Gene expression profiling of Nm23-H2 overexpressing CAL 27 cells using DNA microarray

Nm23-H1/NDPKA and Nm23-H2/NDPKB belong to a large family of NDP kinases, group of structurally and functionally closely related enzymes. The Nm23/NDPs are known to catalyse the transfer of terminal phosphates from ATP to other NTPs and dNTPs. Besides their role in the maintenance of the cells NTP pool the nm23 genes/proteins are known to have additional different biological functions, the most important being its metastasis suppressor activity. The complete picture of roles, actions and targets of nm23 genes/proteins is yet to be discovered. Our goal was to identify the downstream targets of Nm23-H2 by subjecting Nm23-H2 overexpressing CAL 27 cells (oral squamous cell carcinoma of the tongue) to microarray analysis. Using this powerful technology we identified genes, groups of genes and signalling pathways that could be clustered into several groups: apoptosis related genes, cell cycle and DNA damage, TGFbeta (transforming growth factor beta) signalling pathway and related molecules, WNT signalling pathway, differentiation and epithelial structural and related molecules, cell adhesion, metalloproteinases and their inhibitors, vesicular transport related molecules, proteasome associated, ubiquitin mediated proteolysis and several metabolic pathways. Based on these results we suggest that nm23-H2 might have an important role in oral squamous cell carcinoma which is to be confirmed by future studies.

Novel alleles of the D16S752 polymorphic genetic marker linked to E-cadherin gene--a potential population marker

Seven DNA variants that polymorphic genetic marker D16S752 reveals in Croatian population are reported in this paper. The marker is a GATA tetranucleotide repeat linked to human E-cadherin gene (CDH1). Prior studies involving this marker revealed only four DNA allele variants. The reported DNA variants contribute to the collection of hypervariable DNA polymorphisms data useful in the field of anthropological and population genetic and forensic medicine.

Natural zeolite clinoptilolite: new adjuvant in anticancer therapy

Natural silicate materials, including zeolite clinoptilolite, have been shown to exhibit diverse biological activities and have been used successfully as a vaccine adjuvant and for the treatment of diarrhea. We report a novel use of finely ground clinoptilolite as a potential adjuvant in anticancer therapy. Clinoptilolite treatment of mice and dogs suffering from a variety of tumor types led to improvement in the overall health status, prolongation of life-span, and decrease in tumors size. Local application of clinoptilolite to skin cancers of dogs effectively reduced tumor formation and growth. In addition, toxicology studies on mice and rats demonstrated that the treatment does not have negative effects. In vitro tissue culture studies showed that finely ground clinoptilolite inhibits protein kinase B (c-Akt), induces expression of p21WAF1/CIP1 and p27KIP1 tumor suppressor proteins, and blocks cell growth in several cancer cell lines. These data indicate that clinoptilolite treatment might affect cancer growth by attenuating survival signals and inducing tumor suppressor genes in treated cells.

The efficacy of retroviral herpes simplex virus thymidine kinase gene transfer and ganciclovir treatment on the inhibition of melanoma growth in vitro and in vivo

One approach to gene therapy of cancer is based on the insertion of a suicide gene into tumor cells and subsequent activation of the suicide mechanism. We used the herpes simplex virus thymidine kinase (HSVtk) gene followed by ganciclovir (GCV) treatment. The goal of our experiments was to determine the effectiveness of HSVtk gene therapy in malignant melanoma. B16BL6 murine melanoma cells retrovirally transduced with the HSVtk gene became sensitive to low concentrations of GCV. Analysis by RT-PCR showed HSVtk expression in transduced B16BL6tk+ cells. Apoptotic cell death was found in B16BL6tk+ cells treated with GCV (20 microM). The sensitivity of B16BL6tk+ cells to GCV was also examined in vivo. Tumors inoculated subcutaneously into C57BL6 mice regressed rapidly when treated with GCV (50 mg/kg twice a day) and disappeared completely after 14 days treatment. The mice remained in remission for 5 months. A bystander effect through which nontransduced B16BL6 cells were also inhibited by GCV administration when cocultured with B16BL6tk+ cells was expected. However, only slight killing of nontransduced cells was observed in vitro. Analysis of the bystander effect in vivo showed complete regression of tumors inoculated with a mixture of cells mostly consisting of B16BL6tk+ cells. A distant bystander effect was also examined. There was no regression of wild-type tumors raised at a distant site from primary B16BL6tk+ tumors. The failure of a more effective bystander effect indicates the need for further investigation of the possible use of combined gene therapy to treat melanoma.

