Faculty

Charles J Gomer, PhD
Charles J Gomer, PhD
Professor of Pediatrics;Vice Chair, Faculty Development (Pediatrics CHLA);Chair, FAPTC
Pediatrics
CHL Mail Stop 67 Off Campus Los Angeles
My research program is involved in the areas of radiation biology, photobiology and laser medicine. A large portion of our work focuses on the examination of photodynamic therapy, in which tumor localizing photosensitizers are exposed to laser generated light for the selective generation of reactive oxygen species. PDT is used in the clinical treatment of solid tumors as well as for the treatment of vascular and dermal proliferative disorders. We are using molecular, biochemical, cellular and in-vivo methodologies to examine the biological consequences of exposure to reactive oxygen species and oxidative stress.

One area of investigation involves the use of the inducible heat shock (hsp) promoter as a molecular switch for the selective activation of heterologous genes. We have shown that photooxidative stress and laser generated hyperthermia are strong transcriptional inducers of the heat shock proteins. We have also shown that photooxidative stress can drive selective and temporal expression of reporter genes ligated to the hsp promoter. Work is now underway to evaluate our hypothesis that targeted gene therapy using recombinant constructs with oxidative stress and heat inducible promoters will provide a novel mechanism for expression of cytotoxins, growth factors, immuno-modulators, suppressor genes and antisense molecules. A second area of investigation involves the analysis of wild type and mutated p53 tumor suppressor gene expression on sensitivity of tumor cells to photooxidative stress. Loss of p53 function has been correlated with decreased sensitivity to chemotherapy and radiation therapy in a variety of human tumors. We are currently evaluating cell photosensitivity, cell cycle perturbations and apoptosis in tumor cell lines exhibiting either wild type p53, mutated p53 or deleted p53 expression. We have also isolated a cell line exhibiting a photooxidative stress resistant phenotype and we are evaluating the molecular determinants responsible for inducing cellular resistant to oxidative stress. A third area of investigation involves the use of photosensitizers and laser generated light for the treatment of the pediatric eye tumor retinoblastoma.

Corrigendum to "Naturally occurring sesquiterpene lactones and their semi-synthetic derivatives modulate PGE2 levels by decreasing COX2 activity and expression" [Heliyon 5 (3) (March 2019) e01366] Heliyon. 2019 04; 5(4):e01513. . View in PubMed

Naturally occurring sesquiterpene lactones and their semi-synthetic derivatives modulate PGE2 levels by decreasing COX2 activity and expression Heliyon. 2019 03; 5(3):e01366. . View in PubMed

Rational drug design and synthesis of new a-Santonin derivatives as potential COX-2 inhibitors Bioorg Med Chem Lett. 2018 04 01; 28(6):993-996. . View in PubMed

Rabbit model of ocular indirect photodynamic therapy using a retinoblastoma xenograft Graefes Arch Clin Exp Ophthalmol. 2017 Dec; 255(12):2363-2373. . View in PubMed

Targeting Survivin Enhances Chemosensitivity in Retinoblastoma Cells and Orthotopic Tumors PLoS One. 2016; 11(4):e0153011. . View in PubMed

Induction of prosurvival molecules during treatment: rethinking therapy options for photodynamic therapy J Natl Compr Canc Netw. 2012 Oct 01; 10 Suppl 2:S35-9. . View in PubMed

Pro-apoptotic and anti-inflammatory properties of the green tea constituent epigallocatechin gallate increase photodynamic therapy responsiveness Lasers Surg Med. 2011 Sep; 43(7):644-50. . View in PubMed

Enhancement of photodynamic therapy by 2,5-dimethyl celecoxib, a non-cyclooxygenase-2 inhibitor analog of celecoxib Cancer Lett. 2011 May 01; 304(1):33-40. . View in PubMed

Targeting the 90 kDa heat shock protein improves photodynamic therapy Cancer Lett. 2010 Mar 28; 289(2):188-94. . View in PubMed

Targeting the tumor microenvironment using photodynamic therapy combined with inhibitors of cyclooxygenase-2 or vascular endothelial growth factor Methods Mol Biol. 2010; 635:121-32. . View in PubMed

Identification of MAP kinase pathways involved in COX-2 expression following photofrin photodynamic therapy Methods Mol Biol. 2010; 635:47-63. . View in PubMed

Cyclooxygenase-2 expression induced by photofrin photodynamic therapy involves the p38 MAPK pathway Photochem Photobiol. 2008 Mar-Apr; 84(2):509-14. . View in PubMed

