Human kallikrein-related peptidase 12 (KLK12) splice variants discriminate benign from cancerous breast tumors

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.

KLK12 Regulates MMP-1 and MMP-9 via Bradykinin Receptors: Biomarkers for Differentiating Latent and Active Bovine Tuberculosis

It has been established that kallikrein12 (KLK12) expression is closely related to bovine tuberculosis (bTB) development. Herein, we sought to clarify the regulatory mechanism of KLK12 and its application in tuberculosis diagnosis. KLK12 knockdown macrophages were produced by siRNA transfection. Bradykinin receptors (BR, including B1R and B2R) were blocked with specific inhibitors. Mannose-capped lipoarabinomannan (ManLAM) was extracted from Mycobacterium bovis (M. bovis) and used to study the mechanism of KLK12 activation. In addition, we constructed different mouse models representing the latent and active stages of M. bovis infection. Mouse models and clinical serum samples were used to assess the diagnostic value of biomarkers. Through the above methods, we confirmed that KLK12 regulates MMP-1 and MMP-9 via BR. KLK12 upregulation is mediated by the M. bovis-specific antigen ManLAM. KLK12, MMP-1, and MMP-9 harbor significant value as serological markers for differentiating between latent and active bTB, especially KLK12. In conclusion, we identified a novel signaling pathway, KLK12/BR/ERK/MMPs, in M. bovis-infected macrophages, which is activated by ManLAM. From this signaling pathway, KLK12 can be used as a serological marker to differentiate between latent and active bTB. Importantly, KLK12 also has enormous potential for the clinical diagnosis of human tuberculosis (TB).

The evolution and ecology of benign tumors

Tumors are usually classified into two main categories - benign or malignant, with much more attention being devoted to the second category given that they are usually associated with more severe health issues (i.e., metastatic cancers). Here, we argue that the mechanistic distinction between benign and malignant tumors has narrowed our understanding of neoplastic processes. This review provides the first comprehensive discussion of benign tumors in the context of their evolution and ecology as well as interactions with their hosts. We compare the genetic and epigenetic profiles, cellular activities, and the involvement of viruses in benign and malignant tumors. We also address the impact of intra-tumoral cell composition and its relationship with the tumoral microenvironment. Lastly, we explore the differences in the distribution of benign and malignant neoplasia across the tree of life and provide examples on how benign tumors can also affect individual fitness and consequently the evolutionary trajectories of populations and species. Overall, our goal is to bring attention to the non-cancerous manifestations of tumors, at different scales, and to stimulate research on the evolutionary ecology of host-tumor interactions on a broader scale. Ultimately, we suggest that a better appreciation of the differences and similarities between benign and malignant tumors is fundamental to our understanding of malignancy both at mechanistic and evolutionary levels.

LACTB and LC3 could serve as potential biomarkers of gastric cancer to neoadjuvant chemotherapy with oxaliplatin plus S-1

The present study investigated and evaluated the correlation between the expression of LACTB and LC3 and the clinical outcomes of patients with advanced gastric cancer treated with oxaliplatin plus S-1 neoadjuvant chemotherapy (NACT). A total of 51 patients with advanced gastric cancer underwent NACT treatment between June 2015 and June 2017. Pathomorphological changes in gastric cancer were analyzed by H&E staining. The expression level and subcellular localization of LACTB and LC3 in paraffin-embedded biopsies were detected by immunohistochemistry and immunofluorescence. The mRNA and protein expression of LACTB were investigated by reverse transcription quantitative polymerase chain reaction and Western blotting, respectively. Statistical analysis was performed to determine the association between the expression of LACTB and LC3 and clinical chemotherapy efficacy of NACT for gastric cancer. Among the 51 patients, 3 (5.88%), 27 (52.94%), 13 (25.49%) and 8 (15.69%) displayed complete remission, partial remission, stable disease and progressive disease, respectively. The rate of decreased LACTB expression was 68.6%, while the rate of increased LC3 expression was 60.8%. Furthermore, there was a significant negative correlation between the expression of LACTB and that of LC3 following NACT (P<0.001). High expression of LC3 (P<0.01) and low expression of LACTB (P<0.01) were associated with a poor response of patients with advanced gastric cancer to NACT. In conclusion, the expression of LACTB and LC3 may serve as a promising novel biomarker for determining the prognosis of patients with advanced gastric cancer receiving NACT, while its potential clinical significance requires further elucidation.

