Biology subjects

Kapoor, A.

Publications and source records attributed to Kapoor, A..

35 records · Page 2Linked to original sources

bioRxiv2024

Overcoming brain-derived therapeutic resistance in HER2+ breast cancer brain metastasis

Brain metastasis of HER2+ breast cancer occurs in about 50% of all women with metastatic HER2+ breast cancer and confers poor prognosis for patients. Despite effective HER2-targeted treatments of peripheral HER2+ breast cancer with Trastuzumab +/-HER2 inhibitors, limited brain permeability renders these treatments inefficient for HER2+ breast cancer brain metastasis (BCBM). The scarcity of suitable patient-derived in-vivo models for HER2+ BCBM has compromised the study of molecular mechanisms that promote growth and therapeutic resistance in brain metastasis. We have generated and characterized new HER2+ BCBM cells (BCBM94) isolated from a patient HER2+ brain metastasis. Repeated hematogenic xenografting of BCBM94 consistently generated BCBM in mice. The clinically used receptor tyrosine kinase inhibitor (RTKi) Lapatinib blocked phosphorylation of all ErbB1-4 receptors and induced the intrinsic apoptosis pathway in BCBM94. Neuregulin-1 (NRG1), a ligand for ErbB3 and ErbB4 that is abundantly expressed in the brain, was able to rescue Lapatinib-induced apoptosis and clonogenic ability in BCBM94 and in HER2+ BT474. ErbB3 was essential to mediate the NRG1-induced survival pathway that involved PI3K-AKT signalling and the phosphorylation of BAD at serine 136 to prevent apoptosis. High throughput RTKi screening identified the brain penetrable Poziotinib as highly potent compound to reduce cell viability in HER2+ BCBM in the presence of NRG1. Successful in-vivo ablation of BCBM94- and BT474-derived HER2+ brain tumors was achieved upon two weeks of treatment with Poziotinib. MRI revealed BCBM remission upon poziotinib, but not with Lapatinib treatment. In conclusion, we have established a new patient-derived HER2+ BCBM in-vivo model and identified Poziotinib as highly efficacious RTKi with excellent brain penetrability that abrogated HER2+ BCBM brain tumors in our mouse models.

cancer biology↗

bioRxiv2023

Transcriptional regulation of Dyskerin via canonical WNT signaling modulates sphingolipid biosynthesis and drives colorectal cancer.

Targeting EGFR has been effective in RAS/RAF wild-type colorectal cancer (CRC) patients. However, residual tumor relapses, necessitating the importance of biomarker-guided novel therapeutics. We show elevated DKC1 in [~]88% of CRC patients with poor recurrence-free survival. Clinically, DKC1-positive patients exhibit similarity with CMS2 class, the canonical subtype with active WNT signaling. We show functional significance of DKC1 in cell proliferation, stemness, DNA repair, and survival. Further, mice bearing DKC1 knockdown xenografts show [~]81% reduction in tumor burden. Mechanistically, WNT/{beta}-catenin signaling orchestrates DKC1 expression, then, DKC1/SOX2 complex regulates SGPP2, modulating sphingolipids metabolism. Downregulation of DKC1 in CRC lead to reduced SGPP2 levels leading to dysregulation of sphingolipid biosynthesis. Of note, DKC1-high CRC patients show accumulation of ceramides, namely C23 and C24, signifying their utility in diagnosis. Collectively, we delineate the mechanistic circuitry involved in DKC1-mediated CRC progression, propose ceramides as biomarker, and underscore WNT-based therapeutics for DKC1-positive patients.

cancer biology↗

bioRxiv2023

Validation of a Commercial Radioimmunoassay for Measurement of Human Peripheral Oxytocin

