Biology subjects

Sikandar, S.

Publications and source records attributed to Sikandar, S..

12 recordsLinked to original sources

bioRxiv2026

BCL11B predetermines a persister state in breast cancer that is reversed by TNFα

The frequent development of chemoresistance in cancer presents a significant clinical challenge, yet the underlying causes for heterogeneous drug responses remain largely elusive. Here, we systematically assessed the cellular differentiation status of human breast cancer cells utilizing single-cell atlases and identified a distinct population of immature basal-like cancer cells marked by BCL11B. Notably, higher levels of BCL11B+ cancer cells are significantly associated with early relapse in breast cancer patients who received chemotherapy. Functioning as a central regulator, BCL11B delineates an immature cell state that preferentially transitions to a drug-resistant persister state during treatment through multiple pre-existing and adaptive drug-resistance programs. Importantly, the cytokine tumor necrosis factor alpha (TNF) is revealed as a natural inhibitor of BCL11B and can directly reverse the emergence of chemoresistant persister cells. Therefore, we identify BCL11B as an unappreciated pre-determinant of drug response and a therapeutic target for a subset of breast cancer patients at high risk of developing chemoresistance.

Cancer Biology↗

bioRxiv2026

Transient silencing of spinal nociceptive neurons leads to a long-term reduction in joint pain mediated by recruitment of opioid activity.

Chronic inflammatory joint pain remains inadequately treated despite current therapies, creating urgent clinical need for non-addictive alternatives in an era of heightened opioid-related concerns. A promising new approach involves conjugates of botulinum toxin and substance P (SP-BOT), which, when infused locally or spinally, have been shown to produce temporary pain relief in neuropathic mouse models, with its effects declining after approximately 100 days as the construct loses activity. However, its long-term efficacy in inflammatory pain models was unknown. Unexpectedly, in a mouse model of ankle inflammatory arthritis, a single intrathecal injection of SP-BOT at the peak of pain sensitivity produced a persistent reduction in mechanical hyperalgesia that lasted for weeks beyond the loss of construct activity. Furthermore, this late-phase pain relief exhibited a striking mechanism in that a single injection of the opioid antagonist naltrexone partially reversed the anti-hyperalgesia generated by SP-BOT. These data indicate that SP-BOT-mediated neuronal silencing initiates two distinct phases of pain relief. An initial, direct phase is followed by a second, sustained phase that maintains pain alleviation and is driven by endogenous opioid mechanisms.

pharmacology and toxicology↗

bioRxiv2025

Paradoxical Phenotype of Fibromyalgia Neutrophils with Elevated Baseline Inflammation but Blunted Response to Stimulation

Fibromyalgia (FM) is a severe pain condition of unknown etiology. Here, we performed transcriptomics analyses of peripheral neutrophils exposed to an inflammatory stimulus, comparing responses of neutrophils obtained from FM patients versus healthy controls. We observed a state of inflammation in neutrophils from FM patients. However, FM neutrophils were unable to efficiently respond to lipopolysaccharide (LPS). This impairment was especially characteristic of FM patients with no improvement after 5 years after diagnosis in comparison with those who did improve. Blood plasma from FM patients directly stimulated a wide range of primary sensory neurons in vitro and induced pain hypersensitivity when injected into mice. Further analysis identified NF-{kappa}B suppression as a key biological process associated with low-grade inflammation and LPS non-responsiveness in neutrophils from FM patients. The clinically used NF-{kappa}B activator, bryostatin, alleviated hypersensitivity in mice treated with FM plasma, pointing to controlled inflammation induction through reactivation of the NF-{kappa}B pathway as a possible therapeutic target for FM treatment. Our whole blood single-cell RNA sequencing replicated this NF-{kappa}B-driven inflammation observed in bulk analyses transcriptomics in FM patients and revealed that this inflammatory signature is strongly pronounced not only in neutrophils, but across a broad range of immune cells.

molecular biology↗

bioRxiv2024

Acute and early stress axis modulation in joint disease permanently reduces pain and emotional comorbidities

