Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Imiquimod (IMQ), an activator of Toll-like receptor-7 (TLR-7), induces by several routes a profound anti-viral and anti-tumor effect in vivo. Physiologically, the immune system is using perforin-containing granules of cytotoxic T lymphocytes (CTL) towards the same biological purpose. This functional synergism prompted our current experiments addressing the question whether IMQ may influence perforin-release and/or induce perforin in CTLs in vitro. In peripheral lymphocytes of healthy and diseased subjects, IMQ induced a significant increase of perforin(+) CTLs within 12h in all experiments performed. This effect was most pronounced in CTLs of patients suffering from atopic dermatitis, a model disorder for subnormal perforin expression: as compared to perforin(+) CTLs detected at time point zero (100%), up to 270% of perforin(+) CTLs were induced by 2.5 microg/ml [corrected] IMQ. Perforin release from peripheral blood CTLs after PMA/ionomycin-stimulation was not influenced significantly by IMQ. Thus, the biological activity of IMQ appears to exceed its previously known functions, inasmuch as it boosts up significantly the perforin-granule system.
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PMID:Imiquimod, a Toll-like receptor-7 agonist, induces perforin in cytotoxic T lymphocytes in vitro. 1507 49

Bypassing molecular mechanisms of apoptosis deficiency may be of great utility for the successful treatment of malignant tumors. We have discovered that imiquimod, a small-molecule immunomodulator, exerts rather tumor-selective direct pro-apoptotic activity in vivo and in vitro towards cutaneous metastases of malignant melanoma, an aggressive skin tumor. This pro-apoptotic activity was not detectable with resiquimod, a closely related structural analogue whose pro-inflammatory activity is even greater than that of imiquimod. Unresponsiveness of some melanoma metastases to imiquimod in vivo corresponded to resistance towards imiquimod-induced apoptosis in vivo and in vitro. At the molecular level, the pro-apoptotic activity of imiquimod was independent of membrane-bound death receptors, but depended on Bcl-2 expression as demonstrated by overexpression of Bcl-2 in melanoma cells. Imiquimod is the first topical compound with the potential to bypass molecular mechanisms of apoptosis deficiency, a concept that may be relevant for other tumors as well.
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PMID:Death receptor-independent apoptosis in malignant melanoma induced by the small-molecule immune response modifier imiquimod. 1514 Feb 51

Imiquimod, the first member of the imidazoquinoline family of immune response modifiers, has proven good clinical efficacy against basal cell carcinomas and actinic keratoses in several independent studies. In addition, there is recent evidence that imiquimod is also efficacious against other tumors such as cutaneous metastases of malignant melanoma or vascular tumors. Imiquimod exerts its antitumoral effect, at least in part, through binding to TLR-7 and TLR-8 on dendritic cells followed by secretion of a multitude of proinflammatory cytokines. The net result of this proinflammatory activity is a profound tumor-directed cellular immune response. However, recent experimental and clinical data indicate that imiquimod also possesses considerable direct pro-apoptotic activity against tumor cells both in vitro and in vivo. This novel mode of action appears to be independent of membrane bound death receptors, but involves caspase activation. Induction of apoptosis by imiquimod is, at least in part, presumably mediated through Bcl-2-dependent release of mitochondrial cytochrome c and subsequent activation of caspase-9. The structural analogue, resiquimod, exhibited very limited, if any, such pro-apoptotic activity, possibly due to its lacking ability to enter the cell. Bypassing molecular mechanisms of apoptosis deficiency by a topical compound may be of great utility for treating certain cutaneous tumors.
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PMID:Immune modulation and apoptosis induction: two sides of the antitumoral activity of imiquimod. 1525 60

