Tumorigenesis and metastasis of neoplastic Kaposi's sarcoma cell line in immunodeficient mice blocked by a human pregnancy hormone

HHV8 and female Kaposi's sarcoma

Kaposi's sarcoma (KS) is an enigmatic tumour of uncertain histogenesis. Epidemiological data have long suggested that KS may be caused by an infectious agent, possibly sexually transmitted. Following the documentation of human herpesvirus 8 (HHV8) and its strong association with all forms of KS, it now appears that the putative agent has at last been identified. As KS is rare in females, a unique group was screened for the presence of HHV8 using both conventional solution-phase polymerase chain reaction (PCR) and the newly described technique of TaqMan PCR. The presence of HHV8 was demonstrated in 10/12 of these female patients. This further supports the direct role of HHV8, in conjunction with cytokines and other factors, in the pathogenesis of KS.

Identification of HHV-8 DNA in the skin lesions of Kaposi's sarcoma in an immunosuppressed patient with bullous pemphigoid

Kaposi's sarcoma rarely occurs as an opportunistic tumor in iatrogenically immunosuppressed patients. We describe the clinical presentation, treatment of Kaposi's sarcoma skin lesions in an immunosuppressed patient with bullous pemphigoid. Using the polymerase chain reaction, HHV-8 DNA was detected in two separate Kaposi's sarcoma lesions but not in control tissues. The amplified DNA fragments derived from our patient's Kaposi's sarcoma skin lesions contained unique point mutations that distinguished the virus isolated from Kaposi's sarcoma lesions derived from other patients. This is the first demonstration that HHV-8 DNA is associated with Kaposi's sarcoma skin lesions in an HIV-negative, immunosuppressed patient with bullous pemphigoid. HHV-8 is probably a common latent herpesvirus that is activated by immunosuppressive therapy in genetically predisposed patients and may be involved in the pathogenesis of Kaposi's sarcoma.

The role of carboxy-terminal portion of beta subunit of human chorionic gonadotropin in human immunodeficiency virus infection

Human chorionic gonadotropin (hCG) and the beta subunit of this dimer glycoprotein hormone (beta hCG) have been reported by us to inhibit HIV replication. In order to identify the active site responsible for the antiviral activity, twelve overlapping peptides spanning across beta hCG were examined for their effect against HIV-caused cell death. Although the NH2-terminus of beta hCG appeared to contribute to activity, the core region was biologically inert. The most potent activity was observed with the fragment representing the carboxy-terminus of beta hCG. The dose response curve to serial dilutions of the peptide, containing amino acid residues 106-145, had a bell-shaped appearance - characteristic of hCG and beta hCG. The peak of activity corresponded to 100 ng/ml - the dose at which two thirds of virus-exposed MT-4 T lymphocytes survived. None of the tested peptides were toxic to MT-4. While the mechanism of action remains unclear, the results suggest that the COOH-terminal portion, unique to beta hCG, confers anti-HIV activity.

Effects of hCG and beta-hCG on IL-2 and sIL-2R secretion from human peripheral blood mononuclear cells: a dose-response study in vitro

