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Biomedical subjects

V P Hollander

Publications and source records attributed to V P Hollander.

At least 19 recordsLinked to original sources
PubMed1992

Differential effects of LHRH and somatostatin analogs on human breast cancer.

We have been interested in the possible direct effects of luteinizing hormone releasing hormone (LHRH) and somatostatin (SS) analogs on the growth of human mammary tumor cells. Four recently synthesized peptide hormones including the LHRH agonists D-Trp6-LHRH and zoladex, LHRH antagonists SB30 and SB75, and the somatostatin analog RC 160 were analyzed for their effects on DNA synthesis of MCF-7 breast cancer cells in culture. At 48 hr, D-Trp6-LHRH and SB30 did not show significant effects (dose range, 10(-12)-10(-6) M). However, the combination of these two peptides at 10(-10) M produced significant inhibition of 3[H]thymidine incorporation (50% control). At 72 hr in the absence of estradiol-stimulated growth, D-Trp6-LHRH showed inhibition at 10(-12) and 10(-10) M (P less than 0.005 and 0.001). At higher concentrations, no significant inhibition was noted. In contrast to D-Trp6, SB30 (antagonist) showed no inhibition but significant stimulation of DNA synthesis at 10(-6) and 10(-4) M. In the presence of added estradiol (10(-9) M), complete reversal of D-Trp6-LHRH analog inhibition is noted. In contrast, there is persistent stimulation by SB30 (P less than 0.001). At 96 hr, D-Trp6-LHRH continued to show maximal inhibition of 70% in the absence of estradiol. SB30 stimulated DNA synthesis 100% at 10(-6) M. At 72 hr, the SS analog RC 160 demonstrated significant inhibition (53%) that was similar to D-Trp6 and SB75 peptides.(ABSTRACT TRUNCATED AT 250 WORDS)

Antineoplastic Agents↗
PubMed1992

The effect of dihydrotestosterone and culture conditions on proliferation of the human prostatic cancer cell line LNCaP.

Cell density, nutritional state, and serum factors modify the growth response of LNCaP human prostatic cancer cells to dihydrotestosterone. Evaluation of growth response to dihydrotestosterone requires logarithmic transformation of cell count or thymidine incorporation data. Under conditions of dose response, growth increases with cell density but no significant interaction of dihydrotestosterone with cell density was found under optimal culture conditions. The frequency of media change was a significant factor in modulating dose response. When cells from cultures maintained at different feeding periods were plated at different cell densities of (trypan blue) viable cells, significant effects of plating density on dihydrotestosterone response were found. Dihydrotestosterone protects cells under the adverse effects of media deprivation. Under the extreme adverse effects of serum deprivation, cells respond to dihydrotestosterone even under conditions of increasing cell loss. The effects of dihydrotestosterone on final cell density were significant. In the absence of serum, the elongated cells of LNCaP assume a round shape, but many remain adherent to the culture dish and can be restored to normal morphology by serum. A number of growth factors fail to restore normal morphology that was completely restored by a combination of fibronectin and dihydrotestosterone. We have not developed a practicable serum-free system for LNCaP.

Biological Factors↗
PubMed1992

Pituitary extract causes aggregation and differentiation of rat mammary tumor MTW9/Pl cells.

Alkaline pituitary extracts (PE) of the mammosomatotropic tumor MtTW10 differentiated cultured PRL-independent rat mammary tumor cells MTW9/Pl. Within 24 h, MTW9 cells growing in suspension began to aggregate and adhere to the plastic dish. Cultured dispersed MTW9 cells were undifferentiated, but PE treatment resulted in organoid aggregates that exhibited glandular luminal structures and periodic acid-Schiff-positive material consistent with basement membrane formation. Morphometric examination of organoids demonstrated a reduction in nuclear and cell perimeters compared to those of untreated cells. Electron microscopy showed that the treatment resulted in polarization, nuclear changes, junctional complexes, secretory spaces, microvilli, and basement membrane formation. A disaggregated undifferentiated tumor now appeared as a differentiated adenocarcinoma. PE induced expression of laminin and milk protein, but failed to increase fibronectin expression. Extracts of MTOM (a variant of MtTW10 which secretes little PRL) and bovine pituitary also produced aggregation and adhesion of MTW9. A number of tissue extracts, growth factors, and hormones failed to produce such aggregation. Laminin, but not fibronectin, produced aggregation and adhesion similar to those produced by PE. Cycloheximide inhibited the aggregation effect of PE, but not that of laminin. PE was mitogenic for MTW9, but inhibition of proliferation by vinblastine did not inhibit the aggregation induced by PE. These observations suggest that the pituitary contains a novel factor that stimulates matrix synthesis, resulting in differentiation, possibly laminin induced.

