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Biomedical subjects

K Y Look

Publications and source records attributed to K Y Look.

At least 19 recordsLinked to original sources
PubMed2004

Role of lymphadenectomy in management of adenocarcinoma of the endometrium.

PURPOSE: To review the role of lymphadenectomy (LND) for patients with endometrial adenocarcinoma. METHODS: A review was undertaken of the English Language literature dealing with the role of LND for patients with endometrial adenocarcinoma (EC). RESULTS: The prognostic value of node status for EC patients has been recognized. LND performed by experienced surgeons has acceptable morbidity. Multiple series have suggested that significantly less external beam radiation is given to patients with known negative nodes. The decreased use of postop whole pelvic radiation has potential cost savings. However a survival advantage for LND has not yet been proven in a randomized clinical trials. United Kingdom investigators have begun a trial to determine if there is a demonstrable survival advantage for EC patients who undergo LND. CONCLUSION: Although the morbidity, potential cost savings, and prognostic impact of node status are well accepted, it remains controversial as to whether LND provides a survival advantage. Trials are underway.

Adenocarcinoma↗
PubMed2000

The Society of Gynecologic Oncologists Outcomes Task Force. Study of endometrical cancer: initial experiences.

OBJECTIVE: The aim of this study was to develop an outcomes measure, which incorporates patient reported information, for The Society of Gynecologic Oncologists (SGO) to establish benchmarks in the treatment of endometrial cancer and demonstrate quality to third parties. METHODS: The Outcomes Task Force (OTF) developed an outcomes tool that included preoperative, intraoperative, and 120-day-postoperative assessments. Measures included demographics, patient-reported health status (SF36), comorbid conditions, living status, satisfaction surveys, operative events and disease characteristics. Patients (n = 297) were surveyed at 11 pilot sites from 10/1/97 to 9/1/99. RESULTS: The mean age of patients was 64.4 years and their mean Quetelet index was 33.2 kg/m(2). Forty-eight percent were Medicare beneficiaries and 25% were HMO patients. Mean comorbidity score was 19.1 (maximum possible 100). This represents approximately three comorbidities per average patient. Seventy-four percent were FIGO stage I, 9% stage II, 11% stage III, and 5% stage IV. Forty percent were FIGO grade 1, 35% grade 2, and 24% grade 3. Ninety-two percent of patients were able to live independently preoperatively and 91% were independent postoperatively. Seventy-seven percent of patients underwent total abdominal hysterectomy, 8% radical abdominal hysterectomy, 9% laparoscopic hysterectomy, and 1% vaginal hysterectomy. Mean length of stay was 3. 3 days and mean operative time was 119 min. Ninety-nine percent were staged and 80% underwent lymph node sampling. Two patients required unplanned returns to surgery and 8 required blood transfusion (27 units total). Postoperatively, 20% received radiation therapy and 13% received cytotoxic chemotherapy. Mean satisfaction score (scale 0 to 100) preoperatively was 86 and postoperative was 83. SF36 component summaries were preoperatively and 120 days postoperatively: physical component 43.6 vs 43.1; mental component 49.1 vs 50.6. CONCLUSION: The SGO has developed a tool for assessing outcomes for the treatment of endometrial cancer that can be made available to the membership to assess and objectively demonstrate quality of care to third parties.

Endometrial Neoplasms↗
PubMed2000

Phase I trial of paclitaxel and etoposide for recurrent ovarian carcinoma: a Gynecologic Oncology Group Study.

A phase I study was performed to determine the maximum tolerated doses of intravenous etoposide and paclitaxel for women with previously treated persistent or recurrent ovarian cancer. Starting doses were paclitaxel 135 mg/m2 during 24 hours and etoposide 50 mg/m2/day for 3 consecutive days. The study was designed to escalate first the dose of etoposide, and then the dose of paclitaxel, in successive cohorts of patients. In an attempt to determine whether toxicity was affected by sequence of the drugs, the order of administration of the two drugs was reversed on alternate cycles. The starting doses of paclitaxel (135 mg/m2/24 hours) and etoposide (50 mg/m2/day x 3) caused severe neutropenia even with the addition of granulocyte colony-stimulating factor, and the trial was amended to administer the paclitaxel during 3 hours. However, this also proved too myelosuppressive without growth factor support. Twenty-one women were treated. A complete response was observed in one of nine patients with measurable disease, and a major decrease in CA-125 was noted in two patients who did not have measurable disease. Because of the severe myelosuppression observed in most patients, dose reduction was often required after the first cycle. The power to detect sequence-dependent variation in toxicity was minimal; however, no large differences were observed. A combination of the usual doses of these drugs will be difficult to administer in patients who have received previous chemotherapy for ovarian cancer.

