Osteosarcoma (OS) is the most frequent primary malignant bone tumor in urgent need of better therapies. Using genetically modified mouse models (GEMMs), we demonstrate that Wnt signaling promotes c-Fos-induced OS formation via the actions of the collagen-modifying enzyme Loxl2. c-Fos/AP-1 directly regulates the expression of the Wnt ligands Wnt7b and Wnt9a in OS cells through promoter binding, and Wnt7b and Wnt9a in turn promote Loxl2 expression in murine and human OS cells through the transcription factors Zeb1 and Zeb2. Concordantly, inhibition of Wnt ligand secretion by inactivating the Wnt-less (Wls) gene in osteoblasts in c-Fos GEMMs either early or in a therapeutic setting reduces Loxl2 expression and progression of OS. Wls-deficient osteosarcomas proliferate less, are less mineralized and are enriched in fibroblastic cells surrounded by collagen fibers. Importantly, Loxl2 inhibition using either the pan-Lox inhibitor BAPN or a specific inducible shRNA reduces OS cell proliferation in vitro and decreases tumor growth and lung colonization in murine and human orthotopic OS transplantation models. Finally, OS development is delayed in c-Fos GEMMs treated with BAPN or with specific Loxl2 blocking antibodies. Congruently, a strong correlation between c-FOS, LOXL2 and WNT7B/WNT9A expression is observed in human OS samples, and c-FOS/LOXL2 co-expression correlates with OS aggressiveness and decreased patient survival. Therefore, therapeutic targeting of Wnt and/or Loxl2 should be considered to potentiate the inadequate current treatments for pediatric, recurrent, and metastatic OS.

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Wnt signaling and Loxl2 promote aggressive osteosarcoma

Cancer cell migration plays a crucial role during the metastatic process. Reversible tyrosine phosphorylation by protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs) have been implicated in the regulation of cancer cell migration and invasion. However, the underlying mechanisms have not been fully elucidated. Here, we show that depletion of the FERM and PDZ domain-containing protein tyrosine phosphatase PTPN3 enhances lung cancer cell migration/invasion and metastasis by promoting actin filament assembly and focal adhesion dynamics. We further identified Src and DAAM1 (dishevelled associated activator of morphogenesis 1) as interactors of PTPN3. DAAM1 is a formin-like protein involved in the regulation of actin cytoskeletal remodeling. PTPN3 inhibits Src activity and Src-mediated phosphorylation of Tyr652 on DAAM1. The tyrosine phosphorylation of DAAM1 is essential for DAAM1 homodimer formation and actin polymerization. Ectopic expression of a DAAM1 phosphodeficient mutant inhibited F-actin assembly and suppressed lung cancer cell migration and invasion. Our findings reveal a novel mechanism by which reversible tyrosine phosphorylation of DAAM1 by Src and PTPN3 regulates actin dynamics and lung cancer invasiveness.

PTPN3 suppresses lung cancer cell invasiveness by counteracting Src-mediated DAAM1 activation and actin polymerization.

WNT5B, a member of the WNT family of proteins that is closely related to WNT5A, is required for cell migration, cell proliferation, or cell differentiation in many cell types. WNT5B signals through the non-canonical β-catenin-independent signaling pathway and often functions as an antagonist of canonical WNT signaling. Although WNT5B has a high amino acid identity with WNT5A and is often assumed to have similar activities, WNT5B often exhibits unique expression patterns and functions. Here, we describe the distinct effects and mechanisms of WNT5B on development, bone, adipose tissue, cardiac tissue, the nervous system, the mammary gland, the lung and hematopoietic cells, compared to WNT5A. We also highlight aberrances in non-canonical WNT5B signaling contributing to diseases such as osteoarthritis, osteoporosis, obesity, type 2 diabetes mellitus, neuropathology, and chronic diseases associated with aging, as well as various cancers.

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WNT5B in Physiology and Disease.

