Rabbit Anti-Human SPTAN1 Polyclonal Antibody

Introduction Colorectal cancers (CRCs) deficient in the DNA mismatch repair protein MutL homolog 1 (MLH1) display distinct clinicopathological features and require a different therapeutic approach compared to CRCs with MLH1 proficiency. However, the molecular basis of this fundamental difference remains elusive. Here, we report that MLH1-deficient CRCs exhibit reduced levels of the cytoskeletal scaffolding protein non-erythroid spectrin alpha II (SPTAN1), and that tumor progression and metastasis of CRCs correlate with SPTAN1 levels. Methods and results To investigate the link between MLH1 and SPTAN1 in cancer progression, a cohort of 189 patients with CRC was analyzed by immunohistochemistry. Compared with the surrounding normal mucosa, SPTAN1 expression was reduced in MLH1-deficient CRCs, whereas MLH1-proficient CRCs showed a significant upregulation of SPTAN1. Overall, we identified a strong correlation between MLH1 status and SPTAN1 expression. When comparing TNM classification and SPTAN1 levels, we found higher SPTAN1 levels in stage I CRCs, while stages II to IV showed a gradual reduction of SPTAN1 expression. In addition, SPTAN1 expression was lower in metastatic compared with non-metastatic CRCs. Knockdown of SPTAN1 in CRC cell lines demonstrated decreased cell viability, impaired cellular mobility and reduced cell-cell contact formation, indicating that SPTAN1 plays an important role in cell growth and cell attachment. The observed weakened cell-cell contact of SPTAN1 knockdown cells might indicate that tumor cells expressing low levels of SPTAN1 detach from their primary tumor and metastasize more easily. Conclusion Taken together, we demonstrate that MLH1 deficiency, low SPTAN1 expression, and tumor progression and metastasis are in close relation. We conclude that SPTAN1 is a candidate molecule explaining the tumor progression and metastasis of MLH1-deficient CRCs. The detailed analysis of SPTAN1 is now mandatory to substantiate its relevance and its potential value as a candidate protein for targeted therapy, and as a predictive marker of cancer aggressiveness.

Membrane-proximal and truncated mutations of colony-stimulating factor 3 receptor (CSF3R) are frequently found in chronic neutrophilic leukemia (CNL) and atypical chronic myeloid leukemia (aCML). However, rearrangement involving CSF3R in hematological neoplasms has not been reported. Here, we report a case of a 21-year-old female diagnosed as aCML with t(1;9)(p34;q34) who presented a CSF3R rearrangement. First, RNA sequencing identified a novel fusion transcript involving exon 17 of CSF3R and exon 50 of non-erythrocytic-1-spectrin-alpha (SPTAN1). Subsequent reverse transcription-polymerase chain reaction (RT-PCR) and bidirectional Sanger sequencing confirmed the in-frame fusion. The breakpoint was located at the C-terminus of CSF3R, suggesting a pattern of truncation mutation of CSF3R. Unexpectedly, the patient failed to achieve a complete hematological response following the SRC kinase inhibitor dasatinib therapy, which has been reported to effectively inhibit truncated forms of CSF3R. The patient accepted allogeneic hematopoietic stem cell transplantation (HSCT) and currently remains in a good state. In conclusion, this report is the first to identify a fusion involving CSF3R and SPTAN1 in aCML with t(1;9)(p34;q34).