Adult↗
PubMed2000

Inverted follicular keratosis of the vulvar skin: a lesion that can be confused with squamous cell carcinoma.

Although seborrheic keratoses of the vulva are described in textbooks, to our knowledge, inverted follicular keratosis has not been reported. A 27-year-old woman underwent an excisional biopsy for a small lesion of the left labium majus. Squamous cell carcinoma was considered in the clinical differential diagnosis. The initial pathologic diagnosis suggested squamous cell carcinoma in situ, and the consultation diagnosis was superficially invasive squamous cell carcinoma. On pathologic examination, a symmetrical, endophytic, epithelial tumor was observed consisting of a proliferation of basaloid cells with many areas of reactive squamous cells showing numerous squamous eddies, focal reactive nuclear atypia, and occasional mitotic figures. After the pathologic diagnosis of inverted follicular keratosis was made, a history of close perineal shaving and total body tanning was obtained. Because inverted follicular keratosis is postulated to be related to follicular injury, it is likely that the trauma of close shaving is a significant etiologic factor. There is less evidence that ultraviolet ray exposure is of etiologic importance.

Adult↗
PubMed2000

Signal transduction and biochemical targeting of ovarian carcinoma.

UNLABELLED: The purpose was to identify novel targets for the chemotherapy of ovarian carcinoma. METHODS: Assays were worked out to measure the activities of P1 kinase, PIP kinase and PLC in ovarian carcinoma samples and in OVCAR-5 cells and to compare the activities to those in normal ovaries. A method was also designed for measuring the concentration of the end product of signal transduction, IP3. RESULTS AND DISCUSSION: Signal transduction activity was markedly increased in ovarian cancer cells as shown by the increased steady-state activities of the three enzymes and the elevated concentrations of IP3. Inhibitors blocked activities of PI kinase (quercetin), PIP kinase (genistein), and lowered GTP concentration required for PLC (tiazofurin). Combinations of tiazofurin with quercetin, tiazofurin with genistein, and quercetin with genistein yielded a synergistic kill of ovarian cancer cells. Tiazofurin, quercetin and genistein are in various stages of clinical trials. CONCLUSION: The increased signal transduction activity provides novel, sensitive targets to chemotherapy in ovarian cancer cells.

Cell Survival↗
PubMed1999

Transforming growth factor-beta differentially inhibits epithelial ovarian carcinoma cells from primary and metastatic isolates without up-regulation of p21WAF1.

BACKGROUND: Transforming growth factor-beta (TGF-beta) is known to inhibit primary epithelial ovarian carcinoma cells. The mechanism by which this inhibitory response is achieved is poorly understood. Furthermore, whether this response is consistent in cells from metastatic sites compared with the primary site cells is unknown. The authors wanted to determine whether TGF-beta differentially inhibited ovarian carcinoma cells from primary tumor sites compared with metastatic sites and to establish whether this response was associated with up-regulation of p21WAF1 or overexpression of p53. METHODS: Tumor cells were purified from primary and metastatic sites in five patients with advanced epithelial ovarian carcinoma. TGF-beta effect at concentrations of 10, 1, and 0.1 ng/mL was determined by tritiated thymidine incorporation assay. Expression of p21WAF1 was determined by Northern and slot blot analysis. p53 was detected by immunocytochemistry. RESULTS: Metastatic tumor isolates were more responsive to the inhibitory effect of TGF-beta compared with their corresponding primary tumor isolates at 0.1 ng/mL. Increasing TGF-beta concentration conferred no additional inhibitory effect on the metastatic isolates; however, a dose-related phenomenon was observed in primary tumor isolates. p21WAF1 mRNA was up-regulated in only 2 of 10 primary and metastatic isolates. There was no correlation between TGF-beta responsiveness, p21WAF1 up-regulation, and p53 overexpression. CONCLUSIONS: Differential inhibition was observed between primary and metastatic tumor isolates. p21WAF1 up-regulation and p53 overexpression were not major modulators in TGF-beta regulation of primary and metastatic tumor growth in early passaged ovarian carcinoma cells.

Carcinoma↗
PubMed1999

Lack of efficacy of 24-h infusional topotecan in platinum-refractory ovarian cancer: A Gynecologic Oncology Group trial.