Helicobacter pylori colonization of tongue mucosa--increased incidence in atrophic glossitis and burning mouth syndrome (BMS)

Nested polymerase chain reaction (PCR) was performed to detect the presence of Helicobacter pylori in tongue mucosa in 268 patients divided into four groups according to their diagnosis: 87 with atrophic glossitis, 37 with benign migratory glossitis and 144 with burning mouth syndrome (BMS). The latter group was subdivided according to anatomic site of burning sensation: subgroup A (54 patients) with complaints limited to tongue and subgroup B (90 patients) with burning sensations in other parts of oral mucosa. H. pylori was found in 43 samples (16%). Bacteria were significantly less present in tongue mucosa affected with benign migratory glossitis compared with atrophic glossitis and BMS (P=0.025). This difference was more obvious when compared with atrophic glossitis only (P=0.006). Mucosal changes in these conditions might make the oral environment more acceptable for H. pylori colonization compared with normal mucosa, and this mechanism may play a role in its oro-oral transmission.

The expression and role of insulin-like growth factor II in malignant hemangiopericytomas

Hemangiopericytoma is a rare soft tissue tumor originating from contractile pericapillary pericytes. To address the issue of molecular genetic events that participate in genesis and progression of hemangiopericytoma we analyzed insulin-like growth factor (IGF) II and IGF I receptor in 29 tumors collected from a human tumor bank network. Seven of these tumors were associated with severe hypoglycemia; six were retroperitoneal and one was located in the leg. Of 22 tumors tested 12 (54.5%) exhibited IGF II mRNA, while almost 90% (17 of 19) of hemangiopericytomas exhibited IGF I receptor mRNA. Sera from some patients whose tumors expressed IGF II mRNA contained elevated levels of IGF II. Removal of the tumor eliminated most of the IGF II immunoreactivity from the sera. The potential role of IGF II as a growth-promoting factor was examined on three malignant primary hemangiopericytoma cell cultures. Extracellular addition of IGF II significantly enhanced cell proliferation in a dose-dependent manner. Antisense oligodeoxynucleotides that specifically inhibit IGF II mRNA, at a concentration of 40 or 80 micrograms/ml, inhibited the growth of hemangiopericytoma cells significantly, by 40%. Simultaneous administration of antisense deoxyoligonucleotides to both IGF II and IGF I receptor inhibited tumor cell proliferation by even 80%. Our data suggest that tumor cells produce IGF II, and that this in turn stimulates their proliferation by autocrine mechanisms.

Loss of heterozygosity and protein expression of APC gene in renal cell carcinomas

This study evaluated the potential contribution of the APC gene to malignant transformation in patients with renal cell carcinoma. We tested 36 human renal cell carcinoma samples and 18 adjacent normal kidney tissues for the expression of APC protein, both wild and truncated types, by western blot using antibodies that recognize either the carboxy or the amino epitope of the APC protein. The same tumor samples together with autologous peripheral blood were also analyzed at the DNA level. Using specific oligonucleotide primers for exons 11 and 15, gene instability was followed by polymerase chain reaction/loss of heterozygosity (LOH) (on the basis of restriction fragment length polymorphism). Molecular data were also compared to pathohistological diagnosis, TNM stage, and patient's age using multivariate statistical methods. All normal renal tissues revealed expression of the wild-type APC protein. Neither wild nor mutant type proteins were found in 36% (13/36) of tumor samples; the rest of tumor tissues expressed the wild-type protein (312 kDa). Mutated APC protein, with a molecular weight of 117 kDa, was found in only one tumor sample. From 36 tumor samples 16 (44.4%) were informative for RsaI exon 11 polymorphic site, while only half of these (8/16) demonstrated LOH. From 13 tumor samples that had no detectable protein product by western blot analysis eight were homozygous for the exon 11 polymorphism and were tested for another polymorphic site, MspI/exon 15. The overall proportion of LOH cases for both polymorphisms tested was 52.9% (9/17). Pathohistological diagnosis and molecular data showed no correlation. However, multivariate analysis determined a stage strong positive correlation of age and TNM with the presence of LOH and the absence of the wild-type APC protein. Out results suggest that the APC tumor suppressor gene plays a role in renal carcinogenesis. Alterations in this gene are responsible for tumor evolution and progression, but cannot be considered as a first event in tumor initiation.

