minocycline and Bone-Neoplasms

Anxiety and depression induced by cancer-related pain disturb quality of life and willingness to survive. As a component of the limbic system, the basolateral amygdala (BLA) is critical for processing negative emotions. The reactive microglial engulfment of synapses may promote depression during adolescence. However, whether microglia phagocytose synapses to mediate cancer pain-induced depression remains unclear. The present study established a bone cancer-pain model to investigate the association between dendritic spine synapses and depressive-like behavior and explore the phagocytic function of microglia in the BLA. We found that tumor-bearing mice experienced postoperative pain-related depression, and their BLAs exhibited reactive microglia, as well as phagocytic synapses. The microglial inhibitor minocycline effectively mitigated depressive behavior, synaptic damage, and the phagocytic function of microglia. Our study implicates microglia-mediated synaptic loss in the BLA may act as the pathological basis of depressive-like behavior in bone cancer pain model.

Topics: Animals; Basolateral Nuclear Complex; Bone Neoplasms; Cancer Pain; Mice; Microglia; Minocycline; Quality of Life

Pain and depression are highly prevalent symptoms in cancer patients. They tend to occur simultaneously and affect each other and share biological pathways and neurotransmitters. In this study, we investigated the roles of microglia in the hippocampus in the comorbidity of bone cancer pain and depressive-like behaviors in an animal model of bone cancer pain.. Bone cancer pain was induced by injection of Walker 256 mammary gland carcinoma cells into the tibia of rats. The effects of intracerebroventricular administration of microglia inhibitor minocycline were examined.. Carcinoma intratibia injection caused comorbidity of mechanical allodynia and depressive-like behaviors in rats and activation of microglia in the hippocampus. Both mechanical allodynia and depressive-like behaviors were attenuated by minocycline. Enzyme-linked immunosorbent assay analysis showed that the enhanced expressions of M1 microglia marker (CD 86) and the proinflammatory cytokines tumor necrosis factor-α and interleukin-1β in the hippocampus of cancer-bearing rats were decreased by minocycline. On the other hand, minocycline also increased the expressions of M2 microglia marker (MRC1) and anti-inflammatory cytokine interleukin-10.. The results suggest that the activation of microglia in the hippocampus plays an important role in the development of pain and depressive-like behaviors in bone cancer condition.

Topics: Animals; Bone Neoplasms; Cancer Pain; Depression; Female; Hippocampus; Inflammation Mediators; Injections, Intraventricular; Microglia; Minocycline; Rats; Rats, Wistar

Activation of spinal cord microglia is crucial for the development of bone cancer pain (BCP). The essential signal between neuronal excitability and microglial activation is not fully understood. In the present study, carcinoma implantation into tibia was used to induce BCP and RNAi-lentivirus was injected into spinal cord to knock down C1, C2 or C3 of complement cascade. We showed that C1, C2 and C3 co-localized in the same neurons and increased in cancer-bearing rats along with microglial activation. Knocked down of C1, C2 or C3 inhibited microglial activation and prevented the development of cancer-induced bone pain. Intrathecal administration of either minocycline (an inhibitor of microglial activity) to inhibit the activation of microglia or compstatin (a C3-targeted complement inhibitor) to block the complement cascade reversed cancer induced bone pain. Further study indicated that neuronal complement promoted the activation of microglia via complement 3 receptor (C3R). In the in vitro experiments, the proliferation of microglia was enhanced by the activation product of C3 (iC3b), but was inhibited by compstatin. These results indicated that neuronal complement pathway promoted the activation of microglia via C3R and contributed to the development of BCP.

Topics: Animals; Bone Neoplasms; Cancer Pain; Cell Line, Tumor; Complement C3; Female; Hyperalgesia; Macrophage-1 Antigen; Mammary Neoplasms, Experimental; Microglia; Minocycline; Neurons; Peptides, Cyclic; Rats; Rats, Sprague-Dawley; Signal Transduction; Spinal Cord; Up-Regulation

