Interfering Expression of Chimeric Transcript SEPT7P2-PSPH Promotes Cell Proliferation in Patients with Nasopharyngeal Carcinoma

Introduction. Nasopharyngeal carcinoma (NPC) is a distinct type of head and neck cancer which is mostly prevalent in southern China. The development of NPC involves accumulation of multiple genetic changes. Chromosomal translocation is always thought to be accompanied with the fusion chimeric products. To data, the role of the fusion chimeric transcript remains obscure. Materials and Methods. We performed RNA sequencing to detect the fusion genes in ten NPC tissues. Sanger sequencing and quantitative RT-PCR were used to measure the level of the fusion chimeric transcript in NPC tissues and cell lines. The functional experiments such as CCK8 assay, colony formation, and migration/invasion were conducted to analyze the role of this transcript in NPC in vitro. Results. We demonstrated that the chimeric transcript SEPT7P2-PSPH was formed by trans-splicing of adjacent genes in the absence of chromosomal rearrangement and observed in both NPC patients and cell lines in parallel. Low-expression of the SEPT7P2-PSPH chimeric transcript induced the protein expression of PSPH and promoted cell proliferation, metastasis/invasion, and transforming ability in vitro. Conclusions. Our findings indicate that the chimeric transcript SEPT7P2-PSPH is a product of trans-splicing of two adjacent genes and might be a tumor suppressor gene, potentially having the role of anticancer activity.

Massive Parallel Sequencing and Mutations Analysis of Mismatch Repair Genes in Recurrent Childhood Acute Lymphoblastic Leukemia Cases-Identification of Possible Molecular Signature of Poor Clinical Outcome

[Introduction] Mechanism of recurrence is fully characterized and is significant to improve prognosis in childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL) and T lymphoblastic leukemia (T-ALL).. We have analyzed recurrent cases of childhood BCP-ALL and T-ALL. [Procedure] We analyzed clinical samples of 18 cases with BCP-ALL and 3 cases with T-ALL, who had been treated in our institution. We have investigated gene status of IKZF1, CRLF2, CDKN2A/2B, JAKs, IL7RA, and TP53 using RT-PCR and MLPA methods and IGH/TCR on genomic PCR. Whole exome analysis was done using Ion AmpliSeq Exome in seven cases. [Result] We analyzed clinical samples of 21 cases with ALL, who had been treated in our institution. The cases were 18 cases with BCP-ALL and 3 cases with T-ALL. We have investigated gene status of IKZF1, CRLF2, CDKN2A/2B,JAKs,IL7RA, NOTCH (for T-ALL), and TP53. Whole exome analysis was done in two cases, particularly for a case from which we have established cell line. < Result > Eight BCP-ALL cases with P2RY8-CRLF2 chimeric transcript: four cases of which had P2RY8-CRLF2 chimeric transcript only at initial diagnosis; two cases obtained transcript at recurrence. This was confirmed employing LD-PCR genomic analysis. Ten BCP-ALL cases had deletion of IKZF1; two showed deletion at relapse and a case demonstrated deletion at diagnosis only. Two BCP-ALL cases showed mutation of IL7RA. One of T-ALL cases from which we have established cell line showed mutation of MSH2 and more than 200 non-synonymous mutations on whole exome analysis. One T-ALL cases showed mutation of JAK3 at diagnosis. One BCP-ALL case had MLH1 mutation < Discussion > The present study has suggested acquisition of complex genetic change at different point of evolution may work in recurrence of ALL. The present study has indicated P2RY8-CRLF2 works not as simple growth advantage but rather as manifestation of genomic instability. This may be also illustrated by recurrent cases with T-ALL having mutation of MSH2 and BCP-ALL having mutation of MLH1. Mutation of mismatch repair gene may be driver of gene mutation acquisition and consequently alterations of CREBBP and RAS or IKZF1, TP53, mismatch repair genes, or emergence of P2RY-CRLF2 chimeric transcript may be prognostically relevant in childhood acute lymphoblastic leukemia. Disclosures No relevant conflicts of interest to declare.