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result(s) for
"Singh, Deepak K."
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A natural antisense lncRNA controls breast cancer progression by promoting tumor suppressor gene mRNA stability
by
Bhargava, Rohit
,
Kim, Tae Gyoon
,
Petracovici, Ana
in
Antisense RNA
,
Apoptosis Regulatory Proteins - antagonists & inhibitors
,
Apoptosis Regulatory Proteins - genetics
2018
The human genome encodes thousands of long noncoding RNA (lncRNA) genes; the function of majority of them is poorly understood. Aberrant expression of a significant number of lncRNAs is observed in various diseases, including cancer. To gain insights into the role of lncRNAs in breast cancer progression, we performed genome-wide transcriptome analyses in an isogenic, triple negative breast cancer (TNBC/basal-like) progression cell lines using a 3D cell culture model. We identified significantly altered expression of 1853 lncRNAs, including ~500 natural antisense transcript (NATs) lncRNAs. A significant number of breast cancer-deregulated NATs displayed co-regulated expression with oncogenic and tumor suppressor protein-coding genes in cis. Further studies on one such NAT, PDCD4-AS1 lncRNA reveal that it positively regulates the expression and activity of the tumor suppressor PDCD4 in mammary epithelial cells. Both PDCD4-AS1 and PDCD4 show reduced expression in TNBC cell lines and in patients, and depletion of PDCD4-AS1 compromised the cellular levels and activity of PDCD4. Further, tumorigenic properties of PDCD4-AS1-depleted TNBC cells were rescued by exogenous expression of PDCD4, implying that PDCD4-AS1 acts upstream of PDCD4. Mechanistically, PDCD4-AS1 stabilizes PDCD4 RNA by forming RNA duplex and controls the interaction between PDCD4 RNA and RNA decay promoting factors such as HuR. Our studies demonstrate crucial roles played by NAT lncRNAs in regulating post-transcriptional gene expression of key oncogenic or tumor suppressor genes, thereby contributing to TNBC progression.
Journal Article
Primary tumor associated macrophages activate programs of invasion and dormancy in disseminating tumor cells
2022
Metastases are initiated by disseminated tumor cells (DTCs) that colonize distant organs. Growing evidence suggests that the microenvironment of the primary tumor primes DTCs for dormant or proliferative fates. However, the manner in which this occurs remains poorly understood. Here, using the Window for High-Resolution Intravital Imaging of the Lung (WHRIL), we study the live lung longitudinally and follow the fate of individual DTCs that spontaneously disseminate from orthotopic breast tumors. We find that spontaneously DTCs have increased levels of retention, increased speed of extravasation, and greater survival after extravasation, compared to experimentally metastasized tumor cells. Detailed analysis reveals that a subset of macrophages within the primary tumor induces a pro-dissemination and pro-dormancy DTC phenotype. Our work provides insight into how specific primary tumor microenvironments prime a subpopulation of cells for expression of proteins associated with dissemination and dormancy.
The understanding of the mechanisms underlying the ability of disseminated tumor cells (DTCs) to form metastasis is incomplete. Here, by using high-resolution intravital imaging of the murine lung to track the fate of breast-derived DTCs, the authors show that macrophages within the primary tumor induce a pro-dissemination and pro-dormancy phenotype in tumor cells, favouring their extravasation in the lung.
