Metal-ion speciation in blood plasma incorporating the tetraphosphonate, N,N-dimethylenephosphonate-1-hydroxy-4-aminopropilydenediphosphonate (APDDMP), in therapeutic radiopharmaceuticals

In a quest for more effective radiopharmaceuticals for pain palliation of metastatic bone cancer, this paper relates results obtained with 166Ho and 153Sm complexed to the bone seeking phosphonate, N,N-dimethylenephosphonate-1-hydroxy-4-aminopropylidenediphosphonate (APDDMP). APDDMP is synthesised from the known bone cancer pain palliation agent 1-hydroxy-3-aminopropylidenediphosphonate (APD) and was complexed to lanthanide trivalent metal ions. This work is performed to utilise the idea that the energetic beta-particle emitter, 166 Ho, coupled with phosphonate ligands such as APD and APDDMP could afford a highly effective radiopharmaceutical in the treatment of bone cancer. Complex-formation constants of APDDMP with the important blood plasma metal-ions, Ca2+, Mg2+, and Zn2+ and the trivalent lanthanides Ho3+ and Sm3+ were measured by glass electrode potentiometry at 37 degrees C and I = 150 mM. Blood plasma models were constructed using the computer code ECCLES and the results compared with those gathered from animal tests. The 166Ho-APDDMP complex was found to have little liver or bone uptake while 153Sm-APDDMP had a moderate bone uptake. This was primarily due to the high affinity of APDDMP for Ca(II). Clinical observations could be explained by the blood plasma modelling.     

Comparison of the predicted in vivo behaviour of the Sn(II)-APDDMP complex and the results as studied in a rodent model

In a quest for more effective radiopharmaceuticals for pain palliation of metastatic bone cancer, this paper relates results obtained with ((117m)Sn labelled) Sn(II) complexed to the bone seeking bisphosphonate, N,N-dimethylenephosphonate-1-hydroxy-3-aminopropylidenediphosphonate (APDDMP). APDDMP is synthesised from the known bone cancer pain palliation agent 1-hydroxy-3-aminopropylidenediphosphonate (APD, Pamindronate). This work is performed to utilise the idea that the low bone marrow radio toxicity of (117m)Sn could afford a highly effective radiopharmaceutical in pain palliation but also in the curative treatment of bone metastasis. Complex-formation constants of APDDMP with the important blood plasma metal-ions, Ca(2+), Mg(2+), Zn(2+) as well as the added metal ion, Sn(2+) were measured by glass electrode potentiometry at 25 degrees C and I = 150 mM. Blood plasma models were constructed using the computer code ECCLES and the results compared with those gathered from tests on a rodent model. The ((117m)Sn-labelled) Sn(II)-APDDMP complex was found to have only some liver and bone uptake although a high trabecular to normal bone ratio was recorded. From the blood plasma model this was shown to be primarily due to the high affinity of APDDMP for Ca(II) causing some of the Sn(II)-APDDMP complex to dissociate. High kidney uptake and excretion as well as high bladder uptake was recorded which was shown to be due to the dissociation of the Sn(II)-APDDMP complex in blood plasma. Animal model observations could be explained by the blood plasma modelling.     

13- and 14-membered macrocyclic ligands containing methylcarboxylate or methylphosphonate pendant arms: chemical and biological evaluation of their (153)Sm and (166)Ho complexes as potential agents for therapy or bone pain palliation

The stability constants of La(3+), Sm(3+) and Ho(3+) complexes with 13- and 14-membered macrocycles having methylcarboxylate (trita and teta) or methylphosphonate (tritp and tetp) arms were determined. All the ligands were labelled with (153)Sm and (166)Ho in order to evaluate the effect of the macrocyclic cavity size and type of appended arms on their in vitro and in vivo behaviour. The radiolabelling efficiency was found to be higher than 98% for all the complexes, except for those of tetp. All radiocomplexes studied are hydrophilic with an overall negative charge and low plasmatic protein binding. Good in vitro stability in physiological media and human serum was found for all complexes, except the (153)Sm/(166)Ho-teta, which are unstable in phosphate buffer (pH 7.4). In vitro hydroxyapatite (HA) adsorption studies indicated that (153)Sm/(166)Ho-tritp complexes bind to HA having the (166)Ho complex the highest degree of adsorption (>80%, 10 mg). Biodistribution studies in mice demonstrated that (153)Sm/(166)Ho-trita complexes have a fast tissue clearance with more than 95% of the injected activity excreted after 2 h, value that is comparable to the corresponding dota complexes. In contrast, the (153)Sm-teta complex has a significantly lower total excretion. (153)Sm/(166)Ho-tritp complexes are retained by the bone, particularly (166)Ho-tritp that has 5-6% (% I.D./g) bone uptake and also a high rate of total excretion. Thus, these studies support the potential interest of (153)Sm/(166)Ho-trita complexes for therapy when conjugated to a biomolecule and the potential usefulness of the (166)Ho-tritp complex in bone pain palliation.     

