Postoperative expression of Cushing disease in a young male: metamorphosis of silent corticotroph adenoma?

SUMMARY

Silent corticotroph adenoma (SCA) is an unusual type of nonfunctioning pituitary adenoma (NFA) that is silent both clinically and biochemically and can only be recognized by positive immunostaining for ACTH. Under rare circumstances, it can transform into hormonally active disease presenting with severe Cushing syndrome. It might often produce diagnostic dilemma with difficult management issue if not thoroughly investigated and subtyped accordingly following surgery. Here, we present a 21-year-old male who initially underwent pituitary adenomectomy for presumed NFA with compressive symptoms. However, he developed recurrent and invasive macroadenoma with severe clinical as well as biochemical hypercortisolism during post-surgical follow-up. Repeat pituitary surgery was carried out urgently as there was significant optic chiasmal compression. Immunohistochemical analysis of the tumor tissue obtained on repeat surgery proved it to be an aggressive corticotroph adenoma. Though not cured, he showed marked clinical and biochemical improvement in the immediate postoperative period. Anticipating recurrence from the residual tumor, we referred him for cyber knife radio surgery.

LEARNING POINTS

Pituitary NFA commonly present with compressive symptoms such as headache and blurred vision. Post-surgical development of Cushing syndrome in such a case could be either drug induced or endogenous. In the presence of recurrent pituitary tumor, ACTH-dependent Cushing syndrome indicates CD. Rarely a SCA presenting initially as NFA can transform into an active corticotroph adenoma. Immunohistochemical marker for ACTH in the resected tumor confirms the diagnosis.

A phase II randomized clinical trial of the effect of metformin versus placebo on progression-free survival in women with metastatic breast cancer receiving standard chemotherapy

OBJECTIVES

Pre-clinical data suggest metformin might enhance the effect of chemotherapy in breast cancer (BC). We conducted a Phase II randomized trial of chemotherapy plus metformin versus placebo in metastatic breast cancer (MBC).

MATERIAL AND METHODS

In this double blind phase II trial we randomly assigned non-diabetic MBC patients on 1st to 4th line chemotherapy to receive metformin 850 mg po bid or placebo bid. Primary outcome was progression-free survival (PFS); secondary outcomes included overall survival (OS), response rate (RR), toxicity and quality of life (QOL). With 40 subjects and a type-one error of 0.2 (one-sided), a PFS hazard ratio (HR) of 0.58 could be detected with 80% power.

RESULTS

40 patients were randomized (22 metformin, 18 placebo) with a mean age of 55 vs 57 years and ER/PR positive BC in 86.4% vs 83.3% off metformin vs placebo, respectively. Mean BMI was 27kg/m2 in both arms. The majority of patients were on 1st line chemotherapy. Grade 3-4 toxicity occurred in 31.8% (metformin) vs 58.8% (placebo). Best response: Partial response 18.2% metformin vs 25% placebo, stable disease 36.4% metformin vs 18.8% placebo, progressive disease 45.4% metformin vs 56.2% placebo. Mean PFS was 5.4 vs 6.3 months (metformin vs placebo), HR 1.2 (95% CI 0.63-2.31). Mean OS was 20.2 (metformin) vs 24.2 months (placebo), HR 1.68 (95% CI 0.79-3.55).

CONCLUSION

In this population metformin showed no significant effect on RR, PFS or OS. These results do not support the use of metformin with chemotherapy in non-diabetic MBC patients.

Biochemical changes in cultivars of sweet oranges infected with citrus tristeza virus

Citrus fruit production occupies a place of considerable importance in the economy of the world including Pakistan. Tristeza disease caused by Citrus Tristeza Virus (CTV) exists in various forms that may or may not cause symptoms in the plants. The bioactive compounds and antioxidants are naturally present in plants and provide a defense mechanism that is generally accelerated in response to a stress. The objective of the present study was to target and analyze the citrus plants that were CTV positive to observe the changes in the enzymatic and non-enzymatic antioxidants of citrus (Sweet Oranges only). It was observed that in response to CTV infection, both the non-enzymatic antioxidants (total flavonoid, ascorbic acid, phenolic acid) and enzymatic antioxidants (catalase, superoxide dismutase and peroxidase) activities showed an increasing trend overall. The profiling of antioxidants in response to a viral infection may help in the discovery of new biomarkers that can be used as a monitoring tool in disease management.

