Higher baseline TSH levels predict early hypothyroidism during cancer immunotherapy.

BACKGROUND AND PURPOSE: Immune checkpoint inhibitors (ICIs) are monoclonal antibodies that enhance the immune response against cancer cells. ICIs are generally well tolerated, although endocrine immune-related adverse events (irAEs) are common. We investigated the risk factors for thyroid irAEs in patients treated with ICIs. Moreover, we evaluated the clinical outcome of subjects who became hypothyroid compared to euthyroid patients. PATIENTS AND METHODS: We retrospectively analyzed a series of 195 consecutively subjects treated with ICIs for metastatic tumors at the University of Naples "Federico II" between January 2014 and March 2020. Only subjects tested for thyroid function before and during the treatment with ICIs were included. RESULTS: In the 96 patients treated with ICIs who were included [66 males, median age: 62 years (27-87)], thyroid irAEs occurred in 36 (37.5%), 16 (16.7%) a transient thyrotoxicosis, and 20 (20.8%) an hypothyroidism (in nine subjects hypothyroidism was preceded by a transient thyrotoxicosis). Only baseline TSH levels above 1.67 mIU/L and positive anti-thyroid antibodies (Ab-T) were associated with a higher risk of hypothyroidism. Patients with hypothyroidism during ICI treatment showed an improved 2-year PFS (HR = 0.82 CI 0.47-1.43; p = 0.0132) and OS (HR = 0.38 CI 95% 0.17-0.80; p = 0.011) compared to euthyroid patients. CONCLUSIONS: Baseline TSH levels above 1.67 mIU/L and presence of Ab-T are risk factors for the development of thyroid irAEs. Patients affected by thyroid irAEs showed a longer survival than patients who remained euthyroid.

Angiogenic and signalling proteins correlate with sensitivity to sequential treatment in renal cell cancer.

BACKGROUND: We aimed to study key signalling proteins involved in angiogenesis and proliferation on the response to inhibitors of tyrosine kinases and mammalian target of rapamycin in first- and in second-line treatment of renal cell carcinoma (RCC). METHODS: In a panel of human RCC tumours, in vitro and in nude mice, we evaluated the effect of sunitinib, sorafenib and everolimus, alone and in sequence, on tumour growth and expression of signalling proteins involved in proliferation and resistance to treatment. RESULTS: We demonstrated that, as single agents, sunitinib, sorafenib and everolimus share similar activity in inhibiting cell proliferation, signal transduction and vascular endothelial growth factor (VEGF) secretion in different RCC models, both in vitro and in tumour xenografts. Pre-treatment with sunitinib reduced the response to subsequent sunitinib and sorafenib but not to everolimus. Inability by sunitinib to persistently inhibit HIF-1, VEGF and pMAPK anticipated treatment resistance in xenografted tumours. After first-line sunitinib, second-line treatment with everolimus was more effective than either sorafenib or rechallenge with sunitinib in interfering with signalling proteins, VEGF and interleukin-8, translating into a significant advantage in tumour growth inhibition and mice survival. CONCLUSION: We demonstrated that a panel of angiogenic and signalling proteins can correlate with the onset of resistance to sunitinib and the activity of everolimus in second line.

Toll-like receptor 9 agonist IMO cooperates with everolimus in renal cell carcinoma by interfering with tumour growth and angiogenesis.

