PubMed Health⌕ Search

Biomedical subjects

L C Panasci

Publications and source records attributed to L C Panasci.

At least 19 recordsLinked to original sources

Polyethyleneimine grafted with pluronic P85 enhances Ku86 antisense delivery and the ionizing radiation treatment efficacy in vivo.

In an effort to improve the efficacy of antisense delivery, we evaluated polyethyleneimine (PEI, 2 kDa) alone or grafted with nonionic amphiphilic block copolymer Pluronic (P85) as a carrier for Ku86 antisense oligonucleotide (ASO) delivery. Ku86 is an abundant nuclear protein that plays an important role in nonhomologous DNA end joining and has implications in tumorigenesis and acquired drug resistance. Transfection of adherent and suspension cell lines with Ku86 ASOs complexed with P85-g-PEI (2 kDa) conjugates was associated with a specific decrease in Ku86 mRNA levels (EC50<75 nM and EC50<250 nM, respectively, n=3). More importantly, no requirement for reduced serum conditions was necessary during transfection. In contrast, whereas Ku86 ASOs complexed with PEI (2 kDa) alone were effective in decreasing Ku86 mRNA levels in adherent cell lines (EC50<75 nM, n=3), the formulation did not produce any detectable decrease in Ku86 mRNA levels in suspension cell lines. Transfection of adherent cell lines with 500 nM Ku86 ASOs formulated with P85-g-PEI (2 kDa) was associated with a specific decrease (<10% remaining of control) in Ku86 protein expression and a two-fold increased cell death after treatment with ionizing radiation (IR). In athymic nude mice bearing subcutaneous human HT29 colon adenocarcinoma xenografts, Ku86 ASO-P85-g-PEI (2 kDa) administration (15 mg/kg, subcutaneously) with a Q1D x 7 treatment schedule, when combined with a single dose of IR (6 Gy), caused a significant inhibition of HT29 tumor growth compared with mismatch- and naked antisense-pretreated control groups (time from 200 to 1000 mm3, 126.9 versus 84.18 and 87.76 days, P<0.005). A potentiation of the antitumor activity was observed in all mice treated with Ku86 ASO-P85-g-PEI (2 kDa) formulation; however, tumor growth inhibition was reversible upon treatment cessation. No morbidity/mortality or changes in histopathology were observed under this treatment regiment. Our results indicate that P85-g-PEI (2 kDa) conjugates may increase the efficacy of Ku86 ASO delivery in management of resistant malignancies, thus providing a rationale for their evaluation in cancer patients in combination with conventional anticancer therapies.

Animals↗

In vitro evidence for homologous recombinational repair in resistance to melphalan.

BACKGROUND: The generation of DNA interstrand cross-links is thought to be important in the cytotoxicity of nitrogen mustard alkylating agents, such as melphalan, which have antitumor activity. Cell lines with mutations in recombinational repair pathways are hypersensitive to nitrogen mustards. Thus, resistance to melphalan may require accelerated DNA repair by either recombinational repair mechanisms involving Rad51-related proteins (including x-ray repair cross-complementing proteins Xrcc2, Xrcc3, and Rad52) or by nonhomologous endjoining involving DNA-dependent protein kinase (DNA-PK) and Ku proteins. We investigated the role of DNA repair in melphalan resistance in epithelial tumor cell lines. METHODS: Melphalan cytotoxicity was determined in 14 epithelial tumor cell lines by use of the sulforhodamine assay. Homologous recombinational repair involving Rad51-related proteins was investigated by determining the levels of Rad51, Rad52, and Xrcc3 proteins and the density of nuclear melphalan-induced Rad51 foci, which represent sites of homologous recombinational repair. Nonhomologous endjoining was investigated by determining the levels of Ku70 and Ku86 proteins and DNA-PK activity. Linear regression analysis was used to analyze correlations between the various protein levels, DNA-PK activity, or Rad51 foci formation and melphalan cytotoxicity. All statistical tests were two-sided. RESULTS: Melphalan resistance was correlated with Xrcc3 levels (r =.587; P =.027) and the density of melphalan-induced Rad51 foci (r =.848; P =.008). We found no correlation between melphalan resistance and Rad51, Rad52, or Ku protein levels or DNA-PK activity. CONCLUSION: Correlations of melphalan resistance in epithelial tumor cell lines with Xrcc3 protein levels and melphalan-induced Rad51 foci density suggest that homologous recombinational repair is involved in resistance to this nitrogen mustard.

