The Involvement of Novel Protein Kinase C Isozymes in Influencing Sensitivity of Breast Cancer MCF-7 Cells to Tumor Necrosis Factor-α

Basu, Alakananda

doi:10.1124/mol.53.1.105

Cited by 34 publications

(30 citation statements)

References 28 publications

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“…Unique up-regulation of PKC-has been noted previously in interleukin 2-producing EL4 mouse thymoma cells (12), in murine keratinocytes (39), and in breast cancer lines (40), and the lack of down-regulation was observed also in A431 human epidermal carcinoma cells (41). Basu (40) observed down-regulation of PKC-after treatment of MCF-7 cells with BIM, but we did not see a BIM-induced down-regulation of PKC-expression in the astrocytic cell lines (data not shown).…”

Section: Discussionmentioning

confidence: 88%

Phorbol 12-Myristate 13-Acetate Induces Protein Kinase Cη-specific Proliferative Response in Astrocytic Tumor Cells

Hussaini

Karns

Vinton

et al. 2000

Journal of Biological Chemistry

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Section: Discussionmentioning

confidence: 88%

Phorbol 12-Myristate 13-Acetate Induces Protein Kinase Cη-specific Proliferative Response in Astrocytic Tumor Cells

Hussaini

Karns

Vinton

et al. 2000

Journal of Biological Chemistry

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“…Activation of PKC⑀ Is Necessary for Its Antiapoptotic Action-We have previously shown that PKC activators protect cells against TNF-induced cytotoxicity (22). Fig.…”

Section: Figmentioning

confidence: 99%

Proteolytic Activation of Protein Kinase C-ε by Caspase-mediated Processing and Transduction of Antiapoptotic Signals

Basu

Sun³

et al. 2002

Journal of Biological Chemistry

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Several novel protein kinase C (PKC) isozymes have been identified as substrates for caspase-3. We have previously shown that novel PKC⑀ is cleaved during apoptosis in MCF-7 cells that lack any functional caspase-3. In the present study, we show that in vitro-translated PKC⑀ is processed by human recombinant caspase-3, -7, and -9. Tumor necrosis factor-␣ (TNF) triggered processing of PKC⑀ to a 43-kDa carboxyl-terminal fragment, and cell-permeable caspase inhibitors prevented TNF-induced processing of PKC⑀ in MCF-7 cells. PKC⑀ was cleaved primarily at the SSPD2G site to generate two fragments with an approximate molecular mass of 43 kDa. It was also cleaved at the DDVD2C site to generate two fragments with molecular masses of 52 and 35 kDa. Treatment of MCF-7 cells with TNF resulted in the activation of PKC⑀, and mutation at the SSPD2G (D383A) site inhibited proteolytic activation of PKC⑀. Overexpression of wild-type but not dominant-negative PKC⑀ in MCF-7 cells delayed TNF-induced apoptosis, and mutation at the D383A site prevented antiapoptotic activity of PKC⑀. These results suggest that cleavage of PKC⑀ by caspase-7 at the SSPD2G site results in the activation of PKC⑀. Furthermore, activation of PKC⑀ was associated with its antiapoptotic function.

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“…Phase II clinical trials of bryostatin 1 are under way for the treatment of leukemias, lymphomas, melanomas, and solid tumors (26). Bryostatin 1 also shows promise for treatment of ovarian and breast cancers and for enhancing lymphocyte survival during radiation treatment (3,4,5,12,13,16,20,21,28,32,33). Other bryostatins may prove to be valuable therapeutic agents as well (19).…”

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confidence: 99%

Evidence for the Biosynthesis of Bryostatins by the Bacterial Symbiont “ Candidatus Endobugula sertula” of the Bryozoan Bugula neritina

Davidson

Allen

Lim

et al. 2001

Appl Environ Microbiol

263

237

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The marine bryozoan, Bugula neritina, is the source of the bryostatins, a family of macrocyclic lactones with anticancer activity. Bryostatins have long been suspected to be bacterial products. B. neritina harbors the uncultivated gamma proteobacterial symbiont "Candidatus Endobugula sertula." In this work several lines of evidence are presented that show that the symbiont is the most likely source of bryostatins. Bryostatins are complex polyketides similar to bacterial secondary metabolites synthesized by modular type I polyketide synthases (PKS-I). PKS-I gene fragments were cloned from DNA extracted from the B. neritina-"E. sertula" association, and then primers specific to one of these clones, KSa, were shown to amplify the KSa gene specifically and universally from total B. neritina DNA. In addition, a KSa RNA probe was shown to bind specifically to the symbiotic bacteria located in the pallial sinus of the larvae of B. neritina and not to B. neritina cells or to other bacteria. Finally, B. neritina colonies grown in the laboratory were treated with antibiotics to reduce the numbers of bacterial symbionts. Decreased symbiont levels resulted in the reduction of the KSa signal as well as the bryostatin content. These data provide evidence that the symbiont E. sertula has the genetic potential to make bryostatins and is necessary in full complement for the host bryozoan to produce normal levels of bryostatins. This study demonstrates that it may be possible to clone bryostatin genes from B. neritina directly and use these to produce bryostatins in heterologous host bacteria.

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The Involvement of Novel Protein Kinase C Isozymes in Influencing Sensitivity of Breast Cancer MCF-7 Cells to Tumor Necrosis Factor-α

Cited by 34 publications

References 28 publications

Phorbol 12-Myristate 13-Acetate Induces Protein Kinase Cη-specific Proliferative Response in Astrocytic Tumor Cells

Phorbol 12-Myristate 13-Acetate Induces Protein Kinase Cη-specific Proliferative Response in Astrocytic Tumor Cells

Proteolytic Activation of Protein Kinase C-ε by Caspase-mediated Processing and Transduction of Antiapoptotic Signals

Evidence for the Biosynthesis of Bryostatins by the Bacterial Symbiont “ Candidatus Endobugula sertula” of the Bryozoan Bugula neritina

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