The effects of human chorionic gonadotropin (hCG) as well as beta-subunit of hCG (B-hCG) in concentrations of: 80,000/25,000; 500; 50; 5 mIU/ml on in vitro release of interleukin-2 (IL-2) and soluble interleukin-2 receptor (sIL-2R) from resting or phytohemagglutinin (PHA) activated human peripheral blood mononuclear cells (PBMC) were studied. Both the interleukins were measured in supernatants of human PBMC by quantitative sandwich enzyme immunoassay method (ELISA). We found that hCG in the dilutions of 80,000 mIU/ml (P < 0.01) and 5 mIU/ml (P < 0.05) diminished IL-2 secretion only from PHA activated PBMC. beta-hCG in concentrations of 5 mIU/ml (P < 0.05), 500 mIU/ml (P < 0.01) and 25,000 mIU/ml (P < 0.05) also diminished IL-2 secretion from PHA activated PBMC, and only in a dilution of 25,000 mIU/ml (P < 0.05) from resting PBMC. Simultaneously, hCG in concentration of 80,000 mIU/ml (P < 0.01) potentiated the release of sIL-2R into supernatants from resting and PHA activated PBMC, but in concentration of 50 mIU/ml (P < 0.05) slightly depressed the secretion of IL-2 from PHA activated PBMC cultures. beta-hCG in dilution of 25,000 mIU/ml (P < 0.001) stimulated the release of sIL-2R from resting or PHA activated PBMC. beta-hCG had also inhibitory effect on sIL-2R secretion from resting (in a dilution of 50 mIU/ml; P < 0.05) and PHA activated (500 mIU/ml; P < 0.01) PBMC. The inhibitory effect of very high concentrations of hCG and beta-hCG on IL-2 secretion together with their stimulatory effect on sIL-2R release from PBMC may be an important event during the human pregnancy and various cancers.

Human immunodeficiency virus (HIV)-related pulmonary complications in pregnancy

With changes in the demographics of human immunodeficiency virus (HIV) infection, women and children are becoming the fastest growing group of newly infected patients. With longer survival after HIV infection, more women infected with HIV are becoming pregnant. Pulmonary disease is one of the most common presenting conditions in an AIDS-defining illness. Pneumocystis carini pneumonia and tuberculosis are the most common disorders that herald the onset of AIDS. They are also the most frequently encountered HIV-related pulmonary complications during pregnancy. Others have been rarely reported during pregnancy and include fungal infections (Cryptococcus neoformans, Histoplasma capsulatum, and Coccidioides immitus), bacterial infections (Haemophilus influenzae and Streptococcus pneumoniae along with Pseudomona aeruginosa), viral infections (CMV), opportunistic neoplasms (Kaposi's sarcoma, lymphoma) and miscellaneous conditions peculiar to HIV-infected individuals (nonspecific interstitial pneumonitis, lymphoid interstitial pneumonitis, isolated pulmonary hypertension, and pulmonary edema secondary to cardiac disease or drug abuse). Most of the data regarding the pulmonary complications of HIV infection come from studies in nonpregnant patients. The extent to which pregnancy affects the course of respiratory disease in HIV infection and vice versa is not well documented. Clinical presentation is usually not altered by pregnancy. Except for minor modifications mainly related to potential fetal effects, the diagnostic work-up and management are similar to those in the nonpregnant patient. The most important effect of pregnancy on these conditions remains the delay in diagnosis and treatment. A high index of suspicion should, therefore, be maintained. In addition, most prophylactic measures recommended in nonpregnant HIV-infected individuals also apply to pregnant women.

The beta-core fragment of human chorionic gonadotrophin inhibits growth of Kaposi's sarcoma-derived cells and a new immortalized Kaposi's sarcoma cell line

OBJECTIVE

Kaposi's sarcoma (KS), a condition often associated with HIV infection, is more common in men than in women; pregnancy and sex hormones could be involved. Urinary human chorionic gonadotrophin (hCG) has been reported to inhibit the growth of KS cell lines, with great variability among preparations. Urinary hCG often contains free forms of the hCG subunits and a fragment of the free beta-subunit, the beta-core, which may have biological activity. We compared the effect of the beta-core fragment, the beta-subunit, recombinant and urinary hCG on KS immortal and spindle cells.

DESIGN AND METHODS

A new immortal KS cell line was phenotypically and karyotypically characterized. The effects on growth of this cell line and of primary KS spindle cells by hCG and its purified derivatives were tested. Induction of apoptosis was demonstrated using acridine orange/ethidium bromide staining.

RESULTS

The beta-core fragment harboured the most potent growth inhibitory activity on a molar basis. After 72 h of treatment with the beta-core, 60-70% of KS cells show apoptotic nuclei. No effects were observed on endothelial cells.