Antigens, Nuclear↗

Both extraneuronal monoamine transporter and O(6)-methylguanine-DNA methyltransferase expression influence the antitumor efficacy of 2-chloroethyl-3-sarcosinamide- 1-nitrosourea in human tumor xenografts.

We previously have found that 2-chloroethyl-3-sarcosinamide-1-nitrosourea (SarCNU) is a selective cytotoxin that enters cells via the extraneuronal transporter for monoamine transmitters (EMT). Both in vitro and in vivo studies demonstrated that SarCNU was more effective than BCNU against human gliomas. To clarify whether EMT expression correlates with antitumor efficacy of SarCNU, we determined human EMT (EMTh) and O(6)-methylguanine-DNA methyltransferase (MGMT) expression in nine human xenograft models using semiquantitative reverse-transcription polymerase chain reaction. These results were compared with the antitumor effects of SarCNU and the standard chloroethylnitrosourea antitumor agent 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). There was no significant correlation between EMTh expression and antitumor efficacy of SarCNU or BCNU. Also, there was no significant correlation between MGMT expression and SarCNU efficacy. However, a significant correlation was found between MGMT expression and BCNU antitumor efficacy. Interestingly, multiple regression analysis demonstrated a significant correlation between SarCNU efficacy and EMTh plus MGMT expression, whereas there was no correlation between BCNU efficacy and MGMT plus EMTh expression. Thus, the absence of a linear correlation between SarCNU efficacy and EMTh expression appears to be due, at least in part, to the presence of DNA repair, specifically, MGMT, in these xenograft models. These studies suggest that MGMT expression alone correlates with BCNU activity, whereas both EMTh and MGMT expression are important determinants of SarCNU activity against human tumor xenograft models. SarCNU is in clinical trials and these results may have important clinical implications.

Animals↗

[Expression of extraneuronal monoamine transporter gene and DNA repair gene vis-à-vis with antitumor efficacy of SarCNU in human tumor xenografts].

OBJECTIVE: To clarify if there are any correlations between extraneuronal monoamine transmitters (EMT), DNA repair gene expressions and SarCNU antitumor efficacy. METHODS: EMT, DNA repair gene O6-methylguanine-DNA methyltransferase (MGMT) and excision repair cross-complementing rodent repair deficiency gene (ERCC1-6) expressions in 9 human xenograft tumor models were determined by RT-PCR. The results were compared with the antitumor effects of SarCNU on these tumor xenografts. RESULTS: Multiple regression analysis revealed significant correlations of SarCNU antitumor activity with different combinations of gene expression. The most significant correlation was observed with all of the 4 genes expressed. CONCLUSION: The results suggest that expression of both EMT and DNA repair genes, specifically, MGMT, ERCC2 and ERCC4, are important determinants of SarCNU activity against human tumors. While DNA repair decreases SarCNU's activity by repairing damaged DNA, EMT appears to enhance its antitumor efficacy.

Animals↗

Enhanced antitumor activity of sarCNU in comparison to BCNU in an extraneuronal monoamine transporter positive human glioma xenograft model.

A novel analogue of nitrosoureas, 2-chloroethyl-3-sarcosinamide-1-nitrosourea (SarCNU), has demonstrated increased anticancer effects in vitro and in vivo. Our previous work suggested that SarCNU enters cells via the extraneuronal monoamine transporter (EMT), that contributes to its enhanced cytotoxicity. In the present study, comparative activities of SarCNU and 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) were evaluated in an EMT positive human glioma xenograft model. Athymic nude mice implanted subcutaneously or intracranially with human glioma SHG-44, a cell line that has been confirmed EMT positive by using reverse-transcription polymerase chain reaction (RT-PCR) assay, were treated with SarCNU at an optimal dose of 167 mg/kg, or BCNU at 20 mg/kg or 30 mg/kg, q4d x 3 intraperitoneally (i.p.). In 17 animals with subcutaneous tumor grafts treated with SarCNU, 9 animals became tumor free and 8 demonstrated tumor regression. While in the BCNU treated group, there were only 2 out of 10 mice in the 20 mg/kg group and 2 out of 7 in the 30 mg/kg group, which demonstrated some tumor regression. There were 4 drug related deaths in the BCNU (30 mg/kg) group, while there were no drug related deaths in the SarCNU group. In the intracranially implanted mice, the median survival time in the SarCNU group was more than 130 days, while in the BCNU treated group it was only 22 days which was similar to the control group (18 days). This is the first demonstration that SarCNU, in comparison to BCNU, has enhanced anticancer activity in an EMT positive human glioma xenograft model.