Chronic pain affects 20-30% of the population and imposes a significant socio-economic burden as it is often accompanied by substantial emotional comorbidities such as anxiety and depression. Yet, the mechanisms underlying the interactions between the sensory and emotional aspects of chronic pain remain poorly understood. Here, we investigated the role of FKBP51, a regulator of the stress response, in mediating both sensory and emotional symptoms of chronic pain. Inhibition of FKBP51, via genetic deletion or pharmacological blockade, in persistent joint pain reduced fast-onset sensory, functional and activity-related symptoms, as well as late anxio-depressive comorbidities. FKBP51 inhibition after the establishment of the hypersensitive state provided only temporary symptoms relief, while acute inhibition at disease onset protected from the full development of sensory and anxio-depressive symptoms for up to 6 months. Our results also indicated that early pain symptoms could predict the late sensory and emotional outcomes of chronic pain. RNA sequencing of spinal cord tissue revealed that late FKBP51 inhibition transiently altered nociceptive genes associated with mechanical hypersensitivity. In contrast, early inhibition persistently downregulated the Naaa gene, a key regulator of the transition to chronic pain, and reorganized spinal cilia. Our results indicate that early FKBP51 inhibition after injury can persistently reduce chronic pain and prevent the onset of associated emotional comorbidities by modulating critical spinal neurobiological pathways that play pivotal roles in the transition to chronic pain. Significance statementOur study reveals that early inhibition of FKBP51, a modulator in the stress axis, at the onset of joint damage provides sustained pain relief and significantly delays or prevents emotional comorbidities in a sex-dependent manner. In contrast, FKBP51 inhibition initiated after chronic pain is established results in only temporary symptoms improvement. These findings highlight a critical therapeutic window during which timely intervention can prevent the transition from acute to chronic pain. By establishing a predictive link between early therapeutic response and long-term outcomes, this work has important clinical implications for proactive and personalized chronic pain management.

neuroscience↗

bioRxiv2024

U2AF1 S34F enhances tumorigenic potential of lung cells by exhibiting synergy with KRAS mutation and altering response to environmental stress

Although U2AF1S34F is a recurrent splicing factor mutation in lung adenocarcinoma (ADC), U2AF1S34F alone is insufficient for producing tumors in previous models. Because lung ADCs with U2AF1S34F frequently have co-occurring KRAS mutations and smoking histories, we hypothesized that tumor-forming potential arises from U2AF1S34F interacting with oncogenic KRAS and environmental stress. To elucidate the effect of U2AF1S34F co-occurring with a second mutation, we generated human bronchial epithelial cells (HBEC3kt) with co-occurring U2AF1S34F and KRASG12V. Transcriptome analysis revealed that co-occurring U2AF1S34F and KRASG12V differentially impacts inflammatory, cell cycle, and KRAS pathways. Subsequent phenotyping found associated suppressed cytokine production, increased proliferation, anchorage-independent growth, and tumors in mouse xenografts. Additionally, HBEC3kts harboring U2AF1S34F alter splicing in stress granule protein genes, show increased stress granule formation, and have increased viability in cigarette smoke concentrate. Our results suggest that U2AF1S34F may potentiate transformation by granting precancerous cells survival advantage in environmental stress, permitting accumulation of additional mutations, like in KRAS, which synergize with U2AF1S34F to transform the cell.

cancer biology↗

bioRxiv2024

Novel therapies for cancer-induced bone pain

1.Cancer pain is a growing problem, especially with the substantial increase in cancer survival. Reports indicate that bone metastasis, whose primary symptom is bone pain, occurs in 65-75% of patients with advanced breast or prostate cancer. We optimized a preclinical in vivo model of cancer-induced bone pain (CIBP) involving the injection of Lewis Lung Carcinoma cells into the intramedullary space of the femur of C57BL/6 mice or transgenic mice on a C57BL/6 background. Mice gradually reduce the use of the affected limb, leading to altered weight bearing. Symptoms of secondary cutaneous heat sensitivity also manifest themselves. Following optimization, three potential analgesic treatments were assessed; 1) single ion channel targets (targeting the voltage-gated sodium channels NaV1.7, NaV1.8, or acid-sensing ion channels), 2) silencing {micro}-opioid receptor-expressing neurons by modified botulinum compounds, and 3) targeting two inflammatory mediators simultaneously (nerve growth factor (NGF) and tumor necrosis factor (TNF)). Unlike global NaV1.8 knockout mice which do not show any reduction in CIBP-related behavior, embryonic conditional NaV1.7 knockout mice in sensory neurons exhibit a mild reduction in CIBP-linked behavior. Modified botulinum compounds also failed to cause a detectable analgesic effect. In contrast, inhibition of NGF and/or TNF resulted in a significant reduction in CIBP-driven weight-bearing alterations and prevented the development of secondary cutaneous heat hyperalgesia. Our results support the inhibition of these inflammatory mediators; and more strongly their dual inhibition to treat CIBP, given the superiority of combination therapies in extending the time needed to reach limb use score zero in our CIBP model.

neuroscience↗

bioRxiv2023

Chemogenetic silencing of NaV1.8 positive sensory neurons reverses chronic neuropathic and bone cancer pain in FLEx PSAM4-GlyR mice

