Objective To determine if untreated HIV-1 infection and progression is associated with premature aging of memory CD8+ and CD4+ T cells and naive CD4+ T cells. Methods Twenty HIV-1–infected fast progressors and 40 slow progressors were included in our study, using risk set sampling. The expression of cell surface markers reflecting the differentiation stages of lymphocytes was measured using flow cytometry analyses performed on cryopreserved peripheral blood mononuclear cells. Results We found that HIV-1 disease progression is associated with a decreased CD28 median florescence intensity on CD4+ and CD8+ T cells; an increased proportion of intermediate- and late-differentiated CD8+ T cells and a decreased CD31 median florescence intensity on naive CD4+ T cells of recent thymic origin. A selective depletion of peripherally expanded naive CD4+ T cells was found to be associated with HIV-1 infection but not with HIV-1 disease progression. Conclusions The overall change during HIV-1 infection and progression is associated with a shift in the T-cell population toward an aged conformation, which may be further compromised by impaired renewal of the less-differentiated CD4+ T-cell population. Our results suggest that HIV-1 infection induces an accelerated aging of T lymphocytes, which is associated with the clinical progression to AIDS and death.

Regulatory T cells (Tregs) may play an important role in the immunopathology of chronic HIV-1 infection due to their potent suppressive activity of both T cell activation and effector function. To investigate the correlation between Tregs and immune activation during untreated chronic HIV-1 infection, we conducted a nested case–control study within the Multicenter AIDS Cohort Study (MACS). Twenty HIV-1-infected fast progressors (FP) and 40 slow progressors (SP) were included in our study using risk-set sampling. Nine age-matched HIV-1-uninfected men (UI) were also included. Cryopreserved peripheral blood mononuclear cells (PMBCs) were tested using flow cytometry analyses. We identified Tregs as Foxp3+CD25+CD4+ T cells and assessed the activation of CD4+ and CD8+ T cells by the expression of CD38, HLADR, or both markers simultaneously. There is a relative expansion of Tregs during HIV-1 infection, which is associated with disease progression. The increased CD38 expression on both CD4+ and CD8+ T cells expressed as either percentage or median fluorescence intensity (MFI) and the elevated proportion of CD8+ T cells that is HLADR+CD38+ were all associated with rapid HIV-1 progression. Counter to the assumed role of Tregs as the suppressors of activation, the expansion of Tregs was positively correlated with CD4+ T cell activation among HIV-1-infected fast progressors. The high level of Tregs associated with rapid HIV progression may suggest a detrimental role of these cells in the immune control of HIV-1 infection.

Invasion and metastasis are the major causes of death in patients with esophageal squamous cell carcinoma (ESCC). Epithelial-mesenchymal transition (EMT) is a critical step in tumor progression and transforming growth factor-β1 (TGF-β1) signaling has been shown to play an important role in EMT. In this study, we investigated how TGF-β1 signaling pathways contributed to EMT in three ESCC cell lines as well as 100 patients of nomadic ethnic Kazakhs residing in northwest Xinjiang Province of China. In vitro analyses included Western blotting to detect the expression of TGF-β1/Smad and EMT-associated proteins in Eca109, EC9706 and KYSE150 cell lines following stimulation with recombinant TGF-β1 and SB431542, a potent inhibitor of ALK5 that also inhibits TGF-β type II receptor. TGF-β-activated Smad2/3 signaling in EMT was significantly upregulated as indicated by mesenchymal markers of N-cadherin and Vimentin, and in the meantime, epithelial marker, E-cadherin, was markedly downregulated. In contrast, SB431542 addition downregulated the expression of N-cadherin and Vimentin, but upregulated the expression of E-cadherin. Moreover, the TGF-β1-induced EMT promoted invasion capability of Eca109 cells. Tumor cells undergoing EMT acquire fibroblastoid-like phenotype. Expressed levels of TGF-β1/Smad signaling molecules and EMT-associated proteins were examined using immunohistochemical analyses in 100 ESCC tissues of Kazakh patients and 58 matched noncancerous adjacent tissues. The results showed that ESCC tissues exhibited upregulated expression of TGF-β1/Smad. We also analyzed the relationship between the above proteins and the patients' clinicopathological characteristics. The TGF-β1/Smad signaling pathway in human Eca109 ESCC cells may carry similar features as in Kazakh ESCC patients, suggesting that TGF-β1/Smad signaling pathway may be involved in the regulation of EMT in ethnic Kazakh patients with ESCC from Xinjiang, China.

Phospholipase C epsilon 1 (PLCE1) is a susceptibility gene in esophageal squamous cell carcinoma (ESCC). Nevertheless, the role of PLCE1 in ESCC tumorigenesis has not been elucidated. In this study, we determined the function of PLCE1 and its regulatory microRNA (miRNA) in ESCC. PLCE1 protein was excessively expressed in ESCC and precancerous lesions compared with that in normal tissues. High PLCE1 expression levels in ESCC were significantly linked with poor overall survival. Knockdown of PLCE1 promoted the apoptosis, cytokine-induced apoptosis, and sensitivity of cancer cells to chemotherapeutic drugs but abrogated the proliferation and EMT phenotype of ESCC in vitro. Notably, miR-145 was newly identified as a potent repressor of PLCE1 expression by directly targeting the 3′UTR of PLCE1. MiR-145 also inhibited cell proliferation, migration, and metastasis, as well as controlled the cytoskeleton dynamics of esophageal cancer. Moreover, miR-145 was expressed at low levels in a large cohort of patients with ESCC and was inversely correlated with PLCE1 protein expression in cancer cells and tissues. These findings demonstrate that PLCE1 functions as tumor promoter in ESCC and can be suppressed by miR-145 through inhibition of PLCE1 translation. Hence, delivery of PLCE1-targeting miR-145 is a potential therapeutic approach for esophageal cancer.

Membrane type 1-matrix metalloproteinase (MT1-MMP) is associated with enhanced tumorigenicity in many cancers. A recent study has revealed that MT1-MMP induces epithelial-to-mesenchymal transition (EMT) in prostate and breast cancer cells. However, its role in esophageal squamous cell carcinoma (ESCC) has not been studied. Here, we investigated the role of MT1-MMP in the dissemination of ESCC. Expression of MT1-MMP was detected by immunohistochemistry and tissue microarray in 88 Kazakh ESCC patients. Western blotting was performed to detect endogenous and overexpressed exogenous MT1-MMP in the Eca109 and Eca9706 cell lines, respectively. Transwell assay was used to estimate MT1-MMP-induced invasion and metastasis. EMT-associated proteins were detected by immunohistochemistry and western blotting. The associations between the expression of MT1-MMP and EMT-associated proteins with clinicopathologic parameters were analyzed. Overexpression of MT1-MMP was confirmed in Kazakh ESCC patients. MT1-MMP levels were found to be correlated with the depth of tumor infiltration. MT1-MMP induced EMT in ESCC both in vivo and in vitro, N-cadherin and Vimentin expression was upregulated upon MT1-MMP transfection into cells. However, E-cadherin was found to be downregulated. MT1-MMP-induced EMT led to increase migration and invasion in ESCC cell lines. In conclusion, our results suggest that MT1-MMP promotes ESCC invasion and metastasis.