Expression of cyclin A and bone morphogenetic protein receptors and response to induction therapy in patients with acute leukemias

The BMP pathway: A unique tool to decode the origin and progression of leukemia

The microenvironment (niche) governs the fate of stem cells (SCs) by balancing self-renewal and differentiation. Increasing evidence indicates that the tumor niche plays an active role in cancer, but its important properties for tumor initiation progression and resistance remain to be identified. Clinical data show that leukemic stem cell (LSC) survival is responsible for disease persistence and drug resistance, probably due to their sustained interactions with the tumor niche. Bone morphogenetic protein (BMP) signaling is a key pathway controlling stem cells and their niche. BMP2 and BMP4 are important in both the normal and the cancer context. Several studies have revealed profound alterations of the BMP signaling in cancer SCs, with major deregulations of the BMP receptors and their downstream signaling elements. This was illustrated in the hematopoietic system by pioneer studies in chronic myelogenous leukemia that may now be expanded to acute myeloid leukemia and lymphoid leukemia, as reviewed here. At diagnosis, cells from the leukemic microenvironment are the major providers of soluble BMPs. Conversely, LSCs display altered receptors and downstream BMP signaling elements accompanied by altered functional responses to BMPs. These studies reveal the role of BMPs in tumor initiation, in addition to their known effects in later stages of transformation and progression. They also reveal the importance of BMPs in fueling cell transformation and expansion by overamplifying a natural SC response. This mechanism may explain the survival of LSCs independently of the initial oncogenic event and therefore may be involved in resistance processes.

Low expression of BMPRIB indicates poor prognosis of breast cancer and is insensitive to taxane-anthracycline chemotherapy

Bone morphogenetic protein receptor type IB (BMPRIB) is one osteogenesis factor, which function in breast cancer has been rarely explored until recently. In the clinical study presented here, involving a cohort of 368 invasive ductal carcinoma (IDC) patients, we identified that patients with low expression of BMPRIB exhibited poor prognosis, especially in the luminal B subtype. We also provided the first piece of evidence that low level of BMPRIB was a promoting factor for breast cancer patients to develop bone metastasis, but not lung, liver or brain. The first of its kind, we reported that patients with high expression of BMPRIB exhibited favorable prognosis by a retrospective analysis consisting of 168 patients treated with TE (taxane and anthracycline) regimens. And the patients with high expression of BMPRIB were more sensitive to TE regimens in the detection of 32 paired pre-neoadjuvant and post-neoadjuvant specimens. Overall, our study concluded that low expression of BMPRIB indicated poor prognosis of breast cancer and was insensitive to taxane-anthracycline chemotherapy. Our findings also lay a foundation to help clinicians improve identification of patients for TE regimens by BMPRIB in the era of precision medicine.