Drive from peripheral neurons is essential in almost all pain states, but pharmacological silencing of these neurons to effect analgesia has proved problematic. Reversible gene therapy using long-lived chemogenetic approaches is an appealing option. We used the genetically-activated chloride channel PSAM4 -GlyR to examine pain pathways in mice. Using recombinant AAV9-based delivery to sensory neurons, we found a reversal of acute pain behavior and diminished neuronal activity using in vitro and in vivo GCaMP imaging upon activation of PSAM4 -GlyR with varenicline. A significant reduction in inflammatory heat hyperalgesia and oxaliplatin-induced cold allodynia was also observed. Importantly, there was no impairment of motor coordination, but innocuous von Frey sensation was inhibited. We generated a transgenic mouse that expresses a CAG-driven FLExed PSAM4 -GlyR downstream of the Rosa26 locus that requires Cre recombinase to enable the expression of PSAM4 -GlyR and tdTomato. We used NaV1.8 Cre to examine the role of predominantly nociceptive NaV1.8+ neurons in cancer-induced bone pain (CIBP) and neuropathic pain caused by chronic constriction injury (CCI). Varenicline activation of PSAM4 -GlyR in NaV1.8-positive neurons reversed CCI-driven mechanical, thermal, and cold sensitivity. Additionally, varenicline treatment of mice with CIBP expressing PSAM4 -GlyR in NaV1.8+ sensory neurons reversed cancer pain as assessed by weight-bearing. Moreover, when these mice were subjected to acute pain assays, an elevation in withdrawal thresholds to noxious mechanical and thermal stimuli was detected, but innocuous mechanical sensations remained unaffected. These studies confirm the utility of PSAM4 -GlyR chemogenetic silencing in chronic pain states for mechanistic analysis and potential future therapeutic use. Significance statementChronic pain is a massive problem. Peripheral nerve block is effective in many chronic pain conditions, demonstrating the importance of peripheral drive in chronic pain. We used chemogenetic tools based on the modified ligand-gated chloride channel PSAM4 -GlyR to silence dorsal root ganglion neurons in vitro and in vivo. This approach reduces pain-like behavior in acute and chronic pain models, including resistant pain conditions like neuropathic pain or cancer-induced bone pain. We generated a mouse line that expresses PSAM4 -GlyR in a Cre-dependent manner, providing a useful research tool to address not only the role of nociceptive sensory neurons in pain states but also the function of genetically defined sets of neurons throughout the nervous system in normal and pathological conditions.

neuroscience↗

bioRxiv2022

Neutrophils infiltrate sensory ganglia and mediate chronic widespread pain in fibromyalgia

Fibromyalgia is a debilitating widespread chronic pain syndrome that occurs in 2-4% of the population. The prevailing view that fibromyalgia results from central nervous system dysfunction has recently been challenged with data showing changes in peripheral nervous system activity. Using a mouse model of chronic widespread pain through hyperalgesic priming of muscle, we show that neutrophils invade sensory ganglia and confer mechanical hypersensitivity on recipient mice, whilst adoptive transfer of immunoglobulin, serum, lymphocytes or monocytes have no effect on pain behaviour. Neutrophil depletion abolishes the establishment of chronic widespread pain in mice. Neutrophils from patients with fibromyalgia also confer pain on mice. A link between neutrophil derived mediators and peripheral nerve sensitisation is already established. These observations suggest new approaches for targeting fibromyalgia pain through an understanding of the mechanisms that cause altered neutrophil activity and interactions with sensory neurons. Significance statementWe used a back-translational model in mice to demonstrate the pro-nociceptive role of neutrophils in fibromyalgia. Adoptive transfer of neutrophils from mice with chronic widespread pain or from patients with fibromyalgia can confer mechanical pain to recipient naive mice, sensitise evoked action potential firing of spinal cord neurons and produce phenotypic changes in cell surface expression of neutrophil proteins that cause infiltration of neutrophils into dorsal root ganglia. These data provide the framework for an immunological basis of chronic widespread pain in fibromyalgia mediated by polymorphonuclear granulocytes.

neuroscience↗

bioRxiv2020

Sensitization of cutaneous primary afferents in bone cancer revealed by in vivo calcium imaging

Cancer-induced bone pain (CIBP) is a complex condition comprising components of inflammatory and neuropathic processes, but changes in the physiological response profiles of bone-innervating afferents remain poorly understood. We used a combination of retrograde labelling and in vivo calcium imaging of bone marrow-innervating DRG neurons to determine the contribution of these cells in the establishment and maintenance of CIBP. We found a majority of femoral bone afferent cell bodies in L3 DRG that also express the sodium channel subtype Nav1.8 - a marker of nociceptive neurons- and lack expression of parvalbumin - a marker for proprioceptive primary afferents. Surprisingly, the response properties of bone marrow afferents to both increased intraosseous pressure and acid were unchanged by the presence of cancer. On the other hand, we found increased excitability and polymodality of cutaneous afferents innervating the ipsilateral paw in cancer bearing animals, as well as a behavioral phenotype that suggests changes at the level of the DRG contribute to secondary hypersensitivity.