Oxytocin (OT) is a peptide hormone synthesized in the hypothalamus and released into systemic circulation or other areas of the brain. It has a variety of physiological roles such as stimulation of uterine contractions, involvement in social behaviors, and regulation of mood. Its small size and low levels within biological matrices make it challenging to accurately measure. The goal of this study was to demonstrate the specificity of the antibody, sensitivity, and reproducibility of the Phoenix Pharmaceuticals (PP) OT radioimmunoassay (RIA) for use in human urine, serum, and saliva. Specificity of the antibody was assessed by high pressure liquid chromatography with ultraviolet (HPLC-UV) separation and assay of the fractions. Immunoreactivity was evaluated using the percent OT bound, and the fraction retention times were compared to the retention time of an intact OT standard to determine which fractions contained OT in the extracted samples. Reproducibility was assessed by running replicates of pools of each biomatrix over several assays. Sensitivity was assessed by repeated measurement of physiologically relevant low-concentration specimens. In all tested specimens the greatest reactivity in assay corresponded to the same fraction(s) as the OT standard. Only minimal reactivity was found in the other fractions, suggesting that in an unfractionated sample the antibody reacts mostly with intact OT. Reproducibility was acceptable for all specimens and the coefficient of variation (CV) ranged from 3.72-8.04% and 5.89-12.8%, for intra and inter-assay, respectively. The limits of quantitation (LOQ) were sufficient for measurement of normal values in urine (0.643 & 1.43 pg/mL), serum (1.90 pg/mL), and saliva pools (0.485 & 4.42 pg/mL). In conclusion, the PP OT RIA is specific and sensitive enough for reproducible measurement of intact OT in human peripheral biological matrices. HIGHLIGHTSO_LIThe oxytocin radioimmunoassay kit from Phoenix Pharmaceuticals is specific for intact oxytocin measured in human urine, serum, and saliva. C_LIO_LIBasal levels of oxytocin are low in peripheral biomatrices, and the sensitivity of the assay is sufficient for reproducible measurement. C_LI

neuroscience↗

bioRxiv2022

Cardiac muscle-restricted partial loss of Nos1ap expression has limited impact on electro- and echo-cardiographic features

Genome-wide association studies (GWAS) of QT interval variation have identified common noncoding variants at the NOS1AP gene as the most common genetic regulators of trait variation in the general population. Invoking a cis-regulatory mechanistic hypothesis, we have reported identification of a functional enhancer variant underlying the GWAS signal that influenced human cardiac NOS1AP expression. Functional studies based on in vitro overexpression in murine cardiomyocytes and ex vivo knockdown in zebrafish embryonic hearts, by us and others, have demonstrated that NOS1AP expression levels can alter cellular electrophysiology. Here, to explore the role of NOS1AP in cardiac electrophysiology at an organismal level, we generated and characterized constitutive and heart muscle-restricted Nos1ap knockout mice to assess whether NOS1AP disruption alters the QT interval in vivo. Constitutive loss of Nos1ap led to genetic background-dependent variable lethality at or right before birth. Heart muscle-restricted Nos1ap knockouts generated using cardiac specific alpha-myosin heavy chain promoter-driven tamoxifen-inducible Cre resulted in tissue-level Nos1ap expression reduced by half. This partial loss of expression had no detectable effect on the QT interval, but led to a small yet significant reduction in the QRS interval. Given that challenges associated with defining the end of T wave on murine electrocardiogram can limit identification of subtle effects on QT interval, and that common noncoding NOS1AP variants are also associated with QRS interval, our findings support the role of NOS1AP in regulation of the cardiac electrical cycle.

genetics↗

bioRxiv2022

Suboptimal foraging decisions and involvement of the ventral tegmental area in human opioid addiction

Addiction is marked by a tendency to exploit sources of reward despite diminishing returns. This behavior is aptly captured by animal patch-foraging models that have recently been extended to humans. Dopamine and norepinephrine centrally mediate addictive behavior and activity in both catecholaminergic systems is proposed to reflect the computations necessary for optimal foraging. However, the specific neural bases of excessive foraging and their role in human addiction are largely unknown. To address this gap, we studied the behavior of people with and without opioid use disorder (OUD) on a patch-foraging task in which they made serial decisions to "harvest" a depleting resource ("patch") for reward or incur a varying cost to "travel" to a replenished patch. In a subset of participants, we used high-resolution neuromelanin-sensitive MRI to image neuromelanin concentration, a proxy for long-term catecholaminergic function, in distinct dopaminergic nuclei (ventral tegmental area, substantia nigra subregions) and the noradrenergic locus coeruleus. While all participants were sensitive to the long-run reward rates of different patch-foraging environments, OUD participants stayed in reward patches longer than optimal--markedly overharvesting a source of reward despite its declining value--and this correlated with more chronic drug use. Overharvesting was selectively associated with lower neuromelanin signal in the ventral tegmental area but not other dopaminergic nuclei, nor the locus coeruleus. Our findings suggest that foraging decisions relevant to addiction involve a ventral-tegmental-area circuit that may signal reward rates in dynamic environments and implicate this circuit in maladaptive reward pursuit in human addiction to opioids. Significance statementPatch-foraging provides a potentially important translational framework for understanding addictive behavior by revealing how maladaptive reward pursuit emerges in more ecologically valid decision contexts. Here, we show that the tendency to exploit sources of reward despite diminishing returns is associated with chronic drug use in people with opioid use disorder, a particularly devastating form of addiction. We further use neuromelanin-sensitive MRI, a neuroimaging measure of the long-term function of dopamine neurons, to reveal that variation in ventral tegmental area neuromelanin signal selectively underlies individual differences in this overharvesting bias. These findings establish a role for specific dopaminergic circuits in patch-foraging decisions and advance understanding of the neurobiology of human addiction to opioids that has so far eluded the field.

