Prostate cancer (PCa) is a leading cause of mortality and morbidity in men worldwide, and emerging evidence suggests that the CD44(high) prostate tumor-initiating cells (TICs) are associated with its poor prognosis. Although microRNAs are frequently dysregulated in human cancers, the influence of microRNAs on PCa malignancy and whether targeting TIC-associated microRNAs inhibit PCa progression remain unclear. In this study, we found that miR-320 is significantly downregulated in PCa. Overexpression of miR-320 in PCa cells decreases PCa tumorigenesis in vitro and in vivo. Global gene expression profiling of miR-320-overexpressing PCa cells reveals that downstream target genes of Wnt/β-catenin pathway and cancer stem cell markers are significantly decreased. MicroRNA-320 inhibits β-catenin expression by targeting the 3'-untranslated region of β-catenin mRNA. The reduction of miR-320 associated with increased β-catenin was also found in CD44(high) subpopulation of prostate cancer cells and clinical PCa specimens. Interestingly, knockdown of miR-320 significantly increases the cancer stem-like properties, such as tumorsphere formation, chemoresistance and tumorigenic abilities, although enriching the population of stem-like TICs among PCa cells. Furthermore, increased miR-320 expression in prostate stem-like TICs significantly suppresses stem cell-like properties of PCa cells. These results support that miR-320 is a key negative regulator in prostate TICs, and suggest developing miR-320 as a novel therapeutic agent may offer benefits for PCa treatment.
Drug resistance is the main obstacle in the improvement of chemotherapeutic efficacy in glioblastoma. Previously, we showed that dehydroepiandrosterone (DHEA), one kind of androgen/neurosteroid, potentiates glioblastoma to acquire resistance through attenuating DNA damage. Androgen receptor (AR) activated by DHEA or other types of androgen was reported to promote drug resistance in prostate cancer. However, in DHEA-enriched microenvironment, the role of AR in acquiring resistance of glioblastoma remains unknown. In this study, we found that AR expression is significantly correlated with poor prognosis, and AR obviously induced the resistance to temozolomide (TMZ) treatment. Herein, we observed that ALZ003, a curcumin analog, induces FBXL2-mediated AR ubiquitination, leading to degradation. Importantly, ALZ003 significantly inhibited the survival of TMZ-sensitive and –resistant glioblastoma in vitro and in vivo. The accumulation of reactive oxygen species (ROS), lipid peroxidation and suppression of glutathione peroxidase (GPX) 4, which are characteristics of ferroptosis, were observed in glioblastoma cell after treatment of ALZ003. Furthermore, overexpression of AR prevented ferroptosis in the presence of GPX4. To evaluate the therapeutic effect in vivo, we transplanted TMZ-sensitive or -resistant U87MG cells into mouse brain followed by intravenous administration with ALZ003. In addition to inhibiting the growth of glioblastoma, ALZ003 significantly extended the survival period of transplanted mice, and significantly decreased AR expression in the tumor area. Taken together, AR potentiates TMZ resistance for glioblastoma, and ALZ003-mediated AR ubiquitination might open a new insight into therapeutic strategy for TMZ resistant glioblastoma.
Background: Increased IL-6 level, M2 macrophages and PD-1 + CD8 + T cells in tumor microenvironments (TME) have been identified to correlate with resistance to checkpoint blockade immunotherapy, yet the mechanism remains poorly understood. Rab small GTPase-mediated trafficking of cytokines is critical in immuno-modulation. We have previously reported dysregulation of Rab37 in lung cancer cells, whereas the roles of Rab37 in tumor-infiltrating immune cells and cancer immunotherapy are unclear. Methods: The tumor growth of the syngeneic mouse allograft in wild type or Rab37 knockout mice was analyzed. Imaging analyses and vesicle isolation were conducted to determine Rab37-mediated IL-6 secretion. STAT3 binding sites at PD-1 promoter in T cells were identified by chromatin immunoprecipitation assay. Multiplex fluorescence immunohistochemistry was performed to detect the protein level of Rab37, IL-6 and PD-1 and localization of the tumor-infiltrating immune cells in allografts from mice or tumor specimens from lung cancer patients. Results: We revealed that Rab37 regulates the secretion of IL-6 in a GTPase-dependent manner in macrophages to trigger M2 polarization. Macrophage-derived IL-6 promotes STAT3-dependent PD-1 mRNA expression in CD8 + T cells. Clinically, tumors with high stromal Rab37 and IL-6 expression coincide with tumor infiltrating M2-macrophages and PD1 + CD8 + T cells that predicts poor prognosis in lung cancer patients. In addition, lung cancer patients with an increase in plasma IL-6 level are found to be associated with immunotherapeutic resistance. Importantly, combined blockade of IL-6 and CTLA-4 improves survival of tumor-bearing mice by reducing infiltration of PD1 + CD8 + T cells and M2 macrophages in TME. Conclusions: Rab37/IL-6 trafficking pathway links with IL-6/STAT3/PD-1 transcription regulation to foster an immunosuppressive TME and combined IL-6/CTLA-4 blockade therapy exerts potent anti-tumor efficacy.
BackgroundCaregiver health is a crucial public health concern due to the increasing number of elderly people with disabilities. Elderly caregivers are more likely to have poorer health and be a care recipient than younger caregivers. The Taiwan government offers home-based long-term care (LTC) services to provide formal care and decrease the burden of caregivers. This study examined the effects of home-based LTC services on caregiver health according to caregiver age.MethodsThis cross-sectional study included a simple random sample of care recipients and their caregivers. The care recipients had used LTC services under the Ten-Year Long-Term Care Project (TLTCP) in Taiwan. Data were collected through self-administered questionnaires from September 2012 to January 2013. The following variables were assessed for caregivers: health, sex, marital status, education level, relationship with care recipient, quality of relationship with care recipient, job, household monthly income, family income spent on caring for the care recipient (%) and caregiving period. Furthermore, the following factors were assessed for care recipients: age, sex, marital status, education level, living alone, number of family members living with the care recipient, quality of relationship with family and dependency level. The health of the caregivers and care recipients was measured using a self-rated question (self-rated health [SRH] was rated as very poor, poor, fair, good and very good).ResultsThe study revealed that home nursing care was significantly associated with the health of caregivers aged 65 years or older; however, caregivers aged less than 65 who had used home nursing care, rehabilitation or respite care had poorer health than those who had not used these services. In addition, the following variables significantly improved the health of caregivers aged 65 years or older: caregiver employment, 20% or less of family income spent on caregiving than 81%–100% and higher care recipient health. The involvement of daughters-in-law, rather than spouses, and care recipient health were positively related to the health of caregivers aged less than 65 years.ConclusionsThe findings suggest that home-based LTC service use benefits the health of elderly caregivers. By contrast, home-based LTC service use may be negatively correlated with the health of the caregivers aged less than 65 years.Electronic supplementary materialThe online version of this article (10.1186/s12955-017-0786-6) contains supplementary material, which is available to authorized users.
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