Tito Fojo - Academia.edu (original) (raw)

Papers by Tito Fojo

JNCI Journal of the National Cancer Institute, 2008

The Common Terminology Criteria for Adverse Events (CTCAE), version 3.0, and its predecessors, th... more The Common Terminology Criteria for Adverse Events (CTCAE), version 3.0, and its predecessors, the Common Toxicity Criteria (CTC) versions 1.0 and 2.0, were developed under the direction of the Cancer Therapy Evaluation Program of the National Cancer Institute (NCI) in an effort to provide standard language for reporting adverse events that occur in NCI-sponsored clinical trials. Each successive version of the CTC has improved the accuracy, precision, and completeness of the criteria in an effort to standardize reporting. We believe that the current version of the CTCAE cannot adequately code the subacute adverse events that commonly occur with today's targeted therapies.

The Cancer Journal, 2013

Adrenocortical carcinoma (ACC) is a rare and highly malignant tumor usually diagnosed in an advan... more Adrenocortical carcinoma (ACC) is a rare and highly malignant tumor usually diagnosed in an advanced stage. Radiation therapy has been a poorly studied and underutilized therapeutic option. This retrospective analysis reviewed treatment courses for 14 patients with pathologically confirmed ACC treated between 1997 and 2012. Two patients were treated adjuvantly following surgery, and 12 were treated with palliative intent. Patients presented with stage II (n = 4), stage III (n = 7), and stage IV (n = 3) disease. Patients had a mean age of 51.5 years. Ten patients received chemotherapy before radiotherapy (RT), and 12 patients received surgery before RT, before receiving radiation at a mean of 17.8 months after diagnosis. In total, 20 sites were treated, 2 of which were in an adjuvant setting, and 18 of which were for palliative indications in 12 patients as follows: (1) pain/neuropathy (n = 10), (2) prophylactic treatment of asymptomatic recurrences (n = 3), and (3) prevention of imminent metastatic complications (n = 2), hemoptysis (n = 1), severe mass effect (n = 1), and brain metastasis (n = 1). Sites were treated to a median dose of 36.3 Gy (range, 17.5-60 Gy) in a median of 2.5 Gy/fraction (range, 1.8-4 Gy). At a mean follow-up of 22.0 months for the 2 patients given adjuvant RT, 1 patient did not have a local recurrence during a 14.3-month period of follow-up, and the other had a local recurrence 14.5 months after RT. At a mean follow-up of 11.3 months for the 12 patients receiving palliative RT, 10 patients had either a clinical or radiographic response. Of the courses of palliative RT that had adequate radiographic follow-up, 4 treatments (27%) resulted in a partial response. Eleven treatments (73%) that were able to be evaluated resulted in clinical improvement. Acute Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer toxicities observed in 7 patients included 3 grade 1, 4 grade 2, and 1 grade 3. No patient had acute toxicity of grade 4 or greater or any Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer late toxicity of grade 1 or greater. This report is one of the largest to date examining the role of modern radiation techniques in the management of ACC. We conclude that radiation can be effective in the management of metastatic ACC, palliating local symptoms, and preventing complications from large metastases. Radiation should be considered as an option in multimodality management of ACC patients.

Journal of clinical oncology : official journal of the American Society of Clinical Oncology, 2003

The epothilones are a novel class of nontaxane microtubule-stabilizing agents. BMS-247550 is a se... more The epothilones are a novel class of nontaxane microtubule-stabilizing agents. BMS-247550 is a semisynthetic analog of the natural product epothilone B. We conducted a phase I study administering BMS-247550 as a 1-hour intravenous infusion daily for 5 consecutive days every 21 days. Twenty-one patients received BMS-247550 without filgrastim in the first cycle. An additional six patients were enrolled at a starting dose of 8 mg/m2/d with filgrastim support. Twenty-one of the 27 patients had received prior paclitaxel, docetaxel, or both. One hundred seven cycles were administered to 27 patients. The maximum-tolerated dose was 6 mg/m2 of BMS-247550 administered as a 1-hour intravenous infusion daily for 5 consecutive days every 21 days. Dose-limiting toxicity at a dose of 8 mg/m2/d was neutropenia with or without filgrastim support. Nonhematologic grade 3 toxicities included fatigue (seven cycles), stomatitis (two cycles), and anorexia (one cycle). The mean terminal half-life of BMS-24...