Animals↗

Relationship between O6-methylguanine-DNA methyltransferase levels and clinical response induced by chloroethylnitrosourea therapy in glioma patients.

BACKGROUND: Adjuvant nitrosourea chemotherapy fails to prolong survival significantly as many tumors demonstrate resistance to these drugs. It has been documented in cell lines that O6-methylguanine DNA methyltransferase (MGMT) plays an important role in chloroethylnitrosourea (CENU) drug resistance. METHODS: We evaluated MGMT expression in 22 glioma specimens by using an immunofluorescence assay and compared the results with clinical responses of the patients to CENU-based chemotherapy. RESULTS: Eight tumor samples had no detectable MGMT, whereas other samples had from 9,989 to 982,401 molecules/nucleus. In one group (12 patients), the tumor decreased in size or was stable (effective group), whereas in the other group (10 patients), the tumor demonstrated continuous growth during chemotherapy (progressive group). The Mer- patients (MGMT < 60,000 molecules/nucleus) appeared to have more chance of stable disease or response to CENU therapy than the Mer+ patients (MGMT > 60,000 molecules/nucleus) (X2 = 4.791, p = 0.0286). In patients with glioblastomas multiforme (GBMs), the median time to progression (TTP) of Mer+ patient was shorter than that of Mer- patient (t = 2.04, p = 0.049). As a corollary, the MGMT levels were significantly higher in GBM tumors from the progressive group than those from the effective group (t = 2.26, p = 0.029). However, there was no significant correlation between MGMT levels and either the survival time (r = 0.04, p = 0.8595) or TTP (r = 0.107, p = 0.6444). CONCLUSION: This study suggests that being MGMT positive is indicative of a more aggressive disease that progresses more rapidly with CENU therapy. However, MGMT negative tumors are not always sensitive to CENU agents, suggesting that other factors are also important.

Adult↗

Chlorambucil induction of HsRad51 in B-cell chronic lymphocytic leukemia.

Our previous studies with B-cell chronic lymphocytic leukemia (B-CLL) have suggested that one of the mechanisms of nitrogen mustard (NM) drug resistance is increased repair of drug-induced damage. We have postulated that recombination may play a crucial role in this process. The human homologue of Rad51, (HsRad51), has homology to the RecA protein in Escherichia coli, which is implicated in recombination repair and induction of DNA repair enzymes. In this report, we have examined the expression and distribution of HsRad51 protein in lymphocytes from patients with B-CLL to see whether the expression of HsRad51 is associated with NM damage to the malignant B lymphocytes, specifically chlorambucil (CLB), which is the standard alkylating agent used to treat patients with B-CLL. We have analyzed the intracellular distribution of HsRad51 protein in these lymphocytes before and after treatment with CLB by immunofluorescence. In vitro CLB treatment induces Rad51 expression, as measured by increased immunopositive staining in all CLL samples. In the CLB-resistant CLL lymphocytes, there was a linear correlation between induction of Rad51 protein at 5.4 microM CLB and the in vitro LD50 dose of CLB. Surprisingly, although it has been reported that Rad51 is induced in S phase and only 10% of cells from cell lines expressed positive immunostaining for Rad51, our CLL lymphocytes, which were not subjected to in vitro drug exposure, were 90% positive for Rad51, despite their nonproliferative state, which suggests that there is chronic activation of the protein. Our results suggest that CLB activates HsRad51-directed recombination repair and that this process may be important in NM drug-induced cytotoxicity.

Antineoplastic Agents, Alkylating↗

Extraneuronal monoamine transporter expression and DNA repair vis-à-vis 2-chloroethyl-3-sarcosinamide-1-nitrosourea cytotoxicity in human tumor cell lines.

