Yaming Li

Post-Mastectomy Radiotherapy for Breast Cancer Patients with T1-T2 and 1-3 Positive Lymph Nodes: a Meta-Analysis

Background The role of post-mastectomy radiotherapy (PMRT) in patients with T1-2 and 1-3 positive lymph nodes remains controversial. The aim of this study is to investigate the possible benefits of PMRT for this subgroup. Methods Three electronic databases were systematically quarried (Cochrane Library, MEDLINE, and EMBASE) for published studies evaluating the effects of PMRT on breast cancer patients with T1-T2 tumors with 1-3 positive lymph nodes. Of the 334 studies identified, information was available for 3432 patients from 10 clinical studies. Pooled relative risk estimates (RR) and overall survival (OS) were calculated using the inverse variance weighted approach, publication bias and chi-square test were also calculated. Results From the 10 studies, the pooled RR (RRs) for locoregional recurrence (LRR) with PMRT was 0.348 (95% CI = 0.254 to 0.477), suggesting a significant benefit for PMRT to decrease the risk of LRR in patients with T1-T2 tumors and 1-3 positive nodes (p<0.05). Reporting bias ( Begg’s p = 0.152; Egger’s p = 0.107) or significant heterogeneity (Cochran’s p = 0.380; I2 = 6.7%) were not detected. For further subset analysis, the RR for T1, N1-3+ tumors was 0.330 (95% CI = 0.171 to 0.639); for T2, N1-3+ tumors the RR was 0.226 (95% CI = 0.121 to 0.424). The pooled RR for overall survival (OS) was not significantly different between PMRT and no-PMRT group (1.051, 95% CI =1.001 to 1.104). Conclusions Our pooled analysis revealed that PMRT significantly reduces the risk of LRR in patients with TI-T2 tumors with 1-3 positive nodes, and the magnitude of the LRR risk reduction is slightly greater for larger tumors. Our results suggest that PMRT should be considered for patients with T1/T2 tumors with 1-3 positive nodes to decrease the relatively high risk of LRR.

MicroRNA-99a inhibits tumor aggressive phenotypes through regulating HOXA1 in breast cancer cells.

MicroRNAs (miRNAs) are key regulators of tumor progression. Based on microarray data, we identified miR-99a as a potential tumor suppressor in breast cancer. Expression of miR-99a is frequently down-regulated in breast cancer tissues relative to normal breast tissues. Reduced miR-99a expression was highly associated with lymph node metastasis and shorter overall survival of patients with breast cancer. Gain- and loss-of-function studies revealed that, miR-99a significantly inhibits breast cancer cell proliferation, migration, and invasion. An integrated bioinformatics analysis identified HOXA1 mRNA as the direct functional target of miR-99a, and this regulation was confirmed by luciferase reporter assay. Furthermore, we showed for the first time that HOXA1 expression is elevated in breast cancer tissues. Knockdown of HOXA1 significantly inhibited breast cancer cell proliferation, migration and invasion, and restoration of HOXA1 partially rescued the inhibitory effect of miR-99a in breast cancer cells. Collectively, our data indicate that miR-99a plays a tumor-suppressor role in the development of breast cancer, and could serve as a potential therapeutic target for breast cancer treatment.

The anticancer effect of Huaier (Review)

Trametes robiniophila Murr. (Huaier) is a sandy beige mushroom found on the trunks of trees and has been widely used in traditional Chinese medicine (TCM) for ~1,600 years. The anticancer effects of Huaier have attracted increasing worldwide interest in recent years. Accumulating evidence suggests that the anticancer mechanism of Huaier may be associated with various biological activities, such as inhibition of cell proliferation, anti-metastasis, interference with tumor angiogenesis and tumor-specific immunomodulatory effect. Animal and experimental studies suggest that Huaier is a promising anticancer agent. Further clinical research is warranted to illustrate the untapped chemopreventive and therapeutic potential of Huaier either alone or in conjunction with existing therapies.

Huaier Extract Induces Autophagic Cell Death by Inhibiting the mTOR/S6K Pathway in Breast Cancer Cells

Huaier extract is attracting increased attention due to its biological activities, including antitumor, anti-parasite and immunomodulatory effects. Here, we investigated the role of autophagy in Huaier-induced cytotoxicity in MDA-MB-231, MDA-MB-468 and MCF7 breast cancer cells. Huaier treatment inhibited cell viability in all three cell lines and induced various large membranous vacuoles in the cytoplasm. In addition, electron microscopy, MDC staining, accumulated expression of autophagy markers and flow cytometry revealed that Huaier extract triggered autophagy. Inhibition of autophagy attenuated Huaier-induced cell death. Furthermore, Huaier extract inhibited the mammalian target of the rapamycin (mTOR)/S6K pathway in breast cancer cells. After implanting MDA-MB-231 cells subcutaneously into the right flank of BALB/c nu/nu mice, Huaier extract induced autophagy and effectively inhibited xenograft tumor growth. This study is the first to show that Huaier-induced cytotoxicity is partially mediated through autophagic cell death in breast cancer cells through suppression of the mTOR/S6K pathway.

