A novel immunotherapy for superficial bladder cancer by intravesical immobilization of GM-CSF

The Management of Bacillus Calmette-Guérin (BCG) Failure in High-Risk Non-muscle Invasive Bladder Cancer: A Review Article

Non-muscle invasive bladder cancer (NMIBC) is a common urological malignancy, and bacillus Calmette-Guérin (BCG) therapy is the gold standard treatment in intermediate and high-risk groups. However, BCG failure occurs in a significant proportion of patients, emphasizing the need for effective alternative treatment modalities to address this burden. These treatments include immunotherapy, enhanced drug delivery, targeted therapy, device-assisted chemotherapy, vaccine therapy, and gene therapy, which show varying degrees of safety and efficacy. The objective of this review is to summarize the current evidence and ongoing research on these emerging therapies, offering insight into their potential for improving patient outcomes and quality of life. Although radical cystectomy remains the standard of care for high-risk NMIBC patients unresponsive to BCG, novel treatment modalities hold promise for the future management of this challenging patient population.

From Interferon to Checkpoint Inhibition Therapy-A Systematic Review of New Immune-Modulating Agents in Bacillus Calmette-Guérin (BCG) Refractory Non-Muscle-Invasive Bladder Cancer (NMIBC)

BACKGROUND

In Bacillus Calmette-Guérin (BCG) refractory non-muscle-invasive bladder cancer (NMIBC), radical cystectomy is the gold standard. The advent of immune checkpoint inhibitors (CPIs) has permanently changed the therapy landscape of bladder cancer (BC). This article presents a systematic review of immune-modulating (IM) therapies (CPIs and others) in BCG-refractory NMIBC.

METHODS

In total, 406 articles were identified through data bank research in PubMed/Medline, with data cutoff in October 2021. Four full-text articles and four additional congress abstracts were included in the review.

RESULTS

Durvalumab plus Oportuzumab monatox, Pembrolizumab, and Nadofaragene firadenovec (NF) show complete response (CR) rates of 41.6%, 40.6%, and 59.6% after 3 months, with a long-lasting effect, especially for NF (12-month CR rate of 30.5%). Instillations with oncolytic viruses such as NF and CG0070 show good efficacy without triggering significant immune-mediated systemic adverse events. Recombinant BCG VPM1002BC could prove to be valid as an alternative to BCG in the future. The recombinant pox-viral vector vaccine PANVAC™ is not convincing in combination with BCG. Interleukin mediating therapies, such as ALT-803, are currently being studied.

CONCLUSION

CPIs and other IM agents now offer an increasing opportunity for bladder-preserving strategies. Studies on different substances are ongoing and will yield new findings.

Sequential administration of anti-PD-1 and anti-Tim-3 combined with an SA-GM-CSF-anchored vaccine overcomes adaptive immune resistance to reject established bladder cancer

Program death receptor-1 (PD-1) and T-cell immunoglobulin and mucin domain-containing protein-3 (Tim-3) play an important role in tumor immune evasion. PD-1 blockade could produce an effective anti-tumor effect but the response rate was low due to lacking of tumor infiltrating lymphocytes (TILs) and existing of other negative regulatory pathways. Streptavidin(SA)-GM-CSF surface-anchored tumor cells vaccine could induce specific anti-tumor immune response. However, this vaccine failed to induce regression of established tumor because it also up-regulated PD-1 expression on tumor cells dependent on IFNγ and up-regulated PD-1/Tim-3 expression on CD8⁺ TILs. Subsets of CD8⁺ TILs assay showed that PD-1 expression was closely associated with CD8⁺ TILs exhaustion, and Tim-3 expression was closely correlated with secretion function but not proliferation of CD8⁺ TILs. Sequential administration of anti-PD-1 and anti-Tim-3 could further improve the efficacy of SA-GM-CSF-anchored vaccine therapy, and tumor regression was noted in over 50%. This triple therapy improves the specific cytotoxic activity and decreased the apoptosis of CD8⁺ TILs. These findings indicated that this triple therapy could induce a more robust anti-tumor immune response.