The Journal of Clinical Endocrinology & Metabolism, 2014

Adrenocortical carcinoma (ACC) is a rare malignancy with a poor prognosis in need of more effecti... more Adrenocortical carcinoma (ACC) is a rare malignancy with a poor prognosis in need of more effective treatment options. Published evidence indicates many ACCs express the vascular endothelial growth factor receptor (VEGFR), suggesting inhibiting vascular endothelial growth factor signaling could potentially impact tumor growth. The objective of the study was to determine the antitumor efficacy of axitinib (AG-013736), a potent, selective inhibitor of VEGFR1, -2, and -3. This was a phase II, open-label trial using a two-stage design. Thirteen patients with metastatic ACC previously treated with at least one chemotherapy regimen with or without mitotane participated in the study. Starting axitinib dose was 5 mg orally twice daily. Dose escalations were permitted if the administered dose was tolerable. Thirteen patients were enrolled. Dose escalation was possible in seven patients, but the majority could not tolerate a dose higher than the starting 5 mg, twice-daily dose for prolonged periods of time. All patients experienced known grade 1/2 toxicities, and 10 of 13 patients had at least one grade 3/4 adverse event. No patient tumor could be scored as a Response Evaluation Criteria in Solid Tumors response, although the growth rate on therapy compared with that prior to starting axitinib was reduced in 4 of the 13 patients. The median progression-free survival was 5.48 months, and the median overall survival was longer than 13.7 months. Axitinib has limited effectiveness in ACC. Together with 48 patients previously reported who received either sorafenib or sunitinib, a total of 61 ACC patients have now been treated with a VEGFR tyrosine kinase inhibitor without an objective Response Evaluation Criteria in Solid Tumors response. Future trials in ACC should look to other targets for possible active agents.

The oncologist, Jan 3, 2015

Accrual to cervical cancer studies remains a puzzling challenge given the lack of options and the... more Accrual to cervical cancer studies remains a puzzling challenge given the lack of options and the dismal prognosis of this disease. The majority of patients referred for a trial such as this have very advanced disease that is difficult to manage.The observation of 4 partial responses among the 41 patients indicates that ixabepilone has some activity but not sufficient for further development without greater understanding of mechanisms of sensitivity and resistance. Ixabepilone is a microtubule-stabilizing agent approved for metastatic breast cancer. Preclinical data have shown that ixabepilone is active in taxane-sensitive and -resistant cells. Metastatic cervical carcinoma (mCC) has a poor prognosis and no established second-line therapies. This study assessed the efficacy and safety of ixabepilone in previously treated mCC. Patients with histologically confirmed mCC and at least one prior cisplatin-containing regimen were treated with ixabepilone [6 mg/m(2) per day for 5 days] eve...

