RKIP regulates CCL5 expression to inhibit breast cancer invasion and metastasis by controlling macrophage infiltration

Ila Datar, Xiaoliang Qiu, Hong Zhi Ma, Miranda Yeung, Shweta Aras, Ivana de la Serna, Fahd Al-Mulla, Jean Paul Thiery, Robert Trumbly, Xuan Fan, Hongjuan Cui, Kam C. Yeung

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)


Accumulating evidence suggests that presence of macrophages in the tumor microenvironment add to the invasive and tumor-promoting hallmarks of cancer cells by secreting angiogenic and growth factors. RKIP is a known metastasis suppressor and interferes with several steps of metastasis. However, the mechanistic underpinnings of its function as a broad metastasis suppressor remain poorly understood. Here, we establish a novel pathway for RKIP regulation of metastasis inhibition through the negative regulation of RANTES/CCL5 thereby limiting tumor macrophage infiltration and inhibition of angiogenesis. Using a combination of loss- and gain-of- function approaches, we show that RKIP hinders breast cancer cell invasion by inhibiting expression of the CC chemokine CCL5 in vitro. We also show that the expression levels of RKIP and CCL5 are inversely correlated among clinical human breast cancer samples. Using a mouse allograft breast cancer transplantation model, we highlight that ectopic expression of RKIP significantly decreases tumor vasculature, macrophage infiltration and lung metastases. Mechanistically, we demonstrate that the inhibition of the CCL5 expression is the cause of the observed effects resulting from RKIP expression. Taken together, our results underscore the significance of RKIP as important negative regulator of tumor microenvironment.

Original languageEnglish
Pages (from-to)39050-39061
Number of pages12
Issue number36
Publication statusPublished - 1 Jan 2015


  • CCL5
  • Metastasis suppressor
  • RKIP
  • Tumor microenvironment


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