify the immunologic effects of KLH and the effects of KLH on progression.

Evolution of intravesical immunotherapy for bladder cancer: mycobacterial cell wall preparation as a promising agent

BACKGROUND

The intra-cavitary administration of antineoplastic agents for the treatment of non-invasive bladder cancer has met with variable results. Mytomicin-C [corrected] is effective in the prevention of tumor recurrence when administered in the immediate post-resection period, but also exhibits activity against papillary tumors. It lacks efficacy in carcinoma in-situ (CIS) of the bladder. Bacillus Calmette-Guérin (BCG) has been shown to be effective against papillary tumors, but particularly in the treatment of CIS. Unfortunately, live BCG has serious safety limitations.

OBJECTIVE

To review the current situation with the use of non-viable preparations of mycobacteria (M. phlei) that have been investigated for the treatment of superficial bladder cancer in limited open-label clinical trials.

CONCLUSION

MCC (Urocidin) [corrected] has shown activity against a variety of tumor cells, both in vitro and in animal cancer models. Limited clinical trials have also shown it to be active against non-muscle invasive bladder tumors in patients who have previously failed one or more courses of chemotherapy and/or immunotherapy with BCG. An unique dual immunomodulatory and apoptotic mechanism of action has been proposed for MCC.

Keyhole limpet hemocyanin potentiates standard immunotherapy for melanoma

INTRODUCTION

Our hypothesis was that keyhole limpet hemocyanin (KLH) would augment the effects of standard immunotherapies for melanoma including interferon-alpha (AIFN) and interleukin (IL)-2.

METHODS

The HTB68 melanoma cell line was treated with KLH, AIFN, and IL-2 as single and combined agents. Cell viability, apoptotic activity, and vascular endothelial growth factor levels were all evaluated.

RESULTS

Cell growth was reduced with KLH (28%), AIFN (54%), and IL-2 (29%) (all P < .001). KLH and IL-2 combined exhibited a 47% inhibition of cell growth, whereas KLH and AIFN combined yielded a 67% reduction in cell growth (both P < .001). KLH and AIFN combined significantly increased both early (10%) and late (14%) apoptotic activity compared with controls (5% and 7%, P < .001).

CONCLUSIONS

The additive effects exhibited by the combination of KLH with AIFN or IL-2 are encouraging and support combination therapy as an effective treatment for this aggressive disease.

Immunotherapeutic effect of Concholepas hemocyanin in the murine bladder cancer model: evidence for conserved antitumor properties among hemocyanins

PURPOSE

We determined the antitumor properties of a newly available hemocyanin obtained from the Chilean gastropod Concholepas concholepas (Biosonda Corp., Santiago, Chile) in a syngeneic heterotopic mouse bladder carcinoma model. Since keyhole limpet hemocyanin (Pierce, Rockford, Illinois) is used increasingly in biomedicine as a carrier for vaccines and an immunotherapeutic agent for bladder transitional cell carcinoma, there is a growing interest in finding new substances that share its potent immunomodulatory properties. Considering that keyhole limpet hemocyanin and Concholepas concholepas hemocyanin differ significantly, it was not possible to predict a priori the antitumor properties of Concholepas concholepas hemocyanin.

MATERIALS AND METHODS

C3H/He mice were primed with Concholepas concholepas hemocyanin before subcutaneous implantation of mouse bladder tumor-2 cells. Treatment consisted of a subcutaneous dose of Concholepas concholepas hemocyanin (1 mg or 100 mug) at different intervals after implantation. Keyhole limpet hemocyanin and phosphate buffered saline served as positive and negative controls, respectively. In addition, experiments were designed to determine which elements of the immune response were involved in its adjuvant immunostimulatory effect.

RESULTS

Mice treated with Concholepas concholepas hemocyanin showed a significant antitumor effect, as demonstrated by decreased tumor growth and incidence, prolonged survival and lack of toxic effects. These effects were similar to those achieved with keyhole limpet hemocyanin. We found that each hemocyanin increased natural killer cell activity but the effect of Concholepas concholepas hemocyanin was stronger. Analysis of serum from treated mice showed an increased interferon-gamma and low interleukin-4, which correlated with antibody isotypes, confirming that hemocyanins induce a T helper type 1 cytokine profile.

CONCLUSIONS

To our knowledge our results are the first demonstration of the antitumor effect of a hemocyanin other than keyhole limpet hemocyanin. They suggest that this is an ancient conserved immunogenic mechanism shared by those hemocyanins that is able to enhance T helper type 1 immunity and lead to antitumor activity. Therefore, Concholepas concholepas hemocyanin may be an alternative candidate for providing safe and effective immunotherapy for human superficial bladder cancer.

Inhibition of melanoma growth by hemocyanin occurs via early apoptotic pathways

BACKGROUND

We hypothesized that keyhole limpet hemocyanin (KLH) would reduce cellular proliferation and effect apoptosis of melanoma cell lines in vitro.