Abstract P1-16-03: Phase II randomized clinical trial (RCT) of metformin (MET) vs placebo (PLAC) in combination with chemotherapy (CXT) in refractory locally advanced (LABC) or metastatic breast cancer (MBC)

Background: MET treatment of diabetes is associated with improved BC outcomes. Hirsch et al (Cancer Res 2009;69:7505-7511) suggested MET may act synergistically with CXT in BC rodent models. We conducted a double-blind Phase II RCT of CXT plus MET vs placebo in LABC/MBC.

Methods: Non-diabetic BC patients (pts) about to commence 1st-4th line CXT (prespecified anthracycline, taxane, vinorelbine, platinum or capecitabine; HER2 Rx permitted) for MBC or refractory LABC (any ER, PgR, HER2) were eligible if (i) age 18-75, (ii) ECOG 0-2, (iii) adequate hepatic, renal, bone marrow, cardiac function and (iv) measurable or evaluable disease. Those with CNS metastases, recent MET use or radiotherapy to target lesions, intake of ≥ 3 alcoholic drinks/day, history of lactic acidosis or current/planned pregnancy or lactation were ineligible. Randomization was to MET 850 mg po bid (or identical PLAC bid) with a 2 day ramp up of one tablet/day; dose was reduced/drug discontinued in a pre-specified manner for grade 2-4 toxicity. Disease status and toxicity/HRQOL were assessed at baseline and q9 weeks until progression. Primary outcome was progression-free survival (PFS); secondary outcomes included survival (OS), response and toxicity. With 40 subjects and type one error 0.2 (1-sided), a PFS HR of 0.58 could be detected with 80% power. PFS was analyzed using Cox proportional hazards regression.

Results: 40 pts were randomized (22 MET, 18 PLAC). Mean age 55.4 vs 56.9 years; ER/PgR+ in 86.4 vs 83.3%; time from 1st metastases to randomization 297 vs 405 days, in MET vs PLAC respectively. MET pts were more likely to have visceral metastases (95.5% vs 72.2% PLAC) and less likely to be HER2+ (9.1% vs 23.5% PLAC). CXT was 1st line in 68.2% MET and 66.7% PLAC pts. Toxicity - # events: Gr 4: 0 MET vs 1 PLAC, Gr 3: 14 MET vs 14 PLAC; Gr 1 or 2: 193 MET (mainly GI) vs 53 PLAC. Best response: PR 18.2% MET vs 22.2% PLAC, SD 31.8% MET vs 11.1% PLAC, PD 45.4% MET vs 50.0% PLAC, P = 0.41. Mean PFS 164 days MET vs 192 days PLAC; HR (MET vs PLAC) 1.14 (95% CI 0.59-2.2), 1-sided p=0.65. Mean OS 645 MET vs 831 PLAC days; HR (MET vs PLAC) 1.6, 95% CI 0.72-3.54, 1-sided p=0.88.

Conclusion: In these BC pts receiving 1st-4th line CXT, MET (vs PLAC) did not improve response rates, PFS or OS. Gr 1 and 2 toxicity was higher with MET than PLAC. These results do not support use of MET with CXT in refractory LABC/MET BC. MA32, an adjuvant trial of MET vs PLAC in early BC will provide information on MET in the adjuvant setting.

Funded by the Breast Cancer Research Foundation (New York) and Hold'em for Life Charity (Toronto)

Citation Format: Goodwin PJ, Ennis M, Cescon DW, Elser C, Haq R, Hamm CM, Lohmann AE, Pimentel I, Chang MC, Dowling RJ, Stambolic V. Phase II randomized clinical trial (RCT) of metformin (MET) vs placebo (PLAC) in combination with chemotherapy (CXT) in refractory locally advanced (LABC) or metastatic breast cancer (MBC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-16-03.

