Expression of the SIBLINGs and their MMP partners in human benign and malignant prostate neoplasms

The Potential of Extracellular Matrix- and Integrin Adhesion Complex-Related Molecules for Prostate Cancer Biomarker Discovery

Prostate cancer is among the top five cancer types according to incidence and mortality. One of the main obstacles in prostate cancer management is the inability to foresee its course, which ranges from slow growth throughout years that requires minimum or no intervention to highly aggressive disease that spreads quickly and resists treatment. Therefore, it is not surprising that numerous studies have attempted to find biomarkers of prostate cancer occurrence, risk stratification, therapy response, and patient outcome. However, only a few prostate cancer biomarkers are used in clinics, which shows how difficult it is to find a novel biomarker. Cell adhesion to the extracellular matrix (ECM) through integrins is among the essential processes that govern its fate. Upon activation and ligation, integrins form multi-protein intracellular structures called integrin adhesion complexes (IACs). In this review article, the focus is put on the biomarker potential of the ECM- and IAC-related molecules stemming from both body fluids and prostate cancer tissue. The processes that they are involved in, such as tumor stiffening, bone turnover, and communication via exosomes, and their biomarker potential are also reviewed.

Involvement of Dmp1 in the Precise Regulation of Hair Bundle Formation in the Developing Cochlea

Dentin matrix protein 1 (Dmp1) is a highly phosphorylated, extracellular matrix protein that is extensively expressed in bone and teeth but also found in soft tissues, including brain and muscle. However, the functions of Dmp1 in the mice cochlea are unknown. Our study showed that Dmp1 was expressed in auditory hair cells (HCs), with the role of Dmp1 in those cells identified using Dmp1 cKD mice. Immunostaining and scanning electron microscopy of the cochlea at P1 revealed that Dmp1 deficiency in mice resulted in an abnormal stereociliary bundle morphology and the mispositioning of the kinocilium. The following experiments further demonstrated that the cell-intrinsic polarity of HCs was affected without apparent effect on the tissue planer polarity, based on the observation that the asymmetric distribution of Vangl2 was unchanged whereas the Gαi3 expression domain was enlarged and Par6b expression was slightly altered. Then, the possible molecular mechanisms of Dmp1 involvement in inner ear development were explored via RNA-seq analysis. The study suggested that the Fgf23-Klotho endocrine axis may play a novel role in the inner ear and Dmp1 may regulate the kinocilium-stereocilia interaction via Fgf23-Klotho signaling. Together, our results proved the critical role of Dmp1 in the precise regulation of hair bundle morphogenesis in the early development of HCs.

Implication of Prophetic Variables and their Impulsive Interplay in CA Prostate Patients Experiencing Osteo-Metastasis

AIMS

To identify variables having a critical role in prostate cancer patients experiencing osteometastasis.

BACKGROUND

Prostatic carcinoma is a multifactorial complex disorder that exhibits an increased propensity to develop bone metastasis. An interplay of inflammatory and bone remodeling parameters promotes the formation of pre-metastatic niches in bones of patients, which could render them more vulnerable to skeletal disabilities.

OBJECTIVE

To evaluate the multi-dynamic inter-relationship of circulating variables in prostate cancer patients experiencing osteo-metastasis.

MATERIALS AND METHODS

Fifty-seven (n=57) men with clinically confirmed prostate cancer, fifty-nine (n=59) with skeletal metastases, and one hundred (n=100) healthy subjects i.e., men aging from 53-84 years with no clinical evidence of prostate were recruited from the Jinnah Hospital Lahore, Pakistan. Informed consent was obtained, and a venous blood sample was drawn and stored at -70oC until assayed. Levels of variables were evaluated using appropriate methods. Levels of Matrix Metalloproteinases (MMPs), Osteopontin (OPN), TGH- β, and sRANKL were estimated by the ELISA method. Each sample was suspended and the given protocol was employed. ELISA readings were obtained for the estimation of all variables.