BACKGROUND: Targeting the mammalian target of rapamycin by everolimus is a successful approach for renal cell carcinoma (RCC) therapy. The Toll-like receptor 9 agonist immune modulatory oligonucleotide (IMO) exhibits direct antitumour and antiangiogenic activity and cooperates with both epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF) inhibitors. METHODS: We tested the combination of IMO and everolimus on models of human RCC with different Von-Hippel Lindau (VHL) gene status, both in vitro and in nude mice. We studied their direct antiangiogenic effects on human umbilical vein endothelial cells. RESULTS: Both IMO and everolimus inhibited in vitro growth and survival of RCC cell lines, and their combination produced a synergistic inhibitory effect. Moreover, everolimus plus IMO interfered with EGFR-dependent signaling and reduced VEGF secretion in both VHL wild-type and mutant cells. In RCC tumour xenografts, IMO plus everolimus caused a potent and long-lasting cooperative antitumour activity, with reduction of tumour growth, prolongation of mice survival and inhibition of signal transduction. Furthermore, IMO and everolimus impaired the main endothelial cell functions. CONCLUSION: A combined treatment with everolimus and IMO is effective in VHL wild-type and mutant models of RCC by interfering with tumour growth and angiogenesis, thus representing a potentially effective, rationale-based combination to be translated in the clinical setting.

Two novel human anti-ErbB2 immunoagents are active on trastuzumab-resistant tumours.

BACKGROUND: Overexpression of ErbB2 receptor in breast cancer is associated with disease progression and poor prognosis. Trastuzumab, the only humanised anti-ErbB2 antibody currently used in breast cancer, has proven to be effective; however, a relevant problem for clinical practice is that a high fraction of breast cancer patients shows primary or acquired resistance to trastuzumab treatment. METHODS: We tested on trastuzumab-resistant cells two novel human anti-tumour immunoconjugates engineered in our laboratory by fusion of a human anti-ErbB2 scFv, termed Erbicin, with either a human RNase or the Fc region of a human IgG1. Both Erbicin-derived immunoagents (EDIAs) are selectively cytotoxic for ErbB2-positive cancer cells in vitro and vivo, target an ErbB2 epitope different from that recognised by trastuzumab and do not show cardiotoxic effects. RESULTS: We report that EDIAs are active also on trastuzumab-resistant tumour cells both in vitro and in vivo, most likely because of the different epitope recognised, as EDIAs, unlike trastuzumab, were found to be able to inhibit the signalling pathway downstream of ErbB2. CONCLUSION: These results suggest that EDIAs are immunoagents that could not only fulfil the therapeutic need of patients ineligible to trastuzumab treatment due to cardiac dysfunction but also prove to be useful for breast cancer patients unresponsive to trastuzumab treatment.

Paraneoplastic sensitive neuropathy associated with anti-hu antibodies in a neuroendocrine tumor of duodenum: a case report.

Paraneoplastic sensitive neuropathy is one of the most common presentations among a group of cancer-related disorders known as Paraneoplastic Neurological Syndromes (PNS). PNS likely have an autoimmune etiology since they have been associated with the presence of antibodies against neuronal antigens expressed by tumor cells (such as anti-Hu, anti-Ri and anti-Yo). The tumors most frequently associated with PSN and onconeural antibodies are lung cancer, lymphomas and gynaecological tumors; however, they have also been described in other tumors. We report, for the first time, a case of neuroendocrine tumor of duodenum and PNS associated with anti-Hu antibodies. Moreover, we analyze and discuss the clinical implications that PNS and anti-Hu could have in patients with tumors.

Is hypogammaglobulinemia a constant feature in Good's syndrome?

Thymomas are rare tumors, which can be associated to a variety of paraneoplastic syndromes, including a fatal hypogammaglobulinemia, namely Good?s Syndrome (GS). Although the combination of thymoma and hypogammaglobulinemia is regarded as sufficient for diagnosis of Good?s syndrome, some thymoma patients with a clear clinical picture of immunodeficiency present normal levels of immunoglobulins. We describe the case of a patient, with a 20-year history of thymoma, who underwent several operations and lines of chemotherapy, and suffered from recurrent infections, including one rare skin infection from Pseudoallescheria boydii. The patient constantly presented normal levels of gammaglobulins.

Scleroderma and the subcutaneous tissue.

Our study revealed that as observed with both light and electron microscopy the most specific abnormality in sclerodermna skin is the replacement of the subcutaneous tissue by markedly abnormal connective tissue.

