Immunomodulator Imiquimod Research Articles

GDF15 promotes glioma stem cell-like phenotype via regulation of ERK1/2\u2013c-Fos\u2013LIF signaling

Growth differentiation factor 15 (GDF15), a member of the transforming growth factor β family, is associated with tumor progression, metastasis, and cell apoptosis. However, controversy persists regarding the role of GDF15 in different tumor types, and its function in glioma stem cells (GSCs) remains unknown. Here, we report that GDF15 promotes the GSC-like phenotype in GSC-like cells (GSCLCs) through the activation of leukemia inhibitor factor (LIF)–STAT3 signaling. Mechanistically, GDF15 was found to upregulate expression of the transcription factor c-Fos, which binds to the LIF promoter, leading to enhanced transcription of LIF in GSCLCs. Furthermore, GDF15 may activate the ERK1/2 signaling pathway in GSCLCs, and the upregulation of LIF expression and the GSC-like phenotype was dependent on ERK1/2 signaling. In addition, the small immunomodulator imiquimod induced GDF15 expression, which in turn activated the LIF–STAT3 pathway and subsequently promoted the GSC-like phenotype in GSCLCs. Thus, our results demonstrate that GDF15 can act as a proliferative and pro-stemness factor for GSCs, and therefore, it may represent a potential therapeutic target in glioma treatment.

Selectively targeting tumor-associated macrophages and tumor cells with polymeric micelles for enhanced cancer chemo-immunotherapy

Tumor-associated macrophage (TAM)-related immunotherapy is a greatly promising strategy that involves altering the immunosuppressive tumor microenvironment with the immunomodulator imiquimod (R837) for enhanced cancer therapy. However, the function of R837 is seriously limited due to poor water solubility and a lack of targeting ability. Here, we developed two types of targeting polymer micelles to separately deliver R837 and the anticancer drug doxorubicin (DOX) to TAMs and tumor cells via intratumoral injection and intravenous injection, respectively, for enhanced cancer chemo-immunotherapy against breast cancer. After these micelles accumulated in the tumor tissues, the immunostimulating micelles released R837, which bound to the TLR-7 receptor on the lysosomal membrane within the TAM, stimulating the maturation of the TAM, thereby causing an antitumor immune response and relieving the immunosuppressive effect in the tumor microenvironment. Simultaneously, the chemotherapeutic micelles released DOX in the cytoplasm of the tumor cells, directly inducing cell death. As a result, a synergistic combination of chemotherapy and immunotherapy was achieved through these nanomedicines, which separately activated the antitumor immune response and inhibited tumor cell growth. Therefore, this strategy is a new avenue for the development of targeting nanomedicines for combination chemo-immunotherapy against malignant cancer.

Novel imiquimod nanovesicles for topical vaccination.

Development of needle and pain free noninvasive immunization procedures is a top priority for public health agencies. In this work the topical adjuvant activity of the immunomodulator imiquimod (IMQ) carried by ultradeformable archaeosomes (UDA2) (nanovesicles containing sn-2,3 ether linked phytanyl saturated archaeolipids) was surveyed and compared with that of ultradeformable liposomes lacking archaeolipids (UDL2) and free IMQ, using the model antigen ovalbumin and a seasonal influenza vaccine in Balb/c mice. UDA2 (250 ± 94 nm, -26 ± 4 mV Z potential) induced higher IMQ accumulation in human skin and higher production of TNF-α and IL-6 by macrophages and keratinocytes than free IMQ and UDL2. Mixed with ovalbumin, UDA2 was more efficient at generating cellular response, as measured by an increase in serum IgG2a and INF-γ production by splenocytes, compared with free IMQ and UDL2. Moreover, mixed with a seasonal influenza vaccine UDA2 produced same IgG titers and IgG2a/IgG1 isotypes ratio (≈1) than the subcutaneously administered influenza vaccine. Topical UDA2 however, induced highest stimulation index and INF-γ levels by splenocytes. UDA2 might be a promising adjuvant for topical immunization, since it produced cell-biased systemic response with ≈ 13-fold lower IMQ dose than the delivered as the commercial IMQ cream, Aldara.

Paget's disease of the vulva treated with imiquimod: case report and review of the literature

Background: Extramammary Paget's disease of the vulva (EPDV) is a rare adenocarcinoma in situ of the vulvar skin and is often resected with involved margins due to its reticular growth pattern. Adjuvant treatment with the immunomodulator imiquimod may be suitable to avoid repeated and mutilating surgery.

