Single-cell and bulk RNA sequencing reveal heterogeneity and diagnostic markers in papillary thyroid carcinoma lymph-node metastasis

PURPOSE

Papillary thyroid carcinoma (PTC) is characterized by lymph-node metastasis (LNM), which affects recurrence and prognosis. This study analyzed PTC LNM by single-cell RNA sequencing (scRNA-seq) data and bulk RNA sequencing (RNA-seq) to find diagnostic markers and therapeutic targets.

METHODS

ScRNA-seq data were clustered and malignant cells were identified. Differentially expressed genes (DEGs) were identified in malignant cells of scRNA-seq and bulk RNA-seq, respectively. PTC LNM diagnostic model was constructed based on intersecting DEGs using glmnet package. Next, PTC samples from 66 patients were used to validate the two most significant genes in the diagnostic model, S100A2 and type 2 deiodinase (DIO2) by quantitative reverse transcription-polymerase chain reaction (RT-qPCR) and immunohistochemical (IHC). Further, the inhibitory effect of DIO2 on PTC cells was verified by cell biology behavior, western blot, cell cycle analysis, 5-ethynyl-2'-deoxyuridine (EdU) assay, and xenograft tumors.

RESULTS

Heterogeneity of PTC LNM was demonstrated by Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analysis. A total of 19 differential genes were used to construct the diagnostic model. S100A2 and DIO2 differ significantly at the RNA (p < 0.01) and protein level in LNM patient tissues (p < 0.001). And differed in PTC tissues with different pathologic typing (p < 0.001). Further, EdU (p < 0.001) and cell biology behavior revealed that PTC cells overexpressed DIO2 had reduced proliferative capacity. Cell cycle proteins were reduced and cells are more likely to be stuck in G2/M phase (p < 0.001).

CONCLUSIONS

This study explored the heterogeneity of PTC LNM using scRNA-seq. By combining with bulk RNA-seq data, diagnostic markers were explored and the model was established. Clinical diagnostic efficacy of S100A2 and DIO2 was validated and the treatment potential of DIO2 was discovered.

[Primary hypoparathyroidism with basal ganglia calcification: report of a case]

A 3 years old boy was admitted due to recurrent attacks of tetany and carpopedal spasm since one and a half years of age. The tetany lasting for 1-2 minutes in each episode was often preceded by an upper respiratory tract infection and occurred 2-3 times a month. Both birth and family history were unremarkable. Physical findings showed mild psychomotor retardation with positive Chvostek sign. Laboratory examination revealed hypocalcemia, hyperphosphatemia, and low serum parathyroid hormone level. EEG showed abnormal tracing with increased slow waves. Head CT Scan demonstrated symmetrical calcification in the basal ganglia region. The clinical features and laboratory findings were consistent with hypoparathyroidism. The mechanism of calcium deposit in the basal ganglia still remains unclear. Tetany, muscle cramping and seizures secondary to hypocalcemia are the most common neurologic signs which respond quickly to calcium replacement. Subsequent supplemental therapy resolved movement disorders and mental retardation. If early treatment prior to the tetanic episodes is instituted in a patient with hypoparathyroidism, it may prevent the development of complications such as intracranial calcifications, cataract and permanent retardation.