Prognostic value of kallikrein-related peptidase 12 (KLK12) mRNA expression in triple-negative breast cancer patients

BACKGROUND

The serine protease KLK12 belongs to the human fifteen-member family of kallikrein-related peptidases. Differential expression accompanied by either increased or decreased enzymatic activity has been linked to several diseases including cancer. Triple-negative breast cancer (TNBC) represents a very aggressive subgroup of breast cancer with high tumor recurrence rates and poor patient prognosis. Here, we quantified the KLK12 mRNA expression levels in tumor tissue of TNBC patients and analyzed their prognostic value.

METHODS

In the present study, KLK12 mRNA expression in tumor tissue of TNBC patients (n = 116) was determined by quantitative real-time PCR assay. The association of KLK12 mRNA levels with clinical parameters, and patients' outcome was analyzed using Chi-square tests, Cox regression models and Kaplan-Meier survival analysis.

RESULTS

Positive, but low KLK12 mRNA levels were detected in about half of the cases (54 out of 116; 47%), the other samples were negative for KLK12 mRNA expression. No significant association was observed between KLK12 mRNA levels and clinicopathological variables (age, lymph node status, tumor size, and histological grade). In univariate Cox analyses, positive KLK12 mRNA expression was significantly associated with shortened disease-free survival (DFS; hazard ratio [HR] = 2.12, 95% CI = 1.19-3.78, p = 0.010) as well as overall survival (OS; HR = 1.91, 95% CI = 1.04-3.50, p = 0.037). In multivariable Cox analysis, including all clinical parameters plus KLK12 mRNA, the latter - together with age - remained an independent unfavorable predictive marker for DFS (HR = 2.33, 95% CI = 1.28-4.24, p = 0.006) and showed a trend towards significance in case of OS (HR = 1.80, 95% CI = 0.96-3.38, p = 0.066).

CONCLUSIONS

Positive KLK12 expression is remarkably associated with shortened DFS and OS, suggesting that KLK12 plays a tumor-supporting role in TNBC.

Silencing KLK12 expression via RGDfC-decorated selenium nanoparticles for the treatment of colorectal cancer in vitro and in vivo

Short interfering RNA (siRNA) has been investigated as a promising modality of cancer treatment due to its capability to target specific target genes for downregulation. However, the successful application of this strategy depends on producing a safe and effective carrier system for delivering siRNA to the tumor. Thus, investigation of siRNA delivery carriers is a fundamental step in the field of siRNA-based therapeutics. In the current research, the surface of selenium nanoparticles (SeNPs) were modified with the tumor-targeted molecular RGDfC peptide with positive charge to synthetize the biocompatible siRNA carrier RGDfC-SeNPs. Subsequently, KLK12-siRNA was loaded onto the surface of RGDfC-SeNPs to create functionalized nanoparticles (RGDfC-Se@siRNA) that we tested for in vitro and in vivo antitumor efficacy. We measured significantly greater particle uptake in HT-29 colorectal cancer cells relative to HUVECs, providing evidence for the targeted delivery of RGDfC-Se@siRNA. We found that RGDfC-Se@siRNA could enter HT-29 cells primarily via clathrin-mediated endocytosis. Further, these particles experienced faster siRNA release in an acidic microenvironment compared to pH 7.4. The results from quantitative PCR and Western blot assays suggested that the target gene of KLK12 in HT-29 cells were obviously silenced by RGDfC-Se@siRNA. The further biological studies showed that treatment with RGDfC-Se@siRNA had ability to suppress the proliferation and migration/invasion of HT-29 cells, and triggered HT-29 cells apoptosis. RGDfC-Se@siRNA could induce the mitochondrial membrane potential (MMP) disruption and enhance the reactive oxygen species (ROS) generation in HT-29 cells, indicating that RGDfC-Se@siRNA induced the HT-29 cells apoptosis possibly by a ROS-mediated mitochondrial dysfunction pathway. Importantly, the in vivo antitumor study also verified that RGDfC-Se@siRNA could significantly suppress the growth of tumor in vivo. In addition, we did not observe any signs of systemic or tissue-specific toxicity after administration of RGDfC-Se@siRNA in mice. As a whole, these findings suggest that RGDfC-Se@siRNA has promising potential as a therapy for colorectal cancer.