CONCLUSIONS

The beta-core fragment of hCG proved to be the most effective part of the hCG molecule, inducing growth inhibition and apoptosis of KS cells. Thus, the beta-core could be the most appropriate hCG derivative for the therapy of KS.

Etiology of AIDS-related Kaposi's sarcoma and lymphoma

Kaposi's sarcoma (KS) and non-Hodgkin's lymphomas (NHL) are common consequences of HIV infection. These tumours appear to be precipitated by herpesviruses. Epstein-Barr virus (EBV) is implicated as a cause of up to 50% of systemic NHLs and up to 100% of central nervous system lymphomas in patients with AIDS. KS may be a consequence of the newly identified gamma-herpesvirus KSHV (KS-associated herpesvirus or HHV-8). This herpesvirus is found in all KS biopsies from different epidemiologic forms of this disease. KSHV is also implicated in the pathogenesis of a rare form of B cell lymphoma called body-cavity based lymphoma or primary effusion lymphoma (PEL).

Human chorionic gonadotropin hormone prevents wasting syndrome and death in HIV-1 transgenic mice

At birth, transgenic mice, homozygous for the HIV-1 provirus pNL4-3, deleted in gag/pol, are normal in appearance and weight. Within several days after birth, the pups develop a syndrome characterized by dry, scaly, hyperkeratotic skin, growth failure, and death. The possibility that the homozygous embryos are being protected during gestation by a maternal factor led us to treat the newborn animals with various pregnancy-related hormones including human chorionic gonadotropin (hCG), estrogen, progesterone, and dexamethasone. Treatment with hCG prevented death, led to normal growth, and markedly reduced skin lesions. In contrast to the skin of the untreated homozygous pups, which expressed high levels of HIV mRNA and proteins (i.e., gp120 and Nef), the skin of the hCG-treated pups showed a marked reduction in both HIV mRNA and proteins. Discontinuation of hCG resulted in the reappearance of HIV transcripts and proteins, skin lesions, and growth failure resulting in death. In addition, HIV transcripts and proteins were reduced significantly in heterozygous mothers during pregnancy, but reappeared after parturition. Similarly, hCG treatment resulted in a decrease of HIV proteins in the skin of nonpregnant heterozygous transgenic mice. These findings suggest that the inhibiting effect of hCG on HIV expression may be clinically useful in the treatment of HIV infections, and may be responsible, during pregnancy, for the low transmission of HIV from infected mothers to their offspring.

Survival of European patients with Kaposi's sarcoma as AIDS-defining condition during the first decade of AIDS. AIDS in Europe Study Group

OBJECTIVES

To determine whether the survival of patients with Kaposi's sarcoma as first manifestation of AIDS has changed between 1979 and 1989; and to define whether prognosis factors could be identified.

PATIENTS AND METHODS

This is a multicentric retrospective cohort study from 52 centers in 17 European countries involving adults AIDS patients diagnosed between 1979 and 1989. Variables such as age, sex, geographical regions, transmission groups, date of Kaposi's sarcoma diagnosis, zidovudine use, CD4+ cell count and concomitant opportunistic infections or AIDS-related malignancies were evaluated by using uni- and multivariable proportional hazard models. Log-rank tests were used to determine which variables were associated with survival.

RESULTS

From the 6,546 AIDS patients recruited in the database of the AIDS in Europe Study Group, 1,394 were diagnosed with Kaposi's sarcoma at the time of AIDS diagnosis, from 1979 and 1989. A total of 1,047 Kaposi's sarcoma patients died during the follow-up period. By Kaplan-Meier analyses, the median and mean survival for these Kaposi's sarcoma patients were 17 and 25 months, respectively, with no change over time. However, age, sex (female), geographic region, low CD4+ cell count (< 150 x 10(6)/l) and some opportunistic infections and non-Hodgkin's lymphoma were associated with a poorer prognosis. Zidovudine use, year of diagnosis and risk factor for HIV-1 infection brought no additional information as predictor of mortality.