The American Journal of Cardiology, 2015

Pheochromocytomas and paragangliomas are chromaffin cell tumors arising from neuroendocrine cells... more Pheochromocytomas and paragangliomas are chromaffin cell tumors arising from neuroendocrine cells. At least 1/3 of paragangliomas are related to germline mutations in 1 of 17 genes. Although these tumors can occur throughout the body, cardiac paragangliomas are very rare, accounting for <0.3% of mediastinal tumors. The purpose of this study was to determine the clinical characteristics of patients with cardiac paragangliomas, particularly focusing on their genetic backgrounds. A retrospective chart analysis of 15 patients with cardiac paragangliomas was performed to determine clinical presentation, genetic background, diagnostic workup, and outcomes. The average age at diagnosis was 41.9 years. Typical symptoms of paraganglioma (e.g., hypertension, sweating, palpitations, headache) were reported at initial presentation in 13 patients (86.7%); the remaining 2, as well as 4 symptomatic patients, initially presented with cardiac-specific symptoms (e.g., chest pain, dyspnea). Genetic testing was done in 13 patients (86.7%); 10 (76.9%) were positive for mutations in succinate dehydrogenase (SDHx) subunits B, C, or D. Thirteen patients (86.7%) underwent surgery to remove the paraganglioma with no intraoperative morbidity or mortality; 1 additional patient underwent surgical resection but experienced intraoperative complications after removal of the tumor due to co-morbidities and did not survive. SDHx mutations are known to be associated with mediastinal locations and malignant behavior of paragangliomas. In this report, the investigators extend the locations of predominantly SDHx-related paragangliomas to cardiac tumors. In conclusion, cardiac paragangliomas are frequently associated with underlying SDHx germline mutations, suggesting a need for genetic testing of all patients with this rare tumor.

The Journal of biological chemistry, Jan 4, 1997

Acquired resistance to paclitaxel can be mediated by P-glycoprotein or by alterations involving t... more Acquired resistance to paclitaxel can be mediated by P-glycoprotein or by alterations involving tubulin. We report two paclitaxel-resistant sublines derived from 1A9 human ovarian carcinoma cells. Single-step paclitaxel selection with verapamil yielded two clones that are resistant to paclitaxel and collaterally sensitive to vinblastine. The resistant sublines are not paclitaxel-dependent, and resistance remained stable after 3 years of drug-free culture. All cell lines accumulate [3H]paclitaxel equally, and no MDR-1 mRNA was detected by polymerase chain reaction following reverse transcription. Total tubulin content is similar, but the polymerized fraction increased in parental but not in resistant cells following the paclitaxel addition. Purified tubulin from parental cells demonstrated paclitaxel-driven increased polymerization, in contrast to resistant cell tubulin, which did not polymerize under identical conditions. In contrast, epothilone B, an agent to which the resistant ce...

Cancer research, 2014

Successful cancer treatments are generally defined as those that decrease tumor quantity. In many... more Successful cancer treatments are generally defined as those that decrease tumor quantity. In many cases, this decrease occurs exponentially, with deviations from a strict exponential being attributed to a growing fraction of drug-resistant cells. Deviations from an exponential decrease in tumor quantity can also be expected if drugs have a nonuniform spatial distribution inside the tumor, for example, because of interstitial pressure inside the tumor. Here, we examine theoretically different models of cell killing and analyze data from clinical trials based on these models. We show that the best description of clinical outcomes is by first-order kinetics with exponential decrease of tumor quantity. We analyzed the total tumor quantity in a diverse group of clinical trials with various cancers during the administration of different classes of anticancer agents and in all cases observed that the models that best fit the data describe the decrease of the sensitive tumor fraction expone...

Cancer research, Jan 15, 2003

Hemiasterlin is a natural product derived from marine sponges that, like other structurally diver... more Hemiasterlin is a natural product derived from marine sponges that, like other structurally diverse peptide-like molecules, binds to the Vinca-peptide site in tubulin, disrupts normal microtubule dynamics, and, at stoichiometric amounts, depolymerizes microtubules. Total synthesis of hemiasterlin and its analogues has been accomplished, and optimal pharmacological features of the series have been explored. The biological profile of one analogue, HTI-286, was studied here. HTI-286 inhibited the polymerization of purified tubulin, disrupted microtubule organization in cells, and induced mitotic arrest, as well as apoptosis. HTI-286 was a potent inhibitor of proliferation (mean IC(50) = 2.5 +/- 2.1 nM in 18 human tumor cell lines) and had substantially less interaction with multidrug resistance protein (P-glycoprotein) than currently used antimicrotubule agents, including paclitaxel, docetaxel, vinorelbine, or vinblastine. Resistance to HTI-286 was not detected in cells overexpressing ...