THE TREATMENT OF METASTATIC BREAST CANCER IN BONE

The author report clinical experience with 212 cases of mammary cancer metastatic to bone, in 186 of which radiotherapy was given, and in 26 steroid hormone therapy.At least 70 per cent of patients with bone metastasis from breast cancer were relieved of pain by adequate roentgen therapy, the relief lasting for most of the survival time in many instances.About 25 per cent of patients had recalcification or reossification of bony lesions with roentgen therapy; while dramatic, this is not always an indication that relief of pain will continue or that survival time will be lengthened.If and when adequate radiotherapy has not been effective or cannot be administered (for example, in a patient with extremely widespread metastasis, or one residing at a considerable distance from radiotherapeutic service) steroid hormone therapy in adequate dosage is frequently beneficial. From 40 per cent to 75 per cent of patients with bone metastases from breast cancer are relieved of pain by steroid hormone therapy. In about 15 per cent of cases recalcification of the lesion occurs.Effective roentgen therapy may usually be given in a relatively brief period of time (one to two weeks). Effective steroid hormone therapy usually requires from 12 to 24 weeks.Complications of steroid hormone therapy are numerous. Some patients are made considerably worse by such therapy. These complications may only be controlled by reduction or discontinuation of the hormones. For this reason, it is recommended that irradiation always be used as the initial method of palliation.     

Voltammetry as a virtual potentiometric sensor in modelling of a metal-ligand system and refinement of stability constants. Part 4. An electrochemical study of NiII complexes with methylene diphosphonic acid

The Ni(II)-MDP-OH system (MDP=methylene diphosphonic acid) and stability constants of complexes formed at ionic strength 0.15M at 298K were established by direct current polarography (DCP) and glass electrode potentiometry (GEP). The final M-L-OH model could only be arrived to by employing recent concept of virtual potentiometry (VP). VP-data were generated from non-equilibrium and dynamic DC polarographic technique. The VP and GEP data were refined simultaneously by software dedicated to potentiometric studies of metal complexes. Species distribution diagrams that were generated for different experimental conditions employed in this work assisted in making the final choice regarding the metal-ligand model. The model established contains ML, ML(2), ML(OH) and ML(OH)(2) with stability constants, as logbeta, 7.94+/-0.02, 13.75+/-0.02, 12.04 (fixed value), and 16.75+/-0.05, respectively. It has been demonstrated that virtual potential must be used in modelling operations (predictions of species formed) when a polarographic signal decreases significantly due to the formation of polarographically inactive species (or formation of inert complexes). The linear free energy relationships that included stability constant logK(1) for Ni(II)-MDP established in this work together with other available data were used to predict logK(1) values for Sm(III) and Ho(III) with MDP. The logK(1) values for Sm(III)-MDP and Ho(III)-MDP were estimated to be 9.65+/-0.10 and 9.85+/-0.10, respectively.     

Radiolanthanide-labeled monoclonal antibody CC49 for radioimmunotherapy of cancer: biological comparison of DOTA conjugates and 149Pm, 166Ho, and 177Lu