Microscopically Controlled Surgery

I am a co-author of the S2k-guideline on basal cell carcinoma (BCC), which is in its final stages of development. Supported by 40 years’ experience in tumor surgery on facial skin and by long-term analyses of more than 3800 operations for facial BCC, my views differ somewhat from those expressed in the article. Hedgehog signaling pathway inhibitors allow a new therapeutic principle in BCC. Because of their short time of use, however, many questions remain open. In the guideline indications are defined for so extensive and metastatic cases of BCC, which therefore can be neither treated by radiation nor by surgery. — A tumor board decides on their use. Competent surgeons and radiologists are a mandatory on such a board. Non-surgical local therapies (laser, cryotherapy, immunomodulators imiquimod, 5-fluorouracil, photodynamic therapy) are reserved for individual cases because of barely predictable oncological and esthetic results. Local recurrences or residual tumors occur in more than 10% of cases after such treatments. For the surgery that is potentially required subsequently, these cause problems regarding R0 resection because of multilocal and poorly localizable tumor residues. According to the guideline, the surgical approach with the highest possible degree of control of the resection margin (Microscopically controlled surgery- MCS) is the method of choice. Compared with conventional surgery, MCS lowers the recurrence rate in primary BCC by only 1% and thus does not significantly improve the prognosis. When treating tumor recurrences, MCS reduces the recurrence rate from 12% to 2.4%. According to my own analyses, surgical treatment for BCC by means of MCS using plastic-surgical or rare epithetic defect repairs on the face, will—in primary BCC—yield a probability for 20 tumor-free years of 98.2%; in the treatment of recurrences in a retrospective analysis of 74%; and in a prospective analysis, consistenly using our variant of MCS, of 98%. Untreated R1 results lower this probability of success drastically, to 52% (primary BCC) and 29% (BCC recurrence). This confirms the validity of the R1 finding for tumor clearance. It does not affect survival. Diverse methods for reconstructions of the defects in the repertoire of maxillofacial surgeons in association with MCS allow a high degree of oncological certainty even in extensive BCC in combination with good esthetic results, even in the problematic facial region.

Recalcitrant Pseudotumoral Anogenital Herpes Simplex Virus Type 2 in HIV-Infected Patients: Evidence for Predominant B-Lymphoplasmocytic Infiltration and Immunomodulators as Effective Therapeutic Strategy

In patients with human immunodeficiency virus (HIV) infection, genital herpetic lesions may be extensive and tend to persist for longer periods; in addition, atypical hypertrophic, ulcerative, or pseudotumor forms have been reported, frequently showing resistance to acyclovir (ACV) treatment. Between 2003 and 2011, 10 HIV-1-infected patients presenting with chronic pseudotumoral anogenital herpes simplex type 2 (HSV-2) infections were studied. All patients developed chronic, hypertrophic HSV-2 anogenital lesions with multilesional presentation in 7 cases and involvement of 2 anatomical sites in 6 of them. At the time of diagnosis, the median CD3(+)CD4(+) absolute blood count was 480.5 cells/µL (range, 165-632 cells/µL), whereas the plasma HIV load was undetectable in all cases. Histopathologic analysis of lesion biopsies showed a moderately dense dermal polytypic plasma cell infiltrate. Detection of HSV-2 by culture and/or polymerase chain reaction was positive for all patients, with evidence for ACV-resistant strains in 6 of 8 cases. In addition, viral resistance to ACV was found only in HSV-2 isolated from ulcerative lesions, whereas purely pseudotumoral ones harbored sensitive strains. Durable control was observed with HSV DNA polymerase inhibitors in only 2 cases, and the immunomodulators imiquimod and thalidomide allowed 5 patients to reach sustained complete response. HSV-2-related pseudolymphoma in HIV-infected patients is characterized by a predominant polyclonal lymphoplasmacytic infiltration, and is frequently refractory to antiherpetic drugs. Immunomodulatory therapeutic strategies using thalidomide showed consistent efficacy, and should be considered early during the course of disease.

Vulväre Präkanzerosen

Human papilloma virus (HPV)-induced vulvar intraepithelial neoplasia (VIN) is the most common premalignant lesion of the vulva (90% of VIN). The incidence of this disease has increased over the last decades, and is presently approximately 5–7/100,000 women/year in Germany. The median age of affected women is 46 years, and the disease is often multifocal and multicentric. Non-HPV-induced VIN is rare (10%) and is mainly found in older women. The symptoms of women presenting with VIN are often unspecific, such as itching and burning sensations or a palpable lesion, and the diagnosis is made by colposcopy and biopsy. The standard therapy is complete excision with free margins either surgically or by laser vaporization. The immunomodulator imiquimod is highly effective but not licensed for this disease but may be applied in off-label use. The second most common premalignant lesion is Paget’s disease, and a biopsy is used to verify the diagnosis suspected by colposcopy. Therapeutic intervention consists of wide excision or laser vaporization and recurrences are frequent.