RESULTS

Highly significant (P˂0.05) differential expression of oxidative stress, inflammatory cytokines, and bone remodeling variables were observed in localized and osteo-metastatic CA prostate patients. A strong positive correlation was revealed among OPN, sRANKL, MMP-7, MMP-9, PSA, and TGF-β (OPN vs. MMP-7, r=0.698* and OPN vs. MMP-9, r=0.765**, OPN vs. RANKL, =0.856*, sRANKL vs. MMP-9, r=0.825**, TGF- β vs. RANKL, r=0.868* and PSA vs. TGF- β, r=0.752*); lower levels of OPG were estimated in metastasized patients, showing that both osteolytic and osteoblastic phases of bone remodeling occur simultaneously.

CONCLUSION

The altered oxidative and inflammatory responses endorse Matrix Metalloproteinases (MMPs) increased activity, RANKL/OPG imbalance, and enhanced bone matrix proteins turnover, which can foster the process of osteo-metastasis. The perturbed RANKL/OPG drift and enhanced PSA levels are associated with increased TGF-β activity to aggravate Epithelial Mesenchymal transition (EM) and osteo-tropism of prostate cancer. Thus, designing novel targets of these major variables can minimize the incidence of prostate cancer patients.

Clinicopathological and prognostic significance of osteopontin expression in patients with prostate cancer: a systematic review and meta-analysis

Background: Evaluation of the feasibility for osteopontin (OPN) to serve as a biomarker in the prognosis and clinical-pathological features of prostate cancer (PCA) patients.

Methods: The original publications related to OPN and PCA were comprehensively searched in the online databases, including PubMed, Embase, Cochrane Library, Web of Science, Medline, Wanfang and China National Knowledge Infrastructure up to August 2019. Results were analyzed by Revman 5.3 and Stata 12.0.

Results: A total of 21 studies were included in the analysis and the result showed that the positive OPN expression group had a lower overall survival than the negative expression group (univariate: hazards ratio (HR) = 2.32, 95% confidence interval (95% CI) [1.74, 3.10], multivariate: HR = 2.41, 95% CI [1.63, 3.57]) and a lower biochemical relapse-free survival than the negative group (univariate: HR = 1.42, 95% CI [0.92, 2.17], multivariate: HR = 1.61, 95% CI [1.39, 1.87]). In addition, there was a higher expression level of OPN in PCA tissues than in normal prostate tissues (OR = 46.55, 95% CI [12.85, 168.59], P<0.00001) and benign prostatic hyperplasia (BPH) tissues (OR = 11.07, 95% CI [3.43, 35.75], P<0.0001). Moreover, OPN positive expression was also related to high Gleason score (OR = 2.64, 95% CI [1.49, 4.70], P=0.0009), high TNM stage (OR = 3.15, 95% CI [1.60, 6.20, P=0.0009), high Whitmore–Jewett stage (OR = 2.53, 95% CI [1.06, 6.03], P=0.04), high lymph node (OR = 3.69, 95% CI [1.88, 7.23], P=0.0001), and distant metastasis (OR = 8.10, 95% CI [2.94, 22.35], P=0.01). There was no difference observed in the differentiation of PCA (OR = 1.79, 95% CI [0.39, 8.33], P=0.46).

Conclusion: OPN could be recognized as a promising diagnostic and prognostic biomarker for PCA patients.

Targeting ABL1 or ARG Tyrosine Kinases to Restrict HIV-1 Infection in Primary CD4+ T-Cells or in Humanized NSG Mice

BACKGROUND

Previous studies support dasatinib as a potent inhibitor of HIV-1 replication. However, a functional distinction between 2 kinase targets of the drug, ABL1 and ARG, has not been assessed.

SETTING

We used primary CD4 T-cells, CD8-depleted peripheral blood mononuclear cells (PBMCs) from a treatment naïve HIV-1 patient, and a humanized mouse model of HIV-1 infection. We assessed the roles of ABL1 and ARG during HIV-1 infection and use of dasatinib as a potential antiviral against HIV-1 in humanized mice.