neuroscience↗

bioRxiv2021

A Comparison of Macaque Hair Hormone Concentration Following Enhanced Cognitive Experiences or Standard Nonhuman Primate Environmental Enrichment

Experience with enriched environments positively impacts the health and wellbeing of nonhuman animals ranging from rodents to primates. Little is known, however, about the specific effects of enhanced cognitive enrichment (ECE) on nonhuman primates. The study reported here used archival samples to provide preliminary analysis of ECE on hormones associated with stress and wellbeing, as well as evaluation of persistent effects of infant social rearing. Hair samples from 24 adult male rhesus macaques were analyzed via LC-MS/MS technique for the main stress response hormones: cortisol, cortisone, and dehydroepiandrosterone. The ECE and care-as-usual (CAU) groups did not significantly differ in any of the mean analyte values. Cortisol and dehydroepiandrosterone were strongly and positively correlated in the ECE group. By contrast, for the CAU group the two analytes were weakly correlated. Within the ECE group, cortisol and dehydroepiandrosterone were significantly and positively correlated in the mother-reared group, but not in the nursery-reared group. Overall, these results provide preliminary evidence that experience with ECE could help to maintain a balanced cortisol:dehydroepiandrosterone ratio, possibly indicative of a healthy stress response. Further examination of this ratio in hair is needed to support this hypothesis. These observations may also suggest that nursery rearing could have persistent effects, including dysregulation of the hypothalamic-pituitary-adrenal axis, apparent in the unbalanced cortisol:dehydroepiandrosterone ratio. Together these findings are consistent with the growing literature that supports the use of ECE to promote nonhuman primate wellbeing and healthy development.

zoology↗

bioRxiv2021

Development and Validation of an LC-MS/MS Based Quantitative Assay for Marmoset Insulin

IntroductionInsulin is a peptide hormone that is secreted by the {beta} cells of the pancreas and is essential to the metabolism of carbohydrates, fats, and proteins in the body. The marmoset insulin peptide is not homologous with human insulin and therefore commonly available assays do not work for this species. Due to the increasing popularity of marmoset research, a simple, specific assay for the quantitation of marmoset insulin is needed. This study aimed to develop and validate a bottom-up proteomic workflow with trypsin digestion and analysis using LC coupled with triple quadrupole mass spectrometry (LC-MS/MS). MethodsMarmoset serum proteins were subjected to denaturation, reduction, and enzymatic cleavage to extract a unique, 7 amino acid peptide for quantitation of marmoset insulin.Resolution of the peptide was achieved by LC-MS/MS using electrospray ionization operating in positive mode. Calibration was achieved by aliquot dilution of fully synthetic marmoset insulin tryptic peptide into macaque serum. A stable-isotope labeled (13C, 15N) synthetic marmoset insulin tryptic peptide was used as internal standard. ResultsThe assay was fully validated according to bioanalytical method validation guidelines for linearity, precision, and dilution linearity using purified marmoset insulin. The limit of detection was 4.28 pmol/L and the limit of quantitation was 8.62 pmol/L. Biological validation was achieved by comparison of samples previously run by radioimmunoassay and measurement of the marmoset insulin response to glucose via an oral glucose tolerance test (OGTT). The physiological range of marmoset insulin was shown to be 84.5 to 1222 pmol/L. ConclusionsThis paper presents a simple, reproducible method to measure marmoset insulin using LC-MS/MS.

biochemistry↗

bioRxiv2021

A Promising Chemical Series of Positive Allosteric Modulators of the μ-Opioid Receptor that Enhance the Antinociceptive Efficacy of Opioids but not their Adverse Effects

