Mechanism of paclitaxel activity in Kaposi's sarcoma

Weekly paclitaxel treatment in the first-line therapy of classic Kaposi sarcoma: A real-life study

Kaposi sarcoma is an angioproliferative disease associated with human herpes virus 8 infection. Classic Kaposi sarcoma (CKS) usually develops in older age. Although CKS often does not require systemic therapy, systemic therapy can be administered in progressively symptomatic patients. In this real-life study, we purposed to determine effectiveness and safety of weekly paclitaxel therapy in the first-line treatment of CKS. In this cross-sectional retrospective study, we analyzed the clinical data of 44 patients with CKS who received first-line paclitaxel therapy between January 2000 and December 2020. Paclitaxel was administered by intravenous infusion 80 to 100 mg/weekly. The median age of the patients was 67 years (range, 39-86 years), and majority male (77.2%). All patients had cutaneous involvement in extremities. The median follow-up time from paclitaxel treatment was 39.1 (range, 3.7-173.5) months. The median progression free survival from start of therapy was 35.1 months (range, 2-144 months). Complete response, partial response and stable disease were observed in 7 (15.9%), 28 (63.7%) and 6 (13.6) patients, respectively. Objective control rate was 79.6%, and the median response time after the last dose of paclitaxel was 18.2 months. A total of 4 patients (9.1%) had grade 3 to 4 neutropenia, but it was not complicated by febrile neutropenia. Three patients (6.8%) experienced grade 3 to 4 peripheral neuropathy. No patient had grade 3 to 4 allergic reaction. There was no drug-related death. According to our results, paclitaxel is an effective therapy option with an acceptable safety profile for patients with advanced CKS.

Insights into the biotechnology potential of Methanosarcina

Methanogens are anaerobic archaea which conserve energy by producing methane. Found in nearly every anaerobic environment on earth, methanogens serve important roles in ecology as key organisms of the global carbon cycle, and in industry as a source of renewable biofuels. Environmentally, methanogenic archaea play an essential role in the reintroducing unavailable carbon to the carbon cycle by anaerobically converting low-energy, terminal metabolic degradation products such as one and two-carbon molecules into methane which then returns to the aerobic portion of the carbon cycle. In industry, methanogens are commonly used as an inexpensive source of renewable biofuels as well as serving as a vital component in the treatment of wastewater though this is only the tip of the iceberg with respect to their metabolic potential. In this review we will discuss how the efficient central metabolism of methanoarchaea could be harnessed for future biotechnology applications.

Amelioration of Combination of Paclitaxel and Di Allyl Sulfide on the Alterations of Bcl2, P53 and Apoptosis Changes Against 7,12 Di Methyl Benz (A) Anthracene Induced Skin Cancer in Experimental Animals

The purpose of this study was to investigate the Bcl2, P⁵³ and apoptosis changes against skin cancer in experimental animals. Skin cancer is the most common form of human cancer. It is estimated that over 1 million new cases occur annually. The annual rates of all forms of skin cancer are increasing each year, representing a growing public concern. It has also been estimated that nearly half of all Americans who live to age 65 are likely to develop skin cancer at least once. Skin cancer was induced in rats by Di Methyl Benz (a) Anthracene at the dosage of DMBA (5 µg) per animal, three times a week for 28 weeks after conformation of skin cancer treated with Paclitaxel and Di allyl sulfide for 30 days. The levels of Bcl2 gene expression were significantly decreased and P⁵³gene expression were markedly increased in Paclitaxel and Di allyl sulfide treated animals when compared with cancer bearing animals. The treatment with combination of Paclitaxel and Di allyl sulfide effectively reduced Bcl2 protein expression and also increased P⁵³gene expression. Moreover, the levels of Bcl2 and P⁵³ a good indicators of restoring the skin architecture, were also reversed in skin damage subjects after treatment with the herbal compounds preparation. So, from the obtained results it is concluded that a combination of Paclitaxel and Di allyl sulfide is capable of restoring the skin architecture and can also increase the apoptosis activities in skin cancer rats.

[Successful treatment with paclitaxel of a visceral relapse of post-transplant Kaposi's sarcoma]

We report the observation of a patient who presented with post-transplant Kaposi's sarcoma after a delay of eight months with a dual cutaneous and palatal localisation. The reduction in immunosuppressive treatment and the introduction of Rapamune® allowed good clinical progress initially with regression of the skin lesions. He subsequently presented later a skin relapse with visceral localisation. Chemotherapy was conducted based on weekly paclitaxel infusions allowing partial remission and maintenance of renal graft function with good clinical tolerance.

Selectivity Enhancement of Paclitaxel Liposome Towards Folate Receptor-Positive Tumor Cells by Ligand Number Optimization Approach

The present work aims to develop folate-targeted paclitaxel liposome (F-PTX-LIP), which will selectively target tumor cells overexpressing folate receptor (FR) and leave normal cells. Liposomes were prepared by thin-film hydration method followed by post-insertion of synthesized ligand 1,2-distearoyl-sn-glycero-phosphoethanolamine-polyethyleneglycol 2000-folic acid (DSPE-PEG2000-FA) on the outer surface of the liposome. The synthesized ligand was evaluated for in vivo acute toxicity in Balb/c mice. Developed liposomal formulations were characterized using transmission electron microscopy (TEM) and small-angle neutron scattering (SANS). We have investigated the effect of ligand number on cell uptake and cytotoxicity by confocal laser scanning microscopy (CLSM), competitive inhibition and 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assay. Compared to lung adenocarcinoma cells (A549), uptake in human ovarian carcinoma cells (SKOV3) was 2.2- and 1.2-fold higher for liposome with 480 and 240 ligand number respectively. Competitive inhibition experiment shows that prior incubation of SKOV3 cells with free folic acid significantly reduced the cell uptake of F-PTX-LIP with 480 ligand number (480 F-PTX-LIP) by 2.6-fold. 480 F-PTX-LIP displays higher cytotoxicity than free drug and PTX liposome. Moreover, it specifically targets the cells with higher folate receptor expression. Optimized 480 F-PTX-LIP formulation can be potentially useful for the treatment of folate receptor-positive tumors.