METHODS

Primary CD4 T-cells were administered siRNA targeting ABL1 or ARG, then infected with HIV-1 containing luciferase reporter viruses. Quantitative polymerase chain reaction of viral integration of 4 HIV-1 strains was also assessed. CD8-depleted PBMCs were treated for 3 weeks with dasatinib. NSG mice were engrafted with CD34 pluripotent stem cells from human fetal cord blood, and infected with Ba-L virus after 19 weeks. Mice were treated daily with dasatinib starting 5 weeks after infection.

RESULTS

siRNA knockdown of ABL1 or ARG had no effect on viral reverse transcripts, but increased 2-LTR circles 2- to 4-fold and reduced viral integration 2- to 12-fold. siRNA knockdown of ARG increased SAMHD1 activation, whereas knockdown of either kinase reduced RNA polymerase II activation. Treating CD8-depleted PBMCs from a treatment-naïve patient with 50 nM of dasatinib for 3 weeks reduced p24 levels by 99.8%. Ba-L (R5)-infected mice injected daily with dasatinib showed a 95.1% reduction in plasma viral load after 2 weeks of treatment.

CONCLUSIONS

We demonstrate a novel nuclear role for ABL1 and ARG in ex vivo infection experiments, and proof-of-principle use of dasatinib in a humanized mouse model of HIV-1 infection.

Bone sialoprotein-αvβ3 integrin axis promotes breast cancer metastasis to the bone

The underlying mechanisms of breast cancer cells metastasizing to distant sites are complex and multifactorial. Bone sialoprotein (BSP) and αvβ3 integrin were reported to promote the metastatic progress of breast cancer cells, particularly metastasis to bone. Most theories presume that BSP promotes breast cancer metastasis by binding to αvβ3 integrin. Interestingly, we found the αvβ3 integrin decreased in BSP silenced cells (BSPi), which have weak ability to form bone metastases. However, the relevance of their expression in primary tumor and the way they participate in metastasis are not clear. In this study, we evaluated the relationship between BSP, αvβ3 integrin levels, and the bone metastatic ability of breast cancer cells in patient tissues, and the data indicated that the αvβ3 integrin level is closely correlated to BSP level and metastatic potential. Overexpression of αvβ3 integrin in cancer cells could reverse the effect of BSPi in vitro and promote bone metastasis in a mouse model, whereas knockdown of αvβ3 integrin have effects just like BSPi. Moreover, The Cancer Genome Atlas data and RT‐PCR analysis have also shown that SPP1, KCNK2, and PTK2B might be involved in this process. Thus, we propose that αvβ3 integrin is one of the downstream factors regulated by BSP in the breast cancer‐bone metastatic cascade.

Interleukin-8 promotes prostate cancer bone metastasis through upregulation of bone sialoprotein

The aim of the present study was to investigate whether interleukin-8 (IL-8) enhances the ability of prostate cancer bone metastasis by influencing the coding level of bone sialoprotein (BSP). Cultured prostate cancer cell lines LNCaP (androgen dependent) and DU145 (androgen independent) were divided into three groups: IL-8 treatment group; IL-8 receptor inhibitor (SB225002) treatment group; and control group. Western blotting and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were used to detect BSP protein and mRNA expression levels. Matrigel and bone adhesion experiments were used to detect the invasiveness of cancer cells and bone adhesion changes. Compared with the control group, western blotting and RT-qPCR results indicated that BSP protein and mRNA levels in LNCaP and DU145 were significantly upregulated following IL-8 treatment. Matrigel experiments indicated that following IL-8 treatment, the invasiveness of LNCaP and DU145 cells was significantly increased. The results of bone adhesion experiments indicated that following IL-8 treatment, the number of DU145 cells adhered to the surface of the bone was increased, compared with the control group. Following treatment of both cell lines with SB225002, western blotting and RT-qPCR results indicated that the expression levels of BSP protein and mRNA were significantly downregulated. Matrigel experiments indicated that following SB225002 treatment, the invasiveness of LNCaP and DU145 cells was significantly reduced. The number of DU145 cells adhered to the surface of the bone was reduced, compared with the untreated group. Therefore, IL-8 may promote prostate cancer bone metastasis by enhancing BSP regulation.