The pilot-scale preparation of the SA-hGM-CSF bi-functional fusion protein

The granulocyte-macrophage colony-stimulating factor (GM-CSF) can be used to induce a powerful immune response. Based on the specific binding of biotin and streptavidin, SA-hGM-CSF was anchored on the surface of biotinylated tumor cells, which could enhance the anti-tumor effect of tumor cell vaccines in our previous reports, suggesting it would have potential clinical value. Preparation of the biologically active proteins in large-scale production is the basis of clinical application, however, only a small amount of biologically active protein was obtained according to previous studies. In this study, we researched the effects of various factors on the purification and simultaneous renaturation of SA-hGM-CSF fusion protein by single factor experiment and orthogonal experiment. Here, we developed a viable pilot-scale trial in the fermentation, purification, refolding and freeze-drying of SA-hGM-CSF proteins in order to efficiently obtain more biologically active proteins with high purity, which will lay the foundation for industrial production.

PD-1 Blockade Overcomes Adaptive Immune Resistance in Treatment with Anchored-GM-CSF Bladder Cancer Cells Vaccine

Purpose: To investigate whether PD-L1 mediated adaptive resistance could occur in treatment with Anchored-GM-CSF vaccine and whether PD-1 blockade combined with Anchored-GM-CSF vaccine could induce a greater anti-tumor immune response than either immunotherapy alone. Materials and Methods: After establishing long-established subcutaneous metastasis bladder cancer models, mice were treated with Anchored-GM-CSF vaccine and/or anti-PD-1 antibody. T-lymphocyte-cytotoxicity, flow cytometric analysis, immunohistochemical, immunofluorescence staining, CD8⁺ -T cell apoptosis and enzyme-linked immunosorbent assays were performed to evaluate the efficacy of combination therapy with anchored-GM-CSF vaccine and PD-1 blockade and to explore the related mechanism. Results: Anchored-GM-CSF vaccine could significantly increase the number of mature DCs and up-regulate PD-L1 expression dependent on IFN-γ released from CD8⁺ T cells. Anchored-GM-CSF vaccine combined with anti-PD-1 antibody could effectively inhibit tumor growth and even cause regression of the established tumor. More CD4⁺ and CD8⁺ T cells appeared at tumor sites and in peripheral blood in the combination therapy group than in the control groups. Splenocytes from mice of the combination therapy group exhibited the most potent cytotoxicity to MB49 cells. Apoptotic assays showed that PD-1 blockade could significantly reduce CD8⁺ T cells apoptosis. Conclusions: Anchored-GM-CSF vaccines and anti-PD-1 antibodies have synergistic effects in metastatic bladder cancer treatment. PD-1 blockade can overcome immune resistance in treatment with the Anchored-GM-CSF vaccine, while Anchored-GM-CSF vaccine can enhance the efficacy of PD-1 blockade therapy.

Quadruple immunotherapy of Bacillus Calmette-Guérin, interferon, interleukin-2, and granulocyte-macrophage colony-stimulating factor as salvage therapy for non-muscle-invasive bladder cancer

BACKGROUND

Bacillus Calmette-Guérin (BCG) is the most effective initial intravesical therapy for high-grade non-muscle invasive bladder cancer, but many patients still fail. Combination intravesical BCG and interferon (IFN) will salvage some patients but results remain suboptimal.

OBJECTIVE

We hypothesized that further immunostimulation with intravesical interleukin-2 and subcutaneous granulocyte-macrophage colony-stimulating factor may improve response to intravesical BCG and IFN in patient with prior BCG failure(s).

METHODS

A retrospective review was performed. Patients received 6 treatments of quadruple immunotherapy (intravesical solution with one-third dose BCG, 50 million units IFN, and 22 million units interleukin-2, along with a 250-mcg subcutaneous sargramostim injection). Surveillance began 4 to 6 weeks after treatment completion. Patients received maintenance if recurrence-free. Success was defined as no recurrence (bladder or extravesical) and bladder preservation. Analysis was performed by Kaplan-Meier method (P<0.05).