Molecular Therapy, 2005

Adenovirus gene therapy is frequently inefficient because of low levels of coxsackie adenovirus r... more Adenovirus gene therapy is frequently inefficient because of low levels of coxsackie adenovirus receptor (CAR) the primary adenovirus receptor. Previously, we showed that treatment of a diverse group of cancer cell lines with the histone deacetylase inhibitor FK228 (FR901228, depsipeptide), a drug in phase II clinical trials for the treatment of peripheral and cutaneous T-cell lymphoma, caused increases in CAR

JAMA Otolaryngology–Head & Neck Surgery, 2014

Cancer is expected to continue as a major health and economic problem worldwide. Several factors ... more Cancer is expected to continue as a major health and economic problem worldwide. Several factors are contributing to the increasing economic burden imposed by cancer, with the cost of cancer drugs an undeniably important variable. The use of expensive therapies with marginal benefits for their approved indications and for unproven indications is contributing to the rising cost of cancer care. We believe that expensive therapies are stifling progress by (1) encouraging enormous expenditures of time, money, and resources on marginal therapeutic indications and (2) promoting a me-too mentality that is stifling innovation and creativity. The modest gains of Food and Drug Administration-approved therapies and the limited progress against major cancers is evidence of a lowering of the efficacy bar that, together with high drug prices, has inadvertently incentivized the pursuit of marginal outcomes and a me-too mentality evidenced by the duplication of effort and redundant pharmaceutical pipelines. We discuss the economic realities that are driving this process and provide suggestions for radical changes to reengineer our collective cancer ecosystem to achieve better outcomes for society.

Molecular Cancer Therapeutics, 2007

Nature Reviews Cancer, 2005

The contribution of tumorigenic stem cells to haematopoietic cancers has been established for som... more The contribution of tumorigenic stem cells to haematopoietic cancers has been established for some time, and cells possessing stem-cell properties have been described in several solid tumours. Although chemotherapy kills most cells in a tumour, it is believed to leave tumour stem cells behind, which might be an important mechanism of resistance. For example, the ATP-binding cassette (ABC) drug transporters

The oncogenic protein Bcl-2 functions as a potent inhibitor of pro grammed cell death. This survi... more The oncogenic protein Bcl-2 functions as a potent inhibitor of pro grammed cell death. This survival activity has been shown in some settings to be influenced by the Bcl-2 phosphorylation state. It has been demon strated that treatment with microtubule-targeted agents results in phos phorylation of both Ruf-1 kinase and Bcl-2. The Bcl-2-related family member Bcl-x, also exhibits a death

The goal of this study was to determine the prevalence of sequence variants in the class I -tubul... more The goal of this study was to determine the prevalence of sequence variants in the class I -tubulin (clone m40) gene and their occurrence in human tumors and cancer cell lines. DNA was isolated from 93 control individuals representing a wide variety of ethnicities, 49 paclitaxel-naive specimens (16 ovarian cancers, 17 non-small cell lung cancers, and 16 ovarian cancer cell

Reports of multiple distinct mitoxantrone-resistant sublines without overex- pression of P-glycop... more Reports of multiple distinct mitoxantrone-resistant sublines without overex- pression of P-glycoprotein or the multidrug-resistance associated protein have raised the possibility of the existence of another major transporter conferring drug resistance. In the present study, a cDNA library from mitoxantrone-resist- ant S1-M1-80 human colon carcinoma cells was screened by differential hybrid- ization. Two cDNAs of different lengths were isolated and designated

Pharmaceutical Biology, 2003

Nature Reviews Cancer, 2002

Chemotherapeutics are the most effective treatment for metastatic tumours. However, the ability o... more Chemotherapeutics are the most effective treatment for metastatic tumours. However, the ability of cancer cells to become simultaneously resistant to different drugs--a trait known as multidrug resistance--remains a significant impediment to successful chemotherapy. Three decades of multidrug-resistance research have identified a myriad of ways in which cancer cells can elude chemotherapy, and it has become apparent that resistance exists against every effective drug, even our newest agents. Therefore, the ability to predict and circumvent drug resistance is likely to improve chemotherapy.

