Sex-Specific Differences in Toxicity Following Systemic Paclitaxel Treatment and Localized Cardiac Radiotherapy.

The impact of sex in the development of long-term toxicities affecting the quality of life of cancer survivors has not been investigated experimentally. To address this issue, a series of neurologic and cardiologic endpoints were used to investigate sex-based differences triggered by paclitaxel treatment and radiotherapy exposure. Male and female wild-type (WT) mice were treated with paclitaxel (150 and 300 mg/kg) administered weekly over 6 weeks or exposed to 19 Gy cardiac irradiation. Cohorts were analyzed for behavioral and neurobiologic endpoints to assess systemic toxicity of paclitaxel or cardiovascular endpoints to assess radiotherapy toxicity. Interestingly, female WT mice exhibited enhanced tolerance compared to male WT mice regardless of the treatment regimen. To provide insight into the possible sex-specific protective mechanisms, rhoB-deficient animals and elderly mice (22 months) were used with a focus on the possible contribution of sex hormones, including estrogen. In females, RhoB deficiency and advanced age had no impact on neurocognitive impairment induced by paclitaxel but enhanced cardiac sensitivity to radiotherapy. Conversely, rhoB-deficiency protected males from radiation toxicity. In sum, RhoB was identified as a molecular determinant driving estrogen-dependent cardioprotection in female mice, whereas neuroprotection was not sex hormone dependent. To our knowledge, this study revealed for the first time sex- and organ-specific responses to paclitaxel and radiotherapy.

Extraskeletal Myxoid Chondrosarcoma of the Vulva Confirmed by EWSR1 FISH: A Case Report and Review of the Literature.

Extraskeletal myxoid chondrosarcoma of the vulva is a very rare tumor, with less than 10 cases reported in the literature. We report a case of a 45-yr-old woman with extraskeletal myxoid chondrosarcoma of the vulva confirmed by EWSR1 fluorescence in situ hybridization. Given the unusual site and prominent myxoid morphology, a broad differential diagnosis and a variety of ancillary testing was required. This article aims to review extraskeletal myxoid chondrosarcoma of the vulva, the differential diagnosis of a myxoid spindle cell neoplasm of the vulva, and the diagnostic importance of immunohistochemistry and EWSR1 fluorescence in situ hybridization.

Plagiochiline A Inhibits Cytokinetic Abscission and Induces Cell Death.

We previously reported on the isolation and biological activities of plagiochiline A (1), a 2,3-secoaromadendrane-type sesquiterpenoid from the Peruvian medicinal plant, Plagiochila disticha. This compound was found to have antiproliferative effects on a variety of solid tumor cell lines, as well as several leukemia cell lines. Other researchers have also noted the cytotoxicity of plagiochiline A (isolated from different plant species), but there are no prior reports regarding the mechanism for this bioactivity. Here, we have evaluated the effects of plagiochiline A on cell cycle progression in DU145 prostate cancer cells. A cell cycle analysis indicated that plagiochiline A caused a significant increase in the percentage of cells in the G2/M phase when compared with control cells. When cells were stained and observed by fluorescence microscopy to examine progress through the mitotic phase, we found a significant increase in the proportion of cells with features of late cytokinesis (cells connected by intercellular bridges) in the plagiochiline A-treated samples. These results suggest that plagiochiline A inhibits cell division by preventing completion of cytokinesis, particularly at the final abscission stage. We also determined that plagiochiline A reduces DU145 cell survival in clonogenic assays and that it induces substantial cell death in these cells.

N-(3-Oxo-acyl)-homoserine lactone induces apoptosis primarily through a mitochondrial pathway in fibroblasts.

N-(3-Oxododecanoyl)-l-homoserine lactone (C12) is produced by Pseudomonas aeruginosa to function as a quorum-sensing molecule for bacteria-bacteria communication. C12 is also known to influence many aspects of human host cell physiology, including induction of cell death. However, the signalling pathway(s) leading to C12-triggered cell death is (are) still not completely known. To clarify cell death signalling induced by C12, we examined mouse embryonic fibroblasts deficient in "initiator" caspases or "effector" caspases. Our data indicate that C12 selectively induces the mitochondria-dependent intrinsic apoptotic pathway by quickly triggering mitochondrial outer membrane permeabilisation. Importantly, the activities of C12 to permeabilise mitochondria are independent of activation of both "initiator" and "effector" caspases. Furthermore, C12 directly induces mitochondrial outer membrane permeabilisation in vitro. Overall, our study suggests a mitochondrial apoptotic signalling pathway triggered by C12, in which C12 or its metabolite(s) acts on mitochondria to permeabilise mitochondria, leading to activation of apoptosis.

The toll-like receptor 2 agonist Pam3CSK4 is neuroprotective after spinal cord injury.