We previously found that 2-chloroethyl-3-sarcosin-amide-1-nitrosourea (SarCNU), a new chloroethylnitrosourea analogue presently in phase I clinical trials, is a selective cytotoxin that enters cells via the extraneuronal transporter for monoamine transmitters (EMT). In this study, we assessed whether EMT expression correlates with SarCNU cytotoxicity by determining EMT expression in 23 human tumor cell lines with reverse-transcription PCR. Western blot analysis was used to measure protein levels of the DNA repair genes, O6-methylguanine-DNA methyltransferase (MGMT), and excision repair cross-complementing rodent repair deficiency gene 2 (ERCC2). SarCNU cytotoxicity was determined by the sulforhodamine B colorimetric anti-cancer-drug screening assay and correlated with gene expression. Almost all of the cell lines screened were positive for EMT expression. However, seven cell lines (MGR-1, MGR-2, T98-G, SKI-1, SKNSH, 297, and GBM) expressed low levels of EMT. Although there was no linear correlation between SarCNU cytotoxicity and EMT expression, SarCNU cytotoxicity significantly correlated with ERCC2 protein levels, and MGMT-rich (Mer+) cell lines (MGMT protein level >0.1) were more resistant to SarCNU than MGMT-poor (Mer-) cell lines (MGMT protein level <0.1). Moreover, multiple regression analysis indicated that the best correlation with SarCNU cytotoxicity was attainable with EMT plus MGMT and ERCC2 expression. This study suggests that in human tumor cell lines both EMT and DNA repair factors, specifically, MGMT and ERCC2, are important determinants of SarCNU activity. Because EMT is expressed in a wide variety of human tumors, SarCNU should be a more widely effective alternative chemotherapeutic agent.

Antineoplastic Agents↗

Clinical response of O(6)-methylguanine-DNA methyltransferase levels to 1,3-(2-chloroethyl)-1-nitrosourea chemotherapy in glioma patients.

Adjuvant nitrosourea chemotherapy fails to prolong patient survival significantly as many tumors demonstrate resistance to these drugs. It has been documented in cell lines that O(6)-methylguanine-DNA methyltransferase (MGMT) plays an important role in chloroethylnitrosourea (CENU) drug resistance. The authors evaluated MGMT expression in 22 glioma specimens by using an immunofluorescence assay and compared the results with clinical response of the patients to CENU-based chemotherapy. The patients were treated with CENU after evidence of progressive disease following surgery and radiotherapy. Eight tumor samples had no detectable MGMT, whereas other samples had from 9989 to 982,401 molecules/nucleus. In one group (12 patients), the tumor decreased in size or was stable (effective group), whereas in the other group (10 patients), the tumor demonstrated continuous growth during chemotherapy (progressive group). The median time to progression (TTP) was 6.7 months with a median survival of 13 months. The Mer(-) patients (MGMT < 60,000 molecules/nucleus) appeared to have more chance of stable disease or response to CENU therapy than the Mer(+) patients (MGMT > 60,000 molecules/nucleus) (chi-square = 4.791, p = 0.0286). In patients with glioblastomas multiforme (GBMs), the TTP of Mer(+) patients was shorter than that of Mer(-) patients (t = 2.04, p = 0.049). As a corollary, the MGMT levels were significantly higher in GBM tumors from the progressive group than those from the effective group (t = -2.26, p = 0.029). The TTP and survival time in the effective GBM group were also longer than those in the progressive GBM group. However, there was no significant correlation between MGMT levels and either the survival time (r = 0.04, p = 0.8595) or TTP (r = 0.107, p = 0.6444). Results from this study suggested that MGMT positivity is indicative of more aggressive disease that progresses more rapidly when exposed to CENU therapy. However, MGMT-negative tumors are not always sensitive to CENU agents, suggesting that other factors may also be important.

Journal Article↗

Excision repair cross-complementing rodent repair deficiency gene 2 expression and chloroethylnitrosourea resistance in human glioma cell lines.