Molecular pathology of hemangiopericytomas accompanied by severe hypoglycemia: oncogenes, tumor-suppressor genes and the insulin-like growth factor family

Relatively little is known about molecular genetic events that participate in the genesis and progression of hemangiopericytoma. In this study, we describe two cases of hemangiopericytoma accompanied by severe hypoglycemia. Tumor cells from patient 1 exhibited insulin-growth factor I (IGF I) and insulin-like growth factor I receptor (IGF IR) mRNA transcripts. Tumor cells from patient 2 exhibited IGF II, IGF IR and IGF binding proteins 1-3 mRNA. Serum from patient 2 contained IGF II, mostly in a large molecular form ("big" IGF II); the IGF II level did not change after the tumor removal. The presence of IGF IR in tumor cells was confirmed by immunoprecipitation with antibodies that recognize human IGF IR subunit (visualized as a 460-kDa band). The hemangiopericytoma cells derived from patient 1 expressed 210000 IGF I receptors/cell. Specific binding of IGF I to the tumor cell membrane fraction was higher in tissue from patient 1, while the tissue of patient 2 showed relatively low IGF I binding. In contrast, IGF II binding was much higher in tissue from patient 2. Both tumor tissues showed positive immunostaining for c-Jun; one tumor showed strong immunostaining for c-Myc, H-Ras and p53, while the other exhibited strong reaction with H-Ras antibodies only. No loss of the heterozygosity at the genes APC, NFI and nm23-H1 loci in tumor tissue obtained from patient 1 was found. In effect, our results suggest multiple molecular genetic changes in hemangiopericytoma -- activation of some oncogenes and the IGF growth factor family. IGF ligands together with IGF IR could be responsible for hypoglycemia and perhaps the transformed phenotype.

Detection of Helicobacter pylori in various oral lesions by nested polymerase chain reaction (PCR)

Nested PCR was used for the detection of Helicobacter pylori DNA in specimens collected from seven different topographic sites in the oral cavity. Out of 161 patients, only 21 (13.04%) were positive. There was no correlation between H. pylori status and patient diagnosis and age. No preferential site for bacterial colonization was found in the oral cavity, nor was an association established between a bacterial presence and ulcerated versus non-ulcerated lesions. The results indicate that the oral mucosa does not appear to represent a preferred site of colonization for H. pylori. Furthermore, the evidence presented in this paper suggests that H. pylori is not pathogenic in the oral cavity, nor is it associated with common oral pathologic processes.

Squamous cell lung carcinomas: the role of nm23-H1 gene

This analysis of 32 pairs of human squamous cell lung carcinomas and normal matched control DNA demonstrates that loss of heterozygosity (LOH) is infrequent at the nm23-H1 locus, affecting only 2 of the 18 informative cases. Both LOH cases were in the tumor stage IIIA. One tumor was of poor and the other of moderate histological grade. These and an additional 34 tumor samples were also analyzed immunohistochemically for the presence of nm23-H1 protein. Of the 66 cases tested for the presence of nm23-H1 protein 54 were negative. Eight samples exhibited up to 35% positive cells (with weak immunostaining intensity) and four between 35% and 70% (moderate immunostaining intensity); no sample showed more than 70% positive cells. Noncancerous lung parts contained no nm23-H1 protein. nm23-H1 expression was independent of TNM stage, grade, tumor size, and patient's survival. Two samples with LOH were negative for nm23-H1 protein. We therefore conclude that neither loss of heterozygosity of the nm23-H1 gene nor the intensity of specific protein expression are related to squamous cell lung carcinoma development and progression.

