Genomic and Immunologic Correlates in Prostate Cancer with High Expression of KLK2.

The identification of surfaceome proteins is a main goal in cancer research to design antibody-based therapeutic strategies. T cell engagers based on KLK2, a kallikrein specifically expressed in prostate cancer (PRAD), are currently in early clinical development. Using genomic information from different sources, we evaluated the immune microenvironment and genomic profile of prostate tumors with high expression of KLK2. KLK2 was specifically expressed in PRAD but it was not significant associated with Gleason score. Additionally, KLK2 expression did not associate with the presence of any immune cell population and T cell activating markers. A mild correlation between the high expression of KLK2 and the deletion of TMPRSS2 was identified. KLK2 expression associated with high levels of surface proteins linked with a detrimental response to immune checkpoint inhibitors (ICIs) including CHRNA2, FAM174B, OR51E2, TSPAN1, PTPRN2, and the non-surface protein TRPM4. However, no association of these genes with an outcome in PRAD was observed. Finally, the expression of these genes in PRAD did not associate with an outcome in PRAD and any immune populations. We describe the immunologic microenvironment on PRAD tumors with a high expression of KLK2, including a gene signature linked with an inert immune microenvironment, that predicts the response to ICIs in other tumor types. Strategies targeting KLK2 with T cell engagers or antibody-drug conjugates will define whether T cell mobilization or antigen release and stimulation of immune cell death are sufficient effects to induce clinical activity.

Tumor-derived KLK8 predicts inferior survival and promotes an immune-suppressive tumor microenvironment in lung squamous cell carcinoma.

Lung squamous cell carcinoma (LUSC) is the second most common lung cancer worldwide, leading to millions of deaths annually. Although immunotherapy has expanded the therapeutic choices for LUSC and achieved considerable efficacy in a subset of patients, many patients could not benefit, and resistance was pervasive. Therefore, it is significant to investigate the mechanisms leading to patients' poor response to immunotherapies and explore novel therapeutic targets. Using multiple public LUSC datasets, we found that Kallikrein-8 (KLK8) expression was higher in tumor samples and was correlated with inferior survival. Using a LUSC cohort (n = 190) from our center, we validated the bioinformatic findings about KLK8 and identified high KLK8 expression as an independent risk factor for LUSC. Function enrichment showed that several immune signaling pathways were upregulated in the KLK8 low-expression group and downregulated in the KLK8 high-expression group. For patients with low KLK8 expression, they were with a more active TME, which was both observed in the TCGA database and immune marker immunohistochemistry, and they had extensive positive relations with immune cells with tumor-eliminating functions. This study identified KLK8 as a risk factor in LUSC and illustrated the associations between KLK8 and cancer immunity, suggesting the potentiality of KLK8 as a novel immune target in LUSC.

A mechanism for hereditary angioedema caused by a methionine-379-to-lysine substitution in kininogens.

ABSTRACT: Hereditary angioedema (HAE) is associated with episodic kinin-induced swelling of the skin and mucosal membranes. Most patients with HAE have low plasma C1-inhibitor activity, leading to increased generation of the protease plasma kallikrein (PKa) and excessive release of the nanopeptide bradykinin from high-molecular-weight kininogen (HK). However, disease-causing mutations in at least 10% of patients with HAE appear to involve genes for proteins other than C1-inhibitor. A point mutation in the Kng1 gene encoding HK and low-molecular weight kininogen (LK) was identified recently in a family with HAE. The mutation changes a methionine (Met379) to lysine (Lys379) in both proteins. Met379 is adjacent to the Lys380-Arg381 cleavage site at the N-terminus of the bradykinin peptide. Recombinant wild-type (Met379) and variant (Lys379) versions of HK and LK were expressed in HEK293 cells. PKa-catalyzed kinin release from HK and LK was not affected by the Lys379 substitutions. However, kinin release from HK-Lys379 and LK-Lys379 catalyzed by the fibrinolytic protease plasmin was substantially greater than from wild-type HK-Met379 and LK-Met379. Increased kinin release was evident when fibrinolysis was induced in plasma containing HK-Lys379 or LK-Lys379 compared with plasma containing wild-type HK or LK. Mass spectrometry revealed that the kinin released from wild-type and variant kininogens by PKa is bradykinin. Plasmin also released bradykinin from wild-type kininogens but cleaved HK-Lys379 and LK-Lys379 after Lys379 rather than Lys380, releasing the decapeptide Lys-bradykinin (kallidin). The Met379Lys substitutions make HK and LK better plasmin substrates, reinforcing the relationship between fibrinolysis and kinin generation.