CONCLUSIONS

This study suggests that the survival of patients with Kaposi's sarcoma as first manifestation of AIDS has remained poor during the last decade in contrast with the overall AIDS survival which had significantly improved from a median of 13-18 months during the same period of observation. There is a need for further prospective information to explain the worse prognosis in women and the geographical variations.

Acquired immunodeficiency syndrome-associated Kaposi's sarcoma. Biology and management

Kaposi's Sarcoma (KS), the most common AIDS-associated malignancy, occurs with increased frequency in all HIV transmission groups, but at a particularly high rate in homosexual men. Recent studies suggest that KS pathogenesis involves exposure to an infectious agent, altered expression and response to cytokines, and modulation of growth by HIV gene products. KS varies in its clinical presentation from a relatively indolent process to a widely disseminated, aggressive disease. A variety of local and systemic treatments provide effective, but usually temporary, disease palliation. Insights into KS pathogenesis suggest a number of targeted therapeutic approaches that may eventually lead to improved disease management and disease cure.

Strain variability among Kaposi sarcoma-associated herpesvirus (human herpesvirus 8) genomes: evidence that a large cohort of United States AIDS patients may have been infected by a single common isolate

Previous analysis of the majority of Kaposi's sarcoma (KS) tumors, in both AIDS and non-AIDS populations, has revealed the consistent presence of two small subsegments (open reading frame 25/26 [ORF25/26] and ORF75) of a novel human gamma class herpesvirus genome referred to as KSHV or HHV-8. We have carried out DNA sequence comparisons with DNAs encompassing a total of 2,500 bp each over three separate PCR-amplified fragments from KS lesions and body cavity-based lymphoma (BCBL) samples from 12 distinct patients, including four African and two classical or endemic non-AIDS KS samples. The results revealed differences at 37 of 2,500 nucleotide positions (i.e., 1.5% overall variation). However, the 12 HHV-8 genomes examined fell into three distinct but very narrow subgroupings (A, B, and C strains). All A strain isolates differed from B strain isolates at 16 positions, but of the eight U.S. samples tested, six were A strains, and these differed at no more than two positions among them. Similarly, three of the four African samples were B strains, which differed from each other at only one position. The two C strain genomes also displayed only one nucleotide variation, but they differed from all A strains at 26 positions and from all B strains at 20 positions. One C strain genome was present in all six independent lesions from an AIDS KS patient with disseminated disease, and the other represented a mosaic A/C recombinant genome from the HBL6 cell line derived from a BCBL tumor. Evaluation of previous data suggests that B and C strains may predominate in Africa and that A strains predominate in classical Mediterranean samples. Although both B and C strains are represented in U.S. AIDS patients, the majority (70 to 80%) of samples from the mid-East Coast region at least appear to be virtually identical, supporting the concept that they may all derive from the spread during the AIDS epidemic of a single recently transmitted infectious agent.

Advances in Kaposi's sarcoma

KS remains a challenge to clinicians and investigators more than a century after its initial description. Debate continues as to the cell of origin, as well as whether or not it is a true cancer. KS appears to be an opportunistic neoplasm, which in its earliest phase retains some features of a benign hyperproliferative process, but in its late stages behaves like an aggressive malignancy. Pathogenesis seems to involve a predisposed individual (genetically susceptible or immunologically compromised) who comes into contact with an infectious agent, most likely a virus. Cytokines appear to play a major role in the growth of the tumor. The exact role of the KSHV in this process will likely be the subject of much investigation in the future.