RESULTS

Fifty-two patients received treatment with a median recurrence follow-up of 16.3 months and overall follow-up of 41.8 months. All patients had at least 1 prior BCG failure and 13% had 2 or more prior failures. Only 3 patients (6%) were unable to tolerate full induction. Treatment success was 55% at 1 year, and 53% at 2 years. Thirteen patients (25%) underwent cystectomy at a median time of 17.3 months with disease progression to T2 in 1 patient and T3 in 2 patients. No patients had positive surgical margins or positive lymph nodes.

CONCLUSIONS

In patients with non-muscle-invasive bladder cancer with prior BCG failure, quadruple immunotherapy demonstrated good treatment success in some patients and warrants further evaluation.

Stimulatory versus suppressive effects of GM-CSF on tumor progression in multiple cancer types

Granulocyte-macrophage colony-stimulating factor (GM-CSF, also called CSF-2) is best known for its critical role in immune modulation and hematopoiesis. A large body of experimental evidence indicates that GM-CSF, which is frequently upregulated in multiple types of human cancers, effectively marks cancer cells with a ‘danger flag' for the immune system. In this context, most studies have focused on its function as an immunomodulator, namely its ability to stimulate dendritic cell (DC) maturation and monocyte/macrophage activity. However, recent studies have suggested that GM-CSF also promotes immune-independent tumor progression by supporting tumor microenvironments and stimulating tumor growth and metastasis. Although some studies have suggested that GM-CSF has inhibitory effects on tumor growth and metastasis, an even greater number of studies show that GM-CSF exerts stimulatory effects on tumor progression. In this review, we summarize a number of findings to provide the currently available information regarding the anticancer immune response of GM-CSG. We then discuss the potential roles of GM-CSF in the progression of multiple types of cancer to provide insights into some of the complexities of its clinical applications.

Future directions in bladder cancer immunotherapy: towards adaptive immunity

The clinical management of bladder cancer has not changed significantly in several decades. In particular, intravesical bacillus Calmette-Guérin (BCG) immunotherapy has been a mainstay for high-risk nonmuscle invasive bladder cancer since the late 1970s/early 1980s. This is despite the fact that bladder cancer has the highest recurrence rates of any cancer and BCG immunotherapy has not been shown to induce a tumor-specific immune response. We and others have hypothesized that immunotherapies capable of inducing tumor-specific adaptive immunity are needed to impact bladder cancer morbidity and mortality. This article summarizes the preclinical and clinical development of bladder cancer immunotherapies with an emphasis on the last 5 years. Expected progress in the near future is also discussed.

Evaluation of hGM-CSF/hTNFα surface-modified prostate cancer therapeutic vaccine in the huPBL-SCID chimeric mouse model

To validate its efficacy in the context of the human immune system, a novel therapeutic vaccine of hGM-CSF/hTNFα surface-modified PC-3 cells against human prostate cancer was evaluated in the human peripheral blood lymphocytes-severe combined immunodeficiency (huPBL-SCID) chimeric mouse model. The hGM-CSF or/and hTNFα modified vaccines inhibited prostate cancer growth effectively so as to prolong the mouse survival significantly. The splenocytes from the hGM-CSF/hTNFα vaccine-inoculated mice showed the strongest tumor-specific cytotoxicity against PC-3 cells and the highest production of IFNɤ. These features indicated that type 1 protective immune response was induced efficiently against human prostate cancer and further enhanced through synergetic adjuvant effects of hGM-CSF and hTNFα.

A novel therapeutic vaccine of mouse GM-CSF surface modified MB49 cells against metastatic bladder cancer

PURPOSE

Immunotherapy is considered effective for muscle invasive bladder cancer mini metastasis. We developed what is to our knowledge a novel technology by which streptavidin tagged mouse GM-CSF was displayed on the surface of biotinylated bladder cancer cells to induce antitumor immunity.

