Targeting of RAGE-ligand signaling impairs breast cancer cell invasion and metastasis

Abstract

The receptor for advanced glycation end products (RAGE) is highly expressed in various cancers and is correlated with poorer outcome in breast and other cancers. Here we tested the role of targeting RAGE by multiple approaches in the tumor and tumor microenvironment, to inhibit the metastatic process. We first tested how RAGE impacts tumor cell-intrinsic mechanisms using either RAGE overexpression or knockdown with short hairpin RNAs (shRNAs). RAGE ectopic overexpression in breast cancer cells increased MEK-EMT (MEK-epithelial-to-mesenchymal transition) signaling, transwell invasion and soft agar colony formation, and in vivo promoted lung metastasis independent of tumor growth. RAGE knockdown with multiple independent shRNAs in breast cancer cells led to decreased transwell invasion and soft agar colony formation, without affecting proliferation. In vivo, targeting RAGE shRNA knockdown in human and mouse breast cancer cells, decreased orthotopic tumor growth, reduced tumor angiogenesis and recruitment of inflammatory cells, and markedly decreased metastasis to the lung and liver in multiple xenograft and syngeneic mouse models. To test the non-tumor cell microenvironment role of RAGE, we performed syngeneic studies with orthotopically injected breast cancer cells in wild-type and RAGE-knockout C57BL6 mice. RAGE-knockout mice displayed striking impairment of tumor cell growth compared with wild-type mice, along with decreased mitogen-activated protein kinase signaling, tumor angiogenesis and inflammatory cell recruitment. To test the combined inhibition of RAGE in both tumor cell-intrinsic and non-tumor cells of the microenvironment, we performed in vivo treatment of xenografted tumors with FPS-ZM1 (1 mg/kg, two times per week). Compared with vehicle, FPS-ZM1 inhibited primary tumor growth, inhibited tumor angiogenesis and inflammatory cell recruitment and, most importantly, prevented metastasis to the lung and liver. These data demonstrate that RAGE drives tumor progression and metastasis through distinct tumor cell-intrinsic and -extrinsic mechanisms, and may represent a novel and therapeutically viable approach for treating metastatic cancers.

In�vitro anticancer effects of a RAGE inhibitor discovered using a structure-based drug design system

“…Previous experimental studies have revealed that inhibiting RAGE suppressed tumor growth, invasion and angiogenesis in multiple types of cancer (10,16,38). The therapeutic efficacy of blocking RAGE from interacting with HMGB-1 was initially demonstrated in glioma cells, in which this blockade inhibited tumor growth and invasion (16). Subsequently, strategies and components of RAGE inhibition have been reported in oncology and other fields, including neurology (39,40).…”

“…Therefore, blocking RAGE and ligand-RAGE signaling could represent a potential strategy for treating certain types of cancer. Previous experimental studies have revealed that inhibiting RAGE suppressed tumor growth, invasion and angiogenesis in multiple types of cancer (10,16,38). The therapeutic efficacy of blocking RAGE from interacting with HMGB-1 was initially demonstrated in glioma cells, in which this blockade inhibited tumor growth and invasion (16).…”

“…In addition, blocking RAGE signaling in tumor-associated macrophages has been proposed as a potential anticancer strategy; the macrophages form the tumor microenvironment, which could drive tumor angiogenesis (30). FPS-ZM1 directly inhibited primary tumor growth; in addition, it blocked RAGE signaling in tumor-associated macrophages, inhibited tumor angiogenesis and inflammatory cell recruitment and inhibited metastasis to the lungs and liver (16). Another RAGE-binding peptide, RP-1, was demonstrated to inhibit Aβ-induced cellular stress in human neuroblastoma cells in vitro (43).…”

“…HMGB-1 was revealed to induce RAS-related C3 botulinum toxin substrate (Rac)1 and cell division control protein 42 homolog (Cdc42) functions in RAGE-expressing HT1080 fibrosarcoma cells (10). Epidemiological studies also demonstrated that RAGE expression was associated with tumor malignancies of the stomach (11), colon and rectum (12)(13)(14), prostate (15), breast (16) and bone (17). Therefore, these previous studies suggested that RAGE represents a potential therapeutic target, and that inhibiting RAGE may be useful to anticancer strategies.…”

The impact of psychosocial stress and stress management on immune responses in patients with cancer

“…Because research has implicated inflammation and leukocyte recruitment in breast cancer progression, next, the same investigators explored whether SM‐related changes in leukocyte transcriptional activities during primary treatment could explain the effects of CBSM on increased the time to recurrence in this cohort. To examine whether the immunologic changes observed after CBSM over the initial 12 months of primary treatment predicted 11‐year disease‐free survival, the investigators used a 53‐gene composite, including 19 proinflammatory transcripts and 34 transcripts (inversely scored) related to type I IFN responses and antibody synthesis, based on prior research on stress and adversity .…”