Background. Doublecortin-like kinase 1 (DCLK1) has been universally identified as a cancer stem cell (CSC) marker and is found to be overexpressed in many types of cancers including breast cancer. However, there is little data regarding the functional role of DCLK1 in breast cancer metastasis. In the present study, we sought to investigate whether and how DCLK1 plays a metastatic-promoting role in human breast cancer cells. Methods. We used Crispr/Cas9 technology to knock out DCLK1 in breast cancer cell line BT474, which basically possesses DCLK1 at a higher level, and stably overexpressed DCLK1 in another breast cancer cell line, T47D, that basically expresses DCLK1 at a lower level. We further analyzed the alterations of metastatic characteristics and the underlying mechanisms in these cells. Results. It was shown that, compared with the corresponding control cells, DCLK1 overexpression led to an increase in metastatic behaviors including enhanced migration and invasion of T47D cells. By contrast, forced depletion of DCLK1 drastically inhibited these metastatic characteristics in BT474 cells. Mechanistically, the epithelial-mesenchymal transition (EMT) program, which is critical for cancer metastasis, was prominently activated in DCLK1-overexpressing cancer cells, evidenced by a decrease in an epithelial marker ZO-1 and an enhancement in several mesenchymal markers including ZEB1 and Vimentin. In addition, DCLK1 overexpression induced the ERK MAPK pathway, which resultantly enhanced the expression of MT1-MMP that is also involved in cancer metastasis. Knockout of DCLK1 could reverse these events, further supporting a metastatic-promoting role for DCLK1. Conclusions. Collectively, our data suggested that DCLK1 overexpression may be responsible for the increased metastatic features in breast cancer cells. Targeting DCLK1 may become a therapeutic option for breast cancer metastasis.

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DCLK1 Plays a Metastatic-Promoting Role in Human Breast Cancer Cells.

Patients with chronic lymphocytic leukemia (CLL) have high plasma-levels of Wnt5a, which can induce phosphorylation of ERK1/2 and enhance CLL-cell proliferation. Such effects could be inhibited by treatment with an ERK1/2 inhibitor, ERK1/2-specific siRNA, or cirmtuzumab, an anti-ROR1 mAb. The CLL-derived line, MEC1, expresses Wnt5a, but not ROR1. MEC1 cells transfected to express ROR1 (MEC1-ROR1) had higher levels of phosphorylated ERK1/2 than parental MEC1, or MEC1 transfected with ROR1ΔPRD, a truncated ROR1 lacking the cytoplasmic proline-rich domain (PRD), or ROR1P808A a mutant ROR1 with a P→A substitution at 808, which is required for complexing with the Rac-specific-guanine-nucleotide-exchange factor DOCK2 upon stimulation with Wnt5a. We silenced DOCK2 with siRNA and found this repressed the capacity of Wnt5a to induce ERK1/2 phosphorylation in MEC1-ROR1 or CLL cells. CLL cells that expressed ROR1 had higher levels of phosphorylated ERK1/2 or DOCK2 than CLL cells lacking ROR1. Although we found ibrutinib could inhibit the phosphorylation of ERK1/2 and DOCK2 induced by B-cell-receptor ligation, we found that this drug was unable to inhibit Wnt5a-induced, ROR1-dependent phosphorylation of ERK1/2 or DOCK2. This study demonstrates that Wnt5a can induce activation of ERK1/2 and enhance CLL-cell proliferation via a ROR1/DOCK2-dependent pathway independent of BTK.

/pdf/wnt5a-enhances-proliferation-of-chronic-lymphocytic-leukemia-4pkn5tp8br.pdf

Wnt5a enhances proliferation of chronic lymphocytic leukemia and ERK1/2 phosphorylation via a ROR1/DOCK2-dependent mechanism.

WNT5A promotes migration and invasion of human osteosarcoma cells via SRC/ERK/MMP-14 pathway.

