Bovine dialyzable leukocyte extract modulates AP-1 DNA-binding activity and nuclear transcription factor expression in MCF-7 breast cancer cells

Immunotherapies inducing immunogenic cell death in cancer: insight of the innate immune system

Cancer immunotherapies include monoclonal antibodies, cytokines, oncolytic viruses, cellular therapies, and other biological and synthetic immunomodulators. These are traditionally studied for their effect on the immune system's role in eliminating cancer cells. However, some of these therapies have the unique ability to directly induce cytotoxicity in cancer cells by inducing immunogenic cell death (ICD). Unlike general immune stimulation, ICD triggers specific therapy-induced cell death pathways, based on the release of damage-associated molecular patterns (DAMPs) from dying tumour cells. These activate innate pattern recognition receptors (PRRs) and subsequent adaptive immune responses, offering the promise of sustained anticancer drug efficacy and durable antitumour immune memory. Exploring how onco-immunotherapies can trigger ICD, enhances our understanding of their mechanisms and potential for combination strategies. This review explores the complexities of these immunotherapeutic approaches that induce ICD, highlighting their implications for the innate immune system, addressing challenges in cancer treatment, and emphasising the pivotal role of ICD in contemporary cancer research.

IMMUNEPOTENT CRP induces DAMPS release and ROS-dependent autophagosome formation in HeLa and MCF-7 cells

Background

IMMUNEPOTENT CRP (ICRP) can be cytotoxic to cancer cell lines. However, its widespread use in cancer patients has been limited by the absence of conclusive data on the molecular mechanism of its action. Here, we evaluated the mechanism of cell death induced by ICRP in HeLa and MCF-7 cells.

Methods

Cell death, cell cycle, mitochondrial membrane potential and ROS production were evaluated in HeLa and MCF-7 cell lines after ICRP treatment. Caspase-dependence and ROS-dependence were evaluated using QVD.oph and NAC pre-treatment in cell death analysis. DAMPs release, ER stress (eIF2-α phosphorylation) and autophagosome formation were analyzed as well. Additionally, the role of autophagosomes in cell death induced by ICRP was evaluated using SP-1 pre-treatment in cell death in HeLa and MCF-7 cells.

Results

ICRP induces cell death, reaching CC₅₀ at 1.25 U/mL and 1.5 U/mL in HeLa and MCF-7 cells, respectively. Loss of mitochondrial membrane potential, ROS production and cell cycle arrest were observed after ICRP CC₅₀ treatment in both cell lines, inducing the same mechanism, a type of cell death independent of caspases, relying on ROS production. Additionally, ICRP-induced cell death involves features of immunogenic cell death such as P-eIF2α and CRT exposure, as well as, ATP and HMGB1 release. Furthermore, ICRP induces ROS-dependent autophagosome formation that acts as a pro-survival mechanism.

Conclusions

ICRP induces a non-apoptotic cell death that requires an oxidative stress to take place, involving mitochondrial damage, ROS-dependent autophagosome formation, ER stress and DAMPs’ release. These data indicate that ICRP could work together with classic apoptotic inductors to attack cancer cells from different mechanisms, and that ICRP-induced cell death might activate an immune response against cancer cells.

Bovine Dialyzable Leukocyte Extract IMMUNEPOTENT-CRP Induces Selective ROS-Dependent Apoptosis in T-Acute Lymphoblastic Leukemia Cell Lines

Immunotherapies strengthen the immune system to fight multiple diseases such as infections, immunodeficiencies, and autoimmune diseases, and recently, they are being used as an adjuvant in cancer treatment. IMMUNEPOTENT-CRP (I-CRP) is an immunotherapy made of bovine dialyzable leukocyte extract (bDLE) that has chemoprotective and immunomodulatory effects in different cellular populations of the immune system and antitumor activity in different cancer cell lines. Our recent results suggest that the antineoplastic effect of I-CRP is due to the characteristics of cancer cells. To confirm, we evaluated whether the selectivity is due to cell lineage or characteristics of cancer cells, testing cytotoxicity in T-acute lymphoblastic leukemia cells and their cell death mechanism. Here, we assessed the effect of I-CRP on cell viability and cell death. To determine the mechanism of cell death, we tested cell cycle, mitochondrial and nuclear alterations, and caspases and reactive oxygen species (ROS) and their role in cell death mechanism. Our results show that I-CRP does not affect cell viability in noncancer cells and induces selective cytotoxicity in a dose-dependent manner in leukemic cell lines. I-CRP also induces mitochondrial damage through proapoptotic and antiapoptotic protein modulation (Bax and Bcl-2) and ROS production, nuclear alterations including DNA damage (γ-H2Ax), overexpression of p53, cell cycle arrest, and DNA degradation. I-CRP induced ROS-dependent apoptosis in leukemic cells. Overall, here, we show that I-CRP cytotoxicity is selective to leukemic cells, inducing ROS-dependent apoptosis. This research opens the door to further exploration of their role in the immune system and the cell death mechanism that could potentially work in conjunction with other therapies including hematological malignances.