BACKGROUND: The aim of this study was to evaluate the efficacy of a more convenient topotecan administration schedule in the second-line treatment of advanced platinum-refractory ovarian cancer. METHODS AND MATERIALS: The Gynecologic Oncology Group conducted a Phase II trial of 24-h infusional topotecan (8.5 mg/m(2)), repeated every 3 weeks in 26 patients with platinum-refractory ovarian cancer (failure to respond to initial platinum-based treatment or development of recurrent disease within 6 months of completion of chemotherapy). RESULTS: Grade 4 neutropenia (85% of patients) and thrombocytopenia (12%) were the major toxicities encountered. Of the 25 patients evaluable for response, only a single patient experienced an objective response (4%). CONCLUSIONS: When employed at this dose and schedule (24-h infusion every 3 weeks), topotecan has minimal second-line activity in platinum-refractory ovarian cancer.

Adult↗
PubMed1998

A phase II trial of CPT-11 in recurrent squamous carcinoma of the cervix: a gynecologic oncology group study.

OBJECTIVE: To determine the response rate and associated toxicity of weekly CPT-11 in squamous carcinoma of the cervix. METHODS: From October 1994 to May 1996, the Gynecologic Oncology Group (GOG) conducted a Phase II trial in patients with recurrent squamous cervix carcinoma. The schedule employed weekly x4 intravenous CPT-11 at 125 mg/m2 followed with a 2-week rest, to be repeated until disease progression or unacceptable toxicity. Eligibility criteria were a GOG performance status of 0-2, adequate bone marrow reserve, adequate liver function, and serum creatinine <2 mg%. None of the patients had received prior chemotherapy other than radiation sensitizers. Standard GOG toxicity and response criteria were used. RESULTS: Fifty-four patients were entered into the trial. Three patients were ineligible because of wrong cell type (N = 2) or inadequate pathology material (N = 1). Two were inevaluable because of inadequate trial of drug. An additional 4 patients were inevaluable for response. Thus, 49 were evaluable for toxicity and 45 were evaluable for response. The median age of patients was 45 years (range, 29-71 years). The median number of weekly doses delivered was 7 (range, 1-46). The incidence of grade 4 neutropenia and anemia was 6.1 and 4.1%, respectively. Nineteen patients (38.8%) developed gastrointestinal (GI) toxicity including 8 with grade 3 and 11 with grade 4 severity. The overall response rate was 13.3% (6/45). There was 1 patient death from GI toxicity. There was one complete response of 8.8 months duration and 5 partial responses. CONCLUSION: OFFis schedule of CPT-11 exhibits modest activity with moderate toxicity in patients with recurrent squamous carcinoma of the cervix.

Adult↗
PubMed1998

Gynecologic cancers metastatic to the breast.

BACKGROUND: We report a series of gynecologic cancers metastatic to the breast, illustrating the diagnostic and prognostic implications of this rare event. STUDY DESIGN: By reviewing the gynecologic oncology data base, we identified 10 women with gynecologic cancer metastatic to the breast who were treated at Indiana University School of Medicine between August 1978 and February 1995. Medical records were reviewed for pertinent data concerning the presentation, evaluation, and treatment of the primary gynecologic malignancy and the metastatic breast tumor. RESULTS: The mean patient age was 56.8 years (range, 30-80 years). The most common gynecologic malignancy was ovarian cancer (five patients), followed by cervical cancer (two patients) and cancers of the vagina, endometrium, or peritoneum (one patient each). A palpable solitary breast mass was found in 8 of 10 patients (80%), and the upper outer quadrant of the breast was the most common site of tumor involvement. One woman presented with examination findings resembling inflammatory breast cancer, and one patient presented with multiple firm subcutaneous nodules. Despite further treatment, which in all cases consisted of systemic chemotherapy, 83% of the patients died with a breast metastasis within 1 year of presentation. CONCLUSIONS: Secondary breast malignancy should be suspected in any patient with a breast tumor and a known history of gynecologic cancer. A breast metastasis implies widespread tumor dissemination and a poor prognosis. Radical breast surgery should be avoided.

Adult↗
PubMed1998

A phase II trial of isotretinoin and alpha interferon in patients with recurrent squamous cell carcinoma of the cervix: a Gynecologic Oncology Group study.