Kallikrein-Related Peptidase 4 Promotes Proliferation, Migration, Invasion, and Pro-Angiogenesis of Endometrial Stromal Cells via Regulation of Brain-Derived Neurotrophic Factor Production in Endometriosis.

Endometriosis is a common benign gynecologic condition. Endometriosis lesions are associated with endometrial cell proliferation, migration, invasion, and neovascularization, while the specific molecular mechanisms are still elusive. Transcriptome sequencing has been used for the identification of diagnostic markers in endometriosis. Here, transcriptome profiling revealed that kallikrein-related peptidase 4 (KLK4) expression was up-regulated in ectopic endometrium (EC) tissues of patients with endometriosis. KLK4 mediates the degradation of extracellular matrix proteins, and its proteolytic activity activates many tumorigenic and metastatic pathways via tumor invasion and migration. Nevertheless, whether KLK4 serves as an important regulatory factor in endometriosis remains unclear. This study confirmed that KLK4 was highly expressed in ectopic endometrial stromal cells (EC-ESCs). KLK4 overexpression promoted proliferation and suppressed apoptosis of EC-ESCs, induced cell migration and invasion, and enhanced angiogenesis in vivo. Mechanistically, KLK4 overexpression mediated the protein cleavage of pro-brain-derived neurotrophic factor in EC-ESCs. Finally, brain-derived neurotrophic factor was a vital downstream substrate of KLK4 maintained the proliferation, metastasis, and pro-angiogenesis abilities and inhibited apoptosis of ESCs through a rescue study. Together, these findings demonstrate the promotive role of KLK4 in endometriosis development. In addition, the study provides a new insight that KLK4 might be a potential therapeutic target and prognostic marker for patients with endometriosis.

Evaluation of HNF1B, KLK3, ELAC2, TMPRSS2-ERG, and CTNNB1 polymorphisms associated with prostate cancer in samples of patients from HUPE-UERJ.

PURPOSE: Prostate cancer (PCa) is the leading cause of death among men in 48 countries. Genetic alterations play a significant role in PCa carcinogenesis. For the hypothesis of this research, five unique polymorphisms (SNP) were investigated in different genes that showed to be associated in different ways with PCa: rs4430796, rs2735839, rs4792311, rs12329760, and rs28931588, respectively for the genes HNF1B, KLK3, ELAC2, TMPRSS2-ERG, and CTNNB1. PATIENTS AND METHODS: Blood samples from 426 subjects were evaluated: 290 controls (161 females and 129 males) and 136 PCa patients. SNP were determined by real-time polymerase chain reaction. TaqMan SNP genotyping assay. In the control samples, the SNPs were defined in association with the self-reported ethnicity, and in 218 control samples with markers with ancestry indicators. The genes were in Hardy-Weinberg equilibrium. One hundred and seventy control samples were matched by ethnicity for comparison with the PCa samples. RESULTS: The G allele at rs28931588 was monomorphic in both patients and controls studied. Significant differences were observed in allelic and genotypic frequencies between the control and Pca samples in rs2735839 (KLK3; p = 0.002 and χ2 = 8.73 and p = 0.01, respectively), by the global frequency and in the dominant model rs2735839_GG (odds ratio [OR] = 0.51, p = 0.02). AA and GA genotypes at rs4792311 (ELAC2) were more frequent in patients with Gleason 7(4 + 3), 8, and 9 (n = 37%-59.7%) compared to patients with Gleason 6 and 7(3 + 4) (n = 26%-40.0%) conferring a protective effect on the GG genotype (OR = 0.45, p = 0.02). The same genotype showed an OR = 2.71 (p = 0.01) for patients with low severity. The HNF1B-KLK3-ELAC2-TMPRSS2-ERG haplotypes: GAAT, AAAT, GAGT, and AAGT were more frequent in patients with Pca with OR ranging from 4.65 to 2.48. CONCLUSIONS: Higher frequencies of risk alleles were confirmed in the SNPs, KLK3 rs2735839_A, ELAC2 rs4792311_A, and TMPRSS2 rs12329760_T in patients with Pca. Rs2735839_A was associated with risk of Pca and rs4792311_A with severity and Gleason score of 7(4 + 3) or greater. There is a need for careful observation of rs2735839 and rs4792311 in association with the prostatic biopsy due to the increased risk of Pca.

