Emulation and evaluation of tumor cell combined chemotherapy in isotropic/anisotropic collagen fiber microenvironments.

The rapid emergence of anisotropic collagen fibers in the tissue microenvironment is a critical transition point in late-stage breast cancer. Specifically, the fiber orientation facilitates the likelihood of high-speed tumor cell invasion and metastasis, which pose lethal threats to patients. Thus, based on this transition point, one key issue is how to determine and evaluate efficient combination chemotherapy treatments in late-stage cancer. In this study, we designed a collagen microarray chip containing 241 high-throughput microchambers with embedded metastatic breast cancer cell MDA-MB-231-RFP. By utilizing collagen's unique structure and hydromechanical properties, the chip constructed three-dimensional isotropic and anisotropic collagen fiber structures to emulate the tumor cell microenvironment at early and late stages. We injected different chemotherapeutic drugs into its four channels and obtained composite biochemical concentration profiles. Our results demonstrate that anisotropic collagen fibers promote cell proliferation and migration more than isotropic collagen fibers, suggesting that the geometric arrangement of fibers plays an important role in regulating cell behavior. Moreover, the presence of anisotropic collagen fibers may be a potential factor leading to the poor efficacy of combined chemotherapy in late-stage breast cancer. We investigated the efficacy of various chemotherapy drugs using cell proliferation inhibitors paclitaxel and gemcitabine and tumor cell migration inhibitors 7rh and PP2. To ensure the validity of our findings, we followed a systematic approach that involved testing the inhibitory effects of these drugs. According to our results, the drug combinations' effectiveness could be ordered as follows: paclitaxel + gemcitabine > gemcitabine + 7rh > PP2 + paclitaxel > 7rh + PP2. This study shows that the biomimetic chip system not only facilitates the creation of a realistic in vitro model for examining the cell migration mechanism in late-stage breast cancer but also has the potential to function as an effective tool for future chemotherapy assessment and personalized medicine.

Lysine demethylase 1B (Kdm1b) enhances somatic reprogramming through inducing pluripotent gene expression and promoting cell proliferation.

Lysine demethylase 1B (Kdm1b) is known as an epigenetic modifier with demethylase activity against H3K4 and H3K9 histones and plays an important role in tumor progression and tumor stem cell enrichment. In this study, we attempted to elucidate the role of Kdm1b in somatic cell reprogramming. We found that exogenous expression of Kdm1b in human dermal fibroblasts (HDFs) can influence the epigenetic modifications of histones. Subsequent analysis further suggests that the overexpression of Kdm1b can promote cell proliferation, reprogram metabolism and inhibit cell apoptosis. In addition, a series of multipotent factors including Sox2 and Nanog, and several epigenetic factors that may reduce epigenetic barriers were upregulated to varying degrees. More importantly, HDFs transfected with the combination of Oct4 (POU5F1), Sox2, Klf4 and c-Myc and Kdm1b (OSKMK) achieved higher reprogramming efficiency. Therefore, we suggest that Kdm1b is an important epigenetic factor associated with pluripotency.

LMCD1 facilitates the induction of pluripotency via cell proliferation, metabolism, and epithelial-mesenchymal transition.

Somatic cell reprogramming was achieved by lentivirus mediated overexpression of four transcription factors called OSKM: OCT3/4, SOX2, KLF4, and c-MYC but it was not very efficient. Here, we reported that the transcription factor, LMCD1 (LIM and cysteine rich domains 1) together with OSKM can induce reprogramming of human dermal fibroblasts into induced pluripotent stem cells (iPSCs) more efficiently than OSKM alone. At the same time, the number of iPSCs clones were reduced when we knocked down LMCD1. Further study showed that LMCD1 can enhance the cell proliferation, the glycolytic capability, the epithelial-mesenchymal transition (EMT), and reduce the epigenetic barrier by upregulating epigenetic factors (EZH2, WDR5, BMI1, and KDM2B) in the early stage of reprogramming, making the cells more accessible to gain pluripotency. Additional research suggested that LMCD1 can not only inhibit the developmental gene GATA6, but also promote multiple signaling pathways, such as AKT and glycolysis, which are closely related to reprogramming efficiency. Therefore, we identified the novel function of the transcription factor LMCD1, which reduces the barriers of the reprogramming from somatic to pluripotent cells in several ways in the early stage of reprogramming.

