Nanoformulated quinacrine regulates NECTIN-4 domain specific functions in cervical cancer stem cells

NECTIN-4 [a poliovirus receptor-related-4 (PVRL-4) encoded gene] has vital roles in cancer proliferation, metastasis and angiogenesis. It possesses three different domains and it is predicted that they have different roles in cancer but the structure-function relationship is still unknown and hence carrying out a detailed study to elucidate the domain-specific functions of NECTIN-4 in cancer is necessary. Using 5-Fluouracil-resistant cervical cancer stem cells (PEMT-5FU-R-MC) and different NECTIN-4 domain-specific constructs, different domains of NECTIN-4 were over-expressed in PEMT-5FU-R-MC cells. Biochemical assays like comet, γ-H2AX immunofluorescence, western blot, in vitro tube formation, gelatin zymography, in ovo CAM assay, etc. were used to delineate the function of each domain of NECTIN-4 in cancer and their regulation by nano-formulated quinacrine (NQC). Endo-domain (lacking extracellular region corresponding to aa 30-347) and ecto-domain (lacking signal peptide and cytoplasmic region corresponding to aa 1-29 and 348-509, respectively) of NECTIN-4 were largely overexpressed in nucleus and cytoplasm, respectively. Endo-domain translocates into nucleus by physically interacting with IMPORTIN-α2, activates the DNA repair and enhances cell growth, whereas ecto-domain specifically activates angiogenesis by modulating representative angiogenic markers, inducing in vitro tube formation and in ovo blood vessel formation. Full-length NECTIN-4 (aa 1-509) was overexpressed in both nucleus and cytoplasm and modulated both DNA repair and angiogenesis. NQC down-regulated these phenomena by modulating the endo-domain and ecto-domain of NECTIN-4. Thus, current study suggested that endo-domain of NECTIN-4 translocated into nucleus and increased the DNA repair and ecto-domain of NECTIN-4 enhanced the angiogenesis, whereas NQC inhibits these processes.

MicroRNA-195 desensitizes HCT116 human colon cancer cells to 5-fluorouracil

Multidrug resistance is one major barrier to successful chemotherapy. Although several studies have attempted to overcome resistance of cancer cells to anti-cancer drugs, key determinants of resistance remain largely unknown. The objective of this study was to investigate whether microRNAs might play a role in the acquisition of resistance. Human colorectal cancer HCT-116 cell lines were transduced with a lentivirus library containing 578 precursor microRNAs (miRNAs) to establish cell lines resistant to 5-fluorouracil (5-FU). Specific miRNAs were identified from four different resistant clones and a miR-195-expressing resistant clone (HCT-116_lenti-miR-195) was further investigated. The HCT-116_lenti-miR-195 cells showed resistant phenotype. These cells grew faster after 5-FU treatment compared to control cells (HCT-116_lenti-control). Check point kinase 1 (CHK1) and G2 check point kinase WEE1 were found to be direct targets of miR-195. Downregulation of miR-195 sensitized HCT-116 cells after 5-FU treatment. Our results demonstrate that miR-195 can promote acquisition of drug resistance to 5-FU.

The Feather Model for Chemo- and Radiation Therapy-Induced Tissue Damage

Chemo- and radiation therapy are the main modalities for cancer treatment. A major limiting factor is their toxicity to normal tissue, thus reducing the dose and duration of the therapy. The hair follicle, gastrointestinal tract, and hematopoietic system are among the target organs that often show side effects in cancer therapy . Although these organs are highly mitotic in common, the molecular mechanism of the damage remains unclear. The feather follicle is a fast-growing mini-organ, which allows observation and manipulation on each follicle individually. As a model system, the feather follicle is advantageous because of the following reasons: (1) its complex structure is regulated by a set of evolutionarily conserved molecular pathways, thus facilitating the effort to dissect the specific signaling events involved; (2) its morphology allows the continuity of normal-perturbed-normal structure in a single feather, thus "recording" the damaging effect of chemo- and radiation therapy; (3) further histological and molecular analysis of the damage response can be performed on each plucked feather; thus, it is not necessary to sacrifice the experimental animal. Here, we describe methods of applying the feather model to study the molecular mechanism of chemo- and radiation therapy-induced tissue damage.