Cancer is one of the leading causes of death worldwide, primarily due to the dearth of efficient therapies that result in long-lasting remission. This is especially true in cases of metastatic cancer where drug resistance causes the disease to recur after treatment. One of the factors contributing to drug resistance, metastasis, and aggressiveness of the cancer is cancer stem cells (CSCs) or tumor-initiating cells. As a result, CSCs have emerged as a potential target for drug development. In the present review, we have examined and highlighted the lncRNAs with their regulatory functions specific to CSCs. Moreover, we have discussed the difficulties and various methods involved in identifying lncRNAs that can play a particular role in regulating and maintaining CSCs. Interestingly, this review only focuses on those lncRNAs with strong functional evidence for CSC specificity and the mechanistic role that allows them to be CSC regulators and be the focus of CSC-specific drug development.

LASP-1 was identified as a protein following mass spectrometric analysis of phosphoproteins consequent to signaling by ErbB2 in SKOV-3 cells. It has been previously identified as an oncogene and is located on chromosomal arm 17q 0.76 Mb centromeric to ErbB2. It is expressed in serous ovarian cancer cell lines as a 40 kDa protein. In SKOV-3 cells, it was phosphorylated and was inhibited by Lapatinib and CP7274714. LASP-1 co-immunoprecipitated with ErbB2 in SKOV-3 cells, suggesting a direct interaction. This interaction and phosphorylation were independent of the kinase activity of ErbB2. Moreover, the binding of LASP-1 to ErbB2 was independent of the tyrosine phosphorylation of LASP-1. LASP-1 was neither expressed on the surface epithelium of the normal ovary nor in the fallopian tube. It was expressed in 28% of ovarian tumours (n =101) that did not significantly correlate with other clinical factors. In tumours from patients with invasive ductal carcinoma of the breast who had ErbB2 amplification (3+), LASP-1 was expressed in 3/20 (P < 0.001). Analysis of the expression of an independent dataset of ovarian and breast tumours from TCGA showed the significant co-occurrence of ErbB2 and LASP-1 (P < 0.01). These results suggest that LASP-1 and ErbB2 interaction could be important in the pathogenesis of ovarian cancer.

The gene for receptor tyrosine kinase ErbB2 is amplified in breast and ovarian tumours. The linear pathway by which signals are transduced through ErbB2 are well known. However, second generation questions that address spatial aspects of signaling remain. To address this, we have undertaken a mass spectrometry approach to identify phosphoproteins specific for ErbB2 using the inhibitors Lapatinib and CP724714 in ovarian cancer cells. The ErbB2 specific proteins identified in SKOV-3 cells were Myristoylated alanine-rich C-kinase substrate, Protein capicua homolog, Protein peptidyl isomerase G, Protein PRRC2C, Chromobox homolog1 and PRP4 homolog. We have evaluated three phosphoproteins PKM2, Aldose reductase and MARCKS in SKOV-3 cells. We observed that PKM2 was phosphorylated by EGF but was not inhibited by Lapatinib and CP724714. The activity of aldose reductase in reducing NADPH as a substrate was significantly higher in EGF stimulated cells which was inhibited by Lapatinib and CP724714 but not by Geftinib (EGFR inhibitor). MARCKS was phosphorylated on stimulation of SKOV-3 cells with EGF that was inhibited by Lapatinib and CP724714 which was dependent on the kinase activity of ErbB2. These results have identified phosphoproteins that are specific to ErbB2 which have not been previously reported and sets the basis for future experiments.

One of the reasons for recurrence following treatment of high grade serous ovarian carcinoma (HGSOC) is the persistence of residual cancer stem cells (CSCs). There has been variability between laboratories in the identification of CSC markers for HGSOC. We have identified new surface markers (CD24, CD9 and EPHA1) in addition to those previously known (CD44, CD117 and CD133) using a bioinformatics approach. The expression of these surface markers was evaluated in ovarian cancer cell lines, primary malignant cells (PMCs), normal ovary and HGSOC. There was no preferential expression of any of the markers or a combination. All the markers were expressed at variable levels in ovarian cancer cell lines and PMCs. Only CD117 and CD9 were expressed in the normal ovarian surface epithelium and fallopian tube. Both ALDEFLUOR (ALDH1A1) and side population assays identified a small proportion of cells (< 3%) separately that did not overlap with little variability in cell lines and PMCs. All surface markers were co-expressed in ALDH1A1+ cells without preference for one combination. The cell cycle analysis of ALDH1A1+ cells alone revealed that majority of them reside in G0/G1 phase of cell cycle. Further separation of G0 and G1 phases showed that ALDH1A1+ cells reside in G1 phase of the cell cycle. Xenograft assays showed that the combinations of ALDH1A1 + cells co-expressing CD9, CD24 or EPHA1 were more tumorigenic and aggressive with respect to ALDH1A1-cells. These data suggest that a combined approach could be more useful in identifying CSCs in HGSOC.