Leishmania major: In vitro and in vivo anti-leishmanial activity of paromomycin ointment (Leshcutan) combined with the immunomodulator Imiquimod

Paromomycin at 25, 50 and 100 μg/ml, inhibited the growth of Leishmania major amastigotes by 34.5%, 61.2%, 74.9% and 85.4%, 89.9%, 95.7% on the 2nd and the 4th day of treatment in culture, respectively. Methylbenzethonium chloride at 0.1 and 0.5 μg/ml and Imiquimod at 5 and 10 μg/ml, administered separately, inhibited the parasite development by 39.5% and 65.2% and 31.5% and 47.7%, respectively. Imiquimod (5–10 μg/ml) combined with either paromomycin (25, 50 and 100 μg/ml) or methylbenzethonium chloride (0.1 and 0.5 μg/ml) showed an anti-leishmanial additive effect. A 10 day topical treatment, twice daily, with an ointment containing 15% paromomycin and 12% methylbenzethonium chloride (Leshcutan), either undiluted or diluted 1:5 in soft white paraffin combined with 5% Imiquimod cream (Aldara), was as effective as Leshcutan given alone. The present study suggests that a combination of Aldara and Leshcutan is as effective as Leshcutan given alone in the topical treatment of CL caused by L. major.

Design and physicochemical characterisation of a bioadhesive patch for dose-controlled topical delivery of imiquimod

Clinical use of the imidazoquinoline immunomodulator imiquimod for the topical treatment of dysplastic and neoplastic lesions has increased markedly in recent years. However, despite guidance from the manufacturer of the proprietary imiquimod cream, there seems to be little consensus between clinicians as to the topically applied dose. Given that patients often apply the cream themselves at home, further dosing variability is expected and, consequently, accurate comparison of the results of different published studies is difficult. This paper describes, for the first time, the formulation and physicochemical characterisation of a bioadhesive patch for dose-controlled topical delivery of imiquimod as well as a new HPLC method for sensitive fluorescence determination of imiquimod released from such systems. Patches containing imiquimod loadings of 4.75, 9.50 and 12.50 mg cm −2 all released significantly more drug across a model membrane than the proprietary cream over a period of 6 h. Inclusion of imiquimod in patches did not adversely affect their physicochemical properties. Of major importance, patches contained defined drug loadings per unit area; therefore, their use could reduce inter-clinician variability. This would make critical comparison of clinical studies and determination of an appropriate imiquimod dose for successful treatment much simpler. Since bioadhesive formulations are capable of adhering to body tissues in moist environments, the use of a bioadhesive patch system may allow extension of the clinical uses of imiquimod to the treatment of neoplastic conditions of the oral cavity and cervix, as well as the vulva.

Leishmaniasis--current chemotherapy and recent advances in the search for novel drugs.

Abstract The chemotherapy currently available for leishmaniasis is far from satisfactory. Resistance to the pentavalent antimonials, which have been the recommended drugs for the treatment of both visceral (VL) and cutaneous leishmaniasis (CL) for >50 years, is now widespread in India. Although new drugs have become available in recent years for the treatment of VL, including AmBisome ® , the excellent but highly expensive liposomal formulation of amphotericin B, and the oral drug miltefosine, which has now been registered in India, treatment problems remain. Parenteral and topical formulations of the aminoglycoside paromomycin offer potential treatments for VL and CL, respectively. The search for new drugs continues, with bisphosphonates, for example, risedronate and pamidronate, and plant derivatives such as licochalcone A and quinoline alkaloids being reported to have activity against experimental animal infections. The immunomodulator imiquimod has proved to be an adjunct for CL therapy. Many potential drug targets have been identified in biochemical and molecular studies, and some have been validated. Attempts to exploit these targets are in progress.

Treatment of experimental leishmaniasis with the immunomodulators imiquimod and S-28463: efficacy and mode of action.

There is a need for new, effective, and less toxic treatments for leishmaniasis, an infectious disease caused by Leishmania protozoa and is a major cause of suffering and morbidity in much of the developing world. Imiquimod, an immune-response modifier, has recently been approved by the Food and Drug Administration for the treatment of genital warts caused by human papillomaviruses. Imiquimod initiates a local immune reaction, including the stimulation of macrophages, resulting in resolution of human papillomavirus infection and regression of the viral lesion. Since imiquimod activates a number of immune cells, including macrophages, which are the only host cells of Leishmania species, an investigation was done to determine whether it induces leishmanicidal properties in infected macrophages in vitro and in vivo in a mouse model. Imiquimod and a related compound, S-28463, effectively stimulated leishmanicidal activity in macrophages; moreover, imiquimod stimulated signal transduction associated with inducing nitric oxide synthesis in macrophages.