Knockdown of KLK12 inhibits viability and induces apoptosis in human colorectal cancer HT-29 cell line

Kallikrein-related peptidase 12 (KLK12) is overexpressed in cancer tissues including gastric, breast and prostate cancer. However, the role of KLK12 in colorectal cancer is not fully understood. In the present study, the level of KLK12 was determined by performing reverse transcription-polymerase chain reaction (RT-qPCR) in colorectal cancer tissues and cell lines. Lipofectamine^® 2000 was used to transfect HT-29 cells to overexpress and knockdown KLK12. Cell viability, migration, invasion and apoptosis were detected by MTT, wound healing, Transwell and flow cytometry assays, respectively. The mRNA and protein expression levels of EMT-associated proteins, apoptosis-associated proteins, phosphorylated adenosine monophosphate-activated protein kinase (p-AMPK) and phosphorylated mammalian target of rapamycin (p-mTOR) were determined by RT-qPCR and western blot analysis. It was identified that the KLK12 mRNA levels were increased significantly in colorectal cancer tissues and cell lines. KLK12 small interfering RNA inhibited cell viability, migration and invasion. Furthermore, epithelial-mesenchymal transition (EMT)-associated proteins were altered by siKLK12. Cell apoptosis was induced by KLK12 downregulation, which was demonstrated by the changes in apoptosis-associated proteins; however, KLK12 overexpression produced the opposite effect. SiKLK12 enhanced the expression of p-AMPK and suppressed the expression of p-mTOR, while KLK12 overexpression had the opposite effect. Promotion of KLK12 overexpression-induced cell viability was reversed by 5-aminoimidazole-4-carboxamide ribonucleotide, an activator of the AMPK signaling pathway, and rapamycin, a specific inhibitor of the mTOR signaling pathway. Taken together, the results of the present study indicated that KLK12 was overexpressed in colorectal cancer and may regulate cell behavior, potentially via the AMPK and mTOR pathways.

CASC15 contributes to proliferation and invasion through regulating miR-766-5p/ KLK12 axis in lung cancer

Long non-coding RNAs (lncRNAs) are key mediators of cancer. The dysregulation of a lncRNA, CASC15, has been linked to several cancers, except lung cancer. Here, the aim of the study was to explore the role and mechanism of CASC15 in lung cancer regulation, with the focus on its interaction with a potential target, microRNA-766-5p (miR-766-5p) and an oncogene, kallikrein-related peptidase 12 (KLK12). Quantitative real-time PCR (qRT-PCR) was used to assess levels of CASC15, miR-766-5p and KLK12 in lung cancer tissues or cells. Western blot analysis was used to detect KLK12 protein expression. Ectopic expression of CASC15 was induced by a lentiviral system. CCK-8 and transwell assays were used to evaluate lung cancer cell proliferation and invasion, respectively. The interaction among CASC15, miR-766-5p and KLK12 was investigated by bioinformatical analysis and luciferase assay. In lung cancer tissue and cells, CASC15 was upregulated, while miR-766-5p was downregulated. Overexpression of CASC15 promoted lung cancer cell proliferation and invasion. A negative correlation was found between CASC15 and miR-766-5p levels. Overexpression of miR-766-6p reversed the cancer-promoting role of CASC15 in lung cancer cells, which was mediated by KLK12. The tumor-promoting role of CASC15 and tumor-suppressing role of miR-766-5p were also validated in vivo in tumor bearing mice, and KLK12 was also shown as an important mediator. CASC15 promotes lung cancer through the miR-766-5p/KLK12 axis, indicating that CASC15 is a potential therapeutic in lung cancer.