Effects of paclitaxel and resveratrol on blood characteristics in rabbits

We investigated the adverse effects of paclitaxel (PAC) on blood characteristics including the percentage of alpha naphthyl acetate esterase (ANAE)-positive peripheral blood lymphocytes, white cell count, number of neutrophil nuclear lobe and, erythrocyte diameter, and the protective effects of resveratrol (RES) on these characteristics. Male New Zealand rabbits were assigned to four groups. The control group (C) was given 40 ml normal saline, the PAC group was given 5 mg/kg PAC in 40 ml normal saline, the RES group was given 4 mg/kg RES in 40 ml normal saline, and the PAC + RES group was given 5 mg/kg PAC + 4 mg/kg RES in 40 ml normal saline. All injections were performed intravenously once/week for 8 weeks. PAC caused an increased total percentage of lymphocytes and monocytes, which was associated with neutropenia. The PAC group showed a right shift in the lobulation curve of neutrophil nuclei together with a decreased percentage of ANAE-positive lymphocytes. RES reduced the percentage of ANAE-positive lymphocytes, slightly increased the percentage of neutrophil leukocytes and reduced the total lymphocyte count. Administration of RES combined with PAC prevented, while PAC induced, neutropenia and lymphocytosis, and increased the percentage of ANAE-positive lymphocytes.

Tonsillar Kaposi Sarcoma in an HIV-Negative Patient: A Case Report

Kaposi's sarcoma (KS) is a rare malignancy associated with AIDS and usually affects skin. The most common causative agent is the Human Herpes Virus Type 8 (HHV-8). In the literature, there are few case reports about KS with no association to AIDS. In this case report, we report a 72-year-old HIV (-) woman who presented to our clinic with a complaint of fast swelling in the right palatine tonsil and was histopathologically diagnosed as tonsillar KS.

The Expression of CD154 by Kaposi's Sarcoma Cells Mediates the Anti-Apoptotic and Migratory Effects of HIV-1-Tat Protein

Kaposi's sarcoma (KS) is a malignancy associated to conditions of immune system impairment such as HIV-1 infection and post-transplantation therapy. Here we report that HIV-1-Tat protein, at concentrations well below those detected in AIDS patients, up-regulates the expression of both CD40 and CD154 on KS cells. This occurred also in the presence of vincristine, that at doses shown to induce apoptosis decreased the expression of both CD40 and CD154 on KS cells. The treatment with a soluble CD40-muIg fusion protein (CD40 fp) that prevents the binding of CD154 with cell surface CD40, as well as the transfection with a vector for soluble CD40 (KS sCD40), decreased the anti-apoptotic effect of Tat. Moreover, Tat-induced motility of KS cells was inhibited by soluble CD40 fp. Tat also enhanced the expression of intracellular proteins known to transduce signals triggered by CD40 engagement, in particular TRAF-3. Tat as well as soluble CD154 (sCD154) prevented vincristine-induced reduction of TRAF-3 in KS cells transfected with a vector for neomycin resistance (KS psv-neo), but not in KS sCD40. Immunoprecipitation studies showed that Tat induced CD40 / TRAF-3 association and that this binding was abrogated upon the incubation with the soluble CD40 fp. These data suggest that Tat activates the CD40-CD154 pathway by enhancing the membrane expression of CD40 and in particular of CD154, and by activating the TRAF-3-dependent signaling pathway of CD40. These findings indicate that the CD40-CD154 pathway mediates the anti-apoptotic and migratory effects of HIV-1-Tat, suggesting the potential therapeutic benefits of blocking CD40 activation in HIV-1-associated KS.

Nanomedicine-based combination anticancer therapy between nucleic acids and small-molecular drugs

Anticancer therapy has always been a vital challenge for the development of nanomedicine. Repeated single therapeutic agent may lead to undesirable and severe side effects, unbearable toxicity and multidrug resistance due to complex nature of tumor. Nanomedicine-based combination anticancer therapy can synergistically improve antitumor outcomes through multiple-target therapy, decreasing the dose of each therapeutic agent and reducing side effects. There are versatile combinational anticancer strategies such as chemotherapeutic combination, nucleic acid-based co-delivery, intrinsic sensitive and extrinsic stimulus combinational patterns. Based on these combination strategies, various nanocarriers and drug delivery systems were engineered to carry out the efficient co-delivery of combined therapeutic agents for combination anticancer therapy. This review focused on illustrating nanomedicine-based combination anticancer therapy between nucleic acids and small-molecular drugs for synergistically improving anticancer efficacy.

Paclitaxel for AIDS-associated Kaposi’s sarcoma

Treatment options are limited for patients with advanced acquired immunodeficiency syndrome-related Kaposi's sarcoma (AIDS-KS). The management of early stage cutaneous AIDS-KS has been revolutionized by the introduction of highly active antiretroviral therapy and for most patients highly active antiretroviral therapy alone will control early stage AIDS-KS. However, patients with advanced stage Kaposi's sarcoma with visceral disease, tumor-associated edema or extensive oral disease require systemic chemotherapy in addition to antiretrovirals. The standard first-line therapy for these affected individuals is a liposomal anthracycline, and response rates of around 70% are usually achieved. For patients with refractory or recurrent AIDS-KS, treatment algorithms are less well defined. The use of paclitaxel in these circumstances is reviewed.