Animals↗
PubMed1991

Role of prolactin in growth of the rat mammary tumor MTW9.

The growth of MTW9 mammary tumors exhibits different degrees of responsiveness to ovariectomy, ranging from sensitivity to resistance. This range of response is a function of time elapsing from tumor inoculation until performance of ovariectomy provided that prolactin (PRL) level is kept continuously high. In vivo studies showed that the MTW9 tumors developed by chronic administration of spiramide were sensitive to ovariectomy by 60 days, but they became resistant to ovariectomy by 100 days. However, when spiramide treatment was discontinued after tumor appearance, the tumors were still sensitive to ovariectomy by 100 days. Chromatofocusing (CF) profile of cytosolic estrogen receptors (ER) correlated with the responsiveness to ovariectomy. A 2-peak profile for tumors sensitive to ovariectomy, and only a one-peak profile for tumors resistant to ovariectomy, were seen. Although the prolactin level in rats bearing the tumors was higher than in the normal rats, no correlation between the PRL level and the change in CF profile of ER over time was seen. Also, these changes could not be correlated with the tumor size. In vitro studies showed that incubation of cytosolic ER from a sensitive tumor (2 peaks) with PRL led to a CF profile with only one peak, characteristic of a resistant tumor. Leupeptin, molybdate and phenylmethylsulfonylfluoride (PMSF) could not prevent this transition. The effect was not reproduced by incubation with growth hormone or progesterone. Our data suggest that PRL, either directly or through intermediates, may play a role in changing the response to hormonal therapy of the mammary tumor MTW9.

Animals↗
PubMed1990

Serum of patients with prostatic cancer or benign prostatic hypertrophy contains nonpolar testosterone.

We have previously described a nonpolar form of radioimmunoassayable serum testosterone (NPT) not measured by available antitestosterone antibodies. It is detected by mild alkaline hydrolysis of the petroleum ether extract of serum and subsequent radioimmunoassay. The properties of NPT are consistent with that of a fatty acid ester of testosterone or dihydrotestosterone. The serum of young males contains 1 to 3 ng/ml NPT, but it is not detected in female serum. We measured serum testosterone and NPT levels in 36 men between 58 and 87 years of age. Seventeen subjects with advanced prostatic cancer (NPT 1.70 +/- 1.44 ng/ml) were compared with a control group consisting of six patients with benign prostatic hypertrophy (BPH) and 13 patients with no prostatic disease (NPT 0.72 +/- 0.46, P = 0.017). There was no significant difference between BPH patients and patients with no prostatic disease; the results were pooled. The concentration of NPT in prostatic cancer patients but not in controls was inversely correlated with that of testosterone. Immunoassayable testosterone was present in the serum of two orchiectomized patients and, therefore, cannot derive solely from the testes.

Aged↗
PubMed1989

Characterization by chromatofocusing of estrogen receptors from rat mammary tumor MTW9.

The estrogen receptor (ER) from rat mammary tumor MTW9-D, which is sensitive to ovariectomy, could be separated by chromatofocusing (CF) into two peaks specifically binding 3H-estradiol, focusing at pH 6.8 (peak A) and pH 6.0 (peak B). The ER from MTW9-MtT tumor, which is resistant to ovariectomy, presented only one peak, focusing at pH 6.0 (peak B). The peaks presented similar sedimentation coefficients (3.5s) with peak B being slightly larger than peak A. Regardless of the tumor sensitivity to hormonal manipulation, the two peaks presented similar molecular weights as shown by immunostaining of Western blots: a major duplex component of 70 kilodaltons (kd), and single bands at 48, 36, and 35 kd. The bands under 70 kd could be proteolytic products; however, the pattern could not be changed by addition of molybdate, leupeptin, or phenylmethylsulfonylfluoride. The pattern was reproducible in experiments done at different intervals of time or when rechromatofocusing. The peaks presented different isoelectric points: peak A, pH 6.8; peak B, pH 6.0. Also, they had different DNA binding abilities: peak A bound quantitatively to DNA, while peak B bound only 20%. Peak A was always present in tumors responsive to ovariectomy, a fact that suggests this ER component could be a marker for the responsiveness to hormonal therapy.

Animals↗
PubMed1989

Non-polar extracts of serum from males contain covert radioimmunoassayable testosterone.

