Immunomodulatory potential of anticancer therapy composed of methotrexate nanoconjugate and dendritic cell‑based vaccines in murine colon carcinoma

Abstract

Chemotherapy with low-molecular weight compounds, despite elimination of cancer cells, entails adverse effects. To overcome this disadvantage, innovative drug delivery systems are being developed, including conjugation of macromolecular carriers with therapeutics, e.g. a nanoconjugate of hydroxyethyl starch and methotrexate (HES-MTX). The purpose of the present study was to determine whether HES-MTX, applied as a chemotherapeutic, is able to modulate the immune response and support the antitumor response generated by dendritic cells (DCs) used subsequently as immunotherapeutic vaccines. Therefore, MTX or HES-MTX was administered, as sole treatment or combined with DC-based vaccines, to MC38 colon carcinoma tumor-bearing mice. Alterations in antitumor immune response were evaluated by multiparameter flow cytometry analyses and functional assays. The results demonstrated that the nanoconjugate possesses greater immunomodulatory potential than MTX as reflected by changes in the landscape of immune cells infiltrating the tumor and increased cytotoxicity of splenic lymphocytes. In contrast to MTX, therapy with HES-MTX as sole treatment or combined with DC-based vaccines, contributed to significant tumor growth inhibition. However, only treatment with HES-MTX and DC-based vaccines activated the systemic specific antitumor response. In conclusion, due to its immunomodulatory properties, the HES-MTX nanoconjugate could become a potent anticancer agent used in both chemo-and chemoimmunotherapeutic treatment schemes.

Combined therapy with methotrexate nanoconjugate and dendritic cells with downregulated IL-10R expression modulates the tumor microenvironment and enhances the systemic anti-tumor immune response in MC38 murine colon carcinoma

“…In comparison to the group of mice receiving HES-MTX as sole therapy, the extension of the treatment schedule with multiple peritumoral injections of DC-based vaccines resulted in the enhancement of the local and systemic anti-tumor immune response. However, considering the therapeutic effect of this combined therapy we did not observe the increased tumor growth inhibition, as we initially expected ( 32 ). Therefore, we assumed that other tumor suppressor factors are present in the MC38 tumor microenvironment, such as IL-10, which adversely affects the direction and effectiveness of applied DCs.…”

“…As a result of the conjugation process, HES-MTX nanoconjugate enters cells via folate receptors (FRs), including FRα, which are overexpressed on cancer cells, instead of ubiquitously expressed reduced folate carriers (RFCs), to which MTX in free form has a high affinity ( 31 ). Moreover, taking into account the hydrodynamic diameter of the nanoconjugate molecule (15.2 ± 6.2 nm) as well as the abovementioned prolonged plasma half-life, it may be postulated that the HES-MTX nanoconjugate can reach the tumor tissue through an enhanced vascular permeability and retention effect (EPR), which was discussed in our previous publication ( 32 ).…”

“…Therefore, in our previous research, we demonstrated the greater immunomodulatory potential of HES-MTX nanoconjugate composed of hydroxyethyl starch and MTX in contrast to the free form of MTX in MC38 tumor model ( 32 ). On the third day after HES-MTX administration, we observed the modulation of tumor milieu through the increasing influx of effector cells and eliminating cells with suppressor activity.…”

“…An example of such a novel form of chemotherapeutic delivery is the nanoconjugate of methotrexateone of the oldest antifolate drugs, widely used in anticancer therapy in solid tumors and hematologic malignancies, and hydroxyethyl starchthe amylopectin-based modified polymer applied in medicine as colloidal plasma volume expanders. Through the covalent coupling of MTX and HES, obtained nanoconjugate had a longer plasma half-time compared to the free form of MTX (30), and, importantlyimproved drug biodistribution in the body. As a result of the conjugation process, HES-MTX nanoconjugate enters cells via folate receptors (FRs), including FRa, which are overexpressed on cancer cells, instead of ubiquitously expressed reduced folate carriers (RFCs), to which MTX in free form has a high affinity (31).…”

Recent Reports on Polysaccharide-Based Materials for Drug Delivery

“…An interesting strategy assumes the conjugation of ST-derivative with therapeutics. Hydroxyethyl starch and methotrexate were conjugated and used as a chemotherapeutic for tumor-bearing mice [ 143 ]. The nanoconjugate demonstrated greater immunomodulatory and higher tumor growth inhibition than free methotrexate.…”