From January 1993 through January 1996, 37 patients with unresectable squamous carcinoma of the cervix were entered on study and scheduled to receive oral isotretinoin 1 mg/kg per day with subcutaneous alpha interferon 6,000,000 units/day. A course was defined as 4 continuous weeks of therapy. The mean number of four-course cycles delivered was 1.8. One patient was ineligible because of wrong cell type and two were never treated. Thus, 34 patients were evaluable for toxicity. Eight patients were inevaluable for response. Five did not receive a complete 4-week course and three did not have additional tumor measurements; thus 26 were evaluable for response. Prior radiotherapy had been given to 25 patients and prior chemotherapy to 23 patients. There was no grade 4 neutropenia. The incidence of Gynecologic Oncology Group (GOG) grade 3 granulocytopenia and thrombocytopenia was 8.8% and 5.8%, respectively. Six patients (17.6%) developed grade 3 or worse nausea and vomiting. Four (11.7%) patients developed grade 3 neurologic symptoms. There were no complete responses and one partial response. The overall response rate was 3.8% (95% confidence interval, 0.1-19.6%). In this pretreated population, isotretinoin and alpha interferon in the dose and schedule employed exhibit minimal activity.

Adult↗
PubMed1998

Increased uridine kinase (ATP: uridine 5'-phosphotransferase; EC 2.7.1.48) activity in human and rat tumors.

The activity of uridine kinase (ATP: uridine 5'-phosphotransferase; EC 2.7.1.48), the rate-limiting enzyme of the UMP salvage pathway, was measured in human ovaries and ovarian carcinomas, in a spectrum of six rat hepatomas of different growth rates and in eleven normal rat tissues of high and low cell renewal rates. In a standard isotopic method developed for the 100,000 x g fraction, uridine kinase activity was linear for 20 min and proportional with protein concentration over a range of 0.1 to 0.8 mg per 0.1 ml reaction mixture. The apparent Kms for uridine, ATP and Mg++ in normal rat liver were 5.0, 3.4 and 1.5 mM and in the rapidly growing hepatoma 3924A, 0.8, 2.1 and 1.1 mM, respectively. In normal control ACl/N and Buffalo strain rat livers, kinase activity ranged from 159 to 180 nmol/h/mg protein. In hepatomas of slow and intermediate growth rates, kinase activity increased to 1.5- to 2.6-fold, and in hepatomas of rapid growth rates, to 5.1- to 5.8-fold over that of the relevant control, normal livers. When hepatoma 3924A tissue culture cells were plated and expressed their proliferative program, kinase activity increased to 2.1-fold in early log phase. To further clarify the linkage between uridine kinase and cell replicating capacity, the enzyme activity was measured in rat organs of high and low cell renewal. The kinase activity in liver of adult male Wistar rats was 176 +/- 6 nmol/h/mg protein. Activities in thymus, spleen and bone marrow were 4.7-, 2.1-, and 1.8-fold, respectively, of rat liver values; in adipose tissue, the activities were low. The decay rates of uridine kinase were examined in rats injected with a high dose of cycloheximide, which inhibits protein biosynthesis by 90%. The t(1/2) of the kinase in rat bone marrow was 0.64 h, in rat liver longer than 6 h. In human ovary and ovarian carcinoma, the apparent Kms for uridine were 11.5 and 0.5 mM, respectively. In human ovary (n = 3), kinase activity was 38 nmol/hr/mg protein; in ovarian carcinoma (n = 6), the activity increased to 5- to 13-fold over that in ovary. The positive linkage of uridine kinase activity with proliferation and transformation is apparent in human ovarian carcinomas and in rat hepatomas of different growth rates. Therefore, the increased uridine kinase activity should be an interesting target for anticancer chemotherapy.

Animals↗
PubMed1997

Collagenase expression in ovarian cancer cell lines.

BACKGROUND: There are several distinct forms of the matrix metalloproteinases (MMP) that degrade collagen in the extracellular matrix. Most involved in the metastatic process are collagenases exhibiting specificity for type IV collagen, the collagen that makes up the backbone of the basement membrane. We chose to examine the expression of one type IV collagenase, MMP-9, in several ovarian cancer cell lines. METHODS: Under the influence of phorbol esters such as TPA, the fibrosarcoma cell line HT1080 is known to express MMP-9. We examined the effect of TPA on MMP-9 expression with Northern analysis, and on MMP-9 collagenase activity with polyacrylamide gel electrophoresis-zymography, in HT1080 cells (positive control) and in six ovarian cancer cell lines: Hey, HeyA8, CAOV3, PA-1, SKOV3, and OVCAR3. Cells were grown to 70% confluence and the growth medium was changed to a serum-free medium for 24 hr. Cells were then treated with 12 ng/mL TPA or its vehicle for an additional 24 hr. Medium was collected for PAGE-zymographic analysis. The cells were lysed and their RNA collected for Northern analysis. RESULTS: PA-1, a teratocarcinoma, expressed more than 10-fold the amount of RNA for MMP-9 than the other lines following TPA treatment. Both Northern analysis and zymography showed that four of the six ovarian cell lines responded to TPA with increased collagenase expression and activity. The other two cell lines showed no MMP-9 activity either before or after TPA treatment. CONCLUSIONS: These results suggest that ovarian cancer cell lines express collagenase and that this expression may be regulated by phorbol esters which activate the protein kinase C pathway.

