CCR4 drives ATLL jail break

Chemokine CCL17 induced by hypoxia promotes the proliferation of cervical cancer cell

Cervical cancer is often associated with hypoxia and many kinds of chemokines. But the relationship and role of hypoxia and Chemokine (C-C motif) ligand 17 (CCL17) in cervical cancer are still unknown. Here, we found that CCL17 was high expressed in cervical cancer. HeLa and SiHa cells could secrete CCL17 in a time-dependent manner. Hypoxia increased expression of CCL17 receptor (CCR4) on HeLa and SiHa cells. Treatment with recombination human CCL17 (rhCCL17) led to an elevation of cell proliferation in HeLa and SiHa cells in a dose-dependent manner. In contrast, blocking CCL17 with anti-human CCL17 neutralizing antibody (α-CCL17) played an oppose effect. However, rhCCL17 had no effect on apoptosis in cervical cancer cells. Further analysis showed that hypoxia promoted the proliferation of HeLa and SiHa cells, and these effects could be reversed by α-CCL17. Stimulation with the inhibitor for c-Jun N-terminal kinase (JNK) or signal transducers and activator of transcription 5 (STAT5) signal pathway not only directly decreased the proliferation of HeLa and SiHa cells, but also abrogated the stimulatory effect of rhCCL17 on the proliferation of HeLa and SiHa cells. These results suggest that a high level of CCL17 in cervical cancer lesions is an important regulator in the proliferation of cervical cancer cells through JNK and STAT5 signaling pathways. In this process, hypoxia magnifies this effect by up-regulating CCR4 expression and strengthening the interaction of CCL17/CCR4.

Modes of Human T Cell Leukemia Virus Type 1 Transmission, Replication and Persistence

Human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus that causes cancer (Adult T cell Leukemia, ATL) and a spectrum of inflammatory diseases (mainly HTLV-associated myelopathy—tropical spastic paraparesis, HAM/TSP). Since virions are particularly unstable, HTLV-1 transmission primarily occurs by transfer of a cell carrying an integrated provirus. After transcription, the viral genomic RNA undergoes reverse transcription and integration into the chromosomal DNA of a cell from the newly infected host. The virus then replicates by either one of two modes: (i) an infectious cycle by virus budding and infection of new targets and (ii) mitotic division of cells harboring an integrated provirus. HTLV-1 replication initiates a series of mechanisms in the host including antiviral immunity and checkpoint control of cell proliferation. HTLV-1 has elaborated strategies to counteract these defense mechanisms allowing continuous persistence in humans.