JNCI Journal of the National Cancer Institute, 2008

The Common Terminology Criteria for Adverse Events (CTCAE), version 3.0, and its predecessors, th... more The Common Terminology Criteria for Adverse Events (CTCAE), version 3.0, and its predecessors, the Common Toxicity Criteria (CTC) versions 1.0 and 2.0, were developed under the direction of the Cancer Therapy Evaluation Program of the National Cancer Institute (NCI) in an effort to provide standard language for reporting adverse events that occur in NCI-sponsored clinical trials. Each successive version of the CTC has improved the accuracy, precision, and completeness of the criteria in an effort to standardize reporting. We believe that the current version of the CTCAE cannot adequately code the subacute adverse events that commonly occur with today's targeted therapies.

The Cancer Journal, 2013

Adrenocortical carcinoma (ACC) is a rare and highly malignant tumor usually diagnosed in an advan... more Adrenocortical carcinoma (ACC) is a rare and highly malignant tumor usually diagnosed in an advanced stage. Radiation therapy has been a poorly studied and underutilized therapeutic option. This retrospective analysis reviewed treatment courses for 14 patients with pathologically confirmed ACC treated between 1997 and 2012. Two patients were treated adjuvantly following surgery, and 12 were treated with palliative intent. Patients presented with stage II (n = 4), stage III (n = 7), and stage IV (n = 3) disease. Patients had a mean age of 51.5 years. Ten patients received chemotherapy before radiotherapy (RT), and 12 patients received surgery before RT, before receiving radiation at a mean of 17.8 months after diagnosis. In total, 20 sites were treated, 2 of which were in an adjuvant setting, and 18 of which were for palliative indications in 12 patients as follows: (1) pain/neuropathy (n = 10), (2) prophylactic treatment of asymptomatic recurrences (n = 3), and (3) prevention of imminent metastatic complications (n = 2), hemoptysis (n = 1), severe mass effect (n = 1), and brain metastasis (n = 1). Sites were treated to a median dose of 36.3 Gy (range, 17.5-60 Gy) in a median of 2.5 Gy/fraction (range, 1.8-4 Gy). At a mean follow-up of 22.0 months for the 2 patients given adjuvant RT, 1 patient did not have a local recurrence during a 14.3-month period of follow-up, and the other had a local recurrence 14.5 months after RT. At a mean follow-up of 11.3 months for the 12 patients receiving palliative RT, 10 patients had either a clinical or radiographic response. Of the courses of palliative RT that had adequate radiographic follow-up, 4 treatments (27%) resulted in a partial response. Eleven treatments (73%) that were able to be evaluated resulted in clinical improvement. Acute Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer toxicities observed in 7 patients included 3 grade 1, 4 grade 2, and 1 grade 3. No patient had acute toxicity of grade 4 or greater or any Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer late toxicity of grade 1 or greater. This report is one of the largest to date examining the role of modern radiation techniques in the management of ACC. We conclude that radiation can be effective in the management of metastatic ACC, palliating local symptoms, and preventing complications from large metastases. Radiation should be considered as an option in multimodality management of ACC patients.

Journal of clinical oncology : official journal of the American Society of Clinical Oncology, 2003

The epothilones are a novel class of nontaxane microtubule-stabilizing agents. BMS-247550 is a se... more The epothilones are a novel class of nontaxane microtubule-stabilizing agents. BMS-247550 is a semisynthetic analog of the natural product epothilone B. We conducted a phase I study administering BMS-247550 as a 1-hour intravenous infusion daily for 5 consecutive days every 21 days. Twenty-one patients received BMS-247550 without filgrastim in the first cycle. An additional six patients were enrolled at a starting dose of 8 mg/m2/d with filgrastim support. Twenty-one of the 27 patients had received prior paclitaxel, docetaxel, or both. One hundred seven cycles were administered to 27 patients. The maximum-tolerated dose was 6 mg/m2 of BMS-247550 administered as a 1-hour intravenous infusion daily for 5 consecutive days every 21 days. Dose-limiting toxicity at a dose of 8 mg/m2/d was neutropenia with or without filgrastim support. Nonhematologic grade 3 toxicities included fatigue (seven cycles), stomatitis (two cycles), and anorexia (one cycle). The mean terminal half-life of BMS-24...

