Search

Head and neck squamous cell carcinoma (HNSCC) is painful, and perineural invasion (PNI) has been associated with the worst pain. Pain due to HNSCC is diverse and may vary based on clinicopathological factors. This study aims to characterize different pain patterns linked with PNI, its influence on daily functioning, and gain insights into molecular changes and pathways associated with PNI-related pain in HNSCC patients. We conducted a cross-sectional study across 3 medical centers (n = 114), assessing pain phenotypes and their impact on daily functioning using 2 self-reported pain questionnaires, given to patients prior to their cancer surgery. Furthermore, we conducted RNA-seq analysis utilizing the The Cancer Genome Atlas dataset of HNSCC tumor from patients (n = 192) to identify genes relevant to both PNI and pain. Upon adjusting for demographic and clinicopathological variables using linear regression models, we found that PNI independently predicted function-evoked pain according to the University of Calfornia San Francisco Oral Cancer Pain Questionnaire, as well as the worst pain intensity reported in the Brief Pain Inventory. Distinct pain patterns were observed to be associated with daily activities in varying manners. Our molecular analyses revealed significant disruptions in pathways associated with the extracellular matrix structure and organization. The top differentially expressed genes linked to the extracellular matrix are implicated in cancer development, pain, and neurodegenerative diseases. Our data underscore the importance of properly categorizing pain phenotypes in future studies aiming to uncover mechanistic underpinnings of pain. Additionally, we have compiled a list of genes of interest that could serve as targets for both cancer and cancer pain management. PERSPECTIVE: PNI independently predicts function-evoked pain. Different pain phenotypes affect daily activities differently. We identified a list of candidate genes involved in the extracellular matrix structure and function that can be targeted for both cancer and cancer pain control., (Copyright © 2024 United States Association for the Study of Pain, Inc. Published by Elsevier Inc. All rights reserved.)

Bone cancer pain (BCP) represents a prevalent symptom among cancer patients with bone metastases, yet its underlying mechanisms remain elusive. This study investigated the transcriptional regulation mechanism of Kv7(KCNQ)/M potassium channels in DRG neurons and its involvement in the development of BCP in rats. We show that HDAC2-mediated transcriptional repression of kcnq2/kcnq3 genes, which encode Kv7(KCNQ)/M potassium channels in dorsal root ganglion (DRG), contributes to the sensitization of DRG neurons and the pathogenesis of BCP in rats. Also, HDAC2 requires the formation of a corepressor complex with MeCP2 and Sin3A to execute transcriptional regulation of kcnq2/kcnq3 genes. Moreover, EREG is identified as an upstream signal molecule for HDAC2-mediated kcnq2/kcnq3 genes transcription repression. Activation of EREG/EGFR-ERK-Runx1 signaling, followed by the induction of HDAC2-mediated transcriptional repression of kcnq2/kcnq3 genes in DRG neurons, leads to neuronal hyperexcitability and pain hypersensitivity in tumor-bearing rats. Consequently, the activation of EREG/EGFR-ERK-Runx1 signaling, along with the subsequent transcriptional repression of kcnq2/kcnq3 genes by HDAC2 in DRG neurons, underlies the sensitization of DRG neurons and the pathogenesis of BCP in rats. These findings uncover a potentially targetable mechanism contributing to bone metastasis-associated pain in cancer patients., (© 2024. The Author(s).)

The autonomic nerve system (ANS) innervates organs and tissues throughout the body and maintains functional balance among various systems. Further investigations have shown that excessive activation of ANS not only causes disruption of homeostasis, but also may promote tumor formation. In addition, the dynamic interaction between nerve and tumor cells in the tumor microenvironment also regulate tumor progression. On the one hand, nerves are passively invaded by tumor cells, that is, perineural invasion (PNI). On the other hand, compared with normal tissues, tumor tissues are subject to more abundant innervation, and nerves can influence tumor progression through regulating tumor proliferation, metastasis and drug resistance. A large number of studies have shown that nerve-tumor crosstalk, including PNI and innervation, is closely related to the prognosis of patients, and contributes to the formation of cancer pain, which significantly deteriorates the quality of life for patients. These findings suggest that nerve-tumor crosstalk represents a potential target for anti-tumor therapies and the management of cancer pain in the future. In this review, we systematically describe the mechanism by which nerve-tumor crosstalk regulates tumorigenesis and progression., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Pain and depression comorbidity affects patients' physical and mental health, as well as quality of life. Comorbid depressive symptoms in cancer pain have a severe impact on the recognition and treatment of pain. Similarly, cancer pain patients with depression are inclined towards more despair and greater impairment. The mechanisms responsible for the comorbid depressive symptoms in bone cancer pain (BCP) have not been fully delineated. Here, it was reported that the implantation of carcinoma cells into the femoral cavity of mice led to the upregulation of major histocompatibility complex class I (MHC-I) in the hippocampus. This was associated with the activation of microglial signaling pathway mediated by the triggering receptor expressed on myeloid cells 2 protein (TREM2) and DNAX-activating protein of 12 kDa (DAP12). Pain and depression-like behaviors were reversed by the knockdown of hippocampal MHC-I via a lentiviral vector harboring ribonucleic acid interference (RNAi) sequence. Moreover, MHC-I knockdown exhibited a marked reduction in the expression of TREM2 and DAP12. These results suggested that hippocampal MHC-I was involved in BCP and depression comorbidity via upregulating the signals mediated by TREM2/DAP12 in microglia. The suppression of MHC-I could be a potential therapeutic target for BCP., Competing Interests: Declaration of Competing Interest All authors have declared that no conflict of interests exists., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Long noncoding RNA (lncRNA) is implicated in both cancer development and pain process. However, the role of lncRNA in the development of cancer-induced bone pain (CIBP) is unclear. LncRNA NONRATT014888.2 is highly expressed in tibia related dorsal root ganglions (DRGs) in CIBP rats which function is unknown. CIBP was induced by injection of Walker 256 mammary gland tumor cells into the tibia canal of female SD rats. Paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) of rats were measured. Down-regulation of NONRATT014888.2 by siRNA in CIBP rats markedly attenuated hind-paw mechanical pain hypersensitivity. LncRNA-predicted target mRNAs analysis and mRNA sequencing results cued Socs3, Npr3 were related with NONRATT014888.2. Intrathecal injection of NONRATT014888.2-siR206 upregulated Npr3 both in mRNA and protein level. Npr3 was co-expressed in NONRATT014888.2-positive DRGs neurons and mainly located in cytoplasm, but not in Glial fibrillary acidic protein (GFAP)-positive cells. Intrathecal injection of ADV-Npr3 upregulated Npr3 expression and enhanced the PWT of CIBP rats. Our results suggest that upregulated lncRNA NONRATT014888.2 contributed to hyperalgesia in CIBP rats, and the mechanism may through downregulation of Npr3., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objectives: Perineural invasion (PNI) in head and neck cancer (HNC) is a distinct pathological feature used to indicate aggressive tumor behavior and drive treatment strategies. Our study examined the prevalence and predictors of PNI in HNC patients stratified by tumor site., Study Design and Methods: A retrospective analysis of head and neck squamous cell carcinoma (HNSCC) patients who underwent surgical resection at the University of Pittsburgh Medical Center between 2015 and 2018 was performed. Pretreatment pain was assessed at least 1 week before surgery using the Functional Assessment of Cancer Therapy-Head and Neck (FACT-H&N). Demographics, clinical characteristics, and concomitant medications were obtained from medical records. Patients with cancers at the oropharynx and non-oropharynx (i.e., cancer at oral cavity, mandible, larynx) sites were separately analyzed. Tumor blocks were obtained from 10 patients for histological evaluation of intertumoral nerve presence., Results: A total of 292 patients (202 males, median age = 60.94 ± 11.06) were assessed. Pain and PNI were significantly associated with higher T stage (p < 0.001) and tumor site (p < 0.001); patients with non-oropharynx tumors reported more pain and had a higher incidence of PNI compared to oropharynx tumors. However, multivariable analysis identified pain as a significant variable uniquely associated with PNI for both tumor sites. Evaluation of nerve presence in tumor tissue showed 5-fold higher nerve density in T2 oral cavity tumors compared to oropharyngeal tumors., Conclusions: Our study finds that PNI is associated with pretreatment pain and tumor stage. These data support the need for additional research into the impact of tumor location when investigating targeted therapies of tumor regression., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Bone cancer pain (BCP) is severe chronic pain caused by tumor metastasis to the bones, often resulting in significant skeletal remodeling and fractures. Currently, there is no curative treatment. Therefore, insight into the underlying mechanisms could guide the development of mechanism-based therapeutic strategies for BCP. We speculated that Rac1/PAK1 signaling plays a critical role in the development of BCP. Tumor cells implantation (TCI) into the tibial cavity resulted in bone cancer-associated mechanical allodynia. Golgi staining revealed changes in the excitatory synaptic structure of WDR (Wide-dynamic range) neurons in the spinal cord, including increased postsynaptic density (PSD) length and thickness, and width of the cleft. Behavioral and western blotting test revealed that the development and persistence of pain correlated with Rac1/PAK1 signaling activation in primary sensory neurons. Intrathecal injection of NSC23766, a Rac1 inhibitor, reduced the persistence of BCP as well as reversed the remodeling of dendrites. Therefore, we concluded that activation of the Rac1/PAK1 signaling pathway in the spinal cord plays an important role in the development of BCP through remodeling of dendritic spines. Modulation of the Rac1/PAK1 pathway may be a potential strategy for BCP treatment.