KLK10 promotes the progression of KRAS mutant colorectal cancer via PAR1-PDK1-AKT signaling pathway.

Kirsten rat sarcoma virus (KRAS) gene mutation is common in colorectal cancer (CRC) and is often predictive of treatment failure and poor prognosis. To understand the mechanism, we compared the transcriptome of CRC patients with wild-type and mutant KRAS and found that KRAS mutation is associated with the overexpression of a secreted serine protease, kallikrein-related peptidase 10 (KLK10). Moreover, using in vitro and in vivo models, we found that KLK10 overexpression favors the rapid growth and liver metastasis of KRAS mutant CRC and can also impair the efficacy of KRAS inhibitors, leading to drug resistance and poor survival. Further functional assays revealed that the oncogenic role of KLK10 is mediated by protease-activated receptor 1 (PAR1). KLK10 cleaves and activates PAR1, which further activates 3-phosphoinositide-dependent kinase 1 (PDK1)-AKT oncogenic pathway. Notably, suppressing PAR1-PDK1-AKT cascade via KLK10 knockdown can effectively inhibit CRC progression and improve the sensitivity to KRAS inhibitor, providing a promising therapeutic strategy. Taken together, our study showed that KLK10 promotes the progression of KRAS mutant CRC via activating PAR1-PDK1-AKT signaling pathway. These findings expanded our knowledge of CRC development, especially in the setting of KRAS mutation, and also provided novel targets for clinical intervention.

Kallikrein-related peptidase 10 predicts prognosis and mediates tumor immunomodulation in colorectal cancer.

The incidence and mortality rates of colorectal cancer (CRC) have significantly increased in recent years. It has been shown that early diagnosis of CRC improves the five-year survival of patients compared to late diagnosis, as patients with stage I disease have a five-year survival rate as high as 90 %. Through bioinformatics analysis, we identified Kallikrein 10 (KLK10), a member of the Kallikrein family, as a reliable predictor of CRC progression, particularly in patients with early-stage CRC. Furthermore, single-cell analysis revealed that KLK10 was highly expressed in tumor and partial immune cells. Analysis of the biological functions of KLK10 using the Kyoto encyclopedia of genes and genomes and gene ontology indicated that KLK10 plays a role in the proliferation and differentiation of cancer cells, along with the maintenance of tumor function and immune regulation, explicitly by T cells and macrophages. EdU cell proliferation staining, plate clone formation assay, and cell scratch assay demonstrated that KLK10 inhibition by siRNA affected the proliferation and migration of CRC cells. Cell cycle detection by flow cytometry demonstrated that KLK10 inhibition led to cell cycle arrest in the G1 phase. In addition, the proportion of M1 and M2 macrophages in 45 tumor specimens was analyzed by immunohistochemistry, the proportion of CD4+ T cells and CD8+ T cells in plasma was identified by flow cytometry, and their correlation with KLK10 was analyzed. The effects of KLK10 on T cells and macrophages were verified in independent cell experiments. The results revealed that KLK10 also activates CD4+ T cells, mediating M2-type macrophage polarization.

circSSPO boosts growth of esophageal squamous cell carcinoma through upregulation of micrRNA-6820-5p-mediated KLK8 and PKD1 expression.