Non-polar extracts of sera from human males contain immunoreactive testosterone in a form that is released by mild alkaline hydrolysis. The non-polar derivative shows no immunoreactivity with testosterone antibody prior to hydrolysis. Hydrolyzed non-polar serum extracts from ten adult male volunteers contained 2.0 +/- 0.8 (SD) ng/mL of testosterone. Neither non-polar serum extracts of normal females nor a water blank substituted for non-polar extract of serum yields any immunoreactive testosterone after alkaline hydrolysis. Testosterone palmitate hydrolyzed alone or after addition to non-polar extract of serum yields the expected quantities of radioimmunoassayable testosterone. Previously described conjugates of testosterone are polar and are neither extractable by petroleum ether nor hydrolyzable by alkali. These observations suggest that fatty acid esters of testosterone may be present in serum of human males.

Adult↗
PubMed1985

Lipopolysaccharide stimulation of plasmacytoma cells.

Various preparations of lipopolysaccharides (LPS) were tested for their effect on 6 plasma tumor cell lines. LPS from Escherichia coli B5:055, Salmonella minnesota 1114, and R7 mutant, as well as the glycolipid from S. minnesota 595 were highly stimulatory on cell suspensions from solid transplantable plasma tumor cells MOPC 315 and MPC11, as measured by thymidine incorporation and cell proliferation. Even nanogram doses were effective. LPS preparations from S. minnesota R5 and endotoxin-free cell wall residues of R5 and R7 mutants of S. minnesota had no stimulatory effect on these cells. In contrast, 4 lines of tissue culture-adapted plasma tumor cells (Adj PC5, HOPC-1, MOPC-21, and MPC11 TC) were not affected by any LPS preparation tested. Lymphosarcoma P1798 cells were also unaffected by these LPS.

Animals↗
PubMed1983

Interaction of ribonuclease A with estrogen receptor from rat mammary tumor MTW9.

Incubation of crude estrogen receptor preparations from mammary tumor cytosol with RNase A increases the sedimentation coefficient of the receptor from 9.7 S to 10.4 S. The effect is not obtained with other low molecular weight basic proteins (lysozyme, cytochrome c, or histone H2B). Nonenzymically active RNase A derivatives such as performic acid oxidized RNase A, fully reductively methylated RNase A, carboxymethyl-His-119-RNase A, and RNase S-protein were ineffective. RNase T1, an acidic endoribonuclease, was also without effect. However, enzymically active RNase S', prepared from a mixture of RNase S-protein and S-peptide, shifted the sedimentation to 10.4 S. The increased sedimentation is not accompanied by a change in the Stokes radius of the receptor (74 A) or buoyant density in metrizamide (1.24 g/ml). The effect of RNase A on the sedimentation of the receptor can be reversed by subsequent incubation with human placental RNase inhibitor or with rabbit anti-RNase A antibodies. Direct interaction was shown by chromatography of the receptor on RNase A Sepharose. Thus, the shift in sedimentation results from binding of RNase A to the receptor and, although this requires that the enzyme active site be available, enzymic activity is not responsible for the effect. The interaction of RNase A with the receptor occurs at low ionic strength; it does not occur at elevated ionic strength or after activation of the receptor by precipitation with ammonium sulfate.

Animals↗
PubMed1983

Use of chromatofocusing to distinguish estradiol receptor from ovarian-dependent and -independent rat mammary tumors.

Cytosol estradiol receptor from MTW9-D (ovarian dependent) and MTW9-MtT (ovarian independent) rat mammary tumors were fractionated by chromatofocusing, a procedure which separates proteins on an ion-exchange column as a function of isoelectric point. Receptor from MTW9-D usually fractionated as three peaks with mean pH at peak height of 7.5, 6.8, and 6.0. The intermediate peak at pH 6.8 was present in 90% of MTW9-D tumors examined but in only 20% of MTW9-MtT tumors. Treatment of cytosols with 20 mM sodium molybdate or 50 mM leupeptin did not change the chromatofocusing profiles. The pI 6.8 fraction of receptor bound quantitatively to DNA-cellulose after ammonium sulfate precipitation, while receptor in the other two peaks bound much less. The quantitative binding of a fraction of estradiol receptor characteristic of MTW9-D to DNA is consistent with the greater binding of unfractionated cytosol receptor from MTW9-D to DNA than the binding of receptor from MTW9-MtT. Sucrose gradient analysis of the pI 6.8 receptor showed a sedimentation coefficient slightly less than ovalbumin with a Stokes radius of 26 A as determined by agarose chromatography. The correlation of receptor binding to DNA with response to ovariectomy might make this form of receptor a potential marker of hormonal responsivity in mammary tumors.

Animals↗
PubMed1981

RNA inhibits estrogen receptor binding to DNA.