Tumor innervation is a common phenomenon with unknown mechanism. Here, we discovered a direct mechanism of tumor-associated macrophage (TAM) for promoting de novo neurogenesis via a subset showing neuronal phenotypes and pain receptor expression associated with cancer-driven nocifensive behaviors. This subset is rich in lung adenocarcinoma associated with poorer prognosis. By elucidating the transcriptome dynamics of TAM with single-cell resolution, we discovered a phenomenon "macrophage to neuron-like cell transition" (MNT) for directly promoting tumoral neurogenesis, evidenced by macrophage depletion and fate-mapping study in lung carcinoma models. Encouragingly, we detected neuronal phenotypes and activities of the bone marrow-derived MNT cells (MNTs) in vitro. Adoptive transfer of MNTs into NOD/SCID mice markedly enhanced their cancer-associated nocifensive behaviors. We identified macrophage-specific Smad3 as a pivotal regulator for promoting MNT at the genomic level; its disruption effectively blocked the tumor innervation and cancer-dependent nocifensive behaviors in vivo. Thus, MNT may represent a precision therapeutic target for cancer pain.

Bone metastatic pain is thought to be a severe type of cancer pain that has refractory characteristics and a long duration. This study is aimed at exploring the brain functional connectivity (FC) pattern in lung cancer patients with bone metastatic pain. In this study, 27 lung cancer patients with bone metastatic pain (CP+), 27 matched lung cancer patients without pain-related complaints (CP-), and 27 matched healthy controls (HC) were recruited. All participants underwent fMRI data acquisition and clinical assessments. One-way ANOVA or a Mann-Whitney U test was applied to compare clinical data according to data distribution. Seventeen hypothesis-driven pain-related brain regions were selected as regions of interest (ROIs). FC values among pain-related brain regions across the three groups were computed by using ROI-ROI functional connectivity analysis. ANCOVA with a post hoc test was applied to compare FC differences among the three groups. p < 0.05 indicated statistical significance. Correlation analysis was conducted to explore the potential relationship between the FC values and clinical characteristics. Except for years of education, no significant differences were revealed among the three groups in age, gender, or neuropsychological assessment. In the CP+ group, FC alterations were mainly concentrated in the dorsal lateral prefrontal cortex (DLPFC), anterior cingulate cortex (ACC), secondary somatosensory cortex (SII), and amygdala compared to the CP- group. Among these brain regions with statistical differences, FC between the right DLPFC and the right ACC showed a positive correlation with the duration of cancer pain in the CP+ group. In addition, in the CP- group, altered FC was found in the bilateral SII, ACC, and thalamus compared to the HC group. Altered FC in pain-related brain regions may be a brain pattern of bone metastatic pain and may be associated with the long duration of cancer pain., Competing Interests: The authors declare that they have no conflicts of interests., (Copyright © 2022 Xiaoyu Zhou et al.)

Bone cancer pain (BCP) is the most frequently observed chronic cancer pain, and its development remains largely unexplored. Dysregulation of non-coding RNAs greatly contributes to the pathogenesis of BCP. In the present study, we found a new long noncoding RNA (lncRNA), NONRATT009773.2, and investigated its role in the spinal cord of BCP rats. Our results showed that NONRATT009773.2 was significantly up-regulated in BCP model rats, whereas depletion of NONRATT009773.2 attenuated BCP. In contrast, overexpression of NONRATT009773.2 triggered pain-like symptoms in normal animals. Moreover, NONRATT009773.2 functioned as a microRNA (miRNA) sponge to absorb miR-708-5p and up-regulated miRNA downstream target CXCL13, which plays fundamental roles in the initiation and maintenance of neuroinflammation and hyperalgesia. Collectively, our current findings indicated that NONRATT009773.2 could be employed as a new therapeutic target for BCP., (© 2022 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.)

Tumor metastasis to bone is often accompanied by a severe pain syndrome (cancer-induced bone pain, CIBP) that is frequently unresponsive to analgesics, which markedly reduces patient quality of life and cancer treatment tolerance in patients. Prolonged pain can induce hypersensitivity via spinal plasticity, and several recent studies have implicated the involvement of vascular endothelial growth factor-A (VEGF-A) signaling in this process. Here, we speculated that CIBP is associated with VEGF-A/VEGFR2 signaling in the spinal cord. A mouse model of CIBP was established by intramedullary injection of Lewis lung carcinoma (LLC) cells in the mouse femur. Pain sensitization and potential amelioration via VEGF-A/VEGFR2 blockade were measured using paw withdrawal threshold to mechanical stimulation and paw withdrawal latency to thermal. Spinal VEGF-A/VEGFR2 signaling was blocked by intrathecal injection of the VEGF-A antibody or the specific VEGFR2 inhibitor ZM323881. Changes in the expression levels of VEGF-A, VEGFR2, and other pain-related signaling factors were measured using western blotting and immunofluorescence staining. Mice after LLC injection demonstrated mechanical allodynia and thermal hyperalgesia, both of which were suppressed via anti-VEGF-A antibody or ZM323881. Conversely, the intrathecal injection of exogenous VEGF-A was sufficient to cause pain hypersensitivity in naïve mice via the VEGFR2-mediated activation of protein kinase C. Moreover, the spinal blockade of VEGF-A or VEGFR2 also suppressed N-methyl-D-aspartate receptor (NMDAR) activation and downstream Ca2+-dependent signaling. Thus, spinal VEGF-A/VEGFR2/NMDAR signaling pathways may be critical mediators of CIBP.

Rationale: Implicit racial bias affects many human interactions including patient-physician encounters. Its impact, however, varies between studies. We assessed the effects of physician implicit, racial bias on their management of cancer-related pain using a randomized field experiment., Methods: We conducted an analysis of a randomized field experiment between 2012 and 2016 with 96 primary care physicians and oncologists using unannounced, Black and White standardized patients (SPs)who reported uncontrolled bone pain from metastatic lung cancer. We assessed implicit bias using a pain-adaptation of the race Implicit Association Test. We assessed clinical care by reviewing medical records and prescriptions, and we assessed communication from coded transcripts and covert audiotapes of the unannounced standardized patient office visits. We assessed effects of interactions of physicians' implicit bias and SP race with clinical care and communication outcomes. We conducted a slopes analysis to examine the nature of significant interactions., Results: As hypothesized, physicians with greater implicit bias provided lower quality care to Black SPs, including fewer renewals for an indicated opioid prescription and less patient-centered pain communication, but similar routine pain assessment. In contrast to our other hypotheses, physician implicit bias did not interact with SP race for prognostic communication or verbal dominance. Analysis of the slopes for the cross-over interactions showed that greater physician bias was manifested by more frequent opioid prescribing and greater discussion of pain for White SPs and slightly less frequent prescribing and pain talk for Black SPs with the opposite effect among physicians with lower implicit bias. Findings are limited by use of an unvalidated, pain-adapted IAT., Conclusion: Using SP methodology, physicians' implicit bias was associated with clinically meaningful, racial differences in management of uncontrolled pain related to metastatic lung cancer. There is favorable treatment of White or Black SPs, depending on the level of implicit bias., Competing Interests: The authors have declared that no competing interests exist.

Pain is one of the most severe concerns in tongue cancer patients. However, the underlying mechanisms of tongue cancer pain are not fully understood. We investigated the molecular mechanisms of tongue cancer-induced mechanical allodynia in the tongue by squamous cell carcinoma (SCC) inoculation in rats. The head-withdrawal threshold of mechanical stimulation (MHWT) to the tongue was reduced following SCC inoculation, which was inhibited by intracisternal administration of 10Panx, an inhibitory peptide for pannexin 1 (PANX1) channels. Immunohistochemical analyses revealed that the expression of PANX1 was upregulated in the trigeminal spinal subnucleus caudalis (Vc) following SCC inoculation. The majority of PANX1 immunofluorescence was merged with ionized calcium-binding adapter molecule 1 (Iba1) fluorescence and a part of it was merged with glial fibrillary acidic protein (GFAP) fluorescence. Spike frequencies of Vc nociceptive neurons to noxious mechanical stimulation were significantly enhanced in SCC-inoculated rats, which was suppressed by intracisternal 10Panx administration. Phosphorylated extracellular signal-regulated kinase (pERK)-immunoreactive (IR) neurons increased significantly in the Vc after SCC inoculation, which was inhibited by intracisternal 10Panx administration. SCC inoculation-induced MHWT reduction and increased pERK-IR Vc neuron numbers were inhibited by P2X7 purinoceptor (P2X7R) antagonism. Conversely, these effects were observed in the presence of P2X7R agonist in SCC-inoculated rats with PANX1 inhibition. SCC inoculation-induced MHWT reduction was significantly recovered by intracisternal interleukin-1 receptor antagonist administration. These observations suggest that SCC inoculation causes PANX1 upregulation in Vc microglia and adenosine triphosphate released through PANX1 sensitizes nociceptive neurons in the Vc, resulting in tongue cancer pain.