Enzastaurin inhibits tumours sensitive and resistant to anti-EGFR drugs.

We investigated the antitumour effect and ability to overcome the resistance to anti-EGFR drugs of enzastaurin, an inhibitor of VEGFR-dependent PKCbeta signalling. Enzastaurin was evaluated alone and in combination with the EGFR inhibitor gefitinib, on growth and signalling protein expression in human cancer cells sensitive and resistant to anti-EGFR drugs, both in vitro and in nude mice. We demonstrated the marked inhibitory activity of enzastaurin against GEO colon and PC3 prostate cancer cells and their gefitinib-resistant counterparts GEO-GR and PC3-GR, accompanied by inhibition of pAkt and its effector pp70S6K, pGSK3beta and VEGF expression and secretion. Moreover, enzastaurin showed a cooperative effect with gefitinib in parental and in gefitinib-resistant cells. Remarkably, these results were confirmed in vivo, where enzastaurin showed antitumour activity and cooperativity with gefitinib in mice grafted with GEO and GEO-GR tumours, incrementing their median survival and inhibiting the aforesaid protein expression and secretion in tumour specimens. In conclusion, enzastaurin by interfering with signalling proteins implicated in EGFR drug resistance markedly cooperates with gefitinib in sensitive and gefitinib-resistant tumours, thus overcoming and reverting such resistance and providing a rational basis for its development in patients resistant to anti-EGFR drugs.

A model of decreased functional alpha-1-proteinase inhibitor. Pulmonary pathology of dogs exposed to chloramine T.

The objective of this study was to develop an animal model representative of chronic human alpha-1-proteinase inhibitor deficiency. Eight dogs were treated with a mild oxidizing agent, chloramine T, with varying regimens for 3--27 wk. The capacity of the serum to inhibit both trypsin and elastase was examined and found to respond differently. Although immunologically determined levels of protease inhibitor did not change, the ability of serum to inhibit elastase in an in vitro assay decreased in direct response to chloramine T treatment. The trypsin inhibitory capacity was less affected. Emphysemalike alterations in lung morphology were observable when histologic sections were evaluated both subjectively and objectively by mean linear intercept measurements. The data suggest that this model parallels the emphysema associated with the genetic alpha-1-proteinase inhibitor deficiency in man.

Immunolocalization of elastase in human emphysematous lungs.

The current working hypothesis concerning the pathogenesis of human pulmonary emphysema proposes that neutrophils migrate through the alveolar interstitium and degranulate, releasing proteolytic enzymes into the interstitium. These enzymes, in particular elastase, can bind to and degrade interstitial elastin. This report describes an immunohistochemical, ultrastructural technique that utilizes polyclonal antibodies to localize neutrophil elastase in human lungs. Using both the immunoperoxidase and the immunogold methods on thin, embedded sections of surgically resected human emphysematous lung tissue, elastase was localized in neutrophils in the lung interstitium and extracellularly in association with interstitial elastic fibers in human lungs that showed local emphysema of varying severity. Quantitative morphometric data were obtained from the lungs of eight patients undergoing lobectomy for removal of pulmonary carcinomas. Patients had preoperative forced expiratory volume (FEV1)% levels ranging from 55 to 77. There was a correlation between a quantitative measure of the local distribution of neutrophil elastase in contact with alveolar interstitial elastin and the local presence of emphysematous change as determined by mean linear intercept of the various histologic sections. These data support the validity of the "protease-protease inhibitor balance hypothesis" as an explanation of the pathogenesis of human pulmonary emphysema.

Predictors of Asymptomatic Radiation-induced Abdominal Atherosclerosis.

