Transforming
growth factor α (TGF-α) is an autocrine growth factor for human
cancer. Overexpression of TGF-α and its specific receptor, the
epidermal growth factor receptor (EGFR), is associated with ...aggressive
disease and poor prognosis. The EGFR has been proposed as a target for
anticancer therapy. Compounds that block ligand-induced EGFR activation
have been developed. ZD-1839 (Iressa) is a p.o.-active, quinazoline
derivative that selectively inhibits the EGFR tyrosine kinase and is
under clinical development in cancer patients. The antiproliferative
activity of ZD-1839 alone or in combination with cytotoxic drugs
differing in mechanism(s) of action, such as cisplatin, carboplatin,
oxaliplatin, paclitaxel, docetaxel, doxorubicin, etoposide, topotecan,
and raltitrexed, was evaluated in human ovarian (OVCAR-3), breast
(ZR-75–1, MCF-10A ras ), and colon cancer (GEO) cells
that coexpress EGFR and TGF-α. ZD-1839 inhibited colony formation in
soft agar in a dose-dependent manner in all cancer cell lines. The
antiproliferative effect was mainly cytostatic. However, treatment with
higher doses resulted in a 2–4-fold increase in apoptosis. A
dose-dependent supra-additive increase in growth inhibition was
observed when cancer cells were treated with each cytotoxic drug and
ZD-1839. The combined treatment markedly enhanced apoptotic cell death
induced by single-agent treatment. ZD-1839 treatment of nude mice
bearing established human GEO colon cancer xenografts revealed a
reversible dose-dependent inhibition of tumor growth because GEO tumors
resumed the growth rate of controls at the end of the treatment. In
contrast, the combined treatment with a cytotoxic agent, such as
topotecan, raltitrexed, or paclitaxel, and ZD-1839 produced tumor
growth arrest in all mice. Tumors grew slowly for approximately 4–8
weeks after the end of treatment, when they finally resumed a growth
rate similar to controls. GEO tumors reached a size not compatible with
normal life in all control mice within 4–6 weeks and in all single
agent-treated mice within 6–8 weeks after GEO cell injection. In
contrast, 50% of mice treated with ZD-1839 plus topotecan,
raltitrexed, or paclitaxel were still alive 10, 12, and 15 weeks after
cancer cell injection, respectively. These results demonstrate the
antitumor effect of this EGFR-selective tyrosine kinase inhibitor and
provide a rationale for its clinical evaluation in combination with
cytotoxic drugs.
Purpose: The epidermal growth factor receptor (EGFR) autocrine signaling pathway is involved in cancer development and progression.
EGFR inhibitors such as C225 (cetuximab), a chimeric human-mouse ...anti-EGFR monoclonal antibody, and ZD1839 (gefitinib), a
small molecule EGFR-selective tyrosine kinase inhibitor, are in advanced clinical development. The potential emergence of
cancer cell resistance in EGFR-expressing cancers treated with EGFR inhibitors could determine lack of activity of these drugs
in some cancer patients. Vascular endothelial growth factor (VEGF) is secreted by cancer cells and plays a key role in the
regulation of tumor-induced endothelial cell proliferation and permeability. ZD6474 is a small molecule VEGF flk-1/KDR (VEGFR-2)
tyrosine kinase inhibitor that also demonstrates inhibitory activity against EGFR tyrosine kinase.
Experimental Design: The antitumor activity of ZD1839, C225, and ZD6474 was tested in athymic mice bearing human GEO colon cancer xenografts.
GEO cell lines resistant to EGFR inhibitors were established from GEO xenografts growing in mice treated chronically with
ZD1839 or C225. Expression of EGFR was evaluated by flow cytometry. Expression of various proteins involved in intracellular
cell signaling was assessed by Western blotting. Tumor growth data were evaluated for statistical significance using the Student’s
t test. All P s were two-sided.