Cytotoxic activity of IMMUNEPOTENT CRP against non-small cell lung cancer cell lines

BACKGROUND

IMMUNEPOTENT-CRP® (I-CRP) is a bovine dialyzable leukocyte extract containing transfer factor. It is a cost-effective, unspecific active immunotherapy that has been used in patients with non-small cell lung cancer (NSCLC) as an adjuvant to reduce the side-effects of chemotherapy and radiotherapy, and has shown cytotoxic activity in vitro on different cancer cell lines. However, its mechanism of action against lung cancer cells has not been assessed. Therefore, the objective of this work was to assess the cytotoxic mechanism of I-CRP on lung cancer cell lines.

METHODS

We assessed cell viability through MTT assay on the NSCLC cell lines A549, A427, Calu-1, and INER-51 after treatment with I-CRP. To further understand the mechanisms of cell viability diminution we used fluorescence-activated cell sorting to evaluate cell death (annexin-V and propidium iodide [PI] staining), cell cycle and DNA degradation (PI staining), mitochondrial alterations (TMRE staining), and reactive oxygen species (ROS) production (DCFDA staining). Additionally, we evaluated caspase and ROS dependence of cell death by pretreating the cells with the pan-caspase inhibitor Q-VD-OPH and the antioxidant N-acetylcysteine (NAC), respectively.

RESULTS

Our data shows that I-CRP is cytotoxic to NSCLC cell lines in a dose and time dependent manner, without substantial differences between the four cell lines tested (A549, A427, Calu-1, and INER-51). Cytotoxicity is induced through regulated cell death and cell cycle arrest induction. I-CRP-induced cell death in NSCLC cell lines is characterized by DNA degradation, mitochondrial damage, and ROS production. Moreover, cell death is independent of caspases but relies on ROS production, as it is abrogated with NAC.

CONCLUSION

Altogether, these results improve the knowledge about the cytotoxic activity of I-CRP on NSCLC cells, indicating that cell death, cell cycle arrest, DNA degradation and mitochondrial damage are important features, while ROS play the main role for I-CRP mediated cytotoxicity in lung cancer cells.

IMMUNEPOTENT CRP induces cell cycle arrest and caspase-independent regulated cell death in HeLa cells through reactive oxygen species production

BACKGROUND

Regulated cell death (RCD) is a mechanism by which the cell activates its own machinery to self-destruct. RCD is important for the maintenance of tissue homeostasis and its deregulation is involved in diseases such as cervical cancer. IMMUNEPOTENT CRP (I-CRP) is a dialyzable bovine leukocyte extract that contains transfer factors and acts as an immunomodulator, and can be cytotoxic to cancer cell lines and reduce tumor burden in vivo. Although I-CRP has shown to improve or modulate immune response in inflammation, infectious diseases and cancer, its widespread use has been limited by the absence of conclusive data on the molecular mechanism of its action.

METHODS

In this study we analyzed the mechanism by which I-CRP induces cytotoxicity in HeLa cells. We assessed cell viability, cell death, cell cycle, nuclear morphology and DNA integrity, caspase dependence and activity, mitochondrial membrane potential, and reactive oxygen species production.

RESULTS

I-CRP diminishes cell viability in HeLa cells through a RCD pathway and induces cell cycle arrest in the G2/M phase. We show that the I-CRP induces caspase activation but cell death induction is independent of caspases, as observed by the use of a pan-caspase inhibitor, which blocked caspase activity but not cell death. Moreover, we show that I-CRP induces DNA alterations, loss of mitochondrial membrane potential, and production of reactive-oxygen species. Finally, pretreatment with N-acetyl-L-cysteine (NAC), a ROS scavenger, prevented both ROS generation and cell death induced by I-CRP.