Bone cancer pain (BCP) was associated with microRNA dysregulation. In this study, we intended to clarify the potential role of miR-135-5p in a BCP mouse model, which was established by tumor cell implantation (TCI) in the medullary cavity of the mouse femur. The BCP-related behaviors were tested, including the paw withdrawal mechanical threshold (PWMT) and number of spontaneous flinches (NSF). The miRNA expression profiles in astrocytes of the sham and tumor groups were compared, and miRNA microarray and quantitative real-time PCR (qRT-PCR) assays confirmed that the amount of expression of miR-135-5p was significantly decreased in astrocytes of the tumor group. Gain- and loss-of-function studies showed that miR-135-5p could inhibit astrocyte activation and inflammation cytokine (TNF-α and IL-1β) expression. The relation between miR-135-5p and JAK2 was detected by bioinformatic analysis and dual luciferase reporter gene assay. By conducting in vitro experiments, it was shown that the miR-135-5P mimics lowered the level of JAK2/STAT3 proteins and inflammatory factors in astrocytes. Moreover, in vivo analysis on BCP mice model indicated that the miR-135-5p agonist could sufficiently increase PWMT and decrease NSF. Meanwhile, reduced activation of astrocytes in the spinal cord, as well as decreased expression of JAK2/STAT3 and inflammatory mediators, were found after miR-135-5p agonist treatment. Collectively, the results showed that miR-135-5p could potentially reduce BCP in mice through inhibiting astrocyte-mediated neuroinflammation and blocking of the JAK2/STAT3 signaling pathway, indicating that the upregulation of miR-135-5P could be a therapeutic focus in BCP treatment., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Cancer-induced bone pain (CIBP) is one of the most severe types of chronic pain which the involved mechanisms are largely unknown. LncRNA has been found to play critical roles in chronic pain. However, its function in peripheral nervous system in CIBP remains unknown. Identifying the different lncRNA expression pattern is essential for understanding the genetic mechanisms underlying the pathogenesis of CIBP., Methods: The model was induced by injection of Walker 256 cells into the rat tibia canal. Behavior tests and X-ray microtomography (MicroCT) analysis were performed to verify the model's establishment. L2-L5 DRGs were harvested at 14-day post operation and the differential lncRNA and mRNA expression patterns were investigated by microarray analyses. RT-qPCR analysis and RNA interference were performed for expression and function verifications. Bioinformatics analysis was conducted for further function study., Results: CIBP rats showed hyperalgesia and the MicroCT analysis showed tibia destruction. A total of 73 lncRNAs and 187 mRNAs were dysregulated. The expressions of several lncRNAs and mRNAs were validated by RT-qPCR experiment. Biological analyses showed that the changed mRNAs were mainly related to cellular and single-organism process, cell and cell part, binding function and immune system pathway. The top 30 lncRNA-predicted mRNAs are mainly related to peroxisome, DNA-dependent DNA replication, double-stranded RNA binding, tuberculosis and purine metabolism. 56 lncRNAs (30 downregulated and 26 upregulated) and 179 DEGs (35 downregulated and 144 upregulated) have a significant correlation and constructed a co-expression network. Downregulation of lncRNA NONRATT021203.2 by siRNA intrathecal injection increased PWL and WBD in CIBP rats, alleviating cancer induced bone hyperalgesia., Conclusion: LncRNA played important roles in regulation of CIBP or mRNA expression in peripheral neuropathy in CIBP. These alterd mRNAs and lncRNAs might be potential therapeutic targets for the treatment of CIBP., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Bone cancer pain (BCP) is a clinical pathology that urgently needs to be solved, but research on the mechanism of BCP has so far achieved limited success. Nuclear factor erythroid 2 (NFE2)-related factor 2 (Nrf2) has been shown to be involved in pain, but its involvement in BCP and the specific mechanism have yet to be examined. This study aimed to test the hypothesis that BCP induces the transfer of Nrf2 from the cytoplasm to the nucleus and further promotes nuclear transcription to activate heme oxygenase-1 (HO-1) and inhibit the activation of nuclear factor-kappa B (NF-κB) signalling, ultimately regulating the neuroinflammatory response. Von-Frey was used for behavioural analysis in rats with BCP, whereas western blotting, real-time quantitative PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) were used to detect molecular expression changes, and immunofluorescence was used to detect cellular localization. We demonstrated that BCP induced increased Nrf2 nuclear protein expression with decreased cytoplasmic protein expression in the spinal cord. Further increases in Nrf2 nuclear protein expression can alleviate hyperalgesia and activate HO-1 to inhibit the expression of NF-κB nuclear protein and inflammatory factors. Strikingly, intrathecal administration of the corresponding siRNA reversed the above effects. In addition, the results of double immune labelling revealed that Nrf2 and NF-κB were coexpressed in spinal cord neurons of rats with BCP. In summary, these findings suggest that the entry of Nrf2 into the nucleus promotes the expression of HO-1, inhibiting activation of the NF-κB signalling pathway, reducing neuroinflammation and ultimately exerting an anti-nociceptive effect., (© 2021 The Authors. Journal of Neurochemistry published by John Wiley & Sons Ltd on behalf of International Society for Neurochemistry.)

Aims: Breast cancer-induced chronic pain is usually treated with opioids, but these compounds cause various adverse effects. Transient receptor potential ankyrin 1 (TRPA1) is involved in cancer pain; also, endogenous TRPA1 agonists are associated with cancer pain development. The aim of this study was to observe the antinociceptive effect of a repeated-dose TRPA1 antagonist administration and the production of endogenous TRPA1 agonists and TRPA1 expression in bone tissue in a model of breast cancer pain in mice. Second, we used a sequence reading archive (SRA) strategy to observe the presence of this channel in the mouse bone and in mouse bone cell lines., Main Methods: We used BALB/c mice for experiments. The animals were subjected to the tumor cell inoculation (4 T1 strain). HC-030031 (a TRPA1 antagonist) treatment was done from day 11 to day 20 after tumor inoculation. TRPA1 expression and biochemical tests of oxidative stress were performed in the bone of mice (femur). SRA strategy was used to detect the TRPA1 presence., Key Findings: Repeated treatment with the TRPA1 antagonist produced an antinociceptive effect. There was an increase in hydrogen peroxide levels, NADPH oxidase and superoxide dismutase activities, but the expression of TRPA1 in the bone tissue was not altered. SRA did not show TRPA1 residual transcription in the osteoblast and osteoclast cell lines, as well as for mice cranial tissue and in mouse osteoclast precursors., Significance: The TRPA1 receptor is a potential target for the development of new painkillers for the treatment of bone cancer pain., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Although macrophages (MΦ) are known to play a central role in neuropathic pain, their contribution to cancer pain has not been established. Here we report that depletion of sciatic nerve resident MΦs (rMΦ) in mice attenuates mechanical/cold hypersensitivity and spontaneous pain evoked by intraplantar injection of melanoma or lung carcinoma cells. MΦ-colony stimulating factor (M-CSF) was upregulated in the sciatic nerve trunk and mediated cancer-evoked pain via rMΦ expansion, transient receptor potential ankyrin 1 (TRPA1) activation, and oxidative stress. Targeted deletion of Trpa1 revealed a key role for Schwann cell TRPA1 in sciatic nerve rMΦ expansion and pain-like behaviors. Depletion of rMΦs in a medial portion of the sciatic nerve prevented pain-like behaviors. Collectively, we identified a feed-forward pathway involving M-CSF, rMΦ, oxidative stress, and Schwann cell TRPA1 that operates throughout the nerve trunk to signal cancer-evoked pain. SIGNIFICANCE: Schwann cell TRPA1 sustains cancer pain through release of M-CSF and oxidative stress, which promote the expansion and the proalgesic actions of intraneural macrophages. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/12/3387/F1.large.jpg., (©2021 American Association for Cancer Research.)

To evaluate the effects of allicin on mediators of pain secreted by oral cancer cells in vitro, single-cell suspensions were prepared by enzymatic method from oral squamous cell carcinoma (OSCC). Cancer stem cells were isolated by the CD133+ selection method with magnetic cell sorting. Stemness markers were checked in both cancer cells and cancer stem cells by RT-PCR. Comparative analysis of pain mediators TNF-alpha, IL-8, and endothelin at both RNA and protein levels for normal epithelial cells, cancer cells, and cancer stem cells was carried out with and without allicin treatment. CD133 and CD44 expression levels were checked in cancer cells and cancer stem cells flow cytometrically. Allicin inhibited both gene and protein expression of TNF-alpha, IL-8, and endothelin in both cancer cells and cancer stem cells. Allicin is more likely to be a promising treatment in alleviating the levels of pain and inflammation in OSCCs.