Huaier extract suppresses breast cancer via regulating tumor-associated macrophages.

Macrophages in tumor microenvironment are mostly M2-polarized - and have been reported to promote tumorigenesis, which are also defined as tumor-associated macrophages (TAMs). Here, we examined the regulatory effects of Huaier extract on TAMs using RAW264.7 murine macrophage cell line. Our data demonstrated that Huaier extract could inhibit the infiltration of macrophages into tumor microenvironment in a dose-dependent manner. By performing RT-PCR, immunofluorescence and phagocytosis assay, we were able to find that Huaier extract could regulate the polarization of macrophages, with decreased M2-polarization and increased phagocytosis of RAW264.7 cells. Moreover, we identified that Huaier extract could suppress macrophages-induced angiogenesis by using HUVEC migration assay, tube formation and chorioallantoic membrane assay. Additionally, western blotting showed decreased expression of MMP2, MMP9 and VEGF with the use of Huaier extract. Finally, we found that Huaier extract could inhibit M2-macrophages infiltration and angiogenesis through treating 4T1 tumor bearing mice with Huaier extract. Our study revealed a novel mechanism of the anti-tumor effect of Huaier extract which inhibited angiogenesis by targeting TAMs. These findings provided that Huaier was a promising drug for clinical treatment of breast cancer.

Hedgehog pathway is involved in nitidine chloride induced inhibition of epithelial-mesenchymal transition and cancer stem cells-like properties in breast cancer cells

BackgroundThe complications of clinical metastatic disease are responsible for the majority of breast cancer related deaths, and fewer therapies substantially prolong survival. Nitidine chloride (NC), a natural polyphenolic compound, has been shown to exhibit potent anticancer effects in many cancer types, including breast cancer. The epithelial-mesenchymal transition (EMT) and the acquisition of cancer stem cells (CSCs)-like properties emerge as critical steps in the metastasis of human cancers. However, the effects of NC on the EMT and the CSCs-like properties in breast cancer cells, and the underlying molecular mechanisms are not fully understood.ResultsIn the present study, MDA-MB-468 and MCF-7 cancer cells were treated with NC. Scratch and Transwell assays were performed to determine whether NC could attenuate the migratory and invasive capability of cancer cells; Mammosphere formation and flow cytometry analysis were performed to confirm that NC decreased CSCs-like phenotype; RT-PCR and western blot analysis were used to examine the expression level of EMT and CSC related markers in both cells. Mechanistically, NC could inhibit the components of Hedgehog pathway (smoothened, patched, Gli1 and Gli2), subsequently inhibited the expression of Snail, Slug and Zeb1, which were correlated with the significant changes of the expression of EMT related markers (N-cadherin, E-cadherin, and Vimentin) to reverse EMT. On the other hand, NC could also inhibit the expression of CSCs related factors such as Nanog, Nestin, Oct-4 and CD44 via Hedgehog pathway. Furthermore, transforming growth factor-β1 (TGF-β1)-induced increment of EMT and CSCs properties could be reversed by NC.ConclusionsTaken together, these data indicated that NC suppressed breast cancer EMT and CSCs-like properties through inhibiting Hedgehog signaling pathway. Our study suggested that NC may be a potential anticancer agent for breast cancer.

Huaier extract synergizes with tamoxifen to induce autophagy and apoptosis in ER-positive breast cancer cells

Tamoxifen (TAM) is the most widely used endocrine therapy for estrogen receptor (ER)-positive breast cancer patients, but side effects and the gradual development of insensitivity limit its application. We investigated whether Huaier extract, a traditional Chinese medicine, in combination with TAM would improve treatment efficacy in ER-positive breast cancers. MTT, colony formation, and invasion and migration assays revealed that the combined treatment had stronger anticancer effects than either treatment alone. Huaier extract enhanced TAM-induced autophagy, apoptosis, and G0/G1 cell cycle arrest, as measured by acidic vesicular organelle (AVO) staining, TUNEL, flow cytometry, and western blot. Additionally, combined treatment inhibited tumorigenesis and metastasis by suppressing the AKT/mTOR signaling pathway. Huaier extract also enhanced the inhibitory effects of TAM on tumor growth in vivo in a xenograft mouse model. These results show that Huaier extract synergizes with TAM to induce autophagy and apoptosis in ER-positive breast cancer cells by suppressing the AKT/mTOR pathway.