Investigation on a competitive endogenous RNA (ceRNA) network attracted lots of attention due its function in cancer regulation. Here, we probed into the possible molecular mechanism of circSSPO/microRNA-6820-5p (miR-6820-5p)/kallikrein-related peptidase 8 (KLK8)/PKD1 network in the esophageal squamous cell carcinoma (ESCC). Following whole-transcriptome sequencing and differential analysis in collected ESCC tissue samples, circRNA-miRNA-mRNA regulatory network affecting ESCC was investigated. After interaction measurement among circSSPO/miR-6820-5p/KLK8/PKD1, their regulatory roles in ESCC cell functions in vitro and xenograft tumor growth and lung metastasis in vivo were analyzed. The bioinformatics prediction and sequencing results screened that circSSPO, miR-6820-5p, KLK8, and PKD1 were associated with ESCC development. In ESCC, miR-6820-5p was expressed at very low levels, while circSSPO, KLK8, and PKD1 were highly expressed. In vitro cell experiments further proved that circSSPO competitively inhibited miR-6820-5p to induce ESCC cell malignant properties. Moreover, knockdown of KLK8 or PKD1 inhibited ESCC cell malignant properties. circSSPO also promoted the tumorigenic and metastasis of ESCC through the upregulation of KLK8 and PKD1 expression in vivo. We found that circSSPO was an oncogenic circRNA that was significantly abundant in ESCC tissues and circSSPO exhibited an oncogenic activity in ESCC by elevating expression of KLK8 and PKD1 through suppressing miR-6820-5p expression.

MiR-107-3p Knockdown Alleviates Endothelial Injury in Sepsis via Kallikrein-Related Peptidase 5.

INTRODUCTION: Endothelial injury is a major characteristic of sepsis and contributes to sepsis-induced multiple-organ dysfunction. In this study, we investigated the role of miR-107-3p in sepsis-induced endothelial injury. METHODS: Human umbilical vein endothelial cells (HUVECs) were exposed to 20 µg/mL of lipopolysaccharide (LPS) for 6-48 h. The levels of miR-107-3p and kallikrein-related peptidase 5 (KLK5) were examined. HUVECs were treated with LPS for 12 h and subsequently transfected with miR-107-3p inhibitor, KLK5 siRNA, or cotransfected with KLK5 siRNA and miR-107-3p inhibitor/negative control inhibitor. Cell survival, apoptosis, invasion, cell permeability, inflammatory response, and the Toll-like receptor 4/nuclear factor κB signaling were evaluated. In addition, the relationship between miR-107-3p and KLK5 expression was predicted and verified. RESULTS: LPS significantly elevated miR-107-3p levels, which peaked at 12 h. Conversely, the KLK5 level was lower in the LPS group than in the control group and was lowest at 12 h. MiR-107-3p knockdown significantly attenuated reductions in cell survival and invasion, apoptosis promotion, hyperpermeability and inflammation induction, and activation of the NF-κB signaling caused by LPS. KLK5 knockdown had the opposite effect. Additionally, KLK5 was demonstrated as a target of miR-107-3p. MiR-107-3p knockdown partially reversed the effects of KLK5 depletion in LPS-activated HUVECs. CONCLUSIONS: Our findings indicate that miR-107-3p knockdown may protect against sepsis-induced endothelial cell injury by targeting KLK5. This study identified a novel therapeutic target for sepsis-induced endothelial injury.

Retrospective pharmacogenetic study of psoriasis highlights the role of KLK7 in tumour necrosis factor signalling.