AIMS: To identify predictors of asymptomatic radiation-induced abdominal atherosclerosis in patients treated with radiotherapy and evaluated by abdominal vascular ultrasonography. MATERIALS AND METHODS: Forty-two testicular classic seminoma patients (median age 34 years, range 16-56) undergoing radical inguinal orchiectomy were analysed. Twenty-six patients underwent post-surgery radiotherapy (median total dose 25 Gy, range 25-43), two of them also received chemotherapy (CHT) and 16 patients were treated with surgery alone or by surgery followed by CHT (control group). The presence of stenosis in an abdominal vessel and renal resistive index (RRI), evaluated by echo-colour Doppler (ECD), were considered as indicators of late vascular damage. Chi-square and Mann-Whitney tests were used to compare groups. For the radiotherapy group, near maximum (D2%) and mean dose (Dmean) metrics of critical structures (abdominal arteries and renal hila) were extracted from retrievable dose maps (18 of 26 radiotherapy patients). To evaluate clinical and dosimetric factors associated with vascular damage, univariate and multivariate analyses were carried out. The impact of dose to arteries, evaluated as separate subvolumes, was analysed comparing the stenotic arteries with normal ones by logistic regression. The area under the receiver operator characteristic curve (AUC) was used to evaluate the test accuracy. RESULTS: In the radiotherapy group there was a significantly different incidence of stenosis (31% versus 0%, P = 0.016) and a higher median average RRI (0.63 versus 0.60, P = 0.032) compared with the control group. The median time intervals between treatment and ECD were 64 months (range 12-120) and 48 months (range 12-168) in the radiotherapy and control groups (P = 0.399), respectively. A younger age at radiotherapy was the only clinical risk factor for stenosis (P = 0.006). Artery Dmean was significantly associated with stenosis (P = 0.008), with an odds ratio of 1.13 (95% confidence interval 1.01-1.26) and an AUC of 0.85 (95% confidence interval 0.77-0.91). Renal hilum D2% was correlated with RRI (Rs = 0.406, P = 0.02). CONCLUSIONS: Late vascular damage represents a potential effect of abdominal radiotherapy, even at a moderate dose. Younger age at irradiation, artery and renal hila dose metrics are associated with increased risk. Ultrasound-based follow-up may allow for non-invasive early detection of asymptomatic radiation-induced damage, helping to prevent severe vascular events.

Antitumor activity of combined blockade of epidermal growth factor receptor and protein kinase A.

BACKGROUND: Epidermal growth factor (EGF)-related proteins, such as transforming growth factor-alpha (TGF-alpha), control cancer cell growth through hormonal pathways (i.e., autocrine [hormone acts on cell that produces it] and paracrine [hormone acts on nearby cells] pathways). Overexpression of TGF-alpha and/or its receptor (EGFR) has been detected in human cancers. The blockade of EGFR activation by the use of anti-EGFR monoclonal antibodies (MAbs) has been proposed as a potential anticancer therapy. The type I cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKAI) is generally overexpressed in human cancer cells and is involved in neoplastic transformation. Inhibition of PKAI by selective cAMP analogues, such as 8-chloro-cAMP (8-CI-cAMP), induces growth inhibition in various human cancer cell lines. PURPOSE: On the basis of our previous observations of a cooperative anti-proliferative effect of anti-EGFR Mab 528 and 8-Cl-cAMP in human cancer cell lines in vitro, we evaluated the anticancer activity in vivo of the combination of an anti-EGFR MAb (MAb C225) and 8-Cl-cAMP. METHODS: Athymic mice were injected subcutaneously with 10(7) human colon carcinoma GEO cells. After 7 days, when established tumor xenografts of 0.30-0.35 cm3 were detectable, 10-15 mice per group were treated intraperitoneally twice weekly with different doses of 8-Cl-cAMP and/or MAb C225. Cancer cell expression of various growth factors was evaluated by immunohistochemical analysis in tumors obtained from control and treated mice. Data were evaluated for statistical significance using the Student's t test and the Mantel-Cox logrank test. All P values represent two-sided tests of statistical significance. RESULTS: A 5-week treatment with low doses of 8-Cl-cAMP (0.5 mg/dose) and MAb C225 (0.25 mg/dose) blocked GEO tumor growth (compared with that in control mice; P < .00001) and suppressed cancer cell production of autocrine growth factors, such as TGF-alpha, amphiregulin, and CRIPTO, and of angiogenic (promotes new blood vessel formation) factors, such as vascular endothelial growth factor and basic fibroblast growth factor, with no signs of toxicity. Control and 8-Cl-cAMP (0.5 mg/dose)-treated mice died within 9-10 weeks after tumor cell injection. In MAb C225 (0.25 mg/dose)-treated mice, GEO tumors resumed a growth rate comparable to that in control animals within 3 weeks following the end of treatment and the mice died between 11 and 20 weeks after tumor cell injection. GEO tumor growth was significantly delayed in the MAb C225 plus 8-Cl-cAMP treatment group (P < .00001) and was accompanied by a prolonged survival of mice (P < .00001) as compared with the control group. CONCLUSIONS: Long-term treatment with a combination of agents that selectively inhibit two intracellular signal-transduction enzymes, such as the PKAI serine-threonine kinase and the EGFR tyrosine kinase, has anticancer activity in vivo, reflected by suppression of tumor proliferation and angiogenesis, with no signs of toxicity. IMPLICATIONS: Since these inhibitors of intracellular mitogenic (growth-stimulating) signaling have a different mechanism(s) of action and do not antagonize the effects of cytotoxic therapy, a combination of anti-EGFR MAb C225 and 8-Cl-cAMP should be investigated as a nontoxic, long-term treatment for cancer patients following chemotherapy.