Positive allosteric modulators (PAMs) of the {micro}-opioid receptor (MOR) have been proposed to exhibit therapeutic potential by maximizing the analgesic properties of clinically used opioid drugs while limiting their adverse effects or risk of overdose as a result of using lower drug doses. We herein report in vitro and in vivo characterization of two small molecules from a chemical series of MOR PAMs that exhibit: (i) MOR PAM activity and receptor subtype selectivity in vitro, (ii) a differential potentiation of the antinociceptive effect of oxycodone, morphine, and methadone in mouse models of pain that roughly correlates with in vitro activity, and (iii) a lack of potentiation of adverse effects associated with opioid administration, such as somatic withdrawal, respiratory depression, and analgesic tolerance. This series of MOR PAMs holds promise for the development of adjuncts to opioid therapy to mitigate against overdose and opioid use disorders.

neuroscience↗

bioRxiv2021

Sequence-based correction of barcode bias in massively parallel reporter assays

Massively parallel reporter assays (MPRA) are a high-throughput method for evaluating in vitro activities of thousands of candidate cis-regulatory elements (CREs). In these assays, candidate sequences are cloned upstream or downstream of a reporter gene tagged by unique DNA sequences. However, tag sequences may themselves affect reporter gene expression and lead to major potential biases in the measured cis-regulatory activity. Here, we present a sequence-based method for correcting tag sequence-specific effects and demonstrate that our method can significantly reduce this source of variation, and improve the identification of functional regulatory variants by MPRAs. We also show that our model captures sequence features associated with post-transcriptional regulation of mRNA. Thus, this new method helps to not only improve detection of regulatory signals in MPRA experiments but also to design better MPRA protocols.

bioinformatics↗

bioRxiv2021

Dual control exerted by dopamine in blood-progenitor cell cycle regulation in Drosophila

In Drosophila, definitive hematopoiesis occurs in a specialized organ termed "lymph gland", where multi-potent stem-like blood progenitor cells reside and their homeostasis is central to growth of this organ. Recent findings have implicated a reliance on neurotransmitters in progenitor development and function however, our understanding of these molecules is still limited. Here, we extend our analysis and show that blood-progenitors are self-sufficient in synthesizing dopamine, a well-established neurotransmitter and have modules for its sensing through receptor and uptake via, transporter. Modulating their expression in progenitor cells affects lymph gland growth. Progenitor cell cycle analysis revealed an unexpected requirement for intracellular dopamine in the progression of early progenitors from S to G2 phase of the cell cycle, while activation of dopamine-receptor later in development regulated progression from G2 to entry into mitosis. The dual capacity in which dopamine operates, both intra-cellular and extra-cellular, controls lymph gland growth. These data highlight a novel and non-canonical use of dopamine as a proliferative cue by the myeloid-progenitor system and reveals a functional requirement for intracellular dopamine in cell-cycle progression.

developmental biology↗

bioRxiv2020

Pubertal androgens reduce the effects of social stress on anxiety-related behaviors in California mice

Anxiety disorders are more common in women than men, and this difference arises during puberty. Increased secretion of gonadal hormones during puberty influences brain structure and function, but the extent to which hormones modulate anxiety-related brain circuits is unclear. The slow developing California mouse (Peromyscus californicus) is an ideal species for studying the effects of hormones on brain function during adolescence. In adults social defeat stress reduces social approach and increases vigilance in females but not males. Here we show this sex difference is absent in juvenile mice, and that prepubertal castration sensitizes adult males to social defeat. Since adult castration has no effect on stress sensitivity, our data show that gonadal hormones act during puberty to program behavioral responses to stress later in life. In adults, calcium imaging in the medioventral bed nucleus of the stria terminalis shows that threatening social contexts increase calcium transients. Furthermore, prepubertal castration generalizes these responses to less threatening social contexts. Prepubertal treatment with the non-aromatizable androgen dihydrotestosterone acts in males and females to reduce sensitivity to social defeat in adults. Together, these data indicate activation of androgen receptors during puberty are critical for programing behavioral responses to stress in adulthood, highlighting a possible mechanism contributing to sex differences in anxiety. Significance StatementPuberty is a key period when sex differences in anxiety emerges. Gonadal hormone release increases during this time but it is largely unknown how they impact brain circuits and behavior. We show that androgens play a key role in programming behavioral responses to social defeat stress. The bed nucleus of the stria terminalis responds to social threats and these responses are more generalized in males without gonadal hormone exposure during puberty. Our findings highlight the importance of pubertal androgens in determining adult behavioral responses to social stress.

