GHRH antagonist MIA-602 overcomes Doxorubicin resistance in AML cell lines and xenografts

Acute myeloid leukemia (AML) is an aggressive hematological malignancy characterized by rapid proliferation of mutagenic hematopoietic progenitors, leading to poor prognosis despite conventional chemotherapy and bone marrow transplantation. A significant challenge in AML treatment is the development of resistance to chemotherapeutic agents like Doxorubicin. Growth hormone-releasing hormone (GHRH) can act as an autocrine/paracrine growth factor in various human cancers, including AML. Targeting the GHRH receptor with antagonists like MIA-602 presents a promising strategy to impede cancer growth, potentially offering a novel approach to overcome drug resistance.

Researchers investigated MIA-602 as a monotherapy and in combination with Doxorubicin across three Doxorubicin-resistant human AML cell lines: KG-1A, U-937, and K-562. The study included both wild-type and Doxorubicin-resistant clones of these cell lines for in vitro experiments. Cell viability was assessed as the primary endpoint. For in vivo evaluation, Doxorubicin-resistant K-562 cells were xenografted into nude mice, and the impact of MIA-602 treatment on tumor volume was monitored compared to a control group. The abstract does not specify exact doses or treatment durations for MIA-602.

In vitro results demonstrated a significant reduction in cell viability across all treated wild-type AML cell lines. Crucially, Doxorubicin-resistant clones exhibited similar susceptibility to MIA-602 as their wild-type counterparts, indicating its potential to bypass existing resistance mechanisms. This suggests that MIA-602's mechanism of action is distinct from or overcomes the pathways leading to Doxorubicin resistance. The in vivo experiment, utilizing xenografted nude mice with Doxorubicin-resistant K-562 cells, further supported these findings. MIA-602 treatment led to a reduction in tumor volume compared to the control group, confirming its anti-tumor efficacy in a living system. The study collectively establishes that these three AML cell lines, including their Doxorubicin-resistant variants, are responsive to the GHRH antagonist MIA-602. No specific numerical data (e.g., percentages, p-values, fold-changes) were provided in the abstract for these findings. However, the consistent qualitative outcomes across multiple models are notable.

Doxorubicin-resistant AML cell lines and their wild-type counterparts were similarly susceptible to GHRH antagonist MIA-602, with treatment leading to a significant reduction in cell viability and tumor volume.