Breast cancer and dermatomyositis: a case study and literature review

A 49-year-old woman presents with an extensive violaceous rash, rapidly progressive proximal muscle weakness, and dysphagia to solids, consistent with a diagnosis of dermatomyositis. Two weeks later, she palpates a mass in her left breast and is diagnosed with her2-positive metastatic invasive ductal carcinoma of the breast. There is a well-established association between dermatomyositis and malignancy. However, the specific association between breast cancer and dermatomyositis has not been well characterized. No guideline for oncologists managing these patients has been established. Recently, 3 cases of breast cancer and dermatomyositis were diagnosed at our institution. A review of the literature was pursued to characterize the association between breast cancer and dermatomyositis. A review of 178 papers identified 22 cases of breast cancer with dermatomyositis. Most patients (71%) presented with stage iii or iv breast cancer. The median time between the diagnosis of breast cancer and the onset of dermatomyositis symptoms was 1 month. Three quarters of the patients were steroid-responsive and able to taper. Half the women with follow-up data experienced a documented cancer relapse associated with a new flare of cutaneous symptoms. The presence of dermatomyositis appears to be associated with more-advanced breast cancer stage and is most commonly associated with invasive ductal carcinoma. In our review, treatment of cancer alone is insufficient to adequately control the cutaneous and myopathic manifestations of dermatomyositis, which can significantly affect quality of life. A multidisciplinary approach, including close collaboration with rheumatologists and dermatologists, is therefore important in the diagnosis and management of oncology patients with dermatomyositis.

Duration of trastuzumab in patients with HER2-positive metastatic breast cancer in prolonged remission

BACKGROUND

Outcomes in metastatic breast cancer (mbc) positive for her2 (human epidermal growth factor receptor 2) are generally unfavourable. Trastuzumab has revolutionized the prognosis of her2-positive mbc. Some her2-positive mbc patients go into prolonged remission, and a few patients remain in remission even after discontinuation of trastuzumab, suggesting the possibility of a cure. In our practice, 4 her2-positive mbc patients treated with chemotherapy and trastuzumab have remained in remission on maintenance therapy for 5 years or more. Of those 4 patients, 2 have continued in remission after discontinuation of trastuzumab for more than 1 year. The objective of the present paper was therefore to address the duration of trastuzumab therapy in her2-positive mbc patients in prolonged remission.

METHODS

We conducted a literature review of the duration of trastuzumab in her2-positive mbc patients in remission. We also conducted an online survey of oncologists in Ontario to determine their treatment practices in her2-positive mbc patients.

RESULTS

The literature search found no specific evidence about the optimal duration of trastuzumab maintenance therapy in her2-positive mbc in prolonged remission. However, retrospective studies suggest predictive markers of good prognosis in patients in complete remission taking maintenance trastuzumab. Identifying those markers could lead to more personalized treatment. Our survey of oncologists about their treatment practices in her2-positive mbc patients revealed that 82.93% of respondents (n = 34) follow the currently available guidelines.

CONCLUSIONS

With the emergence of patients in prolonged remission, duration of trastuzumab in her2-positive mbc has become an important and relevant clinical question worldwide. Collaborative efforts are needed for the further study of this topic.

Prognostic effect of early treatment of paraneoplastic limbic encephalitis in a patient with small-cell lung cancer

Paraneoplastic neurologic syndrome (pns) is an uncommon manifestation of cancer and may present before any symptoms of malignant disease. This syndrome occurs in fewer than 1 of every 10,000 patients diagnosed with a malignancy. Anti-neural antibodies have been associated with pns, suggesting that this condition may reflect immune mechanisms. Depending on the region of the nervous system that has been affected, pns can have a number of manifestations. Paraneoplastic limbic encephalitis (ple) stems from involvement of the limbic system and may present with seizures and changes in mood, memory, and personality. The present report describes the case of a 55-year-old man presenting with ple in the setting of small-cell lung cancer, with subsequent improvement of his neurologic symptoms. The value of rapid diagnosis and multidisciplinary management of this syndrome are discussed.

P5-08-04: Mammographic Microcalcifications and Breast Cancer Tumorigenesis: A Radiologic-Pathologic Analysis

Background

Microcalcifications (MCs) are tiny deposits of calcium in breast soft tissue. They serve as key diagnostic radiological features for localization of malignancy. Approximately 30% of early invasive breast cancers have fine, granular MCs detectable on mammography; however, their role in breast cancer tumorigenesis is currently unknown. The purpose of this study was to investigate the relationship between mammographic MCs and breast cancer pathology.

Methods: A retrospective chart review was performed for 882 women treated for breast cancer between 2000–2010 at St. Michael's Hospital. Demographic information (age and menopausal status), tumor pathology (size, histology, grade, nodal status and lymphovascular invasion), hormonal status (ER and PR), HER-2 overexpression and presence of MCs were collected for breast cancer patients. Chi-square tests were performed for categorical variables and t-tests were performed for continuous variables. All tests were two-sided and p-values less than 0.05 were considered statistically significant.