Kaposi's sarcoma and its management in AIDS patients. Recommendations from a Scandinavian Study Group

KS is the most frequent malignancy in homo/bisexual male AIDS patients, affecting more than 30% of these patients. KS may present itself as a few innocent cutaneous lesions or may show progression resulting in severe morbidity and mortality. Approximately half of the patients may develop severe progressive disease. The prognosis of patients with progressive disease is poor, with a median survival of less than 6 months. There is no cure for AIDS-related KS, but several therapies are available for palliation. The treatment options may be applied locally or systemically. Radiotherapy is efficacious and safe, but only a few lesions may be treated at one time. For severe progressive KS, systemic therapy with various forms of chemotherapy is used. Three regimes in particular have been focused on, namely bleomycin/vincristine (BV), doxorubicin + BV (DBV), or liposomal daunorubicin (LD) administered every 2 weeks. The agents result in a clinically relevant response (in 50-80% of patients) 2-4 weeks after initiation, but few patients have complete remission of the KS (< 10%), and the tumour may relapse after 4-6 months despite continued therapy. BV is less effective but also less toxic compared with the other regimens. Time to response for DBV may be slightly better than for LD, but the overall efficacy of these 2 regimes is similar. LD treatment is associated with significantly fewer episodes of peripheral neuropathy and alopecia than treatment with DBV. Thus, the recommended order of use of chemotherapeutic agents is BV, LD and DBV. Alpha-interferon may have a role in the small percentage of patients with CD4 cell count > 200 mill/L. In conclusion, several therapeutic options are available for palliation of KS. All systemically applied therapies are associated with severe side-effects and the optimal choice of treatment is a careful balance between response and toxicity. The recent discovery of human herpes virus 8 as a putative causative agent for KS and new potent groups of anti-retroviral agents, may lead to the development of more effective treatments of KS.

Survival of classic Kaposi's sarcoma and risk of second cancer

In order to elucidate survival rates and risk of second primary cancer, we assessed 204 patients with histologically confirmed classic Kaposi's sarcoma (KS) who were identified in 11 Italian population-based cancer registries. One hundred and thirty-nine were men (median age 70 years) and 65 were women (median age 72). One, 5 and 10 year survival rates were 0.92, 0.69 and 0.46 respectively. Median survival was 9.4 years (i.e. not different from the Italian general population of the same sex and age). Survival did not vary according to sex and tumour site (i.e. lower limbs only or other). Eleven second primary cancers, including two lung and two kidney cancers, were reported after KS diagnosis (not different from the expected number).

Endocrinologic complications of HIV infection

A variety of endocrine disorders occur in HIV-infected patients. The abnormalities may be a consequence of HIV infection, or may result from opportunistic infections, associated malignancies, illness-associated cytokine production, or use of therapeutic agents. Observations and controversies concerning adrenal, gonadal, thyroidal, and metabolic abnormalities are discussed. Heightened awareness of problems that might otherwise be overlooked will permit timely diagnosis and treatment of identified problems, which will enhance and potentially prolong the lives of people infected with HIV.

The effects of preparations of human chorionic gonadotropin on AIDS-related Kaposi's sarcoma

BACKGROUND

Kaposi's sarcoma is the most common cancer in patients with the acquired immunodeficiency syndrome (AIDS). Recently, certain preparations of human chorionic gonadotropin (hCG) have been shown to inhibit the growth of Kaposi's sarcoma cell lines in vitro and in immunodeficient mice.

METHODS

After in vitro evaluation of four commercially available hCG preparations, the most active product was evaluated in 36 patients with AIDS-related Kaposi's sarcoma. In a phase 1-2 trial, 24 patients received intralesional injections of hCG three times a week for two weeks at doses of 250, 500, 1000, or 2000 IU (6 patients each). In each patient three nodular lesions were injected, two with the drug and one with diluent alone. In a double-blind trial, 12 additional patients were randomly assigned to receive intralesional injections of 2000 IU of hCG or diluent alone (6 patients each; two lesions per patient). At the conclusion of therapy, the lesions were measured, their gross appearance assessed, and biopsy specimens evaluated.

