Huaier Induces Immunogenic Cell Death Via CircCLASP1/PKR/eIF2α Signaling Pathway in Triple Negative Breast Cancer

Abstract

Triple-negative breast cancer (TNBC) is the most lethal breast cancer subtype owing to the lack of targeted therapeutic strategies. Immunogenic cell death (ICD), a modality of regulated cancer cell death, offered a novel option for TNBC via augmenting tumor immunogenic microenvironment. However, few ICD-inducing agents are currently available. Here, we showed that Trametes robiniophila Murr (Huaier) triggered ICD in TNBC cells by promoting cell surface calreticulin (CRT) exposure, and increasing release of adenosine triphosphate (ATP) and high-mobility group protein B1 (HMGB1). Co-culturing with Huaier-treated TNBC cells efficiently enhanced the maturation of dendritic cells (DCs), which was further validated via cell-based vaccination assay. In the xenograft mouse model, oral administration of Huaier led to tumor-infiltrating lymphocytes (TILs) accumulation and significantly delayed tumor growth. Besides, depletion of endogenous T cells obviously abrogated the effect. Mechanically, Huaier could elicit endoplasmic reticulum (ER) stress-associated ICD through eIF2α signaling pathway. Further studies revealed that circCLASP1 was involved in the Huaier-induced immunogenicity by binding with PKR in the cytoplasm and thus blocking its degradation. Taken together, we highlighted an essential role of circCLASP1/PKR/eIF2α axis in Huaier-induced ICD. The findings of our study carried significant translational potential that Huaier might serve as a promising option to achieve long-term tumor remission in patients with TNBC.

Expression Profiles and Bioinformatic Analysis of Circular RNAs in Db/Db Mice with Cardiac Fibrosis

“…The overexpression of circCLASP1, the third upregulated circRNA in the present study, greatly enhanced the stimulating effects of Huaier-induced immunogenic cell death. 23 A recent study showed that Wnt7a was also a fibrotic target gene. 24 Interestingly, circCLASP1 was upregulated in bd/db mice with cardiac fibrosis, and may regulate Wnt7a by inhibiting the activity of miR-182-5p.…”

Combination Nano-Delivery Systems Remodel the Immunosuppressive Tumor Microenvironment for Metastatic Triple-Negative Breast Cancer Therapy

“…4T1 cells were treated with free JQ1, free CXB, JQ1/CXB physical mixture, or CS@JQ1/CXB for 24 h, separately. Then, the cells were harvested and lysed with SDS lysis buffer, and the protein concentrations were measured by the BCA protein assay kit. , The cell lysates containing 30 μg protein were separated by SDS-PAGE at 100 V for 1 h and then transferred onto the PVDF membranes under the ice bath conditions at a transfer current of 0.25 A. Afterward, the membranes were incubated with primary antibodies against GAPDH (1:1000), PD-L1 (1:500), COX-2 (1:500), and VEGF (1:500), and secondary horseradish peroxidase-linked antibodies.…”

Microbes mediated immunogenic cell death in cancer immunotherapy

“…This anti‐tumor effect was mainly associated with ER stress‐associated ICD by promoting the exposure to CRT, release of ATP and HMGB1 in TNBC cells. Further study found that the induction of ICD was triggered through circCLASP1/PKR/eIF2α signaling pathway 108 . MHO7 (6‐epi‐ophiobolin G), a small molecule from Aspergillus ustus , elicited cytotoxic effect on TNBC cells at a low IC 50 from 0.96 to 1.75 μM.…”