The radiolanthanides 149Pm, 166Ho, and 177Lu have decay characteristics suitable for radioimmunotherapy (RIT) of cancer. N-Hydroxysulfosuccinimidyl DOTA (DOTA-OSSu) and methoxy-DOTA (MeO-DOTA) were conjugated to the anti-TAG-72 monoclonal antibody CC49 for radiolabeling with 149Pm, 166Ho, and 177Lu. While both DOTA conjugates could be labeled to high specific activity with 177Lu, MeO-DOTA afforded superior conjugate stability, radiolabeling, and radiochemical purity. Pilot biodistributions in nude mice bearing LS174T human colon carcinoma xenografts demonstrated that MeO-DOTA afforded higher tumor uptake and lower kidney retention of 177Lu than DOTA-OSSu. The in vitro stability of 149Pm-, 166Ho-, and 177Lu-MeO-DOTA-CC49 was evaluated using serum and hydroxyapatite assays. Serum stability of radiolanthanide-labeled MeO-DOTA-CC49 followed a trend based on the coordination energies of the radiometals, with 177Lu showing the highest stability after 96 to 168 h at 37 C. In contrast, MeO-DOTA-CC49 labeled with all three radiolanthanides was >92% stable to hydroxyapatite challenge for 168 h at 37 C. Comprehensive biodistributions of 149Pm-, 166Ho-, and 177Lu-MeO-DOTA-CC49 were obtained in LS174T-bearing nude mice. Maximum tumor uptakes were 100.0% ID/g for 149Pm at 96 h, 69.5% ID/g for 166Ho at 96 h, and 132.4% ID/g for 177Lu at 168 h. Normal organ uptakes were generally low, except in the liver, spleen, and kidney at early time points. By 96 to 168 h postinjection, nontarget organ uptake decreased to approximately 7% ID/g (kidney), 12% ID/g (spleen), and 20% ID/g (liver) for each radiolanthanide. When labeled with 149Pm, 166Ho, and 177Lu, MeO-DOTA-CC49 has potential for RIT of colorectal cancer and other carcinomas.     

166Holmium-containing glass for internal radiotherapy of tumors

Aluminosilicate glass containing the β-emitter ¹⁶⁶Ho was tested for tumor cell killing effectiveness with the BT-20 human mammary carcinoma cell line as a model. Incubation of BT-20 cells with ¹⁶⁶Ho glass partially inhibited DNA replication and completely blocked growth in cells located within 1.0 mm of the radioactive fiber. Growth of BT-20 tumor xenografts in nude mice was dramatically inhibited by injection of 2–5 μm fragments of ¹⁶⁶Ho glass (200 μ Ci/tumor). The results suggest that ¹⁶⁶Ho glass would be an effective modality for deposition of intense β⁻ radiation for localized internal radiotherapy of tumors.     

Osteolytic lesion in chronic myelogenous leukaemia

Destructive bone lesion of the femur was observed in one patient from a series of 103 patients with CML. Numerous myeloblasts were seen on touch preparations of the fresh surgical specimen obtained by open biopsy of the affected area. Bone marrow and peripheral blood differential count were compatible with chronic phase of CML at this time. 5 months later blastic crisis developed. Local radiotherapy produced effective palliation of pain but did not prevent blastic transformation of CML. The treatment of blastic crisis was unsuccessful and patient died 3 years after diagnosis of CML, 6 months after the first clinical evidence of bone infiltration.     

Quantitative evaluation of scintillation camera imaging characteristics of isotopes used in liver radioembolization

Background

Scintillation camera imaging is used for treatment planning and post-treatment dosimetry in liver radioembolization (RE). In yttrium-90 (90Y) RE, scintigraphic images of technetium-99m (99mTc) are used for treatment planning, while 90Y Bremsstrahlung images are used for post-treatment dosimetry. In holmium-166 (166Ho) RE, scintigraphic images of 166Ho can be used for both treatment planning and post-treatment dosimetry. The aim of this study is to quantitatively evaluate and compare the imaging characteristics of these three isotopes, in order that imaging protocols can be optimized and RE studies with varying isotopes can be compared.

Methodology/Principal Findings

Phantom experiments were performed in line with NEMA guidelines to assess the spatial resolution, sensitivity, count rate linearity, and contrast recovery of 99mTc, 90Y and 166Ho. In addition, Monte Carlo simulations were performed to obtain detailed information about the history of detected photons. The results showed that the use of a broad energy window and the high-energy collimator gave optimal combination of sensitivity, spatial resolution, and primary photon fraction for 90Y Bremsstrahlung imaging, although differences with the medium-energy collimator were small. For 166Ho, the high-energy collimator also slightly outperformed the medium-energy collimator. In comparison with 99mTc, the image quality of both 90Y and 166Ho is degraded by a lower spatial resolution, a lower sensitivity, and larger scatter and collimator penetration fractions.

Conclusions/Significance

The quantitative evaluation of the scintillation camera characteristics presented in this study helps to optimize acquisition parameters and supports future analysis of clinical comparisons between RE studies.     

