CXCL12-mediated HOXB5 overexpression facilitates Colorectal Cancer metastasis through transactivating CXCR4 and ITGB3.

Background: Metastasis is the major reason for the high mortality of colorectal cancer (CRC). However, the molecular mechanism underlying CRC metastasis remains unclear. Here, we report a novel role of homeobox B5 (HOXB5), a member of the HOX family, in promoting CRC metastasis. Method: The expression of HOXB5 and its target genes were examined by immunohistochemistry in human CRC. Chromatin immunoprecipitation and luciferase reporter assays were performed to measure the transcriptional regulation of target genes by HOXB5. The metastatic capacities of CRC cells were evaluated by in vivo lung and liver metastatic models. Results: The elevated expression of HOXB5 was positively correlated with distant metastasis, higher AJCC stage, and poor prognosis in CRC patients. HOXB5 expression was an independent and significant risk factor for the recurrence and survival in CRC patients. Overexpression of HOXB5 promoted CRC metastasis by transactivating metastatic related genes, C-X-C motif chemokine receptor 4 (CXCR4) and integrin subunit beta 3 (ITGB3). C-X-C motif chemokine ligand 12 (CXCL12), which is the ligand of CXCR4, upregulated HOXB5 expression through the extracellular regulated protein kinase (ERK)/ETS proto-oncogene 1, transcription factor (ETS1) pathway. The knockdown of HOXB5 decreased CXCL12-enhanced CRC metastasis. Furthermore, AMD3100, a specific CXCR4 inhibitor, significantly suppressed HOXB5-mediated CRC metastasis. HOXB5 expression was positively correlated with CXCR4 and ITGB3 expression in human CRC tissues, and patients with positive co-expression of HOXB5/CXCR4, or HOXB5/ITGB3 exhibited the worst prognosis. Conclusion: Our study implicates HOXB5 as a prognostic biomarker in CRC, and defines a CXCL12-HOXB5-CXCR4 positive feedback loop that plays an important role in promoting CRC metastasis.

Feng W ，Huang W ，Chen J ，Qiao C ，Liu D ，Ji X ，Xie M ，Zhang T ，Wang Y ，Sun M ，Tian D ，Fan D ，Nie Y ，Wu K ，Xia L ... -  《Theranostics》

Homeobox B5 promotes metastasis and poor prognosis in Hepatocellular Carcinoma, via FGFR4 and CXCL1 upregulation.

Background: Since metastasis remains the main reason for HCC-associated death, a better understanding of molecular mechanism underlying HCC metastasis is urgently needed. Here, we elucidated the role of Homeobox B5 (HOXB5), a member of the HOX transcriptional factor family, in promoting HCC metastasis. Method: The expression of HOXB5 and its functional targets fibroblast growth factor receptor 4 (FGFR4) and C-X-C motif chemokine ligand 1 (CXCL1) were detected by immunohistochemistry. Luciferase reporter and chromatin immunoprecipitation assays were performed to measure the transcriptional regulation of target genes by HOXB5. The effects of FGFR4 and CXCL1 on HOXB5-mediated metastasis were analyzed by an orthotopic metastasis model. Results: Elevated expression of HOXB5 had a positive correlation with poor tumour differentiation, higher TNM stage, and indicated unfavorable prognosis. Overexpression of HOXB5 promoted HCC metastasis through transactivating FGFR4 and CXCL1 expression, whereas knockdown of FGFR4 and CXCL1 decreased HOXB5-enhanced HCC metastasis. Moreover, HOXB5 overexpression in HCC cells promoted myeloid derived suppressor cells (MDSCs) infiltration through CXCL1/CXCR2 axis. Either depletion of MDSCs by anti-Gr1 or blocking CXCL1-CXCR2 axis by CXCR2 inhibitor impaired HOXB5-mediated HCC metastasis. In addition, fibroblast growth factor 19 (FGF19) contributed to the HOXB5 upregulation through PI3K/AKT/HIF1α pathway. Overexpression of FGF15 (an analog of FGF19 in mouse) promoted HCC metastasis, whereas knockdown of HOXB5 significantly inhibited FGF15-enhanced HCC metastasis in immunocompetent mice. HOXB5 expression was positively associated with CXCL1 expression and intratumoral MDSCs accumulation in human HCC tissues. Patients who co-expressed HOXB5/CXCL1 or HOXB5/CD11b exhibited the worst prognosis. Furthermore, the combination of FGFR4 inhibitor BLU-554 and CXCR2 inhibitor SB265610 dramatically decreased HOXB5-mediated HCC metastasis. Conclusion: HOXB5 was a potential prognostic biomarker in HCC patients and targeting this loop may provide a promising treatment strategy for the inhibition of HOXB5-mediated HCC metastasis.