Cooperative inhibition of renal cancer growth by anti-epidermal growth factor receptor antibody and protein kinase A antisense oligonucleotide.

BACKGROUND: The expression of epidermal growth factor receptor (EGFR) and type I cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKAI) is associated with neoplastic transformation. By use of human renal cancer cell lines (i.e., 769-P, ACHN, A498, and SW839), we investigated the antiproliferative activity and the antitumor activity of an anti-EGFR humanized chimeric mouse monoclonal antibody, MAb C225, and a novel mixed backbone 18-mer antisense oligonucleotide, HYB 190, that targets expression of the RIalpha regulatory subunit of PKAI. METHODS: The antiproliferative activity of MAb C225 and oligonucleotide HYB 190, alone or in combination, on different renal cancer cell lines was determined by monitoring cell growth in soft agar. In addition, the induction of apoptosis by treatment with the anti-EGFR antibody and/or antisense PKAI oligonucleotides was evaluated by flow cytometric analysis of fragmented DNA. The antitumor activity of MAb C225 and oligonucleotide HYB 190 was determined in athymic mice bearing established ACHN tumor xenografts. Cell proliferation and tumor growth data were evaluated for statistical significance using Student's t test; reported P values are two-sided. RESULTS: MAb C225 and oligonucleotide HYB 190 inhibited colony formation in soft agar in a dose-dependent manner for all renal cancer cell lines tested. We observed a potentiation of growth inhibition and induction of apoptosis when 769-P cells and ACHN cells were treated with both agents. Combination treatment with MAb C225 and oligonucleotide HYB 190 caused regression of ACHN tumor xenografts, whereas single-agent treatment only delayed tumor growth. CONCLUSION: The combination of anti-EGFR MAb C225 and ited cooperative antiproliferative effects and cooperative antitumor effects on EGFR and PKAI-expressing human renal cancer cell lines.

Overexpression of the RI alpha subunit of protein kinase A confers hypersensitivity to topoisomerase II inhibitors and 8-chloro-cyclic adenosine 3'5'-monophosphate in Chinese hamster ovary cells.