Cytokine induction by the immunomodulators imiquimod and S-27609.

Imiquimod (R-837, S-26308) and the analogue S-27609 were evaluated for cytokine induction in human blood cells. Both compounds induced interferon-alpha (IFN), tumor necrosis factor-alpha (TNF), interleukin (IL)-1 beta, and IL-6 with S-27609 being 5 to 10 times more potent. Imiquimod and S-27609 also induced IL-1 alpha, IL-1 receptor antagonist, IL-10, granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte CSF (G-CSF), and macrophage inflammatory protein-1 alpha. The profile of cytokines induced by imiquimod and S-27609 was different from those seen with lipopolysaccharide and polyinosinic-polycytidylic acid. Kinetic studies with both imiquimod and S-27609 revealed induction of cytokines as early as 1-4 h after stimulation. Although most of the cytokines produced by S-27609 were secreted, significant concentrations of IL-1 alpha and IL-1 beta remained intracellular. Monocytes were largely responsible for the cytokines produced. Finally, S-27609-induced mRNA expression for TNF, IFN, and IL-8, and this induction did not require protein synthesis. Taken together, these studies extend previous findings by showing induction of additional cytokines and providing insight into the mechanism of cytokine induction by these molecules.

Cellular requirements for cytokine production in response to the immunomodulators imiquimod and S-27609.

Imiquimod (R-837) and its analog, S-27609, belong to a class of imidazoquinolinamines that have potent antitumor and antiviral effects in animals. Much of their biologic activity is a result of the induction of cytokines, including interferon-alpha (IFN-alpha), tumor necrosis factor alpha (TNF), and others. In this study, the cells responsible for S-27609- and imiquimod-induced cytokine production were characterized. E rosette+ T cells were not the major cell population responsible for IFN-alpha and TNF in response to S-27609 or imiquimod. In contrast, E rosette- cells and unseparated PBMC produced similar concentrations of IFN-alpha and TNF in response to S-27609 and imiquimod. Elimination of monocytes by treatment with the lysosomotropic agent L-leucine methyl ester (LME) or depletion using antibody to CD14 and immunomagnetic beads abrogated IFN-alpha and TNF production induced by S-27609, imiquimod, or LPS but not poly(I)/(C). LME treatment also abolished interleukin (IL)-1 alpha, IL-beta, IL-6, and IL-8 production stimulated by S-27609 and imiquimod. Removal of HLA-DR+ or CD36+ monocytes also caused a significant reduction in S-27609- and imiquimod-induced IFN-alpha and TNF. Elimination of B cells, NK cells, and dendritic cells did not significantly reduce cytokine induction in response to S-27609. Thus, the cell population responsible for the majority of cytokine release in human PBMC in response to S-27609 and imiquimod is a E rosette-, CD14+, CD36+, HLA-DR+ monocyte.

Cytokine induction in mice by the immunomodulator imiquimod.

Imiquimod has been identified as a potent antiviral and antitumor agent in animal models. The biological activity associated with imiquimod has been attributed to its induction of interferon (IFN)-alpha. The present studies evaluated imiquimod administered orally for its ability to stimulate production of IFN and other cytokines in mice. The cytokine profile induced by imiquimod was compared with other known immunomodulators. Imiquimod was found to stimulate increased serum IFN in mice. Daily dosing of imiquimod for five consecutive days led to diminished production of IFN in mice as measured after the final dose. Elevated levels of serum tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 but not IL-1 alpha were found in serum from mice treated with imiquimod. Imiquimod produced significantly higher levels of IFN but lower levels of TNF and IL-6 and IL-1 alpha than lipopolysaccharide. Polyinosinic acid:polycytidylic acid induced significantly higher amounts of IFN but lower levels of TNF and IL-6 than imiquimod. Imiquimod stimulated significantly higher levels of IFN when compared with 2-amino-5-bromo-6-phenyl-4(3H)-pyrimidinone (ABPP) and similar levels of IFN when compared with tilorone. Neither ABPP nor tilorone induced TNF or IL-6. Finally, imiquimod stimulated TNF, IFN, and IL-6 production in cultures of mouse spleen and bone marrow cells. These studies demonstrate that imiquimod induces not only IFN but other cytokines as well, all of which may contribute to its biological activity.