Objective: To investigate the expressions of receptor interacting protein kinase 4 (RIPK4), β-catenin and P-glycoprotein (P-gp) in osteosarcoma tissues and their clinical significance Methods: The expressions of RIPK4, β-catenin and P-gp in 36 specimens of osteosarcoma tissues and 15 specimens of osteochondroma tissues were detected by immunohistochemistry The correlations of RIPK4, β-catenin and P-gp expressions with clinical characteristics and prognosis of the patients with osteosarcoma were analyzed Results: The positive expression rates of RIPK4, β-catenin and P-gp in osteosarcoma tissues were 639%, 750% and 611%, respectively, which were higher than those in osteochondroma tissues (67%, 200% and 00%, respectively) (all P < 005) The expression of RIPK4 was associated with tumor size and Enneking stage of osteosarcoma (both P < 005) The expression of β-catenin was associated with Enneking stage of osteosarcoma (P < 005) The expression of P-gp was associated with Enneking stage and metastasis of osteosarcoma (both P < 005) There were positive correlation between RIPK4 and β-catenin (γ = 0634, P < 001),  β-catenin and P-gp (γ = 0461, P < 001), and RIPK4 and P-gp (γ = 0468, P < 001) in osteosarcoma tissues Kaplan-Meier analysis showed that the survival time of patients with RIPK4-, β-catenin- or P-gp-positive expression was shorter than that of the negative expression group (all P < 005) Univariate analysis of COX proportional hazards regression model revealed that age, Enneking stage, metastasis, RIPK4- and P-gp-positive expressions were relevant to the overall survival of patients with osteosarcoma (all P < 005) Multivariate analysis of COX proportional hazards regression model confirmed that age, metastasis and P-gp-positive expression could be as independent prognostic factors of osteosarcoma patients (all P < 005) Conclusion: The expressions of RIPK4, β-catenin and P-gp are high in osteosarcoma tissues and being related to the clinical characteristics of osteosarcoma The three proteins may play important roles in the development and progression of osteosarcoma, and they can affect the prognosis of osteosarcoma patients DOI:103781/jissn1000-7431201633205

Expressions of RIPK4, β-catenin and P-gp in osteosarcoma and their clinical significance

Multiple myeloma (MM) is the third most common malignant neoplasm of the hematological system. It often develops from monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) precursor states. In this process, the immune microenvironment interacts with the MM cells to exert yin and yang effects, promoting tumor progression on the one hand and inhibiting it on the other. Despite significant therapeutic advances, MM remains incurable, and the main reason for this may be related to the complex and variable immune microenvironment. Therefore, it is crucial to investigate the dynamic relationship between the immune microenvironment and tumors, to elucidate the molecular mechanisms of different factors in the microenvironment, and to develop novel therapeutic agents targeting the immune microenvironment of MM. In this paper, we review the latest research progress and describe the dual influences of the immune microenvironment on the development and progression of MM from the perspective of immune cells and molecules.

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The yin–yang effects of immunity: From monoclonal gammopathy of undetermined significance to multiple myeloma

LGR4 promotes tumorigenesis by activating TGF-β1/Smad signaling pathway in multiple myeloma.

Subsequently to the publication of the above article, the authors have realized that the same western blotting data shown for the vimentin bands for the U2OS cell line in Fig. 3B on p. 1159 had inadvertently been re‑used for the β‑catenin bands for the U2OS cell line in Fig. 5A on p. 1161. The authors have re‑examined their original data, and have realized that Fig. 5 was assembled incorrectly. The corrected version of Fig. 5, showing the correct β‑catenin bands for the U2OS cell line, is shown opposite. Note that this error did not quantitatively affect either the results or the overall conclusions reported in this paper. The authors are grateful to the Editor of Molecular Medicine Reports for allowing them this opportunity to publish a Corrigendum, and they apologize to the readership for any inconvenience caused. [the original article was published in Molecular Medicine Reports 21: 1154‑1162, 2020; DOI: 10.3892/mmr.2020.10939].

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Zhi-gang Yi

Papers

WNT5A promotes migration and invasion of human osteosarcoma cells via SRC/ERK/MMP-14 pathway.

Expressions of RIPK4, β-catenin and P-gp in osteosarcoma and their clinical significance

The yin–yang effects of immunity: From monoclonal gammopathy of undetermined significance to multiple myeloma

LGR4 promotes tumorigenesis by activating TGF-β1/Smad signaling pathway in multiple myeloma.

Silencing of RIPK4 inhibits epithelial-mesenchymal transition by inactivating the Wnt/β-catenin signaling pathway in osteosarcoma