The effect of two different doses of oral clodronate on pain in patients with bone metastases

The aim of this study was to evaluate the efficacy of low dose oral clodronate in palliation of pain arising from bone metastases (BM) and to determine the optimal oral clodronate dose which inhibits osteolysis caused by tumor. Fifty patients with bone pain caused by BM were included in this study. All were receiving antitumor chemotherapy or hormonal therapy. The patients were randomized into three groups according to the dose of clodronate. Groups A and B were given 800 mg/d and 1600 mg/d of oral clodronate respectively for 3 months. Group C was the control group. The effect of clodronate in pain palliation was evaluated with pain score, performance status, and changes in analgesic use. The effect on osteolysis was examined with urinary calcium, hydroxyproline (OHP) and serum cross-linked carboxyterminal telopeptide region of type I collagen (ICTP) levels. Group A contained 16 patients, and groups B and C contained 17 patients each. After 3 months use of oral clodronate, significant decrease in the pain score of groups A and B was noted when, compared to group C (P=0.024 andP=0.007, respectively) The analgesic use of 11 patients in group A (69%) and 8 patients in group B (47%) was decreased, but only the decrease in group A was statistically significant (P=0.038). Pain score increased in 5 patients in group C (29%), and 3 patients in groups A (19%) and B (18%) each. Urinary calcium, OHP and serum ICTP levels increased in group C and decreased in groups A and B, but only the decrease of urinary calcium levels of group B was significant (P=0.003). In conclusion, low dose (800 mg/d) oral clodronate seems to be as effective as standard dose (1600 mg/d) in palliation of bone pain secondary to BM.     

The role of alpha 6 integrin in prostate cancer migration and bone pain in a novel xenograft model

Of the estimated 565,650 people in the U.S. who will die of cancer in 2008, almost all will have metastasis. Breast, prostate, kidney, thyroid and lung cancers metastasize to the bone. Tumor cells reside within the bone using integrin type cell adhesion receptors and elicit incapacitating bone pain and fractures. In particular, metastatic human prostate tumors express and cleave the integrin A6, a receptor for extracellular matrix components of the bone, i.e., laminin 332 and laminin 511. More than 50% of all prostate cancer patients develop severe bone pain during their remaining lifetime. One major goal is to prevent or delay cancer induced bone pain. We used a novel xenograft mouse model to directly determine if bone pain could be prevented by blocking the known cleavage of the A6 integrin adhesion receptor. Human tumor cells expressing either the wildtype or mutated A6 integrin were placed within the living bone matrix and 21 days later, integrin expression was confirmed by RT-PCR, radiographs were collected and behavioral measurements of spontaneous and evoked pain performed. All animals independent of integrin status had indistinguishable tumor burden and developed bone loss 21 days after surgery. A comparison of animals containing the wild type or mutated integrin revealed that tumor cells expressing the mutated integrin resulted in a dramatic decrease in bone loss, unicortical or bicortical fractures and a decrease in the ability of tumor cells to reach the epiphyseal plate of the bone. Further, tumor cells within the bone expressing the integrin mutation prevented cancer induced spontaneous flinching, tactile allodynia, and movement evoked pain. Preventing A6 integrin cleavage on the prostate tumor cell surface decreased the migration of tumor cells within the bone and the onset and degree of bone pain and fractures. These results suggest that strategies for blocking the cleavage of the adhesion receptors on the tumor cell surface can significantly prevent cancer induced bone pain and slow disease progression within the bone. Since integrin cleavage is mediated by Urokinase-type Plasminogen Activator (uPA), further work is warranted to test the efficacy of uPA inhibitors for prevention or delay of cancer induced bone pain.     

The application of cryosurgery in the treatment of lung cancer

Lung cancer is the commonest cause of cancer death, with a very poor survival rate. By the time of diagnosis, most cases are at an advanced stage and about 30% present with symptoms caused by central endobronchial obstruction. Endobronchial cryosurgery is an effective technique, which can be used to relieve tracheobronchial obstruction caused by lung cancer. This report describes the technique, using a nitrous oxide cooled cryoprobe, inserted through a bronchoscope, to remove the obstruction and reopen the airway. In this study, 476 consecutive patients (mean age 68.3 years, M:F ratio 1.9:1) with obstructive tracheobronchial tumours underwent a mean of 2.4 cryosurgical treatments. Their TNM staging was, stage II 6.7%, IIIa 21.0%, IIIb 23.9%, IV 48.4%. Improvement in symptom quantification was found with 76.4, 69.0, 59.2, and 42.6% of symptomatic patients for haemoptysis, cough, dyspnoea, and chest pain, respectively. Mean values for respiratory function improved from 1.38 to 1.41 litres for FEV1 and 1.91 to 2.04 litres for FVC (p 相似文献   