RESULTS

A.P.L. (Wyeth-Ayerst), which had the most in vitro activity against Kaposi's sarcoma cell lines, was selected for the clinical investigation. Treatment with A.P.L. was well tolerated at all doses. In the cohorts given 250, 500, 1000, and 2000 IU, 1, 5, 5, and 10 of the 12 injected lesions responded, respectively (P=0.03 for trend). Complete tumor regression was observed in one lesion each at the 250-IU and 500-IU doses, in two lesions given the 1000-IU dose, and in five lesions given the 2000-IU dose. In the double-blind study, none of the 12 lesions in the six patients injected with diluent had responses, as compared with 10 of the 12 lesions in the six patients injected with hCG (P=0.015). Microscopical evidence of apoptosis was observed only in hCG-treated lesions. The percentage of cells that died increased in a dose-dependent manner (P<0.001). Serum levels of follicle-stimulating hormone (P=0.002) and luteinizing hormone (P=0.001) declined after the last injection of hCG, but there was no effect on these hormones in the diluent-treated patients.

CONCLUSIONS

The intralesional injection of hCG induces the regression of AIDS-related Kaposi's sarcoma lesions in a dose-dependent manner. The response of these tumors appears to be mediated by the induction of apoptosis.

Structure-function studies of human TSH: new advances in design of glycoprotein hormone analogs

Recent progress in structure-function studies of glycoprotein hormones has provided new insights into the molecular mechanisms of action of these hormones and has further supported the concept that physiological modulation of assembly, bioactivity, and clearance of these hormones is dependent on specific structural components. This review emphasizes current advances in the structure-function relationships of human TSH, which have contributed to further elucidation of common and hormone specific features within the glycoprotein hormones family. Novel strategies are now being applied to investigate the role of individual structural elements. The principks discovered in such studies are essential to understand the physiological regulation of hormone bioactivity and allow for the rational design of novel analogs with potential therapeutic applications.

AIDS-related Kaposi's sarcoma. A template for the translation of molecular pathogenesis into targeted therapeutic approaches

AIDS-related Kaposi's sarcoma (KS) represents a complex interaction of host and viral factors. There are a number of fundamental questions surrounding the interplay between the disparate factors that can contribute to the pathogenesis and pathophysiology of this disease. Targets such as the enhancement of immune function, inhibition of angiogenic factors or immunostimulatory cytokines, inhibition of viral proteins such as Tat, or hormonal manipulations are now or will in the future become the focus of research to develop innovative anti-KS therapy and prevention measures. Antiviral approaches aimed at HIV or other viruses may potentially target a number of steps in KS pathogenesis. This article reviews diverse modalities--cytotoxic, antiviral, gene-directed, growth factor-targeted, and antiangiogenesis--that singly, or more likely in combination, stand to make an impact on the cure and prevention of AIDS-related KS.

Absence of human herpesvirus 8 DNA sequences in neoplastic Kaposi's sarcoma cell lines

The recent detection of herpesvirus-like DNA sequences in Kaposi's sarcoma (KS) lesions has led to numerous speculations regarding the role of this new agent in KS pathogenesis. However, recent studies indicate a far wider distribution of such viral sequences, shadowing the potential etiologic role of this agent in KS. In this report we show that malignant KS cell lines do not harbor such viral sequences while B cells, CD14+ and CD34+ cells do, suggesting that if a KS malignancy originates from infection with HHV-8, the virus can be lost and is not necessary for maintenance of the neoplastic state. Alternatively, HHV-8 may be a "passenger" in KS.

Engineering human glycoprotein hormone superactive analogues

We report the generation of superactive analogues of human glycoprotein hormones, with potential applications in thyroid and reproductive disorders. Current biological and structural data were used to rationalize mutagenesis. The 11-20 region in the alpha-subunit with a cluster of lysine residues forms a previously unrecognized domain critical for receptor binding and signal transduction, as well as an important motif in the evolution of glycoprotein hormone activities. The gradual elimination of basic residues in the alpha-subunit coincided with the evolutionary divergence of the hominids from the Old World monkeys. By selective reconstitution of certain critical residues present in homologous nonhuman hormones we have developed human thyroid stimulating hormone and chorionic gonadotropin analogues with substantial increases in receptor binding affinity and bioactivity, thus providing a paradigm for the design of novel therapeutic protein analogues.