neuroscience↗

bioRxiv2018

Mechanism and resistance for antimycobacterial activity of a fluoroquinophenoxazine compound

We have previously reported the inhibition of bacterial topoisomerase I activity by a fluoroquinophenoxazine compound (FP-11g) with a 6-bipiperidinyl lipophilic side chain that exhibited promising antituberculosis activity (MIC = 2.5 M against Mycobacterium tuberculosis, SI = 9.8). Here, we found that the compound is bactericidal towards Mycobacterium smegmatis, resulting in greater than 5 Log10 reduction in colony-forming units [cfu]/mL following a 10 h incubation at 1.25 M (4X MIC) concentration. Growth inhibition (MIC = 50 M) and reduction in cfu could also be observed against a clinical isolate of Mycobacterium abscessus. Stepwise isolation of resistant mutants of M. smegmatis was conducted to explore the mechanism of resistance. Mutations in the resistant isolates were identified by direct comparison of whole-genome sequencing data from mutant and wild-type isolates. These include mutations in genes likely to affect the entry and retention of the compound. FP-11g inhibits Mtb topoisomerase I and Mtb gyrase with IC50 of 0.24 and 31.5 M, respectively. Biophysical analysis showed that FP-11g binds DNA as an intercalator but the IC50 for inhibition of Mtb topoisomerase I activity is >10 fold lower than the compound concentrations required for producing negatively supercoiled DNA during ligation of nicked circular DNA. Thus, the DNA-binding property of FP-11g may contribute to its antimycobacterial mechanism, but that alone cannot account for the observed inhibition of Mtb topoisomerase I.

microbiology↗

bioRxiv2018

Usp16 modulates Wnt signaling in primary tissues through Cdkn2a regulation

Regulation of the Wnt pathway in stem cells and primary tissues is still poorly understood. Here we report that Usp16, a negative regulator of Bmi1/PRC1 function, modulates the Wnt pathway in mammary epithelia, primary human fibroblasts and MEFs, affecting their expansion and self-renewal potential. In mammary glands, reduced levels of Usp16 increase tissue responsiveness to Wnt, resulting in upregulation of the downstream Wnt target Axin2, expansion of the basal compartment and increased in vitro and in vivo epithelial regeneration. Usp16 regulation of the Wnt pathway in mouse and human tissues is at least in part mediated by activation of Cdkn2a, a regulator of senescence. At the molecular level, Usp16 affects Rspo-mediated phosphorylation of LRP6. In Downs Syndrome (DS), triplication of Usp16 dampens the activation of the Wnt pathway. Usp16 copy number normalization restores normal Wnt activation in Ts65Dn mice models. Genetic upregulation of the Wnt pathway in Ts65Dn mice rescues the proliferation defect observed in mammary epithelial cells. All together, these findings link important stem cell regulators like Bmi1/Usp16 and Cdkn2a to Wnt signaling, and have implications for designing therapies for conditions, like DS, aging or degenerative diseases, where the Wnt pathway is hampered.

cell biology↗

bioRxiv2017

Brain-derived neurotrophic factor derived from peripheral sensory neurons plays a critical role in pain chronification

Multiple studies support the pro-nociceptive role of brain-derived neurotrophin factor (BDNF) in pain processes in the peripheral and central nervous system. We have previously shown that nociceptor-derived BDNF is implicated in inflammatory pain. Microglial-derived BDNF has also been shown to be involved in neuropathic pain. However, the distinct contribution of primary afferent-derived BNDF to chronic pain processing remains undetermined. In this study, we used Advillin-CreERT2 mice to delete Bdnf from all adult peripheral sensory neurons. Conditional BDNF knockouts were healthy with no sensory neuron loss. Behavioural assays and in vivo electrophysiology indicated that spinal excitability was normal. Following formalin inflammation or neuropathy with a modified Chung model, we observed normal development of acute pain behaviour, but a deficit in second phase formalin-induced nocifensive responses and a reversal of neuropathy-induced mechanical hypersensitivity during the later chronic pain phase in conditional BDNF knockout mice. In contrast, we observed normal development of acute and chronic neuropathic pain in the Seltzer model, indicating differences in the contribution of BDNF to distinct models of neuropathy. We further used a model of hyperalgesic priming to examine the contribution of primary afferent-derived BDNF in the transition from acute to chronic pain, and found that primed BDNF knockout mice do not develop prolonged mechanical hypersensitivity. Our data suggest that BDNF derived from sensory neurons plays a critical role in mediating the transition from acute to chronic pain.

neuroscience↗