Results: A total of 826 patient charts were included; 56 (6.4%) patients had metastatic carcinoma and were excluded from analysis. Only 37.0% (326/882) of the patients presented with mammographic MCs. Patients were more likely to have MCs if they were HER-2 positive (51%) as opposed to being HER-2 negative (33.4%) (p=0.001). There was a significant association between MCs and being perimenopausal with a mean age of 50 (65.2%) (p=0.012). Patients with invasive ductal carcinomas (39.7%) were more likely to present with MCs than were patients with other tumor histology (p=0.001). There was a positive correlation between MCs and tumor grade (p=0.051), with grade III tumors (41.85%) presenting with the most MCs, followed by grade II (37.95%) and grade I (29.8%). There was no significant association between mean age, mean tumor size, ER and PR status with the presence of MCs.

Conclusion: This is the largest study that suggests the appearance of MCs on mammograms is strongly associated with HER-2 overexpression, invasive ductal carcinoma and perimenopausal status. Since HER-2 is implicated in mediating aggressive tumor growth and metastasis, future studies should investigate the molecular pathways underlying HER-2 overexpression and MC development. This would help better understand the role of MCs in breast cancer tumorigenesis.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-08-04.

Improvement in the quality of care for patients with locally advanced breast cancer through implementation of an integrated electronic care pathway

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Background: Locally advanced breast cancer (LABC) refers to the most advanced stage of non-metastatic tumours with an incidence of approximately 10% in newly diagnosed breast cancers. Currently, for optimal care, patients with LABC require a multidisciplinary approach including coordinated planning with medical, surgical and radiation oncologists. We created an interactive electronic care pathway and self populating quality assurance database at St. Michael’s Hospital (SMH) to facilitate multidisciplinary teams to track LABC patient histories and patient treatments in order to coordinate therapy effectively and expedite care (LABC E-PATH).

Methods: This is an observational before-and-after cohort study of patients with LABC with a retrospective review pre-implementation and prospective collection of clinical data post-implementation. The completeness of workup and the timeliness of treatment pre- and post-implementation of the LABC E-PATH in May 2010 were assessed.

Results: With the implementation of the LABC E-PATH in May 2010 at SMH, the delay between the identification of the patient as LABC and their referral to a medical oncologist for treatment for their LABC decreased from a median of 9 days pre-implementation, (range 0-780 days) to 1 day post-implementation, (range 0-52 days). The time between referral to medical oncologist and the start of their chemotherapy treatment decreased from a median of 12 days to 9 days (pre-implementation: range = 4 to 494, post-implementation: range = 0 to 39). All pre-treatment staging was completed faster post-implementation of the LABC e-path than pre-implementation, expediting time to initiation of chemotherapy. The number of referrals for LABC to the SMH program increased from < 1 patient per month to 5 patients per month post-implementation.

Conclusions: The LABC E-PATH at SMH has achieved its goal of expediting care for this patient population. It has also ensured timely and appropriate resource allocation. This unique system may also be applied to other disease sites where coordination of a multi-disciplinary team is critical for appropriate patient management.

Results of a pilot study of a web-based care plan to meet the communication needs of breast cancer survivors and their primary care physicians

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Background: Following treatment, breast cancer patients (BCPs) can feel “lost in transition”. Family practitioners (FP) also report feeling ill-equipped to provide follow-up care to breast cancer patients. In this 3-phase qualitative pilot study we designed, implemented and evaluated a multi-faceted care plan (MCP) to address the information/communication needs of BCPs and their FPs.

Methods: We first conducted focus groups and interviews with 35 participants from 3 stakeholder groups (BCPs, FPs and oncology team), to identify specific information and communication needs. A MCP was designed based on these findings. The MCP was then evaluated via focus groups and interviews with 26 participants. Interviews and focus groups were audiotaped, transcribed and content analysed for emergent themes and patterns.

Results: Pre-implementation, participants identified communication needs pertinent to BCPs and FPs. Patients commented that web-based, paper-based and human resources components are essential to any care plan. Patients did not focus solely on the post-treatment period, but rather spoke of evolving needs throughout their cancer journey. FPs indicated that any tools to support them must distill important information in a readily accessible and easy-to-use format. Based on this needs assessment, a MCP was designed and implemented for BCPs and FPs. This consisted of tailored websites, as well as paper-based care plans and a patient booklet. Patients provided positive feedback about the MCP, indicating that it was effective at addressing many of their needs and commented “I wish I’d had this before”. Suggestions for future improvements to the MCP included greater emphasis on health-and-wellness post-treatment. In addition, some patients voiced resistance to the terms “survivor” and “survivorship” in materials, as they did not self-identify with such terms.