Survey of dentin sialophosphoprotein and its cognate matrix metalloproteinase-20 in human cancers

Background

Matrix metalloproteinases‐20 (MMP20) expression is widely regarded as tooth specific, with expression limited to dental hard tissues. Recently, we reported MMP20 expression and interaction with dentin sialophosphoprotein (DSPP), a member of the Small Integrin Binding Ligand N‐linked Glycoproteins (SIBLINGs), in human oral squamous cell carcinoma (OSCC) and dysplastic oral premalignant lesions (OPLs), suggesting a role for MMP20‐DSPP interaction in oral carcinogenesis.

Methods

This study aimed to survey the expression of MMP20 and its cognate DSPP partner in the breast, colon, prostate, thyroid, and cervical neoplasms. Using commercially available tissue microarrays (TMAs) and cell lines, we performed immunohistochemistry, immunofluorescence, proximity ligation assay, and western blot experiments to determine the expressions of MMP20 and DSPP in the breast, colon, prostate, thyroid, cervical neoplasms, and their normal counterparts.

Results

Significantly high expression levels of MMP20 and DSPP were observed in the malignant breast, colon, prostate, thyroid, and cervical neoplasms compared with their benign and normal counterparts. Furthermore, MMP20 levels increased with advanced stages of colon and thyroid cancers. DSPP expression increased significantly with tumor stage in all cancers examined.

Conclusions

The co‐localization and potential MMP20‐DSPP interaction previously reported in oral cancers are present in other cancers. These results suggest MMP20‐DSPP pairing as a potential marker of disease activity in some epithelial cancers with diagnostic and prognostic implications.

Dentin matrix protein 1 correlates with the severity of hemorrhagic fever with renal syndrome and promotes hyper-permeability of endothelial cells infected by Hantaan virus

Hantaviruses are the major causative agents of hemorrhagic fever with renal syndrome (HFRS) in humans, which is characterized by increased capillary permeability. Dentin matrix protein 1 (DMP1) has been shown to degrade components of the basal membrane and interendothelial junctions via matrix metalloproteinase-9. To study the changes of serum DMP1 in HFRS, we determined the concentration of DMP1 using sandwich enzyme-linked immunosorbent assay. We found that serum DMP1 concentrations increased significantly, and reached peak value during the oliguric phase and in the critical group in HFRS patients. Moreover, serum DMP1 concentrations were closely related to blood urea nitrogen, creatinine, cystatin C, and vascular endothelial growth factor (VEGF). We further explored the role of DMP1 in HTNV-infected human umbilical vein endothelial cells (HUVECs) model. Data from immunocytochemistry showed that VEGF and tumor necrosis factor-α (TNF-α) promoted the expression of DMP1 on HTNV-infected HUVECs. Results from transwell assays demonstrated that the permeability of HUVECs increased significantly after HTNV infection with the addition of DMP1, VEGF, and TNF-α. This study suggests that elevated DMP1 concentrations may be associated with disease stage, severity, and the degree of acute kidney injury. DMP1 is involved in the regulation of capillary permeability in HFRS caused by hantavirus infection.

Interferon γ suppresses dentin sialophosphoprotein in oral squamous cell carcinoma cells resulting in antitumor effects, via modulation of the endoplasmic reticulum response