We have shown that a mutant derivative of Chinese hamster ovary CHO-K1 cells, ADR-5, which shows hypersensitivity to topoisomerase II (topo II)-inhibitory drugs, is cross-sensitive to the site-selective cyclic AMP analogue 8-chloro-cyclic AMP. We tested the hypothesis that overexpression of the type I alpha regulatory subunit of protein kinase A may represent a common element conferring hypersensitivity to both topo II inhibitors and 8-chloro-cyclic AMP in ADR-5 cells. We have demonstrated that ADR-5 cells overexpress RI alpha protein, compared to parental CHO-K1 cells. Moreover, retroviral vector-mediated transfer of the RI alpha gene into CHO-K1 cells was able to confer a drug-hypersensitive phenotype similar to that exhibited by ADR-5 cells. Analysis of topo II protein levels and activity revealed no differences between parental and infected cells, suggesting that protein kinase A may be involved in the downstream processing of topo II-mediated events.

The RIalpha subunit of protein kinase A (PKA) binds to Grb2 and allows PKA interaction with the activated EGF-receptor.

Functional interactions between protein kinase A (PKA) and epidermal growth factor receptor (EGF-R) signalling pathways have been suggested. Unlike the type II isoform of PKA (PKAII), the type I (PKAI) and/or its regulatory subunit RIalpha are generally overexpressed in cancer cells and are induced following transforming growth factor alpha (TGF alpha)/EGF-R-dependent transformation. Downregulation of RIalpha/PKAI inhibits TGF alpha expression and EGF-R-dependent signalling. We have previously shown that addition of EGF to quiescent human normal epithelial MCF-10A cells determines PKAI expression and cell membrane translocation before cells enter S phase, while PKAI inhibition prevents S phase entry. Constitutive overexpression of PKAI confers the ability to grow in serum free medium, bypassing EGF requirement. Here we demonstrate a direct interaction of PKAI, but not of PKAII, with the activated EGF-R, that occurs within 5 min following EGF treatment of MCF-10A cells. Moreover, induction of mitogen-activated protein kinase (MAPK) activity following EGF-R activation is mimicked by PKAI overexpression and inhibited by downregulators of PKAI. Finally, the PKAI-EGF-R association occurs through the binding of RIalpha to the SH3 domain(s) of Grb2 adaptor protein, thus allowing the recruitment of the PKAI holoenzyme to the activated EGF-R. This is the first demonstration of a direct interaction of PKAI with the activated EGF-R macromolecular signalling complex.

Oral antisense that targets protein kinase A cooperates with taxol and inhibits tumor growth, angiogenesis, and growth factor production.

Protein kinase A type I (PKAI) transduces mitogenic signals from different growth factors and oncogenes and is overexpressed in the majority of human cancers. We and other investigators previously have reported that different PKAI inhibitors, including antisense oligonucleotides, have antitumor activity. In this study, we used a novel hybrid DNA/RNA mixed-backbone oligonucleotide (MBO) targeting the PKAI subunit RIalpha. We demonstrated that after oral administration, the MBO antisense RIalpha inhibited the growth of human colon cancer xenografts in nude mice and showed a cooperative antitumor effect with Taxol, which outlasted treatment withdrawal and significantly prolonged survival of mice compared with untreated controls or to single-agent-treated mice. Immunohistochemical analysis of tumor specimens showed inhibition of target protein RIalpha and of growth factor expression along with a marked inhibition of angiogenesis and an increase in p27 expression. In conclusion, a novel MBO that targets PKAI, administered p.o., is effective and cooperates with the anticancer drug Taxol on both tumor growth and expression of factors involved in the control of cell proliferation, cell cycle, and angiogenesis. Because the MBO described has completed a phase I trial involving i.v. injection in cancer patients, these results provide the biological rationale of its activity after oral administration and may be translated into a therapeutic strategy in a clinical setting.

Combined blockade of protein kinase A and bcl-2 by antisense strategy induces apoptosis and inhibits tumor growth and angiogenesis.

