Single-cell transcriptome sequencing reveals aberrantly activated inter-tumor cell signaling pathways in the development of clear cell renal cell carcinoma

BACKGROUND

Aberrant intracellular or intercellular signaling pathways are important mechanisms that contribute to the development and progression of cancer. However, the intercellular communication associated with the development of ccRCC is currently unknown. The purpose of this study was to examine the aberrant tumor cell-to-cell communication signals during the development of ccRCC.

METHODS

We conducted an analysis on the scRNA-seq data of 6 ccRCC and 6 normal kidney tissues. This analysis included sub clustering, CNV analysis, single-cell trajectory analysis, cell-cell communication analysis, and transcription factor analysis. Moreover, we performed validation tests on clinical samples using multiplex immunofluorescence.

RESULTS

This study identified eleven aberrantly activated intercellular signaling pathways in tumor clusters from ccRCC samples. Among these, two of the majors signaling molecules, MIF and SPP1, were mainly secreted by a subpopulation of cancer stem cells. This subpopulation demonstrated high expression levels of the cancer stem cell markers POU5F1 and CD44 (POU5F1hiCD44hiE.T), with the transcription factor POU5F1 regulating the expression of SPP1. Further research demonstrated that SPP1 binds to integrin receptors on the surface of target cells and promotes ccRCC development and progression by activating potential signaling mechanisms such as ILK and JAK/STAT.

CONCLUSION

Aberrantly activated tumor intercellular signaling pathways promote the development and progression of ccRCC. The cancer stem cell subpopulation (POU5F1hiCD44hiE.T) promotes malignant transformation and the development of a malignant phenotype by releasing aberrant signaling molecules and interacting with other tumor cells.

Abstract 5690: The landscape of homologous recombination repair gene mutations and prognosis in Chinese patients with clear cell renal cell carcinoma

Background: Clear cell renal cell carcinoma (ccRCC) is the most common subtype of kidney cancer with poor prognosis. Mutations in homologous recombination repair (HRR) genes are associated with human tumorigenesis and response to DNA-damage-inducing therapeutics, such as platinum agents and PARP inhibitors. A better understanding of the genomic features of HRR pathway genes and its correlations with prognosis will facilitate precise personalized treatment selection.

Methods: Tumor tissues and matched blood were collected from 269 ccRCC patients at the 3rd Affilated Teaching Hospital of Xinjiang Medical University(Affiliated Tumor Hospital) from 2011 to 2017. A panel targeting 450 cancer-related gene test was performed at OrigiMed (Shanghai, China). Using targeted capture genomic sequencing, we assessed patients for germline and somatic mutations in 23 HRR related genes. Survival analysis was performed using a Cox proportional hazards model and the p-value was determined with a log-rank test.

Results: In total, 269 ccRCC patients, including 95 females and 174 males with a median age of 55 (range 21-87 years old), were recruited. Fifty patients developed distant metastases. The most frequently mutated genes were VHL (83%) and PBRM1 (38%). The median tumor mutational burden (TMB) of this cohort was 4 muts/Mb (0-43.9 muts/Mb), and 4.1% (11/269) of patients displayed high TMB (defined as ≥ 10 muts/Mb). HRR pathway gene mutations were detected in 90/269 patients (33.46%). The most frequently altered genes were BAP1(13.4%), ARID1A (5.2%), BRCA1 (3.72%), ATM (3.35%), and BRCA2 (1.86%). Truncation (23.05%) was the most common mutation type. 4.46% (12/269) of patients carried HRR-related germline mutations, and the most frequently mutated germline genes were RAD51C/D (33.33%,4/9) and BRCA (16.67%, 2/9). Patients with HRR pathway gene mutations were found to have a significantly higher TMB (median, 4.45 vs. 4 muts/Mb, p < 0. 05). We additionally identified that mutations in HRR pathways were significantly associated with decreased relapse-free survival (RFS)( p < 0.05). The 3-year RFS rate of the HRR-mutated group was significantly lower than the negative group (78.8% vs.90.6%, p<0.01).

Conclusion: HRR gene alterations, associated with increased recurrence, occurred at a high frequency of 33.46% in Chinese ccRCC patients. Further studies regarding to therapeutic agents targeting the HRR pathway in this population should be considered in the future.

Citation Format: Peng Chen, Yuan Zhang, Xing Bi, Yue Niu, Fuerhaiti Shayiti, Shuai Yuan, Ting Pan, Yan Wang. The landscape of homologous recombination repair gene mutations and prognosis in Chinese patients with clear cell renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5690.

Tumor-associated macrophage-derived CCL5 promotes chemotherapy resistance and metastasis in prostatic cancer

The crosstalk between tumor microenvironment and cancer cells is emerging as a critical determinant in tumor progression. However, the underlying mechanism of tumor microenvironment-induced cancer development remains controversial. Here, our study provides evidence to suggest that tumor-associated macrophage (TAM) enrichment is found in chemoresistant prostatic tumor tissues. Those TAMs are demonstrated to promote chemoresistance and distant metastasis in prostatic cancer through secretion of CCL5. Mechanistically, TAM coculture or additional CCL5 can mediate the STAT3-dependent epithelial-mesenchymal transition process, resulting in distant metastasis in prostatic cancer. Meanwhile, activation of STAT3 induced by CCL5 can mediate upregulation of the transcription factor Nanog, leading to drug resistance. In vivo study further demonstrated that blockade of STAT3 signals significantly reverses chemoresistance and suppresses lung metastasis in colorectal tumor-bearing mice, suggesting a novel strategy for clinical prostatic cancer treatment.