Journal Article
Evaluation of volumetric breast density as a risk factor for breast carcinoma in pre- and postmenopausal women, its association with hormone receptor status and breast carcinoma subtypes defined by histology and tumor markers
2022
Mammographic breast density is acknowledged as an independent risk factor for breast cancer. Its association with different pathological types and tumors markers is still under evaluation. This study aims to assess the associations of volumetric density grades (VDG) with breast cancer risk in premenopausal and postmenopausal age groups separately. We also aim to assess the association of VDG with hormone receptor status and breast cancer subtypes defined by histology and tumor markers (ER, PR, Her 2-neu and Ki 67). This retrospective study was done with inclusion of two comparable groups of 185 breast cancer cases and 244 healthy controls. These groups were further divided into preâ and postmenopausal subgroups. Mammograms of the cases and controls were evaluated by fully automated volumetric breast density software-VOLPARA and classified into four VDG. The hormone receptor status and breast cancer subtypes defined by histological features and tumor markers in the various VDG were also evaluated. The risk of developing carcinoma was significantly higher in women with high-density breasts (VDG-c + VDG-d) as compared with low-density breasts (VDG-a + VDG-b) in both premenopausal and postmenopausal subgroups. No significant difference was seen in the histopathological characteristics of breast cancer among various VDG. Our study suggests positive association between high VDG and risk of cancer in both premenopausal and postmenopausal group of Indian women. The hormone receptor status and breast cancer subtypes defined by histology and tumor markers did not reveal any relation to the grades of breast density.
Journal Article
Purification, characterization and assessment of stability, reactive oxygen species scavenging and antioxidative potentials of mycosporine-like amino acids (MAAs) isolated from cyanobacteria
by
Singh, Deepak K
,
Pathak, Jainendra
,
Sinha, Rajeshwar P
in
Absorption spectroscopy
,
Amino acids
,
Anabaena
2022
Mycosporine-like amino acids (MAAs) were characterized and their stability and free radical scavenging potentials were investigated in Anabaena sp. HKAR-7 and Fischerella sp. AR-5. UV/VIS absorption spectroscopy, high performance liquid chromatography and electrospray ionization-mass spectrometry showed occurrence of diverse forms of MAAs at retention time (RT) 1.16 (shinorine), 2.18 (mycosporine glycine-310) and 3.14 min (palythinol) with UVλmax 310, 332 and 334 nm respectively, in Fischerella sp. when contrasted with Anabaena sp. (prominent peak at RT 3.21 min (porphyra 334; P-334) with UVλmax 334 nm. MAAs showed dose-dependent in vitro antioxidative and in vivo reactive oxygen species (ROS) scavenging potentials. The MAA P-334 was used against strong allelochemical pyrogallic acid in Anabaena sp. P-334 reducing the negative impacts brought about by ROS, in this way, the malondialdehyde content and unwinding of dsDNA were similarly low. This clarifies the role of MAA P-334 against cell’s ROS under studied stressed conditions.
Journal Article
Multi-Year On-Farm Trial Data on the Performance of Long- and Short-Duration Wheat Varieties against Sowing Dates in the Eastern Indo-Gangetic Plain of India
by
Ajay, Anurag
,
Poonia, Shishpal
,
Singh, Sudhanshu
in
Agricultural production
,
Biomass
,
Crop yields
2023
Sub-optimal wheat productivity in the eastern Indo-Gangetic plain of India can largely be attributed to delayed sowing and the use of short duration varieties. The second week of November is the ideal time for sowing wheat in eastern India, though farmers generally plant later. Late-sowing farmers tend to prefer short-duration varieties, leading to additional yield penalty. To validate the effect of timely sowing and the comparative performance of long- and short-duration varieties, multi-location on-farm trials were conducted continuously over five years starting from 2016–2017. Ten districts were selected to ensure that all the agro-climatic zones of the region were covered. There were five treatments of sowing windows: (T1) 1 to 10 November, (T2) 11–20 November, (T3) 21 to 30 November, (T4) 1–15 December, and (T5) 16–31 December. Varietal performance was compared in T3, T4, and T5, as short-duration varieties are normally sown after 20 November. There is asymmetry in the distribution of samples within treatments and over the years due to the allocation of fields by farmers. Altogether, the trial was conducted at 3735 sites and captured 61 variables, including yield and yield attributing traits. Findings suggested that grain yields of long-duration wheat varieties are better even under late sown scenarios.