Tumor Tissue-Derived Formaldehyde and Acidic Microenvironment Synergistically Induce Bone Cancer Pain

Background

There is current interest in understanding the molecular mechanisms of tumor-induced bone pain. Accumulated evidence shows that endogenous formaldehyde concentrations are elevated in the blood or urine of patients with breast, prostate or bladder cancer. These cancers are frequently associated with cancer pain especially after bone metastasis. It is well known that transient receptor potential vanilloid receptor 1 (TRPV1) participates in cancer pain. The present study aims to demonstrate that the tumor tissue-derived endogenous formaldehyde induces bone cancer pain via TRPV1 activation under tumor acidic environment.

Methodology/Principal Findings

Endogenous formaldehyde concentration increased significantly in the cultured breast cancer cell lines in vitro, in the bone marrow of breast MRMT-1 bone cancer pain model in rats and in tissues from breast cancer and lung cancer patients in vivo. Low concentrations (1∼5 mM) of formaldehyde induced pain responses in rat via TRPV1 and this pain response could be significantly enhanced by pH 6.0 (mimicking the acidic tumor microenvironment). Formaldehyde at low concentrations (1 mM to 100 mM) induced a concentration-dependent increase of [Ca²⁺]i in the freshly isolated rat dorsal root ganglion neurons and TRPV1-transfected CHO cells. Furthermore, electrophysiological experiments showed that low concentration formaldehyde-elicited TRPV1 currents could be significantly potentiated by low pH (6.0). TRPV1 antagonists and formaldehyde scavengers attenuated bone cancer pain responses.

Conclusions/Significance

Our data suggest that cancer tissues directly secrete endogenous formaldehyde, and this formaldehyde at low concentration induces metastatic bone cancer pain through TRPV1 activation especially under tumor acidic environment.     

Studies on the analgesic activities of Jia-Yuan-Qing pill and its safety evaluation in mice

The analgesic activity of Porcellio laevis Latreille, Rhizoma Corydalis, and Radix Cynanchi Paniculati have been reported in recent years. A new formula named Jia-Yuan-Qing pill (JYQP) is therefore created by combining the three herbs at 9:7:7 ratio according to traditional Chinese theories. The present study aims to evaluate the effect of JYQP as a novel painkiller in various models. Acute toxicity test was applied to evaluate the safety of JYQP. Acetic-acid-induced writhing, hot plate test, formalin test, and naloxone-pretreated writhing test were employed to elaborate the analgesic activity of JYQP and its possible mechanism. A bone cancer pain mouse model was performed to further assess the effect of JYQP in relieving cancer pain. Test on naloxone-precipitated withdrawal symptoms was conduct to examine the physical dependence of mice on JYQP. Data revealed that JYQP reduced writhing and stretching induced by acetic acid; however, this effect could not be blocked by naloxone. JYQP specifically suppressed the phase II reaction time in formalin-treated mice; meanwhile, no analgesic effect of JYQP in hot plate test was observed, indicating that JYQP exerts analgesic activity against inflammatory pain rather than neurogenic pain. Furthermore, JYQP could successfully relieve bone cancer pain in mice. No physical dependence could be observed upon long-term administration in mice. Collectively, our present results provide experimental evidence in supporting clinical use of JYQP as an effective and safe agent for pain treatment.     

Osteoprotegerin blocks bone cancer-induced skeletal destruction, skeletal pain and pain-related neurochemical reorganization of the spinal cord

Bone cancer pain is common among cancer patients and can have a devastating effect on their quality of life. A chief problem in designing new therapies for bone cancer pain is that it is unclear what mechanisms drive this distinct pain condition. Here we show that osteoprotegerin, a secreted 'decoy' receptor that inhibits osteoclast activity, also blocks behaviors indicative of pain in mice with bone cancer. A substantial part of the actions of osteoprotegerin seems to result from inhibition of tumor-induced bone destruction that in turn inhibits the neurochemical changes in the spinal cord that are thought to be involved in the generation and maintenance of cancer pain. These results demonstrate that excessive tumor-induced bone destruction is involved in the generation of bone cancer pain and that osteoprotegerin may provide an effective treatment for this common human condition.     