Multiple components of photodynamic therapy can phosphorylate Akt Photochem Photobiol. 2007 Sep-Oct; 83(5):1029-33. . View in PubMed

Survivin, a member of the inhibitor of apoptosis family, is induced by photodynamic therapy and is a target for improving treatment response Cancer Res. 2007 May 15; 67(10):4989-95. . View in PubMed

Photodynamic therapy: combined modality approaches targeting the tumor microenvironment Lasers Surg Med. 2006 Jun; 38(5):516-21. . View in PubMed

Avastin enhances photodynamic therapy treatment of Kaposi's sarcoma in a mouse tumor model J Environ Pathol Toxicol Oncol. 2006; 25(1-2):251-9. . View in PubMed

Celecoxib and NS-398 enhance photodynamic therapy by increasing in vitro apoptosis and decreasing in vivo inflammatory and angiogenic factors Cancer Res. 2005 Oct 15; 65(20):9473-8. . View in PubMed

Spontaneous and controllable activation of suicide gene expression driven by the stress-inducible grp78 promoter resulting in eradication of sizable human tumors Hum Gene Ther. 2004 Jun; 15(6):553-61. . View in PubMed

The matrix metalloproteinase inhibitor prinomastat enhances photodynamic therapy responsiveness in a mouse tumor model Cancer Res. 2004 Apr 01; 64(7):2328-32. . View in PubMed

CHOP activation by photodynamic therapy increases treatment induced photosensitization Lasers Surg Med. 2004; 35(5):336-41. . View in PubMed

Cyclooxygenase-2 inhibitor treatment enhances photodynamic therapy-mediated tumor response Cancer Res. 2002 Jul 15; 62(14):3956-61. . View in PubMed

Enhanced photodynamic therapy efficacy with inducible suicide gene therapy controlled by the grp promoter Cancer Res. 2002 Mar 01; 62(5):1458-61. . View in PubMed

Loss of p53 function confers high-level multidrug resistance in neuroblastoma cell lines Cancer Res. 2001 Aug 15; 61(16):6185-93. . View in PubMed

Antiangiogenic treatment enhances photodynamic therapy responsiveness in a mouse mammary carcinoma Cancer Res. 2000 Aug 01; 60(15):4066-9. . View in PubMed

Photodynamic therapy-mediated oxidative stress as a molecular switch for the temporal expression of genes ligated to the human heat shock promoter Cancer Res. 2000 Mar 15; 60(6):1637-44. . View in PubMed

Photodynamic therapy sensitivity is not altered in human tumor cells after abrogation of p53 function Cancer Res. 1999 Jan 15; 59(2):331-5. . View in PubMed

Photodynamic therapy J Natl Cancer Inst. 1998 Jun 17; 90(12):889-905. . View in PubMed

Differential photosensitivity in wild-type and mutant p53 human colon carcinoma cell lines J Photochem Photobiol B. 1998 Feb; 42(2):104-7. . View in PubMed

Increased photosensitivity in HL60 cells expressing wild-type p53 Photochem Photobiol. 1997 Aug; 66(2):265-70. . View in PubMed

Identification of genes associated with resistance to photodynamic therapy-mediated oxidative stress Methods Mol Biol. 1997; 85:263-76. . View in PubMed

Chemotherapy plus local treatment in the management of intraocular retinoblastoma Arch Ophthalmol. 1996 Nov; 114(11):1348-56. . View in PubMed

Cellular targets and molecular responses associated with photodynamic therapy J Clin Laser Med Surg. 1996 Oct; 14(5):315-21. . View in PubMed

Photodynamic therapy-mediated oxidative stress can induce expression of heat shock proteins Cancer Res. 1996 May 15; 56(10):2355-60. . View in PubMed

Decreased expression and function of alpha-2 macroglobulin receptor/low density lipoprotein receptor-related protein in photodynamic therapy-resistant mouse tumor cells Cancer Res. 1995 May 01; 55(9):1820-3. . View in PubMed

Photosensitization with derivatives of chlorin p6 J Photochem Photobiol B. 1995 Apr; 28(1):13-8. . View in PubMed

Clinical and preclinical photodynamic therapy Lasers Surg Med. 1995; 17(1):2-31. . View in PubMed

Photodynamic therapy mediated induction of early response genes Cancer Res. 1994 Mar 01; 54(5):1374-80. . View in PubMed

Nuclear factor kappa B binding activity in mouse L1210 cells following photofrin II-mediated photosensitization Photochem Photobiol. 1993 Nov; 58(5):753-6. . View in PubMed

