Haloacetamido analogues of 2-amino-2-deoxy-D-glucose and 2-amino-2-deoxy-D-galactose. Syntheses and effects on the Friend murine erythroleukemia

Targeting the plasma membrane of neoplastic cells through alkylation: a novel approach to cancer chemotherapy

BACKGROUND

Although DNA-directed alkylating agents and related compounds have been a mainstay in chemotherapeutic protocols due to their ability to readily interfere with the rapid mitotic progression of malignant cells, their clinical utility is limited by DNA repair mechanisms and immunosuppression. However, the same destructive nature of alkylation can be reciprocated at the cell surface using novel plasma membrane alkylating agents.

RESULTS

Plasma membrane alkylating agents have elicited long term survival in mammalian models challenged with carcinomas, sarcomas, and leukemias. Further, a specialized group of plasma membrane alkylating agents known as tetra-O-acetate haloacetamido carbohydrate analogs (Tet-OAHCs) potentiates a substantial leukocyte influx at the administration and primary tumor site, indicative of a potent immune response. The effects of plasma membrane alkylating agents may be further potentiated through the use of another novel class of chemotherapeutic agents, known as dihydroxyacetone phosphate (DHAP) inhibitors, since many cancer types are known to rely on the DHAP pathway for lipid synthesis.

CONCLUSION

Despite these compelling data, preliminary clinical trials for plasma membrane-directed agents have yet to be considered. Therefore, this review is intended for academics and clinicians to postulate a novel approach of chemotherapy; altering critical malignant cell signaling at the plasma membrane surface through alkylation, thereby inducing irreversible changes to functions needed for cell survival.

Effects of alkylation and immunopotentiation against Ehrlich ascites murine carcinoma in vivo using novel tetra-O-acetate haloacetamido carbohydrate analogs

Tetra-O-acetate haloacetamido carbohydrate analogs (Tet-OAHCs) are novel alkylating agents that appear to have alkylating activity at the plasma membrane, specificity against neoplastic cells, and may potentiate host leukocyte influx. This study sought to characterize the chemical attributes and in vivo activity of Tet-OAHCs. Four Tet-OAHCs were assessed for their partition coefficient and alkylating activity to determine cellular environments where adduct formation would be favorable. In vitro, IC50 values of all four Tet-OAHCs were determined against Ehrlich ascites murine carcinoma, as well as two leukemias (U937 human monocytic leukemia and L1210 murine lymphoid leukemia) to assess their cytotoxicity in multiple neoplastic cell lines. In vivo, B6D2F1 and CD2F1 mice were challenged i.p. with Ehrlich ascites carcinoma prior to, or after being treated with a single dose of one of the analogs. Finally, a quantitative comparison of host leukocyte influx between Tet-OAHCs and other alkylating agents was performed to confirm previous in vivo observations that the tetra-O-acetate carbohydrate moiety is important for inducing a host leukocyte response in murine models. The results can be summarized as follows: 1) Tet-OAHCs appear to demonstrate high alkylating activity in amphiphilic environments. 2) All four congeners have comparable in vitro cytotoxicities against the neoplastic cell lines examined. 3) The analogs demonstrate marked in vivo activity in both B6D2F1 and CD2F1 mice challenged with a lethal dose of Ehrlich ascites carcinoma, and frequently produce long term survival at 60 days, which is not observed in simple halo derivatives or two currently approved antineoplastic agents (daunorubicin and mechlorethamine). These effects are observed when the agents are administered either before or after the tumor challenge. 4) The carbohydrate moiety appears to be important for potentiating host leukocyte influx, as Tet-OAHCs, but not other alkylating agents demonstrated such activity in vivo.