developmental biology↗

bioRxiv2020

A multi-enhancer RET regulatory code is disrupted in Hirschsprung disease

The major genetic risk factors for Hirschsprung disease (HSCR) are three common polymorphisms within cis regulatory elements (CREs) of the RET receptor tyrosine kinase gene that reduce its gene expression during enteric nervous system (ENS) development. These variants have synergistic effects on RET gene expression and additionally dysregulate other ENS and HSCR genes in the RET-EDNRB gene regulatory network (GRN). Here, we use siRNA, ChIP and CRISPR/Cas9 deletion analyses in the SK-N-SH cell line to ask, how many HSCR-associated risk variants reside in CREs and affect RET gene expression? We demonstrate that 31 HSCR-associated variants reside in candidate RET CREs, ten with differential allele-specific in vitro enhancer activity and seven affecting RET gene expression; of these, five bind the transcription factors PAX3, RARB, GATA2 and SOX10. These and our prior results demonstrate that common sequence variants in at least 10 RET enhancers affect HSCR risk, extending the known RET-EDNRB GRN to reveal an extensive regulatory code modulating disease risk even at a single gene.

genomics↗

bioRxiv2020

Multiple, independent, common variants overlapping known and putative gut enhancers at RET, SEMA3 and NRG1 underlie Hirschsprung disease risk in European ancestry subjects

PurposeHirschsprung disease (HSCR) is a developmental disorder of the enteric nervous system (ENS) characterized by congenital aganglionosis, and where individual cases harbor coding risk variants in ENS genes. Low-penetrance, common, noncoding variants at RET, SEMA3 and NRG1 loci have been associated in HSCR as well, implicating variable gene expression mediated by cis-regulatory element (CRE) variants as the causal mechanism. However, the extent and combinatorial effects of all putative CRE variants within and across these loci on HSCR is unknown. MethodsUsing 583 HSCR subjects, one of the largest samples of European ancestry studied, and genotyping 56 tag variants we evaluated association of all common variants overlapping putative gut CREs and fine-mapped variants at RET, SEMA3 and NRG1. ResultsWe demonstrate that 28 and 8 tag variants, several of which are independent, overlapping putative-enhancers at the RET and SEMA3 loci, respectively, and, 2 fine-mapped tag variants at NRG1 locus, are associated with HSCR. We demonstrate that risk increases with increasing risk allele dosage from multiple variants within and across these loci and varies >25- fold. ConclusionGene regulatory networks in HSCR-relevant cell types quantify the total burden of risk alleles through sensing reduced gene expression of multiple genes on disease.

genetics↗

bioRxiv2020

High-resolution Structures of multiple 5-HT3AR-setron complexes reveal a novel mechanism of competitive inhibition

Serotonin receptors (5-HT3AR) play a crucial role in regulating gut movement, and are the principal target of setrons, a class of high-affinity competitive antagonists, used in the management of nausea and vomiting associated with radiation and chemotherapies. Structural insights into setron-binding poses and their inhibitory mechanisms are just beginning to emerge. Here, we present high-resolution cryo-EM structures of full-length 5-HT3AR in complex with palonosetron, ondansetron, and alosetron. Each structure reveals a distinct interaction fingerprint between the setron and binding-pocket residues that may underlie their diverse affinities. In addition, setrons elicit varying degrees of conformational change throughout the channel that, quite surprisingly, lie along the channel activation pathway, suggesting a novel mechanism of competitive inhibition. Molecular dynamic simulations were used to assess binding-poses and the drug-target interaction dynamics. Together, this study provides a molecular basis for setron binding affinities and their inhibitory effects.

biophysics↗

bioRxiv2019

Human Rotavirus Diarrhea Is Associated with Altered Trafficking and Expression of Apical Membrane Transport Proteins

