[Mechanism by which mycobacterial antigen 85B inhibits autophagy and promotes apoptosis in Hodgkin lymphoma cells].

OBJECTIVES

To investigate the mechanism by which mycobacterial antigen 85B (Ag85B) inhibits autophagy and promotes apoptosis in Hodgkin lymphoma (HL) cells.

METHODS

The clinical data and pathological tissue slides were retrospectively collected from 80 HL children and 30 children with reactive lymphadenopathy (control group) treated at the First Affiliated Hospital of Xinjiang Medical University. Immunohistochemical analysis was performed to assess the expression of microtubule-associated protein 1 light chain 3 (LC3), sequestosome 1 (P62/SQSTM1), and Beclin-1 in the pathological tissues of HL and control groups. Human Hodgkin lymphoma cells (HDLM-2) were divided into the HDLM-2 group and the HDLM-2+Ag85B groups (with Ag85B concentrations of 0.5, 1, 2, and 4 μg/mL). The CCK8 method was used to measure HDLM-2 cell proliferation; qRT-PCR was employed to detect the expression of LC3, P62, Beclin-1, Akt, and mTOR mRNA in cells. An apoptosis kit was used to detect cell apoptosis.

RESULTS

The positive expression of LC3 and Beclin-1 in the HL group were higher than those in the control group (<0.05), while the positive expression of P62 was lower than that in the control group (<0.05). In stages III-IV compared to stages I-II, the positive expression of LC3 and Beclin-1 increased, while the positive expression of P62 decreased (<0.05). Cell experiment results showed that the HDLM-2+Ag85B group had suppressed cell proliferation compared to the HDLM-2 group, with decreased mRNA expression of LC3 and Beclin-1, and increased mRNA expression of P62, PI3K, Akt, and mTOR, leading to increased cell apoptosis. Notably, when Ag85B was at a concentration of 2 μg/mL, it had the strongest effect on HDLM-2 cells after 24 hours (<0.05).

CONCLUSIONS

Autophagy is enhanced in children with HL and increases with disease stage. Ag85B can inhibit the proliferation and autophagy of HL tumor cells and promote apoptosis, possibly related to the activation of the PI3K/Akt/mTOR pathway.