4,9-diazapyrenium dications induce apoptosis in human tumor cells

We investigated the antiproliferative effects of two planar 4,9-diazapyrenium hydrogenasulphates against human malignant MiaPaCa 2 (pancreatic carcinoma), Hep 2 (laryngeal carcinoma) and human normal fibroblasts (WI 38) cell lines. The tested compounds were very potent in inhibiting the growth of the treated cell lines. Treatment with molar concentrations of the substances (10(-4)-10(-7) M) caused growth inhibition by more than 50%. The morphological changes of treated cells were also observed. Cells became smaller, with condensed chromatin and fragmented nuclei, the characteristics of dying cells. The identification of DNA-fragmentation and the appearance of chromatin aggregation leads us to assume the tested substances induced apoptosis of the investigated tumor cell lines.

Concomitant point mutation of tumor suppressor gene p53 and oncogene c-N-ras in malignant neuroendocrine pancreatic tumor

Activation by point mutation of ras family genes as well as point mutations of the p53 tumor suppressor gene are found in many tumors. Here we describe a rare case of malignant neuroendocrine pancreatic tumor with multiple metastases in different organs showing strong positivity for synaptophysin, glucagon-like peptide 1, pan-cytokeratin, moderate positivity for chromogranin, Phe-5 and calcitonin and weak positivity for vasointestinal peptide. We found a point mutation at codon 61 of the c-N-ras oncogene, and point mutations in the p53 tumor suppressor gene in the primary tumor as well as in its metastases in liver. The mutation in the c-N-ras gene was a cytosine to adenine transversion, resulting in the amino-acid lysine. Allele specific hybridization showed that the mutation involved one of two c-N-ras alleles as the oligonucleotide for the normal codon also hybridized to amplified tumor DNA. Concomitant mutation of the p53 tumor suppressor gene at codons 248 and 249 was found. The mutation in codon 248 was a cytosine to guanine transversion resulting in the amino-acid glycine. The mutation in codon 249 was a third base, G- > T, transversion leading to a change from arginine to serine. This is the first time that concomitant point mutations in c-N-ras and p53 have been found in a neuroendocrine pancreatic tumor. Based upon these and our previous results, we concluded that these genetic changes may play a role in the development of this particular pancreatic tumor.

Nested polymerase chain reaction for detection of hepatitis C virus RNA in blood derivatives

Testing for the presence of hepatitis C virus (HCV) in blood derivatives used in clinical medicine is of enormous importance to ensure the production of safe preparations. So far, no system has been developed for the isolation and detection of hepatitis C virus from blood derivatives. The recently introduced commercial kit for the detection of hepatitis C virus is designed for the isolation and detection of virus from blood serum. A reliable and reproducible method for the isolation of hepatitis C virus RNA, subsequent reverse transcription and nested polymerase chain reaction (PCR) from blood derivatives is described. Of 17 batches of factor VIII, gamma-globulin and anti tetanus, cytomegalovirus and Varicella-zoster immunoglobulin concentrates, respectively (14 negative for anti HCV and 3 of unknown anti HCV status) five were found positive in RNA-PCR.

p53 immunoreactivity in oligodendrogliomas

Data are presented on p53 protein presence in human oligodendrogliomas whose progress from low grade to anaplastic oligodendroglioma can be followed. Expression was evaluated by formalin-fixed paraffin-embedded section immunohistochemistry, using monoclonal PAb 1801 antibody. The frequency of p53 protein accumulation is related to the stage of tumor malignancy. All the samples (100%) of malignant oligodendrogliomas were positive for p53 protein. Of 14 type II oligodendroglioma samples, 9 were positive (64%) while among type I oligodendroglioma the positivity was 28%. The mean proportion of reactive cells was also higher in malignant oligodendrogliomas. However, mean intensity staining did not differ among various grades of tumors. Our results point to the direct link between p53 protein accumulation and the malignant stage of human oligodendrogliomas. However, the value of p53 protein accumulation in predicting malignant behavior of oligodendrogliomas requires further confirmation.