Pemphigus vulgaris-associated Kaposi's sarcoma: response to paclitaxel and review of the literature

Systemic corticosteroids have long been the mainstay of treatment for pemphigus patients. However, the necessity of their high-dose and long-term administration has brought about a number of complications, sometimes causing significant morbidities. Maintaining a balance between therapeutic and undesirable effects of medications is not always easily achievable. Therefore, additional treatment modalities are frequently needed to control side-effects. Kaposi's sarcoma (KS) is a rare, potentially life-threatening complication in this setting. Due to the rarity of data on pemphigus-associated KS treatment, the best therapeutic approach is still undecided. Here, we report two cases of pemphigus patients who had developed extensive KS as a result of severe immunosuppressive therapy and were successfully treated with paclitaxel. In addition, we performed a review of literature to assess the results of the previously employed treatment modalities in this setting.

Production of taxadiene from cultured ginseng roots transformed with taxadiene synthase gene

Paclitaxel is produced by various species of yew trees and has been extensively used to treat tumors. In our research, a taxadiene synthase (TS) gene from Taxus brevifolia was used to transform the roots of cultured ginseng (Panax ginseng C.A. Meyer) to produce taxadiene, the unique skeletal precursor to taxol. The TS gene was successfully introduced into the ginseng genome, and the de novo formation of taxadiene was identified by mass spectroscopy profiling. Without any change in phenotypes or growth difference in a TS-transgenic ginseng line, the transgenic TSS3-2 line accumulated 9.1 μg taxadiene per gram of dry weight. In response to the treatment of methyl jasmonate for 3 or 6 days, the accumulation was 14.6 and 15.9 μg per g of dry weight, respectively. This is the first report of the production of taxadiene by engineering ginseng roots with a taxadiene synthase gene.

Successful treatment by adding duloxetine to pregabalin for peripheral neuropathy induced by paclitaxel

Although paclitaxel is a commonly used anticancer drug, peripheral neuropathy may develop as a side effect. Worsening of the symptoms with time may cause patients who receive paclitaxel to give up their chemotherapy. Duloxetine, a serotonin- and norepinephrine-reuptake inhibitor, has been used to treat peripheral neuropathic pain. We report the case of a 68-year-old man with gastric cancer, who underwent gastrectomy and then received 8 cycles of chemotherapy involving weekly administrations of paclitaxel. Under this paclitaxel treatment, he complained of severe peripheral neuropathy, leading to a diminished quality of life. Following treatment with a combination of duloxetine and pregabalin, a remission of his symptoms was achieved. Duloxetine plus pregabalin therapy may be useful for the peripheral neuropathy induced by paclitaxel.

Paclitaxel-conjugated PEG and arginine-grafted bioreducible poly (disulfide amine) micelles for co-delivery of drug and gene

We developed a paclitaxel-conjugated polymeric micelle, ABP-PEG3.5k-Paclitaxel (APP) consisting of poly (ethylene glycol) (PEG) and arginine-grafted poly (cystaminebisacrylamide-diaminohexane) (ABP) for the co-delivery of gene and drug. The APP polymer self-assembled into cationic polymeric micelles with a critical micelle concentration (CMC) value of approximately 0.062 mg/mL, which was determined from measurements of the UV absorption of pyrene. The micelles have an average size of about 3 nm and a zeta potential of about +14 mV. Due to the positive surface charge, APP micelles formed polyplexes with plasmid DNA approximately 200 nm in diameter. The luciferase gene and mouse interleukin-12 (IL-12) gene was used to monitor gene delivery potency. APP polyplexes showed increased gene delivery efficiency and cellular uptake with higher anticancer potency than paclitaxel alone. These results demonstrate that an APP micelle-based delivery system is well suitable for the co-delivery of gene and drug.

Treatment of Disseminated Classic Type of Kaposi's Sarcoma with Paclitaxel

Classic Kaposi sarcoma (KS) is a rare human herpes virus 8-associated angioproliferative disease, and the disseminated classic type of KS in Korea is even rarer. The treatment options for classic KS vary and range from surgical excision to ionizing irradiation or chemotherapy. Recently, there have been a few reports of treating classic KS with paclitaxel, which has been used to treat AIDS-associated KS and post-transplant KS. We herein report a case of disseminated classic type KS in a 78-year-old Korean male patient who showed dramatic response after only two cycles of paclitaxel treatment.

Fibroblast Growth Factor-2 and the HIV-1 Tat Protein Synergize in Promoting Bcl-2 Expression and Preventing Endothelial Cell Apoptosis: Implications for the Pathogenesis of AIDS-Associated Kaposi's Sarcoma

Kaposi's sarcoma (KS) is a vascular tumor frequently occurring in Human Immunodeficiency Virus- (HIV-) 1-infected individuals. Our previous work indicated that the angiogenic fibroblast growth factor (FGF)-2 and the Tat protein of HIV-1, both expressed in KS lesions of HIV-infected patients, synergize at inducing angioproliferative, KS-like lesions in mice. Here we show that the development of angioproliferative lesions promoted in mice by combined Tat and FGF-2 associates with an increase in the levels of expression of the antiapoptotic Bcl-2 protein. Upregulation of Bcl-2 expression by combined FGF-2 and Tat occurs also in vitro, and this protects human primary endothelial cells from programmed cell death. As Bcl-2 is expressed in human KS lesions in a fashion paralleling the progression of the disease, these findings suggest a molecular mechanism by which Tat and FGF-2 cooperate in KS maintenance and progression in HIV-infected individuals.

A rare case of iatrogenic gingival Kaposi's sarcoma

Kaposi's sarcoma is an angioproliferative tumour rarely found in the oral cavity. We present the 3rd case of iatrogenic gingival Kaposi's sarcoma reported in the English-language literature which developed in a young patient 5 years after a renal transplant and discuss their histological features and differential diagnosis.