Journal Article
Micropropagation of Anacyclus pyrethrum and chemical profiling of the regenerated plants for pellitorine, the active principle
by
Singh, Deepak K
,
Babbar, Shashi B
,
Nirwan, Shradha
in
Acetic acid
,
Benzyladenine
,
Butyric acid
2015
The paper reports the development of a protocol for large-scale micropropagation of Anacyclus pyrethrum, an invaluable medicinal plant, and the presence of pellitorine, the active principle, in leaves and roots of regenerated plants. Three explants—cotyledonary nodes, hypocotyls and cotyledons—were compared for their shoot development/differentiation ability on Murashige and Skoog’s (MS, Physiol Plant 15:473–497, 1962) medium supplemented with 1–10 µM of 6-benzylaminopurine (BAP) or kinetin (Kn). The best response (8.88 ± 0.28 shoots per explant) was elicited from the cotyledonary nodal explants on MS + 2.5 µM Kn. The in vitro regenerated shoots continued to multiply on being sub-cultured on the same medium. Elongated shoots were cultured on MS medium augmented with different concentrations (0.2–15 µM) of 1-naphthalene acetic acid (NAA), indole-3-acetic acid (IAA) or indole-3-butyric acid (IBA) for induction of roots. The media augmented with 5 or 10 µM IAA or 5 µM NAA were the most effective for the initiation and proliferation of roots. The plantlets were successfully transferred to the following three potting mixtures: garden soil, vermiculite and garden soil (1:1), vermiculite, garden soil and perlite (1:1:1). Among these, the maximum number (75 %) of the transferred plants survived in the garden soil. The high performance liquid chromatographic analyses of roots and leaves of the regenerated plants as well as those from the native habitat revealed the presence of pellitorine in all, with the content being higher in the roots than the corresponding leaves. The developed protocol would be of use for production of A. pyrethrum plants throughout the year, and thus could become a perennial source of the herb and its active principle.
Journal Article
A multiattribute utility evaluation of different methods for the detection of enteric protozoa causing diarrhea in AIDS patients
by
Singh, Deepak K
,
Tuli, Lekha
,
Gulati, Anil K
in
Acquired Immunodeficiency Syndrome - complications
,
Acquired Immunodeficiency Syndrome - parasitology
,
AIDS-Related Opportunistic Infections - complications
2010
Background
Enteric protozoa and sporozoa have emerged as important opportunistic parasites and can cause fatal infections in AIDS patients. The line of treatment being different for them necessitates an accurate and prompt identification of these to avoid empirical treatment. In this study which is the first of its kind from India we did a comprehensive evaluation of different techniques, comparing them on the basis of the attributes like yield, cost, time taken, expertise and infrastructure. For the first time combination of Calcoflour White and DAPI, a nuclear stain, were used to identify
Microsporidia
spp. Thus, a diagnostic protocol was devised for rapid, sensitive and cost effective identification of the opportunistic enteric protozoa.
Results
The organisms isolated from the stool samples of the cases (450 HIV patients) were predominantly
Cryptosporidium
spp.,
Microsporidia
spp. and
Cyclospora
spp. Interestingly, the control group (200 relatives of the patients who were HIV negative) showed a high incidence (21%) of
Cryptosporidium
spp. We found a significant increase in the sensitivity of microscopy in detecting
Cryptosporidium
spp. and
Cyclospora
spp. after formol ether concentration. Kinyoun's staining was better compared to Modified safranin staining for
Cryptosporidium
spp. identification. Although ELISA had a sensitivity of 93.25% and specificity of 97% for
Cryptosporidium
spp. detection, we ranked Kinyoun's staining better than ELISA because it is not affordable to most of our patients. For detecting
Cyclospora cayetanensis
, autoflourescence was the easiest and most cost effective method followed by Safranin technique. Combination of Calcoflour White stain and DAPI gave good results for the identification of
Microsporidia
spp. We assessed the above techniques and graded the attributes in the following descending order: cost effectiveness, sensitivity, ease of use and interpretation, time taken for the procedure and batch testing.