To investigate the mechanisms underlying the anti-nociceptive effect of minocycline on bone cancer pain (BCP) in rats.. A rat model of BCP was established by inoculating Walker 256 mammary carcinoma cells into tibial medullary canal. Two weeks later, the rats were injected with minocycline (50, 100 μg, intrathecally; or 40, 80 mg/kg, ip) twice daily for 3 consecutive days. Mechanical paw withdrawal threshold (PWT) was used to assess pain behavior. After the rats were euthanized, spinal cords were harvested for immunoblotting analyses. The effects of minocycline on NF-κB activation were also examined in primary rat astrocytes stimulated with IL-1β in vitro.. BCP rats had marked bone destruction, and showed mechanical tactile allodynia on d 7 and d 14 after the operation. Intrathecal injection of minocycline (100 μg) or intraperitoneal injection of minocycline (80 mg/kg) reversed BCP-induced mechanical tactile allodynia. Furthermore, intraperitoneal injection of minocycline (80 mg/kg) reversed BCP-induced upregulation of GFAP (astrocyte marker) and PSD95 in spinal cord. Moreover, intraperitoneal injection of minocycline (80 mg/kg) reversed BCP-induced upregulation of NF-κB, p-IKKα and IκBα in spinal cord. In IL-1β-stimulated primary rat astrocytes, pretreatment with minocycline (75, 100 μmol/L) significantly inhibited the translocation of NF-κB to nucleus.. Minocycline effectively alleviates BCP by inhibiting the NF-κB signaling pathway in spinal astrocytes.

Topics: Analgesics; Animals; Anti-Bacterial Agents; Astrocytes; Bone Neoplasms; Cancer Pain; Cell Line, Tumor; Female; Hyperalgesia; Minocycline; NF-kappa B; Rats, Wistar; Signal Transduction; Spinal Cord

Accumulating evidence suggests that activation of spinal microglia contributes to the development of inflammatory and neuropathic pain. However, the role of spinal microglia in the maintenance of chronic pain remains controversial. Bone cancer pain shares features of inflammatory and neuropathic pain, but the temporal activation of microglia and astrocytes in this model is not well defined. Here, we report an unconventional role of spinal microglia in the maintenance of advanced-phase bone cancer pain in a female rat model. Bone cancer elicited delayed and persistent microglial activation in the spinal dorsal horn on days 14 and 21, but not on day 7. In contrast, bone cancer induced rapid and persistent astrocytic activation on days 7-21. Spinal inhibition of microglia by minocycline at 14 d effectively reduced bone cancer-induced allodynia and hyperalgesia. However, pretreatment of minocycline in the first week did not affect the development of cancer pain. Bone cancer increased ATP levels in CSF, and upregulated P2X7 receptor, phosphorylated p38, and IL-18 in spinal microglia. Spinal inhibition of P2X7/p-38/IL-18 pathway reduced advanced-phase bone cancer pain and suppressed hyperactivity of spinal wide dynamic range (WDR) neurons. IL-18 induced allodynia and hyperalgesia after intrathecal injection, elicited mechanical hyperactivity of WDR neurons in vivo, and increased the frequency of mEPSCs in spinal lamina IIo nociceptive synapses in spinal cord slices. Together, our findings demonstrate a novel role of microglia in maintaining advanced phase cancer pain in females via producing the proinflammatory cytokine IL-18 to enhance synaptic transmission of spinal cord nociceptive neurons.

Topics: Adenosine Triphosphate; Animals; Bone Neoplasms; Excitatory Postsynaptic Potentials; Female; Interleukin-18; Microglia; Miniature Postsynaptic Potentials; Minocycline; Neuralgia; p38 Mitogen-Activated Protein Kinases; Posterior Horn Cells; Rats; Rats, Wistar; Receptors, Purinergic P2X7

Cancer-induced bone pain (CIBP) is a common clinical problem in breast cancer patients with bone metastasis. Recent studies shows chemokines are novel targets for treatment of CIBP. In this study, we intra-tibial inoculated with Walker 256 rat mammary gland carcinoma cells into rat bone to established metastatic breast cancer. Then we measured the expression of CXCL10 in the spinal cord of metastatic bone cancer rats, investigated the role of CXCL10 in the development of CIBP, and the underlying mechanism. Results revealed that after intra-tibial inoculation with Walker 256 cells, rats showed up-regulation of CXCL10 and its receptor CXCR3 in the spinal cord. Interestingly, intrathecally injection of recombinant CXCL10 protein induced mechanical allodynia in naïve rats. Blocking the function of CXCL10/CXCR3 pathway via anti-CXCL10 antibody or CXCR3 antagonist prevented the development of CIBP and microglial activation. Moreover, CXCL10-induced mechanical allodynia was rescued by minocycline treatment during the late-stage of CIBP, days 10-14. The regulation of CXCL10 expression involved microglial activation in a manner of autocrine positive feedback. These results suggest that CXCL10 may be a necessary algogenic molecule, especially in the development of CIBP. Its function was partly mediated via spinal microglial activation. This study provides a novel insight into the biological function of chemokine CXCL10 in the molecular mechanism underlying cancer pain. It also provides new target for clinical treatment of metastatic breast cancer-induced bone pain in future.