Human herpes virus type 8-associated Kaposi sarcoma in a pediatric liver transplant recipient

  Development of KS in pediatric liver transplant recipients is a rare entity and has dismal prognosis. Latent HHV-8 infection, immunosuppression, and genetic predisposition are possible etiological factors. Decreasing the dose or cessation of immunosuppressive drugs, switching to sirolimus with antiproliferative and antitumor properties, and different chemotherapeutic regimens are the current therapeutic strategies. We herein report a pediatric liver transplant recipient who developed generalized KS at post-transplant fifth month. The disease had an aggressive course despite the highly toxic chemotherapy. On the other hand, a prompt and durable response was provided by paclitaxel with tolerable side effects. The patient is now free of disease for at least 24 months and healthy with good graft function under sirolimus therapy as maintenance immunosuppression. Instead of highly toxic chemotherapy, paclitaxel can be used as therapeutic option in cases with generalized disease and in those who are unresponsive to conventional chemotherapy. However, new studies are needed to assess the efficacy of the paclitaxel therapy in KS in the liver transplant recipients.

4-oxo-N-(4-hydroxyphenyl)retinamide: two independent ways to kill cancer cells

Background

The retinoid 4-oxo-N-(4-hydroxyphenyl)retinamide (4-oxo-4-HPR) is a polar metabolite of fenretinide (4-HPR) very effective in killing cancer cells of different histotypes, able to inhibit 4-HPR-resistant cell growth and to act synergistically in combination with the parent drug. Unlike 4-HPR and other retinoids, 4-oxo-4-HPR inhibits tubulin polymerization, leading to multipolar spindle formation and mitotic arrest. Here we investigated whether 4-oxo-4-HPR, like 4-HPR, triggered cell death also via reactive oxygen species (ROS) generation and whether its antimicrotubule activity was related to a ROS-dependent mechanism in ovarian (A2780), breast (T47D), cervical (HeLa) and neuroblastoma (SK-N-BE) cancer cell lines.

Methodology/Principal Findings

We provided evidence that 4-oxo-4-HPR, besides acting as an antimicrotubule agent, induced apoptosis through a signaling cascade starting from ROS generation and involving endoplasmic reticulum (ER) stress response, Jun N-terminal Kinase (JNK) activation, and upregulation of the proapoptotic PLAcental Bone morphogenetic protein (PLAB). Through time-course analysis and inhibition of the ROS-related signaling pathway (upstream by vitamin C and downstream by PLAB silencing), we demonstrated that the antimitotic activity of 4-oxo-4-HPR was independent from the oxidative stress induced by the retinoid. In fact, ROS generation occurred earlier than mitotic arrest (within 30 minutes and 2 hours, respectively) and abrogation of the ROS-related signaling pathway did not prevent the 4-oxo-4-HPR-induced mitotic arrest.

Conclusions/Significance

These data indicate that 4-oxo-4-HPR anticancer activity is due to at least two independent mechanisms and provide an explanation of the ability of 4-oxo-4-HPR to be more potent than the parent drug and to be effective also in 4-HPR-resistant cell lines. In addition, the double mechanism of action could allow 4-oxo-4-HPR to efficiently target tumour and to eventually counteract the development of drug resistance.

Squalene: A natural triterpene for use in disease management and therapy

Squalene is a natural lipid belonging to the terpenoid family and a precursor of cholesterol biosynthesis. It is synthesized in humans and also in a wide array of organisms and substances, from sharks to olives and even bran, among others. Because of its significant dietary benefits, biocompatibility, inertness, and other advantageous properties, squalene is extensively used as an excipient in pharmaceutical formulations for disease management and therapy. In addition, squalene acts as a protective agent and has been shown to decrease chemotherapy-induced side-effects. Moreover, squalene alone exhibits chemopreventive activity. Although it is a weak inhibitor of tumor cell proliferation, it contributes either directly or indirectly to the treatment of cancer due to its potentiation effect. In addition, squalene enhances the immune response to various associated antigens, and it is therefore being investigated for vaccine delivery applications. Since this triterpene is well absorbed orally, it has been used to improve the oral delivery of therapeutic molecules. All of these qualities have rendered squalene a potentially interesting excipient for pharmaceutical applications, especially for the delivery of vaccines, drugs, genes, and other biological substances. This paper is the first review of its kind and offers greater insight into squalene's direct or indirect contribution to disease management and therapy.

Inhibition of expression of anti-apoptotic protein Bcl-2 and induction of cell death in radioresistant human prostate adenocarcinoma cell line (PC-3) by methyl jasmonate

Hormone refractory human prostate cancer cell lines are known to be radioresistant, a feature attributed to their ability to induce anti-apoptotic proteins of the Bcl-2 family when exposed to radiation. We investigated whether pro-apoptotic compounds such as methyl jasmonate, a plant stress hormone, can counteract the radiation-induced anti-apoptotic mechanism in a human prostate cancer cell line PC-3. Significant (p<0.05) increase in cytotoxicity was observed in the combined treatment groups compared to single treatments with methyl jasmonate or gamma-radiation. Treatment of irradiated PC-3 cells with methyl jasmonate resulted in suppression of anti-apoptotic Bcl-2 protein and elevation of caspase-3 activity. Our results showed increased apoptosis in the combined treatment group as compared to the irradiated group or the untreated control. In summary, methyl jasmonate suppressed the radiation-induced Bcl-2 expression and enhanced the radiation sensitivity of human prostate cancer cells.

Weekly paclitaxel for advanced aggressive classic Kaposi sarcoma: experience in 17 cases

BACKGROUND

Paclitaxel has proved to be highly effective in the treatment of severe AIDS-related Kaposi sarcoma (KS), for which it is now considered as a second-line monotherapy. Taxanes were recently shown to be active also in classic, endemic and post-transplantation KS.