Imiquimod, available as a 5% cream, is a new topical treatment for adults with superficial basal cell carcinoma (BCC). The exact mechanism of action of imiquimod in superficial BCC is unknown. Imiquimod may act as a toll-like receptor-7 agonist, and is thought to exert its anti-tumor effect via modification of the immune response and stimulation of apoptosis in BCC cells. Topical imiquimod 5% cream effectively increased clinical and histologic clearance of single superficial BCC lesions compared with vehicle in patients enrolled in two large, well designed trials. Patients applied imiquimod five or seven times per week or vehicle for 6 weeks, and the composite clearance rates at 12 weeks post-treatment for the corresponding treatment groups were 75%, 73%, and 2%, respectively. In a trial investigating the long-term efficacy of imiquimod 5% cream following application five times per week for 6 weeks, a clinical clearance rate of 90% was reported at the initial 12-week post-treatment examination. The estimated rate of clinical clearance at the 1-year follow-up visit was 84%. Application site and local skin reactions were the most common adverse events reported by imiquimod recipients. The severity of erythema, erosion, and scabbing/crusting correlated positively with the composite and histologic response rates.
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PMID:Imiquimod: in superficial basal cell carcinoma. 1594 96

We present a case of Bowen disease affecting the eyelid that was successfully treated with imiquimod. The clinical presentation, histopathology, and treatment of this case are presented. The tumor was treated with imiquimod for 3 months, leading to complete resolution of the disease both clinically and histopathologically. There was no evidence of recurrence 5 months after treatment cessation. Imiquimod was safely used on the eyelid in this case and may avoid extensive periocular tumor excision and reconstruction in Bowen disease.
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PMID:Bowen disease of the eyelid successfully treated with imiquimod. 1605 54

The aim of the present study was to assess the local application of imiquimod cream 5% as an alternative mode of therapy for high-grade vaginal intraepithelial neoplasia (VAIN 2/3). Positive human papillomavirus (HPV) patients with multifocal high-grade VAIN (2/3) not involving the vaginal vault in hysterectomized patients took part in this study. The treatment consisted of vaginal application of the cream under colposcopic guidance. Following management, biopsies were obtained from the previously recorded lesions. p53 expression was recorded prior and after therapy. Seven patients with VAIN 2/3 took part in this study. Six patients (86%) were positive for high-risk HPV type while three (43%) women who were positive for p53 nuclei prior to therapy were found to be negative following treatment. After treatment, 86% of the patients were found to have either HPV infection or low-grade VAIN. During follow-up, two patients (28.5%) were managed by vaginectomy, one for persistent and one for recurrent high-grade VAIN. Currently, from the five patients that are followed, three have simple HPV infection and two, VAIN 1. Imiquimod cream 5% might represent an alternative although not permanent method of management in young, HPV-positive women with multifocal high-grade lesions of the vagina (VAIN 2/3).
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PMID:Can local application of imiquimod cream be an alternative mode of therapy for patients with high-grade intraepithelial lesions of the vagina? 1617 42

The incidence of cutaneous squamous cell carcinomas (SCC) has been increasing by about 5% per year of the past 40 years in a population which is growing continuously older and as such presents a growing therapeutic challenge. We report on two elderly female residents of a retirement home with histologically confirmed SCC on the back of the hand. In one case the tumor was completely excised and covered with a graft. In the second case the patient refused all surgical and radiotherapeutic procedures. We sought an adequate therapeutic alternative considering the extent and thickness of the tumor. Topical application of the immune response modifier imiquimod appeared to represent an alternative solution because of its unique antineoplastic mode of action, even though there was no published experience with this approach. She has remained tumor-free for four years, justifying our decision. In both cases, a comparable cosmetic result with full functional capacity of the hands was obtained. Imiquimod 5% cream was approved last year for the treatment of superficial basal cell carcinoma.
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PMID:Therapy of cutaneous squamous cell carcinoma in two retirement home residents. 1618 65