Results: Although chronic administration of optimal doses of C225 or ZD1839 efficiently blocked GEO tumor growth in the majority of
mice, tumors slowly started to grow within 80–90 days, despite continuous treatment. In contrast, continuous treatment of
mice bearing established GEO xenografts with ZD6474 resulted in efficient tumor growth inhibition for the entire duration
of dosing (up to 150 days). ZD6474 activity was also determined in mice pretreated with ZD1839 or C225. When GEO growth was
apparent after 4 weeks of treatment with EGFR inhibitors, mice were either re-treated with EGFR inhibitors or treated with
ZD6474. GEO tumor growth was blocked only in mice treated with ZD6474, whereas tumor progression was observed in mice re-treated
with C225 or ZD1839. GEO tumors growing during treatment with C225 or with ZD1839 were established as cell lines (GEO-C225-RES
and GEO-ZD1839-RES, respectively). Cell membrane-associated EGFR expression was only slightly reduced in these cell lines
compared with parental GEO cells. Western blotting revealed no major change in the expression of the EGFR ligand transforming
growth factor α of bcl-2, bcl-xL, p53, p27, MDM-2, akt, activated phospho-akt, or mitogen-activated protein kinase. However,
both GEO-C225-RES and GEO-ZD1839-RES cells exhibited a 5–10-fold increase in activated phospho-mitogen-activated protein kinase
and in the expression of cyclooxygenase-2 and of VEGF compared with GEO cells. GEO-C225-RES and GEO-ZD1839-RES growth as xenografts
in nude mice was not significantly affected by treatment with either C225 or ZD1839 but was efficiently inhibited by ZD6474.
Conclusions: Long-term treatment of GEO xenografts with selective EGFR inhibitors results in the development of EGFR inhibitor-resistant
cancer cells. Growth of EGFR inhibitor-resistant tumors can be inhibited by ZD6474. These data indicate that inhibition of
VEGF signaling has potential as an anticancer strategy, even in tumors that are resistant to EGF inhibitors.
The transforming growth factor-α/epidermal growth factor receptor (TGF-α-EGFR) autocrine pathway, which is involved in the
development and the progression of human epithelial cancers, controls, in ...part, the production of angiogenic factors. These
angiogenic factors, including vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), are secreted
by cancer cells to stimulate normal endothelial cell growth through paracrine mechanisms. ZD1839 (Iressa) is a p.o.-active,
selective EGFR-tyrosine kinase inhibitor (TKI) in clinical trials in cancer patients. In this study, we evaluated the antiangiogenic
and antitumor activity of ZD1839 in human colon (GEO, SW480, and CaCo2), breast (ZR-75-1 and MCF-7 ADR), ovarian (OVCAR-3),
and gastric (KATO III and N87) cancer cells that coexpress TGF-α and EGFR. ZD1839 treatment determined a dose- and time-dependent
growth inhibition accompanied by the decrease of VEGF, bFGF and TGF-α production in vitro . Treatment of immunodeficient mice bearing well-established, palpable GEO xenografts with ZD1839 determined a cytostatic
dose-dependent tumor growth inhibition. Immunohistochemical analysis of GEO tumor xenografts after ZD1839 treatment revealed
a significant dose-dependent reduction of TGF-α, bFGF, and VEGF expression in cancer cells and of neoangiogenesis, as determined
by microvessel count. Furthermore, the antitumor activity of ZD1839 was potentiated in combination with the cytotoxic drug
paclitaxel in GEO tumor xenografts. Tumor regression was observed in all mice after treatment with ZD1839 plus paclitaxel,
and it was accompanied by a significant potentiation in inhibition of TGF-α, VEGF, and bFGF expression with a few or no microvessels.
Furthermore, 6 of 16 mice bearing well-established, palpable GEO xenografts had no histological evidence of GEO tumors at
the end of treatment with ZD1839 plus paclitaxel. These results demonstrate that the antitumor effect of ZD1839 is accompanied
by inhibition in the production of autocrine and paracrine growth factors that sustain autonomous local growth and facilitate
angiogenesis, and that this effect can be potentiated by the combined treatment with certain cytotoxic drugs, such as paclitaxel.
Purpose: The epidermal growth factor receptor (EGFR) is expressed in the majority of human epithelial cancers and has been implicated
in the development of cancer cell resistance to cyotoxic drugs ...and to ionizing radiation.
Experimental Design: We used ZD1839, a selective small molecule EGFR tyrosine kinase inhibitor currently in clinical development. We tested the
antiproliferative and the proapoptotic activity of ZD1839 in combination with ionizing radiation in human colon (GEO), ovarian
(OVCAR-3), non-small cell lung (A549 and Calu-6), and breast (MCF-7 ADR) cancer cell lines. The antitumor activity of this
combination was also tested in nude mice bearing established GEO colon cancer xenografts.