Pain is a major complication of cancer and significantly affects the quality of life. Cerebrospinal fluid-contacting nucleus (CSF-CN) has been reported to be involved in the development of neuropathic pain and inflammatory pain. However, whether CSF-CN contributes to cancer-induced bone pain (CIBP) remains unknown. In this study, we aimed to illustrate the role of CSF-CN in the pathogenesis of CIBP and identify its potential mechanism via the MKP-1-mediated MAPK pathway. The Walker 256 cancer cells were injected into the tibia cavity of female Sprague-Dawley rats to induce CIBP models. Intracerebroventricular injection of cholera toxin subunit B- saporin (CB-SAP) was performed to "knockout" the CSF-CN. Morphine and LV-MKP-1 were applied. Mechanical and thermal hyperalgesia behaviors, double immunofluorescence staining and Western blot were conducted after CIBP induction. The results revealed that CIBP significantly reduced the mechanical withdrawal threshold and the thermal threshold. Double immunofluorescence staining revealed that c-Fos-positive neurons in CSF-CN were significantly higher in the CIBP group than that in the sham group. Targeted ablation of CSF-CN dramatically aggravated pain sensitivity. Moreover, MKP-1 was down-regulated in the CSF-CN after CIBP induction. Pharmacological intervention with morphine significantly ameliorated the mechanical and thermal hyperalgesia through reversing the down-expression of MKP-1 in the CSF-CN on day 14 after CIBP induction. Mechanically, overexpression of MKP-1 by LV-MKP-1 injection significantly relieved CIBP via inhibiting the expression of phosphorylated p38, which subsequently decreased the protein levels of Bax, cleaved caspase-3 and Iba-1, and reduced the mRNA levels of IL-1β, TNF-α and IL-6 in CSF-CN. In conclusion, CSF-CN contributed to CIBP via regulating the MKP-1-mediated p38-MAPK pathway. Future therapy targeting the expression of MKP-1 in the CSF-CN may be a promising new choice., Competing Interests: Declaration of competing interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Purpose: Bone destruction and pain caused by cancer is one of the most devastating complications of cancer patients with bone metastases, and it seriously affects the quality of patients' life. Extracellular matrix metalloproteinase inducer (EMMPRIN) is a cell adhesion molecule with increased expression in a variety of tumors. This study focused to clarify the specific function of EMMPRIN in bone metastasis of breast cancer., Materials and Methods: Adenovirus with shRNA-EMMPRIN was transfected into MRMT-1 rat breast carcinoma cells, and the MRMT-1 cells with different expression levels of EMMPRIN were implanted into the bone marrow cavity of rat tibia. Next, the effect of down-regulation of EMMPRIN was evaluated as follows: bone damage was detected by X-ray radiological and tartrate-resistant acid phosphatase staining; the tumor burden was evaluated by hematoxylin and eosin staining; the test of pain-related behaviors was assessed used the bilateral paw withdrawal mechanical threshold; and the levels of secretory factors in tumor conditioned medium were determined by using enzyme-linked immunosorbent assay., Results: We found that down-regulation of EMMPRIN in tumor cells can simultaneously reduce tumor burden, relieve cancer-induced bone destruction and pain., Conclusion: EMMPRIN is expected to be a therapeutic target for relieving bone metastasis of breast cancer and alleviating cancer-induced bone destruction and pain. The method of targeting EMMPRIN may be a promising strategy for the treatment of cancer in the future.

Background: While the prognosis of patients with Ewing sarcoma (EwS) is improving, little is known about the frequency of pain and its risk factors in survivors of EwS. This study aims to analyse the prevalence and risk factors of pain and its predictive value for recurrence., Patients and Methods: In patients with remission after treatment of EwS, frequency and characteristics of pain within the first 5 years of follow up were assessed retrospectively., Results: Of 80 patients, 37 (46%) presented with at least one episode of pain. Chronic pain (>3 months) was observed in 10 patients (13%). Experience of at least one episode of pain was associated with prior combined local treatment (surgery and radiation compared to surgery alone; odds ratio [OR] 5.83, 95% confidence interval [CI] 1.43-34.9, P = .007). A total of 59 episodes of pain were observed, including 47 acute and 12 chronic episodes. Lower limb pain accounted for 46% (27/59) of all episodes of pain, and was associated with primary tumour of the pelvis or lower extremity (OR 4.29, 95% CI 1.18-18.21, P = .025), which represented 64% (51/80) of all EwS. The positive predictive value of pain for recurrence was only 12%., Conclusion: Pain is a common problem in survivors of EwS, which mostly affects the lower extremity, and should be regularly assessed. Interventions to reduce pain may be particularly important in patients with combined local treatment with surgery and radiation, who seem to be at considerably increased risk for pain. Patients presenting with pain should be examined for recurrence., (© 2020 Wiley Periodicals LLC.)

Background: Deficits in knowledge and comfort related to pain management have been demonstrated in adult hematology/oncology fellows. No such evaluation has been undertaken in pediatric hematology/oncology (PHO) trainees., Procedure: An IRB-approved survey was administered to PHO fellows throughout the United States (US) to assess comfort with opioid dosing, attitudes related to the use of opioids, and knowledge of basic concepts including weight-based dosing, incomplete cross-tolerance, and management of side effects., Results: Email addresses were obtained for 132 fellows from 37 programs. Seventy-eight (59%) fellows participated. No significant difference was demonstrated between training level and comfort with dosing opioids in an opioid-naive patient, though a smaller proportion of first-year fellows (65%) reported comfort compared to more senior fellows (85.2% of second-year fellows, 80.6% of third- and fourth-year fellows). First-year fellows correctly answered a mean of 5.05 ± 0.43 out of 10 objective knowledge questions; second-year fellows answered 5.74 ± 0.35 correctly, and third- and fourth-year fellows 5.58 ± 0.30. The majority of respondents chose an appropriate dose of intravenous morphine based on weight (92%), and identified a low-dose naloxone drip as an appropriate intervention for opioid-induced pruritis (91%). However, the remainder of the questions had a correct response rate of 15-68%., Conclusion: This study characterizes PHO fellows' knowledge and comfort with prescribing opioids. Despite high levels of reported comfort, PHO fellows in all levels of training demonstrated knowledge gaps. PHO fellows may benefit from further education in pain management., (© 2020 Wiley Periodicals LLC.)

Cancer pain, especially bone cancer pain, is a pain state often caused by inflammation or dysfunctional nerves. Moreover, in the management of cancer pain, opioid especially morphine is widely used, however, it also brings severe side effects such as morphine tolerance to the patient (Deandrea et al., 2008). A growing body of literatures demonstrated that neuroinflammation is mediated by microglia. As the macrophages like immune cells, microglia play an important role in the pathogenesis of cancer pain and morphine tolerance. Microglia acquire different activation states to regulate the function of these cells. As to M1 phenotype, microglia release pro-inflammatory cytokines and neurotoxic molecules that promote inflammation and cytotoxic reactions. Conversely, when microglia represent M2 phenotypes secreting anti-inflammatory cytokines and nutrient factors that promote the function of repair, regeneration and restore homeostasis. A better understanding of microglia activation in cancer pain and morphine tolerance is crucial for the development of hypothesized neuroprotective drugs. Targeting microglia different polarization states by the inhibition of their deleterious pro-inflammatory neurotoxicity and/or enhancing their beneficial anti-inflammatory protective function seems to be an effective treatment for cancer pain and morphine tolerance., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective: This study aimed to compare the clinical effects of uterine artery embolization (UAE) with those of high-intensity focused ultrasound (HIFU) ablation for the treatment of symptomatic uterine myomas., Data Sources: We searched PubMed, EMBASE, Web of Science, Cochrane Library, Google Scholar, and ClinicalTrials.gov for studies from January 2000 to August 2020. Related articles and relevant references of the included studies were also searched., Methods of Study Selection: Two researchers independently performed the data selection. We included comparative studies that compared the clinical outcomes of UAE with those of HIFU ablation in women with myomas., Tabulation, Integration, and Results: We assessed the study quality using the Cochrane Handbook for Systematic Reviews of Interventions for evaluating the risk of bias. Two independent researchers performed the article selection according to the screening criteria and rated the quality of evidence for each article. We calculated pooled mean difference with 95% confidence interval (CI) for continuous data and relative risk (RR) with 95% CI for dichotomous data. The systematic review registration number is CRD42020199630 on the International Prospective Register of Systematic Reviews. A total of 7 articles (5 trials), involving 4592 women with symptomatic uterine myomas, were included in the meta-analysis. Compared with the HIFU ablation group, the decrease in "uterine fibroid symptom" scores as well as the increase in quality-of-life scores at the time of follow-up were higher in the UAE group, with overall mean difference 19.54 (95% CI, 15.21-23.87; p <.001) and 15.72 (95% CI, 8.30-23.13; p <.001), respectively. The women in the UAE group had a significantly lower reintervention rate (RR 0.25; 95% CI, 0.15-0.42; p <.001). The women undergoing UAE had a significantly lower pregnancy rate than those undergoing HIFU ablation (RR 0.06; 95% CI, 0.01-0.45; p = .006). The difference in the incidence of adverse events between the 2 groups was not statistically significant (p = .53)., Conclusion: Compared with HIFU ablation, UAE provided more significant alleviation of symptoms and improvement in quality of life, lower postoperative reintervention rate, and lower pregnancy rate for women with uterine myomas. However, we cannot conclude that HIFU ablation is more favorable for desired pregnancy than UAE because of the confounding factors., (Copyright © 2020 AAGL. Published by Elsevier Inc. All rights reserved.)