CONCLUSIONS

Our data indicate that I-CRP treatment induced cell cycle arrest in G2/M phase, mitochondrial damage, and ROS-mediated caspase-independent cell death in HeLa cells. This work opens the way to the elucidation of a more detailed cell death pathway that could potentially work in conjunction with caspase-dependent cell death induced by classical chemotherapies.

The novel immunomodulator IMMUNEPOTENT CRP combined with chemotherapy agent increased the rate of immunogenic cell death and prevented melanoma growth

Immunogenic cell death is a cell death modality that stimulates the immune system to combat cancer cells. IMMUNEPOTENT CRP (ICRP) is a mixture of substances of low molecular weight obtained from bovine spleens that exhibits in vitro cytotoxic activity on different tumor cell lines and modulates the immune response in vivo. The aim of the present study was to determine whether the cytotoxic effect of ICRP and its combination with oxaliplatin (OXP) on murine melanoma B16F10 cells was due to immunogenic cell death. The cytotoxic assay was performed using flow cytometry to detect Annexin V and propidium iodide staining, and calreticulin (CRT) exposure. Adenosine triphosphate, heat shock protein (HSP) 70, HSP90 and high mobility group box 1 (HMGB1) release were identified using bioluminescence, western blot and ELISA assays, respectively. The present in vitro study demonstrated that treatments with ICRP or OXP induced cell death in a time-dependent manner, but treatment with the combination of ICRP + OXP increased the cytotoxic effect following 24 h of treatment. CRT exposure and release of adenosine triphosphate (ATP), HSP70, HSP90 and HMGB1 were induced by treatment with ICRP, and the combination of ICRP + OXP increased the exposure and release of damage-associated molecular patterns (DAMPs), while OXP treatment only induced CRT exposure, ATP and HMGB1 release. The in vivo experiments demonstrated that administration of tumor-derived DAMP-rich cell lysates derived from B16F10 cells treated with ICRP and the combination of ICRP + OXP prevented melanoma growth; however, OXP treatment did not. These results suggested that IMMUNEPOTENT CRP may be used as an agent to increase the ability of antitumor drugs to induce immunogenic cell death and prevent the growth of melanoma.

Anti-Inflammatory Effect of Dialyzable Leukocyte Extract in Autoimmune Prostatitis: Evaluation in Animal Model

Objective. To evaluate the anti-inflammatory properties of Dialyzable Leukocyte Extract (DLE) in a murine model of chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). Methods. Histopathological characterization, prostatein Enzyme-Linked Immunosorbent Assay, and immunohistochemical analysis for CD45, TNF-α, IFN-γ, IL-6, IL-17, and IL-4 molecules were done in prostatic Wistar rats treated with DLE, placebo, or Dexamethasone. Results. Histopathological analysis of animals induced to prostatitis showed inflammatory infiltrate, mainly constituted by leucocytes and mast cells as well as Benign Prostatic Hyperplasia. Serum prostatein concentrations were 14 times higher than those displayed by healthy animals. After DLE and Dexamethasone treatments, the inflammatory infiltrate decreased; the tissue morphology was similar to that of a normal prostate, and the prostatein decreased to the basal levels of healthy animals. DLE treatment produced a decreased expression of the cell surface marker CD45 and the proinflammatory cytokines TNF-α, IFN-γ, IL-6, and IL-17. On the other hand, the expression of anti-inflammatory cytokine IL-4 increased in both the Dexamethasone and DLE groups. Conclusion. DLE is able to modulate the inflammatory response in Experimental Autoimmune Prostatitis (EAP).

