2185

PTK2B

protein tyrosine kinase 2 beta;PTK2B;protein tyrosine kinase 2 beta

CAK-beta|FADK 2|PTK2B protein tyrosine kinase 2 beta|calcium-dependent tyrosine kinase|calcium-regulated non-receptor proline-rich tyrosine kinase|cell adhesion kinase beta|focal adhesion kinase 2|proline-rich tyrosine kinase 2|protein kinase B|protein-ty

8p21.1

protein-coding

Pyk2 and Src phosphorylation is initiated by CCL18, which promotes breast cancer metastasis via its functional G protein-coupled receptor PITPNM3. However, the function of Pyk2 and Src in CCL18-induced breast cancer metastasis is poorly understood. Quantitative reverse-transcription polymerase chain reactions (qRT-PCRs), Western blot, boyden chamber assay, and adherence assay were performed to delineate the consequences of Pyk2/Src in CCL18-induced breast cancer cells. Co-immunoprecipitation and immunofluorescence were performed to analyze the interaction of proteins. Upon the binding of CCL18 to PITPNM3, Pyk2 translocates from the cytoplasm to the plasma membrane to form a stable complex with PITPNM3, subsequently activating Src kinase. Moreover, upon stimulation with CCL18, Pyk2 and Src become essential for integrin alpha5/beta1 clustering-dependent adherence, migration, and invasion. Pyk2 and Src are important in CCL18-induced breast cancer metastasis.

Aberrant regulation in the chemotaxis and migration ability of cancer cells is closely associated with their metastatic activity. The chemokine receptor 7 (CCR7) has recently been shown to play an important role in regional lymph node metastasis of squamous cell carcinoma of the head and neck (SCCHN). In this study, we examined the role of proline-rich tyrosine kinase-2 (Pyk2) in CCR7-induced chemotaxis and migration ability of metastatic SCCHN cells. We showed that Pyk2 is overexpressed in squamous cell carcinoma of the head and neck. We also found that CCR7 induced Pyk2 and cofilin activation. Inhibition of Pyk2 activity using a pharmacological inhibitor, Tyrphostin A9, significantly attenuated CCR7-induced Pyk2 tyrosine phosphorylation, activation of cofilin and sequentially abolished F-actin rearrangment, diminished the chemotaxis and migration ability of SCCHN cells. In summary, our data suggest that CCR7 via Pyk2 and cofilin regulates the chemotaxis and migration ability of metastatic SCCHN cells.

RhoC is a member of the Ras-homologous family of genes which have been implicated in tumorigenesis and tumor progression. However, the exact role of RhoC is controversial and is yet to be clarified. We have examined the effect of RhoC on prostate tumor cells and found that RhoC had no effect on cell proliferation in vitro or on tumor growth in mice. However, RhoC significantly enhanced the metastatic ability of the tumor cells in these animals, suggesting that RhoC affects only the metastasis but not the growth of prostate tumor cells. The results of our immunohistochemical analyses on tumor specimens from 63 patients with prostate cancer indicate that RhoC expression had no significant correlation with Gleason grade. However, the expression of RhoC showed significant positive correlation with both lymph node and distant metastasis, and it was inversely correlated with patient survival. We also found that RhoC significantly augmented the invasion and motility of prostate tumor cells by activating matrix metalloproteinases 2 and 9 (MMP2 and MMP9) in vitro. The results of our antibody array analysis for signal molecules revealed that RhoC significantly activated kinases including mitogen-activated protein kinase (MAPK), focal adhesion kinase (FAK), Akt, and Pyk2. Inhibition of Pyk2 kinase blocked the RhoC-dependent activation of FAK, MAPK, and Akt, followed by the suppression of MMP2 and MMP9. Inhibitors of both MAPK and Akt also significantly blocked the activities of these MMPs. Therefore, our results indicate that RhoC promotes tumor metastasis in prostate cancer by sequential activation of Pyk2, FAK, MAPK, and Akt followed by the up-regulation of MMP2 and MMP9, which results in the stimulation of invasiveness of tumor cells.

Aberrant regulation in the chemotaxis and migration ability of cancer cells is closely associated with their metastatic activity. The chemokine receptor 7 (CCR7) has recently been shown to play an important role in regional lymph node metastasis of squamous cell carcinoma of the head and neck (SCCHN). In this study, we examined the role of proline-rich tyrosine kinase-2 (Pyk2) in CCR7-induced chemotaxis and migration ability of metastatic SCCHN cells. We showed that Pyk2 is overexpressed in squamous cell carcinoma of the head and neck. We also found that CCR7 induced Pyk2 and cofilin activation. Inhibition of Pyk2 activity using a pharmacological inhibitor, Tyrphostin A9, significantly attenuated CCR7-induced Pyk2 tyrosine phosphorylation, activation of cofilin and sequentially abolished F-actin rearrangment, diminished the chemotaxis and migration ability of SCCHN cells. In summary, our data suggest that CCR7 via Pyk2 and cofilin regulates the chemotaxis and migration ability of metastatic SCCHN cells.