The Journal of Clinical Endocrinology & Metabolism, 2014

Adrenocortical carcinoma (ACC) is a rare malignancy with a poor prognosis in need of more effecti... more Adrenocortical carcinoma (ACC) is a rare malignancy with a poor prognosis in need of more effective treatment options. Published evidence indicates many ACCs express the vascular endothelial growth factor receptor (VEGFR), suggesting inhibiting vascular endothelial growth factor signaling could potentially impact tumor growth. The objective of the study was to determine the antitumor efficacy of axitinib (AG-013736), a potent, selective inhibitor of VEGFR1, -2, and -3. This was a phase II, open-label trial using a two-stage design. Thirteen patients with metastatic ACC previously treated with at least one chemotherapy regimen with or without mitotane participated in the study. Starting axitinib dose was 5 mg orally twice daily. Dose escalations were permitted if the administered dose was tolerable. Thirteen patients were enrolled. Dose escalation was possible in seven patients, but the majority could not tolerate a dose higher than the starting 5 mg, twice-daily dose for prolonged periods of time. All patients experienced known grade 1/2 toxicities, and 10 of 13 patients had at least one grade 3/4 adverse event. No patient tumor could be scored as a Response Evaluation Criteria in Solid Tumors response, although the growth rate on therapy compared with that prior to starting axitinib was reduced in 4 of the 13 patients. The median progression-free survival was 5.48 months, and the median overall survival was longer than 13.7 months. Axitinib has limited effectiveness in ACC. Together with 48 patients previously reported who received either sorafenib or sunitinib, a total of 61 ACC patients have now been treated with a VEGFR tyrosine kinase inhibitor without an objective Response Evaluation Criteria in Solid Tumors response. Future trials in ACC should look to other targets for possible active agents.

The oncologist, Jan 3, 2015

Accrual to cervical cancer studies remains a puzzling challenge given the lack of options and the... more Accrual to cervical cancer studies remains a puzzling challenge given the lack of options and the dismal prognosis of this disease. The majority of patients referred for a trial such as this have very advanced disease that is difficult to manage.The observation of 4 partial responses among the 41 patients indicates that ixabepilone has some activity but not sufficient for further development without greater understanding of mechanisms of sensitivity and resistance. Ixabepilone is a microtubule-stabilizing agent approved for metastatic breast cancer. Preclinical data have shown that ixabepilone is active in taxane-sensitive and -resistant cells. Metastatic cervical carcinoma (mCC) has a poor prognosis and no established second-line therapies. This study assessed the efficacy and safety of ixabepilone in previously treated mCC. Patients with histologically confirmed mCC and at least one prior cisplatin-containing regimen were treated with ixabepilone [6 mg/m(2) per day for 5 days] eve...

The American Journal of Cardiology, 2015

Pheochromocytomas and paragangliomas are chromaffin cell tumors arising from neuroendocrine cells... more Pheochromocytomas and paragangliomas are chromaffin cell tumors arising from neuroendocrine cells. At least 1/3 of paragangliomas are related to germline mutations in 1 of 17 genes. Although these tumors can occur throughout the body, cardiac paragangliomas are very rare, accounting for <0.3% of mediastinal tumors. The purpose of this study was to determine the clinical characteristics of patients with cardiac paragangliomas, particularly focusing on their genetic backgrounds. A retrospective chart analysis of 15 patients with cardiac paragangliomas was performed to determine clinical presentation, genetic background, diagnostic workup, and outcomes. The average age at diagnosis was 41.9 years. Typical symptoms of paraganglioma (e.g., hypertension, sweating, palpitations, headache) were reported at initial presentation in 13 patients (86.7%); the remaining 2, as well as 4 symptomatic patients, initially presented with cardiac-specific symptoms (e.g., chest pain, dyspnea). Genetic testing was done in 13 patients (86.7%); 10 (76.9%) were positive for mutations in succinate dehydrogenase (SDHx) subunits B, C, or D. Thirteen patients (86.7%) underwent surgery to remove the paraganglioma with no intraoperative morbidity or mortality; 1 additional patient underwent surgical resection but experienced intraoperative complications after removal of the tumor due to co-morbidities and did not survive. SDHx mutations are known to be associated with mediastinal locations and malignant behavior of paragangliomas. In this report, the investigators extend the locations of predominantly SDHx-related paragangliomas to cardiac tumors. In conclusion, cardiac paragangliomas are frequently associated with underlying SDHx germline mutations, suggesting a need for genetic testing of all patients with this rare tumor.