The efficacy and safety of imiquimod, an immune-response modifier approved for the treatment of anogenital warts that has antiviral and antitumor activity, in the management of an extensive superficial basal cell carcinoma (sBCC) of the face as an alternative to surgical treatment was evaluated in a 75-year-old male with a 4-year history of a progressively enlarging lesion located on the right temporal region. Imiquimod 5% cream was applied daily until clinical resolution. Histopathological confirmation of clinical diagnosis and of tumor clearance were performed before starting treatment and at the end of treatment, respectively. Moreover, monthly post-treatment follow-up visits were planned. At physical examination, an ovalar, erythematous and slightly infiltrated plaque of 5 x 4 cm in size (approximately 20 cm2), partly eroded and crusted, with a sharp, raised, pearly edge, was evident on the right temporal region of the patient. Histopathological examination of a biopsy specimen showed the typical features of sBCC. Imiquimod 5% cream applied daily for 5 months produced complete clinical and histological clearance. No adverse events but considerable irritation were reported during treatment and no relapses were clinically observed at the 6-month follow-up visit. Our findings confirm current reports from the literature showing imiquimod 5% cream to be an effective treatment for sBCC that is especially valuable in avoiding disfigurement in cases of single large lesions located on the face or in those patients who may not be surgical candidates.
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PMID:Treatment of an extensive superficial basal cell carcinoma of the face with imiquimod 5% cream. 1637 77

It has been estimated that approximately 4 million Germans are suffering from actinic keratoses, which are considered as a carcinoma in situ today. Typically, actinic keratoses appear in sun-exposed skin areas, conventionally they have been treated by curettage and cryotherapy. In the last years, new therapeutic modalities with a high efficacy and patient contentment are available. Among these, the photodynamic therapy (PDT), the anti-tumor treatment with 3 % Diclofenac in 2.5 % hyaluronic acid as well as the introduction of Imiquimod as an immune response modifier are the most important. The rate of complete clearance from actinic keratoses varies between 50 and 90 % in clinical trials. In contrast to the conventional treatment modalities, these new options promise advantages in the treatment of field and offer excellent cosmetic outcomes, too. This overview will report on the actual treatment opportunities and a careful consideration in the year 2006.
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PMID:[Modern treatment modalities in actinic keratoses of the skin]. 1649 70

Imiquimod, a small-molecule immune response modifier of the imidazoquinoline family, has shown profound antitumoral and antiviral efficacy both in vitro and in clinical applications in vivo. It has been demonstrated that this activity is mediated through the Toll-like receptor (TLR)7- and TLR8-signaling cascade resulting in the secretion of proinflammatory cytokines and, consecutively, induction of a tumor-directed cellular immune response. In addition, imiquimod exerts a direct proapoptotic activity in tumor cells. We demonstrate here that imiquimod induces activation of the transcription factor NF-kappaB and the downstream production of proinflammatory cytokines in the absence of TLR7 and TLR8. In Chinese hamster ovary cells stably transfected with the human adenosine receptor subtypes, we then show in radioligand-binding competition experiments that imiquimod binds to adenosine receptors at concentrations relevant in clinical settings, with highest affinities to the A(1) and A(2A) subtypes. The effect on the receptor-mediated activation of adenylyl cyclase was also studied, and these experiments revealed that imiquimod acts as an adenosine receptor antagonist. In addition, imiquimod had an inhibitory effect on adenylyl cyclase activity downstream from the receptor. Finally, using transformed human keratinocytes, we provide experimental evidence that imiquimod and A(2A) adenosine receptor-specific compounds similarly induce proinflammatory cytokines in the absence of immune cells. Thus, imiquimod appears to suppress an important feedback mechanism of inflammation by antagonism of adenosine receptor-dependent increase of cAMP and a concomitant receptor-independent inhibition of cAMP production. These novel mechanisms presumably act synergistic with the positive induction of proinflammatory cytokines and can, at least in part, explain the profound inflammation observed in some patients in vivo.
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PMID:The small antitumoral immune response modifier imiquimod interacts with adenosine receptor signaling in a TLR7- and TLR8-independent fashion. 1657 88


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