BACKGROUND: Multiple treatment options are available for the management of psoriasis, but clinical response varies among individual patients and no biomarkers are available to facilitate treatment selection for improved patient outcomes. OBJECTIVES: To utilize retrospective data to conduct a pharmacogenetic study to explore the potential genetic pathways associated with drug response in the treatment of psoriasis. METHODS: We conducted a retrospective pharmacogenetic study using self-evaluated treatment response from 1942 genotyped patients with psoriasis. We examined 6 502 658 genetic markers to model their associations with response to six treatment options using linear regression, adjusting for cohort variables and demographic features. We further utilized an integrative approach incorporating epigenomics, transcriptomics and a longitudinal clinical cohort to provide biological implications for the topmost signals associated with drug response. RESULTS: Two novel markers were revealed to be associated with treatment response: rs1991820 (P = 1.30 × 10-6) for anti-tumour necrosis factor (TNF) biologics; and rs62264137 (P = 2.94 × 10-6) for methotrexate, which was also associated with cutaneous mRNA expression levels of two known psoriasis-related genes KLK7 (P = 1.0 × 10-12) and CD200 (P = 5.4 × 10-6). We demonstrated that KLK7 expression was increased in the psoriatic epidermis, as shown by immunohistochemistry, as well as single-cell RNA sequencing, and its responsiveness to anti-TNF treatment was highlighted. By inhibiting the expression of KLK7, we further illustrated that keratinocytes have decreased proinflammatory responses to TNF. CONCLUSIONS: Our study implicates the genetic regulation of cytokine responses in predicting clinical drug response and supports the association between pharmacogenetic loci and anti-TNF response, as shown here for KLK7.

Serine protease inhibitors decrease metastasis in prostate, breast, and ovarian cancers.

Targeted therapies for prostate, breast, and ovarian cancers are based on their activity against primary tumors rather than their anti-metastatic activity. Consequently, there is an urgent need for new agents targeting the metastatic process. Emerging evidence correlates in vitro and in vivo cancer invasion and metastasis with increased activity of the proteases mesotrypsin (prostate and breast cancer) and kallikrein 6 (KLK6; ovarian cancer). Thus, mesotrypsin and KLK6 are attractive putative targets for therapeutic intervention. As potential therapeutics for advanced metastatic prostate, breast, and ovarian cancers, we report novel mesotrypsin- and KLK6-based therapies, based on our previously developed mutants of the human amyloid ß-protein precursor Kunitz protease inhibitor domain (APPI). These mutants, designated APPI-3M (prostate and breast cancer) and APPI-4M (ovarian cancer), demonstrated significant accumulation in tumors and therapeutic efficacy in orthotopic preclinical models, with the advantages of long retention times in vivo, high affinity and favorable pharmacokinetic properties. The applicability of the APPIs, as a novel therapy and for imaging purposes, is supported by their good safety profile and their controlled and scalable manufacturability in bioreactors.

Prognostic impact of kallikrein-related peptidase transcript levels in prostate cancer.

We aimed to study mRNA levels and prognostic impact of all 15 human kallikrein-related peptidases (KLKs) and their targets, proteinase-activated receptors (PARs), in surgically treated prostate cancer (PCa). Seventy-nine patients with localized grade group 2-4 PCas represented aggressive cases, based on metastatic progression during median follow-up of 11 years. Eighty-six patients with similar baseline characteristics, but no metastasis during follow-up, were assigned as controls. Transcript counts were detected with nCounter technology. KLK12 protein expression was investigated with immunohistochemistry. The effects of KLK12 and KLK15 were studied in LNCaP cells using RNA interference. KLK3, -2, -4, -11, -15, -10 and -12 mRNA, in decreasing order, were expressed over limit of detection (LOD). The expression of KLK2, -3, -4 and -15 was decreased and KLK12 increased in aggressive cancers, compared to controls (P < .05). Low KLK2, -3 and -15 expression was associated with short metastasis-free survival (P < .05) in Kaplan-Meier analysis. PAR1 and -2 were expressed over LOD, and PAR1 expression was higher, and PAR2 lower, in aggressive cases than controls. Together, KLKs and PARs improved classification of metastatic and lethal disease over grade, pathological stage and prostate-specific antigen combined, in random forest analyses. Strong KLK12 immunohistochemical staining was associated with short metastasis-free and PCa-specific survival in Kaplan-Meier analysis (P < .05). Knock-down of KLK15 reduced colony formation of LNCaP cells grown on Matrigel basement membrane preparation. These results support the involvement of several KLKs in PCa progression, highlighting, that they may serve as prognostic PCa biomarkers.