Long noncoding RNA LINP1 acts as an oncogene and promotes chemoresistance in breast cancer

ABSTRACT Recent studies have shown that long non-coding RNAs (lncRNAs) are involved in a number of biological processes; however, further study is still warranted to comprehensively reveal their functions. In this study, we showed that the lncRNA in non-homologous end joining (NHEJ) pathway 1 (LINP1) was related to breast cancer cell proliferation, metastasis and chemoresistance. Loss- and gain-of function studies were used to assess the role of LINP1 in promoting breast cancer progression. LINP1 knockdown mitigated breast cancer cell growth by inducing G1-phase cell cycle arrest and apoptosis. LINP1 also promoted breast cancer cell metastasis and influenced the expression of epithelial-mesenchymal transition-related markers. We identified p53 as a regulator of LINP1, and LINP1 overexpression could restore the metastatic effects of p53. Furthermore, LINP1 was upregulated in doxorubicin- and 5-fluorouracil-resistant cells and induced chemoresistance. We also observed that LINP1 enrichment played a critical functional role in chemoresistance by inhibiting chemotherapeutics-induced apoptosis. Moreover, LINP1 in tumors was associated with lower overall survival and disease-free survival. In conclusion, LINP1 may serve as a potential oncogene and chemoresistance-related regulator of breast cancer cells, suggesting that LINP1 might be a potent therapeutic target and might reduce chemoresistance in breast cancer.

A novel long non-coding RNA-PRLB acts as a tumor promoter through regulating miR-4766-5p/SIRT1 axis in breast cancer

Accumulating evidence indicates that long non-coding RNAs (lncRNAs) play a critical role in cancerous processes as either oncogenes or tumor suppressor genes. Here, we demonstrated that lncRNA-PRLB (progression-associated lncRNA in breast cancer) was upregulated in human breast cancer tissues and breast cancer cell lines. Further evaluation verified that lncRNA-PRLB was positively correlated with the extent of metastasis, and its expression was correlated with shorter survival time of breast cancer patients. We identified microRNA miR-4766-5p as an inhibitory target of lncRNA-PRLB. Both lncRNA-PRLB overexpression and miR-4766-5p knockdown could remarkably enhance cell growth, metastasis, and chemoresistance. We also determined that sirtuin 1 (SIRT1) was an inhibitory target of miR-4766-5p, and that SIRT1 was inhibited by both lncRNA-PRLB knockdown and miR-4766-5p overexpression. Significantly, we found that the promotion of cell proliferation and metastasis, the acquisition of chemoresistance, and the increased expression of SIRT1 induced by lncRNA-PRLB overexpression could be partly abrogated by ectopic expression of miR-4766-5p. Taken together, our findings indicated that lncRNA could regulate the progression and chemoresistance of breast cancer via modulating the expression levels of miR-4766-5p and SIRT1, which may have a pivotal role in breast cancer treatment and prognosis prediction.

MiR-770 suppresses the chemo-resistance and metastasis of triple negative breast cancer via direct targeting of STMN1

Chemo-resistance and metastasis of triple negative breast cancer (TNBC) contributed the most of treatment failure in the clinic. MicroRNAs (miRNAs) have been proved to be involved in many biological processes and diseases. In this study, we aimed to determine the role of miR-770 in the regulation of chemo-resistance and metastasis of TNBC. Clinically, miR-770 was highly expressed in chemo-sensitive tissues and predicted a better prognosis of TNBC. Functionally, ectopic expression of miR-770 suppressed the doxorubicin-resistance of TNBC cell lines via regulation of apoptosis and tumor microenvironment, which was mediated by exosomes. Moreover, miR-770 overexpression inhibited the migration and invasion. Rescue of STMN1 could partly reverse the effect of miR-770 in TNBC behaviors. Furthermore, we also demonstrated that overexpression of miR-770 inhibited DOX resistance and metastasis in vivo. Taken together, our results proved that miR-770 could suppress the doxorubicin-resistance and metastasis of TNBC cells, which broaden our insights into the underlying mechanisms in chemo-resistance and metastasis, and provided a new prognostic marker for TNBC cells.