OBJECTIVES

To evaluate the clinical efficacy and tolerability of standardized paclitaxel treatment (100 mg weekly, intravenously) in a homogeneous group of 17 patients with advanced aggressive and refractory classic KS (cKS).

METHODS

Seventeen patients with aggressive refractory cKS (stage IIIBc-IVBcv) were treated with intravenous paclitaxel 100 mg weekly. The response to the therapy was evaluated after 12 weeks. A maintenance treatment every 2 weeks was introduced for most of the patients and a final evaluation was made.

RESULTS

A partial/complete response was achieved in 14 of 17 patients. Two patients had allergic reactions, for which treatment was discontinued. One patient had progression of disease despite initial improvement. Patients received a mean of 16.8 courses. The treatment was generally well tolerated. Mean time to recurrence was 4.5 months from the end of the therapy and 7.35 months from the 12th course. In four of 10 patients who relapsed at follow-up, the recurrence was mild and responsive to local treatment, while the other six relapsing patients repeated paclitaxel with good response in five of them.

CONCLUSIONS

This study shows that low-dose paclitaxel proved to be effective and well tolerated in patients with aggressive refractory cKS, controlling the aggressiveness of the disease. The treatment can be repeated with good response.

HDAC6 deacetylation of tubulin modulates dynamics of cellular adhesions

Genetic or pharmacological alteration of the activity of the histone deacetylase 6 (HDAC6) induces a parallel alteration in cell migration. Using tubacin to block deacetylation of alpha-tubulin, and not other HDAC6 substrates, yielded a motility reduction equivalent to agents that block all NAD-independent HDACs. Accordingly, we investigated how the failure to deacetylate tubulin contributes to decreased motility in HDAC6-inhibited cells. Testing the hypothesis that motility is reduced because cellular adhesion is altered, we found that inhibiting HDAC6 activity towards tubulin rapidly increased total adhesion area. Next, we investigated the mechanism of the adhesion area increase. Formation of adhesions proceeded normally and cell spreading was more rapid in the absence of active HDAC6; however, photobleaching assays and adhesion breakdown showed that adhesion turnover was slower. To test the role of hyperacetylated tubulin in altering adhesion turnover, we measured microtubule dynamics in HDAC6-inhibited cells because dynamic microtubules are required to target adhesions for turnover. HDAC6 inhibition yielded a decrease in microtubule dynamics that was sufficient to decrease focal adhesion turnover. Thus, our results suggest a scenario in which the decreased dynamics of hyperacetylated microtubules in HDAC6-inhibited cells compromises their capacity to mediate the focal adhesion dynamics required for rapid cell migration.

Systemic treatment of AIDS-related Kaposi sarcoma: current status and perspectives

Kaposi's sarcoma (KS) is the most frequent type of cancer in patients with Acquired Immune Deficiency Syndrome (AIDS). In the western world, its incidence decreased dramatically in the era of highly active anti-retroviral therapy (HAART). In contrast, the incidence of KS has been steadily climbing in parallel with the AIDS epidemic in Africa over the past 10-15 years, being the most common cancer in adult men in countries like Uganda and Zimbabwe. AIDS-KS can be diagnosed at any stage of HIV infection, although it more commonly occurs in the setting of severe immune suppression, especially with an elevated viral load. Up to now, AIDS-KS is still an incurable disease. Its clinical course is variable, ranging from very indolent cases, requiring no or minimal therapy, to a rapidly progressive disease. Various local therapies are available to control small and asymptomatic lesions, while cytotoxic, immunological and biological therapies can be considered for more aggressive disease. The primary goal of therapy in most of the cases is to provide safe and effective palliation, in order to quality of life. Optimal anti-retroviral therapy is a key component of AIDS-KS management. There are still many questions to be answered in the management of patients with AIDS-KS, such as (1) What are the therapeutic agents that should be used in this disease, and in which sequence? and (2) What are the benefits and risks expected with each treatment option? The aim of this review is to discuss the systemic management of AIDS-KS, with special focus on the above mentioned questions.

Treatment with taxanes of refractory or life-threatening Kaposi sarcoma not associated with human immunodeficiency virus infection

BACKGROUND

Kaposi sarcoma (KS) is an angioproliferative disease that may represent a difficult therapeutic challenge in disseminated stages. The efficacy of taxanes (paclitaxel and docetaxel), as agents with antiangiogenic properties, has been described previously in the treatment of patients with acquired immunodeficiency syndrome (AIDS)-associated KS but remains unknown in the treatment of patients with refractory or life-threatening KS without human immunodeficiency (HIV) infection.

METHODS

During the past 6 years, 12 non-HIV-infected patients with refractory KS were treated with paclitaxel (175 mg/m2 every 3 wks) or docetaxel (60 mg/m2 every 3 wks).

RESULTS

All patients improved dramatically after chemotherapy. Partial desinfiltration (n = 6) or complete desinfiltration (n = 6) of all papulonodular skin lesions was observed with marked improvement of lymphedema in 6 patients. According to the AIDS Clinical Trials Group criteria, response was partial in 100% of patients. A major response was obtained among patients who had visceral lesions (n = 3 patients), with rapid and complete remission of digestive or respiratory symptoms. The mean delay to response was 2 courses. Treatment was sustained for 3 patients. For the remaining 9 patients who received a median of 7 courses (range, 2-14 courses), the mean time to recurrence or follow-up without recurrence was 13 months. Tolerance was good except for 3 episodes of Grade 3 or 4 asymptomatic neutropenia and 1 episode of moderate myositis.

CONCLUSIONS

The results of this study showed that taxanes are beneficial in the treatment of patients with refractory or life-threatening Kaposi sarcoma.