Immodin and its immune system supportive role in paclitaxel therapy of 4T1 mouse breast cancer

It is evident that standard chemotherapy agents may have an impact on both tumor and host immune system. Paclitaxel (PTX), a very potent anticancer drug from a taxane family, has achieved prominence in clinical oncology for its efficacy against a wide range of tumors including breast cancer. However, significant toxicity, such as myelosuppression, limit the effectiveness of Paclitaxel-based treatment regimens. Immodin (IM) is low molecular dialysate fraction of homogenate made from human leukocytes. It contains a mixture of substances from which so far have been described e.g. Imreg 1 and Imreg 2 formed by the dipeptide tyrosine-glycine and the tripeptide tyrosine-glycine-glycine, respectively. The aim of this study was to explore immunopharmacological activities of IM, using the strongly immunogenic 4T1 mouse breast cancer model, and evaluate its effect on the reactivity and the efficiency of PTX cancer therapy. The results highlight a potentially beneficial role for IM in alleviating PTX-induced toxicity, especially on the nonspecific immunity, during breast cancer therapy. Co-treatment exhibited an antitumor effect including reduced tumor growth, prolonged survival of tumor bearing mice, increased number of monocytes and lymphocytes in peripheral blood. In spleens, IM+PTX therapy elevated proportion of whole lymphocytes in the account of myelo-monocytic cells characteristic with low expression of CD11c+ and bearing Fc receptor (CD16/32) as well as T-lymphocytes, NK cells and dendritic cells. Accumulation of tumor-associated granulocytes in stroma of PTX-treated group and intensive 4T1-necrosis/apoptosis in tumors after co-treatment were also recorded. These findings suggest the possibility of using IM alongside PTX treatment for maintaining the immune system functions and increasing patient survival.

Effect of bovine dialyzable leukocyte extract on induction of cell differentiation and death in K562 human chronic myelogenous leukemia cells

Differentiation induction therapy is an attractive approach in leukemia treatment due to the fact that in blast crisis stage, leukemic cells lose their differentiation capacity. Therefore, it has been proposed as a therapeutic strategy to induce terminal differentiation of leukemic blast cells into a specific lineage, leading to prevention of high proliferation rates. The aim of the present study was to demonstrate the potential of cell differentiation and death induced by bovine dialyzable leukocyte extract (bDLE) in the K562 cell line. For this purpose K562 and MOLT-3 human leukemic cell lines and primary human monocytes and murine peritoneal macrophages were exposed to bDLE, phorbol myristate acetate (PMA) and dimethyl sulfoxide for 96 h, and the viability, proliferation and cell cycle were evaluated. To determine the lineage that led to cell differentiation, Romanowsky staining was performed to observe the morphological changes following the treatments, and the expression of the surface markers cluster of differentiation (CD)14⁺, CD68⁺, CD163⁺ and CD42a⁺, as well as the phagocytic activity, and the production of nitric oxide (NO) (assessed by colorimetric assay), cytokines [interleukin (IL)-1β, IL-6, IL-8 and tumor necrosis factor-α] and chemokines [chemokine (C-C motif) ligand (CCL)2, CCL5 and chemokine (C-X-C motif) ligand 8] in cell supernatants was assessed by flow cytometry. The results of the present study reveal that high doses of bDLE increase the cell death in K562 and MOLT-3 lines, without affecting the viability of human monocytes and murine peritoneal macrophages. Furthermore, low doses of bDLE induce differentiation in K562 cells towards a monocyte/macrophage lineage with an M2 phenotype, and induced moderately upregulated expression of CD42⁺, a megakaryocytic marker. Cell cycle arrest in the S and G₂/M phases was observed in bDLE-treated K562 cells, which demonstrated similar phagocytic activity, NO levels and cytokine and chemokine production to that of PMA-treated cells. The present study demonstrates that bDLE exhibits an antileukemia effect, suggesting that it may be an effective candidate for leukemia treatment.

Antiviral mode of action of bovine dialyzable leukocyte extract against human immunodeficiency virus type 1 infection

BACKGROUND

Bovine dialyzable leukocyte extract (bDLE) is derived from immune leukocytes obtained from bovine spleen. DLE has demonstrated to reduce transcription of Human Immunodeficiency Virus Type 1 (HIV-1) and inactivate the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway. Therefore, we decided to clarify the mode of antiviral action of bDLE on the inhibition of HIV-1 infection through a panel of antiviral assays.

