Elevated SPINK2 gene expression is a predictor of poor prognosis in acute myeloid leukemia

Temporary serine protease inhibition and the role of SPINK2 in human bone marrow

Protease temporary inhibitors are true substrates that bind the catalytic site with high affinity but are slowly degraded, thus acting as inhibitor for a defined time window. Serine peptidase inhibitor Kazal type (SPINK) family is endowed with such functional property whose physiological meaning is poorly explored. High expression of SPINK2 in some hematopoietic malignancies prompted us to investigate its role in adult human bone marrow. We report here the physiological expression of SPINK2 in hematopoietic stem and progenitor cells (HSPCs) and mobilized cluster differentiation 34 (CD34)⁺ cells. We determined the SPINK2 degradation constant and derived a mathematical relationship predicting the zone of inhibited target protease activity surrounding the SPINK2-secreting HSPCs. Analysis of putative target proteases for SPINK2 revealed the expression of PRSS2 and PRSS57 in HSPCs. Our combined results suggest that SPINK2 and its target serine proteases might play a role in the intercellular communication within the hematopoietic stem cell niche.

Upregulation of SPINK2 in acute myeloid leukemia

Objectives

Acute myeloid leukemia (AML) is a highly heterogeneous disease. Although patients can be classified into risk groups based on their genetic changes, the prognosis of disease within these categories varies widely. This situation raises the need to search for new molecular markers related to AML. Serine peptidase inhibitor Kazal type 2 (SPINK2) has recently been reported to be upregulated in AML and associated with poor outcomes by meta-analysis and in a limited number of AML patients.

Methods

We analyzed SPINK2 mRNA expression in 62 patients (45 adult and 17 pediatric) with AML and 11 cell lines using quantitative Real-Time PCR (qRT-PCR). SPINK2 protein level was determined using ELISA in cell lines.

Results

We found that the expression of SPINK2 mRNA and protein levels in AML cell lines (HL60 and NB4) have increased compared to other cell lines (K562, Jurkat and NALM6, MCF7, HeLa, HUVEC, hFOB, 293T, U87). SPINK2 mRNA expression was upregulated in patients with AML compared to controls (p=0.004) and significantly lower in t(8;21)-positive patients compared to negative patients (p=0.0006).

Conclusions

Our results suggest that SPINK2 serves an important role in AML development. Further studies are needed to evaluate SPINK2 expression in AML patients with t(8.21) and investigate to clarify its prognostic value in various subgroups of AML.

Investigation of distinct gene expression profile patterns that can improve the classification of intermediate-risk prognosis in AML patients

Background: Acute myeloid leukemia (AML) is a heterogeneous type of blood cancer that generally affects the elderly. AML patients are categorized with favorable-, intermediate-, and adverse-risks based on an individual's genomic features and chromosomal abnormalities. Despite the risk stratification, the progression and outcome of the disease remain highly variable. To facilitate and improve the risk stratification of AML patients, the study focused on gene expression profiling of AML patients within various risk categories. Therefore, the study aims to establish gene signatures that can predict the prognosis of AML patients and find correlations in gene expression profile patterns that are associated with risk groups. Methods: Microarray data were obtained from Gene Expression Omnibus (GSE6891). The patients were stratified into four subgroups based on risk and overall survival. Limma was applied to screen for differentially expressed genes (DEGs) between short survival (SS) and long survival (LS). DEGs strongly related to general survival were discovered using Cox regression and LASSO analysis. To assess the model's accuracy, Kaplan-Meier (K-M) and receiver operating characteristic (ROC) were used. A one-way ANOVA was performed to assess for differences in the mean gene expression profiles of the identified prognostic genes between the risk subcategories and survival. GO and KEGG enrichment analyses were performed on DEGs. Results: A total of 87 DEGs were identified between SS and LS groups. The Cox regression model selected nine genes CD109, CPNE3, DDIT4, INPP4B, LSP1, CPNE8, PLXNC1, SLC40A1, and SPINK2 that are associated with AML survival. K-M illustrated that the high expression of the nine-prognostic genes is associated with poor prognosis in AML. ROC further provided high diagnostic efficacy of the prognostic genes. ANOVA also validated the difference in gene expression profiles of the nine genes between the survival groups, and highlighted four prognostic genes to provide novel insight into risk subcategories poor and intermediate-poor, as well as good and intermediate-good that displayed similar expression patterns. Conclusion: Prognostic genes can provide more accurate risk stratification in AML. CD109, CPNE3, DDIT4, and INPP4B provided novel targets for better intermediate-risk stratification. This could enhance treatment strategies for this group, which constitutes the majority of adult AML patients.

SPINKs in Tumors: Potential Therapeutic Targets

The serine protease inhibitor Kazal type (SPINK) family includes SPINK1-14 and is the largest branch in the serine protease inhibitor family. SPINKs play an important role in pancreatic physiology and disease, sperm maturation and capacitation, Nager syndrome, inflammation and the skin barrier. Evidence shows that the unregulated expression of SPINK1, 2, 4, 5, 6, 7, and 13 is closely related to human tumors. Different SPINKs exhibit various regulatory modes in different tumors and can be used as tumor prognostic markers. This article reviews the role of SPINK1, 2, 4, 5, 6, 7, and 13 in different human cancer processes and helps to identify new cancer treatment targets.

SPINK2 is a prognostic biomarker related to immune infiltration in acute myeloid leukemia

BACKGROUND

Serine peptidase inhibitor Kazal type 2 (SPINK2) has been reported to be involved in certain cancers. We conducted an in-depth investigation on the role and mechanism of SPINK2 in acute myeloid leukemia (AML).

