Xiangming He

Introduction: Breast cancer constitutes the most common invasive neoplasm among women, with triple-negative breast cancer (TNBC) representing 10–20% of all cases and lacking a standardized therapeutic approach. Chemotherapy remains the cornerstone of treatment for TNBC patients. Objective: Our research aimed to identify urinary metabolomic biomarkers capable of discerning chemotherapeutic response variability. Methods: In this study, we utilized a nuclear magnetic resonance (NMR)-based urinary metabolomics technique to evaluate the metabolic profiles of TNBC patients exhibiting diverse chemotherapeutic responses. Results: We found that the relative abundance of urinary metabolites effectively differentiated TNBC patients based on chemosensitivity. Multivariate receiver operating characteristic curve analysis indicated potential biomarkers indicative of chemotherapy responsiveness across three patient cohorts. Pathway analysis suggested perturbations in aminoacyl-tRNA biosynthesis; arginine, aspartate, and glutamate metabolism; and valine, leucine, and isoleucine biosynthesis in the pCR subgroup, and in arginine and proline metabolism, aminoacyl-tRNA biosynthesis, and histidine metabolism in the pathological partial response subgroup. Conclusion: Our NMR metabolomic data suggest that urinary metabolites hold potential as predictors of chemotherapy sensitivity in TNBC patients.

Regulatory T cells (Tregs), particularly the CD4+CD25+Foxp3+ Tregs, down regulate immunity and promote tumor cell growth by directly suppressing CD8+ and CD4+ T cells. Alternatively they can promote tumor growth by generating interleukin-10 (IL-10) and transforming growth factor β (TGFβ) in situ, which help tumor cells to evade the immune system. In vivo tumor models were prepared via subcutaneous injection with a suspension of B16 melanoma cells into the left upper flank of C57BL/6 J mice. The mice were randomized into five groups: radiotherapy (RT), chemotherapy (CT), radiochemotherapy (RCT), Inteferon α (INFα) groups, and a control group. Flow cytometry was used to determine the Tregs levels in the spleen and peripheral blood, and immunohistochemistry was performed to determine the expression levels of TGFβ and IL-10 in the tumor microenvironment. Tumor weight was significantly reduced in the CT or RCT groups (40.91 % and 41.83 %, respectively), while the reduction in tumor weight was relatively lower for the RT and IFNα groups (15.10 % and 13.15 %, respectively). The flow cytometry results showed that the ratios of CD4+CD25+Foxp3+ Tregs to lymphocytes and CD4+ cells in the spleen and in peripheral blood were significantly decreased after treatment with IFNα (P < 0.05). Expression of TGFβ and IL-10 in the tumor microenvironment in the CT and RT groups was higher compared with the control group (P < 0.01), while the expression of TGFβ and IL-10 in the INFα group was not significantly different (P > 0.05). The results show that INFα-2b inhibits cancer cell immune evasion by decreasing the levels of CD4+CD25+Foxp3+ Tregs and suppressing the expression of TGFβ and IL-10 in the tumor microenvironment.

Cell cycle regulatory pathway is a well-established pathway mainly dependent on cyclin-dependent kinases (CDKs), which are regulated positively by cyclins and negatively by cyclin-dependent kinase inhibitors(CKIs). Cyclin-dependent kinase 2 associate protein 1(CDK2-AP1) is a specific negative regulatory protein for CDK2, is important in the cancer cell cycle. However, the function of CDK2-AP1 in breast cancer remains unclear. We designed therefore explored the effects of CDK2-AP1 on breast cancer growth and its chemo-sensitivity. Expression of CDK2-AP1, CDK2 and CyclinD1 in 209 cases of pathological specimens using IHC staining was measured. Lost-of-function and Gain-of-function assays were used in vivo and in vitro relating to the specific role of CDK2-AP1 in breast cancer. We analyzed in vivo and in vitro the impact of CDK2-AP1 on chemotherapy sensitivity in breast cancer. The positive ratio of CDK2-AP1 expression was reduced successively in normal breast tissue, DCIS, invasive breast cancer and relapsed breast cancer, however, with CDK2 and CyclinD1 it was suggested that CDK2-AP1 was correlated closely with the tumorigenesis and progress, and might work as a tumor suppressor. After down-regulating CDK2-AP1 in breast cancer cells, the cell cycle was accelerated and cell proliferation enhanced. The cell cycle was arrested in G0/G1 phase and G2/M phase after up-regulating CDK2-AP1 in breast cancer cells, inhibiting cell proliferation. The expression of CDK2 and CyclinD1 changed accordingly after downregulation or upregulation of CDK2-AP1 by western blot, suggesting a role of the CDK2-AP1/CDK2/CyclinD1 cell cycle pathway in the initiation and progression of breast cancer. Similar results were obtained in animal assays. The data indicates that CDK2-AP1 can induce sensitivity to docetaxel treatment in breast cancer cells. CDK2-AP1 affects tumorigenesis, tumor growth and chemo-sensitivity by cell cycle regulation, which can potentially to be a therapeutical agent in breast cancer.