The epidemiology of AIDS--related neoplasms

The magnitude for and risk factors of the two most important AIDS neoplasm, Kaposi's sarcoma and non-Hodgkin's lymphoma, are reviewed in detail. The association between AIDS and other cancers is mostly speculative because surveillance biases tend to favor detecting associations that may be spurious. The overall relative risk of other cancers appears, however, to be only twofold above that in the general population, with associations being most convincing for anal (but not cervical) cancer and leiomyosarcoma and possible also for Hodgkin's disease, testicular cancer, and conjunctival cancers.

Endocrine implications of human immunodeficiency virus infection

Endocrine abnormalities occur frequently in HIV-infected patients. Although the majority of endocrine disorders reflect chronic infection, stress, and malnutrition, some disorders are characteristic of HIV infection or AIDS and deserve particular clinical attention. Identification of HIV patients at risk of frank endocrine disorders, rapid and correct diagnosis, and appropriate management are essential steps to minimize morbidity and mortality. Finally, increasing evidence from in vitro studies suggests that various hormones may influence HIV replication as well as the course of HIV disease and associated disorders. Future studies on the molecular mechanisms of hormones on HIV action and clinical studies on the effects of hormones as adjunctives to established forms of therapy may stimulate development of novel therapeutic strategies that will benefit HIV-infected patients.

HIV infection and neoplasia

HIV infection predisposes to several neoplastic conditions, especially non-Hodgkin lymphoma (NHL) and Kaposi's sarcoma (KS), and also intraepithelial cervical neoplasia (CIN) and anal neoplasia (AIN) (but not cervical or anal invasive cancer) and possibly seminoma. For neoplasias associated with oncogenic human viruses (ie, some NHL, CIN, AIN, and probably KS) the role of HIV is most probably linked to its immunosuppressive effect and interference with immune-mediated tumour surveillance. HIV-1, through its regulatory protein tat, might also have a direct promoting effect on KS lesions but it is not essential for their development. The increased frequency of Burkitt's lymphoma and Epstein-Barr-virus-negative large-cell lymphoma in AIDS patients, but not in immunosuppressed transplant patients, and the increased rate of testicular tumours in HIV-infected individuals remain unexplained and may indicate either a direct role for HIV or other cofactors.

Human chorionic gonadotropin hormone is antiviral

Although it is well known that human chorionic gonadotropin maintains the corpus luteum's ability to secrete estrogen and progesterone, I believe that it serves yet another important function. Early evidence suggests that human chorionic gonadotropin is a broad-spectrum antiviral/immune potentiator.

Latent BK virus infection and Kaposi's sarcoma pathogenesis

We have analyzed by PCR skin lesions from classic, endemic and AIDS-related Kaposi's sarcoma (KS), as well as from KS-derived cell lines, the presence of ubiquitous transforming viruses. BK virus (BKV), a transforming human papovavirus which has been associated with human tumors, was detected in 100% of KS skin lesions and 75% of KS cell lines. KS specimens contained a full-length, intact BKV early region, but minor rearrangements were observed in some tumors. BKV was also detected with a high prevalence (57-67%) in genital tissues and sperm, thus fulfilling the role of a sexually transmitted agent in KS. The closely related JC virus (JCV), which has never been associated with human malignancies, was present in 11-20% of KS specimens and was detected with a low prevalence (0-21%) in genital tissues and sperm. Simian virus 40 (SV40) was not detected in any KS lesions. Herpes simplex virus (HSV) DNA sequences were detected in 20-25% of KS lesions. Malignant human papillomavirus (HPV) types 16 and 18 and benign HPV types 6 and 11 were detected in KS specimens with a similar prevalence of 11-83%, suggesting that the presence of HPV-transforming sequences is not a specific trait of HPV interaction with KS tissue. Furthermore, JCV, SV40, HSV and HPV DNA sequences were not detected in KS cell lines, suggesting that these viruses are not associated to KS neoplastic cells in KS tissue. KS cell lines were also negative for DNA sequences of KS-HV, the novel herpesvirus detected in primary KS lesions. The constant association of BKV DNA with KS lesions and KS cell lines suggests that BKV-transforming functions may participate in the development of KS.