The Journal of biological chemistry, Jan 4, 1997

Acquired resistance to paclitaxel can be mediated by P-glycoprotein or by alterations involving t... more Acquired resistance to paclitaxel can be mediated by P-glycoprotein or by alterations involving tubulin. We report two paclitaxel-resistant sublines derived from 1A9 human ovarian carcinoma cells. Single-step paclitaxel selection with verapamil yielded two clones that are resistant to paclitaxel and collaterally sensitive to vinblastine. The resistant sublines are not paclitaxel-dependent, and resistance remained stable after 3 years of drug-free culture. All cell lines accumulate [3H]paclitaxel equally, and no MDR-1 mRNA was detected by polymerase chain reaction following reverse transcription. Total tubulin content is similar, but the polymerized fraction increased in parental but not in resistant cells following the paclitaxel addition. Purified tubulin from parental cells demonstrated paclitaxel-driven increased polymerization, in contrast to resistant cell tubulin, which did not polymerize under identical conditions. In contrast, epothilone B, an agent to which the resistant ce...

Cancer research, 2014

Successful cancer treatments are generally defined as those that decrease tumor quantity. In many... more Successful cancer treatments are generally defined as those that decrease tumor quantity. In many cases, this decrease occurs exponentially, with deviations from a strict exponential being attributed to a growing fraction of drug-resistant cells. Deviations from an exponential decrease in tumor quantity can also be expected if drugs have a nonuniform spatial distribution inside the tumor, for example, because of interstitial pressure inside the tumor. Here, we examine theoretically different models of cell killing and analyze data from clinical trials based on these models. We show that the best description of clinical outcomes is by first-order kinetics with exponential decrease of tumor quantity. We analyzed the total tumor quantity in a diverse group of clinical trials with various cancers during the administration of different classes of anticancer agents and in all cases observed that the models that best fit the data describe the decrease of the sensitive tumor fraction expone...

Cancer research, Jan 15, 2003

Hemiasterlin is a natural product derived from marine sponges that, like other structurally diver... more Hemiasterlin is a natural product derived from marine sponges that, like other structurally diverse peptide-like molecules, binds to the Vinca-peptide site in tubulin, disrupts normal microtubule dynamics, and, at stoichiometric amounts, depolymerizes microtubules. Total synthesis of hemiasterlin and its analogues has been accomplished, and optimal pharmacological features of the series have been explored. The biological profile of one analogue, HTI-286, was studied here. HTI-286 inhibited the polymerization of purified tubulin, disrupted microtubule organization in cells, and induced mitotic arrest, as well as apoptosis. HTI-286 was a potent inhibitor of proliferation (mean IC(50) = 2.5 +/- 2.1 nM in 18 human tumor cell lines) and had substantially less interaction with multidrug resistance protein (P-glycoprotein) than currently used antimicrotubule agents, including paclitaxel, docetaxel, vinorelbine, or vinblastine. Resistance to HTI-286 was not detected in cells overexpressing ...