METHODS

Two human melanoma cell lines (HTB68 and HTB72) were subjected to a dose-response treatment regimen of KLH (0.4 microg to 100 microg/well). Cell viability was tested by MTT assay (SIGMA, St Louis, MO) at 72 hours. Apoptosis and necrosis were measured by the Annexin V FITC assay (Biovision Inc, Mountain View, CA).

RESULTS

Melanoma cell proliferation was significantly reduced in the HTB68 cell line treated with 6.3 microg or higher doses of KLH. A significant reduction in cell growth was also observed in the HTB72 cells at 50 and 100 microg of KLH. KLH increased early apoptotic activity, whereas both late apoptosis and necrosis were decreased by the addition of KLH.

CONCLUSIONS

KLH significantly reduces cellular proliferation in vitro in melanoma, via early apoptotic pathways. The results warrant in vivo studies into the effects of KLH in melanoma.

In vitro effects of keyhole limpet hemocyanin in breast and pancreatic cancer in regards to cell growth, cytokine production, and apoptosis

BACKGROUND

We have previously shown the inhibitory effects of keyhole limpet hemocyanin (KLH) against breast and pancreatic cancer in vitro. We hypothesize that its actions in breast and pancreas cancer cells are via apoptotic or cytokine pathways.

METHODS

Two breast cancer cell lines, ZR75-1 and MCF-7, and one pancreas cancer cell line, PANC-1, were treated with KLH at 500 mug, 250 mug, and 250 ng/mL. Cell viability, cytokine production, and apoptosis were measured.

RESULTS

Significant growth inhibition was observed in all cell lines at all KLH concentrations tested. Significant changes in cytokine production were observed in all cell lines. An increase in early and late apoptotic activity was observed in the MCF-7, whereas a reduction in late apoptotic activity was observed in the ZR75-1 cells.

CONCLUSIONS

KLH directly inhibits the growth of human breast and pancreas cancer in vitro by apoptotic and nonapoptotic mechanisms.

Superficial Bladder Cancer Therapy: A Review

Most bladder cancers present as a superficial disease, confined to the bladder mucosa or submucosal layer, without muscle invasion. Most superficial tumors have a propensity for recurrence after transurethral resection; some have a high risk for progression to muscle invasion. The treatment aim in superficial bladder cancer with intravesical therapy is three-fold: (1) eradicate existing disease, (2) prevention of recurrence, (3) prevention of tumor progression. The prognostic factors (tumor stage, grade, size, number and recurrence pattern) allow the stratification of tumors in different risk groups to plan treatment. Studies on pharmacokinetics have proved the efficacy of optimized drug delivery. Comparing resection with and without intravesical chemotherapy, a short-term reduction, approximately 15%, in tumor recurrence with chemotherapy can be obtained, but no effect on progression was proven. No agent has proved to be more effective than the others. A single instillation of chemotherapy immediately after transurethral resection has proven to be effective, but the role of maintenance therapy is controversial. Immunotherapy, in the form of Bacillus Calmette-Guerin, is generally shown to be more effective than chemotherapy, even if the results in comparison to mitomycin C do not result conclusive. Several new approaches are being explored to improve the efficacy of this therapy.

Direct electron transfer between copper-containing proteins and electrodes

The electrochemistry of some copper-containing proteins and enzymes, viz. azurin, galactose oxidase, tyrosinase (catechol oxidase), and the "blue" multicopper oxidases (ascorbate oxidase, bilirubin oxidase, ceruloplasmin, laccase) is reviewed and discussed in conjunction with their basic biochemical and structural characteristics. It is shown that long-range electron transfer between these enzymes and electrodes can be established, and the mechanistic schemes of the DET processes are proposed.

Evaluation of two carrier protein-angiotensin I conjugate vaccines to assess their future potential to control high blood pressure (hypertension) in man

AIMS

We aim to modulate the renin-angiotensin system (RAS) by active immunization against angiotensin I hormone (AI), potentially providing a novel conjugate vaccine treatment for hypertension in man.

METHODS

Immunization studies in rat and human subjects compare the effectiveness of tetanus toxoid (TT) and keyhole limpet haemocyanin (KLH) vaccines for immunotherapy following conjugation with an AI peptide analogue (AI). Cardiovascular responses were assessed in immunized rats and human subjects (two-dose trial only), following increasing i.v. infusions of either AI or angiotensin II hormone (AII).

RESULTS

The AI-TT and AI-KLH conjugate vaccines induced an equivalent immune response, and inhibition of the pressor effects to exogenous AI in rats. Single-dose clinical trials with both conjugate vaccines only resulted in an immune response to the KLH carrier protein. A two-dose clinical trial of AI-KLH conjugate vaccine resulted in a significant immune response to AI. A shift in diastolic blood pressure (DBP) dose-response was demonstrated following challenge with AI and AII for the study volunteer showing the largest anti-AI IgG induction.

CONCLUSION

KLH was shown to be a suitable alternative to TT as a carrier protein for AI, thus supporting continued evaluation of our AI-KLH conjugate vaccine for treatment of hypertension in man.