OBJECTIVE: Nitrosoureas are the standard chemotherapeutic agents for malignant brain tumors. However, their anticancer effects are limited because many tumors are resistant to these agents. Nucleotide excision repair can repair bulky deoxyribonucleic acid adducts, including deoxyribonucleic acid damage induced by ultraviolet light and some chemotherapeutic agents, and may be implicated in nitrosoureas resistance. In this study, we compared excision repair cross-complementing rodent repair deficiency Gene 2 (ERCC2), an important component of the nucleotide excision repair system, with 1 ,3-bis-(2-chloroethyl)-1-nitrosourea or (2-chloroethyl)-3-sarcosinamide-1-nitrosourea resistance in human glioma cell lines. METHODS: ERCC2 expression was evaluated by using established quantitative reverse-transcription polymerase chain reaction. 1,3-Bis-(2-chloroethyl)-1-nitrosourea and (2-chloroethyl)-3-sarcosinamide-1-nitrosourea cytotoxicity were determined by a modification of the sulforhodamine B colorimetric anticancer drug screening assay. RESULTS: A significant correlation between ERCC2 expression and 1 ,3-bis-(2-chloroethyl)-1-nitrosourea or (2-chloroethyl)-3-sarcosinamide-1-nitrosourea cytotoxicity was determined (r=0.737, P=0.0226 and r=0.789, P=0.0113, respectively). CONCLUSION: Our results suggest that nucleotide excision repair, specifically ERCC2, may play an important role in nitrosoureas drug resistance in human gliomas.

Brain Neoplasms↗

2-Chloroethyl-3-sarcosinamide-1-nitrosourea, a novel chloroethylnitrosourea analogue with enhanced antitumor activity against human glioma xenografts.

Nitrosoureas are among the most widely used agents used in the treatment of malignant gliomas. Here, the activity of 2-chloroethyl-3-sarcosinamide-1-nitrosourea (SarCNU) was compared with that of 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU), in vivo against s.c. implanted SF-295 and U-251 central nervous system (CNS) tumor xenografts. When given i.v., q4d for 3 doses, to athymic mice bearing s.c. SF-295 tumors, SarCNU, at an optimum of 167 mg/kg/dose, produced 9 tumor-free animals of 10 total animals, 1 regression, and no evidence of overt toxicity (> or =20% body weight loss). With a similar dosing schedule, BCNU produced no tumor-free animals, six regressions, and one drug-related death at its optimum of 30 mg/kg/dose. Furthermore, SarCNU retained high antitumor activity at two lower dose levels, 66 and 45% of the optimal dose, whereas BCNU demonstrated a progressive loss of antitumor activity at lower doses. Following p.o. administration, SarCNU similarly demonstrated antitumor activity that was superior to that of BCNU. In the U-251 CNS tumor model, SarCNU yielded six of six tumor-free animals at 80 mg/kg/dose with i.p. administration q.d. for 5 days, starting on day 14, whereas BCNU, at 9 mg/kg/dose, yielded three of six tumor-free mice and one drug-related death. Again, SarCNU resulted in tumor-free animals at 66 and 45% of its optimal dose and was relatively nontoxic, in contrast to BCNU. Results of testing to date indicate that SarCNU is clearly more effective than BCNU against the human CNS tumors SF-295 and U-251 in vivo. These results encourage the initiation of clinical trials for SarCNU, in an effort to improve therapeutic approaches to glioma, but clinical trials must determine whether superiority of SarCNU in preclinical models can be extrapolated to patients.

Administration, Oral↗

Quantitation of ERCC-2 gene expression in human tumor cell lines by reverse transcription-polymerase chain reaction in comparison to northern blot analysis.

Excision repair cross-complementing rodent repair deficiency genes (ERCC) are human genes implicated in nucleotide excision repair. ERCC-2 has been implicated in the repair of DNA damaged by chemotherapeutic agents, and may thus play an important role in anticancer drug resistance. ERCC-2 gene expression is low in primary tumor samples rendering it difficult to quantitate. We have developed a semiquantitative method to measure ERCC-2 gene expression utilizing reverse transcription-polymerase chain reaction (RT-PCR). Total RNA extracted from established human tumor cell lines was reverse-transcribed to obtain cDNA. Serially diluted reference ERCC-2 DNA fragment was amplified by PCR to obtain a 617-bp fragment. A standard curve was then created using densitometry readings of the 617-bp bands on agarose gel. A fixed amount of sample cDNA from each cell line was amplified at the same time and the resultant PCR product was read by densitometer. Using the standard curve, ERCC-2 gene expression in a given amount of total RNA was quantitated and normalized to beta-actin expression. There was minimal variation in three repeated experiments with PCR amplification. ERCC-2 gene expression determined by this semiquantitative PCR was also correlated to ERCC-2 quantitation by Northern blot analysis, with a significant concordance (r = 0.912, P = 0.0002). We also successfully applied this sensitive method to quantify five clinical glioma samples.