Persistent pain accelerates xenograft tumor growth of breast cancer in rat

Pain occurs at all stages of the patients who suffer from cancer. Owing to surgery and bone metastasis, breast cancer patients were usually disturbed by persistent pain. However, the pain-relief-right has not been respected enough in clinical cancer treatment. Whether pain has any adverse effects on cancer development is still unclear. In order to uncover this question, we established two preclinical animal models to explore the effects of pain on the tumor. For the first model, we mimicked neuropathic pain by sciatic nerve ligation on rats with xenograft tumor subcutaneously. For the second model, we mimicked the bone cancer pain by injecting tumor cell suspension into the tibial medullary cavity of rats with xenograft tumor subcutaneously. The rats with persistent pain showed higher tumor volume and tumor weight compared with the group without pain. Interestingly, when the neuropathic pain and bone cancer pain were relieved by drug administration, both the tumor volume and tumor weight were lowered compared with the group without pain relief. In summary, our study indicated that persistent pain acted as a contributing factor to tumor growth. Moreover, the pain relief could weakened the accelerating role of pain in tumor growth. Thus, we should be paid more attention to the cancer patients with persistent pain as well as cancer treatment.     

Behavioural assessment of the effects of tumour growth in rats and the influence of the analgesics carprofen and meloxicam

Very little is known concerning the occurrence of pain in cancer research models. We wished to establish whether a behaviour-based approach, originally developed to assess postoperative pain, could be used to determine positive effects of the analgesics carprofen and meloxicam in rats that might be experiencing pain during tumour development in an orthotopic model of bladder cancer. An invasive but non-metastatic rat bladder cancer cell line was surgically implanted into the bladder wall of 57 inbred Fisher344 rats. The rats underwent daily clinical assessments. When clinical signs consistent with chronic pain were apparent, behavioural data were collected from 44 animals during 2 x 10 min periods, immediately before and one hour after a subcutaneous injection of either physiological saline (0.9%; 0.2 ml/100 g), carprofen (5 mg/kg) or meloxicam (2 mg/kg). Treatment-associated behaviour changes were then compared between groups. The lack of active behaviour, both before and after each treatment, was consistent with established clinical signs of pain. The rats were so inactive following the treatment that the behavioural technique we had previously developed was of comparatively little use in determining either pain severity or analgesic efficacy. One very prominent effect, however, was an increase in ventral abdominal licking in the control (saline) group. As this was absent in rats given meloxicam or carprofen, and has previously been considered to indicate pain emanating from damaged tissue, it was concluded that the analgesic-treated rats gained at least some benefit from the drug treatments, but it was not possible to gauge the extent of this. Handling for examination or treatment may have intensified pain in rats in the control group, and so this should be avoided whenever possible. It is likely that post-surgical pain differs markedly from cancer pain, so a different set of behavioural markers may be needed to assess it effectively. More intensive behaviour monitoring may help to develop a suitable technique for detecting the onset of, and assess the severity of pain that may occur during tumour development.     

Elimination of Colon Cancer Stem-Like Cells by the Combination of Curcumin and FOLFOX

5-Fluorouracil (5-FU) or 5-FU plus oxaliplatin (FOLFOX) remains the backbone of colorectal cancer chemotherapeutics but with limited success. This could partly be due to the enrichment of cancer stem cells (CSCs) that are resistant to conventional chemotherapy. Therefore, validation of a nontoxic agent that can either cause reversal of chemoresistance or promote the killing of CSCs would be highly desirable. The current study examines whether curcumin, the major active ingredient of turmeric, either alone or together with FOLFOX, would be an effective strategy to eliminate colon CSCs. Exposure of colon cancer HCT-116 or HT-29 cells to FOLFOX that inhibited their growth led to the enrichment of CSC phenotype as evidenced by increased proportion of CD133-, CD44-, and/or CD166-positive cells and epidermal growth factor receptor (EGFR) levels. Treatment of FOLFOX-surviving colon cancer cells with either curcumin alone or together with FOLFOX resulted in a marked reduction in CSCs, as evidenced by the decreased expression of CD44 and CD166 as well as EGFR and by their ability to form anchorage-dependent colonies. They also caused disintegration of colonospheres. Increased expression of EGFR in FOLFOX-surviving cells could be attributed to hypomethylation of the EGFR promoter, whereas an opposite phenomenon was observed when the FOLFOX-surviving cells were treated with curcumin and/or FOLFOX. These changes were accompanied by parallel alterations in the levels of DNA methyltransferase 1. In conclusion, our data suggest that curcumin by itself or together with the conventional chemotherapeutic could be an effective treatment strategy for preventing the emergence of chemoresistant colon cancer cells by reducing/eliminating CSCs.