In vitro anticancer effects of a novel immunostimulant: keyhole limpet hemocyanin

BACKGROUND

Keyhole limpet hemocyanin (KLH) is a recently described immune stimulant and hapten carrier derived from a circulating glycoprotein of the marine mollusk Megathura crenulata. It has been reported to be a potent form of intravesical immunotherapy for the treatment of transitional cell carcinoma of the bladder and has been used in a variety of genitourinary tumors. We hypothesized that KLH would be effective against other cancer cells in vitro.

METHODS

Multiple cancer cell lines were tested, including estrogen-dependent breast (MCF-7), estrogen-independent breast (ZR75-1), pancreas (PANC-1, MIA-PaCa), and prostate (DU145). Serial twofold dilutions of KLH were prepared in sterile 96-well plates. Dose-response curves were performed beginning with a concentration of 100 microg of KLH/well and ending at a concentration of 0.8 ng/well. Cells were added at concentrations of 5 x 10(4) cells per well. Cell viability was evaluated at 24 and 72 h by MTT assay at an absorbance of 570 nm.

RESULTS

Significant (P < 0.05) cancer cell growth inhibition was observed in four of the five cell lines tested at both time treatment intervals. The breast cancer line ZR75-1 exhibited a mean growth inhibition of 43 +/- 1.1% (range 37 to 59%) at 72 h, whereas treated MCF-7 cells had an average of 39 +/- 9.1% growth inhibition (range 35 to 44%) at these same concentrations. Treated PANC-1 cells had a mean growth inhibition of 19 +/- 0.8% (range 4 to 46%) at 72 h. The DU145 prostate cancer cell line averaged a 6 +/- 1.3% growth inhibition (range -19 to 55%) over the concentrations tested.

CONCLUSIONS

The direct growth inhibition of multiple tumor cell-lines exhibited by KLH is significant and warrants further in vitro mechanistic studies and in vivo experiments. Investigation into the efficacy and mechanism of response could directly lead to more effective treatment regimens for patients suffering from these diseases.

Monoclonal antibodies to molluskan hemocyanin from Concholepas concholepas demonstrate common and specific epitopes among subunits

We studied the reactivity of mouse monoclonal antibodies (MAbs) against the hemocyanin from the Chilean marine gastropod Concholepas concholepas (CCH). This protein has been successfully used as a carrier to produce antibodies to haptens and peptides. All MAbs (13) belonging to IgG subclass exhibit dissociation constants (K(d)) from 1 x 10(-7) M to 1 x 10(-9) M. MAbs were characterized by enzyme-linked immunosorbant assay (ELISA) using CCH treated with different procedures, including dissociation into CCH-A and CCH-B subunits, Western blot, enzymatic digestion, chemical deglycosylation, and thermal denaturation. MAbs were classified into three categories, according to subunit specificity by ELISA. The epitope distribution shows that CCH subunits display common epitopes (group I, 5 MAbs, 1H5, 2A8, 3A5, 3B3, and 3E3), as well as specific epitopes for CCH-A subunits (group II, 3 MAbs, 1B8, 4D8, and 8E5) and for CCH-B subunits (group III, 5 MAbs, 1A4, 1E4, 2H10, 3B7, and 7B4). The results can be summarized as follows: (1). six antibodies react with thermal denatured CCH, suggesting that they recognize linear epitopes, whereas seven recognize conformational epitopes; (2). oxidation of carbohydrate moieties does not affect the binding of the MAbs; (3). enzymatic digestion of CCH decreases the reactivity of all antibodies irrespective of the protease used (elastase or trypsin); (4). bringing together the above data, in addition to epitopic complementarity analysis, we identified 12 different epitopes on the CCH molecule recognized by these MAbs. The anti-CCH MAbs presented here can be useful tools to understand the subunit organization of the CCH and its complex structure, which can explain its immunogenic and immunostimulating properties in mammals.