Protein kinase A type I (PKAI) plays a key role in neoplastic transformation, conveys mitogenic signals from different sources, and is overexpressed in the majority of human tumors. Inhibition of PKAI by different tools results in cancer-cell growth inhibition in vitro and in vivo. We and others have recently shown that a novel class of mixed-backbone oligonucleotides targeting the PKAI subunit RIalpha exhibits improved pharmacokinetic properties and antitumor activity accompanied by increased apoptosis in several human cancer types in vitro and in vivo. The role of bcl-2 in the control of apoptosis has been widely documented, and the inhibition of bcl-2 expression and function may have important therapeutic implications. In fact, oligonucleotides antisense bcl-2 have shown antitumor activity in animal models and have successfully completed early clinical trials. Recent studies have demonstrated a direct role of PKA in the regulation of the bcl-2-dependent apoptotic pathway. Therefore, we have investigated the combined blockade of PKA and bcl-2 by antisense strategy as a potential therapeutic approach. The novel hybrid DNA/RNA mixed-backbone oligonucleotide antisense RIalpha (AS RIalpha) in combination with the antisense bcl-2 (AS bcl-2), cooperatively inhibited bcl-2 expression and soft agar growth and induced apoptosis in different human cancer cell lines. p.o. administration of AS RIalpha in combination with i.p. AS bcl-2 caused a marked antitumor effect and a significant prolongation of survival in nude mice bearing human colon cancer xenografts. Moreover, histochemical analysis of tumor specimens showed inhibition of RIalpha and Ki67 expression, inhibition of angiogenesis, and parallel induction of apoptosis in vivo. The results of our study imply an interaction between the PKA and bcl-2 signaling pathways and, because both antisenses have now entered Phase II trials, provide the rationale to translate this novel therapeutic strategy in a clinical setting.

Oral administration of a novel taxane, an antisense oligonucleotide targeting protein kinase A, and the epidermal growth factor receptor inhibitor Iressa causes cooperative antitumor and antiangiogenic activity.

PURPOSE: Protein kinase A type I (PKAI) and the epidermal growth factor receptor (EGFR) play a role in neoplastic transformation and interact with each other in transducing mitogenic signals. We developed different PKAI and EGFR inhibitors, demonstrating their cooperation with cytotoxic drugs and the therapeutic potential of the combined blockade of PKAI and EGFR. In this study, we investigated the effect of orally active PKAI and EGFR inhibitors in combination with a novel taxane. EXPERIMENTAL DESIGN: We combined a hybrid PKAI antisense oligonucleotide sequence (AS-PKAI), the EGFR inhibitor ZD1839 (Iressa), and the taxane IDN5109, studying their effect on human cancer growth, apoptosis, and angiogenesis and measuring vascular endothelial growth factor (VEGF) expression and vessel formation in vitro and after oral administration in nude mice. RESULTS: We demonstrated cooperative growth inhibitory and proapoptotic effects and inhibition of VEGF expression with any combination of two drugs and a marked synergistic effect when all three agents were combined. Oral administration of AS-PKAI, ZD1839, and IDN5109 in combination to nude mice caused a remarkable antitumor effect with no histological evidence of tumors in 50% of mice 5 weeks after treatment withdrawal, accompanied by complete suppression of vessel formation and VEGF expression. CONCLUSION: This is the first demonstration of the cooperative antitumor and antiangiogenic activity of three novel agents that block multiple signaling pathways after oral administration. Because all agents are under clinical evaluation in cancer patients, our results provide a rationale to translate this feasible therapeutic strategy in a clinical setting.

Antiangiogenic and antitumor activity of anti-epidermal growth factor receptor C225 monoclonal antibody in combination with vascular endothelial growth factor antisense oligonucleotide in human GEO colon cancer cells.

Angiogenesis plays a key role in tumor growth and metastasis. The transforming growth factor alpha (TGF-alpha)-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-alpha 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-alpha 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.

Antitumor effect and potentiation of cytotoxic drugs activity in human cancer cells by ZD-1839 (Iressa), an epidermal growth factor receptor-selective tyrosine kinase inhibitor.

Transforming growth factor alpha (TGF-alpha) is an autocrine growth factor for human cancer. Overexpression of TGF-alpha 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-alpha. 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.