RESULTS

The cytotoxicity, HIV-1 inhibition activity, residual infectivity of bDLE in HIV-1, time of addition experiments, fusion inhibition of bDLE for fusogenic cells and the duration of cell protection even after the removal of bDLE were all assessed in order to discover more about the mode of the antiviral action.HIV-1 infectivity was inhibited by bDLE at doses that were not cytotoxic for HeLa-CD4-LTR-β-gal cells. Pretreatment of HIV-1 with bDLE did not decrease the infectivity of these viral particles. Cell-based fusion assays helped to determine if bDLE could inhibit fusion of Env cells against CD4 cells by membrane fusion and this cell-based fusion was inhibited only when CD4 cells were treated with bDLE. Infection was inhibited in 80% compared with the positive (without EDL) at all viral life cycle stages in the time of addition experiments when bDLE was added at different time points. Finally, a cell-protection assay against HIV-1 infection by bDLE was performed after treating host cells with bDLE for 30 minutes and then removing them from treatment. From 0 to 7 hours after the bDLE was completely removed from the extracellular compartment, HIV-1 was then added to the host cells. The bDLE was found to protect the cells from HIV-1 infection, an effect that was retained for several hours.

CONCLUSIONS

bDLE acted as an antiviral compound and prevented host cell infection by HIV-1 at all viral life cycle stages. These cell protection effects lingered for hours after the bDLE was removed. Interestingly, bDLE inhibited fusion of fusogenic cells by acting only on CD4 cells. bDLE had no virucidal effect, but could retain its antiviral effect on target cells after it was removed from the extracellular compartment, protecting the cells from infection for hours.bDLE, which has no reported side effects or toxicity in clinical trials, should therefore be further studied to determine its potential use as a therapeutic agent in HIV-1 infection therapy, in combination with known antiretrovirals.

Clinical and immunological assessment in breast cancer patients receiving anticancer therapy and bovine dialyzable leukocyte extract as an adjuvant

Dialyzable leukocyte extract (DLE) is one of the immunological agents used as an adjuvant in cancer therapy; it has been associated with improved quality of life during cancer chemotherapy. Based on these previous findings and on the observed clinical benefits attributed to DLE in other types of cancer, we investigated its clinical and immunological effects as a therapy adjuvant on breast cancer patients who received only chemotherapy, as compared to patients administered bovine DLE (bDLE) as an adjuvant. This study included 43 breast cancer patients who were about to begin chemotherapy. This group was divided as follows: 25 received chemotherapy and bDLE as an adjuvant therapy, and 18 received only chemotherapy without the adjuvant. All patient clinical and immunological responses were monitored. Among patients in the group that received bDLE as adjuvant, 60% showed a complete response, 32% showed a partial response and 8% did not respond. By contrast, in the group without the adjuvant, 39% showed a complete response, 50% displayed a partial response and 11% were non-responders. In addition, bDLE treatment in combination with chemotherapy resulted in the enhancement of the Karnofsky performance scale during chemotherapy. Even though patients underwent several cycles of chemotherapy without bDLE, the lymphocyte population dropped to below the reference value. On the other hand, in patients with bDLE as adjuvant, the CD4(+) and CD8(+) lymphocytes and the B lymphocytes were maintained within the median range of the reference value. The number of natural killer cells also increased after chemotherapy treatment with bDLE as an adjuvant. In conclusion, bDLE treatment contributes to significant immunological recovery in patients that have undergone heavy chemotherapy, increasing the clinical response and quality of life during chemotherapy.

Antiangiogenic and antitumor effects of IMMUNEPOTENT CRP in murine melanoma

BACKGROUND

Skin cancers are common, and there has recently been a dramatic increase in their incidence, particularly in the occurrence of melanoma. Furthermore, relapse after curative surgical treatment of melanoma remains a significant clinical challenge and accounts for most of the mortality of this disease.

OBJECTIVE

The aim of this study was to determine whether IMMUNEPOTENT CRP affects B16F10 melanoma cells and tumors growth and vascular endothelial growth factor (VEGF) production in vivo and in vitro.

METHODS

B16F10 cells and B16F10-inoculated mice were treated with different concentrations of IMMUNEPOTENT CRP. Outcomes were then evaluated using MTT, TUNEL, Caspase-3, senescence, ELISA and colorimetric assays. Parameters related to survival and tumor weight were also assessed.

RESULTS

IMMUNEPOTENT CRP decreased the viability of B16F10 cells by increasing apoptosis of the treated cells, and VEGF production was decreased both in vitro and in vivo. Furthermore, treatment prevented metastasis, delayed the appearance of tumors, decreased tumor weight and improved the survival of tumor-bearing mice.

DISCUSSION

These observations suggest that IMMUNEPOTENT CRP can be used to suppress growth and metastasis by using targeting proteins such as VEGF.