Diagnosis and management of superficial bladder cancer

Bladder cancer is the fourth leading cause of cancer in American men, accounting for more than 12,000 deaths annually. It was one of the first malignancies in which carcinogens were recognized as an important factor in its cause. Currently, cigarette smoking is by far the most common cause of bladder cancer, although occupational exposure to arylamines has been implicated in the past. Gross or microscopic hematuria is the most common sign at presentation. Initial radiologic evaluation usually includes the excretory urography (intravenous pyelography), although further evaluation of the renal parenchyma with ultrasound or computed tomography scanning has been advocated by some. These radiologic studies are unable to provide adequate bladder imaging, and thus cystoscopy is required for the diagnosis of bladder cancer. Most bladder cancers present as "superficial" disease, confined to the bladder mucosa or submucosal layer, without muscle invasion. Superficial tumors consist of papillary tumors that are mucosally confined (Ta), papillary or sessile tumors extending into the lamina propria (T1), and carcinoma in situ, which occurs as "flat" mucosal dysplasia, which can be focal, diffuse, or associated with a papillary or sessile tumor. The natural history of these pathologic subtypes differ significantly. Most superficial tumors (60% to 70%) have a propensity for recurrence after transurethral resection. Some (15% to 25%) are at high risk for progression to muscle invasion. Most superficial tumors can be stratified into high- or low-risk groups depending on tumor stage, grade, size, number, and recurrence pattern. It is important to identify those tumors at risk for recurrence or progression so that adjuvant intravesical therapies can be instituted. Many intravesical chemotherapeutic agents have been shown to reduce tumor recurrence when used in conjunction with transurethral tumor resection. Unfortunately, however, none of these agents have proved to be of benefit in preventing disease progression. Most are given intravesically on a weekly basis, although many studies suggest that a single instillation immediately after transurethral resection may be as good as a longer course of therapy. Although all of these drugs have toxicity, they usually are well tolerated. Intravesical bacille Calmette-Guérin (BCG) is an immunotherapeutic agent that when given intravesically is very effective in the treatment of superficial transitional cell carcinoma. Compared with controls, BCG has a 43% advantage in preventing tumor recurrence, a significantly better rate than the 16% to 21% advantage of intravesical chemotherapy. In addition, BCG is particularly effective in the treatment of carcinoma in situ, eradicating it in more than 80% of cases. In contrast to intravesical chemotherapy, BCG has also been shown to decrease the risk of tumor progression. The optimal course of BCG appears to be a 6-week course of weekly instillations, followed by a 3-week course at 3 months in those tumors that do not respond. In high-risk cancers, maintenance BCG administered for 3 weeks every 6 months may be optimal in limiting recurrence and preventing progression. Unfortunately, adverse effects associated with this prolonged therapy may limit its widespread applicability. In those patients at high risk in whom BCG therapy fails, intravesical interferon-alpha with or without BCG may be beneficial in some. Photodynamic therapy has also been used but is limited by its toxicity. In patients who progress or do not respond to intravesical therapies, cystectomy should be considered. With the development of orthotopic lower urinary tract reconstruction to the native urethra, the quality of life impact of radical cystectomy has been lessened.

Chemoprevention of superficial bladder cancer

The development, evaluation and approval of promising agents for bladder cancer prevention (chemoprevention)depends upon the rational integration of four key components: a) Agents (pharmaceuticals, biologics and nutrients); b) Biomakers (intermediate endpoints that predict for clinical response and risk reduction; c) Cohorts (well defined high risk target populations d) Designs (efficient trial designs linked to the clinical phase of development). The promise of this overall strategy is the ability to conduct faster, smaller and more cost effective trials which incorporate validated surrogate endpoints rather than conventional clinical endpoints (cancer incidence, recurrence and survival). Current National Cancer Institute (NCI) phase III bladder cancer chemopreventive trials in progress are described. Since most patients with superficial (transitional cell) bladder cancer present with early disease (Ta, T1, Tis lesions) that frequently recurs and is easily accessible by serial cystoscopy and urine cytology, bladder cancer serves as a powerful clinical for conducting prevention trials of new agents for a tobacco related malignancy.

Isolation and spectroscopic characterization of the structural subunits of keyhole limpet hemocyanin

Keyhole limpet hemocyanin is a respiratory glycoprotein of high molecular weight from the gastropod mollusc Megathura crenulata. Two subunits, KLH1 and KLH2, were isolated using ion exchange chromatography and their physical properties are compared with the parent molecule. The various proteins are characterized by fluorescence spectroscopy, combined with fluorescence quenching studies, using acrylamide, cesium chloride and potassium iodide as tryptophan quenchers. The conformational stability of the native aggregate and its isolated structural subunits are also studied by circular dichroism and fluorescence spectroscopy as a function of temperature, as well as in the presence of guanidinium hydrochloride and urea. The associated subunits in the hemocyanin aggregates increase considerably the melting temperature to 67 degrees C and the free energy of stabilization in water, DeltaG(H(2)O)(D), towards guanidinium hydrochloride is higher for the decamer as compared to the isolated subunits; this difference can be accounted for by the stabilizing effects of intra-subunit interactions exerted within the oligomer. The copper-dioxygen complex at the active site additionally stabilizes the molecule, and removing of the copper ions increases the tryptophan emission and the quantum yield of the fluorescence.

Immunotherapy for bladder cancer

The primary role of immunotherapy for bladder cancer is to treat superficial transitional cell carcinomas (ie, carcinoma in situ, Ta, and T1). Immunotherapy in the form of bacille Calmette-Guérin (BCG), interferon, bropirimine, keyhole limpet hemocyanin, and gene therapy is intended to treat existing or residual tumor, to prevent recurrence of tumor, to prevent progression of disease, and to prolong survival of patients. Presently, BCG is commonly used and is the most effective immunotherapeutic agent against superficial transitional cell carcinoma. Data support that BCG has a positive impact on tumor recurrence, disease progression, and survival. Proper attention to maintenance schedules, route of administration, dosing, strains, and viability is essential to obtain the maximum benefits of BCG immunotherapy. This review highlights and summarizes the recent advances concerning immunotherapy, with special emphasis on BCG therapy for transitional cell carcinoma.