Kallikrein-Related Peptidase 12 (KLK12) in Breast Cancer as a Favorable Prognostic Marker.

Kallikrein-related peptides (KLKs) form an evolutionally conserved subgroup of secreted serine proteases that consists of 15 members (KLK1-15). Previous studies have shown that KLKs regulate diverse biological processes, but the clinical significance of KLKs remains largely unclear in human breast cancers. We examined the expression profile of 15 KLK genes in breast carcinomas using microarray data. Next, we immunolocalized KLK12 in 140 breast carcinomas and evaluated its clinical significance. Subsequently, we examined the effects of KLK12 on proliferation and migration in breast cancer cell lines. From microarray analyses, it turned out that KLK12 was the most strongly associated with low-grade malignancy in breast carcinomas among the 15 KLK members. Immunohistochemical KLK12 status was positively associated with ER and PR status, while it was inversely associated with stage, pathological T factor, lymph node metastasis, and distant metastasis. Prognostic analyses demonstrated that KLK12 was a favorable prognostic factor for both disease-free and breast cancer-specific survival of the patients. Furthermore, the knockdown of KLK12 significantly increased cell proliferation activity and cell migration of breast cancer cells. These results suggest that KLK12 has antitumorigenic effects associated with proliferation and migration and immunohistochemical KLK12 status as a potent favorable prognostic factor in breast carcinoma patients.

Targeted and explorative profiling of kallikrein proteases and global proteome biology of pancreatic ductal adenocarcinoma, chronic pancreatitis, and normal pancreas highlights disease-specific proteome remodelling.

Pancreatic ductal adenocarcinoma (PDAC) represents one of the most aggressive and lethal malignancies worldwide with an urgent need for new diagnostic and therapeutic strategies. One major risk factor for PDAC is the pre-indication of chronic pancreatitis (CP), which represents highly inflammatory pancreatic tissue. Kallikreins (KLKs) are secreted serine proteases that play an important role in various cancers as components of the tumor microenvironment. Previous studies of KLKs in solid tumors largely relied on either transcriptomics or immunodetection. We present one of the first targeted mass spectrometry profiling of kallikrein proteases in PDAC, CP, and normal pancreas. We show that KLK6 and KLK10 are significantly upregulated in PDAC (n=14) but not in CP (n=7) when compared to normal pancreas (n=16), highlighting their specific intertwining with malignancy. Additional explorative proteome profiling identified 5936 proteins in our pancreatic cohort and observed disease-specific proteome rearrangements in PDAC and CP. As such, PDAC features an enriched proteome motif for extracellular matrix (ECM) and cell adhesion while there is depletion of mitochondrial energy metabolism proteins, reminiscent of the Warburg effect. Although often regarded as a PDAC hallmark, the ECM fingerprint was also observed in CP, alongside with a prototypical inflammatory proteome motif as well as with an increased wound healing process and proteolytic activity, thereby possibly illustrating tissue autolysis. Proteogenomic analysis based on publicly accessible data sources identified 112 PDAC-specific and 32 CP-specific single amino acid variants, which among others affect KRAS and ANKHD1. Our study emphasizes the diagnostic potential of kallikreins and provides novel insights into proteomic characteristics of PDAC and CP.