Adriamycin resistance in Chinese hamster fibroblasts following oxidative stress induced by photodynamic therapy Photochem Photobiol. 1993 Oct; 58(4):581-8. . View in PubMed

Establishment of a Chinese hamster ovary cell line that expresses grp78 antisense transcripts and suppresses A23187 induction of both GRP78 and GRP94 J Cell Physiol. 1992 Dec; 153(3):575-82. . View in PubMed

Metabolic properties and photosensitizing responsiveness of mono-L-aspartyl chlorin e6 in a mouse tumor model Cancer Res. 1992 May 15; 52(10):2890-3. . View in PubMed

Glucose regulated protein induction and cellular resistance to oxidative stress mediated by porphyrin photosensitization Cancer Res. 1991 Dec 15; 51(24):6574-9. . View in PubMed

Preclinical examination of first and second generation photosensitizers used in photodynamic therapy Photochem Photobiol. 1991 Dec; 54(6):1093-107. . View in PubMed

Isolation and initial characterization of mouse tumor cells resistant to porphyrin-mediated photodynamic therapy Cancer Res. 1991 Aug 15; 51(16):4243-9. . View in PubMed

Increased transcription and translation of heme oxygenase in Chinese hamster fibroblasts following photodynamic stress or Photofrin II incubation Photochem Photobiol. 1991 Feb; 53(2):275-9. . View in PubMed

Direct comparison of in-vitro and in-vivo Photofrin-II mediated photosensitization using a pulsed KTP pumped dye laser and a continuous wave argon ion pumped dye laser Lasers Surg Med. 1991; 11(5):404-10. . View in PubMed

Porphyrin photosensitivity in cell lines expressing a heat-resistant phenotype Cancer Res. 1990 Sep 01; 50(17):5365-8. . View in PubMed

Tissue distribution and photosensitizing properties of mono-L-aspartyl chlorin e6 in a mouse tumor model Cancer Res. 1990 Jul 01; 50(13):3985-90. . View in PubMed

Systemic toxicity in mice induced by localized porphyrin photodynamic therapy Cancer Res. 1990 Feb 01; 50(3):539-43. . View in PubMed

Properties and applications of photodynamic therapy Radiat Res. 1989 Oct; 120(1):1-18. . View in PubMed

Tissue concentrations of doxorubicin in animal models with engrafted intraocular tumours In Vivo. 1989 Sep-Oct; 3(5):315-7. . View in PubMed

Laser-induced hyperthermia of ocular tumors Appl Opt. 1989 Jun 15; 28(12):2280-7. . View in PubMed

Photodynamic therapy in the treatment of malignancies Semin Hematol. 1989 Jan; 26(1):27-34. . View in PubMed

Differential cell photosensitivity following porphyrin photodynamic therapy Cancer Res. 1988 Aug 15; 48(16):4539-42. . View in PubMed

Ineffective photodynamic therapy (PDT) in a poorly vascularized xenograft model Br J Cancer. 1988 May; 57(5):455-8. . View in PubMed

Transformation and mutagenic potential of porphyrin photodynamic therapy in mammalian cells Int J Radiat Biol Relat Stud Phys Chem Med. 1988 Apr; 53(4):651-9. . View in PubMed

What makes a good photosensitizer for photodynamic therapy? J Photochem Photobiol B. 1988 Mar; 1(3):376-8.. View in PubMed

Molecular, cellular, and tissue responses following photodynamic therapy Lasers Surg Med. 1988; 8(5):450-63. . View in PubMed

The influence of sodium pentobarbital anesthesia on in vivo photodynamic therapy Photochem Photobiol. 1987 Nov; 46(5):843-6. . View in PubMed

The evolution of photodynamic therapy techniques in the treatment of intraocular tumors Photochem Photobiol. 1987 Nov; 46(5):919-23. . View in PubMed

The effect of localized porphyrin photodynamic therapy on the induction of tumour metastasis Br J Cancer. 1987 Jul; 56(1):27-32. . View in PubMed

Expression of potentially lethal damage in Chinese hamster cells exposed to hematoporphyrin derivative photodynamic therapy Cancer Res. 1986 Jul; 46(7):3348-52. . View in PubMed

Photodynamic therapy of intraocular tumors: examination of hematoporphyrin derivative distribution and long-term damage in rabbit ocular tissue Cancer Res. 1985 Aug; 45(8):3718-25. . View in PubMed

In vitro and in vivo light dose rate effects related to hematoporphyrin derivative photodynamic therapy Cancer Res. 1985 May; 45(5):1973-7. . View in PubMed