Base Sequence↗
PubMed1997

A prospective controlled trial of early postoperative oral intake following major abdominal gynecologic surgery.

OBJECTIVE: The objective was to determine whether, when compared with traditional dietary advancement, early oral intake following major gynecologic surgery leads to a reduction in the length of hospitalization. METHODS: Patients undergoing major abdominal gynecologic surgery were invited to participate in this study. After informed consent was obtained, they were randomized to one of two groups. The control group (group 1) was treated traditionally. Oral intake was initiated only after documentation of bowel function, which was defined by two of the following three criteria: (1) bowel sounds; (2) flatus or bowel movement; and (3) subjective hunger. Those assigned to the study group (group 2) were given a clear liquid diet on postoperative day 1. Once 500 cc was tolerated, a regular diet was given. Patients were evaluated on a daily basis for bowel sounds, flatus, bowel movement, hunger, nausea, vomiting, and need for nasogastric tube decompression. The groups were compared with regard to length of hospital stay, length of postoperative ileus, and incidence of adverse effects including nausea, vomiting, and postoperative complications. Statistical analyses were performed with the Student t and chi 2 tests. RESULTS: The demographic characteristics of the control (N = 47) and study groups (N = 49) were similar, with no significant differences in underlying medical conditions, prior abdominal surgery, or diagnosis of a malignancy. The groups did not vary statistically in the number of subjects who required postoperative antiemetics or postoperative biscodyl suppository. There was a statistically significant reduction in the length of hospitalization for those patients on the early feeding regimen. The average length of stay for group 1 was 4.02 days +/- 0.30 (SEM), while that for group 2 was 3.12 days +/- 0.16 (P = 0.008). While there was a significantly higher incidence of emesis in the study population, this was not associated with any untoward outcome, and this group actually tolerated a solid diet nearly one full day earlier (2.72 days +/- 0.14 vs 1.88 days +/- 0.14, P < 0.0001). CONCLUSIONS: Early postoperative oral intake results in a decreased length of hospitalization and is well tolerated when compared with traditional dietary management in patients undergoing abdominal surgery on a university gynecologic oncology service.

Enteral Nutrition↗
PubMed1997

Phase II trial of 5-fluorouracil and high-dose leucovorin in recurrent adenocarcinoma of the cervix: a Gynecologic Oncology Group study.

OBJECTIVE: The objective of the study was to determine the response rate and associated toxicity of 5-fluorouracil and high-dose leucovorin in patients with recurrent adenocarcinoma of the cervix. METHODS: Between December 1993 and October 1995, 53 patients with recurrent adenocarcinoma of the cervix were entered into a Phase II trial utilizing 200 mg/m2 of intravenous (iv) leucovorin with 370 mg/m2 of i.v. 5-fluorouracil daily for 5 days every 4 weeks for two courses, then every 5 weeks until disease progression. Eligibility criteria were a Gynecologic Oncology Group (GOG) performance status of 0-2, adequate bone marrow reserve, adequate liver function with bilirubin < or = 1.5 x normal and SGOT and alkaline phosphatase < or = 3 x normal, serum creatinine < or = 2 mg%, and signed informed consent. Standard GOG toxicity and response criteria were employed. RESULTS: Six patients were ineligible because of wrong cell type (N = 3), insufficient pathology materials (N = 2), or a second primary (N = 1); therefore 45 were evaluable for toxicity. Two patients did not have adequate response assessment; thus, 43 were evaluable for response. The median age was 50 (range, 28-79). Prior chemotherapy had been administered to 16 patients and radiotherapy to 40 patients. The median number of courses delivered was three (range, 1-22). The site of evaluable disease was pelvic in 25 patients and extra-pelvic in 18. Grade 3 neutropenia was seen in 17.8% (8/45) patients and 35.5% (16/45) developed grade 4 neutropenia. Grade 3 or 4 thrombocytopenia was seen in 1 patient each (2.1%). Grade 3 gastrointestinal toxicity with nausea, vomiting, diarrhea, dehydration, or stomatitis was of grade 3 severity in 11.1% (5/45) and grade 4 in 6.7% (3/45). There were four partial responses and two complete responses for an overall response rate of 14%. The duration of the complete responses was 17.3 and 8.8+ months. None of the patients with responses had previously received chemotherapy. CONCLUSION: The schedule of 5-fluorouracil and leucovorin exhibits moderate activity in patients with previously treated adenocarcinoma of the cervix and should be considered for a trial in chemotherapy-naive patients.