Behavior of the renal kallikrein in spontaneously hypertensive rats: Influence of sexual hormones and aldosterone-sensitive distal nephron ion channels.

The renal kallikrein-kinin system (RKKS) has been related to blood pressure control and sodium and water balance. We have previously shown that female spontaneously hypertensive rats (SHR) have high urinary kallikrein activity (UKa) and lower blood pressure (BP) than males whereas ovariectomy stimulates UKa and diminishes BP. We also showed that high K+ intake and prepuberal gonadectomy (Gx) diminish BP with a concomitant increase in UKa and plasma aldosterone levels. Since kallikrein co-localize in the same distal nephron segments of aldosterone effectors, we explored the effect of pharmacological blockage of aldosterone receptor, epithelial Na+ (ENaC) and the rectifying outer medulla K+ (ROMK) channels in different gonad contexts on the gene expression, renal tissue content and urine release of kallikrein. Klk1 gene expression was determined by real-time PCR and enzymatic activity of kallikrein by the amidolytic method. We found that the inhibition of the aldosterone receptor by spironolactone increases kallikrein renal tissue storage and decreases its urinary activity, especially in Gx rats. Moreover, ENaC blockade by benzamil increases the renal content of kallikrein without affecting synthesis or excretion, especially in females and Gx animals, while the inhibition of ROMK by glibenclamide increases the synthesis and renal content of kallikrein only in intact male animals. We concluded that RKKS regulation showed sexual dimorphism and seemed to be modulated by sex hormones throughout a process involving aldosterone and the aldosterone-sensitive ion channels..

KLK6 Functions as an Oncogene and Unfavorable Prognostic Factor in Bladder Urothelial Carcinoma.

Background: Kallikrein-related peptidase 6 (KLK6) has been substantiated as a diagnostic, prognostic, and therapeutic molecular in several cancer types. In our study, we attempt to explore the biological functions of KLK6 in bladder urothelial carcinoma (BLCA). Methods: KLK6 gene expression prognostic, gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), gene set enrichment analysis (GSEA), and immune infiltration were analyzed using The Cancer Genome Atlas (TCGA) database. In vitro and in vivo experimental measurements, including CCK8, transwell migration, TUNEL, and nude mouse transplanted tumor model, were used to evaluate the antineoplastic activities of KLK6 loss-of-function. Results: The combination of bioinformatics analyses and experimental measurements demonstrate that KLK6 expression is aberrantly upregulated in human specimens and cell lines of BLCA. GO and GSEA enrichment analyses exhibited that KLK6 is implicated in the inflammatory response and immune infiltration, suggesting that upregulation of KLK6 may be associated with the progression of BLCA. Knockdown of KLK6 is able to inhibit the growth and migration and trigger apoptosis of RT4 and T24 cells. Moreover, the TCGA database indicates that KLK6 high expression in BLCA patients showed a poorer prognosis than those patients with KLK6 low expression. Univariate and multivariate regression analyses suggest KLK6 as an independent prognostic factor to predict unfavorable OS in patients with BLCA. Conclusion: KLK6 is an independent prognostic factor and an antitumor target of BLCA. KLK6 expression positively correlates with several immune cells infiltration, indicating that inhibition of KLK6 may contribute to immunotherapy of BLCA.

Vaspin Alleviates Sepsis-Induced Cardiac Injury and Cardiac Inflammation by Inhibiting Kallikrein 7 in Mice.