DNA amplification by polymerase chain reaction from brain tissues embedded in paraffin

A method which enables analysis of DNA from archival paraffin embedded normal and malignant brain tissue is described. The demonstration of a 317-bp long beta-actin DNA sequence by the polymerase chain reaction (PCR) was used to identify which fixation procedure, deparaffinization time and DNA extraction procedure would give the best results. Tissue specimens 1-39 years old were included in the experiments. Specimens fixed in either 10% formalin, Carnoy's or AMeX fixative were found to be best suited for subsequent analysis by PCR. Paraformaldehyde and acetone compromised amplification efficiency, while Bouin's fixed tissue gave uniformly negative results. Regardless of fixative used, PCR reaction had to be run through at least 40 cycles. Prolonged deparaffinization time and phenol/chloroform extraction of DNA did not influence DNA quality as a template for PCR reaction. Formalin fixed brain tumours can be successfully used for DNA/PCR analysis even if they are up to 39 years old.

PCR amplification of DNA from stained cytological smears

DNA from archival Papanicolaou stained smears was successfully amplified using the polymerase chain reaction (PCR) to see if it could be used for retrospective genome studies such as detection of the presence of human papilloma virus (HPV) and changes in p53 gene expression. DNA was isolated and purified by treatment with proteinase K, phenol/chloroform, and isoamyl alcohol. Segments of the human beta actin and TGF beta 1 gene were amplified by PCR. Of all stains used in the preparation of Papanicolaou smears, only eosin was detectable as a greenish band in ethidium bromide treated DNA gels under ultraviolet illumination.

c-fms is present in primary tumours as well as in their metastases in bone marrow

The expression of c-fms oncoprotein in different primary tumours as well as in their metastases in bone marrow, was shown. All the samples were fixed and processed by the acetone, methyl benzoate, xylene procedure (AMeX), which was suitable for studying oncoprotein expression not only in primary tumours but also in bone marrow (BM) biopsies. Among the patients suffering from acute myeloid leukaemia (AMeL), positive c-fms cells were found in 55% cases. On the contrary, patients with lymphocytic cell disorders have not had detectable c-fms oncogene product in BM biopsies.c-fms oncoprotein was also detected in some primary tumour specimens (lung carcinoma, cervical carcinoma, gastric carcinoma, breast carcinoma and melanoma) and their metastases in BM, while it was not present in normal uterine tissue. There was a positive correlation between c-fms oncoprotein expression in primary and metastatic tumours. Our results showed that c-fms product is confined, not only to some normal, but also to the variety of malignant cells of different origin.

The role of insulin-related substance in Hodgkin's disease

An insulin-related growth-promoting substance was detected in the serum of a patient with Hodgkin's disease who suffered from severe hypoglycaemia, as well as in the supernatant of homogenized spleen tissue of the same patient. Low concentrations of this substance enhanced DNA synthesis of short-term-cultured spleen tumour cells obtained from the same patient, while the addition of anti-insulin antiserum interfered with that effect. Moreover, the preincubation of this insulin-related substance with the anti-insulin antiserum abrogated its stimulatory effect on tumour cell proliferation. Both insulin and the insulin-related substance bound to patients splenocytes to a similar extent. The data suggest that the insulin-related substance, found in this particular case of Hodgkin's disease, plays a role in tumour progression by an autocrine mechanism.

Presence of oestrogen receptors on target cells and antiproliferative activity of estramustine phosphate: positive correlation for human tumours in vitro

Incubation with estramustine phosphate for 24 h inhibited DNA, RNA and protein synthesis in primary cultures of human kidney, mammary, prostatic, cervical and endometrial carcinoma. Not only the presence, but also the concentration of oestrogen receptors correlated with estramustine phosphate effects on tumour cell proliferation.

[The structure and mechanism of action of insulin receptors]

The insulin receptor is an integral part of plasma membrane of most cells. It consists of 2 alpha and two beta subunits. The alpha subunit is the hormone binding component, while beta subunits are a tyrosine specific protein kinase which itself can be autophosphorylated. Receptor tyrosine kinase activation upon insulin binding catalyses the phosphorylation of exogenous substrates and endogenous cellular proteins. It is reasonable to think that the insulin induced autophosphorylation, activation of its receptor kinase and changes in intracellular substrates represent important events in the action of insulin on cell metabolism and growth.