Background: Cancer-related pain, usually associated with bone metastases, is a frequent and debilitating morbidity in patients with prostate cancer. To date there are only limited data regarding the prognostic role of pain in men with metastatic castration-sensitive prostate cancer (mCSPC). The objective of our analysis was to assess if the presence of pain can be considered an independent prognostic factor in mCSPC patients., Methods: A retrospective analysis was performed on patients with mCSPC referring to six oncology centers in Italy. Clinical and pathological features were recorded. Patients were considered to have pain if this was reported within the patient's file or in case of a chronic analgesic therapy was found among the concomitant medications. Survivals were estimated by the Kaplan-Meier method, and compared across groups using the log-rank test. Cox proportional hazard models, stratified according to the baseline characteristics, were used to estimate hazard ratios for overall survival (OS). All the variables were significant if p < 0.05., Results: Data about pain were available for 365 cases and pain was present in 34.8% of patients. Pain was mainly associated with high value of prostate-specific antigen, metastatic bone extension regardless of the site, and lymph node involvement. mCSPC patients with pain had in most of the cases high-volume or Hr disease, and significant shorter OS (27.0 vs. 58.2 months, p < 0.001) and PFS (10.1 vs. 17.4 months, p < 0.001) compared to those without pain. The negative impact of pain on OS remained significant even if adjusted for CHAARTED or LATITUDE classification, and other significant baseline prognostic factors., Conclusions: This analysis supports the poor prognostic role of cancer-related pain in the setting of mCSPC patients. A prospective validation is required.

Objective: To investigate the effectiveness of pre-procedural oral mefenamic acid compared with placebo in women undergoing Loop Electrosurgical Excision Procedure (LEEP) with intracervical lidocaine injection., Study Designs: A prospective double-blinded randomized control trial. Materials, Setting, Methods: Women undergoing LEEP for any indications were asked to participate in the study. The participants were randomly allocated into two groups. In group 1 (oral mefenamic acid), the participants were offered oral mefenamic acid (500 mg) for 30 minutes before procedures. In group 2 (placebo), the patients were given oral placebo (identical tablet) for 30 minutes before operation. All participants received immediate 10 mL of 2% lidocaine with 1:100,000 of epinephrine intracervical injection before undergoing the LEEP. All participants were excised in one piece of LEEP. No top-hat excision in this study.  The patients graded their pain on a 10-cm visual analog scale (VAS) at different points during the procedure, including speculum insertion, at starting excision, and 30 minutes post excision. Primary outcomes revealed the difference of VAS during all steps of LEEP by generalized estimating equations procedure., Results: Sixty participants (30 in mefenamic group and 30 in placebo group) participated in this study. The study did not find differences of VAS during all steps of LEEP and analgesic drug requirement at 30 minutes after LEEP procedure. All patients reported no immediate complications and no intervention-related adverse events were observed., Conclusion: Using pre-procedural oral mefenamic acid before LEEP procedure was not associated with pain reduction during all steps of excision., .

Advanced head and neck cancer (HNC) can invade facial bone and cause bone pain, thus posing a significant challenge to the quality of life of patients presenting with advanced HNC. The present study was designed to investigate HNC bone pain (HNC‑BP) in an intratibial mouse xenograft model that utilized an HNC cell line (SAS cells). These mice develop HNC‑BP that is associated with an expression of phosphorylated ERK1/2 (pERK1/2), which is a molecular indicator of neuron excitation in dorsal root ganglia (DRG) sensory neurons. Our experiments demonstrated that the inhibition of high mobility group box 1 (HMGB1) by short hairpin (shRNA) transduction, HMGB1 neutralizing antibody, and HMGB1 receptor antagonist suppressed the HNC‑BP and the pERK1/2 expression in DRG. It was also observed that HNC‑derived HMGB1 increased the expression of the acid‑sensing nociceptor, transient receptor potential vanilloid 1 (TRPV1), which is a major cause of osteoclastic HNC‑BP in DRG. Collectively, our results demonstrated that HMGB1 originating in HNC evokes HNC‑BP via direct HMGB1 signaling and hypersensitization for the acid environment in sensory neurons.

Wnt5b, a member of Wnt family, plays multiple roles in tumor progression and metastasis. However, whether Wnt5b contributes to the sensitization of dorsal root ganglia (DRG) neurons and pathogenesis of bone cancer pain still remains unclear. Here, we found that the protein expression of Wnt5b and its atypical tyrosine protein kinase receptor Ryk was upregulated in ipsilateral DRGs in tumor-bearing mice. Application of Wnt5b evoked an increased discharge frequency in isolated DRG neurons and pain hypersensitivity in naïve mice which were almost completely prevented by anti-Ryk antibody. Moreover, intrathecal injection of anti-Ryk antibody to tumor-bearing mice significantly inhibited bone cancer-induced mechanic allodynia and thermal hyperalgesia. Subsequently, we also demonstrated that application of Wnt5b to cultured DRG neurons could enhance membrane P2X3 receptors and α,β-meATP-induced currents. Intrathecal injection of calmodulin-dependent protein kinase II (CaMKII) inhibitor KN93 or P2X3 receptors antagonist A317491 almost completely abolished Wnt5b-induced mechanical allodynia and thermal hyperalgesia in mice. Meanwhile, pretreatment with anti-Ryk antibody or CaMKII inhibitor KN93 can attenuate bone-cancer induced the upregulation of P2X3 membrane protein as well as pain hypersensitivity. These findings suggested that Wnt5b/Ryk promoted the trafficking of P2X3 receptors to the membrane via the activation of CaMKII in primary sensory neurons, resulting in peripheral sensitization and bone cancer-induced pain. Our results may offer a potential therapeutic strategy for bone cancer pain., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background and Objectives: Bone cancer pain (BCP) remains a difficult clinical problem. This study examined whether pioglitazone, a peroxisome proliferator-activated receptor gamma (PPARγ) agonist, is effective for attenuating BCP, and investigated the interaction between activation of PPARγ and phosphatase and tensin homolog deleted from chromosome 10 (PTEN) / mammalian target of rapamycin (mTOR) signal in the spinal dorsal horn (SDH) of BCP rats., Methods: We tested the effects of intrathecal (i.t.) injection of adenovirus-mediated PTEN (Ad-PTEN), PTEN antisense oligonucleotide (Ad-antisense PTEN), mTOR inhibitor rapamycin, pioglitazone and PPARγ antagonist GW9662 on bone cancer-induced mechanical allodynia by measuring the paw withdrawal threshold (PWT). Western blot or immunofluorescence examined the expression of spinal PPARγ, PTEN, mTOR, p-mTOR and p-S6K1., Results: Bone cancer did not alter total mTOR expression but caused significant downregulation of PTEN and upregulation of p-mTOR and p-S6K1 in spinal neurons. Rapamycin markedly reduced BCP. Upregulation of spinal PTEN by i.t. Ad-PTEN significantly relieved BCP and downregulated p-mTOR and p-S6K1; while i.t. Ad-antisense PTEN led to the opposite effects of Ad-PTEN. Spinal PPARγ expression increased in BCP rats, co-localizing mainly with neurons and a few astrocytes, but not in microglia. Pioglitazone (500 μg/day i.t. for one week, from 7 days after surgery) attenuated BCP, further increased expression of PPARγ, and inhibited downregulation of PTEN and upregulation of p-mTOR and p-S6K1 in the SDH. Pioglitazone's analgesic effect was enhanced by Ad-PTEN and attenuated by Ad-antisense PTEN. Blockade of PPARγ with GW9662 (300 μg i.t. 15 min prior to pioglitazone) reversed the effects of pioglitazone on BCP and regulations of PPARγ/PTEN/mTOR signal., Conclusions: Intrathecal pioglitazone administration alleviates BCP by regulating the PPARγ/PTEN/mTOR signal in the SDH. Our data provided new insight in the therapeutic strategy in BCP management., (Copyright © 2020 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Recently programmed death-ligand 1 (PD-L1) receptor PD-1 was found in dorsal root ganglion (DRG) neurons, and PD-L1 activates PD-1 to inhibit inflammatory and neuropathic pain by modulating neuronal excitability. However, the downstream signaling of PD-1 in sensory neurons remains unclear. Here, we show that PD-L1 activated Src homology 2 domain-containing tyrosine phosphatase-1 (SHP-1) to downregulate transient receptor potential vanilloid 1 (TRPV1) in DRG neurons and inhibit bone cancer pain in mice. Local injection of PD-L1 produced analgesia. PD-1 in DRG neurons colocalized with TRPV1 and SHP-1. PD-L1 induced the phosphorylation of SHP-1 in DRG TRPV1 neurons and inhibited TRPV1 currents. Loss of TRPV1 in mice abolished bone cancer-induced thermal hyperalgesia and PD-L1 analgesia. Conditioned deletion of SHP-1 in NaV1.8+ neurons aggravated bone cancer pain and diminished the inhibition of PD-L1 on TRPV1 currents and pain. Together, our findings suggest that PD-L1/PD-1 signaling suppresses bone cancer pain via inhibition of TRPV1 activity. Our results also suggest that SHP-1 in sensory neurons is an endogenous pain inhibitor and delays the development of bone cancer pain via suppressing TRPV1 function.