Topics: Animals; Anti-Bacterial Agents; Bone Neoplasms; Carcinoma 256, Walker; Chemokine CXCL10; Disease Models, Animal; Female; Gene Expression Regulation, Neoplastic; Hyperalgesia; Interferon-gamma; Mammary Neoplasms, Experimental; Microglia; Minocycline; Musculoskeletal Pain; Pain Threshold; Rats; Rats, Sprague-Dawley; Receptors, CXCR3; Spinal Cord

Topics: Animals; Anti-Bacterial Agents; Bone Neoplasms; Brain-Derived Neurotrophic Factor; Female; Minocycline; Pain; Pain Threshold; Spinal Cord

Previous studies have suggested that the release of brain-derived neurotrophic factor (BDNF) from microglia in spinal cord is necessary for maintaining pain hypersensitivity after nerve injury. However, little is known about its role in cancer-induced bone pain (CIBP), which is in some ways unique. This study demonstrates a critical role of minocycline (a potent inhibitor of microglial activation)-modulated BDNF in the induction and maintenance of behavioral hypersensitivity in a rat model of CIBP. We assessed mechanical threshold and spontaneous pain of CIBP rats. Moreover, minocycline was administered intrathecally from day 4 to day 6 (early stage) or from day 10 to day 12 (later stage), after carcinoma cell inoculation. Real-time PCR, Western blots, and double immunofluorescence were used to detect the expression of OX-42 (marker of activated microglia), phosphorylated p38-MAPK (p-p38), and BDNF. We found that intrathecal minocycline could prevent CIBP at an early stage of tumor growth (from day 4 to day 6). However, at the late stage (from day 10 to day 12), intrathecal minocycline had no effect. Moreover, the expression of OX-42 and BDNF under CIBP, peaking on day 6, were all reduced after minocycline injection from day 4 to day 6. The ability of minocycline-induced reduction of BDNF in the induction of behavioral hypersensitivity could provide an opportunity for alleviating CIBP.

Topics: Animals; Anti-Bacterial Agents; Behavior, Animal; Bone Neoplasms; Brain-Derived Neurotrophic Factor; Female; Hyperalgesia; Microglia; Minocycline; p38 Mitogen-Activated Protein Kinases; Pain; Pain Measurement; Pain Threshold; Phosphorylation; Rats; Rats, Sprague-Dawley; Spinal Cord

To investigate the effect of minocycline hydrochloride ointment on cell attachment and proliferation on titanium disks.. Commercially pure (grade 4) machined titanium discs with three different kinds of surfaces (smooth, acid-etched and sandblasted combined with acid-etched) were treated with minocycline ointment for 1 week, and then cleaned in ultrasonic cleanser for 10 minutes. Surface properties were examined by scanning electron microscope (SEM) and roughness tester before and after the treatment. Surface roughness was compared by paired t test. MG-63 (human osteoblast-like osteosarcoma cell) cells were seeded on these three kinds of discs with or without minocycline treatment, and methl thiazolyl tetrazolium (MTT) was performed to investigate the attachment in the 1st day and proliferation in the 4th and 7th day. Data were analyzed by double factor analysis of variance.. Surface roughness before and after minocycline application was as follows, Smooth: (0.093 ± 0.025) µm, (0.086 ± 0.026) µm; Acid-etched: (1.100 ± 0.095) µm, (1.009 ± 0.196) µm; Sandblasted combined with acid-etched: (2.837 ± 0.283) µm, (2.968 ± 0.206) µm. No significant changes in roughness were found before and after minocycline application (P values were 0.118, 0.436 and 0.692). SEM examination revealed as similar surface configuration after minocycline application as before, except for some remnant of the minocycline ointment in acid-etched and sandblasted combined acid-etched groups. In MTT test, the growth of MG-63 cells in the 1 st, 4th day and 7th day was not different between groups with and without minocycline application (P values were 0.450, 0.848 and 0.835), and among three groups of different surface (P values were 0.184, 0.579 and 0.331).. Minocycline hydrochloride ointment did not affect the surface configuration, surface roughness or the properties for cell attachment and proliferation of titanium discs.