Results: With ionizing radiation or ZD1839, a dose-dependent growth inhibition was observed in all of the cancer cell lines growing
in soft agar. A cooperative antiproliferative and proapoptotic effect was obtained when cancer cells were treated with ionizing
radiation followed by ZD1839. This effect was accompanied by inhibition in the expression of the antiapoptotic proteins bcl-xL
and bcl-2, and by a suppression of the activated (phosphorylated) form of akt protein. Treatment of mice bearing established
human GEO colon cancer xenografts with radiotherapy (RT) resulted in a dose-dependent tumor growth inhibition that was reversible
upon treatment cessation. Long term GEO tumor growth regressions were obtained after RT in combination with ZD1839. This resulted
in a significant improvement in survival of these mice as compared with the control group ( P < 0.001), the RT-treated group ( P < 0.001), or the ZD1839-treated group ( P < 0.001). The only mice alive 10 weeks after tumor cell injection were in the RT-plus-ZD1839 group. Furthermore, 10% of mice
in this group were alive and tumor-free after 26 weeks. Similar results were obtained in mice bearing established human A549
lung adenocarcinoma xenografts. Finally, the combined treatment with RT plus ZD1839 was accompanied by a significant potentiation
in the inhibition of transforming growth factor α, vascular epidermal growth factor, and basic fibroblast growth factor expression
in cancer cells, which resulted in significant antiangiogenic effects as determined by immunohistochemical count of neovessels
within the GEO tumors.
Conclusion: This study provides a rationale for evaluating in cancer patients the combination of ionizing radiation and selective EGFR
tyrosine kinase inhibitors such as ZD1839.
Background
Assessment of hydration status is complex and difficult to detect in older persons. Different methods have been developed to determine hydration status in clinical settings, but their ...diagnostic accuracy remains questionable.
Aims
The aim of this study was to determine and compare the diagnostic accuracy of all methods routinely used in acute settings to detect dehydration in a cohort of hospitalized oldest-old persons, using as primary reference standard blood urea nitrogen (BUN) to creatinine ratio.
Methods
This retrospective study was conducted on 59 oldest-old subjects at hospital admission in an acute setting, with complete physical, biochemical, bioelectrical impedance analysis (BIA) and ultrasound assessment, including inferior vena cava diameters.
Results
Fifty-nine (45 women/14 men) subjects, with a mean age of 87.4 ± 5.9 years, were studied. Based on the value of the BUN/creatinine ratio, the whole population was divided into hyperhydrated (
n
= 10), normohydrated (
n
= 42), and dehydrated (
n
= 7) groups. Among parameters indicating the hydration status, serum sodium levels (
p
< 0.0001), serum chloride levels (
p
= 0.010), calculated plasma osmolarity (
p
< 0.0001), and fat mass (FM) (
p
= 0.030) differed significantly among groups. A ROC analysis showed that the highest and most significant value for dehydration detection was the calculated plasma osmolarity (AUC: 0.820,
p
= 0.013), which significantly correlated with clinical parameters including heart rate (
r
= 0.300;
p
= 0.021), capillary refill (
r
= 0.379;
p
= 0.013) and systolic blood pressure (
r
= − 0.261;
p
= 0.046).
Discussion
The measurement of calculated serum osmolarity is simple and inexpensive and may quickly provide high sensitivity and specificity indication of dehydration in hospitalized oldest-old persons.
Angiogenesis
plays a key role in tumor growth and metastasis. The transforming
growth factor α (TGF-α)-epidermal growth factor receptor (EGFR)
autocrine pathway controls in part the production of ...angiogenic factors
such as vascular endothelial growth factor (VEGF) and basic fibroblast
growth factor (bFGF) in cancer cells. In this study, we have evaluated
the antiangiogenic and antitumor activity of monoclonal antibody (MAb)
C225, an anti-EGFR chimeric human-mouse MAb, alone and in combination
with a human VEGF antisense (AS) 21-mer phosphorothioate
oligonucleotide (VEGF-AS) in human GEO colon cancer cells. MAb C225
treatment determined a dose-dependent inhibition of VEGF, bFGF, and
TGF-α production by GEO cells in vitro . Treatment with
VEGF-AS caused a selective inhibition in VEGF expression by GEO cells
in vitro . Treatment of immunodeficient mice bearing
established, palpable GEO xenografts for 3 weeks with VEGF-AS or with
MAb C225 determined a cytostatic reversible inhibition of tumor growth.