Background: Vaspin is an important adipokine that is involved in cardiovascular diseases. This study is aimed at investigating whether vaspin participates in sepsis-induced cardiac injury and explored the possible mechanism. Methods: First, cecal ligation and puncture (CLP) and lipopolysaccharide (LPS) were used to establish a mouse model of sepsis, and cardiac vaspin expression was examined. In addition, after pretreatment with vaspin or phosphate-buffered saline (PBS), wild-type (WT) mice underwent CLP to establish a septic model and received sham as a control. Finally, WT mice and kallikrein 7 (KLK7-/-) mice were underwent CLP with or without vaspin pretreatment. Results: Mice that underwent CLP and were administered LPS exhibited increased vaspin expression in both the heart and serum compared with sham- or saline-treated mice. In CLP mice, pretreatment with vaspin reduced mortality and alleviated the expression of cardiac injury markers and cardiac dysfunction. In addition, vaspin reduced the cardiac levels of CD45+ cells and CD68+ cells, alleviated the cardiac inflammatory response, and reduced cardiomyocyte apoptosis. The protective effects of vaspin on CLP mice were masked by the deletion of KLK7, which was demonstrated to be a downstream signal of vaspin. Conclusions: Vaspin alleviates cardiac inflammation and plays a protective role in sepsis-induced cardiac injury by reducing KLK7 expression.

Correlation analysis between CD133, Klk3 and grhl2 expression and tumor characteristics in prostate cancer.

Prostate cancer is a common clinical disease in men. It is known that prostate cancer ranks 3rd in the incidence of malignant tumors of the male genitourinary system in China, which is able to evaluate the riskiness of life expectancy of male patients. Therefore, we investigated the expression of CD133, recombinant human kallikrein 3 (Klk3), grainy head like 2 (grhl2) in prostate cancer, and correlation with tumor characteristics in the present study. A total of 167 prostate cancer patients who underwent surgical treatment in our hospital from February 2017 to April 2021 were selected. Their cancer and adjacent tissues were resected, and CD133 was detected by double staining using immunohistochemistry, Klk3 and grhl2 were detected by RT-PCR analysis, and CD133, Klk3 were analyzed by Pearson's method in different clinical stages, Gleason grade Correlation of grhl2 with tumor characteristics. The expression of CD133, KLK3, and GRHL2 in cancer tissue was increased compared with adjacent tissue (P < 0.05). The expression of CD133, KLK3, and GRHL2 increased with the aggravation of the clinical stage and Gleason grade (P < 0.05). CD133, KLK3, and GRHL2 showed a positive correlation in prostate cancer. The Pearson method found a positive correlation between CD133, KLK3, GRHL2 and clinical stage, Gleason grade, and lymph node metastasis. In general, high CD133, Klk3, and grhl2 expression was observed in prostate cancer and increased with the disease. They presented a positive correlation in prostate cancer presence, and these three gene products correlated with tumor characteristics.

Kallikrein-Related Peptidase 6 (KLK6) as a Contributor toward an Aggressive Cancer Cell Phenotype: A Potential Role in Colon Cancer Peritoneal Metastasis.

Kallikrein-related peptidases (KLKs) are implicated in many cancer-related processes. KLK6, one of the 15 KLK family members, is a promising biomarker for diagnosis of many cancers and has been associated with poor prognosis of colorectal cancer (CRC) patients. Herein, we evaluated the expression and cellular functions of KLK6 in colon cancer-derived cell lines and in clinical samples from CRC patients. We showed that, although many KLKs transcripts are upregulated in colon cancer-derived cell lines, KLK6, KLK10, and KLK11 are the most highly secreted proteins. KLK6 induced calcium flux in HT29 cells by activation and internalization of protease-activated receptor 2 (PAR2). Furthermore, KLK6 induced extracellular signal-regulated kinases 1 and 2 (ERK1/2) phosphorylation. KLK6 suppression in HCT-116 colon cancer cells decreased the colony formation, increased cell adhesion to extracellular matrix proteins, and reduced spheroid formation and compaction. Immunohistochemistry (IHC) analysis demonstrated ectopic expression of KLK6 in human colon adenocarcinomas but not in normal epithelia. Importantly, high levels of KLK6 protein were detected in the ascites of CRC patients with peritoneal metastasis, but not in benign ascites. These data indicate that KLK6 overexpression is associated with aggressive CRC, and may be applied to differentiate between benign and malignant ascites.