Background and Aims: Oral mucositis (OM) is a common and distressing toxicity in children on chemotherapy. There are a limited number of safe and effective therapeutic options available for OM. Ketamine oral rinse has shown promising results in a few studies in adults. This randomized, double-blind placebo-controlled trial aimed to test the efficacy of ketamine mouthwash in reducing chemotherapy-induced severe OM pain in children., Methods: Children aged 8-18 years with severe OM were randomized to a single dose of ketamine mouthwash (4 mg/mL solution; dose 1 mg/kg) or a placebo. A sample size of 44 patients was determined. Pain score (6-point faces scale) was noted at baseline and 15, 30, 45, 60, 120, 180, and 240 min. The outcome variables were a reduction in pain score, need for rescue medications, and adverse events., Results: The baseline characteristics were comparable in the two groups. The mean OM pain at 60 min decreased by 1.64 points (CI 1.13-2.14) in the ketamine group and 1.32 points (CI 0.76-1.87) in the placebo group (P = 0.425), with a group difference of 0.32 points. Rescue pain medication (at 60 min) was required in 13.6% in the ketamine group and 18.2% in the placebo group (P = 1.000). No significant adverse events were observed., Conclusions: Among children on cancer chemotherapy with severe OM, ketamine mouthwash at a dose of 1 mg/kg did not significantly reduce OM pain. It did not decrease the need for rescue pain medications. Further research is warranted to test higher doses of ketamine for a clinically significant effect., (© 2020 Wiley Periodicals LLC.)

The last report of the World Health Organization (WHO) stated that approximately four million people experience bone pain due to malignant diseases. Among them, metastatic bone pain is one of the most important sources of complaint. The estimated median survival in the presence of bone metastases ranks from 10 to 12 weeks. Bone represents a potential target of distant metastases for the majority of malignant tumours. However, the exact incidence of bone metastases is unknown. Bone metastases have an important socio-economic impact, and due to the enhancement of the overall survivorship, their incidence is increasing. Malignant neoplasms such as lung, thyroid, renal cancer, multiple myeloma, and melanoma often metastasize to the bone. Bone metastases commonly localize to the spinal column, pelvis, shoulder, and distal femur. The proper treatment for painful skeletal metastases is still unknown. Hence, the purpose of this review of the literature was to update current evidence concerning the aetiogenesis, biological behaviour, and treatment algorithms for painful skeletal metastases.

Background & Aims: Pancreatic ductal adenocarcinoma (PDAC) is frequently accompanied by excruciating pain, which has been associated with attraction of cancer cells and their invasion of intrapancreatic sensory nerves. Neutralization of the chemokine CCL2 reduced cancer-associated pain in a clinical trial, but there have been no systematic analyses of the highly diverse chemokine families and their receptors in PDAC., Methods: We performed an open, unbiased RNA-interference screen of mammalian chemokines in co-cultures of mouse PDAC cells (K8484) and mouse peripheral sensory neurons, and confirmed findings in studies of DT8082 PDAC cells. We studied the effects of chemokines on migration of PDAC cell lines. Orthotopic tumors were grown from K8484 cells in mice, and mice were given injections of neutralizing antibodies against chemokines, antagonists, or control antibodies. We analyzed abdominal mechanical hypersensitivity and collected tumors and analyzed them by histology and immunohistochemistry to assess neural remodeling. We collected PDAC samples and information on pain levels from 74 patients undergoing resection and measured levels of CXCR3 and CCR7 by immunohistochemistry and immunoblotting., Results: Knockdown of 9 chemokines in DRG neurons significantly reduced migration of PDAC cells towards sensory neurons. Sensory neuron-derived CCL21 and CXCL10 promoted migration of PDAC cells via their receptors CCR7 and CXCR3, respectively, which were expressed by cells in orthotopic tumors and PDAC specimens from patients. Neutralization of CCL21 or CXCL10, or their receptors, in mice with orthotopic tumors significantly reduced nociceptive hypersensitivity and nerve fiber hypertrophy and improved behavioral parameters without affecting tumor infiltration by T cells or neutrophils. Increased levels of CXCR3 and CCR7 in human PDAC specimens were associated with increased frequency of cancer-associated pain, determined from patient questionnaires., Conclusions: In an unbiased screen of chemokines, we identified CCL21 and CXCL10 as proteins that promote migration of pancreatic cancer cells toward sensory neurons. Inhibition of these chemokines or their receptors reduce hypersensitivity in mice with orthotopic tumors, and patients with PDACs with high levels of the chemokine receptors of CXCR3 and CCR7 had increased frequency of cancer-associated pain., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: Intranasal fentanyl (INF) quickly and noninvasively relieves severe pain, whereas intravenous hydromorphone (IVH) reliably treats severe cancer pain but requires vascular access. The trial evaluated the efficacy of INF relative to IVH for treating cancer patients with severe pain in an emergency department (ED) setting., Methods: We randomized 82 patients from a comprehensive cancer center ED to receive INF (n = 42) or IVH (n = 40). Eligible patients reported severe pain at randomization (≥7, scale: 0 "none" to 10 "worst pain"). We conducted non-inferiority comparisons (non-inferiority margin = 0.9) of pain change from treatment initiation (T0) to one hour later (T60). T0 pain ratings were unavailable; therefore, we estimated T0 pain by comparing 1) T60 ratings, assuming similar group T0 ratings; 2) pain change, estimating T0 pain = randomization ratings, and 3) pain change, with T0 pain = 10 (IVH group) or T0 pain = randomization rating (INF group)., Results: At T60, the upper 90% confidence limit (CL) of the mean log-transformed pain ratings for the INF group exceeded the mean IVH group rating by 0.16 points (>pain). Substituting randomization ratings for T0 pain, the lower 90% CL of mean pain change in the INF group extended 0.32 points below (

Background: Over 70% to 85% of men with advanced prostate cancer (PCa) develop bone metastases characterized by severe bone pain and increased likelihood of bone fracture. These clinical features result in decreased quality of life and act as a predictor of higher mortality. Mechanistically, the skeletal pathologies such as osteolytic lesions and abnormal osteoblastic activity drive these symptoms. The role of immune cells in bone cancer pain remains understudied, here we sought to recapitulate this symptomology in a murine model., Methods: The prostate cancer bone metastasis-induced pain model (CIBP) was established by transplanting a mouse prostate cancer cell line into the femur of immunocompetent mice. Pain development, gait dynamics, and the changes in emotional activities like depression and anxiety were evaluated. Animal tissues including femurs, dorsal root ganglion (DRG), and spinal cord were collected at killing and microcomputed tomography (μCT), histology/immunohistochemistry, and quantitative immunofluorescent analysis were performed., Results: Mice receiving prostate cancer cells showed a significantly lower threshold for paw withdrawal responses induced by mechanical stimulation compared with their control counterparts. Zero maze and DigiGait analyses indicated reduced and aberrant movement associated emotional activity compared with sham control at 8-weeks postinjection. The μCT analysis showed osteolytic and osteoblastic changes and a 50% reduction of the trabecular volumes within the prostate cancer group. Neurologically we demonstrated, increased calcitonin gene-related peptide (CGRP) and neuronal p75 NTR immune-reactivities in both the projected terminals of the superficial dorsal horn and partial afferent neurons in DRG at L2 to L4 level in tumor-bearing mice. Furthermore, our data show elevated nerve growth factor (NGF) and TrkA immunoreactivities in the same segment of the superficial dorsal horn that were, however, not colocalized with CGRP and p75 NTR ., Conclusions: This study describes a novel immunocompetent model of CIBP and demonstrates the contribution of NGF and p75 NTR to chronic pain in bone metastasis., (© 2020 Wiley Periodicals LLC.)