In contrast, a prolonged inhibition of tumor growth was observed in all
mice treated with the two agents, in combination with a
significant improvement in mice survival compared with controls
( P < .001), to MAb C225 ( P <
.001), or to VEGF-AS ( P < .001) treated mice. All
mice died within 4, 6, and 8 weeks after tumor cell injection in the
control, VEGF-AS and MAb C225 groups, respectively. In contrast, 50%
of mice treated with the combination of VEGF-AS and MAb C225 were alive
at 13 weeks. Ten % of mice treated with VEGF-AS plus MAb C225 were
alive at 20 weeks and had no histological evidence of GEO tumors.
Immunohistochemical analysis of GEO tumor xenografts demonstrated a
significant reduction of VEGF expression after treatment with VEGF-AS
with a parallel reduction in microvessel count. MAb C225 treatment
determined a reduction in the expression of VEGF, bFGF, and TGF-α
with a reduction in microvessel count. Finally, a significant
potentiation in inhibition of VEGF expression and little or no
microvessels were observed in GEO tumors after the combined treatment
with the two agents.
The aim of the study was to assess the toxicity and the clinical activity of biweekly oxaliplatin in combination with infusional 5-fluorouracil (5-FU) and folinic acid (FA) administered every 2 weeks ...(FOLFOX-4 regimen) in patients with advanced gastric cancer (AGC). A total of 61 previously untreated AGC patients were treated with oxaliplatin 85 mg m(-2) on day 1, FA 200 mg m(-2) as a 2 h infusion followed by bolus 5-FU 400 mg m(-2) and a 22 h infusion of 5-FU 600 mg m(-2), repeated for 2 consecutive days every 2 weeks. All patients were assessable for toxicity and response to treatment. Four (7%) complete responses and 19 partial responses were observed (overall response rate, 38%). Stable disease was observed in 22 (36%) patients, with progressive disease in the other six (10%) patients. Median time to progression (TTP) and median overall survival (OS) were 7.1 and 11.2 months, respectively. National Cancer Institute Common Toxicity Criteria grade 3 and 4 haematologic toxicities were neutropenia, anaemia and thrombocytopenia in 36, 10 and 5% of the patients, respectively. Grade 3 peripheral neuropathy was recorded in three (5%) patients. FOLFOX-4 is an active and well-tolerated chemotherapy. Response rate (RR), TTP and OS were comparable with those of other oxaliplatin-based regimens, suggesting a role for this combination in gastric cancer.
Purpose: Experimental data suggest a complex cross-talk between HER-2 and estrogen receptor, and it has been hypothesized that HER-2-positive
tumors may be less responsive to certain endocrine ...treatments. Clinical data, however, have been conflicting. We have conducted
a meta-analysis on the interaction between the response to endocrine treatment and the overexpression of HER-2 in metastatic
breast cancer.
Experimental Design: Studies have been identified by searching the Medline, Embase, and American Society of Clinical Oncology abstract databases.
Selection criteria were ( a ) metastatic breast cancer, ( b ) endocrine therapy (any line of treatment), and ( c ) evaluation of HER-2 expression (any method). For each study, the relative risk for treatment failure for HER-2-positive
over HER-2-negative patients with 95% confidence interval was calculated as an estimate of the predictive effect of HER-2.
Pooled estimates of the relative risk were computed by the Mantel-Haenszel method.
Results: Twelve studies ( n = 2,379 patients) were included in the meta-analysis. The overall relative risk was 1.42 (95% confidence interval, 1.32-1.52;
P < 0.00001; test for heterogeneity = 0.380). For studies involving tamoxifen, the pooled relative risk was 1.33 (95% confidence
interval, 1.20-1.48; P < 0.00001; test for heterogeneity = 0.97); for studies involving other hormonal drugs, a pooled relative risk of 1.49 (95%
confidence interval, 1.36-1.64; P < 0.00001; test for heterogeneity = 0.08) was estimated. A second meta-analysis limited to tumors that were either estrogen
receptor positive, estrogen receptor unknown, or estrogen receptor negative/progesterone receptor positive yielded comparable
results.
Conclusions: HER-2-positive metastatic breast cancer is less responsive to any type of endocrine treatment. This effect holds in the subgroup
of patients with positive or unknown steroid receptors.
Purpose: Vascular endothelial growth factor (VEGF) is a major mitogen for endothelial cells and enhances vascular permeability. Enhanced
VEGF secretion is found in human cancers and correlates with ...increased tumor neovascularization. ZD6474 is a p.o. bioavailable,
VEGF flk-1/KDR receptor (VEGFR-2) tyrosine kinase inhibitor with antitumor activity in many human cancer xenografts and is
currently in Phase I clinical development.