Apoptosis--molecular mechanisms and biomedical implications

Apoptosis is a distinct form of cell death of importance in tissue development and homeostasis and in several diseases. This review summarizes current knowledge about the regulation and molecular mechanisms of apoptosis and discusses the potential role of disregulated apoptosis in several major diseases. Finally, we speculate that modulation of apoptosis may be a target in future drug therapy.

Over-expression of hepatocyte growth factor in human Kaposi's sarcoma

Kaposi's sarcoma is a highly vascularized multifocal tumor which frequently appears as a complication of HIV infection. It has been suggested that a disorder in the cytokine network may contribute to the development of the disease. We examined the expression of several cytokines in human sporadic Kaposi's-sarcoma specimens, as well as in spindle cells cultured from human lesions, and consistently found high levels of expression of hepatocyte growth factor (HGF). In addition, human lesion-derived spindle cells synthesize and secrete biologically active hepatocyte growth factor and express the hepatocyte-growth-factor receptor (c-MET). Moreover, elevated levels of transforming growth factor beta 1 (TGF beta 1) mRNA were found in lesions of human sporadic Kaposi's sarcoma and in lesion-derived spindle cells which also over-express urokinase. Since HGF, TGF beta 1 and urokinase are all involved in capillary-vessel organization, dysregulation of these interacting agents may play a role in the initiation and/or progression of Kaposi's sarcoma, stimulating the growth of spindle cells and recruiting endothelial cells into the lesion.

Kaposi's sarcoma-associated herpesvirus infects endothelial and spindle cells

Kaposi's sarcoma (KS), a vascular tumour that contains characteristic spindle cells forming slit-like spaces, may have an infectious aetiology. Recently, sequences of a new human herpesvirus, KSHV/HHV-8, have been identified in both HIV-associated and classical KS. We sought to identify the target cell of this virus in KS tumour tissue. Using PCR in situ hybridization (PCR-ISH) we show that KSHV/HHV-8 is present in the flat endothelial cells lining vascular spaces of KS lesions as well as in typical KS spindle cells. These findings show that KSHV/HHV-8 is present in the cell types thought to represent neoplastic cells in these lesions.

Systemic gene therapy: biodistribution and long-term expression of a transgene in mice

We have investigated the in vivo efficacy of a systemic gene transfer method, which combines a liposomal delivery system (DLS liposomes) with episomally replicative DNA plasmids to effect long-term expression of a transgene in cells. A single i.v. injection of a plasmid DNA vector containing the luciferase gene as a marker was administered with the DLS liposomes in BALB/c mice. The luciferase gene and its product were found in all mouse tissues tested as determined by PCR analysis and immunohistochemistry. Luciferase activity was also detected in all tissues tested and was present in lung, liver, spleen, and heart up to 3 months postinjection. In contrast to the nonepisomal vectors tested (pRSV-luc and pCMVintlux), human papovavirus (BKV)-derived episomal vectors showed long-term transgene expression. We found that these episomal vectors replicated extrachromosomally in lung 2 weeks postinjection. Results indicated that transgene expression in specific tissues depended on the promoter element used, DNA/liposome formulation, dose of DNA per injection, and route of administration.

Human retroviruses in the second decade: a personal perspective

Human retroviruses have developed novel strategies for their propagation and survival. A consequence of their success has been the induction of an extraordinarily diverse set of human diseases, including AIDS, cancers and neurological and inflammatory disorders. Early research focused on their characterization, linkage to these diseases, and the mechanisms involved. Research should now aim at the eradication of human retroviruses and on treatment of infected people.