Emerging immune therapy, such as with the anti-programmed cell death-1 (anti-PD-1) monoclonal antibody nivolumab, has shown efficacy in tumor suppression. Patients with terminal cancer suffer from cancer pain as a result of bone metastasis and bone destruction, but how PD-1 blockade affects bone cancer pain remains unknown. Here, we report that mice lacking Pdcd1 (Pd1-/-) demonstrated remarkable protection against bone destruction induced by femoral inoculation of Lewis lung cancer cells. Compared with WT mice, Pd1-/- mice exhibited increased baseline pain sensitivity, but the development of bone cancer pain was compromised in Pd1-/- mice. Consistently, these beneficial effects in Pd1-/- mice were recapitulated by repeated i.v. applications of nivolumab in WT mice, even though nivolumab initially increased mechanical and thermal pain. Notably, PD-1 deficiency or nivolumab treatment inhibited osteoclastogenesis without altering tumor burden. PD-L1 and CCL2 are upregulated within the local tumor microenvironment, and PD-L1 promoted RANKL-induced osteoclastogenesis through JNK activation and CCL2 secretion. Bone cancer upregulated CCR2 in primary sensory neurons, and CCR2 antagonism effectively reduced bone cancer pain. Our findings suggest that, despite a transient increase in pain sensitivity following each treatment, anti-PD-1 immunotherapy could produce long-term benefits in preventing bone destruction and alleviating bone cancer pain by suppressing osteoclastogenesis.

Background: The purpose of this study was to determine generic, cancer-specific, and prostate cancer-specific health-related quality of life (HRQoL), pain and changes over time in patients with metastatic castration-resistant prostate cancer (mCRPC) in daily practice., Patients and Methods: PRO-CAPRI is an observational, prospective study in 10 hospitals in the Netherlands. Patients with mCRPC completed the EQ-5D, European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30), and Brief Pain Inventory-Short Form (BPI-SF) every 3 months and European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire-Prostate Cancer Module (EORTC QLQ-PR25) every 6 months for a maximum of 2 years. Subgroups were identified based on chemotherapy pretreatment. Outcomes were generic, cancer-specific, and prostate cancer-specific HRQoL and self-reported pain. Descriptive statistics were performed including changes over time and minimal important differences (MID) between subgroups., Results: In total, 151 included patients answered 873 questionnaires. The median follow-up from the start of the study was 19.5 months, and 84% were treated with at least 1 life-prolonging agent. Overall, patients were in good clinical condition (Eatern Cooperative Oncology Group performance status 0-1 in 78%) with normal baseline hemoglobin, lactate dehydrogenase, and alkaline phosphatase. At inclusion, generic HRQoL was high with a mean EQ visual analog score of 73.2 out of 100. The lowest scores were reported on role and physical functioning (mean scores of 69 and 76 of 100, respectively), and fatigue, pain, and insomnia were the most impaired domains. These domains deteriorated in > 50% of patients., Conclusion: Although most patients were treated with new treatments during follow-up, mCRPC has a negative impact on HRQoL with deterioration in all domains over time, especially role and physical functioning. These domains need specific attention during follow-up to maintain HRQoL as long as possible by timely start of adequate supportive care management., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Ultrasound-guided pectoral nerve block type II is a recently proposed technique for postoperative analgesia after breast cancer surgery. The thoracic paravertebral block is widely used for this purpose by decades. The presented study compares the efficacy of these two techniques for postoperative analgesia., Materials and Methods: Sixty adult women were undergoing unilateral radical mastectomy or quadrantectomy with axillary dissection. The patients were randomized to receive either pectoral nerve block with 30ml ropivacaine 0.375% (Pecs group) or thoracic paravertebral block with 20ml ropivacaine 0.5% (TPVB group). The evaluated variables included pain intensity by the numerical rating scale at 0, 2, 4, 6, 12, 18 and the 24 hours, 24-hour postoperative opioid (promedol) and nonopioid (ketoprofen) consumption and the time to first rescue analgesia., Results: There were no statistically significant differences between both groups in the pain intensity after surgery. Ten (33%) patients from Pecs group and nine (30%) patients from TPVB group did not require any analgesia within the first 24 hours (P = 0.793). The mean postoperative ketoprofen consumption was lower in Pecs group: 63.3 (± 66.87) mg vs. 90.0 (± 84.49) mg (&#1056; = 0.283). The number of patients who required promedol was 6 (20%) vs. 8 (27%) in Pecs and TPVB groups, respectively (&#1056; = 0.542). The time to first analgesic request was longer in Pecs group, 550 (400.0-600.0) min vs. 510 (360.0-600.0) min (&#1056; = 0.506) in TPVB group., Conclusions: In breast cancer surgery, the pectoral nerve block type II with ropivacaine 0.375% can provide postoperative analgesia that is comparable to the single-level thoracic paravertebral block.

Cancer-induced pain (CIP) is a kind of chronic pain that occurs during cancer progression over time. However, the mechanisms are largely unknown, and clinical treatment remains challenging. LncRNAs have been reported to play critical roles in various biological processes, including chronic pain. The aim of our study was to investigate whether lncRNAs participate in the development of CIP by regulating the expression levels of some molecules related to pain modulation. The CIP model was established by injecting Walker 256 mammary gland tumor cells into the tibial canal of rats. In this study, we found that lncRNA-NONRATT021203.2 was increased in the CIP rats and that lncRNA-NONRATT021203.2-siRNA could relieve hyperalgesia in these rats. For elucidation of the underlying mechanism, we showed that lncRNA-NONRATT021203.2 could target C-X-C motif chemokine ligand 9 (CXCL9), which was increased in the CIP rats, and that CXCL9-siRNA could relieve hyperalgesia. At the same time, silencing lncRNA-NONRATT021203.2 expression decreased the mRNA and protein levels of CXCL9. Immunofluorescence analysis showed that CXCL9 was mainly expressed in the CGRP-positive and IB4-positive DRG neurons. Further research showed that lncRNA-NONRATT021203.2 and CXCL9 were colocalized in the DRG neurons. Our data suggested that lncRNA-NONRATT021203.2 participated in the CIP in rats and likely mediates the upregulation of CXCL9. The present study provided us with a new potential target for the clinical treatment of cancer-induced pain., Competing Interests: Declaration of competing interest The authors declare that they have no conflicts of interest., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background and Objective: Glossopharyngeal nerve block (GNB) technique has been used as alternative of treatment of cancer and noncancer pain of the oral cavity. The objective of the study is to compare the two approaches (extraoral and intraoral) of GNB in patients of carcinoma of the tongue in terms of efficacy, duration, and complications., Materials and Methods: This was a prospective comparative randomized study over a period of 1 year. Fifty patients of either sex of ASA physical status and 2, between 21 and 70 years of age, suffering from carcinoma of the tongue, were selected. The patients were randomly divided into two groups. Group I received 4 mL of 0.5% bupivacaine combined with 40 mg, of triamcinolonacetonide by extraoral approach of GNB, and Group II received the same amount of drug by intraoral approach of GNB. Hemodynamic parameters, degree of pain relief using visual analog scale (VAS), number of attempts, effect on quality of life (QOL), and complication were noted during the performance of GNB., Results: Demographic profile in both groups was comparable. Rate of complication and number of attempts to complete intervention were higher in Group I, which was found to be statistically significant. However, mean VAS scores in Group I were significantly higher as compared to those in Group II during most of the study period starting from the 1 st follow-up at 30 min to the 2 nd month postintervention (P < 0.05). No statistically significant difference in mean QOL scores of two groups was observed for the entire study period except at 1 week when mean scores in Group I were higher as compared to those in Group II (P = 0.011)., Conclusion: The intraoral approach of GNB was better with respect to pain control and improvement in QOL whereas the rate of complication and number of attempts was lower in extraoral approach of GNB., Competing Interests: None

Cancer pain is a common symptom experienced by patients, caused either by the disease or its treatment. Morphine remains the most effective and recommended treatment for cancer pain. However, cancer patients still do not receive appropriate management for their pain, and under-treatment is common. Lack of knowledge and negative attitudes towards cancer pain and analgesia among professionals, patients and family caregivers are reported as one of the most common barriers to effective cancer pain management (CPM). To systematically review research on the nature and impact of attitudes and knowledge towards CPM, a systematic literature search of 6 databases (the Cochrane library, MEDLINE, PsycINFO, CINAHL, Web of Science and EMBASE) was undertaken in July 2018. Additionally, hand-searching of Google, Google Scholar and reference lists was conducted. The inclusion criteria were adult (18-65 years of age), studies which included attitudes and knowledge towards CPM, studies written in English, published literature only and cross-sectional design. Included studies were critically appraised by two researchers independently using the Joanna Briggs Institute Analytical Cross Sectional Studies Assessment (JBI-ACSSA). A total of 36 studies met the inclusion criteria. The main finding was that among professionals, patients, caregivers and the public there were similar attitudinal barriers to effective CPM. The most commonly cited barriers were fear of drug addiction, tolerance of medication and side effects of opioids. We also found differences between professional groups (physicians versus nurses) and between different countries based on their potential exposure to palliative care training and services. There are still barriers to effective CPM, which might result in unrelieved cancer pain. Therefore, more educational programmes and training for professionals on CPM are needed. Furthermore, patients, caregivers, and the public need more general awareness and adequate level of knowledge about CPM.