Actins↗

Evidence for nucleotide excision repair as a modifying factor of O6-methylguanine-DNA methyltransferase-mediated innate chloroethylnitrosourea resistance in human tumor cell lines.

We examined the O6-methylguanine-DNA methyltransferase (MGMT) protein as well as MGMT activity levels and the excision repair cross-complementing rodent repair deficiency gene, ERCC2 (XPD), protein levels in 14 human tumor cell lines not selected for chloroethylnitrosourea (CENU) resistance. These results were compared with 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU) cytotoxicity and UV light sensitivity. MGMT protein correlated significantly with MGMT activity (r = 0.9497, p = 0.0001). There was no significant linear correlation between BCNU cytotoxicity and MGMT content as determined by both Western analysis (r = 0.139, p = 0. 6348) and activity assay (r = 0.131, p = 0.6515). However, MGMT-rich cell lines were found to be more resistant than MGMT-poor cell lines to BCNU (t = 2.2375, p = 0.0225) but not to UV (t = 1.1734, p = 0.1317). Furthermore, the most BCNU-sensitive cell lines were all MGMT-poor. UV sensitivity was significantly correlated to BCNU cytotoxicity (r = 0.858, p = 0.0001). Significant correlations were found between ERCC2 protein levels and BCNU cytotoxicity (r = 0.786, p = 0.0009) or UV sensitivity (r = 0.874, p = 0.0001). Our results confirm that MGMT plays an important role in CENU resistance, but not in UV resistance. The correlation of UV sensitivity with BCNU cytotoxicity suggests that nucleotide excision repair is an important modifying factor of MGMT-mediated innate CENU resistance in human tumor cell lines, especially in highly resistant cell lines. ERCC2 may be implicated in this process.

Antineoplastic Agents, Alkylating↗

Characterization of the catecholamine extraneuronal uptake2 carrier in human glioma cell lines SK-MG-1 and SKI-1 in relation to (2-chloroethyl)-3-sarcosinamide-1-nitrosourea (SarCNU) selective cytotoxicity.

Transport of (2-chloroethyl)-3-sarcosinamide-1-nitrosourea (SarCNU) and (-)-norepinephrine was investigated in SarCNU-sensitive SK-MG-1 and -resistant SKI-1 human glioma cell lines. [3H]SarCNU influx was inhibited by SarCNU, sarcosinamide, and (+/-)-epinephrine in SK-MG-1 cells with competitive inhibition observed by (+/-)-epinephrine (Ki = 140 +/- 12 microM) and (+/-)-norepinephrine (Ki = 255 +/- 41 microM). No effect on influx was detected in SKI-1 cells. [3H](-)-Norepinephrine influx was linear to 15 sec in both cell lines and temperature dependent only in SK-MG-1 cells. Influx of [3H](-)-norepinephrine was found to be saturable in SK-MG-1 (K(m) = 148 +/- 28 microM, Vmax = 1.23 +/- 0.18 pmol/microL intracellular water/sec) but not in SKI-1 cells. In SK-MG-1 cells, [3H](-)-norepinephrine influx was found to be inhibited competitively by (-)-epinephrine (Ki = 111 +/- 7 microM) and SarCNU (Ki = 1.48 +/- 0.22 mM). Ouabain and KCl were able to inhibit the [3H](-)-norepinephrine influx in SK-MG-1 cells, consistent with influx being driven by membrane potential. Several catecholamine uptake2 inhibitors were able to reduce significantly the influx of [3H](-)-norepinephrine and [3H]SarCNU with no inhibition by a catecholamine uptake1 inhibitor. These findings suggest that increased sensitivity of SK-MG-1 to SarCNU is secondary to enhanced accumulation of SarCNU mediated via the catecholamine extraneuronal uptake2 transporter, which is not detectable in SKI-1 cells. The introduction of SarCNU into clinical trials will confirm if increased uptake via the catecholamine extraneuronal uptake2 transporter will result in increased antitumor activity.

Antineoplastic Agents↗