Aggressive Behavior of Classical Kaposi's Sarcoma and Coexistence With Angiosarcoma

An 82-year-old Caucasian man presented with initially asymptomatic livid red plaques on the plantar surface of the feet that become confluent and evolved into invasively growing nodules accompanied by massive edema. Histology allowed a diagnosis of the classical form of Kaposi's sarcoma; the serology test result for HIV was negative, whereas the associated human herpes virus type 8 was detected by polymerase chain reaction on the skin sample. Over the subsequent 6 months, skin lesions become vegetative and partially necrotic, and extended to the hands and eyelids. Chemotherapy with vinblastine appeared to stabilize the cutaneous disease, but the patient developed a massive gastrointestinal hemorrhage secondary to dissemination to the stomach. Twelve months after the onset of the disease, vegetative and easily bleeding lesions progressively occluded the mouth of the patient: histological features were consistent with a low-grade angiosarcoma distinct from that of Kaposi's sarcoma. The patient could not chew and swallow anymore; he was put on an artificial nutrition but died shortly thereafter. This case illustrates that, even in its classical form, Kaposi's sarcoma may be a malignant, rapidly progressing tumor.

LEARNING POINTS

a) The extent and rate of spread of initial skin lesions should be considered to be early signs of aggressive dissemination, even in the absence of other variables (i.e., histological pattern, human herpes virus type 8 positive mononuclear cells) associated with progression of the disease. b) An endoscopy may be useful given the high prevalence of gastrointestinal involvement. c) When classical Kaposi's sarcoma displays aggressive behavior a second, primary malignant tumor arising from the vascular tissue should be investigated.

TAKE-HOME MESSAGE

Even in its classical form, Kaposi's sarcoma may be a malignant, rapidly progressing tumor with visceral involvement; also, a second malignancy may occur in nearly one patient of four. Because localized skin lesions can regress completely with radiotherapy, watchful waiting is probably inappropriate in most cases.

AIDS-related cancer in the era of highly active antiretroviral therapy (HAART): a model of the interplay of the immune system, virus, and cancer. "On the offensive--the Trojan Horse is being destroyed"--Part A: Kaposi's sarcoma

The introduction of highly active antiretroviral therapy (HAART), aimed at controlling human immunodeficiency virus (HIV), has been associated with a dramatic decrease in the incidence of acquired immunodeficiency syndrome-Kaposi's sarcoma (AIDS-KS) and the clinical manifestations of KS appear to be less aggressive. The pathogenesis of AIDS-related KS is related to a system of cytokines (e.g., interleukin-6) driven by autocrine and paracrine loops. More recently, human herpesvirus 8 (HHV-8), was discovered to be the putative etiological agent of this disease. This virus encodes several unique open reading frames that are homologs of human cellular proteins involved in cellular regulations, cell proliferation, apoptosis, and immune regulation. The treatment of this disease depends on whether it is "limited" disease or "extensive" disease. For "limited" disease, local therapy or non-bone marrow suppressive agents should be used. For "extensive" disease, new chemotherapeutic agents, such as liposomal anthracycline, which are active and have little adverse reactions, are indicated. The control of HIV infection continues to be essential. Knowledge of the pathogenesis of the disease has led to the development of novel treatment strategies, aimed at the inflammatory or angiogenesis cytokines necessary for growth or at HHV-8 as the target of therapy.

A new superinvasive in vitro phenotype induced by selection of human breast carcinoma cells with the chemotherapeutic drugs paclitaxel and doxorubicin

Doxorubicin- and paclitaxel-selected variants of an in vitro invasive clonal population of the human breast cancer cell line, MDA-MB-435S, were established by pulse selection, and exhibited a novel ‘superinvasive’ phenotype. This phenotype is characterised by an ability to relocate to another surface following invasion through matrigel and membrane pores, by decreased adhesion to extracellular matrix proteins and by increased motility. This may represent an in vitro model of a step in the metastatic process occurring subsequent to invasion. The paclitaxel-resistant variants, MDA-MB-435S-F/Taxol-10p and MDA-MB-435S-F/Taxol-10p4p were resistant to paclitaxel, vincristine and docetaxel, but not to doxorubicin, carboplatin, etoposide or 5-fluorouracil. The doxorubicin-selected variants MDA-MB-435S-F/Adr-10p and MDA-MB-435S-F/Adr-10p10p, in contrast, exhibited only small increases in resistance to doxorubicin, although they were slightly resistant to VP-16 and docetaxel, and exhibited increased sensitivity to paclitaxel, carboplatin and 5-fluorouracil.

Expression cloned cDNA for 10-deacetylbaccatin III-10-O-acetyltransferase in Escherichia coli: a comparative study of three fusion systems

10-Deacetylbaccatin III-10-O-acetyltransferase (10-DABT) catalyzes the formation of baccatin III, which is an immediate diterpenoid precursor of Taxol. A cDNA encoding 10-DABT was cloned from Taxus baccata by using RT-PCR and screening a cDNA library. A study of its heterologous overexpression in Escherichia coli was carried out. To get high-level expression of recombinant enzyme, three kinds of IPTG inducible fusion expression systems (with glutathione S-transferase (GST), hexahistidine (6x His), and biotinylated tag) were used, and results of expression were compared. Fusion 10-DABT with different tags was expressed with diverse expression levels and solubility in the three systems. Optimum IPTG concentration, temperature, and inducing time for producing recombinant enzymes were found. Under higher IPTG concentration (up to 1 mM), the highest level of expression for fusion protein was obtained in the 6x His fusion system with phage T5 promoter, but expressed products were only partially soluble. With lower IPTG concentration (less than 0.5 mM), the highest expression was detected in the GST fusion system with tac promoter, and the lowest level of expression appeared in the biotinylated fusion system. The expression level in the latter system did not differ dramatically with a range of different inducer concentrations. GST and 6x His fusion proteins were mainly soluble in aqueous solutions and Triton X-100 improved the solubility of biotinylated fusion proteins (inferring this protein is membrane-associated). Fusion proteins could only be partially purified by a single affinity chromatography step for all three systems. Glutathione-coupled matrix and streptavidin-conjugated resin have higher specificity than Ni-NTA resin, and elution conditions were shown to affect enzyme activity. Three kinds of recombinant 10-DABT with different tags showed enzyme activity, but total enzyme activity was lost as a result of the affinity chromatography step. Thrombin and Factor Xa could be used for site-specific cleavage of fusion proteins, but the incubation temperature affected enzyme activity of recombinant enzymes.