Conclusion
Thus, we conclude that a combination of minimum three procedures should be carried out for the screening of stool specimens of HIV positive patients. Kinyoun's staining should be made mandatory for every diarrheal stool sample from HIV patients. Also every laboratory should assign its own value to the attributes and apply Multiattribute utility theory or the Analytical hierarchy process to decide the most appropriate methodology.
Journal Article
Bone marrow NG2+/Nestin+ mesenchymal stem cells drive DTC dormancy via TGF-β2
2021
In the bone marrow (BM) microenvironment, where breast cancer (BC) disseminated tumour cells (DTCs) can remain dormant for decades, NG2
/Nestin
mesenchymal stem cells (MSCs) promote hematopoietic stem cell quiescence. Here, we reveal that periarteriolar BM-resident NG2
/Nestin
MSCs can also instruct BC DTCs to enter dormancy. NG2
/Nestin
MSCs produce TGFβ2 and BMP7 and activate a quiescence pathway dependent on TGFBRIII and BMPRII, which
p38-kinase result in p27 induction. Genetic depletion of MSCs or conditional knock-out of TGFβ2 in MSCs using an NG2-Cre
driver led to bone metastatic outgrowth of otherwise dormant p27
/Ki67
DTCs. Also ER
BC patients without systemic recurrence displayed higher frequency of TGFβ2 and BMP7 detection in the BM. Our results provide a direct proof that HSC dormancy niches control BC DTC dormancy and suggest that aging or extrinsic factors that affect the NG2
/Nestin
MSC niche homeostasis may result in a break from dormancy and BC bone relapse.
Journal Article
Transfacetal Screw Fixation for Subaxial Cervical Spine
by
Nayak, Satish
,
Singh, Arun
,
Singh, Deepak
in
Care and treatment
,
Case studies
,
Health aspects
2022
Background and Introduction: In the modern era of spine surgery for subaxial cervical spine, transfacetal screw fixation has evolved enormously. Transfacetal screw fixation for subaxial cervical spine is a biomechanically effective technique. In this fixation, four cortical surfaces of the facets are purchased by the transfacetal screws.
Objectives: In this video, we demonstrated the surgical technique of posterior transfacetal screw fixation.
Surgical Technique: Transfacetal screw fixation of subaxial cervical spine was done along with posterior decompression. The entry point of transfacetal screw was defined as 1 mm caudal to mid-point of lateral mass, and screws were directed perpendicular to facet joint in the sagittal plane and straight in the coronal plane. Bone chips were placed over decorticated lateral mass after decompression.
Result: Patient had uneventful recovery and maintained good status at follow up.
Conclusion: In subaxial cervical spine, transfacetal screw fixation is a biomechanically effective, rigid, and an inexpensive technique to obtain immediate rigid fixation.
Journal Article
Probing structure–property relationship in chemical vapor deposited hybrid perovskites by pressure and temperature
by
Guha, Suchismita
,
Dahal, Ashutosh
,
Singh, Deepak K.
in
Anomalies
,
Applied and Technical Physics
,
Biomaterials
2021
Chemical vapor deposition (CVD), a low-cost and a scalable deposition technique, allows the growth of methylammonium lead iodide (MAPbI
3
) films without the use of solvents, substantially increasing air stability while also inducing the stable cubic phase at room temperature and at pressures as low as 0.25 GPa. MAPbI
3
thin films were grown by a facile two-step low-pressure vapor deposition process in a single reactor. This method results in films, which are usually in the tetragonal phase (space group:
I4/mcm
) and occasionally in the cubic phase under ambient conditions. High-pressure synchrotron-based X-ray diffraction studies from CVD-grown MAPbI
3
crystallites show that the sample remains in the cubic phase (space group:
Im
3
¯
) between 0.25 and 3.0 GPa. Temperature-dependent transport measurements show sharp anomalies, correlating with the structural changes. The transport measurements from the CVD-grown cubic MAPI
3
film is further compared with a film in the tetragonal phase.
Graphic Abstract
Journal Article