Pancreatic cancer is often diagnosed due to the patient seeking medical attention for abdominal pain. It is among the most painful cancers, with pain severity strongly correlating with prognosis. Perineural invasion is a prominent feature of pancreatic cancer and often the first route of metastasis resulting in neuropathic pain. While surgical pain is present, it is generally short-lived; chemo- and radio-therapy associated side effect pain is often longer lasting and more difficult to manage. Treatment-induced mucositis in response to chemotherapy occurs throughout the GI tract resulting in infection-prone ulcers on the lip, buccal mucosa, palate or tongue. Cisplatin treatment is associated with axonal neuropathy in the dorsal root ganglion, although other large sensory fibers can be affected. Opioid-induced hyperalgesia can also emerge in patients. Along with traditional means to address pain, neurolytic celiac plexus block of afferent nociceptive fibers has been reported to be effective in 74% of patients. Moreover, as cancer treatments become more effective and result in improved survival, treatment-related side effects become more prevalent. Here, pancreatic cancer and treatment associated pain are reviewed along with current treatment strategies. Potential future therapeutic strategies to target the pathophysiology underlying pancreatic cancer and pain induction are also presented., (Copyright© 2020, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

There is unmet need to design an analgesic with fewer side effects for severe pain management. Although traditional opioids are the most effective painkillers, they are accompanied by severe adverse responses, such as respiratory depression, constipation symptoms, tolerance, withdrawal, and addiction. We indicated BPR1M97 as a dual mu opioid receptor (MOP)/nociceptin-orphanin FQ peptide (NOP) receptor full agonist and investigated the pharmacology of BPR1M97 in multiple animal models. In vitro studies on BPR1M97 were assessed using cyclic-adenosine monophosphate production, β-arrestin, internalization, and membrane potential assays. In vivo studies were characterized using the tail-flick, tail-clip, lung functional, heart functional, acetone drop, von Frey hair, charcoal meal, glass bead, locomotor activity, conditioned place preference (CPP) and naloxone precipitation tests. BPR1M97 elicited full agonist properties for all cell-based assays tested in MOP-expressing cells. However, it acted as a G protein-biased agonist for NOP. BPR1M97 initiated faster antinociceptive effects at 10 min after subcutaneous injection and elicited better analgesia in cancer-induced pain than morphine. Unlike morphine, BPR1M97 caused less respiratory, cardiovascular, and gastrointestinal dysfunction. In addition, BPR1M97 decreased global activity and induced less withdrawal jumping precipitated by naloxone. Thus, BPR1M97 could serve as a novel small molecule dual receptor agonist for antinociception with fewer side effects than morphine. This article is part of the Special Issue entitled 'New Vistas in Opioid Pharmacology'., (Copyright © 2019. Published by Elsevier Ltd.)

Autophagy allows cancer cells to respond changes in nutrient status by degrading and recycling non-essential intracellular contents. Inhibition of autophagy combined with nutrient deprivation is an effective strategy to treat cancer. Pain is a primary determinant of poor quality of life in advanced cancer patients, but there is currently no satisfactory treatment. In addition, effective treatment of cancer does not efficiently relieve cancer pain, but may increase pain in many cases. Hence, few studies focus on simultaneous cancer therapy and pain relief, and made this situation even worse. Method : Ropivacaine was loaded into tumor-active targeted liposomes. The cytotoxicity of ropivacaine-based combination therapy in B16 and HeLa cells were tested. Moreover, a mice model of cancer pain which was induced by inoculation of melanoma near the sciatic nerve was constructed to assess the cancer suppression and pain relief effects of ropivacaine-based combination therapy. Results : Ropivacaine and ropivacaine-loaded liposomes (Rop-DPRL) were novelly found to damage autophagic degradation. Replicated administration of Rop-DPRL and calorie restriction (CR) could efficiently repress the development of tumor. In addition, administration of Rop-DPRL could relieve cancer pain with its own analgestic ability in a short duration, while repeated administration of Rop-DPRL and CR resulted in continuous alleviation of cancer pain through reduction of VEGF-A levels in advanced cancer mice. Further, dual inhibition of phosphorylation of STAT3 at Tyr705 and Ser727 by Rop-DPRL and CR contribute to the reduction of VEGF-A. Conclusion : Combination therapy with Rop-DPRL and nutrient deprivation simultaneously suppresses cancer growth and relieves cancer pain., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Background: Pain may be associated with actinic keratosis (AK), intraepidermal carcinoma (IEC) and invasive squamous cell carcinoma (SCC), which may all display high-risk features., Aim: To examine variation in pain frequency associated with these three conditions, and assess their invasive SCC surface diameter, invasion depth, grade of differentiation, presence of acantholysis and perineural invasion (PNI)., Methods: Pain was prospectively recorded for consecutive cases of AK, IEC and SCC from three institutions in Australia during the period 2016-2018., Results: Pain with palpation was recorded with 15.8% of AK (n = 30/190), 15.1% of IEC (n = 345/299) and 29.0% invasive SCC (n = 247/853). Pain without palpation was respectively 1.1% (2/190), 4.0% (12/299) and 6.7% (57/853). Invasive SCC with increased surface diameters and deeper invasion recorded increased pain frequency. Pain did not vary significantly by the grade of differentiation in males. In females, well-differentiated SCC recorded more pain (45.4%; n = 473) than poorly differentiated SCC (9.1%; n = 11). Acantholytic SCC recorded more pain 48.7% (n = 29) than nonacantholytic SCC 35.2% (n = 824). Three out of five cases of PNI recorded pain. Pain intensity was not recorded, which was a limitation., Conclusion: Pain presence increases from AK to invasive SCC. Pain was more frequent in invasive SCC with increased surface diameter, deeper invasion, acantholysis and PNI. Pain frequency did not vary between the grades of differentiation in males. In females, pain was less frequent in poorly differentiated than in well-differentiated SCC., (© 2019 British Association of Dermatologists.)

Studies have been conducted on adults prescribed with methadone to determine the necessary frequency of QTc monitoring but no consensus has been reached and no similar research has been conducted in the pediatric population. The objective of this retrospective study was to determine the occurrence rate of QTc interval prolongation associated with methadone use in a pediatric oncologic population. In total, 18% of patients developed QTc interval prolongation. These patients had longer baseline QTc intervals and were on more QTc interval-prolonging medications. Our data suggest that these variables may be able to risk stratify patients who require more frequent monitoring.

Head and neck cancers (HNC) represent 5% of all malignancies worldwide with about 180,000 cancer deaths per year. Patients with HNC are characterized by a systemic inflammatory state, generally associated with worse outcomes. Treatment-related toxicity is common among HNC patients and causes systemic consequences such as fatigue or cognitive dysfunction. The therapeutic treatments of HNC involve the release in circulation of inflammatory systemic mediators, whose effects trigger a vicious circle that may lead to functional and behavioral alterations. The areas of the head and neck are highly sensitive to pain. Literature data confirm that in HNC patients, pain is one of the most distressing symptoms across all the phases of treatment. Pain is associated with worse general conditions, depression, fatigue, impaired cognitive functions, and lower survival rate. The treatment of advanced HNC cases is multimodal and requires a multidisciplinary psycho-socio-pharmacological approach mediated by a team of experts. The pharmacological approach in management of HNC patients with pain is fundamental and involves the use of opioids, NSAIDs, steroids, or other drugs. Opioids in pain management therapy in patients with HNC could allow the pain level to be adequately monitored, thus improving quality of life. The integration of opioid and non-opioid therapy as well as non-pharmacological interventions is essential for the rehabilitation of physical, social, and psychological functions and to achieve pain control in patients with HNC. Opioid treatment is the mainstay for pain control, being used both for background and breakthrough cancer pain (BTcP) episodes. Fentanyl, easily absorbed and generally well tolerated, appears to be a possible choice due to its versatility. Non-pharmacological interventions, such as tailored yoga, physical exercise, and acupuncture, may have a role in pain management in patients with HNC.

Purpose of Review: This systematic review and meta-analysis aimed to synthesize the evidence on the effects of psychosocial interventions on pain in advanced cancer patients., Recent Findings: The included studies investigated the effects of relaxation techniques, cognitive-behavioral therapy, music therapy, mindfulness- and acceptance-based interventions, and supportive-expressive group therapy. Overall, we found a small, but significant effect on pain intensity (d = - 0.29, CI = - 0.54 to - 0.05). Effect sizes were highly heterogeneous between studies. We did not find evidence for the superiority of any of the intervention types. However, psychosocial interventions may be more effective if they specifically targeted pain distress as the primary outcome. Although findings were mixed, psychosocial interventions can be recommended to complement comprehensive care to alleviate pain in patients facing an advanced or terminal stage of the disease. Future research should develop innovative interventions tailored specifically for pain relief.