Paclitaxel for anthracycline-resistant AIDS-related Kaposi's sarcoma: clinical and angiogenic correlations

BACKGROUND

Murine data indicate that angiogenesis is central to the aetiopathogenesis of Kaposi's sarcoma (KS). Therefore, we measured angiogenic cytokines and growth factors in patients with AIDS-related KS during treatment with both antiretrovirals and second-line paclitaxel chemotherapy. Cytokines measured included tumour necrosis factor-alpha (TNF-alpha), basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF) and the interleukins IL-2, -6 and -12.

PATIENTS AND METHODS

Enzyme-linked immunosorbent assays (ELISAs) were carried out to measure plasma cytokine levels in 17 patients with AIDS-related KS who had progressed within 6 months of receiving liposomal anthracyclines and were treated with paclitaxel 100 mg/m(2) every 2 weeks. Measurements were carried out before progression, at commencement and at the completion of paclitaxel.

RESULTS

The objective response rate to paclitaxel was 71% (95% confidence interval 60% to 81%). In 17 patients with AIDS-related KS, we observed eight partial responses and four complete responses. Patients with AIDS Clinical Trial Group stage T1 disease had higher plasma VEGF (P = 0.05) and lower plasma TNF-alpha levels (P = 0.05) than patients with earlier stage T0 KS. There were no correlations between plasma cytokines (bFGF, VEGF, TNF-alpha, and IL-2,-6 and -12) and the CD4 and CD8 cell counts or HIV-1 RNA viral load. Response to paclitaxel was associated with a fall in plasma IL-6 levels (P = 0.04) but no change in other cytokines. There were no significant changes in CD4, CD8, CD16/56, CD19 cell counts and HIV-1 viral loads during chemotherapy.

CONCLUSIONS

Angiogenic cytokines may correlate with KS disease extent but not with cellular immune function or HIV viraemia. Response to paclitaxel therapy correlates with a fall in plasma IL-6 levels and recent data indicate this may be a surrogate marker of KS-associated herpesvirus viral load. Overall, clinical response in KS correlates poorly with known angiogenic cytokines.

Histological characterization of regression in acquired immunodeficiency syndrome-related Kaposi's sarcoma

BACKGROUND

Kaposi's sarcoma (KS) is an angioproliferative lesion that may regress or progress. Progression is related to spindle cell proliferation and the expression of human herpes virus-8 latency genes, including latent nuclear antigen-1 (LNA-1), cyclin-D1, and bcl-2. KS regression has not been well characterized histologically. Therefore, this study was undertaken to characterize the histopathology of pharmacologically induced regressed cutaneous KS.

METHODS

Skin punch biopsies from eight patients with acquired immunodeficiency syndrome (AIDS)-related KS, that regressed following chemotherapy with paclitaxel or the angiogenesis inhibitor Col-3, were investigated by light microscopy. Comparative immunophenotyping on pre- and post-treatment specimens for CD31, LNA-1, cyclin-D1, bcl-2, and CD117 (c-kit) was performed.

RESULTS

Clinical and histologic features of regression were similar for paclitaxel and Col-3 treatment. On clinical examination, lesions flattened, became smaller, and lost their purple-red appearance, resulting in an orange-brown macule. Histological regression was divided into partial (n = 3) and complete (n = 5) regression. Partially regressed lesions had a significant reduction of spindle cells in the dermal interstitium, with residual spindle cells arranged around superficial and mid-dermal capillaries. Complete regression was characterized by an absence of detectable spindle cells, with a slight increase in capillaries of the superficial plexus. All regressed samples exhibited a prominent, superficial, perivascular, lymphocytic infiltrate and abundant dermal hemosiderin-laden macrophages. This clinicopathologic picture resembled the findings of pigmented purpura. CD31 staining correlated with the reduction of spindle cells. Regression was accompanied by a quantitative and qualitative decrease in LNA-1 and cyclin-D1 immunoreactivity, but no change in bcl-2 or c-kit expression.

CONCLUSIONS

Pharmacologically induced regression of AIDS-related cutaneous KS is characterized by a complete loss or decrease of spindle cells, increased lymphocytes, and prominent dermal siderophage deposition. Without any prior knowledge of the history of KS regression following therapy, regressed KS lesions may be misdiagnosed clinically and histologically as pigmented purpuric dermatitis.

Use of HIV protease inhibitors to block Kaposi's sarcoma and tumour growth

HIV protease inhibitors are antiretroviral drugs that block the enzyme required for production of infectious viral particles. Although these agents have been designed to selectively bind to the catalytic site of HIV protease, evidence indicates that other cellular and microbial enzymes and pathways are also affected. It has been reported that patients treated with highly active anti-retroviral therapy (HAART) containing a protease inhibitor may be at reduced risk of Kaposi's sarcoma (KS) and some types of non-Hodgkin lymphomas; some disease regressions have also been described. Here we review recent data showing that several widely used protease inhibitors, including indinavir, saquinavir, ritonavir, and nelfinavir, can affect important cellular and tissue processes such as angiogenesis, tumour growth and invasion, inflammation, antigen processing and presentation, cell survival, and tissue remodelling. Most of these non-HIV-related effects of protease inhibitors are due to inhibition of cell invasion and matrix metalloprotease activity, or modulation of the cell proteasome and NFkappaB. These elements are required for development of most tumours. Thus, by direct and indirect activities, protease inhibitors can simultaneously block several pathways involved in tumour growth, invasion, and metastasis. These findings indicate that protease inhibitors can be exploited for the therapy of KS and other tumours that occur in both HIV-infected and non-infected individuals. A multicentre phase II clinical trial with indinavir in non-HIV-associated KS is about to start in Italy.