Immunostimulation in the urinary bladder by local application of Nocardia rubra cell-wall skeletons (Rubratin) and bacillus Calmette-Guérin as therapy for superficial bladder cancer: a comparative study

Twelve patients with superficial bladder cancer were treated with intravesical instillations of Rubratin (ASTA Pharma AG, Frankfurt, Germany), a cell-wall preparation of Nocardia rubra. The objective was to compare the immunostimulating effect of Rubratin with that of bacillus Calmette-Guérin (BCG). Local immunostimulation was determined by cytokine induction in serially collected urine samples during the first 24 h after each instillation, leukocyte influx into the urine, and phenotypic analysis of the lymphocyte fraction. Levels of Rubratin-induced interleukin (IL)-1 beta, IL-6, and tumor necrosis factor-alpha were significantly elevated compared with pretherapy levels. Rubratin induced leukocyte influx into the urine. T-cell activation (IL-2 receptor and human leukocyte antigen-DR expression) can be induced, and CD4:CD8 cell ratios can be increased. All parameters indicated that Rubratin-induced immunostimulation was less than that associated with BCG. In conclusion, although local Rubratin-induced immunostimulation occurs in a limited number of patients, the amount of immunocompetent cells attracted to the bladder seems to be less than that associated with BCG therapy, thus resulting in lower levels of cytokine production (which may reflect less clinical efficacy).

Current concepts in assessment and treatment of bladder cancer

Transitional cell carcinoma of the bladder is comprised of a variety of cancer diatheses that manifest a spectrum of distinct biologic potentials. The challenge is to control superficial disease recurrence and progression and to identify invasive carcinoma at an earlier stage, when it may be more amenable to cure.

Interferons and bladder cancer

With the introduction of BCG, intravesical instillation of immunotherapeutic agents has become a mainstay of therapy in the treatment of superficial bladder cancer. Interferon is capable of inducing a non-specific cellular and humoral immune response towards tumor cells. It has shown promise in reducing the recurrence and progression rates of superficial bladder cancer. In contrast to BCG, intravesical interferon is associated with minimal side effects and a very low dropout rate. Current research has focused on the use of interferon in combination with immunotherapeutic and cytotoxic drugs.

Keyhole limpet hemocyanin (KLH): a biomedical review

In this review we present a broad survey of fundamental scientific and medically applied studies on keyhole limpet hemocyanin (KLH). Commencing with the biochemistry of KLH, information on the biosynthesis and biological role of this copper-containing respiratory protein in the marine gastropod Megathura crenulata is provided. The established methods for the purification of the two isoforms of KLH (KLH1 and KLH2) are then covered, followed by detailed accounts of the molecular mass determination, functional unit (FU) structure, carbohydrate content, immunological analysis and recent aspects of the molecular genetics of KLH. The transmission electron microscope (TEM) has contributed significantly to the understanding of KLH structure, primarily from negatively stained images. We give a brief account of TEM studies on the native KLH oligomers, the experimental manipulation of the oligomeric states, together with immunolabelling data and studies on subunit reassociation. The field of cellular immunology has provided much relevant biomedical information on KLH and has led to the expansion of use of KLH in experimental immunology and clinically as an immunotherapeutic agent; this area is presented in some detail. The major clinical use of KLH is specifically for the treatment of bladder carcinoma, with efficacy probably due to a cross-reacting carbohydrate epitope. KLH also has considerable possibilities for the treatment of other carcinomas, in particular the epithelially derived adenocarciomas, when used as a carrier for carcinoma ganglioside and mucin-like epitopes. The widespread use of KLH as a hapten carrier and generalised vaccine component represent other major on-going aspects of KLH research, together with its use for the diagnosis of Schistosomiasis, drug assay and the treatment of drug addiction. Immune competence testing, assessment of stress and the understanding of inflammatory conditions are other areas where KLH is also making a useful contribution to medical research.

Primary structure and unusual carbohydrate moiety of functional unit 2-c of keyhole limpet hemocyanin (KLH)

The complete amino acid sequence of the Megathura crenulata hemocyanin functional unit KLH2-c was determined by direct sequencing and matrix-assisted laser desorption ionization mass spectrometry of the protein, and of peptides obtained by cleavage with EndoLysC proteinase, chymotrypsin and cyanogen bromide. This is the first complete primary structure of a functional unit c from a gastropod hemocyanin. KLH2-c consists of 420 amino acid residues. Circular dichroism spectra indicated approx. 31% beta-sheet and 29% alpha-helix contents. A multiple sequence alignment with other molluscan hemocyanin functional units revealed average identities between 41 and 49%, but 55% in case of Octopus hemocyanin functional unit c which is the structural equivalent to KLH2-c. KLH2-c has a molecular mass of approx. 48 kDa as calculated from its sequence and a measured mass of approx. 56 kDa; the mass difference is attributed to the sugar side chains usually decorating molluscan hemocyanin. However, inspection of the sequence of KLH2-c revealed no potential N-linked carbohydrate attachment sites, and this was supported by its inability to bind concanavalin A. Also KLH1-c was unreactive, whereas most, if not all, other functional units of KLH1 and KLH2 reacted positively to this lectin. On the other hand, peanut agglutinin specifically binds KLH2-c, indicating the presence of O-glycosidically linked carbohydrates in this functional unit. This contrasts to all other KLH functional units (including KLH1-c), which lack O-linked glycosides. The present results are discussed in view of the recent X-ray structure of the functional unit g from Octopus hemocyanin, and a published record of the Thomsen Friedenreich tumor antigenic epitope in KLH.

