Partitioning defective protein 3 (Par3) has recently been found to have important roles in cancer progression. Interestingly, Par3’s functions vary among cancers: both Par3 elevation (in the prostate or liver) and loss (in the breast or lung) have been implicated in cancer metastasis. Although Par3 overexpression has been correlated with diminished survival in renal cell carcinoma (RCC), data indicating the role of Par3 in RCC metastasis are lacking. Given reports of interactions between Par3 and oncoproteins such as Yes-associated protein (YAP)/WW domain-containing transcription regulator 1 (TAZ), we investigated whether Par3-mediated RCC metastasis might be due to activation of the Hippo pathway components YAP and TAZ.

Par3 levels were analyzed in RCC cell lines and human RCC patient tissues by western blotting and immunohistochemical (IHC) staining, as appropriate. Co-immunoprecipitation (co-IP) and immunofluorescence studies were conducted to examine the interaction between Par3 and YAP. Quantitative PCR and luciferase assays were used to investigate the effects of Par3 on YAP target gene expression and co-transcriptional regulation. PDZ domain deletion mutants of Par3 were generated to elucidate the structural basis of the interaction between Par3 and YAP.

Higher Par3 levels were found in distant-organ-RCC-metastasis-derived ACHN sublines than wild type ACHN cell lines. Par3 levels were also higher in the patient tissue obtained from metastatic sites than in normal kidney and primary RCC tumor tissues. Co-IP and IHC experiments demonstrated that Par3 directly interacted and co-localized with YAP/TAZ proteins. Moreover, Par3 upregulated the transcription of YAP/TAZ downstream target genes and increased the luciferase activity of YAP/TAZ responsive elements. PDZ domain 3 in the PARD3 gene was demonstrated to be particularly important in the interactions between Par3 and YAP. Furthermore, Par3 was found to upregulate intracellular levels of YAP/TAZ molecules and promote nuclear translocation of YAP.

Together, these results indicate the role of Par3 in RCC metastasis, via driving metastatic RCC progression by promoting the YAP/TAZ pathway.

Gemcitabine combined with nab-paclitaxel therapy (GnP) represents first-line chemotherapy for advanced pancreatic ductal adenocarcinoma (PDAC). However, the efficacy of GnP is diminished due to chemotherapeutic resistance induced by the tumor microenvironment (TME), the underlying mechanisms of which remain poorly understood.

Clinical data from patients with PDAC who underwent GnP therapy were collected and neutrophil infiltration in tumor tissues was assessed. PDAC cell lines and a mouse model of PDAC were utilized to determine the mechanisms underlying GnP resistance and to focus on tumor-associated neutrophils and neutrophil extracellular traps (NETs).

GnP therapy recruited neutrophils to the TME, which resulted in the formation of NETs that contributed to therapeutic resistance in the PDAC murine model. The NET inhibitor, PAD4, enhanced the efficacy of GnP by suppressing tumor growth. Furthermore, GnP significantly upregulated CXCL8 secretion in GnP-resistant MIA PaCa-2 cells, which was mediated by increased expression of GPRC5A in PDAC cells. Screening of classic NET-derived molecules identified cell-free DNA (cfDNA) as a pleiotropic factor that promoted tumor cell proliferation and migration and thereby contributed to chemotherapeutic resistance. In vivo experiments revealed that the combination of GnP with siGPRC5A or DNase was more effective in reducing tumor growth and prolonging survival in PDAC-bearing mice than either treatment alone.

The GPRC5A-CXCL8-NET-cfDNA axis has a critical role in the development of therapeutic resistance to GnP in PDAC. Targeting this axis may represent a promising strategy for overcoming GnP resistance and thereby enhancing the efficacy of chemotherapy in PDAC.

While immunotherapy holds great potential for triple-negative breast cancer (TNBC), the lack of non-invasive biomarkers to identify beneficiaries limits the application.

Paired baseline, on-treatment, and post-treatment plasma samples were collected from 195 TNBC patients receiving anti-PD-1 immunotherapy in this retrospective study conducted at the Fudan University Shanghai Cancer Center (FUSCC) for sequential high-precision proteomic profiling.

ARG1, NOS3, and CD28 were identified as plasma proteins significantly associated with the response to immunotherapy in neoadjuvant settings or in advanced stages of TNBC. Matched single-cell RNA sequencing data were incorporated to correlate peripheral plasma with the tumor microenvironment. Furthermore, the Plasma Immuno Prediction Score was developed to demonstrate significant predictive power for evaluating the efficacy and prognosis of patients undergoing neoadjuvant immunotherapy.

The results underscore the importance of systemic immunity in the immunotherapy response and support the use of plasma protein profiles as a feasible tool for enhancing personalized management of immunotherapy in breast cancer.