Topics: Acid Etching, Dental; Bone Neoplasms; Cell Adhesion; Cell Line, Tumor; Cell Proliferation; Humans; Microscopy, Electron, Scanning; Minocycline; Ointments; Osteoblasts; Osteosarcoma; Surface Properties; Titanium

Breast carcinomas show a trend toward bone metastasis that is prevalent worldwide. Celecoxib (CX) and minocycline hydrochloride (MH) have both been widely used in treating breast cancer; however, their combined effects on the osseous metastasis of breast cancer have not yet been studied. In the present study, breast cancer cells were injected into the back of the femoral bone of nude mice, and CX and MH were intraperitoneally administered every other day at doses of 30 and 40 mg/kg/day, respectively, for 30 days. Tumor weights and volumes were significantly lower and the tumor inhibition rate was significantly higher in the CX + MH group than those of the control and CX or MH alone groups (p < 0.05). The cell density in the tumor tissue was significantly decreased and apoptotic and necrotic cell death was significantly increased in the CX + MH group, as compared with those of the control and CX or MH alone groups. Microvessel density and expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinase (MMP)-9 in the tumor tissues of the CX + MH group were significantly lower than those of the CX, MH, and control groups. The serum alkaline phosphatase level of the CX + MH group was significantly lower than those of the other groups (p < 0.01). These results suggest that a combined use of CX and MH has better inhibitory effects on the osseous metastasis of breast cancer, as compared to CX or MH alone. They exerted their combined effects by increasing tumor-cell death and decreasing the tumor expression of MMP-9 and VEGF systems.

Topics: Alkaline Phosphatase; Animals; Apoptosis; Body Weight; Bone Neoplasms; Breast Neoplasms; Celecoxib; Cell Line, Tumor; Cyclooxygenase Inhibitors; Drug Therapy, Combination; Female; Humans; Matrix Metalloproteinase 9; Mice; Mice, Inbred Strains; Mice, Nude; Minocycline; Pyrazoles; Sulfonamides; Tumor Burden; Vascular Endothelial Growth Factor A; Xenograft Model Antitumor Assays

Bone metastases are a common complication in prostate and breast cancer patients. It leads to extensive morbidity and eventually mortality. Matrix metalloproteinases are implicated in various steps of development of metastasis, through their ability to degrade the extracellular matrix. Increased matrix metalloproteinase activity of tumor cells has been associated with a higher metastatic potential. Inhibitors of metalloproteinases have been shown to effectively reduce or prevent the formation of metastases. The family of tetracyclines is able to inhibit matrix metalloproteinase activity through chelation of the zinc ion at the active site of the enzyme. Using tumor cell lines relevant to bone metastases, i.e. PC-3, MDA-MB-231, Hs696, B16/F1, we showed that tetracycline and derivatives of tetracycline, namely doxycycline and minocycline, also induced cytotoxicity. The effective concentrations are relatively high for plasma, but are clinically achievable in the bone, since tetracyclines are osteotropic. All four bone-metastasizing tumor cells produced and secreted various matrix metalloproteinases. Doxycycline was able to inhibit the activity of 72- and 92-kDa type IV collagenase secreted by bone-metastasizing cells by 79-87%. These characteristics could make tetracycline a unique candidate as a therapeutic agent to prevent bone metastases in cancer patients with a high likelihood for development of bone metastasis. Studies using animal models of experimental bone metastasis will be necessary to confirm this.

Topics: Adenocarcinoma; Animals; Anti-Bacterial Agents; Blotting, Western; Bone Neoplasms; Breast Neoplasms; Cell Survival; Collagenases; Culture Media, Conditioned; Doxycycline; Extracellular Matrix; Gelatinases; Humans; Male; Matrix Metalloproteinase 1; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; Melanoma; Metalloendopeptidases; Mice; Minocycline; Prostatic Neoplasms; Protease Inhibitors; Tetracycline; Tetracyclines; Tumor Cells, Cultured