Cytoreductive surgery and systemic bacillus Calmette-Guerin therapy in metastatic renal cancer: a phase II trial

Cancer therapy with the viral and bacterial pathogens: The past enemies can be considered the present allies

Cancer continues to be one of the leading causes of mortality worldwide despite significant advancements in cancer treatment. Many difficulties have arisen as a result of the detrimental consequences of chemotherapy and radiotherapy as a common cancer therapy, such as drug inability to penetrate deep tumor tissue, and also the drug resistance in tumor cells continues to be a major concern. These obstacles have increased the need for the development of new techniques that are more selective and effective against cancer cells. Bacterial-based therapies and the use of oncolytic viruses can suppress cancer in comparison to other cancer medications. The tumor microenvironment is susceptible to bacterial accumulation and proliferation, which can trigger immune responses against the tumor. Oncolytic viruses (OVs) have also gained considerable attention in recent years because of their potential capability to selectively target and induce apoptosis in cancer cells. This review aims to provide a comprehensive summary of the latest literature on the role of bacteria and viruses in cancer treatment, discusses the limitations and challenges, outlines various strategies, summarizes recent preclinical and clinical trials, and emphasizes the importance of optimizing current strategies for better clinical outcomes.

Trial watch: FDA-approved Toll-like receptor agonists for cancer therapy

Toll-like receptors (TLRs) have first been characterized for their capacity to detect conserved microbial components like lipopolysaccharide (LPS) and double-stranded RNA, resulting in the elicitation of potent (innate) immune responses against invading pathogens. More recently, TLRs have also been shown to promote the activation of the cognate immune system against cancer cells. Today, only three TLR agonists are approved by FDA for use in humans: the bacillus Calmette-Guérin (BCG), monophosphoryl lipid A (MPL) and imiquimod. BCG (an attenuated strain of Mycobacterium bovis) is mainly used as a vaccine against tuberculosis, but also for the immunotherapy of in situ bladder carcinoma. MPL (derived from the LPS of Salmonella minnesota) is included in the formulation of Cervarix®, a vaccine against human papillomavirus-16 and -18. Imiquimod (a synthetic imidazoquinoline) is routinely employed for actinic keratosis, superficial basal cell carcinoma, and external genital warts (condylomata acuminata). In this Trial Watch, we will summarize the results of recently completed clinical trials and discuss the progress of ongoing studies that have evaluated/are evaluating FDA-approved TLR agonists as off-label medications for cancer therapy.

Bacillus Calmette-Guerin (BCG): Its fight against pathogens and cancer

Bacillus Calmette-Guerin (BCG) is the only FDA approved first line therapy for patients with nonmuscle invasive bladder cancer. Since the turn of the 20th century BCG has been used as a vaccine for protection against Mycobacterium tuberculosis (Mtb) and has also been found to have protection against nontuberculosis related pathogens. Recently the role of "trained immunity" has been identified as a possible mechanism for BCG vaccine-mediated immunity to Mtb. Similarly, BCG has been used as an immunotherapy for bladder cancer for more than 40 years, and the underlying mechanisms for BCG-mediated anti-tumor activity is poorly characterized. Several studies have shown that multiple immune pathways contribute to the immune response, and efficacy of intravesicle BCG as a cancer therapy. It is vital that we integrate our understanding of BCG as a vaccine and as a cancer therapeutic to facilitate design of future studies in order to maximize the immunotherapeutic potential of BCG. In this review we will outline the role of BCG as a vaccine, the known immune pathways that are activated by intravesical BCG and outline a potential clinical study integrating BCG vaccination prior to intravesicle instillation of BCG.

Clinical studies on cell-mediated immunity in patients with renal cell carcinoma: interleukin-2 and interferon-gamma production of lymphocytes

The authors examined interleukin-2 (IL-2) production and interferon gamma (IFN gamma) production of peripheral blood mononuclear cells in 28 patients with renal cell carcinoma and 17 control subjects. The peripheral blood was obtained prior to the initiation of therapeutic procedures. The patients were divided into two groups according to tumor size, less than or equal to 5 cm and greater than 5 cm. The production of IL-2 and IFN gamma was measured by immunoradiometric assay. As a result, in the patients with tumors greater than 5 cm, IL-2 and IFN gamma production was impaired. However, in the patients with tumors less than or equal to 5 cm, IFN gamma production was enhanced, though IL-2 production was not significantly different from that of the control subjects. There was no significant correlation between IL-2 production and IFN gamma production.

Role of immunotherapy in the treatment of bladder and renal cell carcinoma

Much remains to be learned about the immune response in human neoplasia both in a phenomenological sense and in its therapeutic possibilities. Recruitment of immune response mechanisms in the defense against cancer development and in the cure of advanced disease, though theoretically sound, remains to be proven in demonstration of both its phenomenological and clinical efficacy. The most important steps in this regard will require an analysis of those mechanisms that may truly be active in human cancer. Their enhancement and effective delivery to various tumor sites, then reliable monitoring, and proof of their efficacy will be necessary to accomplish before any conclusive statement can be made as to the usefulness of immunotherapy in the treatment of genitourinary neoplasia and of human cancer in general.