Growth factors in human tumors

Various human tumor tissues contain different growth factors. In some cases progression of tumors is paralleled by elevated levels of these substances in blood or in tumor tissue. There is evidence that these growth promoting peptides might stimulate tumor growth. The growth of most tumors was associated with insulin-like substances (MW 45,000). We isolated and purified a substance immunologically cross-reactive with insulin (SICRI) from human melanoma. We found the molecular weight of affinity purified SICRI to be approximately 120,000. Our in vitro experiments with human renal carcinoma cells and growth factors suggest an important role of these molecules in tumor progression.

In vivo effect of progesteron and estrogen on thymus mass and T-cell functions in female mice

Progesteron and estradiol, administered in doses equivalent to those used for therapy caused a marked transient reduction of the thymus mass, but did not affect the cellularity of other lymphoid organs. Humoral and cellular immune response of the hormone-treated mice was normal at the time of thymus involution. The same was true for the stem-cell differentiation capacity. The remaining thymus cells after hormone treatment showed increased DNA-synthesis.

Murine myeloid leukemia: in vivo suppression by sericystatin A, a proteinase inhibitor from leukocytes

Parenteral administration of sericystatin A, an intracellular leukocyte inhibitor of the proinsulin-splitting enzyme cathepsin B, prolongs the mean survival time of mice with insulin-dependent myeloid leukemia. Sericystatin A reduces the supranormal blood levels of substances detectable by insulin-specific radioimmunoassay in these animals; this effect is abolished by concomitant insulin administration. It is concluded that sericystatin A reduces tumor proliferation indirectly, i.e. by reducing circulating insulin levels.

Carcinomas of the cervix and corpus uteri in humans: stage-dependent blood levels of substance(s) immunologically cross-reactive with insulin

Inasmuch as the elevated levels of substance(s) immunologically cross-reactive with insulin (SICRI) in a diabetic woman with carcinoma of the corpus uteri decreased following the surgical removal of the uterus and ovaries, 80 women with cervical carcinomas of various stages and 70 women with carcinomas of the corpus uteri of various stages were screened for the levels of SICRI and C-peptide. The levels of SICRI in the second, third, and fourth stages of the cancers were elevated (up to six times above the normal levels of immunoreactive insulin) and stage-dependent. The levels of C-peptide, which are related to the insulin-secreting activity of pancreatic beta-cells, were normal and independent of the stage of cancer.

Different endocrinological properties, growth rate and sensitivity to chemotherapy of aplastic mammary carcinoma in normo- and hypoglycemic phase of tumor growth

An aplastic mammary carcinoma (AMC) grew slower in hypoglycemic mice (caused by fasting or by daily insulin injections) and in hyperglycemic mice (caused by alloxan or streptozotocin, or by daily injections of glucose) than in normoglycemic mice. The tumor was able to adapt to the unfavourable conditions of the diabetes; cells, when transplanted from diabetic donors into diabetic recipients, secreted immunoreactive insulin (IRI) and immunoreactive glucagon (IRG), which are deficient in the diabetic hosts. In the terminal (hypoglycemic) phase of tumor growth, the concentrations of glucose, IRI and IRG decreased. The immunological reactivity of the host animals was reduced in the hypoglycemic terminal phase. The tumor cells taken from hosts in this phase behaved differently from the cells taken in the normoglycemic phase. The "hypoglycemic" cells grew more slowly in healthy mice; the intensity of their DNA synthesis was diminished, their response to antitumor therapy was weaker. Furthermore, it was necessary to transplant more of these cells to obtain tumors in all recipients, and they lost their ability to adapt to diabetic conditions (i.e. secreted neither IRI nor IRG). Hypoglycemia was apparently the immediate cause of death in mice with AMC. Injections of glucose or glucagon into mice with AMC eliminated the hypoglycemia temporarily and postponed the death by 4 days. Mice treated with glucagon and with chemotherapy or immunotherapy survived 6-9 days longer than mice treated with chemo- or immunotherapy alone. Some of these differences between the end-stage and the progressively growing tumors could be explained in terms of tumor cell kinetics but some could be attributed to metabolic conditions of the host caused in part by the tumor.