MATERIALS AND METHODS

Mouse subcutaneous and lung metastasis bladder cancer models were established. Mice were injected subcutaneously with 1 × 10(6) mouse GM-CSF surface modified MB49 bladder cancer cells and monitored for tumor growth and survival. Immunohistochemical and flow cytometric assay were done to assess the proportion of T lymphocytes. The T-lymphocyte cytotoxicity assay was performed to assess MB49 specific cytotoxicity. On day 60 after MB49 implantation the vaccine cured mice were injected subcutaneously with MB49 or RM-1 cells in the left or right hind leg, respectively. They were monitored for survival and T-lymphocyte cytotoxicity.

RESULTS

Mouse GM-CSF surface modified vaccine significantly inhibited tumor growth in the subcutaneous model and extended survival in the lung model. More CD4 and CD8 T cells appeared at tumor sites and in peripheral blood in the vaccine treated group than in other control groups. Splenocytes from the vaccine treated group showed the most potent cytotoxicity on MB49 cells. Cured mice in the vaccine treated group resisted the second injection of MB49 bladder cancer cells but not the RM-1 prostate cancer cell challenge.

CONCLUSIONS

Mouse GM-CSF surface modified MB49 bladder cancer cell vaccine induced specific antitumor immunity and was efficient for metastatic bladder cancer.

The therapeutic potential of SA-sCD40L in the orthotopic model of superficial bladder cancer

BACKGROUND

Intravesical administration is an important treatment against superficial bladder cancer and CD40L is essential for the protective anti-tumor immunity. In situ gene therapy with CD40L was demonstrated to successfully inhibit tumor cell growth in the orthotopic mouse model of bladder cancer. In the present study, we prepared streptavidin (SA)-tagged sCD40L and developed a novel immunotherapy for superficial bladder cancer based on the strong interaction between streptavidin and biotin.

MATERIAL AND METHODS

The SA-sCD40L fusion protein was expressed in E. coli and purified on the Ni-NTA column. After refolding with dialysis, the bi-function of the fusion protein was determined by flow cytometric analysis for streptaidin-mediated surface modification of MB49 bladder cancer cells and a mouse B cell CD40L-dependent proliferation assay. The mouse orthotopic model of MB49 superficial bladder cancer was used to evaluate the efficacy of SA-sCD40L immunotherapy.

RESULTS

The SA-sCD40L fusion protein exhibited both full biotin-binding property and CD40L bioactivity. After intravesical instillation, the SA-sCD40L bi-functional fusion protein was durably immobilized on the biotinylated mucosal surface of bladder wall for up to four days. The SA-sCD40L treatment significantly prolonged the survival of MB49 tumor-bearing mice and cured 50% of mice with MB49 superficial bladder cancer without significant adverse effects. In addition, more tumor-infiltrating CD4(+)or CD8(+) T cells were observed in SA-sCD40L-treated group.

CONCLUSION

Intravesical immobilization of SA-sCD40L elicited a strong and long-lasting immunity against the MB49 bladder cancer.

Sequential administration of GM-CSF and IL-2 surface-modified MB49 cells vaccines against the metastatic bladder cancer

OBJECTIVES

Many strategies are pursued to enhance tumor vaccine immune response, including the utilization of cytokines. We have developed a novel protein-anchor technology to immobilize cytokines on tumor cell surface. Here we reported the preparation of tumor cell vaccines by immobilizing GM-CSF or IL-2 on MB49 bladder cancer cells and evaluated their antitumor efficacy (administrated alone or sequentially) in a metastatic mouse model.

MATERIALS AND METHODS

SA-mGM-CSF or SA-hIL-2 surface-modified MB49 cells were prepared as vaccine. Mice were treated with MB49 cell vaccines (administrated alone or sequentially). Survival time, tumor growth, flow cytometry, immunohistochemistry, enzyme-linked immunosorbent assay (ELISA), and cytotoxic T lymphocytes (CTL) assay were used to evaluate the antitumor efficiency of the vaccines in the pulmonary metastatic model of bladder cancer.