Transcription factors NANOG, OCT4, SOX2, and NESTIN are expressed in both human embryonic stem cells (hESCs) and cancer stem cells and they play a crucial role in maintaining characteristics of stemness such as self-renewal and pluripotency. This article evaluates the expression of variants of the main stem cell-specific transcription factors NANOG and OCT4 critically and accurately with specific primers designed for identifying the most important variants that maintain stemness. We have examined four variants of NANOG along with a processed pseudogene and seven variants of OCT4 in human teratocarcinoma cell lines (NTERA2D1, SuSa, GCT-27, and 833KE), hESCs, and ovarian cancer cells by reverse transcriptase-polymerase chain reaction. In addition, we have examined their expression in NTERA2D1 cells on differentiation with all-trans-retinoic-acid. We show that NANOG1 is expressed in all teratocarcinoma cells and can be distinguished from NANOGP8, which is an expressed pseudogene. NANOG2 was not expressed in any of the cell lines, including ESCs. OCT4A was expressed in all cells, whereas the variant OCT4B-variant 3 was expressed only in NTERA2D1 cells. On differentiation of NTERA2D1 with retinoic acid, only NANOGP8 and OCT4A were expressed. In ovarian cancer cells, only 3/6 expressed NANOG1 and OCT4A. All malignant cells from patients with ovarian cancer (N = 6) expressed NANOG1 and OCT4A. These results demonstrate the necessity to precisely evaluate the expression of stem cell transcription factors when defining stemness.

Induced pluripotent stem cells are derived from adult somatic cells by ectopic expression of stem cell factors OCT4, SOX2, MYC and KLF4. These cells have characteristic features similar to embryonic stem cells. Although there exists in vitro and in vivo models of cancer, recapitulating the earliest events in the pathogenesis remain challenging. More recently, induced pluripotent stem cells have been generated to model human disease and cancer. There are advantages in the cancer models derived from these cells as compared to existing conventional approaches. Induced pluripotent stem cells have been generated from cancer cell lines, primary tumours and from those with an inherited predisposition to develop cancer. In addition, these cells provide a valuable tool in understanding the pathogenesis of familial cancer in its earliest stages, and to identify additional genetic alterations that are required to develop cancer. Furthermore, these cells can serve as a resource in drug screening and developing new therapies.

Age related macular degeneration is a blinding disease common in elder adults. The prevalence of age related macular degeneration has been found to be 1.8% in the Indian population. Organophosphates are widely used insecticides with well documented neurological effects, and the persistent nature of these compounds in the body results in long term health effects. Farmers exposed to organophosphorus pesticides in USA had an earlier onset of age related macular degeneration when compared to unexposed controls. A recent study found significant levels of an organophosphate, termed chlorpyrifos, in the blood samples of Indian farmers. Therefore, in understanding the link between age related macular degeneration and chlorpyrifos, the need for investigation is important. Our data show that ARPE-19 (retinal pigment epithelial cells) exhibit a cytoprotective response to chlorpyrifos as measured by viability, mitochondrial membrane potential, superoxide dismutase activity, and increased levels of glutathione peroxidase and reduced glutathione, after 24 h exposure to chlorpyrifos. However, this cytoprotective response was absent in ARPE-19 cells exposed to the same range of concentrations of chlorpyrifos for 48 h. These results have physiological significance, since HPLC analysis showed that effects of chlorpyrifos were mediated through its entry into ARPE-19 cells. HPLC analysis also showed that chlorpyrifos remained stable, as we recovered up to 80% of the chlorpyrifos added to 6 different ocular tissues.

The focus of this study was to evaluate the growth of the cells on a scaffold based on novel polyhydroxyalkanoate (PHA) (Polyhydroxy propionate copoly hydroxy ocatadecanoate copolymer), derived from a mutant strain of Pseudomonas sp. Naive PHA was also blended with several biodegradable polymeric materials (PEG, PLA, and MMT) to improve the scaffold properties. Protein adsorption study was done to evaluate the capability of scaffolds for cellular interaction. PHA:PEG blended scaffold showed better adsorption than others. 3T3 fibroblast cultures on various polymers were equally viable when compared with control culture except for the blend PHA:MMT by CCK 8 kit. MTT assay, performed with the continuous cultures HeLa, HEp-2, Vero, and McCoy on the polymer blends, supported the above finding. Among the blends PHA:PEG showed increased viability and was selected for further studies. Cell proliferation assay with colorimetric BrdU ELISA kit showed increase in cell proliferation over the matrix PHA:PEG than that of control. There were no observable morphological changes of continuous cells grown over matrix PHA:PEG when observed by phase contrast microscopy. HEp-2 cells were enclosed within the matrix when analyzed by SEM. The current study states that the scaffold prepared by using the indigenous PHA in combination with PEG supports cell growth better than the conventional plastic surface. PHA:PEG would be a promising material for tissue engineering.