Conclusions: This MCP shows promise in addressing the information/communication needs of BCPs and FPs who care for them. Next steps include tool refinement, further evaluation, and planning for more extensive implementation.

Abstract P5-10-24: A Pragmatic Review of Adjuvant Chemotherapy Regimens in Early-Stage Breast Cancer — Hematologic Toxicities Experienced in a Single Institution

Background: Chemotherapy-related toxicities are associated with substantial morbidity, mortality, and health care expenditures. Three newer common adjuvant chemotherapy regimens - 5-fluorouracil, epirubicin, cyclophosphamide plus docetaxel (FEC-D), docetaxel plus cyclophosphamide (TC), and docetaxel, carboplatin plus trastuzumab (TCH) - have emerged as promising therapies. The toxicities experienced with these chemotherapeutic regimens were reviewed in a clinical practice setting outside of clinical trial.

Patients and Methods: Patients (pts) with early-stage breast cancer treated with adjuvant chemotherapy (FEC-D; TC; TCH) at St. Michael's Hospital in Toronto, Canada, between August 2006 and May 2010 were identified. Charts were audited for the presence of neutropenia (defined asabsolute neutrophil count (ANC) &lt; 1.0x109/L), use of granulocyte-colony stimulating factor (G-CSF), incidence of febrile neutropenia (FN; defined as a single oral temperature ≥38.3 0Celsius, or oral temperature ≥38.0 0C lasting over 1 hour, with an ANC &lt; 1.0x109/L).

Results: Overall, 175 pts were reviewed in this study. The rate of neutropenia, FN, and use of primary prophylaxis with G-CSF are summarized in the table below for each regimen. Thirty pts on FEC-D (25.2%) experienced significant complications resulting in dose delay, dose reduction, and discontinuation of chemotherapy, as did 9.1% of pts on TC, and 27.3% of pts on TCH. There was one death associated with FEC-D while on G-CSF.

Conclusion: Our institution reports FN rates higher than originally reported in all three chemotherapy regimens with a greater hematologic toxicity profile with FEC-D. Further investigation with larger patient cohorts is warranted, to determine if there is a need for primary prophylaxis with G-CSF in patients receiving FEC-D, TC, and TCH.

Table 1: Outcomes associated with FEC-D, TC, and TCH chemotherapy regimens

Evaluation of hospitalized infants and young children with bronchiolitis - a multi centre study

Four hundred and twenty nine young children with bronchiolitis admitted consecutively in different hospitals of Bangladesh were evaluated. Three hundred and forty eight children studied for their putative risk factors, clinical profile, management and the outcome. Both cases and controls were examined for respiratory syncytial virus (RSV) antibody status. The diagnosis of bronchiolitis was made on the basis of first attack of wheeze in previously healthy children below two years of age. Detailed history including the possible risk factors, the management and daily follow-up on the ward and the outcome at discharge were documented through a structured questionnaire. Chest x-ray was done in each case to find out the radiological changes. Blood of 266 patients and 30 controls were studied for RSV IgM and IgG antibody by ELISA. There were 66% male and 34% female children. The median age of the children was 3.0 months and 82.7% were below 6 months of age. Most of the babies were born term (88%), with ABW (73%), by normal vaginal delivery (88%). Exclusive or predominant breast-feeding were given in 72% cases. The location of the patient was rural in 55% cases. Around half of the parents were illiterate or slightly educated (up to 5 years schooling) fathers 46.5% and mothers 56% and majority of the parents were poor (74%). In 52% cases the number of family members in one room were four or more. Half of the parents (52%) were smokes and there was atopy in 26.5% families. The clinical features of bronchiolitis were mostly cough (99%), respiratory distress (97%), feeding difficulty (93%) and fast breathing (96%) (median RR 68/min). Fever (1000F or more) was in only 33% cases, though parents complained in 90% cases. All children (100%) had wheeze and crackles in lungs in 96% cases. Liver could be palpable in 83% and spleen in 42% cases. Important radiological features were increased translucency (96%), increased interstitial markings (87%), hyperinflation (75%) and streaky densities (61%). In 69.6% cases TLC was 12,000 or less and only 15% with a neutrophil fraction greater than 60%. Children were positive for IgM antibody in 43.6% cases and both IgM and IgG in 5.3% cases. The main modalities of treatment were antibiotics (99%) (Ampicillin, 76%), oxygen therapy (83%), nebulised salbutamol (76%) and intravenous fluid (51%). The median duration of hospital stay was 4 days. Most of the children were discharged with improvement (96%) with 2% mortality. Not a single case was diagnosed as bronchiolitis in hospitals outside Dhaka. Cefrtiaxone (72.5%) and parenteral steroids (70.5%) were the mainstay of therapy there.