RESULTS

GM-CSF vaccine induced more mature dendritic cells in the mice spleen. Combination with subsequent IL-2 vaccine significantly increased CD4(+), CD8(+), and IFN-γ(+)CD8(+) T but not CD4(+)Foxp3(+) T cell population and induced the highest production of IFN-γ, IL-12, but not IL-10. Furthermore, the splenocytes from the sequentially combined vaccines group showed the most potent cytotoxicity on MB49 cells. Finally, the sequentially combined vaccines evidently extended the survival time of mice (the median survival time of PBS, ethanol-fixed, anchored GM-CSF, anchored IL-2, and anchored GM-CSF + anchored IL-2 groups were 34, 37, 45, 47, and 59 days, respectively) and effectively protected the mice against a second MB49 cells but not RM-1 cells challenge.

CONCLUSIONS

This study demonstrated that sequential administration of GM-CSF and IL-2 surface-modified MB49 cells vaccines could effectively induce specific antitumor immune response.

Novel immunotherapy for metastatic bladder cancer using vaccine of human interleukin-2 surface-modified MB 49 cells

OBJECTIVE

To develop a novel protein-anchor technology to immobilize human interleukin-2 on tumor cells to induce antitumor immunity.

METHODS

Interleukin-2 surface-modified MB49 cells were prepared as a vaccine. Subcutaneous and pulmonary metastatic mouse models of MB49 bladder cancer were used to evaluate the antitumor efficiency of the vaccine. Immunohistochemistry, flow cytometric, and cytotoxic T-lymphocyte assay were performed to assess the proportion and cytotoxicity of the T lymphocytes.

RESULTS

The IL-2 surface-modified MB49 cell vaccine inhibited tumor growth and extended the survival of the mice, and the vaccine-cured mice effectively resisted the second MB49 but not the RM-1 prostate cancer cell challenge. Furthermore, more cytotoxicity on the MB49 cells and more CD4-positive, CD8-positive T cells appeared in the vaccine-treated group.

CONCLUSION

The results of our study have demonstrated that the human interleukin-2 surface-modified MB49 bladder cancer cell vaccine induced specific antitumor immunity and was efficient against metastatic bladder cancer.

Low-dose paclitaxel enhances the anti-tumor efficacy of GM-CSF surface-modified whole-tumor-cell vaccine in mouse model of prostate cancer

Chemotherapy combined with a tumor vaccine is an attractive approach in cancer therapy. This study was designed to investigate the optimal schedule and mechanisms of action of a novel GM-CSF (granulocyte-macrophage colony-stimulating factor) surface-modified tumor-cell vaccine in combination with paclitaxel in the treatment of mouse RM-1 prostate cancer. First, the anti-tumor efficiencies of various dosage of paclitaxel (4, 20, 40 mg/kg) in combination with the vaccine in different administration sequences were examined in the mouse RM-1 prostate cancer model. Then, the in vivo and in vitro effects of various dosage of paclitaxel on RM-1 cells, T cells, and DCs (dendritic cells) were evaluated. The results showed that: (a) the GM-CSF-surface-modified tumor-cell vaccine was more potent at inducing the uptake of tumor antigens by DCs than irradiated tumor cells plus free GM-CSF; (b) 4 mg/kg paclitaxel combined with the GM-CSF-surface-modified tumor-cell vaccine was the most effective at enhancing tumor regression in RM-1 prostate cancer mice when the vaccine was administrated 2 days after paclitaxel; and (c) administration of 4 mg/kg paclitaxel followed by the vaccine induced the highest degree of CD8(+) T-cell infiltration in tumor tissue, suggesting that the induction of tumor-specific immune response had occurred. These findings suggested that the GM-CSF-surface-modified tumor-cell vaccine may have potential clinical benefit for patients with prostate cancer when it is combined with paclitaxel. Furthermore, the effect of immunochemotherapy depends on careful selection of paclitaxel dosage and the sequence of paclitaxel/vaccine administration.