The expression of proinflammatory cytokines in various malignant neoplasms is widely considered to represent the host immune response to tumor development. The role of interferon (IFN)γ in head and neck squamous cell carcinoma, and its association with endoplasmic reticulum (ER) stress pathways, remains a subject of ongoing investigation. Dentin sialophosphoprotein (DSPP), which is a member of the small integrin-binding N-linked glycoproteins family, has been implicated in malignant transformation and invasion of oral squamous cell carcinoma (OSCC). Recent studies have established matrix metalloproteinase (MMP)20 as the cognate MMP partner of DSPP. The present study examined the effects of IFNγ treatment on DSPP and MMP20 expression, ER stress, the unfolded protein response (UPR), and calcium (Ca) homeostasis regulatory mechanisms in OSCC cells. The OSC2 OSCC cell line was treated with IFNγ at specific time-points. At each time-point, the mRNA expression levels of DSPP and MMP20, and those of ER-stress-, UPR- and Ca homeostasis-associated proteins [78-kDa glucose-regulated protein (GRP78), sarco/endoplasmic reticulum Ca²⁺-ATPase (SERCA2b), inositol 1,4,5-trisphosphate receptor (IP3r), protein kinase R-like ER kinase (PERK) and inositol-requiring enzyme 1 (IRE1)], were assessed by reverse transcription-quantitative polymerase chain reaction. The protein expression levels of B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), proliferating cell nuclear antigen (PCNA) and cytochrome c were analyzed by western blotting. Cell viability, apoptosis and migration were evaluated by MTT, Annexin V-fluorescein isothiocyanate flow cytometry and wound-healing assays, respectively. IFNγ treatment significantly downregulated the mRNA expression levels of the major ER stress regulator GRP78 and, to a lesser extent, the UPR-associated molecule IRE1; however, IFNγ had no significant effect on PERK. With regards to ER Ca homeostasis molecules, treatment with IFNγ downregulated the mRNA expression levels of SERCA2b and upregulated those of IP3r. Furthermore, DSPP and MMP20 mRNA expression levels were significantly reduced following IFNγ treatment. Notably, treatment with IFNγ hampered OSC2 migration, reduced cell viability and PCNA protein expression, enhanced apoptosis, downregulated Bcl-2, and upregulated Bax and cytochrome c. Overall, IFNγ inhibited OSCC cell viability and migration, and increased apoptosis, possibly by regulating ER stress and UPR mechanisms. In addition, IFNγ-induced DSPP and MMP20 downregulation may correspond with alteration in ER Ca homeostasis.

The tumorigenic role of DSPP and its potential regulation of the unfolded protein response and ER stress in oral cancer cells

Dentin sialophosphoprotein (DSPP) is upregulated in various human cancers, including head and neck squamous cell carcinoma. Cancer cells are commonly found under constant endoplasmic reticulum (ER) stress and exhibit increased levels of misfolded proteins, due to gene mutations and a stressful microenvironment. The present study examined the effects of DSPP silencing on the regulation of ER stress and the unfolded protein response (UPR) in oral cancer cells. A recently established stable DSPP short hairpin (sh)RNA-silenced OSC2 oral cancer cell line was used. The mRNA expression levels of ER stress-associated proteins, including 78 kDa glucose-regulated protein (GRP78), sarcoplasmic/endoplasmic reticulum calcium ATPase 2b (SERCA2b), inositol 1,4,5-trisphosphate receptor (IP3r), protein kinase R-like endoplasmic reticulum kinase (PERK), serine/threonine-protein kinase/endoribonuclease IRE1 (IRE1), activating transcription factor 6 (ATF6) and matrix metalloproteinase 20 (MMP20), were assessed by reverse transcription-quantitative polymerase chain reaction. The expression levels of apoptosis-related [B‑cell lymphoma 2 (Bcl2), Bcl2-associated X protein (Bax) and cytochrome c] and cell proliferation-related [proliferating cell nuclear antigen (PCNA)] proteins were analyzed by western blotting. Cell viability, apoptosis and migration were monitored by MTT assay, Annexin V-fluorescein isothiocyanate flow cytometry and wound-healing assay, respectively. In transiently transfected puromycin‑free OSC2 cells, DSPP silencing markedly downregulated the mRNA expression levels of major ER stress regulators, including GRP78, SERCA2b, PERK, IRE1 and ATF6, as well as MMP20. DSPP silencing also resulted in decreased cell viability and migration, and enhanced apoptosis. Furthermore, PCNA and Bcl2 levels were decreased, whereas Bax and cytochrome c protein levels were increased in DSPP-silenced OSC2 cells. Sustained puromycin treatment partially counteracted the effects of DSPP silencing on the mRNA expression levels of ER stress-related proteins and MMP20, and on the migratory capacity of OSC2 cells. However, following puromycin treatment of DSPP-silenced cells, cell viability was further reduced and apoptosis was enhanced. In conclusion, these data provide evidence to suggest that DSPP may be involved in ER stress mechanisms in oral squamous cell carcinoma, since its downregulation in OSC2 cells led to significant alterations in the levels of major ER stress-associated proteins, and subsequent collapse of the UPR system.