METHODS

The relationship between SPINK2 expression and AML clinicopathologic characteristics was determined using The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) database. Concomitantly, we used Kaplan-Meier survival analysis, as well as univariate and multivariate regression analyses to evaluate SPINK2 as a prognostic marker of AML. Additionally, we annotated the enrichment and function of SPINK2 using Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Sets Enrichment Analysis (GSEA). The CIBERSORT algorithm was used to analyze the relationship between SPINK2 expression and immune infiltration.

RESULTS

SPINK2 expression was significantly higher in AML patients compared to healthy individuals (P<0.001). The area under receiver operating characteristic curve in the GSE9476 dataset was 0.660, whereas that in the Genotype-Tissue Expression (GTEx) and TCGA datasets was 0.935. In addition, GSEA also showed that several pathways were enriched in the group with high SPINK2 expression, such as PI3K-AKT signaling, PD-L1 expression, and checkpoint pathways. Analysis of immune infiltration showed that SPINK2 expression was correlated with certain immune infiltrating cells. Cox multivariate analysis revealed that the level of SPINK2 was an independent risk factor for the progression of AML (P<0.001). Moreover, age, M1, M5, M6, and CytoRisk-Poor also affected the progression of AML (P<0.05). The C-index of the nomogram in our internal validation was 0.702.

CONCLUSION

The high expression of SPINK2 in AML suggests that SPINK2 may play an important role in the immune microenvironment and thus could be a biomarker for diagnosis and prognosis of AML.

Prognostic and clinicopathological insights of phosphodiesterase 9A gene as novel biomarker in human colorectal cancer

BACKGROUND

PDE9A (Phosphodiesterase 9A) plays an important role in proliferation of cells, their differentiation and apoptosis via intracellular cGMP (cyclic guanosine monophosphate) signaling. The expression pattern of PDE9A is associated with diverse tumors and carcinomas. Therefore, PDE9A could be a prospective candidate as a therapeutic target in different types of carcinoma. The study presented here was designed to carry out the prognostic value as a biomarker of PDE9A in Colorectal cancer (CRC). The present study integrated several cancer databases with in-silico techniques to evaluate the cancer prognosis of CRC.

RESULTS

The analyses suggested that the expression of PDE9A was significantly down-regulated in CRC tissues than in normal tissues. Moreover, methylation in the DNA promoter region might also manipulate PDE9A gene expression. The Kaplan-Meier curves indicated that high level of expression of PDE9A gene was associated to higher survival in OS, RFS, and DSS in CRC patients. PDE9A demonstrated the highest positive correlation for rectal cancer recurrence with a marker gene CEACAM7. Furtheremore, PDE9A shared consolidated pathways with MAPK14 to induce survival autophagy in CRC cells and showed interaction with GUCY1A2 to drive CRPC.

CONCLUSIONS

Overall, the prognostic value of PDE9A gene could be used as a potential tumor biomarker for CRC.

NUP-98 Rearrangements Led to the Identification of Candidate Biomarkers for Primary Induction Failure in Pediatric Acute Myeloid Leukemia

Conventional chemotherapy for acute myeloid leukemia regimens generally encompass an intensive induction phase, in order to achieve a morphological remission in terms of bone marrow blasts (<5%). The majority of cases are classified as Primary Induction Response (PIR); unfortunately, 15% of children do not achieve remission and are defined Primary Induction Failure (PIF). This study aims to characterize the gene expression profile of PIF in children with Acute Myeloid Leukemia (AML), in order to detect molecular pathways dysfunctions and identify potential biomarkers. Given that NUP98-rearrangements are enriched in PIF-AML patients, we investigated the association of NUP98-driven genes in primary chemoresistance. Therefore, 85 expression arrays, deposited on GEO database, and 358 RNAseq AML samples, from TARGET program, were analyzed for “Differentially Expressed Genes” (DEGs) between NUP98+ and NUP98-, identifying 110 highly confident NUP98/PIF-associated DEGs. We confirmed, by qRT-PCR, the overexpression of nine DEGs, selected on the bases of the diagnostic accuracy, in a local cohort of PIF patients: SPINK2, TMA7, SPCS2, CDCP1, CAPZA1, FGFR1OP2, MAN1A2, NT5C3A and SRP54. In conclusion, the integrated analysis of NUP98 mutational analysis and transcriptome profiles allowed the identification of novel putative biomarkers for the prediction of PIF in AML.

Distinct clinical and biological characteristics of acute myeloid leukemia with higher expression of long noncoding RNA KIAA0125

Expression of long non-coding RNA KIAA0125 has been incorporated in various gene expression signatures for prognostic prediction in acute myeloid leukemia (AML) patients, yet its functions and clinical significance remain unclear. This study aimed to investigate the clinical and biological characteristics of AML bearing different levels of KIAA0125. We profiled KIAA0125 expression levels in bone marrow cells from 347 de novo AML patients and found higher KIAA0125 expression was closely associated with RUNX1 mutation, but inversely correlated with t(8;21) and t(15;17) karyotypes. Among the 227 patients who received standard chemotherapy, those with higher KIAA0125 expression had a lower complete remission rate, shorter overall survival (OS) and disease-free survival (DFS) than those with lower expression. The prognostic significance was validated in both TCGA and GSE12417 cohorts. Subgroup analyses showed that higher KIAA0125 expression also predicted shorter DFS and OS in patients with normal karyotype or non-M3 AML. In multivariable analysis, higher KIAA0125 expression remained an adverse risk factor independent of age, WBC counts, karyotypes, and mutation patterns. Bioinformatics analyses revealed that higher KIAA0125 expression was associated with hematopoietic and leukemic stem cell signatures and ATP-binding cassette transporters, two predisposing factors for chemoresistance.