Molecular Therapy, 2005

Adenovirus gene therapy is frequently inefficient because of low levels of coxsackie adenovirus r... more Adenovirus gene therapy is frequently inefficient because of low levels of coxsackie adenovirus receptor (CAR) the primary adenovirus receptor. Previously, we showed that treatment of a diverse group of cancer cell lines with the histone deacetylase inhibitor FK228 (FR901228, depsipeptide), a drug in phase II clinical trials for the treatment of peripheral and cutaneous T-cell lymphoma, caused increases in CAR

JAMA Otolaryngology–Head & Neck Surgery, 2014

Cancer is expected to continue as a major health and economic problem worldwide. Several factors ... more Cancer is expected to continue as a major health and economic problem worldwide. Several factors are contributing to the increasing economic burden imposed by cancer, with the cost of cancer drugs an undeniably important variable. The use of expensive therapies with marginal benefits for their approved indications and for unproven indications is contributing to the rising cost of cancer care. We believe that expensive therapies are stifling progress by (1) encouraging enormous expenditures of time, money, and resources on marginal therapeutic indications and (2) promoting a me-too mentality that is stifling innovation and creativity. The modest gains of Food and Drug Administration-approved therapies and the limited progress against major cancers is evidence of a lowering of the efficacy bar that, together with high drug prices, has inadvertently incentivized the pursuit of marginal outcomes and a me-too mentality evidenced by the duplication of effort and redundant pharmaceutical pipelines. We discuss the economic realities that are driving this process and provide suggestions for radical changes to reengineer our collective cancer ecosystem to achieve better outcomes for society.

Molecular Cancer Therapeutics, 2007

Nature Reviews Cancer, 2005

The contribution of tumorigenic stem cells to haematopoietic cancers has been established for som... more The contribution of tumorigenic stem cells to haematopoietic cancers has been established for some time, and cells possessing stem-cell properties have been described in several solid tumours. Although chemotherapy kills most cells in a tumour, it is believed to leave tumour stem cells behind, which might be an important mechanism of resistance. For example, the ATP-binding cassette (ABC) drug transporters

The oncogenic protein Bcl-2 functions as a potent inhibitor of pro grammed cell death. This survi... more The oncogenic protein Bcl-2 functions as a potent inhibitor of pro grammed cell death. This survival activity has been shown in some settings to be influenced by the Bcl-2 phosphorylation state. It has been demon strated that treatment with microtubule-targeted agents results in phos phorylation of both Ruf-1 kinase and Bcl-2. The Bcl-2-related family member Bcl-x, also exhibits a death

The goal of this study was to determine the prevalence of sequence variants in the class I -tubul... more The goal of this study was to determine the prevalence of sequence variants in the class I -tubulin (clone m40) gene and their occurrence in human tumors and cancer cell lines. DNA was isolated from 93 control individuals representing a wide variety of ethnicities, 49 paclitaxel-naive specimens (16 ovarian cancers, 17 non-small cell lung cancers, and 16 ovarian cancer cell

Reports of multiple distinct mitoxantrone-resistant sublines without overex- pression of P-glycop... more Reports of multiple distinct mitoxantrone-resistant sublines without overex- pression of P-glycoprotein or the multidrug-resistance associated protein have raised the possibility of the existence of another major transporter conferring drug resistance. In the present study, a cDNA library from mitoxantrone-resist- ant S1-M1-80 human colon carcinoma cells was screened by differential hybrid- ization. Two cDNAs of different lengths were isolated and designated

Pharmaceutical Biology, 2003

Nature Reviews Cancer, 2002

Chemotherapeutics are the most effective treatment for metastatic tumours. However, the ability o... more Chemotherapeutics are the most effective treatment for metastatic tumours. However, the ability of cancer cells to become simultaneously resistant to different drugs--a trait known as multidrug resistance--remains a significant impediment to successful chemotherapy. Three decades of multidrug-resistance research have identified a myriad of ways in which cancer cells can elude chemotherapy, and it has become apparent that resistance exists against every effective drug, even our newest agents. Therefore, the ability to predict and circumvent drug resistance is likely to improve chemotherapy.