NKIATRE is a novel conserved cdc2-related kinase

The mitogen-activated protein kinases (MAPKs) and the cyclin-dependent kinases (CDKs) are key mediators of cell proliferation in response to extracellular signals. Recent additions to each of these families and the identification of kinases with structural features of both have provided insights into fundamental processes, such as cell division and differentiation. To identify novel serine kinases with features of MAPKs or CDKs, a degenerate PCR-based amplification approach was undertaken. The 57- and 52-kDa isoforms of a novel protein kinase, termed NKIATRE, were molecularly cloned from rat brain and jejunum cDNA libraries. Like the MAPKs, NKIATRE has a Thr-Xaa-Tyr motif in kinase subdomain VIII. NKIATRE also shows close homology to the cyclin-dependent kinase class of protein kinases and the cdc2-related kinases NKIAMRE, KKIALRE, and KKIAMRE, containing both conserved inhibitory phosphorylation sites and a putative cyclin-binding domain. Two isoforms of NKIATRE that differ in their carboxy-terminal ends have been identified. A functional nuclear localization signal is specific to the longer 57-kDa alpha isoform. Sequence similarity to the putative human tumor suppressor gene NKIAMRE, which is lost in leukemic patients with chromosome 5q deletions, suggests that NKIATRE may have a role in restricting cell growth or maintaining differentiation.

Escherichia coli Shiga toxins induce apoptosis in epithelial cells that is regulated by the Bcl-2 family

Human intestinal cells lack globotriaosylceramide (Gb(3)), the receptor for Shiga toxin-1 (Stx1) and Shiga toxin-2 (Stx2). Therefore, the role of these toxins in mediating intestinal disease during infection with Shiga toxin-producing Escherichia coli is unclear. The aims of this study were to determine whether Stx1 and Stx2 induce apoptosis in epithelial cells expressing (HEp-2, Caco-2) or lacking (T84) Gb(3) and to characterize the role of the Bcl-2 family. Stx1 (12.5 ng/ml) induced apoptosis in both HEp-2 (21.9 +/- 7.9% vs. 0.8 +/- 0.3%, P = 0.01) and Caco-2 (10.1 +/- 1.2% vs. 3.1 +/- 0.4%, P = 0.006) cells but not in Gb(3)-deficient T84 cells. Toxin-mediated apoptosis of HEp-2 cells was associated with enhanced expression of the proapoptotic protein Bax. Inhibition of caspase activation prevented toxin-stimulated apoptosis. In addition, overexpression of Bcl-2 by transient transfection blocked Stx1-stimulated cell death. These findings indicate that Shiga toxins produced by E. coli signal Gb(3)-expressing epithelial cells to undergo apoptosis in association with enhanced Bax expression, thereby resulting in activation of the caspase cascade.

Mitoxantrone-DHAP with GM-CSF: an active but myelosuppressive salvage therapy for relapsed/refractory aggressive non-Hodgkin's lymphoma

This study was designed to evaluate the efficacy and toxicity of dose intensifying DHAP (dexamethasone, cytarabine and cisplatin) salvage chemotherapy by adding mitoxantrone with GM-GSF support in patients with relapsed or refractory non-Hodgkin's lymphoma (NHL). From March 1992 to January 1995, 22 patients with intermediate and high grade (aggressive) NHL refractory or relapsed after adriamycin containing chemotherapy regimens were treated with M-DHAP+GM-CSF, (dexamethasone 40 mg i.v. days 1-4, cisplatin 100 mg/m2 i.v. by continuous infusion over 24 hours on day 1, cytarabine 2 gm/m2, i.v. every 12 hours for 2 doses on day 2, mitoxantrone 10 mg/m2 i.v. on days 3 and 4 and GM-CSF 250-500 microg/m2 s.c. daily beginning day 5 until absolute neutrophil count recovery. Most patients had poor prognostic factors including primary refractory disease (18/22), bulky disease (12/22), elevated LDH (9/22), or bone marrow involvement (8/22). All 22 patients were evaluable. The overall response rate was 41% (CR 23% and PR 18%). There were three toxic deaths, all related to sepsis. Median progression free survival (PFS) and overall survival (OS) rates were 5.2 months and 11.8 months respectively. At the same time of the analysis two patients were alive after high-dose therapy and bone marrow transplant at 34 and 36 months follow-up and two were alive with disease. The maximal acceptable dosage of mitoxantrone was 10 mg/m2 x 2 due to serious hematologic toxicity. Treatment delays and dose reductions compromised delivering the optimal dose intensity of M-DHAP. A poor prognostic group of patients with refractory or recurrent aggressive lymphoma, many of whom were not eligible for high-dose therapy and stem cell transplantation were treated with repeated cycles of dose intensified DHAP with growth factor support. Although M-DHAP had therapeutic activity even in patients considered to have primary refractory disease, myelosuppression was dose limiting and frequently limited the number of cycles. Therefore, if M-DHAP is to be further evaluated, therapeutic results may be improved further by incorporating strategies to reduce myelotoxicity such as the use of growth factors to reduce platelet transfusion requirements or the use of autologous stem cell support after each cycle.