Microglia/macrophage activation and recruitment following spinal cord injury (SCI) is associated with both detrimental and reparative functions. Stimulation of the innate immune receptor Toll-like receptor-2 (TLR2) has shown to be beneficial following SCI, and it increases axonal regeneration following optic nerve crush. However, the mechanism(s) remain unclear. As microglia express high levels of TLR2, we hypothesized that modulating the microglial response to injury using a specific TLR2 agonist, Pam3CSK4, would prevent secondary-mediated white matter degeneration following SCI. To test this hypothesis, we documented acute changes in microglia, axons, and oligodendroglia over time using two-photon excitation and an ex vivo laser-induced SCI (LiSCI) model. We utilized double transgenic mice that express GFP in either microglia or oligodendroglia, and YFP in axons, and we applied the lipophilic fluorescent dye (Nile Red) to visualize myelin. We found that treatment with Pam3CSK4 initiated one hour after injury induced a significant increase in the extent and timing of the microglial response to injury compared to vehicle controls. This enhanced response was observed 2 to 4h following SCI and was most prominent in areas closer to the ablation site. In addition, Pam3CSK4 treatment significantly reduced axonal dieback rostral and caudal to the ablation at 6h post-SCI. This protective effect of Pam3CSK4 was also mirrored when assessing secondary bystander axonal damage (i.e., axons spared by the primary injury that then succumb to secondary degeneration), and when assessing the survival of oligodendroglia. Following these imaging experiments, custom microarray analysis of the ex vivo spinal cord preparations revealed that Pam3CSK4-treatment induced an alternative (mixed M1:M2) microglial activation profile. In summary, our data suggest that by providing a second "sterile" activation signal to microglia through TLR2/TLR1 signaling, the microglial response to injury can be modulated in situ and is highly neuroprotective.

N-(3-oxo-acyl) homoserine lactone inhibits tumor growth independent of Bcl-2 proteins.

Pseudomonas aeruginosa produces N-(3-oxododecanoyl)-homoserine lactone (C12) as a quorum-sensing molecule for bacterial communication. C12 has also been reported to induce apoptosis in various types of tumor cells. However, the detailed molecular mechanism of C12-triggerred tumor cell apoptosis is still unclear. In addition, it is completely unknown whether C12 possesses any potential therapeutic effects in vivo. Our data indicate that, unlike most apoptotic inducers, C12 evokes a novel form of apoptosis in tumor cells through inducing mitochondrial membrane permeabilization independent of both pro- and anti-apoptotic Bcl-2 proteins. Importantly, C12 inhibits tumor growth in animals regardless of either pro- or anti-apoptotic Bcl-2 proteins. Furthermore, opposite to conventional chemotherapeutics, C12 requires paraoxonase 2 (PON2) to exert its cytotoxicity on tumor cells in vitro and its inhibitory effects on tumor growth in vivo. Overall, our results demonstrate that C12 inhibits tumor growth independent of both pro- and anti-apoptotic Bcl-2 proteins, and through inducing unique apoptotic signaling mediated by PON2 in tumor cells.

An ex vivo laser-induced spinal cord injury model to assess mechanisms of axonal degeneration in real-time.

Injured CNS axons fail to regenerate and often retract away from the injury site. Axons spared from the initial injury may later undergo secondary axonal degeneration. Lack of growth cone formation, regeneration, and loss of additional myelinated axonal projections within the spinal cord greatly limits neurological recovery following injury. To assess how central myelinated axons of the spinal cord respond to injury, we developed an ex vivo living spinal cord model utilizing transgenic mice that express yellow fluorescent protein in axons and a focal and highly reproducible laser-induced spinal cord injury to document the fate of axons and myelin (lipophilic fluorescent dye Nile Red) over time using two-photon excitation time-lapse microscopy. Dynamic processes such as acute axonal injury, axonal retraction, and myelin degeneration are best studied in real-time. However, the non-focal nature of contusion-based injuries and movement artifacts encountered during in vivo spinal cord imaging make differentiating primary and secondary axonal injury responses using high resolution microscopy challenging. The ex vivo spinal cord model described here mimics several aspects of clinically relevant contusion/compression-induced axonal pathologies including axonal swelling, spheroid formation, axonal transection, and peri-axonal swelling providing a useful model to study these dynamic processes in real-time. Major advantages of this model are excellent spatiotemporal resolution that allows differentiation between the primary insult that directly injures axons and secondary injury mechanisms; controlled infusion of reagents directly to the perfusate bathing the cord; precise alterations of the environmental milieu (e.g., calcium, sodium ions, known contributors to axonal injury, but near impossible to manipulate in vivo); and murine models also offer an advantage as they provide an opportunity to visualize and manipulate genetically identified cell populations and subcellular structures. Here, we describe how to isolate and image the living spinal cord from mice to capture dynamics of acute axonal injury.

Physangulidines A, B, and C: three new antiproliferative withanolides from Physalis angulata L.

Bioassay-directed fractionation of the whole plant of Physalis angulata L. afforded three new antiproliferative withanolides with an unusual carbon framework: physangulidines A (1), B (2), and C (3). Structures of the three isomeric withanolides were determined by a combination of HRMS, NMR spectroscopic, and X-ray crystallographic methods. Each has shown significant antiproliferative activity against DU145 prostate cancer cells. Physangulidine A (1) was further tested against a wide range of additional cancer cell lines and found to exhibit significant antiproliferative activity.

Cytotoxic and anti-infective sesquiterpenes present in Plagiochila disticha (Plagiochilaceae) and Ambrosia peruviana (Asteraceae).

A pharmacological screening of the ethanol extract and fractions of two Peruvian medicinal plants, Plagiochila disticha and Ambrosia peruviana, led to the isolation and characterization of three ENT-2,3-secoaromadendrane-type sesquiterpenoids, named plagiochiline A ( 1), I ( 2), and R ( 3), as well as of two pseudoguaianolids, damsin ( 4) and confertin ( 5), which exhibited significant cytotoxic activity against a panel of human tumor cell lines. Compounds 1, 4, and 5 were also investigated for their in vitro antileishmanial, trypanocidal, and antituberculosis activity against Leishmania amazonensis axenic amastigotes and Trypanosoma cruzi trypomastigotes, as well as against MDR and sensitive strains of Mycobacterium tuberculosis, respectively.