DSPP-MMP20 gene silencing downregulates cancer stem cell markers in human oral cancer cells

BACKGROUND

Recent findings indicate that dentin sialophosphoprotein (DSPP) and matrix metalloproteinase (MMP) 20 interact in oral squamous cell carcinoma (OSCC). The objective of this study was to determine the effects of DSPP/MMP20 gene silencing on oral cancer stem cell (OCSC) markers.

METHODS

The expression of well-established OCSC markers: ABCG2; ALDH1; CD133; CD44; BMI1; LGR4, and Podoplanin in DSPP/MMP20-silenced OSCC cell line, OSC2, and controls were assayed by western blot (WB), and flow cytometry techniques. The sensitivity of OSC2 cells to cisplatin following DSPP/MMP20 silencing was also determined.

RESULTS

DSPP/MMP20 silencing resulted in downregulation of OCSC markers, more profoundly ABCG2 (84%) and CD44 (81%), following double silencing. Furthermore, while treatment of parent (pre-silenced) OSC2 cells with cisplatin resulted in upregulation of OCSC markers, DSPP/MMP20-silenced OSC2 cells similarly treated resulted in profound downregulation of OCSC markers (72 to 94% at 50 μM of cisplatin), and a marked reduction in the proportion of ABCG2 and ALDH1 positive cells (~ 1%).

CONCLUSIONS

We conclude that the downregulation of OCSC markers may signal a reduction in OCSC population following MMP20/DSPP silencing in OSCC cells, while also increasing their sensitivity to cisplatin. Thus, our findings suggest a potential role for DSPP and MMP20 in sustaining OCSC population in OSCCs, possibly, through mechanism(s) that alter OCSC sensitivity to treatment with chemotherapeutic agents such as cisplatin.

SB225002 inhibits prostate cancer invasion and attenuates the expression of BSP, OPN and MMP‑2

The mechanisms of malignant cell metastasis to secondary sites are complex and multifactorial. Studies have demonstrated that small integrin-binding ligand N-linked glycoproteins (SIBLINGs), particularly bone sialoprotein (BSP) and osteopontin (OPN), are involved in neoplastic growth and metastasis. SIBLINGs promote malignant cell invasion and metastasis by enhancing matrix metalloproteinase 2 (MMP-2) and MMP-9 expression. Moreover, BSP and OPN can combine with integrin, which is located on the tumor cell surface, to further promote the malignant behavior of tumor cells. In the present study, we investigated whether SB225002, a specific CXCR2 receptor antagonist, can inhibit prostate cancer cell expression of BSP and OPN and reduce cancer cell invasion ability. A series of experiments showed that after SB225002 treatment, the proliferation, invasion and migration of two androgen-independent prostate cancer cell lines were inhibited, but this inhibitory effect was not observed on androgen-dependent prostate cancer cells. Western blotting showed that the PI3K signaling pathway could regulate the expression of SIBLING and MMP family proteins, and SB22055 could reduce the expression of BSP, OPN and MMP-2 in prostate cancer cells by inhibiting AKT/mTOR phosphorylation. Finally, in vivo experiments confirmed that SB225002 inhibited the proliferation of prostate cancer cells in vivo, and the expression levels of BSP, OPN and MMP-2 were also inhibited.