Identification of NKIAMRE, the human homologue to the mitogen-activated protein kinase-/cyclin-dependent kinase-related protein kinase NKIATRE, and its loss in leukemic blasts with chromosome arm 5q deletion

Human acute leukemia and myelodysplasia are often associated with an interstitial deletion in chromosome arm 5q. The deleted region is hypothesized to contain tumor suppressor loci that are critical to the maintenance of normal hematopoiesis. We have identified NKIAMRE, a novel cyclin-dependent kinase-related molecule that is closely related to the rat serine/threonine kinase NKIATRE. Human NKIAMRE localizes to chromosome band 5q31.1, centromeric to the interleukin 9 locus and telomeric to IFN response factor-1. NKIAMRE was deleted at both alleles in 9 of 18 leukemic samples with chromosome band 5q31 abnormalities studied by fluorescence in situ chromosomal hybridization. NKIAMRE loss may be an important determinant of dysmyelopoiesis.

Inhibition of apoptotic signaling pathways in cancer cells as a mechanism of chemotherapy resistance

The extracellular microenvironment of tumors differs from most normal tissues. Many tumors have relatively acidic extracellular pH (pHe), although the intracellular pH (pHi) of tumor cells remains normal due to efficient maintenance of a large proton gradient across the membrane. This difference between tumors and normal tissues might be exploited therapeutically by disruption of the mechanisms which regulate pHi, so that tumor cells are killed by intracellular acid-induced injury. To investigate the mechanisms by which intracellular acidification leads to cell death, we have studied the roles of the anti-apoptotic gene bcl-2 and its pro-apoptotic binding partner bax, the Stress Activated Protein Kinases (SAPK/JNK), and the caspase proteases in mediating acid-induced cell death. While expression of bcl-2 in human bladder cancer MGH-U1 cells had no effect on acid-induced death, overexpression of bax enhanced cell death, consistent with its pro-apoptotic function. Inhibition of SAPK, through expression of a dominant negative mutant of its activator, SEK1 protected cells from acid-induced cell death. Caspase activation, as measured by poly (ADP-ribose) polymerase cleavage, was absent after lethal intracellular acidification. Consistent with this observation, inhibition of ICE proteases by the peptide z-VAD.fmk did not protect against acid-induced cell killing. We conclude that acid-induced cell death depends on bax and on SAPK signaling pathways but not on the caspase proteases. Therapeutic manipulation of bax and SAPK may enhance acid-induced tumor cell killing.

Investigation of myotonic dystrophy kinase isoform translocation and membrane association

Myotonic dystrophy is caused by the expansion of a CTG repeat found in the 3'-untranslated region of the myotonic dystrophy kinase. The mechanism of disease and the role of the kinase are currently obscure. Here we begin the investigation of domain structure/function correlations to aid in determining its normal function. Expressed full-length protein and protein truncated before a C-terminal hydrophobic domain were compared. In vitro, signal peptide function and protection of kinase by microsomal membranes were absent; thus, it is not translocated, as previously proposed. However, full-length kinase expressed in insect cells was found in fractions enriched for membranes and decorated mitochondria. The truncated form was found primarily in the cytosol. The kinase was present as two self-associated, disulfide-linked complexes. The majority of full-length kinase was found in the larger of the two complexes, while almost all of the truncated form was found in the smaller. Thus, the C-terminal region confers a higher order of self-association. Furthermore, full-length kinase expressed in COS-1 cells was present as high molecular weight complex, while the truncated form was present as monomer species. These experiments indicate that the myotonic dystrophy kinase is not membrane-integrated, but that it may have a molecular organization which favors peripheral association with membranes.