An intermediate state in trans-differentiation with proliferation, metabolic, and epigenetic switching.

Although TGF-ß signaling can effectively activate fibroblasts to transform to myofibroblasts, the underlying mechanisms involved in the cell fate switching for trans-differentiation have not been fully elucidated. In this study, we found the evidence of an intermediate state in the process of trans-differentiation. In the early stage of trans-differentiation, cells enter the intermediate state first with multiple characteristics such as accelerating cell cycle, metabolic switching, enhanced anti-apoptotic ability, and pluripotency, which is very similar to the early stage of reprogramming. As the trans-differentiation continues, these characteristics get switched. Therefore, trans-differentiation appears to require the switching of cell proliferation ability, metabolic pathway, and "stemness" to complete the process. In this study, we can conclude that an intermediate state may be necessary with high pluripotency in trans-differentiation from fibroblasts to myofibroblasts. Only after passing the intermediate state, the trans-differentiation is finally completed and will not easily return to the original state.

Highly efficient nanomedicine from cationic antimicrobial peptide-protected Ag nanoclusters.

Designing the homogeneous assembly of the bio-nano interface to fine-tune the interactions between the nanoprobes and biological systems is of prime importance to improve the antimicrobial efficiency of nanomedicines. In this work, highly luminescent silver nanoclusters with the homogeneous conjugation of an antimicrobial peptide (referred to as Dpep-Ag NCs) were achieved via the reduction-decomposition-reduction process as a single package. The as-designed Dpep-Ag NCs inherited the two distinctive features of bactericides from the Ag+ species and the antimicrobial peptide of Dpep, and exhibited enhanced bacterial killing efficiency compared with other control groups including BSA-capped Ag NCs and the original antimicrobial peptide bactenecin (Opep)-protected Ag nanoparticles (Opep-Ag NPs). The ultrasmall size feature of Dpep-Ag NCs combined with the positively charged bactericidal tail allow a better interface and interaction with the cell membrane owing to the selective targeting of lipopolysaccharides in the Gram-negative bacteria and electrostatic interaction, facilitating the membrane permeability. Dpep-Ag NCs restrained the E. coli growth visibly and outperformed commercial Ag NPs (30 nm) with reduced (ca. 100-fold) minimal inhibitory concentration. The analysis of infected wound sizes and tissues treated with Dpep-Ag NCs in a murine model reveal obvious differences in the healing effect compared with the other counterparts, demonstrating its antibacterial efficiency in practical application.

Functionalized Graphene@Gold Nanostar/Lipid for Pancreatic Cancer Gene and Photothermal Synergistic Therapy under Photoacoustic/Photothermal Imaging Dual-Modal Guidance.

Nanomaterial-based pancreatic cancer treatment has received widespread attention and rapid development in the past few years. The major challenges include the poor combination of diagnosis and therapy, the difficulty in targeting therapy from the root and the unsatisfactory antitumor efficiency, which is accompanied by a great risk of relapse and metastasis. In this work, a positively charged lipid bilayer membrane is coated on reduced graphene oxide@gold nanostar (rGO@AuNS) for photoacoustic/photothermal dual-modal imaging-guided gene/photothermal synergistic therapy of pancreatic cancer. In addition, the cross-linking of folic acid on the surface of rGO@AuNS-lipid can specifically bind after recognizing folic acid receptors on the surface of cancer cells, and greatly improve the targeting ability of the nanomaterial and the performance of imaging diagnosis by receptor-mediated endocytosis. Moreover, the photothermal and gene (targeting G12V mutant K-Ras gene) synergistic therapy shows outstanding anticancer efficacy for pancreatic cancer tumor bearing mice, and it is noteworthy that the treatment groups have anti-liver metastasis of pancreatic cancer.