Mass determination, subunit organization and control of oligomerization states of keyhole limpet hemocyanin (KLH)

Analytical dark-field scanning transmission electron microscopy (STEM) of freeze-dried unstained specimens of keyhole limpet hemocyanin (KLH; from Megathura crenulata, a prosobranch gastropod) gave a molecular mass of 400 kDa for the subunit of KLH1 and of 345 kDa for the subunit of KLH2, which confirms our published values from SDS/PAGE. Within the 400-kDa KLH1 subunit we identified, by limited proteolysis, isolation of fragments and N-terminal sequencing, eight distinct 45-60 kDa functional domains (termed 1a through 1h) and determined their sequential arrangement. The KLH1 domains differ biochemically and immunologically from each other and from the previously characterized seven domains of KLH2 (termed 2a through 2g). Our partial amino acid sequences suggest that a domain, equivalent to the C-terminal domain 1h, is missing in KLH2. This deficiency is believed to be genuine and not an artifact of the subunit preparation procedure, since STEM measurements of the native didecamers yielded a mass difference of about 800 kDa between KLH1 and KLH2 (8.3 MDa versus 7.5 MDa), correlating with 20 copies of a functional 1h domain. It was also shown that the KLH1 didecamer can be rapidly split (minutes) into an almost homogeneous population of stable decamers by increasing the pH of the Tris/saline stabilizing buffer (routinely pH 7.4), which contains 5 mM CaCl2 and 5 mM MgCl2, to pH 8.5. Reformation of the didecamers occurred more slowly (days) upon dialysis against the pH 7.4 stabilizing buffer. Addition of 100 mM calcium and 100 mM magnesium ions to the pH 7.4 stabilizing buffer leads to the more rapid (overnight) formation of didecamers together with a significant number of previously unobserved KLH1 multidecamers, which could be structurally distinguished from the established multidecamers of KLH2.

Immunotherapy of bladder cancer

Intravesical therapy has been used in the management of superficial transitional cell carcinoma (TCC) of the urinary bladder (i.e., Ta, Tl, and carcinoma in situ) with specific objectives which include treating existing/residual tumor, preventing recurrence of tumor, preventing disease progression, and prolonging survival. The initial clinical stage and grade remain the main determinant factors in survival irrespective of the treatment. Presently, bacillus Calmette-Guerin (BCG) immunotherapy remains the most effective treatment and prophylaxis for TCC (Ta, Tl, CIS) and has positive outcomes on tumor recurrence rate, disease progression, and prolongation of survival. Prostatic urethral mucosal involvement with bladder cancer can be effectively treated with BCG intravesical immunotherapy-it has demonstrated a reduction in tumor recurrence rates, but has had no positive impact on disease progression or prolongation of survival. Interferons, keyhole-limpet hemocyanin (KLH), bropirimine, and PHOTOFRIN-photodynamic therapy (PDT) are under investigation in the management of TCC and early results are encouraging. This comprehensive review highlights recent developments in intravesical therapy of bladder cancer and summarizes the mechanisms of action of BCG, and the important role of intravesical BCG immunotherapy and other immunotherapeutic agents in the therapy and prophylaxis of superficial TCC of the urinary bladder.

Biologic response modifiers in the management of superficial bladder cancer

For the treatment of existing transitional-cell carcinoma or for prophylaxis of recurrent disease, intravesical therapy should be chosen according to stage. Papillary disease (stages Ta, Tl) may be treated effectively either with an alkylating agent or with bacillus Calmette-Guérin (BCG). BCG is the agent of choice for the treatment of Hat carcinoma in situ (Tis), with the recommended treatment course comprising 12 weekly and 12 monthly instillations. Intravesical interferon and many of the other biologic response modifiers mentioned herein may be effective for patients with Ta disease who have failed BCG therapy.