Adenocarcinoma↗
PubMed1997

Vulvar keratoacanthoma.

BACKGROUND: Keratoacanthomas are neoplastic proliferations of keratinocytes thought to originate from follicular epithelium. There is only one previously reported case in which keratoacanthoma involved the vulva. CASE: A 54-year-old woman presented with a nonulcerated vulvar lesion of approximately 1 month's duration. The lesion was 1 cm in diameter, located on the mid-right labium majus, with no surrounding induration or hyperkeratosis. The patient underwent wide local excision and the clinical-pathologic diagnosis was keratoacanthoma. After 2 years, she remains free of vulvar recurrence. CONCLUSION: Because of similarities in clinical presentation and histology to squamous cell carcinoma, the diagnosis of keratoacanthoma can be challenging. History and physical examination findings should be correlated with the histologic diagnosis, with consideration for dermatopathology consultation.

Diagnosis, Differential↗
PubMed1997

Regulation of the signal transduction program by drugs.

The purpose of this paper was to clarify critical aspects of the behavior of signal transduction activity in normal and cancer cells. 1. Signal transduction activity in the conversion of phosphatidylinositol through PI and PIP kinases and PLC to IP3 is regulated at multiple sites. In liver, hepatomas and human carcinomas PIP kinase is the rate limiting enzyme and PLC activity is present in great excess. 2. The steady-state signal transduction activity as measured by the three enzyme activities and IP3 concentration was markedly up-regulated in rat hepatomas of different growth rates. The steady-state specific activities of the three signal transduction enzymes were elevated in ovarian carcinomas as compared to normal ovary. Increased enzyme activities were also observed in human breast carcinoma cells as compared to normal human breast parenchymal cells. In breast, ovarian and rat hepatoma cells as they go through lag, log and plateau phases, IP3 concentration in the early lag phase increased 4.5- to 20-fold and PI and PIP kinase activities peaked in mid-log phase. These events returned to baseline levels in the plateau phase. PLC activity did not change. 3. The bone marrow PI and PIP kinase activities in 3-day starvation were decreased to 13% and IP3 concentration was reduced to 24%; at 1-day refeeding they returned to normal. PLC activity changed little. These alterations are in line with the rapid t1/2 degradation rates (12 min) of PI and PIP kinases observed in studies with cycloheximide. By contrast, PLC has a long half-life. 4. The molecular action of tiazofurin entails inhibition of IMP DH activity, decrease in GTP and IP3 concentrations, reduction of ras and myc oncogene expression, and signal transduction enzyme activities. These events are followed by induced differentiation and apoptosis. There are also decreases in enzyme activities which have rapid turnover, including TdR kinase, dTMP synthase, and GPRT. In vitro studies indicated that these events are abrogated by addition of guanine which restores GTP concentrations. Therefore, most or all these events were brought about by the reduced GTP concentration in the tiazofurin target cells. 5. Quercetin and genistein are able to inhibit PI and PIP kinase activities and reduce IP3 concentration in vivo and in tissue culture systems. These flavonoids are also inhibitors of cell proliferation and clonogenic ability in rat hepatoma 3924A and in human OVCAR-5 and MDA-MB-435 cells. Quercetin down-regulated the expression of c-myc and Ki-ras oncogenes and led to induced differentiation and apoptosis in K562 cells. Genistein reduced IP3 concentration in vivo and in the tissue culture system. Genistein is antiproliferative and has cytototoxicity in human carcinoma cells. All three drugs, tiazofurin, quercetin and genistein, act, in part at least, through depression of cellular IP3 concentration although the mechanisms may not be identical. 6. Quercetin and genistein, which attack different targets and different phases of the cell cycle, proved to be synergistic in OVCAR-5 cells. The impact of tiazofurin, genistein and quercetin is of interest because the drugs crucially inhibit the display of the neoplastic program of cells and lead to induced differentiation and apoptosis.

1-Phosphatidylinositol 4-Kinase↗