HIV protease inhibitors as new treatment options for Kaposi's sarcoma

A reduced incidence and regression of Kaposi's sarcoma (KS) and other tumours has been reported in Acquired Immune Deficiency Syndrome (AIDS) patients treated with antiretroviral combination therapies containing Human Immunodeficiency Virus (HIV) protease inhibitors (PIs) such as indinavir or saquinavir. Indeed, evidence indicates that although PIs were designed to selectively inhibit the HIV protease activity, they can interfere with several cellular pathways and can inhibit tumour growth. In particular, our recent results indicate that doses of indinavir or saquinavir similar to those employed to treat AIDS patients can induce regression of experimental KS by directly blocking two fundamental steps of KS initiation and progression: new blood vessel formation (angiogenesis) and KS tumour cell invasion. This is because indinavir or saquinavir inhibit the activation of matrix metalloproteinase-2 (MMP-2), a basement membrane-degrading enzyme, which is required for the progression of most tumours. Based on these results, a multicentre clinical trial is now starting in Italy, which will assess PI effects on the progression of KS in HIV-uninfected individuals (classical KS).

Viral versus cellular BCL-2 proteins

All gamma herpesviruses and a few other viruses encode at least one homologue of the mammalian cell death inhibitor BCL-2. Gamma herpesviruses are associated with human and animal lymphoid and epithelial tumours. However, the role of these viral BCL-2 homologues in the virus replication cycle or in human disease is not known, though recent developments show progress in this area. The structure of viral BCL-2 family protein, KSBcl-2, is similar to that of cellular family members, but viral BCL-2 proteins differ functionally from the cellular proteins, apparently escaping the regulatory mechanisms to which their cellular counterparts are subjected. Thus, exploring the biochemical and biological functions of the viral BCL-2 family proteins will increase our understanding of their role in virus infections and will undoubtedly teach us something about their cellular kin.

Treatment of Kaposi's sarcoma--an update

Kaposi's sarcoma (KS) is an angioproliferative disease of multifactorial origin arising in different clinic-epidemiologic forms, which show the same histopathological features. It generally starts as a hyperplastic reactive-inflammatory and angiogenic process, which may evolve into monomorphic nodules of KS cells that can be clonal (late-stage lesions) and resemble a true sarcoma. Infection with the human herpesvirus 8, cytokine- and angiogenic factor-induced growth together with an immuno-dysregulated state represent fundamental conditions for the development of this tumor. Several local therapies are used to eradicate early and confined skin lesions, whereas widely disseminated, progressive or symptomatic disease requires a more aggressive treatment. Although different chemotherapeutic agents have been used to treat aggressive KS, the growing understanding of the pathogenetic factors participating in KS development has provided a strong rationale for using less- or non-cytotoxic agents that block the mechanisms involved in KS pathogenesis. The angiogenic nature of KS makes it particularly suitable for using therapies based on anti-angiogenic agents. Of note on this goal, recent studies indicate that the highly active anti-retroviral therapy, including at least one human immunodeficiency virus (HIV) protease inhibitor (PI), is associated with a dramatic decrease in the incidence of AIDS-KS and with a regression of KS in treated individuals. Consistent with this, results from preclinical studies indicate that PIs have potent and direct anti-angiogenic and anti-KS activities, suggesting that they should be further investigated, alone or combined with other therapies, as a novel treatment for KS in both HIV seropositive or seronegative individuals.

Interleukin-8 and growth-regulated oncogene alpha mediate angiogenesis in Kaposi's sarcoma

The development of the complex neoplasm Kaposi's sarcoma is dependent on infection with the Kaposi's sarcoma-associated herpesvirus (KSHV) and appears to be greatly enhanced by cytokines and human immunodeficiency virus type 1 (HIV-1) Tat. Interleukin-8 (IL-8) and growth-regulated oncogene alpha (GRO-alpha) are chemokines involved in chemoattraction, neovascularization, and stimulation of HIV-1 replication. We have previously demonstrated that production of GRO-alpha is stimulated by exposure of monocyte-derived macrophages (MDM) to HIV-1. Here we show that exposure of MDM to HIV-1, viral Tat, or viral gp120 leads to a substantial increase in IL-8 production. We also demonstrate that IL-8 and GRO-alpha are induced by KSHV infection of endothelial cells and are crucial to the angiogenic phenotype developed by KSHV-infected endothelial cells in cell culture and upon implantation into SCID mice. Thus, the three known etiological factors in Kaposi's sarcoma pathogenesis-KSHV, HIV-1 Tat, and cellular growth factors-might be linked, in part, through induction of IL-8 and GRO-alpha.

Successful treatment of post-renal transplant Kaposi's sarcoma with paclitaxel

Kaposi's sarcoma (KS) is a complication of immunosuppressive therapy for renal transplant recipients. Treatment is usually withdrawal of immunosuppression; nonresponders often receive chemotherapy. Successful treatment with single agent paclitaxel (PTX) has been documented in only one patient. We report two patients with generalized cutaneous, and visceral KS, which progressed despite withdrawal of immunosuppressive therapy, and were treated with weekly PTX. Both patients' KS regressed completely after four courses of PTX, and remained in remission for > 1 year. PTX may be important in the treatment of post-transplant KS resistant to withdrawal of immunosuppressive therapy.