Prophylactic intracavitary treatment with interferon alpha increases interferon gamma production by peripheral blood mononuclear cells in patients with superficial transitional cell carcinoma of the bladder

The immunomodulatory effect of prophylactic intravesical instillations of interferon alpha 2b (IFN-alpha-2b) on interferon gamma (IFN-gamma) and interleukin 4 (IL-4) production by peripheral blood mononuclear cells (PBMCs) from patients with superficial transitional cell carcinoma (STCC) of the bladder has been analysed. There were no significant differences in the production of IFN-gamma and IL-4 by PBMCs from untreated patients and healthy control subjects after 24 h of phytohaemagglutinin (PHA) stimulation. However, between 3 and 6 months after finishing the prophylactic intracavitary treatment with IFN-alpha-2b, PHA-stimulated PBMCs from patients with STCC of the bladder showed a significantly enhanced production of IFN-gamma and a significantly decreased production of IL-4. Both IFN-gamma and IL-4 returned to pretreatment levels 1 year after ending the treatment. In conclusion, prophylactic intravesical instillations of IFN-alpha-2b in patients with STCC of the bladder have an immunoregulatory effect on the production of IFN-gamma and IL-4 by PBMCs.

Rapana thomasiana grosse (gastropoda) haemocyanin: spectroscopic studies of the structure in solution and the conformational stability of the native protein and its structural subunits

1. The stability towards pH changes, thermal and chemical (guanidine hydrochloride) denaturation of the oxy- and apo-forms of the native Rapana thomasiana haemocyanin and its structural subunits, RHSS1 and RHSS2, has been investigated using fluorescence and CD spectroscopy. The association of the subunits into haemocyanin aggregates increases considerably the melting temperature and the free energy of stabilization in water. The guanidine hydrochloride denaturation of the aggregated oxygen-transporting protein depends slightly on the protein concentration. The denaturation of the individual subunits is concentration-independent. Rapana haemocyanin is 5.9-7.5 kJ/mol more stable than the constituent polypeptide chains. 2. Upon excitation of the native haemocyanin and the subunits at 295 or 280 nm the fluorescence emission is determined by tryptophyl residues 'buried' deeply in the hydrophobic interior of the protein globules. This is confirmed by quenching experiments with acrylamide, caesium and iodide ions. The efficiency of the radiationless energy transfer between the phenol (donor) and indole (acceptor) fluorophores in the three species, native haemocyanin, RHSS1 and RHSS2, has been determined. An efficient 'interchain' energy transfer between tyrosyl and tryptophyl residues from different polypeptide chains occurs in the non-dissociated form of the haemocyanin. 3. The tryptophan emission of the oxyhaemocyanin, oxy-RHSS1 and oxy-RHSS 2 is strongly quenched by the copper-dioxygen complex at the active site and the respective quantum yields of fluorescence of the oxygenated species are 4-7 times lower than those of the apo-forms. Protonated imidazole groups quench the fluorescence of neighbouring exited indole rings, probably by charge-transfer complex formation.

Keyhole limpet hemocyanin: structural and functional characterization of two different subunits and multimers

Keyhole limpet hemocyanin (KLH), the large respiratory glycoprotein from the primitive gastropod mollusc, Megathura crenulata, is a potent immunogen used classically as a carrier protein for haptens and more recently in human vaccines and for immunotherapy of bladder cancer. Two KLH isoforms were identified and isolated by high-performance anion exchange chromatography. Subsequent analyses disclosed that these isoforms--designated KLH-A and KLH-B--were composed of distinct subunits that differed in primary structure, molecular weight (KLH-A was 449,000 and KLH-B was 392,000), polymerization/reassociation characteristics, and O2-binding constants (KLH-A had a P50 of 7.32 and KLH-B had a P50 of 2.46). Both subunits appear to be composed of eight oxygen binding domains, and reassociate in solution only with like subunits. These results support the concept that structural and functional heterogeneity is a common feature of molluscan hemocyanins, and provide a rational basis for studying and optimizing the immunostimulatory properties of KLH.

Functional unit of the Rapana thomasiana (Grosse) (marine snail, gastropod) hemocyanin

The amino terminal functional unit (domain a) of the Rapana hemocyanin "heavy" structural subunit, designated as Rta, was obtained after limited trypsinolysis of the whole polypeptide chain. Mass spectrometric analysis showed a molecular mass of 49,698 daltons for the electrophoretically homogeneous fragment. Twenty-five amino acid residues were sequenced directly from the N-terminus of Rta, which allowed the location of the domain in the polypeptide chain of the subunit. Physicochemical parameters were determined by absorption and fluorescence spectroscopy and circular dichroism. Comparison with the respective parameters of the whole Rapana hemocyanin showed that the polypeptide backbone folding, binuclear active site and capability of oxygen binding of the isolated functional unit are identical to those of the native hemocyanin. Comparison of N-terminal sequences of functional units from different molluskan hemocyanins and located at different positions revealed some evolutionary relationships.

Immunohistological findings in patients with superficial bladder carcinoma after intravesical instillation of keyhole limpet haemocyanin

OBJECTIVE

To determine whether keyhole limpet haemocyanin (KLH) instilled intravesically improves the local cellular response within the bladder wall of patients suffering from superficial bladder carcinoma.