Somatostatin suppresses growth of murine myeloid leukemia in vivo

Daily injections of somatostatin into mice with myeloid leukemia retarded the tumor growth. This myeloid leukemia is an insulin-dependent tumor (in that it grows more slowly in hypoinsulinemic diabetic mice than in nondiabetic animals). Since somatostatin decreased the level of immunoreactive insulin in mice with myeloid leukemia, and since the treatment with insulin abrogated the antileukemic effect of somatostatin, we attribute retarded growth of this leukemia to decreased secretion of insulin, caused by somatostatin.

Habituation of a mammary aplastic carcinoma on diabetic conditions

Hypoglycemia and hypoinsulinemia accompanied the i.m. growth of mammary aplastic carcinoma in CBA mice. In hosts rendered diabetic by means of alloxan, the tumor decreased blood glucose levels to almost the level seen in non-diabetic mice. Tumors maintained in diabetic mice grew faster after each subsequent transplantation into diabetic mice, and we noted increased incorporation of 3H-thymidine into DNA of these tumor cells. The observed proliferation enhancement of mammary aplastic carcinoma maintained in diabetic mice is caused by de novo insulin and glucagon synthesis, apparently by the tumor cells themselves.

Growth and treatment of B 16 melanoma in hyperglycemic mice

Melanoma B-16 grew slowly in mice with hyperglycemia induced by alloxan, glucagon, or glucose. The mechanism of retarded tumor growth is different and depends on the origin of hyperglycemia. The concentration of immunoreactive insulin in blood of mice with melanoma and in the tumor tissue is increased in nondiabetic as well as in diabetic mice. The chemotherapy of melanoma in diabetic mice is as effective as in nondiabetic mice whereas immunotherapy in diabetic mice is not effective. Combined chemoimmunotherapy of melanoma in diabetic mice is more effective than either therapy alone only when mice are given a daily dose of insulin.

Glucagon suppressed proliferation rate of mammary aplastic carcinoma in mice

Glucagon injected into mice with mammary aplastic carcinoma retards the growth and prolongs the mean survival time of the animals. Glucagon stimulates the plaque-forming capacity and phagocytosis in tumor-bearing animals. Cyclophosphamide treatment abolishes the antitumor effect of glucagon, while the effect of the hormone is enhanced in Corynebacterium parvum pretreated animals. It follows that the tumor-retarding effect of glucagon are mediated by mainly by maintaining high B-type reactivity and phagocytosis.

Growth and treatment of Ehrlich tumor in mice with alloxan-induced diabetes

Hypoglycemia and hypoinsulinemia accompanied i.p. or i.m. growth of the Ehrlich tumor in CBA/H and BALB/c mice. Simultaneously, insulin accumulated in the ascitic fluid of tumor-bearing mice. In hosts rendered diabetic by means of alloxan, the tumor decreased the blood glucose almost to the level seen in nondiabetic mice. Tumor growth was retarded in diabetic hosts, but cells from such tumors, transplanted into secondary diabetic recipients, grew faster than in their primary diabetic hosts, similarly to "nondiabetic" tumor cells growing in nondiabetic hosts. This phenomenon of "adaptation" of the tumor to the diabetic state was prevented if diabetic tumor-bearing mice were daily treated with insulin. The tumor did not grow in all diabetic recipients; the frequency of takes correlated with severity of the diabetes, i.e., with the dose of alloxan given to induce it. The greater the dose, the less mice accepted the tumor. Insulin injection into diabetic tumor-bearing mice promoted the tumor growth. Simultaneous treatment of diabetes and the tumor afforded the best antitumor effect.

Recovery of immune system in diabetic mice after treatment with insulin

In mice with alloxan-induced diabetes, humoral and cellular immunological reactivity were weak. The number of leucocytes, and especially lymphocytes, was reduced, and the weight and cellularity of lymphatic organs were lower than in normal mice. Treatment of diabetic mice with insulin reversed morphological and functional deficiency of the immunological system. Observed depression of immunological functions was attributed to impaired transport of glucose into immunocompetent cells, rather than to toxic effects of alloxan.