Experimental Design: We tested the effects of ZD6474 on EGFR phosphorylation in cell expressing functional epidermal growth factor receptor (EGFR)
and the antiproliferative and the proapoptotic activity of ZD6474 alone or in combination taxanes in human cancer cell lines
with functional EGFR but lacking VEGFR-2. The antitumor activity of this drug was also tested in nude mice bearing established
GEO colon cancer xenografts.
Results: ZD6474 causes a dose-dependent inhibition of EGFR phosphorylation in mouse NIH-EGFR fibroblasts and human MCF-10A ras breast
cancer cells, two cell lines that overexpress the human EGFR. ZD6474 treatment resulted in a dose-dependent inhibition of
soft agar growth in seven human cell lines (breast, colon, gastric, and ovarian) with functional EGFR but lacking VEGFR-2.
A dose-dependent supra-additive effect in growth inhibition and in apoptosis in vitro was observed by the combined treatment with ZD6474 and paclitaxel or docetaxel. ZD6474 treatment of nude mice bearing palpable
GEO colon cancer xenografts (which are sensitive to inhibition of EGFR signaling) induced dose-dependent tumor growth inhibition.
Immunohistochemical analysis revealed a significant dose-dependent reduction of neoangiogenesis. The antitumor activity of
ZD6474 in GEO tumor xenografts was also found to be enhanced when combined with paclitaxel. Tumor regression was observed
in all mice after treatment with ZD6474 plus paclitaxel, and it was accompanied by a significant potentiation in inhibition
of angiogenesis. Six of 20 mice had no histological evidence of tumors after treatment with ZD6474 plus paclitaxel.
Conclusions: This study suggests that in addition to inhibiting endothelial cell proliferation by blocking VEGF-induced signaling, ZD6474
may also be able to inhibit cancer cell growth by blocking EGFR autocrine signaling. These results provide also a rationale
for the clinical evaluation of ZD6474 combined with taxanes in cancer patients.
Purpose: The transforming growth factor α-epidermal growth factor receptor (EGFR) autocrine pathway has been implicated in prostate
cancer cell growth. Amplification and/or overexpression of ...c-erbB-2, a receptor closely related to the EGFR, has been recently
involved in prostate cancer progression. We investigated EGFR and c-erbB-2 expression in primary androgen-dependent and in
advanced androgen-independent prostate cancer and their potential role as markers of disease progression.
Experimental Design: EGFR and c-erbB-2 expression were evaluated by immunohistochemistry in a consecutive series of 74 prostate cancer patients
with the following characteristics: 29 patients (group 1) treated with radical prostatectomy; 29 patients (group 2) treated
with luteinizing hormone-releasing hormone analogues and antiandrogen therapy followed by radical prostatectomy; and 16 patients
with hormone-refractory metastatic disease. In all patients we evaluated: association between EGFR and/or c-erbB-2 expression
and clinicopathological parameters; and disease-free survival according to EGFR and c-erbB-2 expression in univariate analysis
(Kaplan-Meier product-limit method) and in multivariate analysis (Cox proportional hazards regression model).
Results: EGFR expression was found in 12 of 29 (41.4%) group 1 patients, in 22 of 29 (75.9%) group 2 patients ( P < 0.0005), and in 16 of 16 (100%) metastatic patients ( P < 0.005), whereas c-erbB-2 expression was found in 11 of 29 (37.9%) group 1, in 10 of 29 (34.5%) group 2 patients, and in
9 of 16 (56.3%) metastatic patients. A significant association was found between EGFR expression and a high Gleason score
( P < 0.01) and between EGFR expression and higher serum prostate-specific antigen values ( P < 0.02) in all groups of patients. Among the 58 patients treated with radical prostatectomy, 23 of 34 EGFR-positive patients
(67.6%) relapsed, whereas only 2 of 24 EGFR-negative patients (8.3%) relapsed ( P < 0.00004). c-erbB-2 expression did not significantly correlate with disease relapse ( P = 0.07). In a Cox multivariate analysis, the only parameter with an independent prognostic effect on disease-free survival
was EGFR expression (relative hazard, 11.23; P = 0.0014).
Conclusions: EGFR expression increases during the natural history of prostate cancer. Correlation with disease progression and hormone-refractory
disease suggests that EGFR-targeted drugs could be of therapeutic relevance in prostate cancer.
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