PATIENTS AND METHODS

Twelve patients (10 men and two women, mean age 67 years, range 42-85) with superficial carcinomas of the bladder were treated for 6 consecutive weeks and then monthly for 1 year with 20 mg KLH in 20 mL saline instilled intravesically after complete resection of the tumours. Biopsies were taken for immunohistochemical examination before treatment and again 6 weeks, 3, 6 and 9 months after treatment. Six patients with no evidence of cystitis or malignant bladder disease acted as a control group. Immunofluorescent staining of the biopsies was performed using monoclonal antibodies to the T-cell markers CD4 and CD8, and to CD14 (monocytes), CDw15 (granulocytes), CD19 B-cells (Pan-B), CD68 (macrophages) and HLA-DR. Anti-KLH antibody-producing plasma cells were detected using a standard technique. A semiquantitative analysis of locally infiltrating cell types was performed.

RESULTS

After treatment with KLH the increase of CD8+ suppressor cells was less pronounced than that of CD4+ helper cells. The T-helper/inducer to T-suppressor/cytotoxic cell ratio thus altered from 0.8:2.0 before treatment to 1.6:2.3 afterwards. Hence, the number of T-helper cells had increased considerably, whereas there was only a moderate increase in the number of T-suppressor cells. This cellular ratio could be detected for 9 months after KLH therapy. The numbers of activated HLA-DR+ immune cells in the submucosa and among urothelial cells also increased after KLH instillation. The degree of mononuclear cell infiltration of the submucosa increased considerably, but granulocyte infiltration was only moderate. Lymph follicles with enhanced B-lymphocyte counts were also detected.

CONCLUSION

Immune-cell infiltration into the urothelium and enhanced activation (expression of class II antigens) suggests distinct processes of cellular antigen recognition, which could be detected for up to 9 months after the beginning of KLH therapy. This may represent a basic functional mechanism of KLH therapy.

Efficacy of local Bacillus Calmette-Guérin treatment in superficial bladder cancer relapsing under Keyhole-Limpet Hemocyanin immunotherapy

The efficacy of local immunotherapy with Keyhole-Limpet Hemocyanin (KLH) and Bacillus Calmette-Guérin (BCG) in preventing recurrence of superficial bladder cancer (stages pTa to pT1; grades 1 to 3) was checked in 96 patients. All tumours were resected and all patients were presumed to be free of malignant disease at initiation of prophylactic KLH instillations. Before starting KLH instillations (20 mg/administration week for 6 weeks, followed by regular (bi)monthly instillations for 3 years altogether) all patients were intracutaneously immunized with 1 mg KLH. Tumour relapse under this therapeutic schedule was the indication for BCG instillations (120 mg BCG-Connaught; administration in analogy to KLH treatment). This study has proved that (1) prophylactic KLH treatment reduced superficial bladder cancer relapse rate after surgical intervention without considerable local/systemic side effects and (2) local BCG-administration was therapeutically effective in relapsing/progressive disease under KLH treatment. There were, however, pronounced side effects.

Use of intracavitary interferon-alpha-2b in the prophylactic treatment of patients with superficial bladder cancer

BACKGROUND

The evolution of superficial transitional cell carcinoma (TCC) of the bladder poses a clinical management problem due to its tendency to recur after initial transurethral resection (TUR). Natural Killer (NK) cells are a distinct subset of lymphocytes that possess the ability to lyse tumor cells without prior sensitization in a nonmajor histocompatibility-restricted fashion. These cytotoxic cells constitute a relevant barrier against the local growth and systemic dissemination of neoplastic diseases.

METHODS

The immunomodulatory effect, after TUR of the tumor, of the prophylactic treatment with intravesical instillations of interferon-alpha-2b (IFN-alpha-2b) upon the NK activity of peripheral blood mononuclear cells (PBMNC) in 17 patients with superficial TCC of the bladder was analyzed using a 4-hour 51sodium chromate (51Cr)-release cytotoxicity assay against both NK-sensitive, or K562, and NK-resistant, or JY, tumor target cells.

RESULTS

There were no significant modifications of the NK activity of PBMNC during the 3 months of IFN-alpha-2b intracavitary treatment (P > 0.05). However, with respect to their levels before treatment, NK activity in PBMNC at 3 months posttreatment was enhanced significantly in the 14 patients who showed no sign of tumor recurrence in the 12 months of follow-up (P < 0.01). Six months after finishing the intracavitary IFN-alpha-2b instillations, the PBMNC NK activity in these patients had returned to the levels found before initiating the therapy (P > 0.05). This temporary enhancement of the PBMNC NK activity was not found in three patients with evidence of tumor recurrence at some time during the 12 months after treatment. In similar experimental conditions, significant enhancement of the NK activity in PBMNC was not observed in nine patients with superficial bladder TCC who were treated with intracavitary instillations of mitomycin C (MMC) after the TUR of the tumor and who were free of recurrence of the disease at 1 year of follow up.

CONCLUSION

The prophylactic intracavitary treatment of superficial bladder TCC with IFN-alpha-2b may induce an immunomodulatory effect in the NK activity of PBMNC that appears to be associated with the clinical evolution of the disease.