Detection and prognostic significance of isolated tumor cells and micrometastases in pelvic lymph nodes of patients with early ovarian clear cell carcinoma

Inhibition of nucleophosmin/B23 sensitizes ovarian cancer cells to immune check-point blockade via PD-L1 in ovarian cancer

BACKGROUND

Immune checkpoint inhibitors (ICIs) that against programmed cell death protein-1 (PD-1) and its ligand PD-L1 have been approved as a promising treatment of many human cancers. However, the responses to these ICIs were limited in patients with ovarian cancer. Studies have indicated that the response to PD-1/PD-L1 blockade might be correlated with the PD-L1 expression level in cancer cells. Nucleophosmin (NPM/B23) was found to be a potential target for immunotherapy. Whether NPM/B23 plays a role in cancer-associated immunity, such as PD-1/PD-L1 axis, and its underlying mechanisms remain largely unknown in ovarian cancer.

METHODS

We applied ovarian cancer cell lines as research models. The effect of modulating PD-L1 by NPM/B23 was subsequently confirmed via Western blot, flow cytometry, qRT-PCR, luciferase reporter assays, and immunoprecipitation. Protein stability and ubiquitin assay assays were used to analyze the interplay between NPM/B23 and NF-ĸB/p65 in PD-L1 regulation. The MOSEC/Luc xenograft mouse model was used to validate the role of NPM/B23-PD-L1 through tumor growth in vivo.

RESULTS

Our results revealed that NPM/B23 negatively regulates PD-L1 expression via a protein complex with NF-κB/p65 and through an IFN-γ pathway. Moreover, NPM/B23 inhibitor/modulator sensitized ovarian cancer cells to the anti-PD-1 antibody by regulating PD-L1 expression in the immunocompetent mouse model. Compared to anti-PD-1 antibody alone, a combination of anti-PD-1 antibody and NPM/B23 inhibitor/modulator showed reduced tumorigenesis and increased CD8+ T-cell expansion, thus contributing to prolonged survival on MOSEC/Luc-bearing mouse model.

CONCLUSION

Targeting NPM/B23 is a novel and potential therapeutic approach to sensitize ovarian cancer cells to immunotherapy.

Precisional detection of lymph node metastasis using tFCM in colorectal cancer

The detection of colorectal cancer (CRC) lymph node (LN) metastases significantly influences treatment choices, yet identifying them in samples is time-consuming and error-prone. To enhance efficiency, we have established a LN metastasis detection method utilizing triple-parameter flow cytometry (tFCM) and have conducted a comparative assessment of its accuracy and cost-effectiveness in contrast to conventional pathological examinations. This technique utilized biomarkers cytokeratin 20 (CK20), epithelial cell adhesion molecules (EpCAM), and Pan-CK. tFCM's sensitivity was validated by analyzing known cell line concentrations (SW480 and SW620) in peripheral blood mononuclear cells (PBMCs), with CK20, EpCAM, and Pan-CK showing significant expression in CRC cell lines but not in PBMCs. A strong linear correlation was observed in the mixed leukocyte environment (R 2 = 0.9988). Subsequently, tFCM and pathological sections were employed to analyze LNs from CRC patients, enabling comparison of detection accuracy. Within the 36 LNs studied, tFCM successfully identified tumor cells with varying metastasis degrees, including micro-metastasis and isolated tumor cell clusters. Notably, relying solely on pathological sections led to a potential 25% misdiagnosis rate for LNs. In contrast, tFCM effectively minimized this risk. In summary, compared to traditional pathological sections, tFCM is a more advantageous method for detecting nodal metastasis in CRC patients, offering a more precise prognosis for these patients.