He Q ，Huang W ，Liu D ，Zhang T ，Wang Y ，Ji X ，Xie M ，Sun M ，Tian D ，Liu M ，Xia L ... -  《Theranostics》

Forkhead box K2 promotes human colorectal cancer metastasis by upregulating ZEB1 and EGFR.

Du F ，Qiao C ，Li X ，Chen Z ，Liu H ，Wu S ，Hu S ，Qiu Z ，Qian M ，Tian D ，Wu K ，Fan D ，Nie Y ，Xia L ... -  《Theranostics》

Exosome-encapsulated miRNAs contribute to CXCL12/CXCR4-induced liver metastasis of colorectal cancer by enhancing M2 polarization of macrophages.

Tumor-associated macrophages (TAMs) are important immunocytes associated with cancer metastasis. However, whether TAMs play a dominant role in mediating CXCL12/CXCR4-induced liver metastasis of colorectal cancer (CRC) remains unexplored. Herein, we found that CD206+ TAMs, which infiltrated at the invasive front, were correlated with CXCR4 expression and liver metastasis of CRC in clinical specimens. Several miRNAs (miR-25-3p, miR-130b-3p, miR-425-5p), upregulated in CRC cells by activation of the CXCL12/CXCR4 axis, could be transferred to macrophages via exosomes. These exosomal miRNAs induced M2 polarization of macrophages by regulating PTEN through activation of PI3K/Akt signaling pathway. In turn, M2 polarized macrophages promoted cancer metastasis by enhancing epithelial-mesenchymal transition (EMT) and secreting vascular endothelial growth factor (VEGF). Co-culture of CRC cells with macrophages transfected with these miRNAs or treated with exosomes enhanced their metastatic capacity both in vitro and in vivo. Clinically, the serum levels of exosomal miR-25-3p, miR-130b-3p and miR-425-5p were correlated with progression and metastasis of CRC. In conclusion, these results reveal a crucial role of exosomal miRNAs in mediating the crosstalk between CXCR4 overexpressing cancer cells and TAMs, providing potential therapeutic targets for circumventing liver metastasis of CRC.

Wang D ，Wang X ，Si M ，Yang J ，Sun S ，Wu H ，Cui S ，Qu X ，Yu X ... -  《-》

TGF-β1-Induced SOX18 Elevation Promotes Hepatocellular Carcinoma Progression and Metastasis Through Transcriptionally Upregulating PD-L1 and CXCL12.

Hepatocellular carcinoma (HCC) is characterized by an immune-suppressive microenvironment, which contributes to tumor progression, metastasis, and immunotherapy resistance. Identification of HCC-intrinsic factors regulating the immunosuppressive microenvironment is urgently needed. Here, we aimed to elucidate the role of SYR-Related High-Mobility Group Box 18 (SOX18) in inducing immunosuppression and to validate novel combination strategies for SOX18-mediated HCC progression and metastasis. The role of SOX18 in HCC was investigated in orthotopic allografts and diethylinitrosamine/carbon tetrachloride-induced spontaneous models by using murine cell lines, adeno-associated virus 8, and hepatocyte-specific knockin and knockout mice. The immune cellular composition in the HCC microenvironment was evaluated by flow cytometry and immunofluorescence. SOX18 overexpression promoted the infiltration of tumor-associated macrophages (TAMs) and regulatory T cells (Tregs) while diminishing cytotoxic T cells to facilitate HCC progression and metastasis in cell-derived allografts and chemically induced HCC models. Mechanistically, transforming growth factor-beta 1 (TGF-β1) upregulated SOX18 expression by activating the Smad2/3 complex. SOX18 transactivated chemokine (C-X-C motif) ligand 12 (CXCL12) and programmed death ligand 1 (PD-L1) to induce the immunosuppressive microenvironment. CXCL12 knockdown significantly attenuated SOX18-induced TAMs and Tregs accumulation and HCC dissemination. Antagonism of chemokine receptor 4 (CXCR4), the cognate receptor of CXCL12, or selective knockout of CXCR4 in TAMs or Tregs likewise abolished SOX18-mediated effects. TGFβR1 inhibitor Vactosertib or CXCR4 inhibitor AMD3100 in combination with anti-PD-L1 dramatically inhibited SOX18-mediated HCC progression and metastasis. SOX18 promoted the accumulation of immunosuppressive TAMs and Tregs in the microenvironment by transactivating CXCL12 and PD-L1. CXCR4 inhibitor or TGFβR1 inhibitor in synergy with anti-PD-L1 represented a promising combination strategy to suppress HCC progression and metastasis.

Chen J ，Feng W ，Sun M ，Huang W ，Wang G ，Chen X ，Yin Y ，Chen X ，Zhang B ，Nie Y ，Fan D ，Wu K ，Xia L ... -  《-》