Kallikrein 12 Regulates Innate Resistance of Murine Macrophages against Mycobacterium bovis Infection by Modulating Autophagy and Apoptosis

Mycobacterium bovis (M. bovis) is a member of the Mycobacterium tuberculosis (Mtb) complex causing bovine tuberculosis (TB) and imposing a high zoonotic threat to human health. Kallikreins (KLKs) belong to a subgroup of secreted serine proteases. As their role is established in various physiological and pathological processes, it is likely that KLKs expression may mediate a host immune response against the M. bovis infection. In the current study, we report in vivo and in vitro upregulation of KLK12 in the M. bovis infection. To define the role of KLK12 in immune response regulation of murine macrophages, we produced KLK12 knockdown bone marrow derived macrophages (BMDMs) by using siRNA transfection. Interestingly, the knockdown of KLK12 resulted in a significant downregulation of autophagy and apoptosis in M. bovis infected BMDMs. Furthermore, we demonstrated that this KLK12 mediated regulation of autophagy and apoptosis involves mTOR/AMPK/TSC2 and BAX/Bcl-2/Cytochrome c/Caspase 3 pathways, respectively. Similarly, inflammatory cytokines IL-1β, IL-6, IL-12 and TNF-α were significantly downregulated in KLK12 knockdown macrophages but the difference in IL-10 and IFN-β expression was non-significant. Taken together, these findings suggest that upregulation of KLK12 in M. bovis infected murine macrophages plays a substantial role in the protective immune response regulation by modulating autophagy, apoptosis and pro-inflammatory pathways. To our knowledge, this is the first report on expression and the role of KLK12 in the M. bovis infection and the data may contribute to a new paradigm for diagnosis and treatment of bovine TB.

MicroRNA-3162-5p-Mediated Crosstalk between Kallikrein Family Members Including Prostate-Specific Antigen in Prostate Cancer

BACKGROUND

MicroRNAs mediate biological processes through preferential binding to the 3' untranslated region (3' UTR) of target genes. Studies have shown their association with prostate cancer (PCa) risk through single-nucleotide polymorphisms (SNPs), known as miRSNPs. In a European cohort, 22 PCa risk-associated miRSNPs have been identified. The most significant miRSNP in the 3' UTR of Kallikrein-related peptidase 3 (KLK3) created a binding site for miR-3162-5p. Here we investigated the miR-3162-5p-KLK interaction and the clinical implication of miR-3162-5p in PCa.

METHODS

We tested the role of miR-3162-5p in PCa etiology using IncuCyte live-cell imaging and anchorage-independent growth assays. The effect of miR-3162-5p on KLK and androgen receptor (AR) expression was measured by RT-quantitative (q)PCR and target pulldown assays. KLK3 proteolytic activity was determined by DELFIA^® immunoassay. Mass spectrometry identified pathways affected by miR-3162-5p. miR-3162-5p expression was measured in clinical samples using RT-qPCR.

RESULTS

miR-3162-5p affected proliferation, migration, and colony formation of LNCaP cells by regulating the expression of KLK2-4 and AR by direct targeting. KLK3 protein expression was regulated by miR-3162-5p consistent with lower KLK3 proteolytic activity observed in LNCaP-conditioned media. KLK/AR pulldown and mass spectrometry analysis showed a potential role of miR-3162-5p in metabolic pathways via KLK/AR and additional targets. Increased miR-3162-5p expression was observed in prostate tumor tissues with higher Gleason grade.

CONCLUSIONS

Our study provides an insight into possible involvement of miR-3162-5p in PCa etiology by targeting KLKs and AR. It highlights clinical utility of miR-3162-5p and its interactive axis as a new class of biomarkers and therapeutic targets for PCa.