Examination of potentially lethal damage in cells treated with hematoporphyrin derivative and red light Adv Exp Med Biol. 1985; 193:147-53. . View in PubMed

Acute skin response in albino mice following porphyrin photosensitization under oxic and anoxic conditions Photochem Photobiol. 1984 Oct; 40(4):435-9. . View in PubMed

Action spectrum (620-640 nm) for hematoporphyrin derivative induced cell killing Photochem Photobiol. 1984 Mar; 39(3):365-8. . View in PubMed

Documentation of radioactive contaminants in tritium labeled hematoporphyrin derivative Prog Clin Biol Res. 1984; 170:591-600. . View in PubMed

Examination of action spectrum, dose rate and mutagenic properties of hematoporphyrin derivative photoradiation therapy Prog Clin Biol Res. 1984; 170:459-69. . View in PubMed

Hematoporphyrin derivative photoradiation induced damage to normal and tumor tissue of the pigmented rabbit eye Curr Eye Res. 1984 Jan; 3(1):229-37. . View in PubMed

Observations in studies of quantitative kinetics of tritium labelled hematoporphyrin derivatives (HpDI and HpDII) in the normal and neoplastic rat brain model J Neurooncol. 1984; 2(4):361-70. . View in PubMed

Comparison of mutagenicity and induction of sister chromatid exchange in Chinese hamster cells exposed to hematoporphyrin derivative photoradiation, ionizing radiation, or ultraviolet radiation Cancer Res. 1983 Jun; 43(6):2622-7. . View in PubMed

Hematoporphyrin derivative photoradiation therapy for the treatment of intraocular tumors: examination of acute normal ocular tissue toxicity Cancer Res. 1983 Feb; 43(2):721-7. . View in PubMed

Preclinical evaluation of hematoporphyrin derivative for the treatment of intraocular tumors: a preliminary report Adv Exp Med Biol. 1983; 160:109-14. . View in PubMed

Recent developments in the genetics and treatment of retinoblastoma Birth Defects Orig Artic Ser. 1982; 18(6):681-7. . View in PubMed

Tissue distribution of 3H-hematoporphyrin derivative in athymic "nude" mice heterotransplanted with human retinoblastoma Invest Ophthalmol Vis Sci. 1982 Jan; 22(1):118-20. . View in PubMed

DNA damage and repair in CHO cells following hematoporphyrin photoradiation Cancer Lett. 1980 Dec; 11(2):161-7. . View in PubMed

Photoinactivation of Chinese hamster cells by hematoporphyrin derivative and red light Photochem Photobiol. 1980 Sep; 32(3):341-8. . View in PubMed

Acute skin phototoxicity in hairless mice following exposure to crude shale oil or natural petroleum oil Toxicology. 1980; 18(1):75-85. . View in PubMed

Initial United States clinical and pharmacologic evaluation of misonidazole (Ro-07-0582), an hypoxic cell radiosensitizer Int J Radiat Oncol Biol Phys. 1979 Jun; 5(6):775-86. . View in PubMed

Relationship between misonidazole toxicity and core temperature in C3H mice Radiat Res. 1979 May; 78(2):329-33. . View in PubMed

Determination of [3H]- and [14C]hematoporphyrin derivative distribution in malignant and normal tissue Cancer Res. 1979 Jan; 39(1):146-51. . View in PubMed

The hypoxic cell sensitizer programme in the United States Br J Cancer Suppl. 1978 Jun; 3:276-80. . View in PubMed

The demonstration of in vivo misonidazole tumour toxicity using post radiation hypoxia Br J Cancer Suppl. 1978 Jun; 3:228-31. . View in PubMed

The effect of radiation on tumor blood flow and distribution of labelled methotrexate using an animal model system Bibl Anat. 1977; (15 Pt 1):281-4. . View in PubMed

An investigation of the radiosensitizing effects of Ro-07-0582 on hypoxic skin in primates Int J Radiat Oncol Biol Phys. 1976 Jul-Aug; 1(7-8):593-9. . View in PubMed

Energetics and efficiency of photoinactivation of murine tumor cells containing hematoporphyrin Cancer Res. 1976 Jul; 36(7 PT 1):2330-3. . View in PubMed

Identification of singlet oxygen as the cytotoxic agent in photoinactivation of a murine tumor Cancer Res. 1976 Jul; 36(7 PT 1):2326-9. . View in PubMed

Letter: An investigation of the pharmacological and radiosensitizing effects of the 2-nitroimidazole Ro-07-0582 in primates Br J Radiol. 1976 Mar; 49(579):294-5. . View in PubMed

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