BackgroundRotavirus (RV) is the 5th leading cause of death in children <5 years old but the leading cause of diarrhea related deaths in this age group. The mechanism of RV diarrhea involves decreased activity of Na+-dependent solute transporters with increased luminal secretion of Cl- in the absence of significant histologic damage. While our understanding of RV diarrhea has come from studies in animal models and cancer cell lines, the mechanism of the diarrhea and the transport proteins affected in human RV disease remains only partially understood. This understanding is likely to impact drug development therapy for RV diarrhea.\n\nMethodsFormalin-fixed paraffin-embedded small intestinal specimens from patients diagnosed with RV diarrhea (confirmed by anti-RV antibodies) were analyzed by immunofluorescence for changes in apical/basolateral ion/nutrient transporters/channels as well as tight junctional and cytoskeletal proteins. Proximal small intestinal enteroids generated from biopsies obtained from healthy human subjects were grown as monolayers, differentiated to resemble villus epithelial cells, and infected with human RV.\n\nResultsRV diarrhea was associated with reduced expression and intracellular localization of transport proteins normally found in the brush border membranes, including SGLT1, NHE3, NHE2, the Na+-dependent amino acid transporter SLC6A19, and CFTR. In contrast, basolateral proteins, including Na+/K+-ATPase, NKCC1, and {beta}-catenin, the brush border marker ezrin, as well as the tight junction protein, ZO-1, were expressed and localized normally. RV-induced mislocalization of NHE3, SGLT1, SLC6A19 and CFTR was also seen when human small intestinal enteroids were infected with RV.\n\nConclusionsThese data demonstrate a new pathophysiologic mechanism of acute diarrhea in which expression of multiple apical transport proteins are reduced. This acute diarrhea is likely to be caused by an effect on a common apical trafficking pathway, as exemplified by RV diarrhea, and its contribution to other enteric pathogen-induced diarrheal diseases should be determined.

cell biology↗

bioRxiv2019

Metabolic control of immune-competency by odors in Drosophila

Drosophila blood-progenitor cells generate an inflammatory cell-type termed lamellocyte, in response to parasitic wasp-infections. In this study we show that olfaction primes lamellocyte potential. Specifically, larval odor-detection mediated release of systemic {gamma}-aminobutyric acid (GABA) from neurosecretory cells, is detected and internalized by blood progenitor-cells. GABA catabolism through the GABA-shunt pathway prevents Sima (HIF) protein degradation. Sima is necessary and sufficient for lamellocyte induction. However, limited systemic GABA availability during development restricts blood-progenitor Sima levels and consequently their lamellocyte potential. Preconditioning Drosophila larvae in odor environments mimicking parasitoid-threatened conditions raises systemic GABA and blood-progenitor Sima levels. As a result, infection responses in these animals are rapid and efficient. Overall, this study explores the importance of sensory control of myeloid-immunity and unravels the adaptive influence of environmental odor-experience on myeloid-metabolism and priming innate-immune potential.

developmental biology↗

bioRxiv2017

Soft drug-resistant ovarian cancer cells invade via two distinct mechanisms utilizing myosin IIB

The failure of chemotherapeutic drugs in treatment of various cancers is attributed to the acquisition of drug resistance. However, the invasion mechanisms of drug-resistant cancer cells remains incompletely understood. Here we address this question from a biophysical perspective by mapping the phenotypic alterations in ovarian cancer cells (OCCs) resistant to cisplatin and paclitaxel. We show that cisplatin-resistant (CisR), paclitaxel-resistant (PacR) and dual drug-resistant (i.e., resistant to both drugs) OCCs are softer and more contractile than drug-sensitive cells. Protease inhibition suppresses invasion of CisR cells but not of PacR and dual cells, suggesting protease-dependent mode of invasion in CisR cells and protease-independent mode in PacR and dual cells. Despite these differences, actomyosin contractility, mediated by the RhoA-ROCK2-Myosin IIB signaling pathway regulates both modes of invasion. Myosin IIB modulates matrix metalloproteinase-9 (MMP-9) secretion in CisR cells and nuclear squeezing in PacR and dual cells, thereby highlighting its importance as a potential therapeutic target for treatment of drug-resistant ovarian cancer cells.\n\nFinancial SupportAuthors acknowledge financial support from IIT Bombay Healthcare Initiative, CSIR andDepartment of Biotechnology (Govt. of India) (Grant # BT/PR14658/MED/31/107/2010).AK and BTwere supported by fellowships from UGC and CSIR respectively (Govt. of India).\n\nAuthors declare no competing financial interests\n\nAuthor contributions: AK, PR and SS designed the experiments. AK performed most of the experiments and analyzed the data.BT and SG developed drug resistant cell lines and did RT-PCR. MM performed western blot. AD performed AFM experiments. SD performed gelatin zymography. ABB, PM, AM and AD helped with live cell imaging experiments. AK and SS wrote the manuscript. All authors read and approved the final manuscript.\n\nSummary statement: This study identifies drug-specific differences in the modes of invasion utilized by ovarian cancer cells, and demonstrates the role of myosin IIB in regulating both modes of invasion.

biophysics↗