In vitro activation of lymphocytes by interleukin 2 in patients with renal cell carcinoma

Interleukin-2-stimulated lymphocytes or lymphokine-activated killer cells (LAK) have been shown to have anti-tumor activity which is not present in the fresh untreated peripheral blood lymphocytes. This activity has been evaluated in our laboratory using renal cell carcinoma as a target tumor. Two of 8 patients demonstrated significant lysis of autologous tumor while an additional 3 patients lysed the target cells but to a less significant degree. It is not clear why the LAK phenomenon against autologous tumors occurs in vitro in some patients and not others. By identifying the response of patients in vitro, one might be able to select an appropriate population for meaningful clinical trials.

Failure of immunotherapy for metastatic renal cell carcinoma

Prompted by reports of tumor regression among patients with metastatic renal cell carcinoma treated by injection of an aggregated autologous or allogeneic tumor antigen with a nonspecific adjuvant, we studied the efficacy of this therapy in 23 patients. Following nephrectomy or excision of a metastatic lesion 16 patients were treated with an aggregated autologous tumor antigen combined with Candida albicans antigen. There were only 2 minimal responses. Seven patients judged unsuitable for an operation were treated with an aggregated allogeneic antigen. There were no objective responses. We conclude that these treatment regimens have minimal activity against metastatic renal cell carcinoma.

Cytotoxic activity of peripheral blood lymphocytes grown with interleukin 2 against autologous cultured tumor cells in patients with renal cell carcinoma: preliminary report

To examine the use of interleukin 2 as a therapeutic agent for human renal cell carcinoma the peripheral blood lymphocytes derived from patients with renal cell carcinoma were grown in interleukin 2 and tested in a 4-hour 51chromium release cytotoxicity assay against autologous cultured tumor cells. Peripheral blood lymphocytes, which were cultured separately in medium alone, mitomycin C-treated tumor cells, 20 per cent interleukin 2 and tumor cells plus interleukin 2, were used as effector cells. In all patients neither peripheral blood lymphocytes in medium alone nor in mitomycin C-treated tumor cells could lyse their own tumor cells. However, in 5 of 7 patients peripheral blood lymphocytes grown in interleukin 2 regardless of the presence of mitomycin C-treated tumor cells were capable of causing 5.7, 9.4, 12.7, 36.1 and 52.5 per cent lysis at effector/target cell ratios of 25, 50, 50, 50 and 25, respectively. However, more significant cytotoxicity was not obtained by peripheral blood lymphocytes cultured with tumor cells and interleukin 2. These results suggest that interleukin 2 might become a useful agent for patients with renal cell carcinoma.

Hormone receptor in renal cell carcinoma and correlation with clinical response to endocrine therapy

Analyses of hormone receptors in cytosols from 41 renal cell carcinoma specimens were performed by the dextran-coated charcoal technique, using estradiol, synthetic progestin R5020 and synthetic androgen R1881. Binding data were calculated according to the method of Scatchard. Of 41 renal cell carcinomas estradiol receptor was detected in 11, R5020 receptor in 11 and R1881 receptor in 13. No significant correlation between histopathological findings and hormone receptors was observed. Patients were classified into those positive and negative for receptors. The clinical response of endocrine therapy for 17 with advanced residual or metastatic lesions after nephrectomy was studied in regard to the survival rates. Although there was no complete or partial regression in tumor size, the survival rate of patients with 1 or more receptors was significantly higher than that of patients negative for receptors (p less than 0.01). In conclusion, hormonal manipulation in patients with renal cell carcinoma cannot induce an antitumor effect but seems to increase survival in patients with receptors.

Autologous mixed lymphocyte tumor cell culture in patients with renal cell carcinoma

Cell-mediated immunity was studied by measurement of lymphocyte response to autologous tumor cells in 19 surgically treated patients with histologically proved (mixed lymphocyte tumor cell culture) renal cell carcinoma. Tumor stage was low in 9 patients and high in 10, while grade was low in 11 and high in 8. Of 8 patients in whom a positive lymphocyte response was detected 6 had high and 2 had low stage tumors (p less than 0.05), while the grade of disease was low in 7 and high in 1 (p less than 0.05). Furthermore, the more advanced and undifferentiated the tumor the more significant the decrease in lymphocyte response (p less than 0.05). Lymphocyte response was positive in 5 of 8 patients with low stage and low grade tumors but negative in 7 with high stage and high grade disease. However, no correlation between the lymphocyte response and the degree of microscopic lymphocytic infiltration in and around the tumor was found. This study confirms that the specific immunological defense mechanism of patients with renal cell carcinoma against the tumors remains well at an earlier stage of tumor development, especially in cases with well differentiated malignancy, and showed attenuation in parallel with pathological spread or in poorly differentiated tumors.