Cytosol from MTW9 rat mammary tumor contains a high molecular weight inhibitor of estrogen receptor binding to DNA. RNase treatment of crude preparations destroys inhibitory activity, whereas DNase or trypsin treatment are without affect, suggesting that some RNA molecule might be involved; in addition, RNA extracted from tumor cytosol was an effective inhibitor of estrogen receptor binding to DNA. A number of synthetic and natural RNA species were analyzed for inhibitory activity; a definite specificity was observed, with poly(G) > poly(U) > poly(A) or poly(C).

Animals↗
PubMed1981

Assessment of estrogen receptor--histone interactions.

Several different in vitro binding assays show that the estrogen receptor from rabbit uterus interacts selectively with purified histones from calf thymus. The estrogen receptor binds strongly to histones H2B and H2A, moderately to histones H3 and H4, and poorly to histone H1. In the presence of histones H2B or H2A, the position at which the estrogen receptor focuses in an isoelectric gradient is shifted to a more basic zone. Kinetic experiments show that, if histone H2B is bound to a DNA, the estrogen receptor dissociates more slowly from that DNA. The portion of the estrogen receptor molecule required for binding to histone H2B is relatively stable to tryptic digestion; in contrast, the portion of the receptor molecule responsible for DNA binding is promptly lost during limited tryptic digestion. These in vitro findings suggest that the mechanism by which the estrogen receptor selectively alters gene expression may involve specific contacts with histone molecules.

Animals↗
PubMed1980

Effect of photooxidation on the estrogen receptor from rat mammary tumor.

Photooxidation of estradiol receptor form MTW9 rat mammary tumor cytosol leads to a time-dependent loss of DNA-binding activity; this effect is pH-dependent. Binding of receptor to DNA does not protect the DNA-binding site from photooxidation. The estrogen binding site of the receptor is also susceptible to photooxidation, although the rate of loss of estradiol binding capacity is considerably less than that of DNA-binding capacity; this process is independent of pH. Binding of receptor to estradiol substantially protects the estradiol binding site from photooxidation. Sucrose gradient analysis of photooxidized receptor preparations showed no qualitative difference compared with nonirradiated controls. Similarly, the isoelectric focusing pattern of photooxidized receptor showed two peaks of radioactivity at pH approximately 5.6 and 6.3, as did nonirradiated receptor.

Animals↗
PubMed1980

Hormone, serum, and methylxanthine interactions in the regulation of DNA synthesis in organ-cultured rat mammary tumors.

Previous studies have shown that the growth of MTW9, a hormone-dependent rat mammary tumor, is stimulated by the presence of a mammosomatotropic tumor coimplant (MtTW10) but is inhibited by the administration of dibutyryl cyclic AMP (DBcAMP). This study examines the direct effect of serum taken from MtTW10-bearing WF rats (MtT serum) and of substances that increase cellular levels of cyclic AMP (cAMP) on DNA synthesis in organ-cultured MTW9. Explant DNA synthesis was significantly greater in the presence of MtT serum than in either normal female or male rat serum. Preparations of hormones known to be present in MtT serum failed to simulate the activity of MtT serum. Whereas 1 mM cAMP 1 mM did not alter DNA synthesis in MTW9 explants, inhibitors of cyclic nucleotide phosphodiesterases substantially suppressed the rate of [3H]thymidine incorporation into DNA. However, addition of MtT serum to cultures completely prevented the effects of these substances. This activity of MtT serum could not be duplicated by any of the following additions to the culture medium: normal female or male rat serum, National Institutes of Health (NIH) rat prolactin (2.5 micrograms/ml), NIH rat growth hormone (2.5 micrograms/ml), insulin (5 micrograms/ml), 17 beta-estradiol (5 micrograms/ml), or a hormone combination simulating the known endocrine constituents of MtT serum. The results suggested that the serum of the MtT-bearing animal contained an activity, unidentified at present, that could antagonize the growth-inhibitory action of the cAMP system and that may participate in the regulation of mammary tumor growth.

1-Methyl-3-isobutylxanthine↗
PubMed1980

Effect of subcutaneously administered 2,6,10,14-tetramethylpentadecane on plasmacytoma growth.

2,6,10,14-Tetramethylpentadecane (pristane), s.c. injected simultaneously with plasmacytoma inocula, enhances the transplantability of tumor cells. The effect is dose and time dependent. The enhancement is shown only by plasmacytoma (MOPC-315 and MPC-11) and not by the murine lymphosarcoma and chondrosarcoma tested. Various mechanisms, such as stress and depression of humoral and cellular immunity, have been considered.

Adrenocorticotropic Hormone↗