Differential effects of all-trans and 13-cis-retinoic acid on mRNA levels of nuclear retinoic acid receptors in rat lung and liver

The effects of three retinoids, all-trans-retinoic acid (all-trans-RA), 13-cis-RA, and etretin were examined on mRNA abundance of nuclear retinoic acid receptors (RAR-alpha, beta, and gamma) in lung and liver of retinol deficient and chow fed rats. All-trans-RA increased lung RAR-beta mRNA levels 5 or 11-fold in chow fed and retinol deficient rats, respectively. Similarly to lung, liver RAR-beta mRNA levels were 3-fold higher in retinol deficient rats fed all-trans-RA than the rats fed cottonseed oil. Lung RAR-gamma mRNA levels were also induced 2-fold by all-trans-RA. In contrast to this, 13-cis-RA and etretin at equimolar doses failed to enhance lung or liver RAR-beta or lung RAR-gamma mRNA levels in retinol deficient rats. These data for the first time show that all-trans-RA is more effective than its 13-cis-isomer in regulating the expression of RAR-beta and gamma transcripts in adult animal.

Retinoic acid affects the expression of nuclear retinoic acid receptors in tissues of retinol-deficient rats

The multitude of biological effects of the vitamin A metabolite, retinoic acid, are mediated by nuclear retinoic acid receptors (RARs), which are members of the steroid/thyroid hormone receptor superfamily. RAR-alpha, -beta, and -gamma are encoded by three genes from which multiple isoforms can be generated. Recent studies suggest that the expression of at least some RAR isoforms can be regulated by retinoic acid in certain cell lines. Here we examined regulation of RAR expression in the adult animal. RARs were analyzed by Northern blots from lung, liver, and testes of retinol-deficient rats. Retinol deficiency caused a 65-70% decrease in the mRNA levels of lung and liver RAR-beta, whereas no change was observed in RAR-alpha and -gamma mRNA levels in these organs. In the testes of retinol-deficient animals, two transcripts, RAR-alpha 1 (3.7 kb) and RAR-alpha 2 (2.8 kb), were detected as compared with one RAR-alpha 1 (3.7 kb) transcript in retinol-sufficient testes. When retinol-deficient rats were orally administered 1 dose of retinoic acid (100 micrograms per rat), lung RAR-beta mRNA levels started to increase after 1 hr and reached a 16-fold higher level after 4 hr; after 4 hr these retinoic acid-fed rats also showed a 7-fold increase in liver RAR-beta mRNA levels as compared with levels in the retinol-deficient rats. In contrast, liver, lung, and testes RAR-alpha transcripts remained either unchanged or showed only a slight increase in response to retinoic acid. RAR-gamma was constitutively expressed in lung, and its mRNA levels were induced 2-fold by retinoic acid. These results show tissue diversity in the rapid induction of RAR-beta and RAR-gamma by retinoic acid in the adult animal and suggest distinct roles for the various receptor isoforms in the control of the retinoid response.

Expression of nuclear retinoic acid receptors in rat adipose tissue

Expression of nuclear retinoic acid receptors (RAR-alpha, beta and gamma) was examined by Northern blots in rat lung, liver, and adipose tissue. Three transcripts of approximate sizes 7.3, 3.7, and 2.8 Kb were detected in adipose tissue. In contrast to adipose tissue only 3.7 and 2.8 Kb mRNA species were detected in liver and lung. Two RAR-beta gene transcripts (3.3 and 3.0 Kb) were expressed in adipose tissue, liver, and lung. RAR-gamma mRNA (3.36 Kb) was detected in adipose tissue and lung. The distribution of three RARs in adipose tissue suggests the physiological role of retinoic acid in the regulation of specific genes via RARs in adipocytes.

Retinoic acid rapidly induces lung cellular retinol-binding protein mRNA levels in retinol deficient rats

Retinol deficiency resulted in decreased mRNA levels for cellular retinol-binding protein (CRBP) in the lungs and the testes. The level of lung CRBP mRNA increased 2.3-fold one hour after oral administration of retinoic acid to retinol deficient rats. In contrast, testicular CRBP mRNA level was not influenced. Our data indicate that retinoic acid regulates CRBP mRNA level in the whole animal and this rapid effect suggests a role for CRBP in the mechanism of vitamin A action at genomic level.